JP2008202557A - Engine controlling method and controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a decompression valve from freezing and stopping movement when it is cold, and to facilitate restarting of an engine when it is cold, in the engine equipped with the decompression valve. <P>SOLUTION: The engine controlling device controls at least the decompression valve and a fuel injection device of the engine 1 comprising: a decompression hole communicating the inside of a cylinder to the outside; the decompression valve 116 opening/closing the decompression hole; and the fuel injection device INJ. The engine controlling device is provided with: an engine stopping time fuel injection controlling means 61 controlling the fuel injection device to carry out fuel cut for stopping the supply of fuel to the engine when stopping the engine; and an engine stopping time decompression valve controlling means 62 controlling the decompression valve to open when the stopping the engine. When the engine is stopped, compressed air which does not include fuel is made to flow through the decompression hole, thereby carrying out air blow of the decompression valve. Moisture adhering to the decompression valve is removed thereby. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control that controls at least a decompression valve and a fuel injection device of an engine including a decompression hole that allows each cylinder to communicate with the outside, a controllable decompression valve that opens and closes the decompression hole, and a fuel injection device. It is about the method.

  In the engine starter disclosed in Patent Document 1, a decompression mechanism having a structure for forcibly lifting an exhaust valve by exciting a solenoid is provided, and the exhaust valve is opened by the decompression mechanism (compression of the engine). Cranking is performed (with reduced torque), and when the rotational speed of the crankshaft is increased to a predetermined rotational speed in the running section, the exhaust valve is closed and the compression stroke is performed.

However, a decompression mechanism having a structure in which the exhaust valve is lifted up and forcedly opened is not preferable because it has a complicated structure and increases the cost of the engine. In view of this, the present applicant has disclosed in Japanese Patent Application No. 2006-56344 a cylinder head having a decompression hole that communicates the inside of each cylinder of the engine to the outside (cam chamber, intake pipe, exhaust pipe, blow-by gas circulation passage, air cleaner, etc.). By providing a controllable decompression valve (solenoid valve) that opens and closes this decompression hole, opening the decompression valve when cranking when starting the engine, and closing the decompression valve after starting the engine, It was proposed to facilitate cranking and start the engine.
JP 2002-332938 A

  When a decompression hole and a decompression valve that opens and closes the decompression hole are provided in the cylinder head of the engine, cranking of the engine can be performed without complicating the engine structure as in the case of forcibly lifting up the exhaust valve. The engine startability can be improved easily. However, when such a decompression mechanism is used, when the engine is used at temperatures below freezing, moisture contained in the combustion gas may condense on the decompression valve. If the engine is stopped, water that has condensed and adhered to the decompression valve will freeze, causing the problem that the decompression valve will not move the next time the engine is started. If the decompression valve is not opened when the engine is started at a low temperature, the load applied to the starter motor in the compression stroke of the engine increases and the cranking speed decreases, so the engine startability deteriorates.

  An object of the present invention is to provide an engine control method capable of facilitating the start of an engine by preventing a situation in which moisture that adheres to a decompression valve freezes and the decompression valve does not move in a cold region. An object of the present invention is to provide an engine control device used for carrying out this control method.

  The present invention relates to an engine control that controls at least a decompression valve and a fuel injection device of an engine including a decompression hole that allows each cylinder to communicate with the outside, a controllable decompression valve that opens and closes the decompression hole, and a fuel injection device. In the present invention, when the engine is stopped, the fuel injection device and the decompression valve are controlled so that the fuel cut is performed to stop the supply of fuel to the engine and the decompression valve is opened. Control at stop.

The moisture adhering to the decompression valve is a condensation of moisture contained in the combustion gas. The water contained in the combustion gas is hydrogen (H) contained in fuel gasoline that is burned and combined with oxygen in the air to form water (H ₂ O). As described above, when the decompression valve is opened with the fuel cut when the engine is stopped, the dry compressed air containing no fuel flows to the outside through the decompression hole and decompression valve. Thus, the water adhering to the decompression valve can be scattered. Therefore, the decompression valve can be prevented from freezing when the stopped engine is left at a temperature below freezing, and the decompression valve can be prevented from moving at the next engine start.

  As described above, when the engine stop control is performed, it is preferable to control the intake air amount adjusting means so as to increase the intake air amount of the engine at the same time. In an engine to be controlled, an electronically controlled throttle configured to be driven by an actuator and electronically controlled so that the opening degree coincides with the target opening degree is used as the intake air amount adjusting means. In this case, when the fuel is cut when the engine is stopped, the control of increasing the intake air amount can be performed by controlling the electronic control throttle so as to increase the throttle valve opening.

  In addition, when an idle control valve [ISC valve (Idle Speed Control Valve)] is provided so as to bypass the throttle valve in order to control the idling rotational speed, the fuel is cut when the engine is stopped. By controlling to increase the opening degree of the idle control valve, it is possible to perform control to increase the intake air amount.

  If a fuel cut is performed to stop the engine in an idling state where the throttle is closed, the engine stops at a few revolutions. If the time for flowing air through the decompression hole is short, the moisture adhering to the decompression valve may not be sufficiently scattered. On the other hand, when the control is performed when the engine is stopped, if the control is performed to increase the intake air amount of the engine at the same time, the throttle loss (compression loss) is reduced, so that the engine can be coasted longer. It is possible to increase the effect of scattering the water adhering to the decompression valve by lengthening the time for air to flow through the decompression hole.

