RU2731985C1 - Method and system for starting internal combustion engine - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: disclosed is a method for starting an internal combustion engine (ICE) having a crankshaft and an electric rotary device (ERD) operatively connected to a crankshaft. Absolute angular position of the crankshaft is determined, which is related to the position of the upper dead point of the piston in the combustion chamber of ICE. At the first level electric power supply is supplied to ERD for crankshaft rotation. Then, at the second level, electric power is supplied to the ERD more than at the first level, when the piston reaches the preset position before the TDC position. Fuel is injected into the combustion chamber after the piston moves beyond the TDC position. Then fuel ignites. ICE implementation is started in less than 110 degrees of crankshaft turn.

EFFECT: invention discloses a method for starting an internal combustion engine.

23 cl, 22 dwg, 1 tbl

Description

CROSS-REFERENCE

[0001] This application claims priority from Provisional US Patent Application No. 62 / 458,882, filed February 14, 2017, the entire contents of which are incorporated herein by reference. As applied to the United States, this application is a partial continuation of International Patent Application No. PCT / IB 2016/056824, filed November 11, 2016, which claims priority over US Provisional Patent Application No. 62 / 254,421, filed November 12, 2015. , the entire contents of which are incorporated herein by reference.

FIELD OF TECHNOLOGY

[0002] The present technology relates to a method and system for starting an internal combustion engine.

LEVEL OF TECHNOLOGY

[0003] For starting an internal combustion engine of small vehicles such as a snowmobile, a reversing starter is sometimes provided. To start the engine, the user pulls on the recoil starter cord, which causes the engine to rotate. If the crankshaft turns fast enough, the engine may start. Otherwise, pull the cord again until the engine starts.

[0004] To facilitate engine starting, some vehicles have been equipped with an electric starting system. This system consists of an electric motor, known as a starter, that engages and turns a driven gear connected to the crankshaft via a Bendix ™ mechanism when the ignition key is turned or the start button is pressed by the user. The starter motor turns the crankshaft fast enough to allow the engine to start and, once the engine has started, disengages the driven gear and disengages. The vehicle has a battery to supply electrical current to the starter to turn the crankshaft.

[0005] Despite the great convenience for the user, electric starting systems of the type described above have some disadvantages. The battery, starter and related components add weight to the vehicle. As can be understood, the additional weight decreases the fuel efficiency of the vehicle and can affect the handling of the vehicle. In the case of snowmobiles, this weight also makes it difficult for the snowmobile to reach the snowy high point. These electric starting systems also require additional assembly steps during vehicle manufacturing and take up space inside the vehicle.

[0006] An electrical generator is operatively coupled to the engine crankshaft to recharge the battery and to provide electrical current necessary for the operation of various vehicle components immediately after starting the engine. As the crankshaft turns the rotor of the electric generator, the generator generates electricity.

[0007] In recent years, some vehicles have been equipped with engine-generator units, also called starter-generators, which replace the starter and electric generator. The engine generator is functionally connected to the crankshaft in a manner similar to the aforementioned electrical generator. The engine-generator block can be used as a starter or as a generator. By supplying current to the engine / generator block, the engine / generator block functions as a starter and turns the crankshaft to enable the engine to start. When the engine generator functions as a generator, the rotation of the crankshaft generates electricity from the engine generator. As can be understood, the use of such systems eliminates some of the disadvantages of starting systems using separate starters and electrical generators.

[0008] To start the engine, the torque applied to the crankshaft to turn it must be large enough to overcome the compression inside the engine cylinders resulting from the upward movement of the pistons in their respective cylinders as the crankshaft rotates. To deliver a given amount of torque, the engine-generator unit must be large enough to function properly as a starter.

[0009] Another problem concerns the duration of the starting procedure for an internal combustion engine, which should be as fast as possible.

[0010] Another problem relates to motor generator control. When functioning as a starter, the engine generator as a whole operates at low rotational speeds sufficient to allow ignition to occur in the internal combustion engine. This operation requires the supply of some voltage to the engine-generator by the electric starting system. When functioning as a generator, the engine-generator provides electrical power over a wide range of rotational speeds of the internal combustion engine, often well above the cranking speed. Without specific voltage management solutions, a motor generator operating at high rpm can produce voltages that far exceed the needs of various vehicle components.

[0011] Thus, there is a need for a method and system for starting an internal combustion engine that overcomes at least some of the above disadvantages.

DISCLOSURE OF THE INVENTION

[0012] The object of the present technology is to eliminate at least some of the disadvantages of the prior art.

[0013] The present technology provides a system supporting an electric starting procedure for an internal combustion engine (ICE) and a method for electric starting an ICE that uses an electric rotary device (EPD) connected to a crankshaft to start an engine. The method provides the ability to electrically start the engine using a power source that is smaller and lighter than traditional batteries. The sensor transmits to the controller the reading of the absolute angular position of the crankshaft of the internal combustion engine or the reading of the absolute angular position of the component of the internal combustion engine rotating synchronously with the crankshaft. This reading is available when the ICE is stopped, at the beginning of the start-up procedure, and while the ICE is running. From this reading, the controller recognizes the position of the internal combustion engine piston. When the internal combustion engine is stopped, the piston is usually in the first predetermined position due to the configuration of the exhaust ports in the cylinder in which the piston is located. The controller determines the first level of torque that will move the piston from the first preset position to the second at the top dead center (TDC) position. During this time, the controller detects a second torque level higher than the second torque level, which will drive the piston past the TDC position. Fuel injection into the cylinder and ignition will occur after the piston has passed the TDC position.

[0014] In a first aspect, the present technology provides a method for starting an internal combustion engine (ICE) having a crankshaft and an electric rotary device (EPD) operatively coupled to the crankshaft. The absolute angular position of the crankshaft is determined, the absolute angular position of the crankshaft is related to the angular position of the EPU rotor. At the first level, electrical power is supplied to the EPU to rotate the crankshaft. At the second level, the supply of electric power to the EPU is greater than at the first level, when the EPU rotor reaches a given angular position.

[0015] In some implementations of the present technology, the method further includes calculating a first level of electrical power supply so that the EPU generates sufficient torque to rotate the crankshaft until the rotor reaches a predetermined angular position; and calculating the second level of electrical power supply so that the EPC generates sufficient torque to rotate the crankshaft after the predetermined angular position of the rotor.

[0016] In some implementations of the present technology, the calculation of the first level of power supply includes the use of vector control of the power supply at the first level, taking into account the preliminary determination of sufficient torque to rotate the crankshaft until the rotor reaches a predetermined angular position; and calculating the second level of power supply includes using vector control of power supply at the second level, taking into account the preliminary determination of sufficient torque to rotate the crankshaft after a given angular position of the rotor.

[0017] In some implementations of the present technology, the method further includes supplying power to an absolute position sensor used to determine the absolute angular position of the crankshaft when the engine is stopped.

[0018] In some implementations of the present technology, the method further includes supplying power to the absolute position sensor while the crankshaft is rotating.

[0019] In some implementations of the present technology, the method further includes gradually increasing the supply of electrical power to the EPC from the initial level to the first level before supplying electrical power to the EPC at the second level.

[0020] In some implementations of the present technology, the absolute angular position of the crankshaft is further related to the position of the piston in the combustion chamber of the internal combustion engine relative to the piston top dead center (TDC) position.

[0021] In some implementations of the present technology, the supply of electrical power to the EPU at the second level begins when the piston reaches a predetermined position before the TDC position; and the method further includes injecting fuel into the combustion chamber of the internal combustion engine when the piston passes the TDC position for the first time, and igniting the fuel in the combustion chamber.

[0022] In some implementations of the present technology, the method further includes determining the first level of electrical power supplied to the EPC from the initial angular position of the crankshaft.

[0023] In some implementations of the present technology, the initial crankshaft angular position is the position of the crankshaft when the engine is stopped.

[0024] In some implementations of the present technology, the initial angular position is a range of 80 to 100 degrees before the TDC position.

[0025] In some implementations of the present technology, supplying electrical power to the EPC until the piston reaches a predetermined position before the TDC position causes the gases to be displaced from the combustion chamber.

[0026] In some implementations of the present technology, the target position before the TDC position is determined in accordance with the configuration of the ICE outlets.

[0027] In some implementations of the present technology, the target position before the TDC position is in the range of 0 to 50 degrees before the TDC position.

[0028] In some implementations of the present technology, the method further includes stopping the supply of electrical power to the EPC after starting the ICE.

[0029] In some implementations of the present technology, the supply of electrical power to the EPC is stopped when the crankshaft speed reaches a minimum threshold.

[0030] In some implementations of the present technology, the fuel is ignited before the piston passes the TDC position a second time.

[0031] In some implementations of the present technology, fuel is injected into the combustion chamber when the piston position ranges from 3 degrees before the TDC position to 7 degrees after the TDC position.

[0032] In some implementations of the present technology, fuel ignition occurs when the piston is in the range from 0 to 12 degrees after the TDC position, fuel ignition occurs after fuel injection.

[0033] In some implementations of the present technology, the ignition occurs before the piston reaches the high point of the outlet in the combustion chamber of the internal combustion engine

[0034] In some implementations of the present technology, the first level of electrical power is calculated so that the EPU generates sufficient torque to rotate the crankshaft until the piston reaches a predetermined position before the TDC position; and the second level of electrical power supply is calculated so that the EPU generates sufficient torque for the piston to move past the TDC position.

[0035] In some implementations of the present technology, determining the absolute angular position of the crankshaft includes recognizing the absolute angular position of the crankshaft.

[0036] In some implementations of the present technology, the method further includes recognizing the absolute angular position of the ICE component rotating synchronously with the crankshaft, wherein the ICE component rotating synchronously with the crankshaft is selected from the EPU rotor, fuel pump, oil pump, water pump, cam shaft and balance shaft; and calculating the absolute angular position of the crankshaft based on the detected absolute angular position of the ICE component rotating synchronously with the crankshaft.

[0037] In a second aspect, the present technology provides a starting system for an internal combustion engine (ICE) having a crankshaft. The system includes a power source, an electrical rotary device (EPU), made with the possibility of installation on the crankshaft, an absolute position sensor, made with the possibility of issuing readings of the absolute angular position of the crankshaft in comparison with the angular position of the EPU rotor, and an engine control unit (ECU), functionally connected to the angle encoder. ECU is configured to determine the absolute angular position of the crankshaft according to the readings received from the absolute position sensor. The ECU is also configured to regulate the supply of electrical power from the source to the EPU at the first level for crankshaft rotation and at the second level more than at the first when the EPU rotor reaches a predetermined angular position.

[0038] In some implementations of the present technology, the ECU is also configured to: calculate the first level of electrical power supply so that the EPU generates sufficient torque to rotate the crankshaft until the rotor reaches a predetermined position; and calculating the second level of electrical power supply so that the EPU generates sufficient torque to rotate the crankshaft after the predetermined angular position of the rotor.

[0039] In some implementations of the present technology, the ECU implements the vector control of the electric power supply at the first level, taking into account the preliminary determination of sufficient torque to rotate the crankshaft until the rotor reaches a predetermined angular position; and the ECU implements the vector control of the electric power supply at the second level, taking into account the preliminary determination of sufficient torque to rotate the crankshaft of the given angular position of the rotor.

[0040] In some implementations of the present technology, the absolute angular position of the crankshaft is further related to the position of the piston in the combustion chamber of the internal combustion engine relative to the piston top dead center (TDC) position.

[0041] In some implementations of the present technology, the supply of electrical power from the source to the EPU at the second level begins when the piston reaches a predetermined position before the TDC position; The ECU is also configured to control fuel injection into the combustion chamber of the internal combustion engine when the piston passes the TDC position for the first time, and to control ignition of the fuel in the combustion chamber.

[0042] In some implementations of the present technology, the EPU is configured to be coaxially mounted on the crankshaft.

[0043] In some implementations of the present technology, the absolute position sensor is configured to sense the absolute angular position of the crankshaft.

[0044] In some implementations of the present technology, the absolute position sensor is configured to recognize the angular position of an internal combustion engine component rotating synchronously with the crankshaft, wherein the component rotating synchronously with the crankshaft is selected from the EPU rotor, fuel pump, oil pump, water pump, camshaft and balance shaft; and the ECU is configured to calculate the absolute angular position of the crankshaft based on the recognized absolute angular position of the ICE component rotating synchronously with the crankshaft and based on the mechanical relationship between the crankshaft and the ICE component rotating synchronously with the crankshaft.

[0045] In some implementations of the present technology, the absolute position sensor is permanently connected to a power source.

[0046] In some implementations of the present technology, the absolute position sensor is turned on from the power supply when starting the ICE startup procedure.

[0047] In a third aspect, the present technology provides an internal combustion engine (ICE) including a crankshaft, a first cylinder, a cylinder head connected to the first cylinder, a piston operatively connected to the crankshaft and located in the first cylinder. The first cylinder, the cylinder head, and the first piston head define a first combustion chamber with a variable volume between them. The ICE also includes an ICE starting system. The system includes a power source, an electrical rotary device (EPU), made with the possibility of installation on the crankshaft, an absolute position sensor, made with the possibility of issuing readings of the absolute angular position of the crankshaft in comparison with the angular position of the EPU rotor, and an engine control unit (ECU), functionally connected to an absolute encoder. ECU is configured to determine the absolute angular position of the crankshaft according to the readings received from the absolute position sensor. The ECU is also configured to regulate the supply of electrical power from the source to the EPU at the first level for crankshaft rotation and at the second level more than at the first when the EPU rotor reaches a predetermined angular position. The absolute angular position of the crankshaft is related to the position of the first piston in the first combustion chamber.

[0048] In some implementations of the present technology, the internal combustion engine further includes: a direct fuel injection nozzle functionally connected to the ECU; and an ignition system functionally connected to the ECU; wherein the ECU is configured to initiate fuel injection by the direct fuel injection nozzle into the first combustion chamber and initiate fuel ignition by the ignition system.

[0049] In some implementations of the present technology, the internal combustion engine further includes: a second cylinder; and a second piston operatively connected to the crankshaft and located in the second cylinder, the second cylinder, the cylinder head and the second piston head defining a second combustion chamber with a variable volume therebetween; wherein when the first piston compresses gases in the first combustion chamber, the second piston expands the volume of the second combustion chamber.

[0050] In a fourth aspect, the present technology provides a method for starting an internal combustion engine (ICE) having a crankshaft and an electric rotary device (ERA) operatively coupled to the crankshaft. The absolute position sensor, made with the possibility of issuing indications of the angular position of the EPU rotor, turns on. The EPU is supplied with current to generate enough torque to rotate the crankshaft.

[0051] In some implementations of the present technology, the absolute position sensor provides readings of the angular position of the EPU rotor in signals sent to the controller; and the controller continuously calculates the actual angular position of the EPU rotor based on the signals from the absolute encoder.

[0052] In some implementations of the present technology, supplying a current to the EPC further includes: initially supplying a first current to the EPC; and the subsequent supply of a second current to the EPU, exceeding the first, when the angular position of the EPU rotor goes beyond the given angular position.

[0053] In some implementations of the present technology, the method further includes receiving a command from the controller to start the ICE.

[0054] In some implementations of the present technology, the method further includes: determining the initial angular position of the EPU rotor; and determining a first amount of torque to be supplied from the EPU to the crankshaft based on, in particular, the initial angular position of the EPU rotor.

[0055] In some implementations of the present technology, the method further includes: determining a second angular position of the ECU rotor, the second angular position indicating that the ECU rotor has passed the first predetermined angular position; and determining a second amount of torque to be supplied from the EPC to the crankshaft based in particular on the second angular position of the EPC rotor, the second amount of torque being greater than the first amount of torque.

[0056] In some implementations of the present technology, the method further includes: determining the third angular position of the EPU rotor, the third angular position indicates that the EPU rotor has passed the second predetermined angular position, the second predetermined angular position is the position of the top dead center (TDC) of the piston at combustion chamber; and fuel injection into the combustion chamber of the internal combustion engine.

[0057] In some implementations of the present technology, the method further includes: determining the fourth angular position of the EPU rotor, the fourth angular position indicates that the EPU rotor has passed the third predetermined angular position, the third predetermined angular position follows the second predetermined position; and ignition of fuel in the combustion chamber of the internal combustion engine.

[0058] In some implementations of the present technology, the fourth angular position is less than 110 degrees of crank angle after the initial angular position.

[0059] In some implementations of the present technology, the fourth angular position is selected such that ignition occurs prior to the opening of an outlet in the combustion chamber of an internal combustion engine.

[0060] In a fifth aspect, the present technology provides an internal combustion engine (ICE) comprising a crankshaft, a cylinder head partially defining a variable combustion chamber for an internal combustion engine, a direct fuel injection nozzle mounted on the cylinder head, a power supply, an electric rotary device (EPU), made with the possibility of rotation of the crankshaft, the absolute position sensor, made with the possibility of issuing readings of the angular position of the rotor EPU, and the engine control unit (ECU), functionally connected to the absolute position sensor. The ECU is made with the possibility of vector control of the supply of electric power from the power source to the EPU taking into account the angular position of the EPU rotor and the initiation of fuel injection by the nozzle of direct fuel injection into the combustion chamber at the time selected taking into account the angular position reached by the EPU rotor.

