JP4709902B2 - Fuel injection system for internal combustion engines - Google Patents

Description

    The present invention relates to a fuel injection system for an internal combustion engine.

  Most internal combustion engines in automobiles currently use a fuel injection system to supply fuel to the combustion chamber of the engine. The fuel injection system replaces early carburetor technology because it provides greater control over fuel delivery and allows the engine not only to improve the overall efficiency of the engine, but also to meet emissions control goals. It became so.

  Currently used injectors are pulse width modulated. This means that each injector operates for a selected period during each cycle of the engine, and the length of time that the injector is open determines the amount of fuel that is expelled into the combustion chamber during that cycle. In general, such a pulse width modulated fuel injection system can be operated for a predetermined period of time under the control of an electronic controller with a fixed pressure or a substantially constant known fuel supply. Use an on-off valve. As a result of such a combination of known pressure and variable but controlled opening time, a known amount of fuel is injected into the combustion chamber of the engine.

  The above approach is also taken for all gasoline injection systems (both port and direct injection systems) and the new state-of-the-art high pressure "common rail diesel injection systems. The latest common rail direct injection diesel fuel injection systems are cylinders Multiple injection pulses are sometimes used to improve fuel dispersion and improve combustion results within, but each of these pulses is of variable time (much shorter than a single pulse early fuel injection system) The controller sets the injector open time during each pulse in order to accurately control the amount of fuel delivered (though time), so all prior art systems include pumps, pressure regulators , And injectors (which function effectively as on-off valves), and elaborate electronics that control the open time of each injector The injectors used in the fuel injection system are very accurate and quick in their response (rather than the early fuel injectors that were slow and inevitable in reproducibility) Modern injectors can open and close in less than 1 millisecond.

  While the sophisticated and highly developed fuel injection systems currently available are ideal for use in automotive internal combustion engines, there are many other uses for internal combustion engines that are not suitable and expensive. Exists. For example, small single-cylinder low-power engines used in lawn mowers, chainsaws, small generators, mopeds, scooters, etc., are manufactured with very strict cost targets and have low output so that sophisticated fuel injection systems There is no room to cover the cost and power needed to operate the fuel pump that provides the pressurized fuel required by the sophisticated fuel injection systems available. To date, such small engines have used conventional carburetor technology. Now, however, such small engines face the same emission regulations as automobile engines and must be improved in a way that meets emission targets. Therefore, there is a need for an inexpensive and simple system for fuel injection for such small engines.

  The present invention, in a first aspect, combusts together in a variable volume combustion chamber, an intake system for exhaling supply air to the combustion chamber, an exhaust system for relaying combustion gas from the combustion chamber to the atmosphere, and the combustion chamber A fuel injection system for discharging the fuel into the air supply so that the fuel injection system functions as a positive displacement pump and dispenses a fixed amount of fuel for each operation of the injector And a controller that controls the operation of the fuel injector, wherein the fuel injector is operated multiple times by the controller in each of at least a majority of the engine cycle, and the engine speed and / or By increasing the number of fuel injector operations per engine cycle in response to an increase in load, the controller can control the amount of fuel delivered per engine cycle. And the controller reduces the amount of fuel delivered per engine cycle by reducing the number of fuel injector operations per engine cycle in response to a decrease in engine speed and / or load An internal combustion engine is provided.

In the second aspect of the present invention,
A variable volume combustion chamber;
An intake system for exhaling supply air to the combustion chamber;
An exhaust system for relaying combustion gases from the combustion chamber to the atmosphere;
A fuel injection system for exhaling fuel into the supply air for combustion together in a combustion chamber, the fuel injection system comprising:
A plurality of fuel injectors, each functioning as a positive displacement pump and dispensing a fixed amount of fuel with each actuation of the injector;
At least a first fuel injector of the plurality of fuel injectors dispenses a first set amount of fuel different from a second set amount dispensed by at least the second fuel injector of the plurality of fuel injectors. When,
A control device for controlling the operation of each of the plurality of fuel injectors;
An internal combustion engine comprising:
The fuel injector is actuated multiple times by the controller in each of at least most of the engine cycle,
In response to an increase in engine speed and / or load, the controller increases the amount of fuel delivered per engine cycle by increasing the number of fuel injector operations per engine cycle;
An internal combustion engine in which the controller reduces the amount of fuel delivered per engine cycle by reducing the number of actuations of the fuel injector per engine cycle in response to a decrease in engine speed and / or load. Provided.

In a third aspect, the present invention provides:
A variable volume combustion chamber;
An intake system for exhaling supply air to the combustion chamber;
An exhaust system for relaying combustion gases from the combustion chamber to the atmosphere;
A fuel injection system for exhaling fuel into the air supply to burn together in the combustion chamber;
A fuel injection system comprising:
A fuel injector that functions as a positive displacement pump and dispenses a fixed amount of fuel for each operation of the injector;
A control device for controlling the operation of the fuel injector;
An internal combustion engine comprising:
In each of at least most of the engine cycle, the fuel injector is actuated multiple times by the controller,
In response to an increase in engine speed and / or load, the controller increases the amount of fuel delivered per engine cycle by increasing the number of actuations of the fuel injector per engine cycle;
In response to a decrease in engine speed and / or load, the controller reduces the amount of fuel delivered per engine cycle by reducing the number of fuel injector operations per engine cycle;
The fuel injector
A housing in which a fuel chamber is formed;
An electric coil;
A piston that slides axially in the lumen of the housing by the action of an electrical coil that pushes fuel out of the fuel chamber, sliding between two end stops that ensure that the piston moves a set distance with each actuation. An internal combustion engine is provided comprising a moving piston.

In a fourth aspect, the present invention provides:
A variable volume combustion chamber;
An intake system for exhaling supply air to the combustion chamber;
An exhaust system for relaying combustion gases from the combustion chamber to the atmosphere;
A fuel injection system for exhaling fuel into the supply air so as to burn together in a combustion chamber, the fuel injection system comprising:
A plurality of fuel injectors each functioning as a positive displacement pump and dispensing a fixed amount of fuel for each operation of the injector, wherein at least a first fuel injector of the plurality of fuel injectors A plurality of fuel injectors configured to dispense a first set amount of fuel different from a second set amount dispensed by at least the second fuel injector of the fuel injectors;
An internal combustion engine comprising: a controller for controlling the operation of the fuel injector;
In each of at least most of the engine cycle, the fuel injector is actuated multiple times by the controller,
In response to an increase in engine speed and / or load, the controller increases the amount of fuel delivered per engine cycle by increasing the number of actuations of the fuel injector per engine cycle;
In response to a decrease in engine speed and / or load, the controller reduces the amount of fuel delivered per engine cycle by reducing the number of fuel injector operations per engine cycle;
Each fuel injector
A housing in which a fuel chamber is formed;
An electric coil;
A piston that slides axially in the lumen of the housing by the action of an electrical coil that pushes fuel out of the fuel chamber, sliding between two end stops that ensure that the piston moves a set distance with each actuation. An internal combustion engine is provided comprising a moving piston.

