JP2022045482A - Engine device - Google Patents

Abstract

To further stabilize combustion after restoration from a fuel cut.SOLUTION: At restoration from a fuel cut, a direct injection continuation rotation number is set on the basis of a crank rotation counter which is counted up everytime a crankshaft rotates at a prescribed rotation angle during a fuel cut, a cooling water temperature, and an engine load. Then, an engine is controlled so that in-cylinder injection is continuously performed over the set direct injection continuation rotation number. Since the in-cylinder injection can atomize fuel because of injection of the fuel by high combustion pressure compared with port injection, explosion combustion can be stabilized.SELECTED DRAWING: Figure 3

Description

The present invention relates to an engine device, and more particularly to an in-vehicle engine device having a port injection valve and an in-cylinder injection valve.

Conventionally, as an engine device of this type, a device capable of reducing a torque step at the time of returning to a fuel cut has been proposed (see, for example, Patent Document 1). This device diagnoses the failure of the EGR system by forcibly opening and closing the EGR valve during fuel cut. When the elapsed period from the failure diagnosis to the recovery from the fuel cut is short, the ignition timing at the start of the retard control of the ignition timing at the time of returning to the fuel cut is set to the advance side and is delayed as compared with the case where the elapsed period is long. The amount of retardation of the ignition timing at the start of retardation control with respect to the ignition timing immediately before the start of angle control is reduced.

JP-A-2015-158198

Generally, in an engine device, when the duration of fuel cut becomes long, the intake valve and the inside of the cylinder are cooled by the air flowing in the cylinder, and the fuel adhering to the wall surface of the intake valve and the cylinder is also dried. For this reason, the explosive combustion after returning from the fuel cut tends to be unstable, and in some cases, an engine stall occurs.

The main object of the engine device of the present invention is to make combustion more stable after returning from a fuel cut.

The engine device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The engine device of the present invention
An engine having a port injection valve that injects fuel into the intake port and an in-cylinder injection valve that injects fuel into the cylinder,
The control device that controls the engine and
It is an in-vehicle engine device equipped with
When returning from the fuel cut, the control device sets the number of direct injection continuations based on the crank rotation counter that counts up each time the crankshaft rotates by a predetermined rotation angle during the fuel cut, the cooling water temperature, and the engine load. , The engine is controlled so that the in-cylinder injection is continuously performed over the number of continuous direct injections.
It is characterized by that.

In the engine device of the present invention, when returning from the fuel cut, the number of continuous direct injections is based on the crank rotation counter, the cooling water temperature, and the engine load, which counts up every time the crankshaft rotates by a predetermined rotation angle during the fuel cut. To set. Then, the engine is controlled so that the in-cylinder injection is continuously performed for the set number of continuous direct injections. In the recovery from the fuel cut for a long time, selecting the in-cylinder injection is advantageous in the following points as compared with the port injection, so this is selected. First, the temperature inside the cylinder is higher than that of the intake valve because it receives heat from the cooling water flowing around the cylinder even during fuel cutting. Therefore, it is possible to burn with a smaller amount of fuel than port injection. Secondly, the in-cylinder injection injects fuel with a higher fuel pressure than the port injection, so that the fuel can be further atomized. Since the volatility increases due to atomization, combustion is possible with less fuel than port injection. If the temperature of the intake valve rises due to the set number of continuous direct injections, then the advantage of intentionally selecting only direct injection disappears, and the mode shifts to a mode in which another efficient injection form can be adopted. As a result, the combustion of the engine after returning from the fuel cut can be made more stable.

The predetermined angle of rotation may be basically any number of times, but an angle for each combustion, an angle that is an integral multiple of the combustion, or an angle for each cycle is preferable. For example, in the case of a 4-cycle 4-cylinder engine, 180 degrees, 360 degrees, 720 degrees, etc. are suitable, and in the case of a 4-cycle 6-cylinder engine, 120 degrees, 240 degrees, 360 degrees, 720 degrees, etc. are suitable. In the case of a 4-cycle 8-cylinder engine, 90 degrees, 180 degrees, 360 degrees, 720 degrees and the like are suitable. This is because the amount of heat taken from the valve or cylinder is proportional to the number of air passes experienced during the fuel cut. Since the number of intakes during fuel cut in a certain cylinder is completely proportional to the integrated crank angle value, the predetermined rotation angle (integrated) during fuel cut is used instead of the fuel cut time. The number of direct injection continuations assumes the number of in-cylinder injections that is considered necessary for the temperature of the intake valve cooled by the fuel cut to reach the equilibrium state of heat transfer by repeating explosive combustion due to in-cylinder injection. .. As the amount of air flowing into the cylinder during fuel cut increases, the intake valve is cooled, so the number of continuous direct injections increases. Since the amount of air flowing into the cylinder during fuel cut can be reflected as the value of the crank rotation counter that counts up each time the crankshaft rotates at a predetermined rotation angle during fuel cut, the number of direct injection continuations is the crank rotation counter. It can be set so that the larger the integrated value of is, the larger it is. When the cooling water temperature of the engine is low, the temperature of the intake valve is lower because the engine has not warmed up yet near the start of the engine. In addition to cooling during the fuel cut period, the temperature of the intake valve is low due to this unwarmed state, and it takes the number of combustions to reach the equilibrium state of heat transfer, so the number of direct injection continuations increases as the cooling water temperature decreases. Can be set as. Further, the larger the engine load at the time of recovery from the fuel cut, the larger the combustion energy, and the higher the intake valve temperature tends to be. Therefore, the number of continuous direct injections can be set so as to decrease as the engine load increases. Therefore, it is preferable to set the number of continuous direct injections to be larger as the integrated value of the crank rotation counter is larger, larger as the cooling water temperature is lower, and smaller as the engine load is larger.