[0061] In some implementations of the present technology, the ECU causes electrical power to be supplied from a power source to the ECU to generate a first level of torque until the ECU rotor reaches the first preset position and then generates a second level of torque exceeding the first torque level when the ECU rotor turns for the first given position.

[0062] In some implementations of the present technology, the ECU causes fuel injection by the direct fuel injection nozzle directly into the combustion chamber after the ECU reaches the first predetermined position.

[0063] In some implementations of the present technology, the absolute angular position of the ECU rotor is related to the position of the piston in the combustion chamber, with fuel injection occurring when the piston passes the top dead center position in the combustion chamber.

[0064] In some implementations of the present technology, the ECU causes the fuel to ignite after fuel injection.

[0065] In a sixth aspect, the present technology provides a method for controlling the supply of electrical power between a power supply and an electrical rotary device (EPD). A start signal is applied to the start electronic power switch to initiate the start of the electronic power switch and provide electrical power from the power source to the EPC through the start electronic power switch. The recharge signal is applied to the operational electronic power switch to initiate the operation of the operational electronic power switch and to provide electrical power from the EPU to the power source through the operational electronic power switch.

[0066] In some implementations of the present technology, the method further includes stopping the supply of a start signal to the start electronic power switch when a recharge signal is applied to the on-line electronic power switch.

[0067] In some implementations of the present technology, turning on the electronic start switch further includes periodically turning the electronic start switch on and off to restrict the supply of electrical power from the power source to the EPC.

[0068] In some implementations of the present technology, a trigger signal is periodically applied and reset to initiate periodic on and off of the electronic start switch.

[0069] In some implementations of the present technology, the trigger signal is varied in accordance with the pulse width modulation mode.

[0070] In some implementations of the present technology, the method further includes a current limiting circuit in series with an on-line electronic power switch to limit the supply of electrical power from the EPC to the power source.

[0071] In some implementations of the present technology, the method further includes, prior to sending a start signal to the electronic start-up power switch, applying and then resetting a turn-on signal to the on-line electronic power switch

[0072] In some implementations of the present technology, a start signal is supplied to the start electronic power switch via a first driver, and a recharge signal is supplied to an on-line electronic power switch via a second driver.

[0073] In a seventh aspect, the present technology provides a circuit consisting of a discharge circuit and a charge circuit. The discharge circuit includes a starting electronic power switch configured to supply electrical power from a power source to an electric rotary device (EPD) through a starting electronic power switch when the starting electronic power switch is in the ON state. The charging circuit includes an on-line electronic power switch configured to supply electrical power from the EPU to the power source through the on-line electronic power switch when the on-line electronic power switch is on.

[0074] In some implementations of the present technology, the discharge circuit further includes a first driver configured to receive a trigger signal and direct the trigger signal to the trigger electronic power switch; and the charging circuit further includes a second driver configured to receive the recharge signal and send the recharge signal to the on-line electronic power switch.

[0075] In some implementations of the present technology, the circuit further includes a control unit configured to provide a trigger signal to the first driver and to provide a recharge signal to the second driver.

[0076] In some implementations of the present technology, the control unit is also configured to terminate the supply of a start signal to the start electronic power switch when a recharge signal is applied to the on-line electronic power switch.

[0077] In some implementations of the present technology, the control unit is also configured to periodically supply and reset a trigger signal to the first driver to limit the supply of electrical power from the power source to the EPC.

[0078] In some implementations of the present technology, the control unit is also configured to vary the trigger signal in accordance with the pulse width modulation mode.

[0079] In some implementations of the present technology, the charging circuit further includes a current limiting circuit in series with the on-line electronic power switch and configured to limit the supply of electrical power from the EPC to the power source.

[0080] In some implementations of the present technology, the control unit is also configured to supply and then reset a turn-on signal to the on-line electronic power switch prior to applying a start signal to the start electronic power switch.

[0081] Additional and / or alternative features, aspects and advantages of implementations of the present technology will become apparent from the following description, accompanying drawings, and the accompanying claims.

BRIEF DESCRIPTION OF DRAWINGS

[0082] For a better understanding of the present technology, as well as other aspects and additional features thereof, reference is made to the following description, which should be used in conjunction with the accompanying drawings, where:

[0083] Figure 1 is a right side perspective view of a snowmobile;

[0084] Figure 2 is a perspective view from the front left side of the internal combustion engine of the snowmobile of Figure 1;

[0085] Figure 3A is a rear elevational view of the engine of Figure 2;

[0086] Figure 3B is a rear elevational view of another internal combustion engine that may be mounted on the snowmobile of Figure 1;

[0087] Figure 4A is a cross-sectional view of the engine of Figure 2 taken along line 4-4 in Figure 3 showing the piston at top dead center;

[0088] Figure 4B is a cross-sectional view of the engine of Figure 3B showing the piston at bottom dead center;

[0089] Figure 4C is another view of the engine of Figure 3B showing the placement of the water pump;

[0090] Figure 5 is a cross-sectional view of the engine of Figure 2 taken along line 5-5 in Figure 4A, with the MCU drive unit mounted on the engine crankshaft;

[0091] Figure 6 is a schematic diagram of the components of the engine management system of Figure 2;

[0092] Figure 7 is a block diagram of a dual strategy control system for supplying electrical power between the capacitor capacitor and the electrical rotary device (EPD) of Figure 6;

[0093] Figure 8 is a block diagram of an energy control circuit for the capacitor of Figure 6;

[0094] Figure 9 is a logical diagram of the method for starting the engine of Figure 2, in accordance with an implementation;

[0095] Figure 10 is a timing diagram showing an example of variations in engine torque resistances versus time, together with corresponding variations in engine speed;

[0096] Figure 11 is a logic diagram of the method for starting the engine of Figure 2, in accordance with another implementation;

[0097] Figure 12 is a circuit diagram showing connections between the inverter, capacitor and motor generator of Figure 6;

[0098] Figure 13 is a block diagram of a typical implementation of a vector control drive;

[0099] Figure 14 is a block diagram of an electrical system in accordance with an implementation of the present technology;

[00100] Figure 15 is a timing diagram showing an example of a sequence for changing a control strategy for supplying electrical power between a capacitor capacitor and an electric rotary device (ERA) along with corresponding variations in the motor speed;

[00101] Figure 16 is another timing diagram showing an example of the effect of control strategies on the exchange of current between the capacitor and the EPA and on the system voltage;

[00102] Figure 17 is another timing diagram showing an example of the change in torque acting on the EPC in the first control strategy;

[00103] Figure 18 is a sequence diagram showing method steps for starting an internal combustion engine; and

[00104] Figure 19 is a sequence diagram showing method steps for controlling the supply of electrical power between a power supply and an EPC.

DETAILED DESCRIPTION

[00105] A method and system for starting an internal combustion engine (ICE), as well as a method and system for starting an internal combustion engine, will be described with respect to the snowmobile 10. However, it is contemplated that the method and system can be used in other vehicles such as, but without limitation, road vehicles, off-road vehicles, motorcycle, moped, three-wheeled motor vehicle, outboard or inboard engine powered boat, and off-road vehicle (RVT). It is also contemplated that the method and system can be used in devices other than vehicles that have an internal combustion engine, such as a generator. The method and system will also be described in relation to a two-stroke, in-line, two-cylinder internal combustion engine (ICE) 24. However, it is contemplated that the method and system can be used with an internal combustion engine having one or more cylinders and, in the case of multi-cylinder engines, having in-line or other configuration such as V-engine as well as 4-stroke engines.

Vehicle

[00106] Turning now to Figure 1, the snowmobile 10 includes a front end 12 and a rear end 14, which are jointly defined in the forward direction of the snowmobile 10. The snowmobile 10 includes a frame 16 that has a tunnel 18, an engine support portion 20, and a front suspension portion 22. Tunnel 18 consists of one or more pieces of sheet metal arranged to form an inverted U-shape, which is connected at the front to the engine support part 20 and extends back from it along the longitudinal axis 23. The internal combustion engine 24 (schematically depicted in Figure 1) is mounted on the support engine parts 20 on frame 16. ICE 24 is described in more detail below. Two skis 26 are located at the front end 12 of the snowmobile 10 and are attached to the front suspension portion 22 of the frame 16 via the front suspension assembly 28. Front suspension assembly 28 includes shock absorber assemblies 29, ski struts 30, and support brackets 32. Ball joints and tie rods (not shown) functionally connect skis 26 to steering column 34. A steering device 36 is attached to the upper end of steering column 34 to provide the possibility of rotation by the drive of the racks of skis 30 and, consequently, skis 26, to control the snowmobile 10.

[00107] The endless drive track 38 is located generally under the tunnel 18 and is operatively connected to the ICE 24 via the ICE 40 (schematically shown in broken lines in Figure 1), which will be described in more detail below. The endless drive track 38 is driven around the rear suspension assembly 42 to propel the snowmobile 10 in motion. Rear suspension assembly 42 comprises a pair of slide rails 44 in sliding contact with endless drive track 38. Rear suspension assembly 42 also includes a plurality of shock absorbers 46, which may further comprise coil springs (not shown) surrounding one or more shock absorbers 46. Levers are provided. 48 and 50 suspension for attaching slide rails 44 to frame 16. Rear suspension assembly 42 also provides a plurality of parasitic wheels 52. Other types and geometries of rear suspension assemblies are also contemplated.

[00108] At the front end 12 of the snowmobile 10, the fairing 54 contains the ICE 24 and the ICE 40, thereby providing an outer skin that protects the ICE 24 and the ICE 40. The fairing 54 comprises a hood and one or more side panels that can be opened to allow access to ICE 24 and BKP 40 when necessary, for example, for inspection or maintenance of ICE 24 and / or BKP 40. Wind shield 56 is connected to fairing 54 near the front end 12 of snowmobile 10. Alternatively, wind shield 56 can be connected directly with the rudder 36. The windshield 56 acts as a windshield to reduce the air force on the driver as the snowmobile 10 moves forward.

[00109] The motorcycle-type seat 58 is located above the tunnel 18. On opposite sides of the snowmobile 10, footrests 60 are located under the seat 58 to accommodate the driver's feet.

Internal combustion engine

[00110] Turning now to Figures 2-5, ICE 24 and ICE 40 will be described. One version of ICE 24 is shown in Figures 2, 3A, 4A and 5, and another version of ICE 24 is shown in Figures 3B, 4B and 4C. In the context of the present disclosure, both versions of the ICE 24 are equivalent and interchangeable. ICE 24 operates on a two-stroke principle. ICE 24 has a crankshaft 100 that rotates about a horizontally located axis that extends generally across the longitudinal axis 23 of the snowmobile 10. The crankshaft drives the BKP 40 to transmit torque to the endless drive track 38 to drive the snowmobile 10.

[00111] BKV 40 includes a driving block 62 connected to the crankshaft 100 for rotation with the crankshaft 100, and a driven block (not shown) connected to one end of a transversely mounted transmission shaft (not shown), which is supported on the frame 16 by means of bearings ... The opposite end of the transversely mounted transmission shaft is connected to a geared drive member (not shown), and the geared drive driven member is connected to a driving axle (not shown) carrying gears (not shown) that form a drive connection with a drive track 38.

[00112] The drive unit 62 of the PCU 40 includes a pair of opposed frusto-conical belt pulleys 64 and 66 with a drive belt (not shown) in between. The drive belt is made of rubber, but it is contemplated that it could be made of metal links or polymer. The master unit 62 will be described in more detail below. The driven unit contains a pair of frusto-conical belt pulleys with a drive belt between them. The drive belt is wrapped around both the drive unit 62 and the driven unit. The torque transmitted to the driven unit provides the necessary downforce to the drive belt through its torque sensing mechanical device to efficiently transfer torque to other components in the powertrain.

[00113] As described above, drive unit 62 includes a pair of opposed frusto-conical belt pulleys 64 and 66 as can be seen in Figure 5. Both pulleys 64 and 66 rotate with crankshaft 100. Pulley 64 is axially locked relative to the crankshaft 100 and, thus, is called a fixed pulley 64. The fixed pulley 64 is also fixed without the possibility of rotation relative to the crankshaft 100. The pulley 66 can be moved forward or backward from the fixed pulley 64 in the axial direction of the crankshaft 100 to change the gear ratio of the BKP 40 and is thus called a movable pulley 66. As can be seen in Figure 5, a fixed pulley 64 is disposed between the movable pulley 66 and the ICE 24.

[00114] The fixed pulley 64 is mounted on the fixed pulley shaft 68. The fixed pulley 64 is pressed onto the fixed pulley shaft 68 such that the fixed pulley 64 rotates with the fixed pulley shaft 68. It is contemplated that the fixed pulley 64 may be coupled to the fixed pulley shaft 68 by other known means so that the fixed pulley 64 is axially and rotatable relative to the fixed pulley shaft 68. As can be seen in Figure 5, the fixed pulley shaft 68 is hollow and has a truncated hollow portion. The truncated hollow portion receives the end of the crankshaft 100 for transmitting torque from the internal combustion engine 24 to the drive unit 62. A connector 70 is inserted into the outer end (i.e., on the left side of Figure 5) of the drive unit 62, inside the shaft 68 of the fixed pulley, and is screwed into the end of the crankshaft 100 to prevent axial displacement of the fixed pulley shaft 68 relative to the crankshaft 100. It is contemplated that the fixed pulley shaft 68 may be coupled to the crankshaft 100 by other known methods so that the fixed pulley shaft 68 is axially fixed relative to the crankshaft 100. direction and without the possibility of rotation. It is also contemplated that the crankshaft 100 may be a fixed pulley shaft 68.

[00115] The cover 72 is inserted into the outer end of the shaft 68 of the fixed pulley by a tapered connection. A connector 70 is also inserted through cover 72 to connect cover 72 to fixed pulley shaft 68. It is contemplated that the cover 72 can be connected to the fixed pulley shaft 68 by other means. The radial outer portion of the cover 72 forms a ring 74. An annular rubber damper 76 is connected to a ring 74. Another ring 78 is connected to a rubber damper 76 such that a rubber damper 76 is interposed between the rings 74, 78. In the present implementation, the rubber damper 76 is vulcanized to the rings 74 , 78, but it is contemplated that they can be bonded to each other by other means, such as with an adhesive. It is also contemplated that damper 76 may be made of a material other than rubber.

[00116] The hub 80 is located around the shaft 68 of the fixed pulley and axially between the ring 78 and the movable pulley 66. The hub 80 is also fixed axially relative to the fixed pulley 64. The ring 74, the damper 76 and the ring 78 are holes (not shown) ... Connectors (not shown) are inserted through holes in ring 74, damper 76, ring 78, and hub 80 to connect ring 78 to hub 80. As a result, torque is transmitted between fixed pulley shaft 68 and hub 80 through cover 72, rubber damper 76 and ring 78. Damper 76 dampens variations in torque from fixed pulley shaft 68 resulting from ignition events in ICE 24. Thus, hub 80 rotates with fixed pulley shaft 68.

[00117] The movable pulley shaft 82 is disposed around the fixed pulley shaft 68. The movable pulley 66 is molded onto the movable pulley shaft 82 so that the movable pulley 66 rotates and moves axially with the movable pulley shaft 82. It is contemplated that the movable pulley 66 could be coupled to the movable pulley shaft 82 by other known means so that the movable pulley 66 is axially fixed relative to the shaft 82 and not rotatable. It is also contemplated that the movable pulley 66 and the movable pulley shaft 82 may be integrally formed.

[00118] To transmit torque from the hub 80 to the movable pulley 104, a torque transmission unit is provided, consisting of three roller assemblies 84 connected to the movable pulley 66. The roller assemblies 84 engage with the hub 80 so as to provide axial displacement of the movable low friction pulley 66 relative to hub 80 and to eliminate or at least minimize rotation of movable pulley 66 relative to hub 80. As described above, torque is transmitted from fixed pulley 64 to hub 80 through damper 76. Hub 80 enters engagement with roller assemblies 84 that transmit torque to movable pulley 66 with no or very little backlash. As a result, the hub 80 is considered fixed non-rotatably with respect to the movable pulley 66. It is contemplated that in some implementations the torque transmission assembly may have more or less than three roller assemblies 84.

[00119] As can be seen in Figure 5, a coiled spring pressure member 86 is disposed within a cavity 88 defined radially between the movable pulley shaft 82 and the hub 80. As movable pulley 66 and movable pulley shaft 82 move axially toward the fixed pulley 64 spring 86 is compressed. Spring 86 biases movable pulley 66 and movable pulley shaft 82 from fixed pulley 64 to their position shown in Figure 5. It is contemplated that in some implementations movable pulley 66 may be displaced from fixed pulley 64 by mechanisms other than spring 86.