  In the present invention, when the engine stop control is performed, an air blower for driving a starter motor provided for starting the engine for a set time to maintain a state in which air flows through the decompression hole. -Cranking is preferred.

  In this way, if air blow / cranking is performed during engine stop control, the time for air to flow through the decompression hole (air blow) can be lengthened, so the moisture adhering to the decompression valve Removal can be ensured.

  In the present invention, when performing engine stop control, an air blow cranking for driving a starter motor provided to start the engine and maintaining a state where air flows through the decompression hole, It may be performed until the number of rotations of the crankshaft of the engine reaches a set value.

  In an engine, fuel may be cut when the engine is decelerated during operation of the engine. As described above, when the fuel cut is performed even when the engine is decelerated, it is preferable to perform control for opening the decompression valve also when the fuel is cut when the engine is decelerated.

  As described above, when the control is performed to open the decompression valve even when the fuel cut is performed during the operation of the engine, the opportunity for drying the decompression valve can be increased, so that the decompression of the decompression valve can be prevented more reliably. be able to.

  When starting the engine, rotate the crankshaft of the engine once in the reverse direction with the decompression valve open, and the crank angle range suitable for injecting fuel in preparation for the first ignition at the start It is preferable to perform start-up control in which the initial fuel injection at the start is performed at the position, and then the crankshaft is rotated in the forward direction to perform ignition at a crank angle position suitable as an ignition position at the start.

  As described above, when the crankshaft is rotated once in the reverse direction at the start and the first fuel injection at the start is performed and then the crankshaft is rotated in the forward direction, the cylinder that is initially ignited at the start Since the air-fuel mixture can be reliably supplied, the initial explosion can be surely performed in the cylinder that first reaches the ignition timing at the time of starting, and the startability of the engine can be improved.

  The present invention also provides an engine control for controlling at least a decompression valve and a fuel injection device of an engine including a decompression hole that allows the inside of the cylinder to communicate with the outside, a controllable decompression valve that opens and closes the decompression hole, and a fuel injection device. Applied to the device.

  In the present invention, when the engine is stopped, the fuel injection control means for controlling the fuel injection device so as to perform the fuel cut for stopping the supply of fuel to the engine, and the decompression unit when the engine is stopped. And a decompression valve control means for stopping the engine so as to open the valve.

  In a preferred aspect of the present invention, an engine stop intake air amount control means is further provided for controlling the intake air amount adjusting means so as to simultaneously increase the intake air amount of the engine when the engine stop control is performed.

  According to still another preferred aspect of the present invention, when the engine stop control is performed, a starter motor provided for starting the engine is driven for a set time to maintain a state in which air flows through the decompression hole. An engine stop starter motor control means for controlling the starter motor so as to perform air blow / cranking is further provided.

  According to still another preferred aspect of the present invention, an air blower for driving a starter motor provided to start the engine and maintaining a state where air flows through the decompression hole when the engine is stopped is controlled. -An engine stop starter motor control means for performing cranking until the number of rotations of the crankshaft of the engine reaches a set value is further provided.

  According to still another preferred aspect of the present invention, a fuel injection control means at the time of deceleration for controlling the fuel injection device so as to perform a fuel cut when the engine is decelerated during operation of the engine, and a fuel cut at the time of engine deceleration And a decompression decompression valve control means for controlling to open the decompression valve at the time of the engine.

  According to still another preferred aspect of the present invention, when the engine is started, the decompression valve is opened, and when the engine is completely started, the decompression valve control means for starting is controlled. The starter reverse rotation drive means that rotates the crankshaft of the engine once in the reverse direction and the initial fuel injection at the crank angle range suitable for injecting fuel in preparation for the initial ignition at the start Starting fuel injection control means for controlling the fuel injection device to perform, starter forward rotation driving means for rotating the crankshaft in the forward direction after the starter motor drive by the starter reverse rotation driving means, and ignition position at the start And a starting point fire control means for causing the ignition device for igniting the engine at a crank angle position suitable for .

  The decompression hole can be provided so that each cylinder of the engine communicates with a cam chamber in which cams for driving intake valves and exhaust valves are arranged.

  The decompression hole may be provided so as to allow communication between each cylinder of the engine and the exhaust port.

  According to the present invention, when the engine is stopped, the decompression valve is opened in a state where the fuel is cut. Therefore, the dry compressed air not containing the fuel is allowed to flow to the outside through the decompression hole and the decompression valve. Moisture adhering to the bulb can be scattered. Therefore, the decompression valve can be prevented from freezing when the stopped engine is left at a temperature below the freezing point, and the decompression valve can be prevented from moving at the next engine start.

  Further, in the present invention, when the engine stop control is performed, if the intake air amount adjusting means is controlled so as to increase the intake air amount of the engine at the same time, the throttle loss (compression loss) is reduced. Since the engine can be inertially rotated for a longer time, the time for air to flow through the decompression hole can be lengthened, and the effect of scattering the moisture adhering to the decompression valve can be enhanced.

  In the present invention, when performing engine stop control, an air blow clutch for driving a starter motor provided for starting the engine for a set time to maintain a state in which air flows through the decompression hole. When ranking is performed, the time for air to flow through the decompression hole can be lengthened, so that it is possible to ensure the removal of moisture adhering to the decompression valve.