In such an engine device of the present invention, the control device has a second in-cylinder injection during the first in-cylinder injection set as the direct injection continuation number at the time of returning from the first fuel cut. When returning from the second fuel cut when the fuel cut is performed, the number of times of in-cylinder injection is executed from the first continuation number to the return of the first fuel cut to the start of the second fuel cut. The larger of the remaining number of times after subtracting the above and the second continuation number set as the direct injection continuation number at the time of returning from the second fuel cut may be set as the direct injection continuation number. By doing so, the number of times of continuous direct injection at the time of returning from the second fuel cut can be set more appropriately, and the combustion after returning from the second fuel cut can be made more stable.

In the engine device of the present invention, when the control device performs the intermittent stop of the engine before completing the in-cylinder injection based on the number of continuous direct injections at the time of returning from the fuel cut, the intermittent stop of the engine is performed. At the time of return, the cylinder continues over the correction number obtained by multiplying the remaining number of times the number of in-cylinder injections executed from the fuel cut return to the intermittent stop of the engine from the number of continuous direct injections by the correction coefficient. The engine may be controlled so that internal injection is performed. An operation may be performed to reduce the number of in-cylinder injections executed from the recovery from the fuel cut to the intermittent stop of the engine by multiplication. At the start after the intermittent stop, the number of continuous direct injections may be larger than that of the normal fuel cut return. Therefore, a value slightly larger than the value 1 can be used as the correction coefficient. In this way, by controlling the engine so that the in-cylinder injection is continuously performed over the number of corrections obtained by using the correction coefficient when returning from the intermittent stop of the engine, after returning from the intermittent stop of the engine. The combustion of the engine in the engine can be made more stable.

It is a block diagram which shows the outline of the structure of the hybrid vehicle 20 which mounts the engine device as one Example of this invention. It is a block diagram which shows the outline of the structure of the engine 22 and the fuel supply device 60. It is a flowchart which shows an example of the fuel injection control after the return from the fuel cut executed by the engine ECU 24. Timing chart showing an example of the state of fuel cut, FC elapsed crank counter Cfc, etc. when fuel cut, engine 22, and intermittent stop are not performed again while fuel injection is being executed after returning from fuel cut. Is. Timing that shows an example of the state of the fuel cut, FC elapsed crank counter Cfc, etc. when the fuel cut is executed again while the fuel injection after returning from the fuel cut is being executed and the fuel is returned from the fuel cut again. It is a chart. It is a flowchart which shows an example of the fuel injection control after the return from the fuel cut of a modification. Fuel cut when the volumetric efficiency KL changes significantly due to a change in the amount of depression of the accelerator pedal 83 while executing fuel injection control after returning from the fuel cut, FC elapsed crank counter Cfc, etc. It is a timing chart which shows an example.

Next, an embodiment for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with an engine device as an embodiment of the present invention, and FIG. 2 is a configuration diagram showing an outline of the configuration of an engine 22 and a fuel supply device 60. Is. As shown in FIG. 1, the hybrid vehicle 20 of the embodiment includes an engine 22, a fuel supply device 60, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, and an electronic control unit for a hybrid. It is provided with 70 (hereinafter referred to as “HVECU”). The engine device includes an engine 22, an engine ECU 24, and a fuel supply device 60.

The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or light oil. As shown in FIG. 2, the engine 22 has a port injection valve 125 for injecting fuel into an intake port and an in-cylinder injection valve 126 for injecting fuel into the cylinder. By having the port injection valve 125 and the in-cylinder injection valve 126, the engine 22 can be operated in either the port injection mode or the in-cylinder injection mode. In the port injection mode, the air cleaned by the air cleaner 122 is sucked in through the throttle valve 124, and the fuel is injected from the port injection valve 125 to mix the air and the fuel. Then, this air-fuel mixture is sucked into the combustion chamber via the intake valve 128, explosively burned by the electric spark of the spark plug 130, and the reciprocating motion of the piston 132 pushed down by the energy is converted into the rotational motion of the crankshaft 26. .. In the in-cylinder injection mode, air is sucked into the combustion chamber in the same manner as in the port injection mode, fuel is injected from the in-cylinder injection valve 126 in the middle of the intake stroke or after reaching the compression stroke, and explosive combustion is performed by electric sparks from the spark plug 130. To obtain the rotational movement of the crankshaft 26. These injection modes are switched based on the operating state of the engine 22. Exhaust from the combustion chamber is discharged to the outside air through a purification device 134 having a purification catalyst (three-way catalyst) that purifies harmful components of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). Will be done.

As shown in FIG. 2, the fuel supply device 60 is configured as a device for supplying fuel to the port injection valve 125 and the in-cylinder injection valve 126 of the engine 22. The fuel supply device 60 includes a fuel tank 61, a feed pump (first pump) 62 that supplies fuel from the fuel tank 61 to a low pressure side flow path (first flow path) 63 to which the port injection valve 125 is connected, and a low pressure. The high-pressure side flow path to which the check valve 64 provided in the side flow path 63 and the in-cylinder injection valve 126 are connected by pressurizing the fuel on the port injection valve 125 side of the check valve 64 in the low-pressure side flow path 63. A high-pressure fuel pump (second pump) 65 for supplying to (second flow path) 66 is provided.