[00120] The hub 80 has three arms 90 spaced 120 degrees apart. Three rollers 92 are rotatably connected to three shoulders 90 of hub 80. Three centrifugal drives 94 are pivotally coupled to three arms (not shown) formed by movable pulley 66. Each roller 92 is aligned with a corresponding one of centrifugal drives 94. Since hub 80 and movable pulley 66 are fixed non-rotatably relative to each other, rollers 92 remain aligned with their respective centrifugal drives 94 as the shafts 68, 82 rotate. The centrifugal drives 94 are spaced 120 degrees apart. The centrifugal drives 94 and roller assemblies 84 are staggered and spaced 60 degrees apart. It is contemplated that the rollers 92 could be hinged to the arms of the movable pulley 66, and that the centrifugal drives 94 could be connected to the arms 90 of the hub 80. It is also contemplated that there could be more or less than three drives 94, in which case there would be a corresponding number of arms 90 , rollers 92 and movable pulley brackets. It is also contemplated that the rollers 92 can be lowered and replaced by surfaces on which the centrifugal drives 94 can slide as they rotate.

[00121] In the present implementation, each centrifugal actuator 94 includes an arm 96 that rotates about a bridge 98 connected to its corresponding arm of a movable pulley 66. The position of the arms 96 relative to their bridges 98 may be adjustable. It is contemplated that the position of the arms 96 relative to their bridges 98 may be non-adjustable. Further details regarding centrifugal drives of the type of centrifugal drive 94 can be found in International Patent Publication WO 2013/032463 A2, published March 7, 2013, the entire contents of which are incorporated herein by reference.

[00122] The above description of the master unit 62 corresponds to one contemplated implementation of the master unit that can be used with the ICE 24. Further details regarding the master units of the type of the master unit 62 can be found in international patent publication WO 2015/151032 A1 published 8 October 2015, the entire contents of which are incorporated herein by reference. It is contemplated that other types of master blocks could be used.

[00123] ICE 24 has a crankcase 102 enclosing a portion of the crankshaft 100. As can be seen in Figures 2, 3 and 5, the crankshaft 100 protrudes from the crankcase 102. It is contemplated that the crankshaft 100 can drive a driven shaft connected directly to the end of the crankshaft 100, or offset from the crankshaft 100 and driven by means of driving, such as gears, to drive the driving block 62. It is also contemplated that the crankshaft 100 can be driven, for example by gears, a counterweight shaft enclosed in a portion of the crankcase 102, and that the drive unit 62 can be connected to the counterweight shaft, in which case the crankshaft 100 should not protrude from crankcase 102 for this purpose. The cylinder block 104 is located above the crankcase 102 and is connected to it. The cylinder block 104, as shown, defines two cylinders 106A, 106B (Figure 5). The cylinder head 108 is located above and connected to the cylinder block 104.

[00124] As best seen in Figure 5, the crankshaft 100 is supported in the crankcase 102 by bearings 110. The crankshaft 100 has two connecting rod journals 112A, 112B. In the depicted implementation, in which the two cylinders 106A, 106B are aligned, the crankpins 112A, 112B are 180 degrees apart. It is contemplated that the crankpins 112A, 112B may be at different angles from each other to accommodate other cylinder arrangements such as in a V-engine. The connecting rod 114A is connected to the connecting rod 112A at one end and to the piston 116A through the piston pin 118A at the other end. As you can see, the piston 116A has at least one ring 117A under the head and is located in the cylinder 106A. Likewise, the connecting rod 114B is connected to the connecting rod 112B at one end and to the piston 116B through the piston pin 118B at the other end. As can be seen, piston 116B has at least one ring 117B under the head and is located in cylinder 106 B. Rotation of crankshaft 100 causes pistons 116A, 116B to reciprocate within their respective cylinders 106A, 106B. Cylinder head 108, cylinder 106A, and piston head 116A define a variable volume combustion chamber 120A therebetween. Likewise, cylinder head 108, cylinder 106B, and piston head 116B define a variable volume combustion chamber 120B therebetween. It is assumed that the block 104 of cylinders can define more than two cylinders 106, in which case, the internal combustion engine 24 will be equipped with a corresponding number of pistons 116 and connecting rods 114.

[00125] Air is supplied to the crankcase 102 through a pair of air intakes 122 (only one of which is shown in Figure 4A) provided at the rear of the cylinder block 104. A pair of throttle bodies 124 are connected to a pair of air intake holes 122. Each throttle body 124 has a throttle valve 126 that can rotate to control air flow to the ICE 24. Motors (not shown) are used to change the position of the throttle valves 126, but it is assumed that throttle cables connected to the throttle arm may be used. It is also contemplated that a single motor can be used to change the position of both throttle valves 126. A pair of plate valves 128 (Figure 4A) are provided at each air intake port 122. The plate valves 128 allow air to enter the crankcase 102 but prevent air from leaving the crankcase 102 through the air intakes 122.

[00126] As the pistons 116A, 116B reciprocate, air from the crankcase 102 flows into the combustion chambers 120A, 120B through the purge holes 130. Fuel is injected into the combustion chambers 120A, 120B by direct fuel injection nozzles 132a, 132b, respectively. Direct fuel injection nozzles 132a, 132b are mounted on cylinder head 108. The direct fuel injection nozzles 132a, 132b are connected by fuel lines and / or guides (not shown) to one or more fuel pumps (not shown) that pump fuel from the fuel tank 133 (Figure 1) of the snowmobile 10. In the depicted implementation of the direct injection nozzles 132a, 132b fuel injectors are E-TEC ™ fuel injectors, however other types of direct fuel injectors are contemplated. The air / fuel mixture in the combustion chamber 120A, 120B is ignited by spark plugs 134a, 134b, respectively (not shown in Figures 2-5, but schematically shown in Figure 6). The spark plugs 134a, 134b are mounted on the cylinder head 108.

[00127] To evacuate exhaust gases resulting from combustion of the air fuel mixture in combustion chambers 120A, 120B, each cylinder 116A, 116B defines one main outlet 136A, 136B, respectively, and two auxiliary outlets 138A, 138B, respectively. It is contemplated that each cylinder 116A, 116B may have only one, two, or more than three outlets. It is also contemplated that a decompression system (not shown) may be added to the ICE 24 to provide decompression in the combustion chambers 120A, 120B when the ICE 24 is stopped. Outlets 136A, 136B (Figures 4A, 4B), 138A, 138B are connected to an exhaust manifold 140. An exhaust manifold is connected to the front of the cylinder block 104. The exhaust valves 142A, 142B mounted on the cylinder block 104 control the degree of opening of the outlets 136A, 136B, 138A, 138B. In the present implementation, the exhaust valves 142A, 142B are R.A.V.E. ™ exhaust valves, but other valve types are contemplated. It is also contemplated that the exhaust valves 142A, 142B can be omitted.

[00128] Figure 4A shows piston 116B at top dead center (TDC). Figure 4B is a cross-sectional view of the engine of Figure 3B with piston 116B at bottom dead center (BDC) to provide a better view of main outlet 136B, respectively, and secondary outlet 138B.

[00129] An electronic rotary device (EPC) is connected to the end of the crankshaft 100, which is the opposite end of the crankshaft 100, which is connected to the drive unit 62. In the present implementation, the EPC is a motor generator 144 (Figure 5), namely a motor generator 144 three-phase alternating current, such as, for example, a permanent magnet synchronous motor (PMS), an internal permanent magnet (IPM) or a surface-mounted permanent magnet (MPPM), or a variable reluctance motor (DRMS). It is contemplated that the motor generator may comprise a plurality of pole pairs generating electrical power cycling at a speed several times the rotational speed of crankshaft 100. In addition, it is contemplated that other types of motor generators could be used, including, for example , polyphase motor-generators or polyphase motor-generators. It is also contemplated that engine generator 144 may be coupled to another shaft operatively coupled to crankshaft 100 using, for example, gears or belts. Motor generator 144, as its name suggests, can function as a motor or as a generator, and can be switched between these functions. Under certain conditions, as described herein below, the engine / generator 144 is operated in an engine mode powered by either a small battery (not shown) or a capacitor 145 shown in Figure 3B.

[00130] A battery that is smaller and lighter than that typically used for cold starting ICE 24 can be used for the electric start procedure and / or for the auxiliary start procedure, which will be described later herein. Alternatively, the electrical start procedure and / or the auxiliary start procedure can be based on the use of capacitor capacitor 145. Non-limiting examples of capacitor capacitors include a high capacitor, an ultracapacitor (U-CAP), an electric double layer capacitor, and a supercapacitor. A small battery or capacitor bank 145 supplies electrical power to the motor generator 144 to rotate the crankshaft 100. The capacitor bank 145 can store relatively large amounts of energy. In at least one implementation, capacitor 145 includes a plurality of capacitors in series, each capacitor in the series optionally contains multiple capacitors in parallel so that capacitor 145 can withstand voltages generally within the operating voltage range of the injectors 132A, 132V directly fuel injection. In the context of the present disclosure, reference is made to the capacitor 145 as a single unit. Without limitation and for reasons of brevity, implementations in which the electrical start procedure or the auxiliary start procedure, or both, are implemented with the capacitor 145, together with the motor generator 144 will be described herein below.

[00131] When functioning as a generator, engine generator 144 is rotated by crankshaft 100 and generates electricity that is supplied to capacitor 145 and other electrical components of ICE 24 and snowmobile 10. Exchange of electrical power between capacitor 145 and engine generator 144 occurs through an electrical converter. In implementations in which the motor generator 144 is a three phase motor, the electrical converter is a three phase inverter 146. It is also contemplated to use a polyphase or polyphase inverter in conjunction with a polyphase or polyphase motor generator. The control strategies of the motor generator 144, applicable to its cranking and current generation functions, and the effect of these strategies on capacitor 145 and inverter 146, are described herein below.

[00132] As can be seen in Figure 5, engine generator 144 has a stator 148 and a rotor 150. Stator 148 is positioned around crankshaft 100 outside crankcase 102 and attached to crankcase 102. Rotor 150 is keyed to the end of crankshaft 100 and partially encloses stator 148. Housing 152 is positioned above engine generator 144 and coupled to crankcase 102. Lining 154 is coupled to end of housing 152.

[00133] Three starting procedures for the snowmobile 10 may be available to the user. The first procedure comprises a manual starting procedure that is based on the use of a reversing starter 156. The second start-up procedure contains the electrical start-up procedure. The third startup routine contains the auxiliary startup routine. One or both of the electric and auxiliary starting procedures may be present in any implementation of the snowmobile 10. Next, the second and third starting procedures will be described below. As can be seen in Figure 5, the recoil starter 156 is housed within the space defined by the housing 152 and the pad 154 between the pad 154 and the engine generator 144. The recoil starter 156 has a cord 158 wound around a coil 160. A ratchet 162 selectively connects the coil 160 with rotor 150. To start the internal combustion engine 24 with the recoil starter 156 during the manual start procedure, the user pulls on the handle 163 (Figure 3A) connected to the end of the cord 158. This rotates the spool 160 in a direction that causes the ratchet 162 to lock. thereby turning the rotor 150 and the crankshaft 100. Rotation of the crankshaft 100 causes the pistons 116A, 116B to reciprocate, which enables fuel injection and ignition, thereby starting the ICE 24. When the ICE 24 is started, the rotation of the crankshaft 100 with respect to the coil 160 disengages the ratchet 162 and, as a result, crankshaft 100 does not rotate spool 160. When the user releases the handle, a spring (not shown) rotates spool 160, thereby winding cord 158 around spool 160.

[00134] In the present implementation, both the drive unit 62 and the engine generator 144 are mounted on the crankshaft 100. It is contemplated that both the drive unit 62 and the engine generator 144 can be mounted on a shaft other than the crankshaft 100 such as, for example, a counterweight shaft. In the present implementation, the drive unit 62, the engine generator 144, and the recoil starter 56 all rotate about and are coaxial with the axis of rotation of the crankshaft 100. It is contemplated that the drive unit 62, engine generator 144, and recoil starter 56 can all rotate about and are coaxial with a shaft other than crankshaft 100, such as, for example, a counterweight shaft. It is also contemplated that at least one of the drive unit 62, the motor generator 144, and the retrace starter 56 can rotate about a different axis. In the present implementation, the drive unit 62 is located on one side of the internal combustion engine 24, and both the engine generator 144 and the reverse starter 56 are located on the other side of the internal combustion engine 24. It is assumed that the engine generator and / or the reverse starter 56 can be located on the same side of the ICE 24 as the master block 62.

Internal combustion engine control system

[00135] Available starting procedures for the snowmobile 10 include an electric starting procedure, an auxiliary starting procedure, and a manual starting procedure. Figure 6 is a schematic diagram of the components of the engine management system of Figure 2. Control of the components used to start the ICE 24 in the electric start procedure and in the auxiliary start procedure is performed by an engine control unit (ECU) 164 mounted on the ICE 24, as shown in the Figures. 3B and 4B. The auxiliary start-up procedure will be explained below. ECU 164 is also used to control the operation of the ICE 24 after it has been started. ECU 164 is powered by capacitor 145 as will be described later herein. ECU 164 is depicted as one physical unit (further shown in Figure 14) containing one processor (also in Figure 14), for example, one microcontroller. Other configurations are within the scope of this disclosure. For example, it is contemplated that the features of ECU 164 may be implemented using multiple coprocessors, such as two or more microcontrollers. It is also contemplated that the various tasks of the ECU 164 may be shared between two or more microprocessors integrated into one electronic module, or two or more microprocessors distributed across different electronic modules. As a non-limiting example, one electronic module may comprise a first processor configured to control the supply of electrical power from motor generator 144 to capacitor 145 and to control supply of electrical power from capacitor 145 to motor generator 144, and a second processor configured with the ability to control the fuel injection function and the ICE ignition function. To initiate an electrical start procedure or an auxiliary start procedure for ICE 24, ECU 164 receives input from components located to the left of ECU 164 in Figure 6, some of which are optional and not present in all implementations, as will be described below. Using this input, ECU 164 receives information from control cards 166 as to how the components located to the right of ECU 164 in Figure 6 should be controlled to start ICE 24. Control cards 166 are stored in an electronic storage device such as Electrically erasable programmable read only memory (EEPROM) or flash drive. It is contemplated that instead of or in addition to control cards 166, ECU 164 may use control algorithms to control components located to the right of ECU 164 in Figure 6. In the present implementation, ECU 164 is connected to various components of Figure 6 via wired connections; however, it is contemplated that it can be wirelessly connected to one or more of these components.

[00136] A user-activated electric start switch 168 provided with the snowmobile 10, such as a command button mounted on or near the steering wheel 36, sends a signal to the ECU 164 that the user wishes to start the ICE 24 when it is activated. The electrical start switch 168 may also be a key operated switch, sensor, or any other type of device with which the user can provide input to ECU 164 that the ICE 24 is to be started. In at least one implementation, the electrical start switch 168 may be a sensor operatively coupled to the cord 158 of the retrace starter 156 and to the ECU 164. Some thrust, such as a simple tugging on the cord 158 by the operator, may be detected by this sensor, resulting in initiation of the procedure for the electric start of the internal combustion engine 24, provided that all the conditions for the electric start procedure are present.

[00137] The crankshaft position sensor (DPKV) 171 and the absolute crankshaft position sensor (ADPKV) 170 are located adjacent to the crankshaft 100 to recognize the absolute position of the crankshaft 100. The DPKV 170 readings are used by the ECU 164 to determine the crankshaft speed 170. B As a result of manual start or auxiliary start, DPKV 170 is switched on from the initial rotation of the crankshaft 100. Similarly to the ECU 164, the DPKV 170 is switched on from the capacitor tank 145. In one implementation, the DPKV 170 is electrically connected to the capacitor capacitor 145 in such a way that the DPKV 170 is constantly in the on state as long as there is a minimum charge level in the capacitor capacitor 145. In another implementation, DAPKV 170 is turned on from capacitor 145 through ECU 164 during a start-up procedure, as will be described later herein. In the present implementation, the DPKV 171 is an inductive position sensor and the DPKV 170 is a Hall effect sin / cos encoder. Figure 5 shows an example of a Hall effect placement of DAPKV 170, which is located at an extreme point of the crankshaft 100 and rotates the crankshaft 100. Alternatively, the DAPKV 170 may include an optical sensor. Figure 5 also shows DPKV 171, the location of which allows it to track the movement of the rotor 150 of the engine generator 144, and the rotor 150 rotates synchronously and at the same speed as the crankshaft 100. The DPKV 170 recognizes the absolute position of the crankshaft 100 in a continuous mode as long as the DAPKV 170 is powered by an electrical power source (shown in the further Figures). The DAPKV 170 sends a signal indicative of the absolute position of the crankshaft 100 to the ECU 164. The absolute position of the crankshaft 100, provided by the DAPKV 170, allows the ECU 164 to determine the current position of the pistons 116A, 116B, regardless of whether the crankshaft 100 is rotating or stopped. in any position. In particular, ECU 164 uses the provided absolute position information to determine the current position of pistons 116A, 116B with respect to their respective top dead center (TDC) positions. The current position of the piston in relation to its TDC position can be expressed in degrees of rotation before TDC (TDC) or after TDC (TDC). Taking into account changes in the absolute position of the crankshaft 100 obtained from the DAPKV 170, the ECU 164 can also determine the rotational speed of the crankshaft 100.