  In the present invention, when the control is performed to open the decompression valve even when the fuel cut is performed during operation of the engine, the opportunity for drying the decompression valve can be increased, so that the decompression valve can be further frozen. It can be surely prevented.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows the configuration of an engine system provided with an engine control apparatus according to the present invention. In the figure, ENG is a parallel 2-cylinder 4-cycle engine, and the phase difference between the combustion cycle of the first cylinder and the combustion cycle of the second cylinder of this engine is 360 °. Reference numeral 1 denotes an engine main body. The engine main body 1 includes two cylinders 101 (only the first cylinder is shown in the drawing) in which a piston 100 is provided, and a piston 100 in the cylinder via a connecting rod 102. And a connected crankshaft 103.

  As shown in FIG. 4, the engine body 1 has an intake port 104 and an exhaust port 105, and an intake pipe 106 is connected to the intake port 104. A throttle valve 107 is provided in the intake pipe 106. An intake valve 108 and an exhaust valve 109 are provided so as to open and close the intake port 104 and the exhaust port 105, respectively. A cam cover 111 is attached to an upper portion of the cylinder head 110 of the engine body, and a cam chamber 113 that houses a cam mechanism 112 that drives the intake valve 108 and the exhaust valve 109 is provided inside the cam cover 111.

  In the present embodiment, a decompression hole 115 (see FIG. 4) is provided so that each cylinder 101 and the cam chamber 113 communicate with each other. In addition, a decompression valve 116 comprising an electromagnetic valve that can be controlled to open and close the decompression hole 115 is provided. The decompression valve 116 is opened when the engine is started, and the decompression valve 116 is controlled so that the decompression valve 116 is closed after the engine is started. Valve control means is provided.

  The engine ENG also has a fuel injection device that injects fuel to generate an air-fuel mixture supplied into the cylinder 101 through the intake pipe 106, an ignition device that ignites the air-fuel mixture compressed in the cylinder 101, and a crankshaft 103. And a starter motor that can be rotated in the forward direction and the reverse direction.

  In the illustrated example, an injector (electromagnetic fuel injection valve) 2 is attached so as to inject fuel into an intake pipe or an intake port downstream of the throttle valve 107. The injector 2 is a well-known one having an injector body having an injection hole at the tip, a needle valve that opens and closes the injection hole, and a solenoid that drives the needle valve. The injector body includes a fuel in the fuel tank 3. Fuel is supplied from a fuel pump 5 that pumps out 4. The pressure of the fuel supplied from the fuel pump 5 to the injector 2 is kept constant by the pressure regulator 6. The solenoid of the injector 2 is connected to an injector drive circuit provided in an electronic control unit (ECU) 10. The injector drive circuit gives a drive voltage to the solenoid of the injector 2 when an injection command signal is generated in the ECU. The injector 2 opens the valve and injects fuel into the intake pipe while the drive voltage Vinj is applied to the solenoid from the injector drive circuit. When the pressure of the fuel applied to the injector is kept constant, the fuel injection amount is managed by the injection time (time during which the injector valve is opened).

  In this example, a fuel injection device is constituted by an injector 2, an injector drive circuit described later, and fuel injection control means for giving an injection command to the injector drive circuit.

  As shown in FIG. 1, the cylinder head of the engine body is also provided with a spark plug 12 for each cylinder with the discharge gap at the tip facing the combustion chamber in each cylinder 101. The ignition plug is connected to the secondary side of the ignition coil 13 for each cylinder. The primary side of the ignition coil 13 for each cylinder is connected to an ignition circuit (not shown) provided in the ECU 10. The ignition circuit is a circuit that induces a rapid change in the primary current I1 of the ignition coil 13 when an ignition command is given from the ignition command generator, and induces a high voltage for ignition on the secondary side of the ignition coil 13. The ignition plug 12, the ignition coil 13, an ignition circuit (not shown), and an ignition command generator for giving an ignition command to the ignition circuit constitute an ignition device that ignites the engine. The ignition command generation unit calculates an ignition position at the time of steady operation of the engine, and a steady-time fire control means for generating an ignition command when the calculated ignition position is detected, and starts the engine when the engine is started And a starting point fire control means for generating an ignition command at a suitable ignition position.

  The engine shown in FIG. 1 is provided with an ISC (Idle Speed Control) valve 120 operated by a solenoid so as to bypass the throttle valve. An ECU 10 is provided with an ISC valve drive circuit for supplying a drive signal Visc to the ISC valve 120. The drive signal Visc is applied to the ISC valve 120 so as to keep the idling rotational speed of the engine constant.

  In the present embodiment, a rotating electrical machine (called a starter generator) SG that is driven as a brushless motor when the engine is started and is operated as a generator (generator) after the engine is started is attached to the engine. Is used as a starter motor. The rotating electrical machine SG includes a rotor 21 attached to an engine crankshaft 103 and a stator 22 fixed to a case of the engine body.