In a fifth aspect, the present invention provides:
A variable volume combustion chamber;
An intake system for exhaling supply air to the combustion chamber;
An exhaust system for relaying combustion gases from the combustion chamber to the atmosphere;
A fuel injection system for exhaling fuel into the supply air so as to burn together in a combustion chamber, the fuel injection system comprising:
A fuel injector that functions as a positive displacement pump and dispenses a fixed amount of fuel for each operation of the injector;
An internal combustion engine including a control device for controlling the operation of the fuel injector,
In each of at least most of the engine cycle, the fuel injector is actuated multiple times by the controller,
In response to an increase in engine speed and / or load, the controller increases the amount of fuel delivered per engine cycle by increasing the number of actuations of the fuel injector per engine cycle;
In response to a decrease in engine speed and / or load, the controller reduces the amount of fuel delivered per engine cycle by reducing the number of fuel injector operations per engine cycle;
The fuel injector includes a piston that is mechanically driven by a cam surface, the fuel injector is actuated by a biasing spring and is displaceable by the cam surface, and fuel is introduced into the fuel chamber of the fuel injector by unidirectional movement of the piston. And the movement of the piston in the opposite direction pushes the fuel out of the fuel chamber, the cam surface contains multiple cam lobes, each of which can drive the piston during each engine cycle, how much during each engine cycle The control device controls whether the number of cam lobes cause the piston to push fuel out of the fuel injector,
The fuel injector includes a fuel outlet through which fuel is pushed out of the fuel chamber by a piston and a fuel inlet through which fuel is introduced into the fuel chamber, and the fuel injector further directs fuel from the fuel inlet into the fuel chamber. A one-way inlet valve operable to prevent backflow of fuel from the fuel chamber to the fuel inlet while flowing in, and prevents backflow of fuel from the fuel outlet to the fuel chamber while flowing fuel from the fuel chamber to the fuel outlet A one-way outlet valve operable to
The one-way inlet valve can be disabled by the controller, allowing back flow of fuel from the fuel chamber to the fuel inlet when inoperable, and piston movement when the first one-way valve is inoperative Only works to draw fuel from the fuel chamber into the fuel chamber and then drain the fuel back from the fuel chamber to the fuel inlet,
An internal combustion engine is provided.

In a sixth aspect, the present invention provides:
A variable volume combustion chamber;
An intake system for exhaling supply air to the combustion chamber;
An exhaust system for exhaling supply air to the combustion chamber;
An exhaust system for relaying combustion gases from the combustion chamber to the atmosphere;
A fuel injection system for exhaling fuel into the supply air so as to burn together in a combustion chamber, the fuel injection system comprising:
A plurality of fuel injectors each functioning as a positive displacement pump and dispensing a fixed amount of fuel for each operation of the injector, wherein at least a first fuel injector of the plurality of fuel injectors A plurality of fuel injectors configured to dispense a quantity of fuel different from at least the second fuel injector of the fuel injectors;
A control device for controlling the operation of each of the plurality of fuel injectors,
In each of at least most of the engine cycle, the fuel injector is actuated multiple times by the controller,
In response to an increase in engine speed and / or load, the controller increases the amount of fuel delivered per engine cycle by increasing the number of actuations of the fuel injector per engine cycle;
In response to a decrease in engine speed and / or load, the controller reduces the amount of fuel delivered per engine cycle by reducing the number of fuel injector operations per engine cycle;
The fuel injector includes a piston that is mechanically driven by a cam surface, the fuel injector is actuated by a biasing spring and is displaceable by the cam surface, and fuel is introduced into the fuel chamber of the fuel injector by unidirectional movement of the piston. Is pulled and fuel is pushed out of the fuel chamber by movement in the opposite direction of the piston, the cam surface includes a plurality of cam lobes, each of which can drive the piston during each engine cycle, and during each engine cycle The controller controls how many cam lobes cause the piston to push fuel out of the fuel injector,
Each fuel injector includes a fuel outlet through which fuel is pushed out of the fuel chamber by a piston and a fuel inlet through which fuel is introduced into the fuel chamber, wherein each fuel injector is further from the fuel inlet into the fuel chamber. A first one-way inlet valve operable to prevent back flow of fuel from the fuel chamber to the fuel inlet while injecting fuel, and from the fuel outlet to the fuel chamber while allowing fuel to flow out of the fuel chamber to the fuel outlet; A second one-way outlet valve operable to prevent fuel backflow;
The one-way inlet valve of each fuel injector can be disabled by the controller, allowing back flow of fuel from the fuel chamber to the fuel inlet when inoperable and the piston when the first one-way valve is inoperative An internal combustion engine is provided in which the movement of the engine serves only to draw fuel from the fuel inlet into the fuel chamber and then back-flow the fuel from the fuel chamber to the fuel inlet.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  Referring initially to FIG. 1, one can see an internal combustion engine 10 with a piston 12 comprising a cylinder 11 that reciprocates therein, the cylinder 11 and the piston 12 defining a combustion chamber 13 therebetween. it can. Piston 12 is connected to crankshaft 15 by connecting rod 14, which in turn is connected to camshaft 16. A mechanism (not shown), such as a push rod type mechanism, is used between the camshaft 16 and the two poppet valves 17 and 18, which are engine exhaust and inlet valves. The camshaft 16 drives the inlet valve 18 and the discharge valve 17 to open in time with the movement of the piston 12 in the cylinder 11, and the return spring biases the poppet valves 17 and 18 back to their valve seats. . The engine 10 is a simple engine, such as a single cylinder engine of a lawn mower or other garden equipment.

  The engine 10 has a fuel injection system that includes a fuel injector 19 configured to expel fuel into an inlet passage 20 upstream of the inlet valve 18. A throttle valve 21 is disposed in the inlet passage 20 in order to restrict the flow of the supply air into the combustion chamber 13. A sensor is connected to the throttle valve 21, and a signal indicating the rotational position of the throttle valve 21 and thus the engine load is fed back to the electronic control unit 23 via the line 22. The ECU 23 also receives the timing signal generated by the camshaft sensor 25 (which can alternatively be replaced by a crankshaft sensor) via line 24. Considering the timing signal generated by the sensor 25 and the load signal generated by the sensor attached to the throttle valve 21, the ECU 23 generates a control signal, which is relayed to the injector 19 via the line 26 and injected. The operation of the device 19 is controlled.

  A first embodiment of the injector 19 is shown in FIG. The injector 19 has a fuel inlet 30 in which a filter 31 is arranged to remove impurities from the fuel before the fuel enters the injector body. The injector body 32 has a cavity 33 in which a stack 34 of piezoelectric elements is disposed. The fuel introduced by the inlet 30 passes through the stack 34 along the passage 35. A flexible diaphragm 36 abuts the free end of the stack 34, and the diaphragm 36 incorporates a one-way valve 37 that aligns with a passage 35 through the stack 34. A portion 38 of the cavity 33 is defined by a flexible diaphragm 36 that leads to a fuel outlet passage 39 that is opened and closed by a one-way reed valve 40. Downstream of the reed valve 40 is a high voltage electrostatic charging electrode 41 through which an aperture that allows fuel to pass therethrough. Downstream of the electrode 41 is a fuel outlet disk 42 having a plurality of fuel outlet orifices defined therein. Because electrode 41 and disk 42 together apply a charge to the fuel passing through the injector, this disk 42 is also charged to function as an electrode, which facilitates atomization of the fuel.

  A simple gravity fed fuel delivery system (not shown) relays fuel from a fuel tank (not shown) to the fuel inlet 30 which is then filtered by a filter 31. The fuel is then drawn into and discharged from the fuel injector of FIG. 2 by expansion of the stack 34 of piezoelectric elements. When a voltage is applied to the piezoelectric elements of the stack 34, they expand, which increases the length of the stack 34 and causes the flexible diaphragm 36 to be pressed. When this occurs, the one-way valve 37 closes and the fuel in the portion 38 is pushed out of the portion 38 by the diaphragm 36 that bends under the action of the stack 34. The one-way valve 40 is opened so that fuel can be discharged from the portion 38, and the discharged fuel then passes through the orifice of the charging electrode 41 and then through the orifice of the fuel outlet disk 42 to the air inlet. Enter the passage 20 (shown in FIG. 1). The fuel passing through the electrode 41 and the disk 42 receives an electrostatic charge, which helps to atomize the fuel discharged from the orifice of the fuel outlet disk 42.

