JP7405045B2 - engine equipment - Google Patents

Description

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

BACKGROUND ART Conventionally, as this type of engine device, one that can reduce the torque step difference at the time of return from fuel cut has been proposed (see, for example, Patent Document 1). This device performs failure diagnosis of the EGR system by forcibly opening and closing the EGR valve during fuel cut. When the elapsed period from failure diagnosis to fuel cut recovery is short, the ignition timing at the start of retard control of the ignition timing at the time of fuel cut recovery is advanced and retarded compared to when the elapsed period is long. The amount of retardation of the ignition timing at the start of the retard control with respect to the ignition timing immediately before the start of the angle control is reduced.

Japanese Patent Application Publication No. 2015-158198

Generally, in an engine system, when a fuel cut continues for a long time, the air flowing into the cylinder cools the intake valve and the inside of the cylinder, and the fuel adhering to the wall of the intake valve and the inside of the cylinder also dries up. For this reason, explosive combustion after recovery from a fuel cut tends to become unstable, and in some cases, the engine stalls.

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

The engine device of the present invention employs the following means to achieve the above-mentioned main purpose.

The engine device of the present invention includes:
An engine having a port injection valve that injects fuel into an intake port and an in-cylinder injection valve that injects fuel into a cylinder;
a control device that controls the engine;
An in-vehicle engine device comprising:
When returning from a fuel cut, the control device sets the number of continuous direct injections based on a crank rotation counter that counts up every time the crankshaft rotates a predetermined rotation angle during the fuel cut, the cooling water temperature, and the engine load. , controlling the engine so that in-cylinder injection continues for the number of continuous direct injections;
It is characterized by

In the engine device of the present invention, when returning from a fuel cut, the number of continuous direct injections is determined based on the crank rotation counter that counts up every time the crankshaft rotates by a predetermined rotation angle during the fuel cut, the cooling water temperature, and the engine load. Set. Then, the engine is controlled so that in-cylinder injection continues for the set number of direct injection continuations. When recovering from a long fuel cut, in-cylinder injection is selected because it has the following advantages over port injection. 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 cut. Therefore, compared to port injection, combustion is possible with a smaller amount of fuel. Second, compared to port injection, in-cylinder injection injects fuel at a higher fuel pressure and can therefore make the fuel more atomized. Since atomization increases volatility, combustion is possible with less fuel compared to port injection. Once the temperature of the intake valve rises due to combustion for the set number of continuous direct injections, there is no longer any advantage to intentionally selecting only direct injection, and the mode shifts to a mode that allows other efficient injection forms. As a result, combustion in the engine after recovery from fuel cut can be made more stable.

Basically, the predetermined rotation angle may be any number of times, but it is preferably an angle for each combustion, an angle that is an integral multiple of the combustion, or an angle for each cycle. 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-stroke 8-cylinder engine, 90 degrees, 180 degrees, 360 degrees, 720 degrees, etc. are suitable. This is because the amount of heat removed from the valves and the inside of the cylinder is proportional to the number of air passages experienced during the fuel cut. Since the number of intakes during fuel cut in a certain cylinder is completely proportional to the crank angle integrated value, the predetermined rotation angle (integrated) during fuel cut is used instead of the fuel cut time. The number of continuous direct injections is assumed to be the number of in-cylinder injections considered necessary until the temperature of the intake valve, which has been cooled by the fuel cut, reaches an equilibrium state of heat exchange through repeated explosive combustion due to in-cylinder injection. . The larger the amount of air that flows into the cylinder during fuel cut, the more the intake valves are cooled, which increases the number of times direct injection continues. The amount of air flowing into the cylinder during fuel cut can be reflected as the value of the crank rotation counter, which counts up every time the crankshaft rotates a predetermined rotation angle during fuel cut, so the number of continuous direct injections can be calculated by the crank rotation counter. It can be set so that the larger the integrated value is, the larger the integrated value is. When the engine coolant temperature is low, the intake valve temperature is lower because the engine is about to start and the engine has not yet warmed up. In addition to cooling during the fuel cut period, the temperature of the intake valve is low due to this lack of warming, and it takes a number of combustion cycles to reach an equilibrium state of heat exchange, so the number of continuous direct injection increases as the cooling water temperature decreases. It can be set as follows. Furthermore, the greater the engine load upon recovery from a fuel cut, the greater the combustion energy, and the more likely the intake valve temperature will rise. Therefore, the number of continuous direct injections can be set to decrease as the engine load increases. Therefore, it is preferable to set the number of direct injection continuations such that the number increases as the integrated value of the crank rotation counter increases, increases as the cooling water temperature decreases, and decreases as the engine load increases.

In such an engine device of the present invention, the control device may perform a second direct injection while the direct injection is being performed for the first number of continuations set as the number of continuations of the direct injection at the time of recovery from the first fuel cut. When returning from the second fuel cut when a fuel cut is performed, the number of in-cylinder injection executions from the first number of continuations to the start of the second fuel cut. The number of continuous direct injections may be set to be the larger of the remaining number of times after subtracting the number of direct injections and the second number of continuous injections set as the number of continuous direct injections when returning from the second fuel cut. In this way, the number of continuous direct injections upon recovery from the second fuel cut can be set more appropriately, and combustion after recovery from the second fuel cut can be made more stable.