  The rotor 21 includes an iron rotor yoke 23 formed in a cup shape and a permanent magnet 24 attached to the inner periphery thereof. In this example, the rotor 21 is attached to the inner periphery of the rotor yoke 23. The permanent magnet 24 constitutes a 12-pole magnet field. The rotor 21 is a screw member in which a tapered portion at the tip of the crankshaft 103 of the engine is fitted into a tapered hole formed inside a boss portion 25 provided in the center of the bottom wall portion of the rotor yoke 23. Thus, the boss portion 25 is fastened to the crankshaft 103 by being fastened to the crankshaft 103.

  The stator 22 is wound around a stator core 26 having a structure in which 18 salient pole portions 26p are radially projected from the outer periphery of an annular yoke 26y, and a series of salient pole portions 26p of the stator core. The armature coils 27 are connected in phase, and the magnetic pole portions at the tips of the salient pole portions 26p of the stator core 26 are opposed to the magnetic pole portions of the rotor via a predetermined gap.

  The rotor yoke 23 is formed with a reluctator r formed of arcuate protrusions. Pulses having different polarities are detected on the engine case side by detecting the front end edge and the rear end edge in the rotation direction of the reluctator r. A signal generator 28 is attached. Further, on the stator side of the rotating electrical machine SG, holes are arranged at detection positions set for the respective armature coils of the three phases, and detect the polarity of each magnetic pole of the magnet field of the rotor 21. Hall sensors 29u to 29w such as ICs are provided. In FIG. 1, the three-phase hall sensors 29 u to 29 w are illustrated as being disposed outside the rotor yoke 23, but in reality, the three-phase hall sensors 29 u to 29 w are arranged on the rotor 21. The printed circuit board is disposed on the inner side and fixed to the stator 22. The hall sensor is provided in the same manner as that in a normal three-phase brushless motor. The hall sensors 29u to 29w output position detection signals hu to hw composed of voltage signals having different levels depending on whether the detected magnetic pole is the N pole or the S pole.

  The three-phase armature coil of the rotating electrical machine SG is connected to the AC side terminal of the motor drive / rectifier circuit 31 through wirings 30u to 30w, and the battery 32 is connected between the DC side terminals of the motor drive / rectifier circuit 31. The motor drive / rectifier circuit 31 is a bridge-type three-phase inverter circuit (motor drive circuit) in which each side of a three-phase H-bridge is configured by switch elements Qu to Qw and Qx to Qz that can be turned on / off such as MOSFETs and power transistors. And a diode bridge three-phase full-wave rectifier circuit composed of diodes Du to Dw and Dx to Dz connected in reverse parallel to the switching elements Qu to Qw and Qx to Qz of the inverter circuit, respectively. It is.

  When the rotating electrical machine SG is operated as a brushless motor (starter motor), the switching element of the inverter circuit is controlled to be turned on / off according to the rotational angle position of the rotor 21 detected from the outputs of the hall sensors 29u to 29w. A driving current commutated in a predetermined phase sequence is supplied from the battery 32 to the three-phase armature coil 27 through the inverter circuit.

  When the rotary electric machine SG is operated as a generator after the engine is started, the three-phase AC output obtained from the armature coil 27 is supplied to the battery 32 and the battery through the full-wave rectifier circuit in the motor drive / rectifier circuit 31. Supplied to various loads (not shown) connected to both ends of 32. At this time, according to the voltage at both ends of the battery 32, the switch element constituting the upper side of the bridge of the inverter circuit or the switch element constituting the lower side of the bridge is simultaneously turned on / off, whereby the voltage at both ends of the battery 32 is set to the set value. It is controlled not to exceed.

  For example, when the voltage across the battery 32 is equal to or lower than a set value, the switch elements Qu to Qw and Qx to Qz constituting the H bridge of the inverter circuit are held in an off state, and the output of the rectifier circuit in the motor drive / rectifier circuit 31 Is applied to the battery 32 as it is. When the voltage across the battery 32 exceeds the set value, the three switch elements Qx to Qz that respectively constitute the three lower sides (or the upper side) of the bridge of the inverter circuit are turned on simultaneously, The three-phase AC output of the generator is short-circuited, and the voltage across the battery 32 is lowered below the set value. By repeating these operations, the voltage across the battery 32 is maintained at a value near the set value.

  Further, instead of performing the control as described above, the induced voltage of the armature coil is equal to the induced voltage of the armature coil from the battery 32 to the armature coil of the rotating electric machine SG, and the induced voltage of the armature coil when no load is applied. A means for controlling the inverter circuit so as to apply an AC control voltage having a predetermined phase angle is provided, and the phase of the AC control voltage applied to the armature coil from the battery side according to a change in the voltage across the battery is determined. By changing the voltage with respect to the no-load organic voltage of the armature coil, it is possible to increase or decrease the power generation output of the rotating electric machine and control the voltage across the battery 32 to be within a set range.

  When a MOSFET is used as a switching element constituting each side of the bridge of the inverter circuit, a parasitic diode formed between the drain and source of the MOSFET can be used as the diodes Du to Dw and Dx to Dz.

  In the illustrated example, in order to give engine information to the microprocessor of the ECU 10, a throttle position sensor 35 that detects the position (opening degree) of the throttle valve 107 and the pressure in the intake pipe downstream from the throttle valve 107 are detected. There are provided a pressure sensor 36, a coolant temperature sensor 37 for detecting the coolant temperature of the engine, and an intake air temperature sensor 38 for detecting the temperature of the air taken into the engine.