The feed pump 62 and the check valve 64 are arranged in the fuel tank 61. The feed pump 62 is configured as an electric pump that operates by receiving electric power supplied from the battery 50. The check valve 64 opens when the fuel pressure (fuel pressure) on the feed pump 62 side in the low pressure side flow path 63 is higher than the fuel pressure on the port injection valve 125 side, and the pressure on the feed pump 62 side is the port injection valve 125. The valve is closed when the fuel pressure on the side is lower than the fuel pressure.

The high-pressure fuel pump 65 is a pump that is driven by power from the engine 22 (rotation of the camshaft) to pressurize the fuel in the low-pressure side flow path 63. The high-pressure fuel pump 65 is connected to its suction port to open and close an electromagnetic valve 65a when pressurizing fuel, and is connected to its discharge port to prevent backflow of fuel and maintain fuel pressure in the high-pressure side flow path 66. It has a check valve 65b and a check valve 65b. The high-pressure fuel pump 65 sucks fuel from the feed pump 62 when the electromagnetic valve 65a is opened while the engine 22 is in operation, and is powered by the engine 22 when the electromagnetic valve 65a is closed. The fuel supplied to the high-pressure side flow path 66 is pressurized by intermittently feeding the fuel compressed by the operating plunger by a plunger (not shown) into the high-pressure side flow path 66 via the check valve 65b. When the high-pressure fuel pump 65 is driven, the fuel pressure in the low-pressure side flow path 63 and the fuel pressure in the high-pressure side flow path 66 pulsate according to the rotation of the engine 22 (rotation of the camshaft).

The engine 22 and the fuel supply device 60 are operated and controlled by an engine electronic control unit (hereinafter, referred to as “engine ECU”) 24. Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. ..

Signals from various sensors necessary for controlling the operation of the engine 22 and controlling the fuel supply device 60 are input to the engine ECU 24 via the input port. The signals input to the engine ECU 24 include, for example, the crank position θcr from the crank position sensor 140 that detects the rotational position of the crankshaft 26, and the cooling water temperature Tw from the water temperature sensor 142 that detects the temperature of the cooling water of the engine 22. Can be mentioned. Further, the cam position θca from the cam position sensor 144 that detects the rotational position of the intake camshaft that opens and closes the intake valve 128 and the exhaust camshaft that opens and closes the exhaust valve can also be mentioned. Further, the throttle opening TH from the throttle valve position sensor 146 that detects the position of the throttle valve 124, the intake air amount Qa from the air flow meter 148 attached to the intake pipe, and the temperature sensor 149 attached to the intake pipe. The intake air temperature Ta can also be mentioned. In addition, the air-fuel ratio AF from the air-fuel ratio sensor 135a attached to the exhaust pipe and the oxygen signal O2 from the oxygen sensor 135b attached to the exhaust pipe can also be mentioned. Further, the rotation speed Nfp of the feed pump 62 from the rotation speed sensor 62a attached to the feed pump 62 of the fuel supply device 60, and the port from the fuel pressure sensor 68 attached to the vicinity of the port injection valve 125 in the low pressure side flow path 63. The fuel pressure Pfp of the fuel supplied to the injection valve 125 and the fuel pressure Pfd of the fuel supplied to the in-cylinder injection valve 126 from the fuel pressure sensor 69 attached in the vicinity of the in-cylinder injection valve 126 in the high-pressure side flow path 66 can also be mentioned.

Various control signals for controlling the operation of the engine 22 and controlling the fuel supply device 60 are output from the engine ECU 24 via the output port. The signals output from the engine ECU 24 include, for example, a drive signal to the port injection valve 125, a drive signal to the in-cylinder injection valve 126, a drive signal to the throttle motor 136 for adjusting the position of the throttle valve 124, and an igniter. A control signal to the modified ignition coil 138 can be mentioned. Further, a drive control signal to the feed pump 62 and a drive control signal to the solenoid valve 65a of the high-pressure fuel pump 65 can also be mentioned.

The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr from the crank position sensor 140. Further, the engine ECU 24 has a volumetric efficiency (volume of air actually sucked in one cycle with respect to the stroke volume per cycle of the engine 22) based on the amount of air taken in from the air flow meter 148 Qa and the rotation speed Ne of the engine 22. Ratio) KL is calculated.

As shown in FIG. 1, the planetary gear 30 is configured as a single pinion type planetary gear mechanism. A rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. A drive shaft 36 connected to the drive wheels 39a and 39b via a differential gear 38 is connected to the ring gear of the planetary gear 30. The crankshaft 26 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28.

The motor MG1 is configured as, for example, a synchronous motor generator, and as described above, the rotor is connected to the sun gear of the planetary gear 30. The motor MG2 is configured as, for example, a synchronous motor generator, and a rotor is connected to a drive shaft 36. The inverters 41 and 42 are connected to the motors MG1 and MG2 and are connected to the battery 50 via the power line 54. The motors MG1 and MG2 are rotationally driven by switching control of a plurality of switching elements (not shown) of the inverters 41 and 42 by an electronic control unit for a motor (hereinafter referred to as "motor ECU") 40.

Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. .. The motor ECU 40 has signals from various sensors necessary for driving and controlling the motors MG1 and MG2, for example, rotation positions θm1 from rotation position detection sensors 43 and 44 that detect the rotation positions of the rotors of the motors MG1 and MG2. , Θm2, the temperature tm2 of the motor MG2 from the temperature sensor that detects the temperature of the motor MG2, and the like are input via the input port. From the motor ECU 40, switching control signals and the like to a plurality of switching elements (not shown) of the inverters 41 and 42 are output via the output port. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 calculates the rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotation positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotation position detection sensors 43 and 44.

The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and is connected to the inverters 41 and 42 via a power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter, referred to as “battery ECU”) 52.

Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. .. Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input port. The signals input to the battery ECU 52 include, for example, the battery voltage Vb from the voltage sensor 51a installed between the terminals of the battery 50, the battery current Ib from the current sensor 51b attached to the output terminal of the battery 50, and the battery 50. The battery temperature Tb from the temperature sensor 51c attached to the above can be mentioned. The battery ECU 52 is connected to the HVECU 70 via a communication port. The battery ECU 52 calculates the storage ratio SOC based on the integrated value of the battery current Ib from the current sensor 51b. The storage ratio SOC is the ratio of the capacity of electric power that can be discharged from the battery 50 to the total capacity of the battery 50.

Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. Signals from various sensors are input to the HVECU 70 via the input port. Examples of the signal input to the HVECU 70 include an ignition signal from the ignition switch 80 and a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81. Further, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed sensor 88. The vehicle speed V and the outside air temperature Tout from the outside temperature sensor 89 can also be mentioned. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via a communication port.

In the hybrid vehicle 20 of the embodiment configured in this way, the required driving force of the drive shaft 36 is set based on the accelerator opening degree Acc and the vehicle speed V, and the required power corresponding to the required driving force is output to the drive shaft 36. In addition, the engine 22 and the motors MG1 and MG2 are operated and controlled. The operation modes of the engine 22 and the motors MG1 and MG2 include the following modes (1) to (3).
(1) Torque conversion operation mode: The engine 22 is operated and controlled so that the power corresponding to the required power is output from the engine 22, and all the power output from the engine 22 is the planetary gear 30 and the motors MG1 and MG2. A mode in which the motors MG1 and MG2 are driven and controlled so that the required power is output to the drive shaft 36 after being torque-converted by (2) Charge / discharge operation mode: The sum of the required power and the power required for charging / discharging the battery 50. The engine 22 is operated and controlled so that the power corresponding to the above is output from the engine 22, and all or part of the power output from the engine 22 is charged and discharged from the battery 50 to the planetary gear 30 and the motors MG1 and MG2. Mode in which the motors MG1 and MG2 are driven and controlled so that the required power is output to the drive shaft 36 by torque conversion by (3) Motor operation mode: The operation of the engine 22 is stopped and the required power is sent to the drive shaft 36. Mode to drive and control the motor MG2 so that it is output

Further, in the hybrid vehicle 20 of the embodiment, when the engine 22 is operated, the engine ECU 24 controls the intake air amount control, the fuel injection control, the feed pump 62 of the fuel supply device 60, and the high pressure fuel pump 65.

In the intake air amount control, first, the target air amount Qa * is set based on the target torque Te * of the engine 22. Subsequently, the target throttle opening TH * is set so that the intake air amount Qa becomes the target air amount Qa *. Then, the throttle motor 136 is controlled so that the throttle opening degree TH becomes the target throttle opening degree TH *.

In the fuel injection control, first, the port injection mode, the in-cylinder injection mode, and the execution injection mode are set based on the rotation speed Ne of the engine 22 and the volumetric efficiency KL. Subsequently, the target injection amount of the port injection valve 125 or the in-cylinder injection valve 126 so that the air-fuel ratio AF becomes the target air-fuel ratio AF * (for example, the theoretical air-fuel ratio) based on the target air amount Qa * and the execution injection mode. Set Qfp * and Qfd *. Then, the target injection time τfp *, τfd * of the port injection valve 125 or the in-cylinder injection valve 126 is set based on the target injection amounts Qfp * and Qfd * and the fuel pressures Pfp and Pfd. When the target injection times τfp * and τpd * are set in this way, the in-cylinder injection valve 126 or the port injection valve 125 so that the fuel injection of the target injection times τfp *, τfd * is performed from the in-cylinder injection valve 126 or the port injection valve 125. To control.

In the control of the feed pump 62, first, the feed pump is based on the target fuel pressure Pfp * of the fuel supplied to the port injection valve 125 and the target injection amounts Qfp * and Qfd * of the port injection valve 125 or the in-cylinder injection valve 126. The target discharge amount Qpp * of 62 is set. Here, in the embodiment, the target fuel pressure Pfp * is set to a relatively high predetermined fuel pressure Pfp1 at the start of operation of the engine 22, and when the predetermined time T1 elapses, the target fuel pressure Pfp * is switched to a predetermined fuel pressure Pfp2 lower than the predetermined fuel pressure Pfp1. .. As the predetermined fuel pressure Pfp1, for example, about 500 kPa to 550 kPa is used, and as the predetermined fuel pressure Pfp2, for example, about 380 kPa to 420 kPa is used. As the predetermined time T1, for example, about 5 seconds to 7 seconds is used. Further, in the embodiment, the target discharge amount Qpp * is set so as to increase as the target fuel pressure Pfp * increases. When the target discharge amount Qpp * is set in this way, the feed pump 62 is controlled so that the discharge amount (fuel amount) from the feed pump 62 becomes the target discharge amount Qpp *.