[00138] It is contemplated that an absolute position sensor (not shown) can further determine the absolute position of a component of the ICE 24 other than the crankshaft 100 that rotates in synchronization with the crankshaft 100, such as a water pump. Figure 4C is another view of the engine of Figure 2 showing the placement of a water pump, generally 173. In an implementation, the water pump 173 rotates at the same speed as the crankshaft 100. A magnet 175 is mounted on the water pump 173. The sensor 177 is on the Hall effect is in a fixed position and monitors the rotational movements of the magnet 175 when the rotation of the crankshaft 100 causes the water pump 173 to rotate. Other components of the ICE 24 on which the absolute position sensor may be mounted include, for example and without limitation, the rotor 150 the engine -generator 144, fuel pump, oil pump, camshaft (if the internal combustion engine is a 4-stroke engine), balance shaft (not shown), and the like. In this case, based on the mechanical configuration of the internal combustion engine 24, ECU 164 can establish the absolute position of the crankshaft 100 from the absolute position of this component.

[00139] ECU 164 controls the operation and timing of the direct injection injectors 132a, 132b and spark plugs 134a, 134b. To this end, when starting the internal combustion engine 24, the ECU 164 uses the absolute position of the crankshaft 100 obtained from the DAPKV 170 to initiate the injection of the calculated amount of fuel by the direct fuel injection nozzles 132a, 132b into the respective combustion chambers 120A, 120B shortly after the pistons 116A, 116B reached TDC positions. The ECU 164 then causes the fuel to ignite the respective spark plugs 134a, 134b immediately thereafter. For example and without limitation, injection into combustion chamber 120A may occur if crankshaft 100 rotates before piston 116A reaches a position in the range of about 3 degrees before TDC to 7 degrees after TDC. Ignition then occurs using a spark plug 134 in combustion chamber 1220A, for example in the range of about 0 to 12 degrees after TDC (0-12 degrees TDC) for piston 116A. The injection and ignition times may vary depending on the operating conditions of the internal combustion engine 24.

[00140] The auxiliary start procedure can be initiated provided that the conditions described below are met when rotation of the crankshaft 100 is initiated by a user pulling on the retrace starter cord 158 156. After the initial rotation of the crankshaft 100, the DPKV 171 activates the ECU 164. In turn, the ECU 164 initiates the excitation of the DAPKV 170 with a capacitor capacitor 145, which allows the DPKV 170 to transmit information about the absolute angular position of the crankshaft 100 to the ECU 164.

[00141] Voltage sensor 167, such as a voltmeter, provides voltage measurements of capacitor 145 to ECU 164. As explained in more detail herein below, ECU 164 uses this voltage measurement to determine if there is enough energy in capacitor 145 to start the ICE. 24 using the electric start procedure or to assist with the auxiliary start procedure.

[00142] In some cases, other sensors may be used to determine whether the engine can be started by an electrical start procedure or an auxiliary start procedure, as explained later in this document. These optional sensors include, for example, an engine temperature sensor 172, an air temperature sensor 174, an atmospheric air pressure sensor 176, an exhaust gas temperature sensor 178, a timer 180, and an ECU temperature sensor 182.

[00143] An engine temperature sensor 172 is mounted to the ICE 24 to detect the temperature of one or more of the crankcase 102, the cylinder block 104, the cylinder head 108, and the temperature of the engine coolant. Engine temperature sensor 172 sends a signal indicative of the detected temperature to ECU 164.

[00144] An air temperature sensor 174 is mounted on the snowmobile 10, such as an air intake system, to detect the temperature of the air supplied to the internal combustion engine 24. The air temperature sensor 174 sends a signal indicative of the air temperature to the ECU 164.

[00145] An atmospheric air pressure sensor 176 is mounted on the snowmobile 10, for example in an air intake system, to detect atmospheric air pressure. The atmospheric air pressure sensor 176 sends a signal indicative of the atmospheric air pressure to the ECU 164.

[00146] An exhaust gas temperature sensor 178 is mounted on the exhaust manifold 140 or other part of the exhaust system of the snowmobile 10 to detect the temperature of the exhaust gases. The exhaust gas temperature sensor 178 sends a signal indicative of the exhaust gas temperature to the ECU 164.

[00147] Timer 180 is coupled to ECU 164 to provide information regarding the amount of time elapsed since ICE 24 stopped to ECU 164. Timer 180 may be an active timer that starts when ICE 24 stops. Alternatively, the timer function 180 can be derived from the calendar and clock function of the ECU 164 or other electronic component. In such an implementation, ECU 164 logs the time and date when the ICE 24 was stopped, and searches for this data to determine how much time has passed since the ICE 24 was stopped, when ECU 164 receives a signal from the electric start switch 168 that the user wants to start the internal combustion engine 24.

[00148] ECU temperature sensor 182 is mounted on a physical module (not shown) that contains one or more processors (not shown) configured to implement ECU 164 functions. ECU temperature sensor 182 sends a signal indicative of the temperature of this module, on BUD 164.

[00149] It is contemplated that one or more sensors 172, 174, 176, 178, 182 and timer 180 may be omitted. It is also contemplated that one or more of the sensors 172, 174, 176, 178, 180, 182 and the timer 180 may only be used under certain conditions. For example, the exhaust gas temperature and pressure sensors 178, 180 can only be used when the internal combustion engine 24 has recently been shut down, in which case some of the exhaust gases will still be present in the exhaust system, or after the first ignition of the air-fuel mixture in one or more chambers. 120A, 120B combustion.

[00150] ECU 164 uses input received from at least some of electrical start switch 168, sensors 167, 170, 171, 172, 174, 176, 178, 182, and timer 180 to retrieve one or more corresponding cards 166 control and to control the engine generator 144, direct fuel injectors 132a, 132b and ignition plugs 134a, 134b using these inputs and / or control cards 166 to start the internal combustion engine 24, depending on the situation. Input data and control cards 166 are also used to control the operation of the ICE 24 immediately after it has been started. Although not shown in Figure 6 for ease of illustration, various components of the control system in Figure 6 are powered from capacitor 145.

[00151] ECU 164 is also coupled to a display 186 provided with the snowmobile 10 near the rudder 36 to provide information to the user of the snowmobile 10 such as, for example, engine speed, vehicle speed, oil temperature, and fuel level.

[00152] Turning now to Figure 7, details of the electronic system for the electrical and auxiliary starting procedures of the ICE 24 will be described. Figure 7 is a block diagram of a control system with two strategies for supplying electrical power between the capacitor capacitor and the ECU of Figure 6. Some components included in the above description of FIG. 6 are reproduced in FIG. 7 for a more detailed representation of their operation.

[00153] The supply of electrical power between the capacitor capacitor 145 and the motor-generator 144 occurs through the inverter 146. ECU 164 includes or is otherwise operatively connected to a strategy switch 184 that is configured to change the control strategy to supply electrical power between the capacitor capacitor 145 and the motor a generator 144 between at least two (2) different control strategies. ECU 164 controls inverter 146 via strategy switch 184.

[00154] To start the ICE 24 using an electronic start procedure, the user of the snowmobile 10 enters input data into the electric start switch 168, for example, by pressing a command button. BUD 164 is informed about this command. In response, ECU 164 may control the supply of electrical power from capacitor 145 to engine generator 144 based on a predetermined torque value, or a request for sufficient torque to drive crankshaft 100 to start ICE 24. In an embodiment, ECU 164 may determine torque request. The determination of the torque demand is carried out considering that the ICE 24 is expected to have a torque resistance with a high degree of non-uniformity; alternatively, instead of detecting a torque demand, ECU 164 may determine a speed demand applied to crankshaft 100 to control the amount of power that engine generator 144 must supply to crankshaft 100 to start ICE 24. Capacitor voltage 145 is sensed by a sensor 167 voltage and is output to ECU 164. If this voltage is below the threshold value V _MinE of the electric start voltage, which is the minimum voltage of capacitor 145 for the electrical start procedure, ECU 164 determines that capacitor 145 does not have enough energy to issue a torque request or requesting a speed sufficient to start the ICE 24 using the electric start procedure. Consequently, ECU 164 does not permit ICE 24 to start using the electrical start procedure and activates display 186 to display a "manual start" indication or an "auxiliary start" indication in implementations where this option is available. Generally speaking, the threshold value V _MinE of the electrical start voltage is based on determining that capacitor 145 is sufficiently _{charged to} ensure a successful electrical start procedure under most operating conditions. If this minimum voltage threshold for the electrical start procedure is met, ECU 164 activates the supply of electrical power from capacitor 145 to motor generator 144 through inverter 146 in the first control strategy, initiating rotation of crankshaft 100. ECU 164 also drives direct injection injectors fuel 132a and 132b to directly inject fuel into combustion chambers 120A, 120B, and actuates spark plugs 134a and 134b to ignite fuel in combustion chambers 120A, 120B. As indicated herein above, the ICE 24 may comprise one or more cylinders and the two (2) combustion chambers 120A and 120B are indicated for illustrative purposes only. If these operations are successful, the rotation of the crankshaft 100 reaches the minimum rotation threshold corresponding to the successful start of the internal combustion engine 24. Thereafter, when the speed of the crankshaft 100 is equal to or higher than the minimum rotation threshold, ECU 164 controls the supply of electrical power from the engine generator 144 to the capacitor capacitance 145 is still through inverter 146 to activate charging of capacitor capacitor 145. Power supply from motor generator 144 to capacitor capacitor 145 is generally performed in a second control strategy different from the first control strategy. It is also contemplated in which the supply of electrical power from the engine generator 144 to the capacitor 145 is performed in the first control strategy at low speeds of rotation of the crankshaft 100 or at low braking requirements and in the second control strategy at high speeds of rotation of the crankshaft 100.

[00155] The current sensor 188 can be used to optimize the current consumption of the capacitor 145 and optimize its energy use. The current sensor 188 provides an indication of the energy from the capacitor 145 consumed during the electrical start-up procedure to the ECU 164. In an implementation, current sensor 188 comprises a combination of phase current sensors (not explicitly shown) provided on two (2) phases of motor generator 144. Encoding measurements from these two (2) phase current sensors provides a reliable estimate of the current flowing between capacitor capacitor 145 and motor generator 144. As shown in FIG. 13, current measurements can be obtained across all three (3) phases of motor generator 144. Alternatively, the energy use of capacitor 145 can be optimized without current sensors, for example an open loop approach having a predetermined torque demand pattern used by ECU 164 to activate all cranking sequences. It is also possible to optimize the energy use of the capacitor 145 based on a speed request with reliably tuned controllers or based on a predetermined pattern of multi-step speed requests.

[00156] The electric start of the ICE 24 may fail even if the preconditions for the electric start procedure were initially present. For example, this can happen if, while energizing the capacitor 145 to the motor generator 144, the voltage sensor 167 detects that the voltage of the capacitor 145 falls below the residual voltage threshold V _MinR , which is below the _starting voltage threshold V _MinE . before the speed of rotation of the crankshaft 100 reaches the minimum rotation threshold corresponding to the successful start of the internal combustion engine 24. Under these conditions, the ECU 164 stops supplying power from the capacitor 145 to the engine generator 144 and operates the display 186 to provide an indication of manual start or auxiliary trigger indications in implementations where this option is available. Generally speaking, the residual voltage threshold V _MinR corresponds to the minimum charge on capacitor 145, which is expected to be sufficient to allow fuel to be injected into combustion chambers 120A, 120B and ignited while crankshaft 100 continues to rotate.

[00157] To start the internal combustion engine 24 using the auxiliary start procedure, the user of the snowmobile 10 pulls on the retraction starter cord 158 156, initiating rotation of the crankshaft 100. After the initial rotation of the crankshaft 100, DPKV 171 activates the ECU 164, and then DAPKV 170 transmits to the ECU 164 information about the absolute angular position of the crankshaft 100. In response, ECU 164 can control the supply of electrical power from capacitor 145 to engine generator 144 to assist in driving crankshaft 100 in rotation to start internal combustion engine 24. In some cases, the voltage of capacitor 145 is detected by a sensor 167 voltage and output to ECU 164. In this case, if this voltage is below the threshold value V _MinA of the auxiliary start voltage, which is the minimum voltage of capacitor 145 for the auxiliary start procedure, ECU 164 determines that capacitor 145 does not have enough energy to promoting launch ICE 24, and ECU 164 prevents ICE 24 from being started by the auxiliary start procedure, instead activating display 186 to display a "manual start" indication. Generally speaking, the auxiliary trigger voltage threshold V _MinA is based on determining that capacitor 145 is sufficiently _charged to enable a successful auxiliary trigger procedure under predetermined operating conditions. In implementations in which both electrical start and auxiliary start procedures are present, the threshold value V _MinA of the auxiliary start voltage is lower than the threshold value V _MinE of the electric start voltage. If this minimum voltage threshold for the auxiliary start procedure is met, ECU 164 activates the supply of electrical power from capacitor 145 to motor generator 144 via inverter 146 in the first control strategy, assisting crankshaft 100 to rotate. ECU 164 also drives direct injection injectors fuel 132a and 132b to directly inject fuel into combustion chambers 120A, 120B, and actuates spark plugs 134a and 134b to ignite fuel in combustion chambers 120A, 120B. As indicated herein above, the ICE 24 may comprise one or more cylinders and the two (2) combustion chambers 120A and 120B are indicated for illustrative purposes only. If these operations are successful, the rotation of the crankshaft 100 reaches the minimum rotation threshold corresponding to the successful start of the ICE 24. The ICE 24 then operates as explained in the above description of the electrical start procedure.

[00158] Figure 8 is a block diagram of an energy control circuit for capacitor 145 of Figure 6. Circuit 200 shows how the DPKV 171, ECU 164, and capacitor 145 are electrically connected in an implementation. and ECU 164 is operated by an electric start switch 168, which is shown as a button. In the case of the auxiliary start procedure and in the case of the manual start procedure, the connection is made by the signal from the DPKV 171 present at the start of rotation of the crankshaft 100. The capacitor capacitor 145 is shown as a sum of the smaller capacitors 202 connected in series. As previously indicated, each of these smaller capacitors 202 may actually be composed of a plurality of capacitors connected in parallel. Each of the smaller capacitors 202 can withstand a relatively low voltage applied to it. The capacitor capacitance 145 formed by the series sum of the smaller capacitors 202 can handle the rated voltage of the circuit 200, which is also the rated voltage of the electrical systems of the snowmobile 10, with the addition of a safety factor for sudden overvoltage.

[00159] Circuit 200 provides an output voltage between lead 208 and ground 210 when circuit 200 is active. When circuit 200 is inactive, capacitor 145 is disconnected from ground 210 via power electronic switches, such as metal oxide semiconductor (MOS) transistors Q1 and Q2, which are turned off at the time and therefore open the circuit. It is also contemplated to replace the MOSFETs Q1 and Q2 with a bipolar transistor, such as an IGBT (IGBT). The available voltage of capacitor 145 is detected between terminals 208 and 210, which are electrically connected to the voltage sensor 167 shown in the previous Figures.

[00160] Capacitor C1, shown in Figures 3B and 4B and schematically represented in Figure 8, is located between lead 208 and ground 210. The role of capacitor C1 is to filter voltage variations from capacitor 145 in favor of various electrical components of snowmobile 10, including, for example, direct injection injectors 132a and 132b, headlights, and the like. In some implementations, the capacitor C1 may be omitted. The voltage between lead 208 and ground 210, which is the system voltage for snowmobile 10, is approximately the same as the rated voltage of capacitor 145, although operating voltages between different system states may not be constant at all times.

[00161] When the ICE 24 has been stopped for a long time, for example, more than several hours, the voltage across the capacitor 145 falls below the electric start voltage threshold V _MinE and below the auxiliary start threshold V _MinA , and circuit 200 is not energized. Thus, starting the ICE 24 requires recourse to the manual start procedure. When the internal combustion engine 24 has been stopped for a relatively short time, the duration of which largely depends on the capacity for energy storage of the capacitor capacitor 145, the voltage across the capacitor capacitor 145 may be equal to or higher than the threshold value V _MinE of the electric start voltage, in which case the electric launch. If the voltage of the capacitor 145 is less than the threshold value V _MinE of the electric start voltage but is at least equal to or greater than the threshold value V _{MinA of the} auxiliary start, an auxiliary start procedure may be available. The auxiliary startup procedure is described in more detail later in this document.

[00162] When the voltage of the capacitor 145 is at least equal to or greater than the threshold value V _MinE of the electric start voltage, pressing the electric start switch 168 (command button) by the user activates the electric start procedure. This user action is detected by the start command detector 212 of the ECU 164. When the user starts the manual start procedure or the auxiliary start procedure, the DPKV 171 turns on and sends an on signal to the start command detector 212.

[00163] Start command detector 212 activates ECU 164. At the same time, electrical power is supplied from capacitor 145 to ECU 164. Depending on specific implementations, start command detector 212 may receive a simple short electrical contact provided by electrical start switch 168. to initiate the electrical start procedure. Alternatively, the start command detector 212 may require holding down the electric start switch 168 for several seconds. Upon detecting an electrical start command or an enable signal, the start command detector 212 sends a signal to the wake-up circuit 214 of the ECU 164. The wake-up circuit 214 controls the following operations.