  As described above, in this embodiment, the rotor of the rotating electrical machine (starter generator) SG is directly connected to the crankshaft of the engine, and this rotating electrical machine is used as a starter motor when starting the engine. An electric machine is used as a generator. However, in the description of the engine starter described below, since the control is performed when the rotary electric machine SG is operated as a starter motor, the rotary electric machine SG is referred to as a starter motor for convenience. .

  Referring to FIG. 2, the electrical configuration of the system shown in FIG. 1 is shown in a block diagram. The ECU 10 is supplied from a microprocessor (MPU) 40, an ignition circuit 41, an injector drive circuit 42, an ISC valve drive circuit 43, a temperature sensor 44 for detecting the temperature of the motor drive / rectifier circuit 31, and the microprocessor 40. The control circuit 45 for supplying a drive signal to the switch element of the inverter circuit of the motor drive / rectifier circuit 31 according to the command, the decompression valve drive circuit 46 for supplying the drive current to the decompression valve 116, and a predetermined number of interface circuits I / F And.

  The microprocessor 40 constitutes various control means necessary for controlling the engine by executing a predetermined program stored in the ROM. In the illustrated example, in order to give engine information to the microprocessor, the throttle position signal Sa obtained from the throttle position sensor 35, the intake pipe pressure detection signal Sb obtained from the pressure sensor 36, and the cooling obtained from the cooling water temperature sensor 37 are shown. The water temperature detection signal Sc and the intake air temperature detection signal Sd obtained from the intake air temperature sensor 38 are input to the microprocessor in the ECU 10 through the interface circuit I / F. The output signals hu to hw of the hall sensors 29u to 29w and the output Sp of the signal generator 28 are inputted to the microprocessor 40 through a predetermined interface circuit I / F.

  A primary current I1 is supplied from the ignition circuit 41 in the ECU 10 to the ignition coil 13, and a drive voltage Vinj is supplied from the injector drive circuit 42 in the ECU 10 to the injector 2. Further, drive signals (signals for turning on the switch elements) Su to Sw and Sx to Sz are supplied from the control circuit 45 to the six switch elements Qu to Qw and Qx to Qz of the inverter circuit of the motor drive / rectifier circuit 31, respectively. Is given.

  2, 47 is a power supply circuit to which the output voltage of the battery 32 is inputted. The power supply circuit 47 outputs the power supply voltage supplied to each part of the ECU 10 by stepping down and stabilizing the output voltage of the battery 32. To do.

  In the present embodiment, the configuration of the main part of the control device including various control means configured by the microprocessor 40 is shown in FIG. In FIG. 3, INJ is a fuel injection device composed of an injector 2 and an injector drive circuit 42, and IG is an ignition device composed of an ignition coil 13 and an ignition circuit 41. AC is an intake air amount adjusting means, which is constituted by, for example, a throttle valve 107 and an ISC valve 120.

  In FIG. 3, 50 is a start command generating means for generating a start command for instructing to start the engine, 51 is a stop command generating means for generating an engine stop command, and 52 is a deceleration detection means for detecting deceleration of the engine. It is. Reference numeral 61 denotes an engine stop-time fuel injection control means for controlling the fuel injection device so as to perform a fuel cut to stop the supply of fuel to the engine when the engine is stopped. This is a decompression valve control means for controlling the opening of the decompression valve 116 when the engine is stopped.

  In the present invention, the engine stop fuel injection control means 61 and the engine stop decompression valve control means 62 are provided to supply fuel to the engine when a stop command for stopping the engine is generated. The engine is stopped when the engine is stopped, and the fuel injection device INJ and the decompression valve 116 are controlled so that the decompression valve 116 is opened.

  As described above, when the engine stop control is performed, dry air that does not contain fuel can flow through the decompression hole 115 and the decompression valve 116, and the decompression valve 116 can be blown, so that it adheres to the decompression valve 116. Moisture can be scattered and removed. Therefore, it is possible to prevent the decompression valve from freezing when the stopped engine is left at a temperature below freezing point, and prevents the decompression valve 116 from moving when the engine is started. Starting can be facilitated.

  As described above, in the present invention, the engine stop time fuel injection control means 61 and the engine stop time decompression valve control means 62 are basically provided to perform the engine stop time control. An engine stop intake air amount control means 63, an engine stop starter control means 64, a deceleration fuel injection control means 65, a deceleration decompression valve control means 66, a startup decompression valve control means 67, and a starter reverse rotation The drive means 68, the start time fuel injection control means 69, the starter normal rotation drive means 70, the start time fire control means 71, and the steady time fuel injection / ignition control means 72 are provided.

  More specifically, the intake air amount control means 63 when the engine is stopped is means for controlling the intake air amount adjusting means so as to increase the intake air amount of the engine at the same time when the engine stop control is performed. The control for increasing the intake air amount of the engine is performed by controlling the electronic control throttle so as to increase the opening degree of the throttle valve 107 or controlling the opening degree of the idle control valve 120 to be increased. be able to.

  When the engine stop intake air amount control means 63 is provided and the engine stop control is performed simultaneously with the control for increasing the intake air amount of the engine, the throttle loss (compression loss) is reduced to reduce the engine loss. Can be rotated for a longer period of time, so that the time for air to flow through the decompression hole can be lengthened to enhance the effect of scattering the moisture adhering to the decompression valve.