In the control of the high-pressure fuel pump 65, first, the target discharge amount Qpd * of the high-pressure fuel pump 65 is set based on the target fuel pressure Pfd * of the fuel supplied to the in-cylinder injection valve 126. Here, as the target fuel pressure Pfd *, for example, about several MPa to a dozen MPa is used. In the embodiment, the target discharge amount Qpd * is set so as to increase as the target fuel pressure Pfd * increases and as the target injection amount Qfd * increases. When the target discharge amount Qpd * is set in this way, the electromagnetic valve 65a of the high-pressure fuel pump 65 is controlled so that the discharge amount (fuel amount) from the high-pressure fuel pump 65 becomes the target discharge amount Qpd *.

Next, the operation of the hybrid vehicle 20 of the embodiment configured in this way, particularly the fuel injection control after returning from the fuel cut will be described. FIG. 3 is a flowchart showing an example of fuel injection control after returning from the fuel cut executed by the engine ECU 24 of the embodiment. This process is executed when returning from the fuel cut.

When the fuel injection control after returning from the fuel cut is executed, the engine ECU 24 first inputs data such as the FC elapsed crank counter Cfc, the temperature Tw of the cooling water of the engine 22, and the volumetric efficiency KL (step S100). .. In the embodiment, the FC elapsed crank counter Cfc is a counter that counts up every time the crankshaft 26 rotates by a predetermined rotation angle from the start of the fuel cut to the return of the fuel cut, and after the return from the fuel cut. The value is reset to 0 when the fuel injection control of is finished. The predetermined angle of rotation may be basically any number of times, but an angle for each combustion, an angle that is an integral multiple of the combustion, or an angle for each cycle is preferable. For example, in the case of a 4-cycle 4-cylinder engine, 180 degrees, 360 degrees, 720 degrees, etc. are suitable, and in the case of a 4-cycle 6-cylinder engine, 120 degrees, 240 degrees, 360 degrees, 720 degrees, etc. are suitable. In the case of a 4-cycle 8-cylinder engine, 90 degrees, 180 degrees, 360 degrees, 720 degrees and the like are suitable. This is because the amount of heat taken from the valve or cylinder is proportional to the number of air passes experienced during the fuel cut. Since the number of intakes during fuel cut in a certain cylinder is completely proportional to the integrated crank angle value, the predetermined rotation angle (integrated) during fuel cut is used instead of the fuel cut time. Hereinafter, in the embodiment, the engine 22 is a 4-cycle 4-cylinder engine, and 180 degrees is used as a predetermined rotation angle so that the number of combustions is obtained if the value of the FC planning rank counter Cfc is fuel-injected. The temperature Tw of the cooling water of the engine 22 was input to be detected by the temperature sensor 142. Further, the volumetric efficiency KL is calculated by the engine ECU 24 based on the intake air amount Qa from the air flow meter 148 and the rotation speed Ne of the engine 22, and the volumetric efficiency KL is the engine 22. Since it is the ratio of the volume of air actually sucked in one cycle to the stroke volume per cycle, it is consistent with the load of the engine 22.

Subsequently, the temporary direct injection continuation number Ntmp is set based on the input FC elapsed crank counter Cfc, the temperature Tw of the cooling water of the engine 22, and the volumetric efficiency KL (step S110), and the temporary direct injection continuation number Ntmp and the residual number Nd are set. The larger of the above is set as the number of direct injection continuation times Nfc (step S120). The direct injection continuation number Nfc is the number of times the fuel is injected in the in-cylinder injection mode after returning from the fuel cut, and when the residual number Nd is the initial value 0, the provisional direct injection continuation number Ntmp is set. Therefore, the direct injection continuation number Nfc is set based on the FC elapsed crank counter Cfc, the temperature Tw of the cooling water of the engine 22, and the volumetric efficiency KL. In step S110, in the embodiment, the relationship between the FC elapsed crank counter Cfc, the temperature Tw of the cooling water of the engine 22, the volumetric efficiency KL, and the direct injection continuation number Nfc is determined in advance by an experiment or the like, and a map for setting the direct injection continuation number. Given the FC elapsed crank counter Cfc, the temperature Tw of the cooling water of the engine 22, and the volumetric efficiency KL, the corresponding direct injection continuation number Nfc is derived from the map, and this is used as the provisional direct injection continuation number Ntmp. Set as. The remaining number of times Nd will be described later.

Subsequently, the in-cylinder injection mode is set as the execution injection mode (step S130), and the count-up of the injection count N after the return is started (step S140). The number of injections N after return is the number of fuel injections after returning from the fuel cut, and is counted up every time fuel injection is performed from the initial value of 0.

Next, it is determined whether or not the fuel cut is performed (step S150). That is, it is determined whether or not the fuel cut is performed again while the fuel injection control after returning from the fuel cut is being executed. Consider the case where the fuel cut is not performed again while this control is being executed. In this case, it is determined that the fuel cut has not been performed in step S150, and it is determined whether or not the engine 22 is intermittently stopped as the next process (step S160). Consider the case where the engine 22 is not intermittently stopped. In this case, it is determined whether or not the number of injections N after the return in step S210 is equal to or greater than the number of continuous direct injections Nfc. When it is determined that the number of injections N after the return is less than the number of continuous direct injections Nfc, the process returns to the determination of whether or not the fuel is cut in step S150. Now, since we are considering a case where neither fuel cut nor intermittent stop of the engine 22 is performed while this control is being executed, in the processing of steps S150 to S210, the direct injection number N continues after the return. It is a process of waiting until the number of times Nfc is reached. That is, when returning from the fuel cut, the engine 22 is continuously controlled by the in-cylinder injection in the in-cylinder injection mode until the number of injections N after the return reaches the number of continuous direct injections Nfc. Since the fuel injection amount at this time is the fuel injection after the return from the fuel cut, the increase correction is calculated based on the duration Tcut of the fuel cut and the elapsed time Taft after the return from the fuel cut, and the in-cylinder. The target injection amount Qfd * of the injection valve 126 is increased and corrected.