[00164] Initially, the wake-up circuit 214 provides an on signal 220 to the driver 216 of the transistor Q1, which is an on-line electronic power switch. The driver 216 then applies an on signal to the transistor Q1, which turns on the transistor Q1 and allows the capacitor 145 to start charging the capacitor C1 through the current limiting circuit 224. As soon as the voltage in the capacitor C1 begins to establish a voltage, the wake-up circuit 214 interrupts the on signal 220 and provides a start signal 221 to the driver 217 of the transistor Q2, which is an electronic start-up power switch, which effectively turns the capacitor capacitor 145 in parallel with the capacitor C1 to further charge the capacitor C1. ... In an implementation, wake-up circuit 214 controls driver 217 to repeatedly turn on and off transistor Q2 at high frequency to prevent excess current from flowing from capacitor 145 to capacitor C1. For example, the wake-up circuit 216 of the ECU 164 may vary the trigger signal 221 in accordance with a pulse width modulation (PWM) mode. The electrical conductance through transistor Q2 can be controlled initially with a small load cycle increasing with decreasing voltage difference between capacitor C1 and capacitor 145. Regardless, capacitor C1 is rapidly charged to reach the voltage of capacitor 145. As a result of this equalization, the voltage of capacitor 145 may decrease slightly, but this effect is limited by the fact that C1 is much smaller than capacitor 145. After C1 is charged, an electrical connection is established between lead 208 and sensors 167, 170, 171, 172, 174, 176 and 182, timer 180 and other components of the snowmobile 10, which may turn on at the same time or later, depending on the needs of the application.

[00165] In an implementation where C1 is not present, the wake-up circuit 214 may not supply the enable signal 220 to the driver 216. In this case, in response to the signal from the start command detector 212, the wake-up circuit 214 simply provides a trigger signal 221 to the driver 217 of the transistor Q2 so that the voltage of capacitor 145 becomes available at lead 208.

[00166] In an implementation where the DAPKV 170 is not permanently connected to the capacitor 145, it is turned on at the start of the start procedure by tapping 208 after equalizing the voltage so that the current (ie initial) absolute angular position of the crankshaft can be read. This reading is transmitted from DAPKV 170 to ECU 164. Electrical starting then continues with ECU 164 controlling the supply of power from capacitor 145 to motor generator 144 via lead 208, which is connected to inverter 146 in one of the ways described in relation to the following Figures. ECU 164 can drive transistor Q2 in PWM mode to limit the supply of electrical power from capacitor 145 to motor generator 144.

[00167] After the electrical start procedure is successfully completed, when the ICE 24 is idling, engine generator 144 may initially have a limited power generation capacity. The accessories of the snowmobile 10, including, for example, direct injection injectors 132a and 132b and headlights, require a certain amount of power. For the functioning of the vehicle, it is more important to power these accessories than to recharge the capacitor 145. In order to prevent an excessive voltage drop of the capacitor C1, at the outlet 208 during idle or during the operation of the internal combustion engine 24, the ECU 164 in some cases can control the driver 217 for turning off the transistor Q2 until the crankshaft 100 rotates at a speed greater than a predetermined rotation threshold.

[00168] After the ICE 24 reaches a sufficient number of revolutions, and the voltage at the lead 208 becomes sufficient, the ECU 164 stops the supply of the start signal 221 to the driver 217, which leads to the disconnection (opening) of the transistor Q2. ECU 164 also sends a recharge signal 222 to driver 216 of transistor Q1. Driver 216 then provides a recharge signal to Q1, which turns on (short) Q1. Transistor Q1 is in series with current limiting circuit 224. Transistor Q1 effectively creates contact between capacitor 145 and capacitor C1, while current limiting circuit 224 regulates the charging rate of capacitor 145 taking into account the presence of electrical power at any speed of internal combustion engine 24. In the implementation, current limiting circuit 224 includes a resistor or inductor (not shown).

[00169] In another implementation, circuit 200 includes one driver 217 and one transistor Q2 and does not include a current limiting circuit. The wake-up circuit 214 periodically applies a start signal 221 to the driver 217 of the transistor Q2, for example, in accordance with the PWM mode, so that the voltage at the lead 208 gradually increases until it becomes practically equal to the voltage of the capacitor 145. In the same implementation, the signal 222 recharge is also supplied to driver 216 of transistor Q2. Instead of using the current limiting circuit 224 to control the charging rate of the capacitor 145, the recharge signal 222 may also be supplied to the driver 217 in accordance with the PWM mode. As will be shown later herein, a strategy for controlling the supply of electrical power from motor generator 144 to capacitor 145 can alternatively be used to control the charging rate of capacitor 145.

[00170] In some cases, ECU 164 may integrate an automatic shutdown circuit that can interrupt all electrical functions of the snowmobile 10 in the event of a system failure.

[00171] Table I shows a sequence of events containing a manual start procedure for the ICE 24 followed by an electrical start procedure command received after a waiting time that does not exceed the system's electrical start capacity. In Table I, “PWM” denotes “pulse width modulation,” a technique that can in some cases be used in the first and second strategies to control the supply of electrical power between capacitor 145 and motor generator 144, as shown herein below.

[00172] In Table I, the expression “idle or engine running” means that the internal combustion engine 24 is started and operates on its own, without the application of torque by the engine generator 144 or by using the reverse starter 156.

[00173] In at least one implementation, both voltage thresholds V _MinE and V _MinR may be determined within the operating voltage range of the direct fuel injection injectors 132a and 132b such that if the voltage of the capacitor 145 is insufficient to inject fuel by the injectors 132a and 132b direct fuel injection into cylinders 106A, 106B, no electrical start procedure is attempted or aborted if it fails.

Electric start procedure

[00174] Figure 9 is a logical diagram of the method for starting the engine of Figure 2, in accordance with an implementation. The sequence shown in Figure 9 contains many operations, some of which may be performed in a variable order, some operations may be performed concurrently, and some operations are optional. The method begins at step 300 when the internal combustion engine 24 of the snowmobile 10 is stopped. The voltage of the capacitor 145 is measured by the voltage sensor 167 in step 302. In the same step 302, the display 186 may indicate "auto start" if the voltage meets or exceeds the threshold value V _MinE of the electric start voltage and if other conditions for the electric start procedure described in of this document below are complied with. The user activates the electrical start switch 168, which is detected by the start command detector 212 in step 304. In step 322, in response to the electrical start request detection, the ECU 164 controls the drivers 216 and 217 of the transistors Q1 and Q2 to allow the capacitor 145 to charge the capacitor C1 before equalization their voltage values. ECU 164 and various sensors, including, in particular, DAPKV 170, are switched on from the capacitor capacitor 145 as a result of this voltage equalization. Then, in step 306, ECU 164 performs a comparison between the capacitor voltage 145 and the electric start voltage threshold V _MinE to determine whether it is possible to initiate the electric start procedure for the ICE 24. If it is determined that the capacitor voltage 145 is below the electric start voltage threshold V _MinE start, the electric start procedure is prevented. Otherwise, at step 308, it is verified that the engine temperature measured by the engine temperature sensor 172 meets or exceeds the engine temperature threshold Th0. The electrical start procedure is prevented if this threshold for engine temperature is not met. Otherwise, at step 310, it is verified that the ECU temperature sensor 182 outputs a ECU temperature reading 164 that matches or exceeds the ECU temperature threshold Th1. The electrical start procedure is prevented if this ECU temperature threshold is not met. There may be additional steps related to using measurements from other sensors included in the above description of Figure 6. These measurements may be output to ECU 164 by air temperature sensor 174, atmospheric temperature sensor 176, or timer 180. ECU 164 may be performed additional tests based on these measurements to determine the likelihood that the electrical start procedure will be successful or not, or to determine the amount of torque sufficient to drive the crankshaft 100 into rotation. For example, the electrical start procedure may be made dependent, in ECU 164, on a timer 180 informing ECU 164 that the time period since the ICE 24 is stopped is below a predetermined time value when the user activates the electrical start switch 168 in step 304. Based on the time period from the moment the internal combustion engine 24 stops, it is possible to estimate whether the voltage of the capacitor capacitor 145 will fall below the threshold value V _MinE of the electric start voltage, knowing the maximum charge voltage of the capacitor capacitor 145 from the previous sequence of starting the internal combustion engine 24, and based on the typical leakage of capacitor energy. containers 145.

[00175] Regardless of whether the electrical start procedure is prevented because the voltage of the capacitor 145 is not sufficient (step 306), because the motor temperature is too low (step 308), because the ECU temperature is too low (step 310), the method proceeds to step 312. At step 312, ECU 164 activates display 186 to display "Manual Start" or some other message indicating to the user of the snowmobile 10 to manually start the snowmobile 10 using the reversing starter 156 (i.e. pull rod 163). In implementations where an auxiliary trigger procedure is available, display 186 may instead display "Auxiliary trigger" or some other similar message, provided current conditions permit the use of the procedure. The display of a manual start indication or an auxiliary start indication at operation 312 may be followed by any decision made by the ECU 164 to refuse to proceed to the electric start procedure. It is contemplated that instead of displaying a message on display 186, ECU 164 may activate an audible beep or provide some other type of feedback to a user of snowmobile 10 indicating that snowmobile 10 must be manually started using reversal starter 156. A manual start procedure or an auxiliary start procedure may be initiated when a user pulls on the cord 158 of the recoil starter 156. If the conditions for the Auxiliary Startup Procedure are met, this procedure can be initiated as described below in this document. Otherwise, when the conditions for the auxiliary start procedure are not met, the manual start procedure may be initiated at step 314 when, in response to the operation of the retrace starter 156 by the user of the snowmobile 10, the ECU 164 initiates the engine control procedure associated with the use of the retrace starter 156 , to start the internal combustion engine 24 using the reverse starter 156. Then, in step 316, ECU 164 determines if ICE 24 has been successfully started by reversing starter 156. If not, then step 314 is repeated. It is also assumed that if it is determined at step 316 that the ICE 24 has not been successfully started, then the method may return to step 312 to re-display the message. If it is determined in step 316 that the ICE 24 has been successfully started, then the method proceeds to steps 318 and 320, these last two (2) steps being performed simultaneously. In operation 318, ECU 164 controls the ICE 24 in accordance with the control strategy or strategies intended to be used immediately after the ICE 24 has been started. In operation 320, ECU 164 controls inverter 146 to activate power supply from motor generator 144 to capacitor 145 by charging capacitor 145 with a second control strategy at a voltage that remains sufficiently constant for a wide range of crankshaft 100 speeds. This can be achieved by bypassing ECU 164 with one or more Phases A, B, and C of motor generator 144 if, in the second control strategy, motor generator 144 generates a voltage that exceeds the maximum voltage threshold. ECU 164 can linearly regulate the voltage generated by motor generator 144 by using a sequential regulation mode or a bypass mode. The maximum voltage threshold, for example, can be equal to or slightly higher than the rated voltage of circuit 200.

[00176] If the ECU 164 determines at steps 306, 308, and 310 that the capacitor voltage is equal to or greater than the electrical start voltage threshold V _MinE and that the temperature conditions and any other condition are also met, the method continues at step 324 where the ECU 164 obtains the absolute angular position of the crankshaft 100 from the DAPKV 170. This operation 324 can be continued in a continuous manner during the full electric start procedure so that subsequent operations can be optimized in accordance with the variable angular position of the crankshaft 100. It is assumed that operations 322 and 324 can be omitted or replaced by other actions. For example, the electrical start procedure can be performed regardless of the angular position of the crankshaft 100 by providing a capacitor 145, battery, or other power source with sufficient energy storage capacity to rotate crankshaft 100, ignoring its actual angular position.

[00177] The electrical start-up routine proceeds to step 326 and continues to steps 328, 330 and, if necessary, step 332. These steps begin in the sequence shown in Figure 9, but are then performed simultaneously until it is clear that the electrical start procedure was successful, or until it should be aborted.

[00178] In step 326, ECU 164 determines a torque value sufficient to drive crankshaft 100 and initiates supply of capacitor 145 to motor generator 144 via inverter 146 in accordance with a first control strategy that adapts power supply to based on a certain torque value. Power transmission drives the crankshaft 100 to rotate. In some cases ECU 164 may determine the torque value in sub-steps, in which the first sub-step includes supplying electrical power from capacitor 145 to three-phase motor generator 144 in accordance with the first torque value to activate slow cranking at the first rotational speed until until the piston moves out of its top dead center (TDC) position, based on the information provided by the DAPKV 170 and based on the contents of the control cards 166, the second sub-step includes supplying electrical power from the capacitor 145 to the three-phase motor generator 144 in accordance with a second torque value that is greater than the first torque value, to activate rotation of the crankshaft at a second rotational speed that is higher than the first rotational speed.

[00179] While step 326 is being performed, in particular while the second sub-step is being performed, if step 326 includes two sub-steps, the method proceeds to step 328, in which the ECU 164 activates the direct fuel injection injectors 132a, 132b to inject fuel into the combustion chambers 120a, 120b, and activates spark plugs 134a, 134b to ignite fuel in combustion chambers 120a, 120b, thereby accelerating crankshaft 100 rotation. The absolute angular position of crankshaft 100 can be used by ECU 164 to properly timing for fuel injection and ignition. Since the DAPKV 170 is an absolute position sensor, it can sense the position of the crankshaft 100 while stationary before starting the internal combustion engine 140. This technology provides precise timing for fuel injection and ignition at very low engine speeds, such as when the internal combustion engine 24 starts up. This technology reduces the likelihood of failure of the starting procedure due to insufficient combustion inside the combustion chambers 102A, 120B, this insufficient combustion is the result of inaccurate timing for fuel injection or ignition calculated from inaccurate crankshaft position. This technology further facilitates faster synchronization between all components of the internal combustion engine 24 that rely on the position of the crankshaft 100, when compared with the use of position sensors that require rotation of the crankshaft 100 to determine its position. It is also contemplated to use mechanical activators (not shown) operatively coupled to crankshaft 100 to control the timing for injection and ignition. In addition, it is assumed that the amount of fuel to be injected and the moment of ignition applied by ECU 164 in step 328 can be estimated using any known method, in some cases depending on one or more of the following factors: engine temperature, air temperature , atmospheric pressure and exhaust gas temperature, these values being output to ECU 164 by various sensors shown in Figure 6.

[00180] While steps 326 and 328 are performed, the method proceeds to step 330, where ECU 164 compares the rotational speed of crankshaft 100 with a minimum rotational threshold to determine if ICE 24 has been successfully started using the electrical start procedure. If the rotation speed of the crankshaft 100 is equal to or higher than the minimum rotation threshold, the ICE 24 has been successfully started, the electrical start procedure ends, and the method proceeds to 318 and 320, which are described herein above.

[00181] If, at step 330, ECU 164 determines that the ICE 24 has not yet been started, the crank speed 100 is below the minimum rotation threshold, the method continues to step 332 where ECU 164 again monitors the voltage of capacitor 145. Expect that this voltage will be somewhat reduced because the energy previously stored in the capacitor 145 was consumed during steps 326 and 328. However, if the remaining voltage of the capacitor 145 is equal to or greater than the residual voltage threshold V _MinR , the electrical start procedure returns to steps 326 and 328, which are still performed, and then to step 330. However, if ECU 164 determines in _step 332 that the capacitor voltage has dropped below the residual voltage threshold V _MinR , the method proceeds to _step 334 where ECU 164 stops supplying supply from capacitor tank 145 to motor generator 144 and terminates operations 326 and 328. Thereafter, the method proceeds from operation 334 to operation 312, which is described herein above, where ECU 164 activates display 186 to display a manual trigger indication or an auxiliary trigger indication in implementations where this option is available when then, step 312 is followed by steps 314, 316, 318 and 320 in the case of a manual start.

[00182] Figure 10 is a timing diagram showing an example of variations in motor torque resistance as a function of time, together with corresponding variations in rotational speed. Graph 400 shows the variation in torque resistance of an internal combustion engine 24 in Newton meters (Nm) versus time in seconds. Plot 400 was derived from a Simulink ™ model. As shown in graph 400, the rotation speed in the initial phase is approximately 100 revolutions per minute (rpm). The torque resistance can vary depending on the speed of rotation of the crankshaft 100. Plot 402 shows the corresponding variation in the speed of rotation of the crankshaft 100 over the same time scale. In the simulation, the two-cylinder ICE 24 is fired when the piston first reaches a position near TDC. After less than 0.1 seconds, the torque resistance becomes negative as the piston has passed its TDC. The compression present in the combustion chamber pushes the piston and accelerates the rotation of the crankshaft 100. For about 0.12 seconds, the ECU 164 controls the torque applied to the crankshaft 100 by the engine generator 144, accelerating the rotation of the crankshaft 100. The rotation speed of the crankshaft 100 reaches the highest position by about 0.17 seconds, since the piston now compresses the gases that may remain in the combustion chamber. The rotation speed decreases as the piston approaches its TDC. TDC is reached at approximately 0.32 seconds. Successful ignition occurs, after which the speed of rotation of the crankshaft 100 rapidly increases, while the torque resistance on the engine generator 144 becomes generally negative, following the shape of the gear wave, as the piston cyclically moves up and down in its cylinder.