  Once the voltage is removed from the stack 34 of piezoelectric elements, the stack 34 returns to its original length and the elastic flexible diaphragm 36 returns to its original position, thereby increasing the volume of the injector cavity portion 38. Increase. This in turn causes the one-way valve 40 to close and seals the portion 38 from the fuel outlet while the one-way valve 37 opens so that fuel can flow into the passage 35 and fill the cavity 38. The cavity 38 can then be filled with fresh fuel in preparation for the next injection of fuel into the air inlet passage 20.

  In FIG. 2 it can be seen that the control line 26 is electrically connected to the stack 34 of piezoelectric elements and also to the high voltage electrostatic charging electrode 41.

  The fuel injector of FIG. 2 operates as a positive displacement pump that dispenses the same amount of fuel each time the injector is actuated. The amount of fuel dispensed by the injector is constant for each operation. This is significantly different from an injector that functions as an on-off valve that controls the flow of fuel passing therethrough, and the fuel supplied to the injector is supplied from a pressurized source. Such injectors control the amount of fuel expelled by varying the injector opening time. In the injector of the present invention, there is no such variation in the open time, instead it functions as a positive displacement pump and discharges a set amount of fuel per actuation.

  A second type of fuel injector suitable for operation as the injector 19 of FIG. 1 is shown in FIG. The injector 19 discharges a set amount of fuel each time it operates, and the injector itself operates as a pump that reliably discharges a certain amount of fuel from it, and the volume remains constant before and after each operation of the injector. Maintained. The injector 19 is a simple positive displacement type with two one-way check valves that ensure the correct flow path for fluid flowing into and out of the injector, and a solenoid driven piston that slides in a cylinder that acts as a constant volume unit. It is a pump. The injector serves as both a pump unit and a flow measurement unit. The flow rate expelled by each pulse is a fixed geometry regardless of the differential pressure across the injector, and the injector becomes insensitive to variations in the pressure in the suction passage 20 of the suction manifold.

  The injector of FIG. 2 has a fuel inlet passage 50 connected to a fuel tank (not shown) for receiving fuel by a simple gravity supply configuration (not shown). A spring-biased one-way valve 51 controls the flow of fuel from the inlet passage 50 into the fuel chamber 52 of the injector. A spring-biased one-way valve 53 controls the outflow of fuel from the cavity 52 to the fuel outlet tube 54 through which the fuel is aspirated (directly or via a conduit to a remote injection nozzle). It can be discharged into the passage 20.

  The piston 55 is slidably disposed in the injector body. It is actuated by a biasing spring 56 and is surrounded by a solenoid 57. An end plate 58 is connected to the piston 55 and extends radially outward from the piston over the entire end face of the solenoid 57. Solenoid 57 is connected to ECU 23 by line 26.

  The piston 55 starts from a state in which the piston 55 is biased to its lowest point (that is, the point where the fuel chamber 52 has its maximum volume) by the biasing spring 56, and fuel for injection is injected into the fuel chamber 52. Next, the excitation of the solenoid 57 causes the plate 58 to be attracted and contact or substantially contact the solenoid 57. The piston 55 moves upward against the force of the biasing spring 56 and reduces the volume of the fuel chamber 52. As a result, the fuel is reliably discharged from the fuel chamber 52, the one-way valve 53 is opened, and the piston 55 can push the fuel out of the fuel outlet 54 from the fuel chamber 52.

  Once the solenoid 57 is demagnetized, the biasing spring 56 pushes the piston 55 downward, causing the plate 58 to move away from the solenoid 57. The downward movement of the piston 55 increases the volume of the fuel chamber 52, which has the effect of closing the one-way valve 53 and opening the one-way valve 51. The moving piston 55 draws fuel from the fuel inlet 50 into the fuel chamber 52 and completely fills the fuel chamber 52 in preparation for the next dispensing of fuel.

  The injector is configured such that the piston 55 moves a set distance for each actuation. The piston 55 moves between the two end stops. Therefore, each time the injector is operated, the piston 55 discharges a set amount of fuel, and the set amount of fuel is dispensed from the fuel outlet 54. The amount of fuel dispensed by the injector is constant for each operation.

  A typical fixed amount of fuel dispensed by the injector is generally between 0.1 μl and 1 μl, but usually less than 0.5 μl. The injector can usually operate at a frequency of 300 Hz to more than 1 KHz, preferably between 1 KHz and 2 KHz. Such amounts and operating frequencies are suitable for many engine displacements in the small engine market.

  The operating principle of the injector of FIG. 3 is to discharge a geometrically fixed amount of fuel with each operating pulse. Since engines with different displacements and outputs have different fuel consumption rates, the pulse volume needs to be optimized to best fit the individual engine.

  In order to produce the injector of FIG. 3 in large quantities and therefore at the lowest possible price, it is advantageous to have one size injector that is compatible with a wide range of different sized engines. To accomplish this, the stroke of the injector piston can be easily adjusted by mounting shims during manufacture to provide the desired pulse volume for the particular application of each injector.

  FIG. 3 shows an injector that is free of shims and results in the maximum possible stroke of the piston 55 with each pulse. The same injector with shim 59 attached is shown in FIG. The use of shims 59 reduces the stroke of the piston 55 and allows the injector to be optimized for smaller displacement engines. The discharge rate of the injector is still geometrically fixed and can be reproduced from operation to operation during its operation.

  The important feature is that the amount of ejector of the injector is always a constant geometric amount, and the accuracy of fuel discharge is ensured when used in the engine. However, the use of shims allows for cost-effective mass production of substantially identical injector units that can be easily configured to fit a wide range of engines at the end of manufacturing.

  FIG. 5 shows a fourth embodiment of the injector according to the present invention. As in the embodiment of FIGS. 3 and 4, the injector includes a piston 500 that is movable by the action of a biasing spring 501 and a solenoid 502. The piston 500 can slide in the fuel chamber 503. The one-way inlet valve 504 allows fuel to be drawn into the fuel chamber 503 from the fuel inlet 505, but prevents fuel from being discharged from the fuel chamber 503 to the fuel inlet 505. The one-way outlet valve 506 allows fuel to be discharged from the fuel chamber 503 to the fuel outlet 507, but prevents fuel from being drawn into the fuel chamber 503 from the fuel outlet 507.

  Unlike the embodiment of FIGS. 3 and 4, the injector of FIG. 5 uses a spring 501 to force the piston 500 to discharge fuel from the fuel chamber 503 to the fuel outlet 507 and uses a solenoid 502. The piston is then moved to draw fuel into the fuel chamber 503 (this is the reverse of the embodiment of FIGS. 3 and 4). Piston 500 has an end plate 508 that extends radially outward from piston 500 over the entire end surface of solenoid 502. The amount of fuel discharged, the spring constant, etc. are the same as or similar to those described above.

  FIG. 6 shows a variation of the embodiment of FIG. 5 in which a shim 509 is provided in the fuel chamber 503 to limit the displacement of the piston 500 and thereby set the amount of fuel dispensed with each actuation of the injector. Indicates. The shim 509 has an aperture that penetrates the fuel chamber 503 so as to communicate with the one-way outlet valve 506 and the fuel outlet 501. As described above, the use of shims allows for a manufacturing process that produces substantially identical injector units that differ in the amount of fuel output by selecting an appropriately sized shim.

  4 and 6, the illustrated shims 59, 509 are secured to the injector housing, but instead of or in addition to the illustrated shims 59, 509, the shims Can be attached to either.