When it is determined in step S210 that the number of injections N after returning has reached the number of continuous direct injections Nfc, the normal setting for setting the execution injection mode to the port injection mode or the in-cylinder injection mode based on the operating state of the engine 22 or the like. (Step S220). Then, the remaining number of times Nd is reset to the value 0 (step S230), and the FC elapsed crank counter Cfc and the return injection number N are reset to the initial value value 0 (step S250), and this control is terminated. In this way, the combustion of the engine 22 is made more stable by continuing the in-cylinder injection until the number of fuel injections (number of injections after return N) reaches Nfc after the return from the fuel cut. It is possible to suppress the occurrence of engine stall.

When it is determined that the fuel cut is performed in step S150, the value obtained by subtracting the number of injections N after returning from the number of continuous direct injections Nfc is calculated as the remaining number Nd (step S240). Then, the FC elapsed crank counter Cfc and the number of injections N after returning are reset to the initial value of 0 (step S250), and this control is terminated. In this case, this control is executed when the fuel cut is restored, and in step S120, the larger of the temporary direct injection continuation number Ntmp and the residual number Nd is set as the direct injection continuation number Nfc. Now, consider a case where the main control is started by recovering from the fuel cut over a relatively long time, the fuel cut is performed again in a short time after the recovery, and the fuel cut is recovered in a short time. In this case, a relatively large number of direct injection continuations Nfc is set by the fuel cut over a relatively long time, and a relatively large number of direct injection continuations Nfc is returned from the relatively large number of direct injection continuations Nfc by performing the fuel cut again in a short time after the return. The remaining number of times Nd, which is a relatively large value, is calculated by subtracting the number of times N of post-injection. On the other hand, since the fuel cut is restored in a short time, the FC elapsed crank counter Cfc becomes a small value, and the temporary direct injection continuation number Ntmp set in step S110 also becomes a small value. Therefore, in step S120, the small value of the temporary direct injection continuation number Ntpp and the large value of the residual number Nd are size-compared. Therefore, the residual number Nd is set in the direct injection continuation number Nfc, and the fuel is cut again. At the time of return, the in-cylinder injection mode is continued until the fuel is injected by the remaining number of times Nd. That is, the residual number Nd, which is the residual number of injections when continuing the in-cylinder injection after returning from the fuel cut over a relatively long time, is calculated, and after returning from the short-time fuel cut, the inside of the cylinder is calculated. The injection is continued for the remaining number of times Nd. When the fuel cut is performed again for a relatively long time, a relatively large number of temporary direct injection continuation times Ntmp is set. Is set as. From these facts, the remaining number of times Nd is the continuation of direct injection after the return from the fuel cut when the fuel cut is performed again while the fuel injection control after the return from the fuel cut is being executed. It can be seen that it functions as a lower limit guard when setting the number of times Nfc.

When it is determined in step S160 that the engine 22 is intermittently stopped, a value obtained by subtracting the number of injections N after returning from the number of continuous direct injections Nfc is calculated as the remaining number Nd (step S170). Subsequently, the direct injection continuation number Nfc is calculated by multiplying the residual number Nd by the correction coefficient kf (step S180), the return degree continuation number N is reset to a value 0, and the reset count of the return degree continuation number N is started. (Step S190), waiting for the engine 22 to return from the intermittent stop (step S200). After returning from the intermittent stop of the engine 22, a process of waiting for the return degree continuation number N in steps S150 to S210 to reach the direct injection continuation number Nfc is executed. At this time, the in-cylinder injection is continued by the newly set number of direct injection continuation times Nfc (the number of times the remaining number Nd is multiplied by the correction coefficient kf). After returning from the fuel cut, the temperature of the intake valve 126 rises due to the in-cylinder injection and combustion, but the heat of the intake valve 126 escapes due to the intermittent stop of the engine, so the effect of N times in-cylinder injection Is reduced. Therefore, it is necessary to slightly increase the number of direct injection continuation times Nfc after returning from the intermittent stop of the engine 22 to the remaining number of times Nd. Therefore, in the embodiment, a value slightly larger than the value 1 (for example, 1.1 or 1.2) is used as the correction coefficient kf.

FIG. 4 shows the fuel cut when the fuel injection control after the return from the fuel cut is being executed and the fuel cut and the intermittent stop of the engine 22 are not performed, the FC elapsed crank counter Cfc, and the injection after the return. It is a timing chart which shows an example of the state of the number of times N, the continuation state of in-cylinder injection. During the fuel cut (ON), the FC elapsed crank counter Cfc becomes larger according to the rotation speed integration of the crankshaft 26. At the time T11 after returning (OFF) from the fuel cut, the in-cylinder injection mode is set (ON) to the execution injection mode and the direct injection continuation number Nfc is set. Then, each time the fuel is injected into the cylinder, the return degree injection number N is counted up. At the time T12 when the return degree injection number N reaches the direct injection continuation number Nfc, the return degree injection number N and the FC elapsed crank counter Cfc are reset, the in-cylinder injection mode is canceled (OFF), and the execution injection mode is the engine. It is a normal setting in which the in-cylinder injection mode or the port injection mode is set according to the operating state of 22 and the like. In this way, the combustion of the engine 22 is made more stable by continuing the in-cylinder injection until the number of fuel injections (number of injections after return N) reaches Nfc after the return from the fuel cut. It is possible to suppress the occurrence of engine stall.