Auxiliary start procedure

[00183] Figure 11 is a logical diagram of the method for starting the engine of Figure 2, in accordance with another implementation. The sequence shown in Figure 11 contains many operations, some of which may be performed in a variable order, some of the operations may be performed simultaneously, and some of the operations are optional. The method begins at step 600 when the ICE 24 of the snowmobile 10 is stopped. The voltage of the capacitor 145 is measured by the voltage sensor 167 in step 602. In the same step 602, the display 186 may indicate "auxiliary start" if the voltage meets or exceeds the auxiliary start voltage threshold V _MinA and if other conditions for the auxiliary start procedure described in of this document below are complied with. In operation 604, the user initiates rotation of the crankshaft 100 by pulling on the cord 158 of the reverse starter 156, this operation is recognized by the DPKV 171, which in turn sends an activation signal to the start command detector 212 to activate the ECU 164. In one embodiment, the DPKV 170 is turned on at start start procedure ECU 170, which in turn was activated DPKV 171. In another embodiment, DAPKV 170 is permanently connected to the capacitor 145, which makes it possible to determine the absolute angular position of the crankshaft 100 when the capacitor 145 holds at least a minimum charge. The detection of the initial rotation of the crankshaft 100 may depend on the detection of the DAPKV 170 that the rotation speed of the crankshaft 100 meets or exceeds the minimum rotation threshold. In operation 606, ECU 164 controls drivers 216 and 217 of transistors Q1 and Q2 to allow capacitor 145 to charge capacitor C1 until their voltage values equalize. ECU 164 and various sensors, including, in particular, DAPKV 170, are switched on from the capacitor capacitor 145 as a result of this voltage equalization. In step 608, ECU 164 performs a comparison between the capacitor voltage 145 and the auxiliary start voltage threshold V _MinA to determine whether it is possible to initiate the auxiliary start procedure for the ICE 24. If it is determined that the capacitor voltage 145 is below the auxiliary start voltage threshold V _MinA , the auxiliary start procedure is prevented. Otherwise, at step 610, it is verified that the engine temperature measured by the engine temperature sensor 172 meets or exceeds the engine temperature threshold Th0. The auxiliary start procedure is prevented if this threshold for engine temperature is not met. Otherwise, at step 612, it is verified that the ECU temperature sensor 182 is providing a ECU temperature reading 164 that meets or exceeds the ECU temperature threshold Th1. The auxiliary start procedure is prevented if this ECU temperature threshold is not met. There may be additional steps related to using measurements from other sensors included in the above description of Figure 6. These measurements may be output to ECU 164 by air temperature sensor 174, atmospheric temperature sensor 176, or timer 180. ECU 164 may be performed additional tests based on these measurements to determine the likelihood that the auxiliary launch procedure will be successful or not. For example, the auxiliary start procedure may be performed depending, in ECU 164, on a timer 180 informing ECU 164 that the time period since stopping the ICE 24 is below a predetermined time value when the user pulls on the retrace starter 156 cord 158, by operations 604. Based on the time period since the ICE 24 is stopped, it is possible to estimate whether the voltage of the capacitor 145 will fall below the threshold value V _MinA of the auxiliary start voltage, knowing the maximum charge voltage of the capacitor 145 from the previous starting sequence of the ICE 24, and based on a typical energy leakage of capacitor capacitor 145.

[00184] The display of the manual trigger indication at step 614 may be followed by any decision made by the ECU 164 to refuse to proceed to the auxiliary trigger procedure. Regardless of whether the auxiliary start procedure is prevented because the voltage of the capacitor 145 is insufficient (step 608), because the engine temperature is too low (step 610), because the ECU temperature is too low (step 612), the method proceeds to operation 614. At operation 614, display 186 may display "Manual Start." After step 614, the user may continue to pull on the recoil starter cord 158 156 at step 616. Step 616 may continue until it is determined at step 618 that the ICE 24 has been properly started. The control of the internal combustion engine 24 and the supply of electrical power from the engine generator 144 to the capacitor 145 occurs at 620 and 622, which are the same or equivalent to operations 318 and 320 of Figure 9, including, in implementation, the control of the internal combustion engine 24 using the above control strategies ...

[00185] If at steps 608, 610 and 612 ECU 164 determines that the capacitor voltage is equal to or higher than the threshold value V _MinA of the electrical start voltage and that the temperature conditions and any additional condition are also met, the method continues at step 624, where DAPKV 170 determines the current absolute angular position of the crankshaft 100.

[00186] The auxiliary start routine proceeds to operation 626 and continues to operations 628, 630 and, if necessary, operation 632. These operations begin in the sequence shown in Figure 11, but are then performed simultaneously until it is clear that the auxiliary start procedure was successful, or until it should be aborted.

[00187] In step 626, ECU 164 initiates a supply of power from capacitor 145 to motor generator 144 through inverter 146. This power transfer accelerates crankshaft 100 rotation and reduces the amount of effort the user must exert to pull the retraction starter cord 158 156 ... In some cases, ECU 164 may determine the torque value in the same manner as described in the above description of operation 326 (Figure 9).

[00188] While step 626 is performed, the method proceeds to step 628 where ECU 164 activates direct fuel injectors 132a, 132b to inject fuel into combustion chambers 120a, 120b and activates ignition plugs 134a, 134b to ignite fuel in chambers 120a, 120b combustion, thereby accelerating the rotation of the crankshaft 100. The angular position of the crankshaft 100 is used by the ECU 164 to properly time the injection and ignition of the fuel. It is assumed that the amount of fuel to be injected and the moment of ignition applied by ECU 164 in step 628 may depend on one or more of the following factors: engine temperature, air temperature, atmospheric pressure and exhaust gas temperature, and these values are output to ECU 164 different sensors shown in Figure 6.

[00189] While 626 and 628 are running, the method proceeds to step 630 where ECU 164 compares the crankshaft 100 RPM to the minimum RPM threshold to determine if ICE 24 has been successfully started using the auxiliary start procedure. If the rotation speed of the crankshaft 100 is equal to or higher than the minimum rotation threshold, the ICE 24 has been successfully started, the auxiliary start procedure ends, and the method proceeds to 620 and 622, which are described herein above.

[00190] If, at step 630, ECU 164 determines that ICE 24 has not yet been started, and the crank speed 100 is below the minimum rotation threshold, the method continues at step 632 where ECU 164 again monitors the voltage of capacitor 145. Expect that this voltage will be somewhat reduced because the energy previously stored in capacitor 145 was consumed during times 626 and 628. However, if the remaining voltage of capacitor 145 is equal to or greater than the residual voltage threshold, the auxiliary start procedure returns to steps 626 and 628, which are still performed, and then to step 630. In one embodiment, the residual voltage threshold applicable to the auxiliary start procedure may be the same V _MinR value as for the electrical start procedure. Alternatively, a different residual voltage threshold may be used, provided that the amount of power supplied to the motor generator 144 by capacitor 145 complements the force of the user pulling the retraction starter cord 158 156. However, if ECU 164 determines in _step 632 that the capacitor voltage has dropped below the residual voltage threshold V _MinR , the method proceeds to _step 634 where ECU 164 stops supplying power from capacitor 145 to motor generator 144 and terminates steps 626 and 628. The method then proceeds from step 634 to step 614 as described herein above, where ECU 164 activates display 186 to display a manual start indication, with step 614 followed by steps 616, 618, 620, and 622.

[00191] In an implementation, the snowmobile 10 may be configured to support any one of manual, electrical, and assisted starting procedures. In such an implementation, operation 312 (FIG. 9) may indicate a manual start or an auxiliary start depending on the voltage of the capacitor 145. If the voltage of the capacitor is below the threshold value V _MinE of the electric start voltage while meeting or exceeding the threshold value V _MinA of the auxiliary start voltage operation 312 of Figure 9 may provide an auxiliary start indication and may be followed by operation 604 of Figure 11 if the user pulls on the recoil starter cord 158 156. Also in this implementation, after starting the ICE 24 using the auxiliary start procedure, the ICE 24 can be stopped, and the display 186 can give an indication of the available start procedure depending on the current conditions sent to the ECU 164 by various sensors.

Implementation of control strategies

[00192] As explained herein above, ECU 164 controls inverter 146 via strategy switch 184. To this end, ECU 164 generates control pulses that are applied to the strategy switch 184. These control pulses are generated separately in two (2) control strategies. In at least one implementation, the effect of these control pulses depends on the internal structure of inverter 144. Figure 12 is a circuit diagram showing connections of inverter 146, capacitor 145, and motor generator 144 of Figure 6. As shown in Figure 12, inverter 146 has three phases, each phase is electrically connected to a corresponding phase of the three-phase motor generator 144. In more detail, the inverter 146 is formed by three (3) switching legs, each switching leg contains a pair of MOS transistors T1, T2, T3, T4, T5 and T6, coinciding with the corresponding diodes D2, Dl, D3, D2, D6 and D5 of the reverse circuit. For example, the first leg, forming the first phase, contains an upper transistor T1, which coincides with the reverse diode D2, and a lower transistor T2, which coincides with the reverse diode D1. The second leg, forming the second phase, contains transistors T3 and T4, which coincide with diodes D4 and D3, respectively, while the third leg, forming the third phase, contains transistors T5 and T6, which coincide with diodes D6 and D5, respectively. Also, bipolar transistors such as IGBTs or any other power electronic switches are contemplated as a replacement for MOSFETs. Each transistor T1-T6 has a corresponding gate G1-G6 through which a signal or control pulse can be applied under the control of ECU 164 via the strategy switch 184 directly or via a gate driver (not shown) for on (closed circuit) or off (open circuit) corresponding transistors T1-T6. The reverse diodes D1-D6 are used to reduce the transient overvoltage that occurs after turning on and off transistors T1-T6.

[00193] For example, when the engine generator 144 is in the operating mode of the engine used as a starter for the internal combustion engine 24, a first control pulse is applied to the gate G1 to establish a closed circuit for the transistor T1. The current flows from the plus plate of the capacitor capacitor 145 through the transistor T1 and reaches the phase of the motor generator 144, defined between the input A and the neutral connection between the phases of the motor generator 144, hereinafter referred to as "Phase A". Thereafter, the first drive pulse is removed from the gate of G1, so that the transistor T1 becomes an open circuit. At the same time, a second control pulse is applied to the gate of G2, activating the turn on of the transistor T2. Current now flows in the opposite direction in Phase A of motor generator 144, returning to the negative capacitor plate 145 through transistor T2. As a result of this on and off sequence of transistors T1 and T2, alternating current flows in Phase A of motor generator 144.

[00194] The current flowing in Phase A of motor generator 144 must exit through one or both of the other phases of motor generator 144. "Phase B" is defined between input B and a neutral connection. "Phase C" is defined between the C input and the neutral connection. Current flows from Phase A through Phase B or Phase C, or both Phases B and C, depending on whether one or both T4 or T6 is turned on by control pulses applied to their respective gates G4 or G6 when T1 is also turned on. ... The current exiting the motor generator 144 through one or both of Phases B and / or C is returned to the negative capacitor plate 145 through one or both of the transistors T4 and / or T6. The reverse circuit diodes D1-D6 help maintain the phase induction current during the reverse circuit periods.

[00195] To operate motor generator 144 as a conventional three-phase motor, current can flow simultaneously in all three (3) Phases A, B, and C, and the timing control of the various transistors T1-T6 is separated by 120 degrees. However, other operating modes of motor generator 144 are contemplated in which the current does not flow simultaneously in all three (3) Phases A, B and C.

[00196] Examples of parameters that can be considered by programming ECU 164 to control power supply in both strategies include, without limitation, current and voltage of each phase, current and voltage in each of Phases A, B and C of motor generator 144 , the angular position and speed of rotation of the crankshaft 100. ECU 164 uses these values to determine the electromagnetic torque of the engine generator 144, this torque is positive when the engine generator 144 is used during the electric start procedure or the auxiliary start procedure, and negative value when used in operating mode of the generator.

[00197] The first control strategy uses a technique called vector control. Applicable examples of vector control technology include field-oriented control (FOC), direct torque control (FPC), direct self-control (DCM), space vector modulation (STM), and the like. Use of any of the applicable vector control technologies is provided for and is within the scope of this disclosure. The first control strategy is used primarily to control the supply of electrical power from the capacitor 145 to the engine generator 144 to activate or assist rotation of the crankshaft 100 during an electric start procedure or during an auxiliary start procedure for the internal combustion engine 24. In one implementation, ECU 164 determines a torque request, sufficient to drive the crankshaft 100 in rotation. In another implementation, ECU 164 determines a speed request applied to crankshaft 100 sufficient to activate ignition and start ICE 24. This speed request or torque request determination may be performed by ECU 164 using a predetermined value or pattern of speed or torque request on based on the content of the 166 control cards. ECU 164 can increase the torque demand if the application of torque does not cause the crankshaft 100 to rotate. ECU 164 can increase the speed demand if the rotation of the crankshaft 100 is insufficient to allow ignition and start of the ICE 24. Alternatively, ECU 164 can calculate a speed or torque request based on a combination of parameters, including, in a non-limiting example, a mathematical representation of the internal components of the ICE 24, and based on the absolute angular position of the crankshaft 100. ECU 164 controls the supply of electrical power from capacitor 145 to engine generator 144 based on a specific speed request or torque request by generating control pulses applied to the transistors selected from T1-T6. Using vector control, ECU 164 calculates the number, timing, and width of various control pulses so that the amount of electrical power flowing from capacitor 145 through inverter 146 and to motor generator 144 satisfies a specific speed or torque demand. This method of controlling transistors T1-T6 by applying clock pulses to their gates G1-G6, each of the pulses having a calculated width, is known as pulse width modulation (PWM).

[00198] Figure 13 is a block diagram of a typical implementation of a vector control drive. The vector control drive 500 of Figure 13 may be implemented at least in part in ECU 164. The input data to the vector control drive contains a setpoint 504 for a desired speed (speed request) that is determined to be sufficient to start ICE 24. This setpoint point 504 applies to low speed control loop 506. Other inputs to vector control drive 500 include current measurements 508 _a , 508 _b and 508 _c for the three phases of motor generator 144 and voltage measurement 510 from inverter 146 and / or motor generator 144. These current and voltage measurements apply to analog-to-digital converter (ADC) 512. Crankshaft angular position measurements 514 (encoder signals u _A , u _S ) obtained from DAPKV 170 are applied to a quadrature timer 516. Since engine generator 144 is mounted coaxially with respect to crankshaft 100, the encoder signals u _A , u _S 514 also represent the actual angular position of the rotor 150 of the motor of the generator 144. The vector control drive 500 uses this information to calculate the torque demand as explained in the following paragraphs. Quadrature timer 516 calculates the current position of the crankshaft 100. The ADC 512 calculates the digitized voltage value 518 and the digitized current values 520 _a , 520 _b and 520 _c for the three phases of the engine generator 144. These digitized values and the current position 522 of the crankshaft 100, calculated by the quadrature timer 516 are provided to the fast current control loop 524. The current position 522 of the crankshaft 100 is converted to the current (measured) speed 526 by the speed computer 528 in the low speed control loop 506. The difference 528 between the measured speed 526 and the desired speed setpoint 504 is applied to the first proportional-integral (PI) controller 530, which in turn outputs a current image 532 in the torque request, which is applied as setpoint (Isq_req) to the fast response current control loop 524.

[00199] As explained herein above, in some embodiments it may be desirable to control motor generator 144 to provide electrical power to capacitor 145 in accordance with a first control strategy, at least at low crankshaft speeds 100 To this end, an optional field weakening module 534 having an internal map attenuates the values at its output based on the measured speed 526 of the crankshaft 100 to provide an image 536 of the magnetic field current of the engine generator 144 as an additional set point (Isd_req) applied to fast current control loop 524.

[00200] In the fast current control loop 524, Clarke transform 538 converts measurements 520 _a , 520 _b, and 520 _from three-phase current to two-phase model 540. Park transform 542 fed the sine and cosine values 523 of the current position 522 of crankshaft 100, calculated sinuso -cosine converter 525 further transforms this model 540 to provide a stationary image 544 of the current torque of the motor generator 144 (Isq) and a stationary image 546 of the current magnetic field of the motor generator (Isd). Pins 544 and 546 of this model, respectively, are compared to the Isq_req set point 532 and Isq_req set point 536 (if used), and the differences between them, respectively, are fed to the second and third PI controllers 548, 550. Inverse Park transform 552 is applied to the stationary voltage requests Uq 554 and Ud 556 issued by the second and third PI-controllers 548, 550, the Park inverse transformation 552 uses the values 523 of the sine and cosine of the current position 522 of the crankshaft 100 to produce the output data 558, 560 of the Park 552 inverse transformation, which applied to transform 562 space vector modulation to pulse width modulation (PWM). In turn, the PW-PWM conversion 562 provides three-phase control 564 to the PWM module 566, which generates pulses 502, which ECU 164 outputs for application to the gates G1-G6 of the inverter 146.