  FIG. 7 shows an injector 700 in which a piston 701 is located in the center of a solenoid 702 and a back iron 703. The back iron 703 is designed to direct the flow of magnetic flux around the solenoid winding. The piston 701 is pulled to engage with the back iron 703 when the solenoid 702 is excited. The piston spring 704 pushes the piston 701 away from the back iron 703 when the solenoid is demagnetized. A fuel inlet check valve 705 is disposed in a fuel passage that penetrates the piston 701. The fuel passage allows fuel flow to the fuel chamber 706 via the piston. Fuel is dispensed from the fuel chamber 706 to the fuel outlet 707 via the outlet check valve 708. In the injector of FIG. 7, it is advantageous that the movement of the piston 701 assists the operation of the inlet check valve 705 as shown in FIGS. 8a) -d). FIG. 8a shows the piston 701 in its bottom stop position. The mass of the check valve 705 ball helps its own spring close the inlet check valve 705 and thus seal the fuel chamber 706.

  As shown in FIG. 8 b), when the solenoid coil 702 is excited by current, the piston 701 is pulled up by the magnetic flux flowing in the back iron 703. In this motion, the inertia of the inlet check ball ensures that the ball is in contact with its seat, which ensures a tight seal of the inlet valve 705 so that all fluid discharged from the fuel chamber 706 can be Ensure outflow through stop valve 708. As shown in FIG. 8c), when the piston 701 reaches its upper position and the pulse volume of fuel is discharged, the piston 701 stops rapidly due to its end stop. However, the ball of the inlet check valve 705 continues to rise due to its own moment, causing the inlet check valve 705 to open. At this time, the solenoid 702 is demagnetized, and the piston spring 704 pushes the piston 701 downward.

  As shown in FIG. 8d), the piston 701 is driven by its spring and moves downward. The ball of the inlet check valve 705 is delayed not only due to its mass inertia but also due to the force of fuel flow, and in this state, when the piston 701 continues to descend, the fluid can easily flow into the fuel chamber 706. To fill and fill it.

  When the piston 701 reaches its bottom stop, it quickly stops again and the ball of the inlet check valve 705 is again brought into contact with its seat due to its moment, as shown in FIG. 8a).

  In this way, opening and closing of the inlet check valve 705 is facilitated by the movement of the piston 701. This allows the injectors to be driven at a higher frequency than would otherwise be possible.

  FIG. 9 shows a detailed cross-sectional view of the injector of FIGS. 7 and 8a) to 8d). It can be seen that the inlet check valve 705 includes a ball 710 and a spring 711.

  The spring constant of the spring 711 of the inlet check valve 51 is generally selected in the range of 0.4 N / mm to 1.75 N / mm in order to lift the check ball from its seat during the intake stroke, The displacement of the piston is generally 50 to 150, for example 100 μm. Inlet check valve 51 is illustrated in FIG. 11 as including balls 710 and 711.

  By providing an inlet check valve in the fuel passage of the piston, it is possible to dispense with a check valve spring as shown in FIGS. 10a) to 10d) and FIG. The inlet check valve 7000 includes a ball 7001 movable within the cage 7002 (see FIG. 12). The cage 7002 allows fuel flow, but keeps the ball 7001 trapped in place. The function of valve 7000 is exactly the same as described for valve 705, but depends on the mass inertia of ball 7001 as the only means for opening and closing valve 7000. This can be seen in FIGS. 10a) to 10d), in which the movement of the ball and the movement of the piston are indicated by arrows as well as the direction of fluid flow. In FIG. 10a), movement of ball 7001 causes the valve to close. In FIG. 10b), when the piston descends, the mass inertia of the ball 7001 raises the ball away from the seat (the fluid pressure difference before and after the valve also helps). In FIG. 10d) it can be seen that the cage 7002 stops the ball 7001 from moving too far from its seat during the lowering of the piston. By using the valve without a spring, cost and assembly time are reduced. A disc can be used in place of the ball and / or this is shown in FIG. 13 where the disc is movable within the cage 7011 (this valve functions in the manner described above for valve 7000). The use of a disk can reduce the amount of fluid trapped in the fluid passage above the valve in the piston and reduce the sensitivity of the configuration to gas traps.

  The control of the injector of the present invention is now quite different from the control of prior art injectors, as shown in FIGS. 14, 15 and 16a) to 16d).

  In FIG. 14, a graph of control signals used to control a prior art injector can be seen. The operating mode used is called pulse width modulation control. The solid line shows a pulse of a selected width, which corresponds to the open period of a conventional fuel injector. The dashed line indicates the other larger pulse width, i.e. the larger open period of the prior art prior art injector. With the set supply pressure, the control of the pulse width provides an accurate control of the amount of fuel delivered by the fuel injector.

  Proceeding to FIG. 15, FIG. 15 shows control signals generated by the ECU 23 to control the fuel injector 19 of the present invention. Instead of pulse width modulation, a kind of control called pulse count injection is used. It can be seen that six types of pulses are indicated by solid lines. These are pulses for the discharge of charged fuel for a single cycle of engine operation, i.e. one combustion event in the combustion chamber 13. Each pulse represents one operation of the injector 19. As explained above, the injector 19 expels a set amount of fuel per actuation, so the total amount of fuel expelled for combustion controls the number of times the injector is activated for a particular engine operating cycle. Controlled by. In the case indicated by the solid line, the injector 19 is actuated six times to expel a total amount of fuel equal to six times the set amount expelled by the injector in each actuation. This fuel is discharged into the air inlet passage 20 in order to mix with the air discharged into the combustion chamber 13. While the inlet valve 18 is closed, the first actuation of the injector 19 takes place, but by the last actuation of the injector 19, the valve may be open or at least be starting to open.

  In FIG. 15, the dashed pulse indicates that more fuel can be expelled during the operating cycle by operating the injector more times. FIG. 15 shows a possible total pulse count of 10 pulses resulting in a total fuel discharge of 10 times the set amount delivered by the injector at each actuation.

  Further details are shown in FIGS. 16a) to 16e). FIG. 16 a) shows the camshaft or crankshaft signal that the ECU 23 receives on line 24. The pulse indicated in the signal indicates the rotational position of the crankshaft or camshaft. It can be seen that the ECU 23 times the control signal itself so that its own pulse is synchronized with the timing signal pulse shown in FIG. 16a). Indeed, as shown in FIGS. 16b) to 16e), it is the timing signal pulse of FIG. 16a) that triggers the ECU 23 to generate its own control pulse. Alternatively, the engine cycle can be started with only one timing pulse from the crankshaft or camshaft sensor, and a pulse of the timing signal can be generated within the ECU 23.

  FIG. 16b) shows full load operation. Therefore, in each engine cycle (one engine cycle occurs between the dotted lines in the figure), the ECU generates a control signal including 13 pulses for operating the injector 19 13 times as shown in FIG. 16b). This represents the maximum amount of fuel that can be expelled for combustion in the combustion chamber 13.

  FIG. 16c) shows the control signals generated in each engine cycle for partial load operation. In this case, the control signal for each cycle includes seven pulses that actuate the injector 19 seven times in each engine cycle. Therefore, the amount of fuel discharged in each engine cycle is 7/13 of the total amount of fuel discharged in full load operation.

  FIG. 16d) shows the control signal generated by the ECU during idle operation, that is, when a minimum amount of fuel is discharged in each engine cycle. FIG. 16d) shows that the injector 19 operates only 4 times in each engine cycle.

  Finally, FIG. 16e) shows an exceptional condition of engine start in which a rich mixture of fuel and air has been expelled into the combustion chamber 13 to allow the engine to start. A 17 pulse count is shown for each engine cycle, which means that the injector 19 operates 17 times during each engine cycle when the engine is started. The total fuel discharged is 17 times the set amount that the injector discharges with each operation.