  The engine stop starter control means 64 drives a starter motor provided for starting the engine for a set time during engine stop control so as to maintain a state in which air flows through the decompression hole. Is a means for controlling the starter motor so as to perform air blow and cranking. By providing the starter control means 64 when the engine is stopped and performing the air blow / cranking when performing the engine stop control as described above, the time for air to flow through the decompression hole (air blow) is lengthened. Therefore, it is possible to ensure the removal of water adhering to the decompression valve.

  The deceleration fuel injection control means 65 is a means for controlling the fuel injection device to perform fuel cut when the deceleration detection means 52 detects that the engine has been decelerated during operation of the engine. The hour decompression valve control means 66 is a means for controlling the decompression valve to open when the fuel is cut when the engine is decelerated. In this way, if the decompression valve is controlled to open even when a fuel cut is performed while the engine is running, the opportunity to air blow the decompression valve can be increased, so that moisture removal from the decompression valve is ensured. Thus, the decompression valve can be more reliably prevented from freezing.

  The starting decompression valve control means 67 is a means for controlling the opening of the decompression valve when starting the engine and closing the decompression valve when the starting of the engine is completed. In this way, if a means for opening the decompression valve at the time of starting is provided, the load applied to the starter motor from the cylinder in the compression stroke during cranking is reduced, so that cranking is facilitated and engine startability is improved. Can be improved.

  The starter reverse drive means 68 is a means for once rotating the crankshaft of the engine in the reverse direction when the engine is started, and the start time fuel injection control means 69 is for injecting fuel in preparation for the first ignition at the start. It is means for controlling the fuel injection device so that the initial fuel injection at the start is performed at a crank angle position in a suitable crank angle range.

  As described above, the starter reverse rotation drive means 68 and the start time fuel injection control means 69 are provided, and the crankshaft is rotated once in the reverse direction at the start to perform the first fuel injection at the start, and then the crankshaft is turned on. By rotating in the forward direction, the air-fuel mixture can be reliably supplied to the cylinder that is initially ignited at the time of start-up. Therefore, the first explosion is surely performed in the cylinder that first reaches the ignition timing at the time of start-up. The startability of the engine can be improved.

  In particular, in the engine targeted by the present invention, since a decompression hole that communicates the inside of each cylinder to the outside is provided in the cylinder head of the engine, in the process in which the piston is displaced toward the top dead center of the compression stroke, Since a part of the air-fuel mixture in the cylinder flows out through the decompression hole, the compression torque can be reduced, and the piston can exceed the maximum compression torque position in a short time, without using a large starter motor. However, it is possible to improve the startability of the engine by completing the compression stroke performed first after the start of the engine in a short time.

  The decompression hole may be provided so that the inside of the cylinder (combustion chamber) communicates with the exhaust port, and communicates with a portion other than the exhaust port, for example, a cam chamber in which a cam for driving the intake / exhaust valve is accommodated. May be.

  When the decompression hole is communicated with the exhaust port, unburned gas blows through the decompression hole to the exhaust port, which may deteriorate the exhaust gas component. In contrast, when the decompression hole is communicated with the cam chamber, it is possible to prevent the unburned gas from being discharged. In the cam chamber where the blow-by gas (unburned gas leaked from the cylinder) originally accumulates, the blow-by gas reduction passage connected to the crank chamber or the blow-by gas reduction directly connected to the cam chamber Uncombusted gas that has been connected to the intake system through the passage and leaked from the cylinder into the cam chamber is returned to the intake system, so if the decompression hole was provided to communicate with the cam chamber, it leaked through the decompression hole. Unburned gas can be returned to the cylinder and burned again through the intake system.

  In FIG. 3, a starter forward rotation drive means 70 is a means for rotating the crankshaft in the forward direction after the starter motor drive by the starter reverse rotation drive means 68 is completed. It is means for causing an ignition device that ignites the engine at a crank angle position suitable as an ignition position to perform an ignition operation.

  The starter forward rotation driving means 70 starts the engine even when the crankshaft is stopped before the piston in a specific cylinder reaches the top dead center of the compression stroke in the process of rotating the crankshaft in the forward direction. It is preferable that the starter motor be continuously driven in the forward rotation direction until the above is confirmed.

  When using a starter motor whose output torque is smaller than the maximum load torque (compression torque) applied to the crankshaft during the engine compression stroke, if the engine temperature is low and the engine friction torque is large, In the process in which the piston rises toward top dead center, the motor stops when the sum of the compression torque and the friction torque exceeds the output torque of the motor. However, in the engine targeted by the present invention, the compression torque and the friction torque cannot be overcome because compression leakage occurs through the decompression hole in the process in which the piston rises toward the top dead center of the compression stroke. If the starter motor continues to be driven even after the starter motor stops, the piston rises as the compression torque gradually decreases due to compression leakage, and the crankshaft rotates at a very low speed. When the piston exceeds the maximum compression torque position before the top dead center of the compression stroke (usually, a position near 30 ° before the top dead center of the compression stroke), the load applied to the starter motor becomes lighter, so the crankshaft As the piston starts to rotate, the piston easily exceeds the top dead center of the compression stroke, and the compression stroke is completed.