[00201] ECU 164 may control the supply of electrical power from capacitor 145 to engine generator 144 based on a predetermined torque value, or a request for torque sufficient to drive crankshaft 100 to rotate to start ICE 24. However, considering that the amount of torque required to rotate the crankshaft 100 prior to ignition in the cylinder (or cylinders) varies based on the angular position of the crankshaft 100 relative to the top dead center (TDC) position of each piston, and variable torque is also assumed. The absolute angular position of the crankshaft 100 is provided by the DAPKV 170. In the embodiment included in the above description of operation 326 (Figure 9), the ECU 164 calculates or otherwise determines the torque demand based on the angular position of the crankshaft 100 issued by the DAPKV 170, the torque demand value the torques are updated at different points of rotation of the crankshaft 100. As a result, the torque demand can be optimized so that there is enough to rotate the crankshaft 100 when it reaches different angular positions, while using so little energy stored in the capacitor 145, as much as possible. In a particular embodiment, ECU 164 controls the amount of torque applied to engine generator 144 so that it turns at a very low speed until a predetermined piston 116A, 116B passes its TDC for the first time. During this brief period of time, gas slowly exits the combustion chamber 120A, 120B in which this predetermined piston 116A, 116B is located. In this operation, capacitor 145 delivers very little power. Once piston 116A, 116B exited its TDC, crankshaft 100 received at least some kick. ECU 164 then increases the torque request to engine generator 144 so that crankshaft 100 rotates at a speed sufficient to allow fuel to be injected into combustion chamber 120A, 120B as piston 116A, 116B moves towards its TDC position, ignition occurs in chamber 120A, 120B combustion as soon as the piston has moved out of its TDC. This increase in torque demand may be linear until a predetermined set point of torque is reached, so that the rotational speed of the crankshaft 100 increases gradually.

[00202] After starting the ICE 24, regardless of whether the ICE 24 was started by a manual start procedure, an auxiliary start procedure, or an electric start procedure, the crankshaft 100 drives the engine generator 144 at a variable speed, which is significantly exceeds the rotational speed used during any of the startup procedures. Immediately after starting the internal combustion engine 24, the operation of the engine generator 144 switches to operation as a generator. In an implementation, the ECU 164 may determine the rotational speed of the crankshaft 100 based on sequential readings provided by the DPKV 171 or the DAPKV 170, and activate the engine generator 144 to start supplying electrical power to the capacitor 145 when the crankshaft rotational speed meets the minimum rotation threshold or exceeds it. At or shortly thereafter, ECU 164 starts controlling the strategy switch 184 and the inverter 146 with the second control strategy. In some cases, the first control strategy can be used in a mode of operation as a generator until the voltage measurement provided by the voltage sensor 167 meets or exceeds the generated voltage threshold. The threshold value of the generated voltage can be set, for example, slightly below the rated voltage of the capacitor capacitor 145.

[00203] The second control strategy uses shunting technology. The output of the engine generator 144, which is a generator at this moment, is used to charge the capacitor 145, to supply electrical power to the direct fuel injection injectors 132a, 132b, to ignite the ignition plugs 134a, 134b and, in general, to supply electrical power to the electric snowmobile accessories 10.To this end, ECU 164 changes the position of the strategy switch 184 so that power now flows from motor generator 144 to capacitor 145, still through inverter 146. ECU 164 monitors the voltage of capacitor 145 through measurements obtained from the voltage sensor 167. Based on these voltage measurements, ECU 164 generates control pulses that are applied by the strategy switch 184 to the gates G1-G6 of transistors T1-T6 in inverter 146. PWM is still applied by ECU 164 to gates G1-G6, but now in accordance with the second strategy management.

[00204] If the output voltage of the motor generator 144 is above its nominal value or above its nominal value plus a predetermined error factor, ECU 164 controls inverter 146 to reduce the voltage at which power is supplied from motor generator 144 to capacitor 145. C for this purpose, in a single operating mode, referred to as a leakage control mode, the ECU 164 can generate control pulses applied to various gates G2, G4 and G6 to effectively bypass or "bypass" one or more phases of the motor generator 144, while time without applying a control pulse to gates G1, G3 and G5 in order to leave transistors T1, T3 and T5 non-conductive (open circuit). For example, applying pulses to gates G2 and G6 activates transistors T2 and T6, and they become conductive. As a result, a closed loop is formed between Phases A and C of motor generator 144 together with transistors T2 and T6. Under this condition, no electrical power is supplied to the capacitor 145 from the two (2) phases of the motor generator 144. The duration (width) and timing of the pulses applied to the gates G2 and G6 affect the length of time that Phases A and C are withdrawn, affecting in turn the charging voltage applied to the capacitor 145. PWM can be applied to any pair of lower transistors T2, T4, and T6 so that they can be closed at the desired time to bypass the motor-generator 144 phase pair.Over time ECU 164 can actually modify the determination of which pair of transistors is part of the bypass in order to prevent them overheating due to loss of conduction in the inverter 146. For this purpose, voltage regulation in the bypass mode involves the sequential activation of transistors T2, T4 and T6. As a result, the supply of electrical power from the engine generator 144 to the capacitor 145 can be performed at a desired voltage within a wide range of the rotational speed of the crankshaft 100. A sequential voltage control mode is also contemplated, in which the reverse diodes D1, D3 and D5 may optionally be replaced by additional transistors (not shown) installed back in parallel with transistors T1, T3 and T5, these additional transistors are turned on and off depending on the need to ensure that the capacitor capacitor 145 can be recharged with a current from the motor generator 144 without exceeding the value of the rated voltage.

[00205] In a particular implementation, the voltage regulation in the bypass mode may use measurements provided by the DPKV 171 or DAPKV 170. In this implementation, the DPKV 171 or DAPKV 170 provides the ECU 164 with the ability to determine the mechanical position of the crankshaft 100. The ECU 164 calculates the equivalent electrical angle by multiplying the mechanical position of the crankshaft 100 for a known number of pole pairs of the engine-generator 144. If the output voltage of the engine-generator 144 is higher than a predetermined value, starting from an increase in voltage in any one of phases A, B or C, all three (3) phases are sequentially diverted synchronously with the operation of the engine generator 144. This shunting sequence may be repeated when the output voltage of the engine generator 144 rises above a predetermined value again.

[00206] If the voltage of capacitor 145 is equal to or below its nominal value, ECU 164 controls inverter 146 to supply available electrical power from motor generator 144 to capacitor 145 without shunting any of Phases A, B, or C. Under this condition, which may, for example, occur in the case of a short duration after starting the ICE 24, the control of the supply of electrical power can be considered as a neutral control mode, different from the first and second control strategies. In neutral control mode, the inverter 146 acts as a three-phase full-wave diode bridge rectifier without providing any voltage or current regulation.

[00207] Figure 14 is a block diagram of an electrical system in accordance with an implementation of the present technology. Circuit 700 contains variants of elements included in the above description of various drawings, these elements are grouped into subsystems. Motor generator 144 is one such subsystem. Another subsystem is presented in the form of a control module 702, which, in implementation, contains one physical module containing a processor 703 programmed to perform the functions of the ECU 164, an inverter 146, an ECU temperature sensor 182, and additionally contains a DC-DC converter 704. As shown, ECU 164 includes connections for electrical start switch 168 for measurements from various sensors 167, 170, 171, 172, 174, 176 and 182, and connections to gates G1-G6 of inverter 146. In the illustrated example, voltage sensor 167 is implemented in the form of a _DC voltage sensor 167 that measures the voltage of the capacitor 145, and in the form of an _AC voltage sensor 167 that measures the voltage on one phase of the motor generator 144, these two components of the voltage sensor 167 are integrated into the ECU 164. It is also assumed the use of external voltage sensors functionally connected to the ECU 164. The third subsystem 706 contains a capacitor capacitor 145, as well as a charging circuit 705 and a discharge circuit 707, which respectively use drivers 216 and 217 and transistors Q1 and Q2 of Figure 8 to control the charging and discharging of the capacitor containers 145.

[00208] The circuit 700 operates at the nominal system voltage, which is typically the voltage of capacitor 145 when fully charged. The fourth subsystem 708 contains the components of the snowmobile 10 that function when the system is energized. These components may include direct fuel injectors 132a, 132b, an electric oil pump 710, ignition coils 712 for spark plugs 134a, 134b, and a fuel pump 714. A fifth subsystem 716 contains accessories of the snowmobile 10 that operate on auxiliary voltage. These accessories may include a multiport fuel injector (MPTF) 718, headlight 720, instrument panel 722 containing display 186, heated steering knobs 724 mounted on steering wheel 36, and exhaust valve 726. DC / DC converter 704 converts system voltage to auxiliary voltage and thus provides electrical power to the accessories.

[00209] In an implementation, circuit 700 typically operates at a system voltage of 55 volts, and some snowmobile accessories typically operate at an auxiliary voltage of 12 volts. Various sensors 167, 170, 171, 172, 174, 176, and 182 can operate at system voltage or auxiliary voltage, or any other voltage, if an optional voltage converter (not shown) is included in circuit 700. In this implementation, the DC / DC converter 704 is a 55V-12V converter. These system voltages and auxiliary voltages are nominal for a given implementation and may vary according to the current operating conditions of the snowmobile 10.

[00210] Figure 15 is a timing diagram showing an example of a sequence for changing a control strategy for supplying electrical power between capacitor 145 and motor generator 144, together with corresponding variations in engine speed. Plot 410 shows the variation of the control strategies for supplying electrical power applied by ECU 164 versus time in seconds. In this graph 410, "Strategy 1" indicates the application of the first control strategy, in particular using vector control, "Strategy 2" indicates the application of the second control strategy, which uses shunting the phases of the motor generator 144 to control the voltage used to charge the capacitor 145, and "Neutral" indicates the use of neutral control mode. In neutral control mode, the voltage generated by motor generator 144 can simply be converted to direct current and used to charge capacitor 145, provided that the peak back electromotive force voltage of motor generator 144 is higher than the rated voltage of circuit 200, this condition is usually met. when the internal combustion engine 24 reaches a sufficient rotational speed. Plot 412 shows the corresponding variation in the speed of rotation of the crankshaft 100 over the same time scale. In the first half of a second of operation following a user command for the electric start procedure of the ICE 24, no electrical power is supplied between the capacitor capacitor 145 and the engine generator 144. This period is used to balance the voltages of the capacitor 145 and the capacitor C1. The actual duration of this period can vary significantly depending on the value of the capacitor C1. The period in the range from 0.5 to about 1.1 seconds approximately corresponds to the period between 0 and 0.4 seconds covered in graphs 400 and 402. ECU 164 uses the first control strategy (Strategy 1) to control the supply of electrical power from the capacitor 145 to the engine generator 144 until the internal combustion engine 24 is actually started. Then, between 1.1 and 1.3 seconds as the internal combustion engine 24 accelerates, electrical power is supplied from the motor generator 144 to the capacitor 145 in the neutral control mode. When the crankshaft 100 reaches a sufficient rotational speed, for about 1.3 seconds, the engine generator 144 begins to generate power at a voltage that tends to exceed the rated voltage of the capacitor 145. This occurs when ECU 164 begins to use the second control strategy (Strategy 2) to control the supply of electrical power from the engine generator 144 to the capacitor 145 and various electrical consumers (not shown) of the vehicle. It is also contemplated in which the neutral control mode is not implemented, in which the ECU 164 starts using the second control strategy immediately after the ICE 24 has been successfully started.

[00211] Figure 16 is another timing diagram showing an example of the effect of control strategies on the exchange of current between the capacitor and the EPC and on the system voltage. Plot 420 shows the voltage of one of Phases A, B, or C of motor generator 144 versus time in seconds and versus control strategies. In a first control strategy, ECU 164 controls the application of control pulses to motor generator 144 in a pulse width modulation (PWM) mode at a very fast frequency, which is typically expressed in kilohertz. Thereafter, as the ICE 24 starts to start in the neutral control mode, the engine generator 144 independently begins to generate a voltage that increases until the mode is changed to the second control strategy, the voltage cycling occurs with a frequency that follows the rotation of the crank shaft 100. It can be observed that due to the configuration of the inverter 146, the voltage on each phase of the motor generator changes between zero (0) volts and the nominal voltage of the system without cycling through negative values. Plot 422 shows the variation in current flowing between capacitor 145 and motor generator 144 as ECU 164 of the first control strategy changes to neutral control mode and to the second control strategy. Initially, in the first control strategy, three-phase current flows from capacitor 145 to motor generator 144 through inverter 146. For most of the neutral control strategy, all inverter transistors T1-T6 are open and no current flows between capacitor 145 and motor generator 144. After starting the internal combustion engine 24, each phase of the engine generator 144 generates a significant current. ECU 164 shorts the phases of motor generator 144 to prevent overvoltage at its output, as depicted by the strong current variations on the right side of graph 422. Graph 424 shows the current voltage measured across capacitor 145 as ECU 164 of the first control strategy changes to neutral. management and the second management strategy. The voltage of the capacitor capacitor 145 initially decreases when electric power is supplied to the engine-generator 145. After starting the internal combustion engine 24, the ECU 164 switches the system to a neutral control mode. Discharging the reverse circuit diodes D1-D6 causes a small increase in the voltage of the capacitor 145. Opening the transistor Q2 at the start of operation in the second control strategy temporarily isolates the capacitor 145 from the motor generator so that the electrical power generated by the motor generator is generally available to others. system needs such as injection, ignition, control and the like. Closing the transistor Q1 allows capacitor 145 to be charged at a voltage that fluctuates around the nominal system voltage in accordance with the shunting of the motor generator 144.

[00212] The time values, rotational speed values and torque values depicted in various graphs 400, 402, 410, 412, 420, 422 and 424 are presented for purposes of illustration and do not limit the present disclosure. Actual values may largely depend on the design of the internal combustion engine 24, the engine-generator 144, the capacitor capacitor 145, and the operating strategy of the ECU 164.

Concrete application of the first control strategy

[00213] Here will be described the implementation of the first control strategy applicable to both the electric start procedure and the auxiliary start procedure. As explained herein above, the present snowmobile 10 (or other vehicle constructed in accordance with the teachings of the present disclosure) includes an internal combustion engine 24 equipped with an engine generator 144 operatively coupled to a crankshaft 100, a capacitor capacitor 145, an ECU 164, one injector 132A, 132B direct fuel injection in each cylinder 106A, 106B and DAPKV 170 or an equivalent sensor that provides ECU 164 with the ability to continuously obtain information about the absolute angular position of the crankshaft 100 while DAPKV 170 and ECU 164 are in the on state.

[00214] In an implementation where the internal combustion engine 24 is not equipped with a decompression system, the capacitor 145 and the engine generator 144 may be unable to generate sufficient torque to quickly remove gases remaining in the combustion chambers 120A, 120B after the internal combustion engine 24 is stopped. implementations, a low level of torque is first applied to crankshaft 100 so that pistons 116A, 116B slowly expel residual gases from combustion chambers 120A, 120B. After sufficient gas has been removed, a higher level of torque is applied to crankshaft 100 to drive one of pistons 116A, 116B to TDC and beyond to start ICE 24. In another implementation where ICE 24 is equipped with a decompression system (not shown), or in yet another implementation, where capacitor 145 and motor / generator 144 are capable of generating sufficient torque, higher torque can be applied to the crankshaft throughout the procedure.

[00215] In an implementation without a decompression system, when the internal combustion engine 24 is stopped, the pistons 116A, 116B rapidly decelerate and tend to effectively stop moving at a natural point where the pressure in the combustion chambers 120A, 120B is low enough. In a two-cylinder engine, one of the pistons 116A or 116B typically stops at approximately 100 to 80 degrees before TDC due to the configuration of the main and secondary outlets 136A, 136B, 138A, 138B. When the internal combustion engine 24 is restarted, this piston 116A or 116B first moves upward towards the TDC position. In the implementation shown, for example, in Figures 4A and 4B, the upward movement of the piston (piston 116B in Figures 4A and 4B) tends to push the gases remaining in the combustion chamber 120B to exit through the main outlet 136B and through the auxiliary outlet 138B. , a portion of the remaining gas also bypasses at least one ring 117B of piston 116B until piston 116B is approximately 50 to 0 degrees before TDC. Since the outlets 136B, 138B are initially open to about 60 degrees before TDC, this movement of piston 116B requires very little energy. At the same time, the opposing piston 116A moves away from its TDC position and does not compress, so this movement of the opposing piston 116A also takes place with very little energy.

[00216] Once the outlets 136B, 138B are closed, the piston 116B begins to compress the gases remaining in the combustion chamber 120A, with a small portion of the remaining gases being displaced around at least one ring 117A of the piston 116B. More force is required to keep the crankshaft 100 rotating, and more torque is applied from when piston 117 B is approximately 50 to 0 degrees before TDC.

[00217] Immediately after the piston 116B passes the TDC position, it is in the proper position for ignition. Due to the absolute angular position of the crankshaft 100, provided by the DAPKV 170, the moment when the piston 116B is in the TDC position is known with sufficient accuracy so that the ECU 164 can control the injection of a fuel amount, which can be calculated in part based on the readings of one or several of the following sensors 167, 170, 171, 172, 174, 176 and 182, in the combustion chamber 120B by direct injection injector 132B when the piston 116B is in the range of approximately 3 degrees before TDC to 7 degrees after TDC, and then control the ignition fuel spark plug 134B before piston 116B passes TDC again, for example 0 to 12 degrees after TDC.