  It will be appreciated that the engine described above eliminates the need for a separate fuel pump and pressure regulator and dramatically simplifies ECU functionality. The fuel injection system includes a simple control system that counts the desired number of fuel pulses to the engine for its precise operation. This does not provide the degree of control possible with prior art systems (i.e. the total amount of fuel delivered cannot be continuously varied within a certain range, but at a set interval or a set quantity unit. However, this is sufficient for simple engines such as those used in lawn mowers. In other words, the control possible with pulse count injection more roughly controls the amount of fuel delivered to the engine, but this is sufficient when a simple engine is involved.

  As mentioned above, the fuel expelled from the injector can be sent to a simple and simple orifice or nozzle (see FIG. 2), or pressure spray nozzles (FIGS. 17, 18, 19, 20a) to 20d), and 21a. To 21d)) or an atomizing device such as an electrostatic charging unit (shown in FIG. 2). The injector (or pulse unit) can be tightly coupled to the atomization unit or arranged at some distance somewhere else in the engine (ie the embodiment of FIG. Can have a fuel outlet leading to a distance from the injector shown).

The amount of fuel exhaled by the fuel injector depends to some extent on the size of the engine and the range of engine operating conditions. Generally, injector spit 0.8 mm ³ from 0.05 mm ³ per pulse. If the 1 pulse per 0.01 mm ³ assuming a range of 0.5 mm ^3, the total amount ejected in each engine cycle becomes generally between 0.5 10.0 mm ^3. If this is the case, the number of pulses required for correct engine operation varies from 5 to 10 pulses per engine cycle for engine idle and from 20 to 50 pulses per cycle for full load operation.

  Since the injector controls the amount of fuel delivered to itself, there is no need for a controlled fuel supply pressure, which is a problem due to pressures that fluctuate due to different heads of fuel as the fuel level decreases. This means that the fuel can be fed directly into the injector via the gravity supply system without causing Alternatively, a simple low pressure fuel pump can be used, as is often used in carburetors. The only requirement is that enough fuel be expelled to the injector so that it can fill itself in preparation for the next pulse.

  The total amount of fuel delivered to the engine in each cycle (every 2 strokes for a 2-stroke engine or every 4 strokes for a 4-stroke engine) is the amount of fuel delivered by each operation of the injector and the injector is operating in that cycle. It is determined as multiplication of the number of times. The engine management system can simply be configured to deliver a different number of pulses with its control signal, as measured by the sensor 21, depending on the load demand required of the engine. Thus, a very small number of I.D. values comparing the throttle position measured by sensor 21 (eg, throttle position potentiometer) with a look-up table that shows the number of pulse counts required for that throttle position. C. A very simple electronic control unit can be built from the chip, and then the ECU is triggered by the timing signal on line 24 to generate pulses and counts the number of pulses until the correct number of pulses is reached. The pulse injector is then stopped until the next engine cycle.

  Proceeding to FIG. 17, a throttle body 202 of an internal combustion engine is shown. The throttle body 202 includes an inlet passage portion 200 of the inlet passage 20 of FIG. The inlet passage 200 has one end 204 communicating with the engine combustion chamber 13 via the inlet valve 18 and the other end 206 generally communicating with the atmosphere via an air filter (not shown). A throttle valve 21 is disposed in the inlet passage portion 200, and a fuel injector 19 of the type shown in FIGS. 3 to 13 is provided downstream of the throttle valve 21 and between the throttle valve 21 and the inlet valve 18. .

  In the configuration of FIG. 17, the fuel dispensed from the fuel chamber 52 is dispensed to the fuel outlet 214 including the mixing chamber 218 and the atomizing nozzle 214 in the embodiment of FIG. 13. In order to help produce a fuel and charge air mixture that burns rapidly when ignited in the combustion chamber, the fuel must be effectively mixed with the charge air. Conventional carburetors and fuel injectors accomplish this by having multiple holes at the end of the injector nozzle to form a fine spray of fuel from the nozzle to the charge. The atomizing nozzle 214 of the present invention is a sonic nozzle (also known in the art as a critical flow venturi, or critical flow nozzle). The atomizing nozzle can also be an air blast nozzle.

  Sonic nozzles are often used as “fluid flow standards” because they achieve a constant volume flow, assuming that the pressure difference across them exceeds a predetermined threshold. A schematic diagram of the sonic nozzle is shown in FIG. The nozzle includes a venturi 350 that is narrowed in internal dimensions to provide a throat. The fluid upstream 352 of the venturi throat is at a higher pressure than the fluid downstream 354 of the venturi throat. The fluid flowing into the nozzle is accelerated in a narrow throat region. The velocity of the fluid in the throat approaches the speed of sound. Once this condition is realized, it goes without saying that the flow rate in the sonic nozzle remains constant even if the downstream pressure changes significantly, assuming that the pressure difference across the nozzle continues to exceed the threshold. . Therefore, in this example, a constant fuel flow rate to the supply air is achieved. Note that the sonic nozzle achieves a constant flow rate regardless of a sudden change in downstream pressure, assuming that the downstream pressure is maintained below about 85-90% of the upstream pressure.

  In the present invention, the fuel passage in the sonic nozzle 214 helps to disperse the fuel into the charge air. In fact, since the speed of the fuel passing through the throat 302 approaches the speed of sound, the nozzle 214 acts as a very efficient atomizer that breaks down the liquid fuel into atomized particulates. In general, the finer the spray of fuel in the charge air, the better the combustion process is achieved. Although the exact operation of the sonic nozzle in fuel atomization is not well understood, the passage of liquid fuel through the shock wave in the high speed region of the sonic nozzle causes very high shear stress on the liquid surface, and Cavitation bubbles are generated in the liquid, and both of these processes are thought to lead to very fine atomization of fuel and dispersion into the charge.

  The mixing chamber 218 is disposed between the outlet check valve 53 and the nozzle 226. As can be seen in the enlarged views of FIGS. 17 and 19, the throttle body 202 also includes an air bypass passage 240. This consists of a passage communicating with both the mixing chamber 218 and the region where the air is at atmospheric pressure.

  The fuel dispensed by the injector 19 passes through the mixing chamber 218 and then passes through the sonic nozzle 226. The low pressure in the inlet passage 200 also draws air through the air bypass 240. Thus, the air flows through the air bypass pipe 240 and takes in the fuel dispensed into the mixing chamber 218 by the injector 19. The air in the air bypass 240 is at a higher pressure than the air in the inlet passage 200, so that when fuel is dispensed from the nozzle 214, it causes an air flow from the passage 240 through the sonic nozzle 214 into the inlet passage 200. It is captured. Thereby, the dispensed fuel is atomized.

  FIGS. 20a) to 20d) show the operation of an “air-assisted” sonic atomizer for a port fuel injector through the engine cycle at two different load conditions of the engine.

  The injector 19 discharges fuel and controls the amount of fuel. The movement of air at the suction port produces an atomization effect. This allows each process to be fully optimized and achieves maximum effect with minimal energy.

  In FIGS. 20a) and 20c), fuel is introduced into the mixing chamber 218 during the engine cycle when the engine intake valve 18 is closed. Under these conditions (regardless of engine load), the air moves very little, so the fuel exhaled over the entire engine cycle accumulates in this chamber. When the engine intake valve 18 is opened, air is drawn into the combustion chamber 13 through the intake port. In the partial load state shown in FIGS. 20 a) and 20 b), the throttle 21 is partially closed and the air flow creates a pressure difference across the throttle 25. In the full load (large opening throttle) state shown in FIGS. 20 c) and 20 d), the air velocity at this time causes a pressure drop at the venturi throat 302.

  Due to the amount of fuel accumulated in the mixing chamber, the air flowing through the bypass passage 240 begins to cause fuel foaming, and as the air and entrained fuel flow increases in velocity to the sonic nozzle 214 (due to a reduction in cross-sectional area). High shear forces occur, leading to better atomization of the fuel as it is blown into the intake port.