In FIG. 5, the fuel cut is executed again while the fuel injection control after the return from the fuel cut is being executed, and the fuel cut when returning from the refuel cut, the FC elapsed crank counter Cfc, and after the return are shown. It is a timing chart which shows an example of the state of the injection number N and the continuation state of in-cylinder injection. At the time T21 after returning from the fuel cut, the in-cylinder injection mode is set (ON) to the execution injection mode, and the direct injection continuation number Nfc is set. Then, each time the fuel is injected into the cylinder, the return degree injection number N is counted up. At the time T22 when the fuel cut is started again before the return injection number N reaches the direct injection continuation number Nfc, the residual number Nd is calculated by subtracting the return injection number N from the direct injection continuation number Nfc. Further, the return degree injection number N and the FC elapsed crank counter Cfc are reset, and the in-cylinder injection mode is canceled (OFF). After that, during the fuel cut, the FC elapsed crank counter Cfc becomes larger according to the rotation of the crankshaft 26. At the time T32 after returning from the fuel cut again, the in-cylinder injection mode is set (ON) to the execution injection mode and the direct injection continuation number Nfc is set. At this time, since the remaining number Nd functions as the lower limit guard, the remaining number Nd is set to the direct injection continuation number Nfc in the case of a short-time fuel cut. Then, each time the fuel is injected into the cylinder, the return degree injection number N is counted up. At the time T24 when the return degree injection number N reaches the direct injection continuation number Nfc, the in-cylinder injection mode is canceled (OFF).

In the engine device mounted on the hybrid vehicle 20 of the embodiment described above, when returning from the fuel cut, the FC elapsed crank counter Cfc and the engine 22 count up each time the crankshaft 26 rotates at a predetermined rotation angle during the fuel cut. The direct injection continuation number Nfc is set based on the cooling water temperature Tw and the load of the engine 22 (volumetric efficiency KL), and the in-cylinder injection mode is continuously applied until the injection number N after the return reaches the direct injection continuation number Nfc. The engine 22 is controlled so that in-cylinder injection is performed. As a result, the combustion after returning from the fuel cut can be made more stable, and the occurrence of engine stall can be suppressed.

In the engine device mounted on the hybrid vehicle 20 of the embodiment, when the fuel injection is performed again while the fuel injection control after the return from the fuel cut is being executed, the direct injection continuation number Nfc is used for the injection after the return. The remaining number Nd is calculated by subtracting the number N, and the remaining number Nd is made to function as a lower limit guard when setting the direct injection continuation number Nfc after returning from the fuel cut again. As a result, the number of times the in-cylinder injection is continued after returning from the fuel cut can be made more appropriate, and the combustion after returning from the fuel cut can be made more stable. ..

In the engine device mounted on the hybrid vehicle 20 of the embodiment, when the engine 22 is intermittently stopped while the fuel injection control after the return from the fuel cut is being executed, the direct injection continuation number Nfc is changed to the injection number N after the return. The value obtained by subtracting is calculated as the remaining number of times Nd, and the remaining number of times Nd is multiplied by the correction coefficient kf to calculate the direct injection continuation number Nfc. Then, the return degree continuation number N is reset to a value 0, and the count of the reset degree continuation number N is started, and the return degree continuation number N reset after the return from the intermittent stop of the engine 22 is newly set. In-cylinder injection is continued in the in-cylinder injection mode for the number of times of continuous direct injection Nfc. As a result, it is possible to take more appropriate measures when the engine 22 is intermittently stopped while the in-cylinder injection after returning from the fuel cut is being continued.

In the engine device mounted on the hybrid vehicle 20 of the embodiment, the direct injection continuation number Nfc was set based on the volumetric efficiency KL at the time of returning from the fuel cut. However, when the volumetric efficiency KL changes significantly due to a change in the amount of depression of the accelerator pedal 83 during execution of fuel injection control after returning from the fuel cut, direct injection is performed based on the changed volumetric efficiency. The continuation number Nfc may be reset. In this case, instead of the fuel injection control after the return from the fuel cut in FIG. 3, the fuel injection control after the return from the fuel cut in FIG. 6 may be executed. Since the fuel injection control after returning from the fuel cut in FIG. 6 is the fuel injection control after returning from the fuel cut in FIG. 3, the processes of S142 to S148 are added between the processes of steps S140 and S150. , The processing of steps S100 to S130 and the processing of steps S160 to S200 are not shown.