[00218] Figure 17 is another timing diagram showing an example of the change in torque acting on the EPC in the first control strategy. Graph 430 shows the variation in torque supplied to motor generator 144 versus time in seconds. Graph 430 is not to scale. The operation of the ICE 24 during the period shown in the graph 430 belongs to the first control strategy, since the supply of electrical power is from the capacitor 145 to the motor generator 144.

[00219] The level of torque applied to the motor generator 144 can be controlled by controlling the current supplied through the inverter 146 to the motor generator 144. To this end, the vector technology described above, including any of its variants, can use absolute angular the position of the crankshaft 100 to obtain the absolute angular position of the rotor 150 of the engine generator 144, which in turn is used as a basis for regulating the current and therefore the level of torque applied by the engine generator 144 to the crankshaft 100. Referring again to Figure 13, the absolute angular position of the crankshaft 100 is encrypted as the signals u _A , u _S 514 are applied to the quadrature timer 516 of the vector control actuator 500.

[00220] In the implementation of the procedure for the electric start of the internal combustion engine 24 is stopped at the initial time t ₀ (0 sec.), And operations 300, 302, 304, 322, 306, 308 and 310 shown in Figure 9 (some of which are optional) just finished. In the implementation of the auxiliary start procedure, rotation of the crankshaft 100 is initiated by the user. Operations 600, 602, 604, 606, 608, 610, 612 depicted in Figure 11 (some of which are optional) have just completed at the start time t ₀ . In both cases, DAPKV 170 turns on and is ready to determine the absolute angular position of the crankshaft 100 (or, alternatively, the absolute position sensor detects the angular position of the ICE component 24 rotating synchronously with the crankshaft 100, for example, the sensor 177 transmits the angular position of the water pump 173 ) in both step 324 for the electrical start procedure and step 624 for the auxiliary start procedure. Starting from this point, the sequence shown in graph 430 applies to both procedures. As explained herein above, in a two-cylinder engine, one of the pistons 116A, 116B will typically stop at a predetermined position, about 100 to 80 degrees before TDC, if the ICE 24 is stopped at the initial time to, and this condition is.

[00221] In response to the user's command to start the internal combustion engine 24, either in the form of activation of the electric start switch 168 or in the form of pull on the cord 158 of the reverse starter 156, the ECU 164 controls the start of the electric power supply to the engine generator 144 to rotate the crankshaft 100 Vector control actuator 500 controls the level of torque applied to rotor 150 of motor generator 144. Torque is initially applied at a moderate level ε from an initial time t ₀ when piston 116B is approximately between 100 and 80 degrees before TDC. The torque increases in the direction of level α until the time t ₁ , when the piston is approximately 50 to 0 degrees before TDC. At this time, piston 116b effectively blocks outlets 136B and 138B, and any gas remaining in combustion chamber 120B will be either compressed or expelled at a reduced speed around at least one ring 117B. From this point in time t _{1, the} vector control drive 500 controls the torque supply to an increased β level. Shortly thereafter, at time 12, the piston ranges from about 3 degrees before TDC to 7 degrees after TDC. ECU 164 activates direct fuel injection injector 132B to inject a calculated amount of fuel into combustion chamber 120B. Then, at time t ₃ , when piston 116B is between about 0 and 12 degrees after TDC, ECU 164 activates spark plug 134B to ignite fuel in combustion chamber 120B. This ignition in many cases effectively starts the ICE 24 at time t ₄ .

[00222] Of course, starting the internal combustion engine 24 may require continuous supply of torque to the crankshaft 100 by the engine generator 144, as well as the injection and ignition of fuel in the combustion chambers 120A, 120B, in several cycles of operations 326, 328, 330 and 332 of Figure 9 or in several cycles of operations 626, 628, 630 and 632 of Figure 11. ICE 24 is considered to be started at time t ₅ when the crankshaft reaches a predetermined rotation threshold, for example 600 rpm. ICE 24 is now in neutral control mode.

[00223] The torque α from the start time t ₀ to the time t ₁ may be constant. In the example of Figure 17, electrical power is first supplied from capacitor 145 to motor generator 144 at a gradually increasing rate, providing torque increasing from a low level 6 (which may be zero or slightly greater than zero) until at time time t ₁ , a torque level α in the range of one to ten Newton meters (1-10 Nm) will not be reached. When piston 116B is approximately 50 to 0 degrees ahead of TDC at time t ₁ , torque is applied at an increased β level sufficient to move piston 116B past TDC, for example in the range of 10 to 15 Nm. In an implementation, the level of electrical supply providing this amount of torque β corresponds to the maximum power supply capacity of the capacitor 145. In the same or another implementation, the level of electrical supply providing this amount of torque β corresponds to the maximum amount of power and torque that can be sustained motor generator 144. The torque values described herein and the times shown in Figure 17 are exemplary and do not limit the present disclosure. In an implementation where the internal combustion engine 24 is equipped with a decompression system, the torque may be applied at an increased β level from the initial time t ₀ until the time when the internal combustion engine 24 is properly started.

[00224] Figure 18 is a sequence diagram showing method steps for starting an internal combustion engine. The sequence shown in Figure 18 contains many operations, some of which may be performed in a variable order, some operations may be performed concurrently, and some operations are optional. The sequence of Figure 18 is implemented in an internal combustion engine 24 in which the engine generator 144 is operatively coupled to the crankshaft 100. The sequence in one implementation corresponds to steps 324, 326, 328 and 330 of FIG. 9, and in the same or another implementation to steps 624, 626 , 628 and 630 of Figure 11. For clarity and without loss of generality, the sequence is described with piston 116B at a predetermined position between approximately 100 and 80 degrees before TDC while the user has initiated one of the procedures, the electrical procedure. or auxiliary launch. The crankshaft 100 is not rotating at this time (electric start procedure) or is just starting to rotate (auxiliary start procedure). Initial injection and ignition will occur in combustion chamber 120B corresponding to piston 116B. At this time, the opposing piston 116A is between approximately 80 and 100 degrees after TDC and will move away from TDC without compressing the gases in combustion chamber 120A.

[00225] The sequence begins at step 800 when an absolute position sensor, such as DAPKV 170, is turned on to begin determining the absolute angular position of the crankshaft 100 when the ICE 24 is stopped or starts to rotate. DAPKV 170 remains on when the crankshaft 100 rotates. The absolute angular position of the crankshaft 100 is determined in step 802, with the absolute angular position of the crankshaft 100 being related to the TDC position of the piston 116B in the combustion chamber 120B of the ICE 24. As explained herein above, the DAPKV 170 can be replaced by any absolute angular position sensor ( not shown), which determines the absolute angular position of the ICE component 24 rotating synchronously with the crankshaft 100. In any case, the ECU 164 calculates the absolute angular position of the crankshaft 100 based on the reading transmitted by the DAPKV 170 or based on the detected absolute angular position of the ICE component rotating synchronously with crankshaft 100. In step 804, when the ICE 24 is not equipped with a decompression system, electrical power is supplied from capacitor 145 to engine generator 144 at a first level to rotate crankshaft 100. In some cases, step 804 may include a sub-step 806. in which n The supply of electrical power to the motor generator 144 gradually increases from the initial level ε to the first level, as shown in Figure 17, between times t ₀ and t ₁ . The first level, and in particular the initial level 6, and the power supply transition between times t ₀ and t ₁ can be determined taking into account the initial angular position of the crankshaft 100. The first level of electrical power supply is designed so that the engine generator 145 generates sufficient torque to rotate the crankshaft 100 until the piston 116B reaches a predetermined position before the TDC position, for example, between 50 and 0 degrees before TDC. At step 808, electrical power is then supplied from capacitor 145 to motor generator 144 at a second level more than at a first level when piston 116B reaches a predetermined position before TDC. The second level of electrical power is calculated so that the motor generator 144 generates sufficient torque to move the piston past the TDC position. In more detail, the vector control actuator 500 determines the angular position of the rotor 150 of the engine generator 144 from the angular position of the crankshaft 100. The angular position of the rotor 150 is used in the vector control actuator 500 first to calculate the amount of torque sufficient to move the piston 116B to a predetermined position before the position TDC, and then to calculate the amount of torque sufficient to move the piston past the TDC position. The first and second power levels are calculated from these torque values.

[00226] In an implementation of the ICE 24 with a decompression system, electrical power may be supplied from the capacitor 145 to the engine generator 144 already at the second level during step 804. In this case, steps 804 and 808 can be considered essentially combined into one step.

[00227] In any event, in step 810, fuel injection into the combustion chamber 120B of the ICE 24 occurs after the piston 116B has moved past the TDC position for the first time. In the implementation, the injection occurs in a range between approximately 3 degrees before TDC and 7 degrees after TDC. Since the fuel has been introduced directly into the combustion chamber 120B, fuel is immediately available in the combustion chamber 120B. Therefore, in step 812, the fuel is immediately ignited. The timing of ignition at step 812 may vary, but will occur before piston 116B passes TDC a second time. In one implementation, ignition occurs before the downward movement of piston 116B causes the outlets 136B, 138B to open when the head of piston 116B reaches the top of one of the outlets 136B, 138B. In another implementation, ignition occurs within approximately 2 degrees of rotation after injection, ranging from 0 to 12 degrees after TDC.

[00228] Often, the ICE 24 is started after performing injection and ignition steps 810 and 812 once. This will be determined at step 330 of Figure 9 for an electrical start or at step 630 of Figure 11 for an auxiliary start by determining that the crankshaft 100 speed calculated by ECU 164 from DPKV 171 has reached a minimum threshold. The supply of electrical power to the engine generator 144 is stopped at step 814 after the ICE 24 has started. In cases where the ICE 24 has not started after step 812, the sequences of Figures 9 and 11, respectively, may continue.

[00229] Figure 19 is a sequence diagram showing method steps for controlling the supply of electrical power between the power supply and the EPC. The sequence shown in Figure 19 contains many operations, some of which may be performed in a variable order, some of the operations may be performed simultaneously, and some of the operations are optional. The sequence of Figure 19 is implemented in an ICE 24 in which the motor generator 144 is electrically connected to a capacitor 145, as shown, for example, in Figure 8. The sequence may begin at step 902 when a start signal 221 is applied to transistor Q2, which is an electronic start-up power switch to turn on transistor Q2 so that electrical power is supplied from capacitor 145 to motor generator 144 via transistor Q2. As shown in Figure 8, a trigger signal 221 may be supplied to a driver 217, which in turn provides a trigger signal to a transistor Q2. The start signal 221 can be interrupted at step 904 to turn off transistor Q2 before the next step. Then, in step 906, the recharge signal 222 is applied to transistor Q1, which is an on-line electronic power switch, to turn on transistor Q1, which provides electrical power from motor generator 144 to capacitor 145 through transistor Q1 and optionally through limiting circuit 224 by current. The start signal 222 may be provided to driver 216, which in turn provides a recharge signal to transistor Q1.

[00230] In an embodiment, transistor Q2 is repeatedly turned on and off in step 902, for example, by periodically applying and resetting a start signal 221 to driver 217 to limit the supply of electrical power from capacitor 145 to motor generator 144. In an embodiment, such intermittent supply and reset the start signal 221 is executed under the control of the ECU 164 in accordance with the PWM mode.

[00231] In an implementation in which capacitor C1 and current limiting circuit 224 are provided, step 900 may precede step 902. In step 900, on signal 220 is briefly applied and then cleared to turn on transistor Q1 so that capacitor 145 begins to charge capacitor C1 while the current limiting circuit 224 protects the transistor Q1 from excess current flowing through it. As soon as voltage begins to build up in capacitor C1, operation 900 is completed, which turns off transistor Q1, and the sequence continues from operation 900 as described above.

[00232] Methods, systems, and internal combustion engines implemented in accordance with some non-limiting embodiments of the present technology may be represented as shown in the numbered paragraphs below.

[00233] Modifications and changes to the above-described implementations of the present technology can be understood by a person skilled in the art. For example, it is contemplated that the internal combustion engine 24 may be equipped with a decompression system. The decompression system can depressurize the combustion chambers 120A, 120B, thereby reducing the compression forces that must be overcome by the engine generator 144 in steps 326 and 626 described above. Thus, it is contemplated that by providing a decompression system, the engine generator 144 can be even smaller and lighter, reducing the size and weight of the capacitor 145 accordingly. Also, if a decompression system is provided, the sequence of Figure 18 may be altered by supplying electrical power to the motor generator at a higher, second level starting at step 804. The above description is by way of example and not limitation. Thus, the scope of the present technology should not be strictly limited by the scope of the attached claims.

Claims (36)

1. A method for starting an internal combustion engine (ICE) having a crankshaft and an electric rotary device (EPU), functionally connected to the crankshaft, the method includes: determination of the absolute angular position of the crankshaft, the absolute angular position of the crankshaft is related to the angular position of the EPU rotor; the supply of electrical power to the EPU at the first level to rotate the crankshaft; and the supply of electrical power to the EPU at the second level is greater than at the first level, when the EPU rotor reaches a given angular position. 2. A method according to claim 1, further comprising: calculation of the first level of electric power supply, so that the EPU generates sufficient torque to rotate the crankshaft until the rotor reaches a given angular position; and calculation of the second level of electric power supply so that the EPU generates sufficient torque to rotate the crankshaft after a given angular position of the rotor. 3. The method according to claim 2, in which: the calculation of the first level of electric power supply includes the use of vector control of the supply of electric power at the first level, taking into account the preliminary determination of sufficient torque to rotate the crankshaft until the rotor reaches a predetermined angular position; and the calculation of the second level of electric power supply includes the use of vector control of the electric power supply at the second level, taking into account the preliminary determination of sufficient torque to rotate the crankshaft after a given angular position of the rotor. 4. The method of claim 1, further comprising supplying power to an absolute position sensor used to determine the absolute angular position of the crankshaft when the engine is stopped. 5. The method of claim 4, further comprising supplying power to the absolute position sensor while the crankshaft is rotating. 6. The method according to any one of claims. 1-5, further comprising gradually increasing the supply of electrical power to the EPU from the initial level to the first level before supplying electrical power to the EPU at the second level. 7. A method according to any one of claims. 1-5, where the absolute angular position of the crankshaft is additionally related to the position of the piston in the combustion chamber of the internal combustion engine in relation to the position of the top dead center (TDC) of the piston. 8. The method according to claim 7, wherein: the supply of electrical power to the EPU at the second level begins when the piston reaches a predetermined position before the TDC position; and the method further includes injecting fuel into the combustion chamber of the internal combustion engine when the piston passes the TDC position for the first time, and igniting the fuel in the combustion chamber. 9. The method according to claim 8, further comprising determining the first level of electrical power supplied to the EPU from the initial angular position of the crankshaft. 10. The method according to claim 9, wherein the initial angular position of the crankshaft is the position of the crankshaft when the engine is stopped. 11. The method of claim 9, wherein the original angular position is a range of 80 to 100 degrees before the TDC position. 12. The method of claim. 8, where the supply of electrical power to the EPU until the piston reaches a predetermined position before the TDC position causes the displacement of gases from the combustion chamber. 13. The method of claim 12, wherein the predetermined position before the TDC position is determined in accordance with the configuration of the ICE outlets. 14. The method of claim 8, wherein the predetermined position before the TDC position is between 0 and 50 degrees before the TDC position. 15. The method according to claim 8, further comprising stopping the supply of electrical power to the EPU after starting the internal combustion engine. 16. The method according to claim 15, wherein the supply of electrical power to the ESP is stopped when the crankshaft speed reaches a minimum threshold. 17. The method of claim 8, wherein the fuel is ignited before the piston passes the TDC position a second time. 18. The method of claim 8, wherein fuel is injected into the combustion chamber when the piston position is 3 degrees before the TDC position to 7 degrees after the TDC position. 19. The method of claim 8, wherein fuel ignition occurs when the piston is in the range of 0 to 12 degrees after the TDC position, fuel ignition occurs after fuel injection. 20. The method of claim 8, wherein the ignition occurs before the piston reaches the top of the exhaust port in the combustion chamber of the internal combustion engine. 21. The method according to claim 8, wherein: the first level of supply of electrical power is calculated so that the EPU generates sufficient torque to rotate the crankshaft until the piston reaches a predetermined position before the TDC position; and the second level of electrical power supply is calculated so that the EPU generates enough torque for the piston to move past the TDC position. 22. The method according to any of paragraphs. 1-5, where determining the absolute angular position of the crankshaft includes recognizing the absolute angular position of the crankshaft. 23. The method according to any of paragraphs. 1-5, additionally including: recognition of the absolute angular position of an internal combustion engine component rotating synchronously with the crankshaft, while the component rotating synchronously with the crankshaft is selected from the EPU rotor, fuel pump, oil pump, water pump, camshaft and balance shaft; and calculating the absolute angular position of the crankshaft based on the detected absolute angular position of the ICE component rotating synchronously with the crankshaft.

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