  This process not only produces a sufficiently atomized fuel spray, but because the timing is coincident with the opening of the intake valve 18, the fuel is taken directly into the combustion chamber 13 and does not accumulate on the walls of the intake port. There are also advantages. This timing effect also allows the fuel into the mixing chamber 218 to be measured in the remainder of the engine cycle, and therefore does not cause problems due to insufficient atomization due to the lack of inherent atomization. Making it possible to use lower pressure injectors.

  In this way, very well atomized fuel is expelled with minimal energy usage at the best engine timing.

  Improved fuel atomization at the inlet port not only improves fuel-air mixing, thus improving the combustion process within the engine, resulting in reduced emissions and reduced fuel consumption, but also for small engines. Start-up is also easier.

  The air bypass 240 is not limited to supplying air and can alternatively be connected to a gas source that provides an alternative gas to facilitate atomization or combustion. One such example of another gas that can be used is exhaust gas from an engine (ie, exhaust gas recirculation).

  The sonic nozzle 214 can include orifices of various shapes, as shown in FIGS. 16a) to 16d). The orifice of a standard sonic nozzle is circular as shown in FIG. 16a when taken in a cross section perpendicular to the flow direction. Alternative shapes for the nozzle orifice include a linearly extending orifice as shown in FIG. 16b, a cruciform shape as shown in FIG. 16c), or alternatively a collection of small circular orifices as shown in FIG. 16d.

  FIG. 22 shows a further embodiment of the engine according to the invention, which has an electrically controlled mechanically powered injector instead of the electric injector described above.

  In FIG. 22, an internal combustion engine 80 can be seen comprising a cylinder 81 in which a piston 82 reciprocates, with the cylinder 81 and piston 82 defining a combustion chamber 83 therebetween. Piston 82 is connected to crankshaft 85 by connecting rod 84, which in turn has a camshaft (not shown) having a cam that actuates two poppet valves 87 and 88, which are the engine outlet and inlet valves, by camming. Connected to. These valves are opened and closed in synchronism with the piston 82 and the cylinder 81. A return spring (not shown) is provided to bias poppet valves 87 and 88 to seat them. The engine 80 is a simple engine, such as a single cylinder engine of a lawn mower or other garden equipment. The engine 80 has a fuel injection system that includes a fuel injector 90 configured to discharge fuel into an inlet passage 89 upstream of the inlet valve 88. A throttle valve 91 is disposed in the inlet passage 89 in order to restrict the flow of the supply air into the combustion chamber 83. A sensor is connected to the throttle valve 91 to generate a signal indicating the position of the throttle valve 91, which is supplied to the engine control unit 92 as an electrical signal.

  The fuel injection system of FIG. 22 includes a cam surface 93 provided on the peripheral surface of a wheel 94 attached to the crankshaft 85 and rotating therewith. The fuel injector 96 is driven by the cam surface 93 and is shown in more detail in FIG.

  In FIG. 23, it can be seen that the fuel injector 96 includes a fuel inlet 97 that receives fuel fed into it from a fuel tank (not shown) by a gravity supply system (not shown). The fuel flow controlled by the spring-biased first one-way valve 99 allows fuel to be delivered from the fuel inlet 97 into the fuel chamber 98. The spring-biased second one-way valve 100 controls the flow of fuel from the fuel chamber 98 to the fuel outlet 101. The fuel outlet 101 is connected to a discharge nozzle and an atomizer 90 by a fuel line 102 (see FIG. 22).

  The piston 102 is slidably mounted in the housing 103 of the injector 96 and is slidable in the fuel chamber 98. The piston 102 has a cam follower 103 that is a roller follower that is rotatably attached to one end of the piston 102. The roller follower 103 engages with and follows the cam surface 93 (see FIG. 22). The piston 102, and thus the roller follower 103, engages the cam surface 93 by a biasing spring 104 acting between the injector body 103 and a shoulder 105 provided to extend radially outward from the piston 102. It is energized to do.

  The injector 96 is also provided with a control solenoid 106, which is electrically controlled by a signal provided to a line 107 along which a control signal from the engine control unit 92 passes. The solenoid 106 can act on an override pintle 108 that includes a rod 113 that extends through the solenoid 106 and a disk 109 that extends radially outward from the rod 113 across the end of the control solenoid 106.

  During operation of the injector (starting with the piston 102 occupying a position where the fuel chamber 98 has its maximum volume and assuming that the fuel chamber 98 is completely filled with fresh fuel charge), the piston 102 is It is pushed into the chamber 98 by the action of the cam surface 93. Thus, the piston 102 drains fuel from the chamber 98 which flows out of the fuel outlet 101 and the one-way valve 100 opens to allow fuel to be dispensed from the fuel chamber 98, while the one-way valve 99 opens the fuel inlet 97. Seal from the fuel chamber 98. The fuel pushed out from the fuel chamber 98 is discharged along the fuel pipe 102, sent to the nozzle 90, and discharged as a spray into the air intake passage 89. Thereafter, the piston 102 moves according to the contour of the cam surface 93 and by the action of the biasing spring 104 so as to increase the volume of the fuel chamber 98. This has the effect of opening the one-way valve 99 while closing the one-way valve 100. The fuel is then drawn from the fuel inlet 97 into the fuel chamber 98 until the maximum amount of fuel is reached, after which the process begins again.

  In FIG. 24 it can be seen that the injector 96 interacts with the cam surface 93 and it clearly shows that the cam surface 93 includes a pulse lobe such as 110 separated by a base circle region such as 111. As can be seen, the pulse lobes typically have ridges with a radius of 0.1 to 0.5 mm greater than the base circle. In FIG. 10, it can be seen that the wheel 94 has a total of 20 pulse lobes and also has a constant radius portion 112. When the roller follower 103 engages the portion 112, the pulse injector 116 is deactivated.

  If the control solenoid 107 remains deactivated for the entire engine cycle, each cam surface pulse lobe (eg, 110) results in a volume of fuel being dispensed from the pulse injector 96. The injector 96 dispenses 20 separate fuel pulses for one complete rotation of the wheel 94. Since the height of each pulse lobe 101 with respect to the base circle is the same as all other pulse lobes, the piston 102 moves by a set amount in each operation, and the amount of fuel dispensed by the injector 96 is the injector 96. It should be understood that for all of the operations, all dispenses of fuel from the injector 96 will be the same. The operation of the injector 96 20 times for each rotation of the wheel 94 represents that the maximum amount of fuel possible is discharged into the engine during each operating cycle, such a condition being used, for example, at engine startup. The

  A control solenoid 107 allows control of the injector 96. When the solenoid 106 is energized, the pintle 108 engages the one-way valve 99, opening it and leaving it open. When the one-way valve 99 opens, the movement of the piston 102 draws fuel from the fuel inlet 97 into the chamber 98 and then pushes fuel back from the chamber 98 back to the fuel inlet 97. Fuel is not discharged from the chamber 98 through the one-way valve 100. Thus, the ECU can control the operation of the injector 96 and how many fuel pulses are delivered by the injector 96, and thus in each engine cycle (every two strokes for a two stroke engine or for a four stroke engine). The total amount of fuel delivered (every 4 strokes) can be controlled.

  In FIG. 25, instead of the injector 96 shown in FIG. 7, an injector 150 can be seen that can be used with the engine of the figure. The injector 150 includes a fuel inlet 151 that receives fuel from a fuel tank (not shown) that is pumped there by a gravity supply system (not shown). The fuel flow controlled by the spring-biased first one-way valve 153 allows fuel to be delivered from the fuel inlet 151 into the fuel chamber 152. The spring-biased second one-way valve 157 controls the flow of fuel from the fuel chamber 152 to the fuel outlet 154. The fuel outlet 154 is connected to the discharge nozzle and atomizer 90 by the fuel line 120 of FIG.