In the fuel injection control after returning from the fuel cut in FIG. 6, while waiting for the injection number N after returning to reach the direct injection continuation number Nfc, the volumetric efficiency KL is input to return from the fuel cut. The amount of change ΔKL from time is calculated (step S142), and it is determined whether or not the absolute value of the amount of change ΔKL is equal to or greater than the threshold value KLref (step S144). Here, the threshold value KLref is a threshold value for determining when the amount of change ΔKL from the time of recovery from the fuel cut is so large that it cannot be ignored, and a value such as 30% or 40% with respect to the maximum value of the volumetric efficiency KL is used. be able to. When it is determined that the absolute value of the amount of change ΔKL is less than the threshold value KLref, the process proceeds to step S150. On the other hand, when it is determined that the absolute value of the change amount ΔKL is equal to or higher than the threshold value KLref, the temporary direct injection continuation number Ntmp is reset based on the FC elapsed crank counter Cfc, the temperature Tw of the cooling water of the engine 22, and the volumetric efficiency KL. (Step S146), the larger of the temporary direct injection continuation number Ntmp and the residual number Nd is reset as the direct injection continuation number Nfc (step S148).

FIG. 7 shows the fuel cut and FC elapsed crank counter Cfc when the volumetric efficiency KL changes significantly due to a change in the amount of depression of the accelerator pedal 83 during execution of fuel injection control after returning from the fuel cut. , N is the number of injections after the return, and is a timing chart showing an example of the state of continuation of in-cylinder injection. In the figure, the broken line after the time T33 shows the state when there is no significant change in the volumetric efficiency KL. At the time T31 after returning from the fuel cut, the in-cylinder injection mode is set (ON) to the execution injection mode, and the direct injection continuation number Nfc is set. Then, each time the fuel is injected into the cylinder, the return degree injection number N is counted up. When the accelerator pedal 83 is depressed at the time T32 and the volumetric efficiency KL changes significantly, the direct injection continuation number Nfc is reset. At the time T33 when the direct injection continuation number Nfc in which the return injection number N is reset is reached, the return injection number N and the FC elapsed crank counter Cfc are reset, and the in-cylinder injection mode is canceled (OFF). If there is no significant change in the volumetric efficiency KL, the return degree injection number N and the FC elapsed crank are set at the time T34 when the return degree injection number N reaches the direct injection continuation number Nfc set at the time of recovery from the fuel cut. The counter Cfc is reset and the in-cylinder injection mode is canceled (OFF). In this way, when the volumetric efficiency KL changes significantly due to a change in the amount of depression of the accelerator pedal 83 during fuel injection control after returning from the fuel cut, the number of direct injection continuations Nfc is re-introduced. By setting it, it is possible to deal with a large change in volumetric efficiency KL.

In the hybrid vehicle 20 of the embodiment, the battery 50 is used as the power storage device, but any device that can store electricity may be used, and a capacitor or the like may be used.

Although the hybrid vehicle 20 of the embodiment includes the engine ECU 24, the motor ECU 40, the battery ECU 52, and the HVECU 70, at least two of them may be configured as a single electronic control unit.

In the hybrid vehicle 20 of the embodiment, the engine 22 and the motor MG1 are connected to the drive shaft 36 connected to the drive wheels 39a and 39b via the planetary gear 30, and the motor MG2 is connected to the drive shaft 36 to connect the motors MG1 and MG2. The battery 50 is connected via a power line. However, it may be a configuration of a so-called one-motor hybrid vehicle, a configuration of a so-called series hybrid vehicle, or a configuration of a so-called ordinary gasoline vehicle.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the port injection valve 125 corresponds to the "port injection valve", the in-cylinder injection valve 126 corresponds to the "in-cylinder injection valve", the engine 22 corresponds to the "engine", and the engine ECU 24 corresponds to the "control device". Is equivalent to.

As for the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problems of the examples is carried out. Since it is an example for specifically explaining the mode for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments and may be in various embodiments within the scope of the gist of the present invention. Of course it can be done.

The present invention can be used in the manufacturing industry of engine devices and the like.

20 hybrid car, 22 engine, 24 engine ECU, 26 crank shaft, 28 damper, 30 planetary gear, 36 drive shaft, 38 differential gear, 39a, 39b drive wheel, 40 motor ECU, 41,42 inverter, 43,44 rotation position detection Sensor, 50 battery, 51a voltage sensor, 51b current sensor, 51c temperature sensor, 52 battery ECU, 54 power line, 60 fuel supply device, 61 fuel tank, 62 feed pump, 62a rotation speed sensor, 63 low pressure side flow path, 64 Check valve, 65 high pressure fuel pump, 65a electromagnetic valve, 65b check valve, 66 high pressure side flow path, 68 fuel pressure sensor, 69 fuel pressure sensor, 70 HVECU, 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal , 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 89 outside temperature sensor, 122 air cleaner, 124 throttle valve, 125 port injection valve, 126 in-cylinder injection valve, 128 intake valve, 130 ignition Plug, 132 piston, 134 purification device, 135a air fuel ratio sensor, 135b oxygen sensor, 136 throttle motor, 138 ignition coil, 140 crank position sensor, 142 water temperature sensor, 144 cam position sensor, 146 throttle valve position sensor, 148 air flow meter, 149 temperature sensor, MG1, MG2 motor.

Claims (1)

An engine having a port injection valve that injects fuel into the intake port and an in-cylinder injection valve that injects fuel into the cylinder,
The control device that controls the engine and
It is an in-vehicle engine device equipped with
When returning from the fuel cut, the control device sets the number of direct injection continuations based on the crank rotation counter that counts up each time the crankshaft rotates by a predetermined rotation angle during the fuel cut, the cooling water temperature, and the engine load. , The engine is controlled so that the in-cylinder injection is continuously performed over the number of continuous direct injections.
An engine device characterized by that.

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