  In FIG. 3, a steady-state fuel injection / ignition control means 72 is a means for controlling the fuel injection amount after the start of the engine is completed and for controlling the ignition position. It is calculated when a predetermined fuel injection timing is detected by calculating the fuel injection time (injection time) for the control conditions such as water temperature, intake pipe pressure, atmospheric pressure, throttle valve opening, etc. A fuel injection control means for supplying an injector drive pulse having a pulse width necessary for injecting fuel from the injector during the injection time to the injector drive circuit 42, and calculating an engine ignition position with respect to the engine speed. And an ignition control means for giving an ignition signal to the ignition circuit 41 when the calculated ignition position is detected.

  FIG. 3 is a flowchart showing an algorithm of tasks to be executed by the microprocessor in order to constitute the decompression valve control means 62, the deceleration decompression valve control means 66, and the startup decompression valve control means 67 shown in FIG. This is shown in FIG. The task in FIG. 5 is executed at a minute time interval. When this task is started, it is determined in step S1 whether or not the operation mode is the start mode. As a result, when the operation mode is the start mode, the process proceeds to step S2 and the decompression valve 116 is opened, and then this task is terminated. When it is determined in step S1 that the operation mode is not the start mode, the process proceeds to step S3 to determine whether or not the fuel cut at the time of deceleration is performed. In step S4, the decompression valve 116 is opened.

  When it is determined in step S3 that the fuel cut during deceleration is not performed, the process proceeds to step S5 to determine whether or not the fuel cut is performed when the engine is stopped. As a result, when it is determined that the fuel is cut when the engine is stopped, the routine proceeds to step S6, where the decompression valve 116 is opened and this task is terminated. If it is determined in step S5 that the fuel is not cut when the engine is stopped, the process proceeds to step S7 to close the decompression valve 116, and then this task is terminated.

  In the case of the algorithm shown in FIG. 5, the decompression-time decompression valve control means 67 is constituted by steps S1 and S2, and the deceleration-time decompression valve control means 66 is constituted by steps S3 and S4. Further, the decompression valve control means 62 at the time of engine stop is constituted by steps S5 and S6.

  Next, with reference to FIG. 6, a description will be given of tasks executed by the microprocessor in order to constitute the engine stop intake air amount control means 63 shown in FIG. The task shown in FIG. 6 is also repeatedly executed at a minute time interval. When the task of FIG. 6 is started, it is first determined in step S11 whether or not the operation mode is the start mode. If it is determined that the operation mode is the start mode, the process proceeds to step S12 and the fuel cut when the engine is stopped is performed. Determine whether it is done. As a result, when it is determined that the fuel cut is performed when the engine is stopped, the process proceeds to step S13, where the target opening of the ISC valve 120 is set to fully open, and this task ends. When it is determined at step S11 that the operation mode is not the start mode and when it is determined at step S12 that the fuel cut is not performed when the engine is stopped, the routine proceeds to step S14, where the target opening of the ISC valve is set at the time of steady operation. Set the opening to the end of this task.

  FIG. 7 shows an algorithm of a task that is repeatedly executed by the microprocessor at a minute time interval in order to constitute the engine stop starter control means 64 that controls the starter motor so as to perform air blow cranking when the engine is stopped. is there. When the task of FIG. 7 is started, it is determined in step S21 whether or not the operation mode is the complete explosion mode (mode during steady operation). If the operation mode is the complete explosion mode, the engine is stopped in step S22. Determine if there is a request. As a result, when it is determined that there is a request to stop the engine, the process proceeds to step S23 to determine whether or not the time during which air blow / cranking is performed is within a set time. When it is determined in step S23 that the time during which air blow / cranking is performed is within the set time, the process proceeds to step S24 to issue a request to drive the starter motor SG, and in step S25, air blow / cranking is performed. Count up the air blow / cranking timer that counts the current time and finish this task.

  If it is determined in step S22 that there is no engine stop request, and if it is determined in step S23 that the air blow / cranking time has exceeded the set time, the process proceeds to step S26 and the starter motor SG is turned on. Stop and end this task.

  If it is determined in step S21 that the operation mode is not the complete explosion mode, the process proceeds to step S27 to stop the starter motor SG, and after resetting the air blow / cranking timer in step S28, this task is terminated.

  In the above-described embodiment, when the engine stop control is performed, the starter motor control means at the time of engine stop is configured to drive the starter motor for a set time and perform air blow / cranking. When the engine stop control is performed, the starter motor is driven until the number of rotations of the crankshaft of the engine reaches a set value (for example, 6) [while the crankshaft rotates for a set number of times (for example, 6)) Thus, the starter motor control means at the time of engine stop can be configured to perform air blow / cranking.

  In the above example, an engine having a starter motor is taken as an example, but the present invention can also be applied to an engine that is started by a starting device that is operated by human power such as a recoil starter.

  In the above example, when the engine is started, the crankshaft is once rotated in the reverse direction and then rotated in the forward direction. However, the present invention is also applied to the case where the crankshaft is driven in the forward direction from the start. Can be applied.