  The elastic displacement diaphragm 155 seals the fuel chamber 152. The diaphragm 155 is provided with a cam follower contact pad 156. Contact pad 156 engages and follows a cam surface (not shown). The contact pad 156 is biased by the elasticity of the diaphragm 155 and engages with the cam surface. The cam surface can change properties under the control of the ECU 92 in order to deliver a variable number of impulses to the contact pad 156. This is achieved, for example, by mounting the second control wheel 95 along the cam wheel 94 so as to be rotatable together with the cam wheel 94 and also to the cam wheel 94 under the control of the ECU. The Such a configuration of the cam wheel 94 and the control wheel 95 is shown in FIG. The control wheel 95 has a first sector 95a having a constant radius outer circumference equal to the radial distance to the top of each lobe 110 of the cam wheel 94, and a radial distance to the bottom of each base circle region 111 of the cam wheel 111. It has a second sector 95b with an outer periphery of equal constant radius. At one extreme, the second sector 95b of the control wheel 95 is aligned with all lobes and base circles of the cam wheel 94, which all act to displace the diaphragm 155. Then, as the control wheel 95 and the cam wheel 94 rotate relative to each other, the first sector 95a of the control wheel aligns with a portion of the cam lobe 110 and the base circle 111, and the greater radial height of the control wheel 95. "Overrides" the base circle 111 of the cam wheel 94, thus "inactivating" them.

  During operation of the injector 150 (assuming that the fuel chamber 152 has its maximum volume starting from the position occupied by the diaphragm 155 and that the fuel chamber 152 has been completely filled with fresh fuel charge), the diaphragm The cam 110 is bent by the action of the cam 110 to reduce the volume of the fuel chamber 152, so that the fuel is discharged from the chamber 152, flows out from the fuel outlet 154, and the one-way valve 157 is opened so On the other hand, the one-way valve 153 seals the fuel inlet 151 from the fuel chamber 152. The fuel pushed out from the fuel chamber 152 is discharged along the fuel pipe 120, sent to the nozzle 90, and discharged as a spray into the air inlet passage. The diaphragm 155 then flexes to increase the volume of the fuel chamber 152 (according to the cam surface contour and due to its own elasticity). This has the effect of opening the one-way valve 153 while closing the one-way valve 157. The fuel is then drawn from the fuel line 151 into the fuel chamber 152 until the maximum amount of fuel is reached, after which the process begins again.

  In each operating cycle of the engine, the diaphragm 155 bends so that fuel can be discharged from the fuel chamber 152 by each cam lobe operable in that cycle, and the number of operable cam lobes is determined by the ECU, for example, the control wheel described above to the cam wheel. It is selected by rotating relative to it.

  Similar to the engine of FIG. 1, the engine of FIG. 22 does not require a high pressure pump to pressurize the fuel supply source or a pressure regulator to control the pressure of the supplied fuel. The engine also does not require a sophisticated ECU to control the operation of the fuel injector. Instead, the ECU selects together the appropriate number of pulses (as sensed by the engine load sensor 91) for a given engine load, and then the number of pulses exhaled in the engine cycle before deactivating the injector. A simple I.D. C. Can be built from chips.

  The engine of FIG. 22 can even be configured to mechanically control the injector 96 using some coupling mechanism between the throttle and the injector 96.

In all the engine embodiments described above, only a single injector is used for each working cylinder of the engine. However, the Applicant expects that each working cylinder can be provided with a plurality of injectors. This can have two advantages. First, in order to expel a given amount of fuel in each engine cycle, the number of operations of each individual injector is reduced, eliminating the need to operate each injector at such a high speed during use. This can bring practical benefits. Second, if the injector for a particular working cylinder is constructed to expel different amounts of fuel, the engine management system will “finer” the amount of fuel expelled in each work cycle. Both operations can be controlled in a controlled manner. For example, if a single injector for injecting 1 pulse per 0.1 mm ³ to the engine is provided, the total fuel a multiple of 0.1 mm ³ to be injected per engine cycle, i.e. 0.1 mm ³ , 0.2 mm ³ , 0.3 mm ³ , and up to 0.5 mm ³ . However, if the engine is provided with two injectors, one injecting 0.1 mm ³ pulses and the other injecting 0.05 mm ³ pulses, the engine will have 0.05 mm ³ , 0 in each engine cycle. The total amount of fuel that can be 1 mm ³ , 0.15 mm ³ , 0.2 mm ^3, etc. can be discharged. This is achieved with fewer injector actuations than would be required if the working cylinder had only injectors capable of 0.05 mm ³ pulses.

FIG. 1 is a schematic diagram of an internal combustion engine having a fuel injection system according to the present invention. FIG. 2 is a schematic diagram of a first type fuel injector according to the present invention suitable for use in the engine of FIG. FIG. 3 is a schematic diagram of a second type fuel injector suitable for use in the engine of FIG. FIG. 4 shows a modification of the fuel injector of FIG. FIG. 5 is a schematic diagram of a third type fuel injector suitable for use in the engine of FIG. FIG. 6 is a view showing a modification of the fuel injector of FIG. FIG. 7 is a schematic diagram of a fourth type fuel injector suitable for use in the engine of FIG. 8a, 8b, 8c and 8d are diagrams illustrating the operation of the fuel injector of FIG. FIG. 9 is a detailed view of the fuel injector of FIG. FIGS. 10a to 10d are diagrams illustrating the operation of a modified version of the fuel injection of FIGS. FIG. 11 is a view showing a one-way check valve of the fuel injector of FIGS. FIG. 12 shows a one-way check valve of the fuel injector of FIGS. 10a) to 10d). FIG. 13 is a view showing a one-way check valve that can be used in place of the check valve shown in any of the fuel injectors of FIGS. 7 to 10d. FIG. 14 is a diagram illustrating the types of signals used in prior art fuel injector systems to control the amount of fuel delivered to the combustion chamber in each engine cycle. FIG. 15 illustrates the present invention to operate the fuel injector of FIG. 1 (eg, any type of fuel injector of FIGS. 2-10d) to control the amount of fuel delivered to the combustion chamber in each operating cycle. It is a figure which shows the control signal used by 1. FIG. 16a is a diagram showing a rotation signal extracted from the engine camshaft or crankshaft of the engine of FIG. FIG. 16B is a diagram showing control signals generated for full load operation of the engine of FIG. FIG. 16c is a diagram showing control signals generated for partial load operation of the engine of FIG. FIG. 16d is a diagram showing control signals generated for engine idling of the engine of FIG. FIG. 16e is a diagram illustrating a control device signal generated during start-up of the engine of FIG. 17 is a schematic illustration of the inlet passage of the internal combustion engine of FIG. 1 equipped with a slightly modified version of the fuel injector of FIG. 18 is a cross-sectional view of the nozzle of the fuel injector of FIG. 19 is a cross-sectional view of a portion of the fuel injector of FIG. 20a-20d are schematic diagrams of the operation of the fuel injector of FIGS. 17-19. FIGS. 21a-21d illustrate alternative nozzle orifice shapes for the fuel injectors of FIGS. 17-20. FIG. 22 is a schematic view of a second embodiment of an internal combustion engine having a fuel injection system according to the present invention. FIG. 23 is a schematic illustration of a fuel injector suitable for use with the engine of FIG. FIG. 24 is a schematic diagram of the fuel injector of FIG. 23 and its arrangement with the cam surface used to drive it. FIG. 25 is a schematic diagram of a second embodiment of a fuel injector suitable for use with the engine of FIG. 18 instead of the fuel injector shown in FIG. FIG. 26 is a diagram of a modification of the cam array of FIG.

Claims (30)

A variable volume combustion chamber;
An intake system for exhaling supply air to the combustion chamber;
An exhaust system for relaying combustion gas from the combustion chamber to the atmosphere;
A fuel injection system for exhaling fuel into the air supply so as to burn together in the combustion chamber, the fuel injection system comprising:
A fuel injector that functions as a positive displacement pump and dispenses a fixed amount of fuel for each operation of the injector;
An internal combustion engine comprising: a control device for controlling the operation of the fuel injector;
In each of at least most of the engine cycle, the fuel injector is actuated multiple times by the controller,
In response to an increase in engine speed and / or load, the controller increases the amount of fuel delivered per engine cycle by increasing the number of actuations of the fuel injector per engine cycle;
In response to a decrease in engine speed and / or load, the controller reduces the amount of fuel delivered per engine cycle by reducing the number of actuations of the fuel injector per engine cycle ;
The fuel injector is
A housing in which a fuel chamber is formed;
An electric coil;
A piston that slides axially in the housing lumen by the action of the electrical coil, sliding between two end stops to ensure that the piston moves a set distance with each actuation; , Ru comprising an internal combustion engine. A variable volume combustion chamber;
An intake system for exhaling supply air to the combustion chamber;
An exhaust system for relaying combustion gas from the combustion chamber to the atmosphere;
A fuel injection system for exhaling fuel into the air supply so as to burn together in the combustion chamber, the fuel injection system comprising:
A plurality of fuel injectors, each functioning as a positive displacement pump and dispensing a fixed amount of fuel with each actuation of the injector;
At least a first fuel injector of the plurality of fuel injectors dispenses a first set amount of fuel different from a second set amount dispensed by at least the second fuel injector of the plurality of fuel injectors. To do
A control device for controlling the operation of each of the plurality of fuel injectors,
The fuel injector is actuated multiple times by the controller in each of at least a majority of the engine cycle;
In response to an increase in engine speed and / or load, the controller increases the amount of fuel delivered per engine cycle by increasing the number of actuations of the fuel injector per engine cycle; and In response to a decrease in engine speed and / or load, the controller reduces the amount of fuel delivered per engine cycle by reducing the number of actuations of the fuel injector per engine cycle ;
Each fuel injector
A housing in which a fuel chamber is formed;
An electric coil;
A piston that slides axially in the housing lumen by the action of the electrical coil, sliding between two end stops to ensure that the piston moves a set distance with each actuation; , Ru comprising an internal combustion engine.   The fuel injector uses electric power to dispense fuel therefrom, and the control device generates a pulse control signal to control the / each fuel injector, each pulse being said / each The internal combustion engine according to claim 1, wherein fuel is dispensed to a fuel injector, and the electronic control unit changes the number of fuel discharged by changing the number of pulses per engine cycle. A sensor is provided to monitor the engine load and provide a signal indicating the engine load to the electronic control unit, and the electronic control unit calculates the number of pulses to be generated in each engine cycle in consideration of the engine load. to internal combustion engine according to claim 3. The timing signal is associated with an engine crankshaft or camshaft to generate a timing signal related to rotation of the crankshaft or camshaft and to trigger a pulse generated by the electronic controller. The internal combustion engine of claim 4 used by the electronic control unit . The internal combustion engine according to claim 1 or 2 , wherein the / each fuel injector includes a biasing spring acting on the piston . The internal combustion engine of claim 6 , wherein the electrical coil surrounds the piston . The end plate is connected to the piston, and Ru extends outwardly from the piston across an end face of the electrical coil, an internal combustion engine according to claim 7. The / each fuel injector includes a fuel inlet, a fuel outlet, and a one-way inlet valve that prevents fuel from being discharged from the fuel chamber to the fuel inlet while drawing fuel from the fuel inlet into the fuel chamber; A one-way outlet valve for preventing fuel from being drawn into the fuel chamber from the fuel outlet while discharging fuel from the fuel chamber to the fuel outlet. The internal combustion engine according to one item . The internal combustion engine of claim 9, wherein the one-way inlet valve is a spring biased valve . The internal combustion engine according to claim 9 or 10, wherein the one-way outlet valve is a spring-biased valve . The one-way inlet valve is Ru provided in the fuel inlet passage of the housing, an internal combustion engine according to any one of claims 9 to 11. A fuel inlet passage through which fuel is discharged into the fuel chamber is provided in the piston, the one-way inlet valve is provided in the fuel inlet passage of the piston, and the one-way inlet valve is in close contact with the seat includes a valve member, said one-way inlet valve so moment of the valve member resulting from the movement of the piston to facilitate the opening and closing both of the one-way inlet valve is configured, any one of claims 9 to 11 An internal combustion engine according to 1. The internal combustion engine of claim 13 , wherein the valve member is a ball . The internal combustion engine of claim 13 , wherein the valve member is a disk . A piston spring biases the piston into engagement with one of the end stops, and a solenoid slides the piston against the other end stop against the biasing force applied by the piston spring. It acts to engage, claim 2 or internal combustion engine according to any one of from 6 15. The piston spring, the fuel you urging the piston so as to be discharged from the fuel chamber, an internal combustion engine according to claim 16. The internal combustion engine of claim 16 , wherein the piston spring biases the piston to draw fuel into the fuel chamber . 16. An internal combustion engine according to any one of claims 1, 2 or 6 to 15 comprising a shim that provides one of the end stops . 20. An internal combustion engine according to any one of claims 1, 2 or 6 to 19, comprising a shim attached to the piston . 21. A method of manufacturing an internal combustion engine according to claim 19 or 20 , comprising selecting shims formed to a size that achieves a selected set travel distance . Some use shims to set the piston travel distance, others do not use shims, and select different sized shims for different engines, resulting in different piston travel distances. 21. A plurality of internal combustion engines according to any one of claims 1, 2, or 6 to 20, wherein a fuel injector is provided for dispensing different set amounts of fuel by setting different travel distances to the piston. Engine manufacturing method . An inlet passage through which air is discharged into the combustion chamber of the engine, a venturi provided in the inlet passage, a throttle valve in the inlet passage, and a bypass passage for discharging air downstream of the throttle valve in the inlet passage. has the / each fuel injector is discharged fuel into the mixing chamber, where fuel is taken up by air from the bypass passage, Ru is discharged into the throat of the venturi mixing fuel and air and then through the nozzle An internal combustion engine according to any one of claims 1 to 20 . 24. The internal combustion engine of claim 23 , wherein the air bypass passage is connected to the atmosphere . An inlet passage through which air is expelled into the combustion chamber of the engine, a venturi provided in the inlet passage, a throttle valve in the inlet passage, and exhaust gas or a mixture of air and exhaust gas is supplied to the throttle valve in the inlet passage. A bypass passage that evacuates downstream, wherein each of the fuel injectors expels fuel into the mixing chamber, where the fuel is taken up by gas from the bypass passage, and the mixed fuel and gas then passes through the nozzle to the 23. The internal combustion engine according to any one of claims 1 to 22 , which is discharged into a venturi throat . Wherein the nozzle is a sonic nozzle, the internal combustion engine according to any one of claims 23 to 25. Wherein the nozzle is atomizing nozzle having a non-circular orifices, the internal combustion engine according to any one of claims 23 to 26. The nozzle Ru Ah in atomizing nozzle having an array of orifices, internal combustion engine according to any one of claims 23 to 26. Expelling multiple fuel pulses into the combustion chamber at each engine cycle using the / each fuel injector ; and
In response to changes in engine speed and / or load by changing the number of fuel pulses per engine cycle, thereby controlling the amount of fuel delivered to the combustion chamber in each cycle, including, it claims 1 20 29. A method of operating an internal combustion engine according to any one of claims 23-28. The number of fuel pulses per engine cycle is maintained at a first high level in the period immediately following engine startup, and then reduced to a low level in subsequent engine cycles until the next engine start. Item 30. The method according to Item 29 .

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