It is the block diagram which showed the structure of the hardware of the engine system to which the control apparatus concerning this invention is applied. FIG. 2 is a block diagram showing an electrical configuration of the system shown in FIG. 1. It is the block diagram which showed the structure of the engine control apparatus concerning this invention. It is sectional drawing which showed the principal part of the engine shown by FIG. It is a flowchart which shows an example of the algorithm of the task which a microprocessor performs in order to comprise a decompression valve control means at the time of engine stop, a decompression decompression valve control means, and a startup decompression valve control means. It is the flowchart which showed an example of the algorithm of the task which a microprocessor performs in order to comprise an intake air amount control means at the time of an engine stop. It is the flowchart which showed an example of the algorithm of the task which a microprocessor performs in order to comprise a starter control means at the time of an engine stop.

Explanation of symbols

1 Engine body 100 Piston 101 Cylinder ENG Engine SG Rotating electric machine (starter motor)
2 Injector 10 ECU
DESCRIPTION OF SYMBOLS 12 Spark plug 13 Ignition coil 61 Engine stop fuel injection control means 62 Engine stop decompression valve control means 63 Engine stop intake air amount control means 64 Engine stop starter control means 65 Deceleration fuel injection control means 66 Deceleration decompression valve Control means 67 Start-up decompression valve control means 68 Starter forward rotation drive means 69 Start-up fuel injection control means 70 Starter forward rotation drive means 71 Start point fire control means

Claims (14)

An engine control method for controlling at least the decompression valve and the fuel injection device of an engine including a decompression hole that communicates the inside of each cylinder to the outside, a controllable decompression valve that opens and closes the decompression hole, and a fuel injection device. There,
When the engine is stopped, a fuel cut is performed to stop fuel supply to the engine, and an engine stop control is performed to control the fuel injection device and the decompression valve so as to open the decompression valve. An engine control method characterized by the above.   2. The engine control method according to claim 1, wherein when the engine stop control is performed, the intake air amount adjusting means is controlled so as to simultaneously increase the intake air amount of the engine.   When performing the engine stop control, an air blow cranking for driving a starter motor provided for starting the engine for a set time and maintaining a state where air flows through the decompression hole The engine control method according to claim 1, wherein the engine control method is performed.   When performing the engine stop control, an air blow cranking for driving a starter motor provided to start the engine and maintaining a state where air flows through the decompression hole is performed. 3. The engine control method according to claim 1, wherein the engine control method is performed until the number of rotations of the crankshaft reaches a set value.   The fuel cut is performed also when the engine is decelerated during operation of the engine, and the decompression valve is opened even when the engine is decelerated. The engine control method described.   When starting the engine, the crank angle range suitable for injecting fuel in preparation for the first ignition at the time of starting by rotating the crankshaft of the engine once in the reverse direction with the decompression valve opened. The first-time fuel injection at the start is performed at the crank angle position, and then the start-up control is performed in which the crankshaft is rotated in the positive direction to perform ignition at the crank angle position suitable as the ignition position at the start. The engine control method according to 2, 3, 4 or 5. An engine control device that controls at least the decompression valve and the fuel injection device of an engine including a decompression hole that communicates the inside of the cylinder to the outside, a controllable decompression valve that opens and closes the decompression hole, and a fuel injection device. And
When the engine is stopped, engine stop time fuel injection control means for controlling the fuel injection device so as to perform a fuel cut to stop fuel supply to the engine;
An engine stop decompression valve control means for controlling to open the decompression valve when the engine is stopped;
An engine control device comprising:   The engine stop intake air amount control means for controlling the intake air amount adjusting means so as to simultaneously increase the intake air amount of the engine when performing the engine stop control. 8. The engine control device according to 7.   When performing the engine stop control, an air blow cranking for driving a starter motor provided for starting the engine for a set time and maintaining a state where air flows through the decompression hole 9. The engine control apparatus according to claim 7, further comprising engine stop-time starter motor control means for controlling the starter motor so as to perform the operation.   When performing the engine stop control, an air blow cranking for driving a starter motor provided to start the engine and maintaining a state where air flows through the decompression hole is performed. The engine control device according to claim 7 or 8, further comprising starter motor control means for stopping the engine until the number of rotations of the crankshaft reaches a set value. Decelerating fuel injection control means for controlling the fuel injection device to perform fuel cut when decelerating the engine during operation of the engine;
A decompression decompression valve control means for controlling to open the decompression valve at the time of fuel cut during deceleration of the engine;
The engine control apparatus according to claim 7, further comprising:   A starting decompression valve control means for controlling the opening of the decompression valve when the engine is started and closing the decompression valve when the starting of the engine is completed; and a crankshaft of the engine when the engine is started And a starter reverse rotation driving means for once rotating in the reverse direction and the first fuel injection at the start at the crank angle position in the crank angle range suitable for injecting fuel in preparation for the first ignition at the start. A start-time fuel injection control means for controlling the fuel injection device, a starter forward rotation drive means for rotating the crankshaft in the forward direction after driving of the starter motor by the starter reverse rotation drive means, and an ignition position at start-up And a starting point fire control means for causing an ignition device for igniting the engine at a suitable crank angle position to perform an ignition operation. The engine control apparatus according to any one of claims 7 to 11, characterized in Rukoto.   The said decompression hole is provided so that the inside of each cylinder of the said engine and the cam chamber in which the cam which drives an intake valve and an exhaust valve is arrange | positioned may be connected. Engine starter.   The engine starting device according to any one of claims 7 to 12, wherein the decompression hole is provided so as to allow communication between each cylinder of the engine and an exhaust port.

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