In the engine device of the present invention, when the engine is stopped intermittently before completing the in-cylinder injection based on the number of continuous direct injections when returning from a fuel cut, the control device is configured to stop the engine from the intermittent stop. At the time of recovery, the direct injection continues for the number of corrections obtained by multiplying the remaining number of direct injections executed from the fuel cut return to the intermittent stop of the engine by the correction coefficient from the number of continuous direct injections. The engine may be controlled so that internal injection is performed. Calculation may be performed to reduce the number of in-cylinder injections executed from the time the fuel cut is returned to the time when the engine is stopped intermittently by multiplication. When starting after an intermittent stop, the number of continuous direct injections may be greater than the number of times during normal fuel cut recovery. Therefore, a value slightly larger than 1 can be used as the correction coefficient. In this way, by controlling the engine so that in-cylinder injection continues for the number of corrections obtained using the correction coefficient when the engine returns from intermittent stop, The combustion of the engine can be made more stable.

1 is a configuration diagram schematically showing the configuration of a hybrid vehicle 20 equipped with an engine device as an embodiment of the present invention. 2 is a configuration diagram schematically showing the configuration of an engine 22 and a fuel supply device 60. FIG. It is a flowchart which shows an example of fuel injection control after recovery from fuel cut performed by engine ECU24. Timing chart showing an example of the state of fuel cut, FC elapsed crank counter Cfc, etc. when neither fuel cut again nor intermittent stop of the engine 22 is performed during execution of fuel injection after recovery from fuel cut It is. Timing showing an example of the state of the fuel cut, FC elapsed crank counter Cfc, etc. when a fuel cut is executed again while fuel injection is being executed after returning from a fuel cut, and the fuel cut is returned from the fuel cut again. It is a chart. It is a flow chart which shows an example of fuel injection control after recovery from fuel cut of a modification. The state of the fuel cut, FC elapsed crank counter Cfc, etc. 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 recovery from the fuel cut. It is a timing chart which shows an example.

Next, a mode for carrying out the present invention will be described using examples.

FIG. 1 is a block diagram schematically showing the structure of a hybrid vehicle 20 equipped with an engine device according to an embodiment of the present invention, and FIG. 2 is a block diagram schematically showing the structure of an engine 22 and a fuel supply device 60. It 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 a hybrid electronic control unit. (hereinafter referred to as "HVECU") 70. 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 diesel oil. As shown in FIG. 2, the engine 22 includes a port injection valve 125 that injects fuel into an intake port, and an in-cylinder injection valve 126 that injects fuel into a cylinder. The engine 22 has a port injection valve 125 and an in-cylinder injection valve 126, so that it can be operated in either a port injection mode or an in-cylinder injection mode. In the port injection mode, air purified by the air cleaner 122 is sucked in through the throttle valve 124, and fuel is injected from the port injection valve 125 to mix air and fuel. This air-fuel mixture is then sucked into the combustion chamber via the intake valve 128 and exploded and combusted by electric sparks from the ignition plug 130, converting the reciprocating motion of the piston 132 pushed down by the energy into rotational motion of the crankshaft 26. . In the in-cylinder injection mode, similar to the port injection mode, air is sucked into the combustion chamber, fuel is injected from the in-cylinder injection valve 126 during the intake stroke or after the compression stroke, and explosive combustion is caused by electric sparks from the spark plug 130. to obtain rotational motion 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 via a purification device 134 that has a purification catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). be done.

As shown in FIG. 2, the fuel supply device 60 is configured as a device that supplies 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 a port injection valve 125 is connected, and a low pressure A check valve 64 provided in the side flow path 63 and a high pressure side flow path to which the in-cylinder injection valve 126 is connected by pressurizing the fuel on the port injection valve 125 side than the check valve 64 in the low pressure side flow path 63. (second flow path) 66.

Feed pump 62 and check valve 64 are arranged within fuel tank 61 . The feed pump 62 is configured as an electric pump that operates upon receiving power 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. The valve closes when the fuel pressure is below the side fuel pressure.

The high-pressure fuel pump 65 is a pump that is driven by power from the engine 22 (rotation of the camshaft) and pressurizes the fuel in the low-pressure side flow path 63. The high-pressure fuel pump 65 has an electromagnetic valve 65a connected to its suction port to open and close when pressurizing fuel, and a solenoid valve 65a connected to its discharge port to prevent backflow of fuel and maintain fuel pressure in the high-pressure side passage 66. check valve 65b. This high-pressure fuel pump 65 sucks fuel from the feed pump 62 when the solenoid valve 65a is opened while the engine 22 is operating, and receives fuel from the engine 22 when the solenoid valve 65a is closed. Fuel compressed by an activated plunger (not shown) is intermittently fed into the high-pressure side flow path 66 via the check valve 65b, thereby pressurizing the fuel supplied to the high-pressure side flow path 66. Note that 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 in accordance with the rotation of the engine 22 (rotation of the camshaft).

The engine 22 and the fuel supply device 60 are operationally 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, in addition to the CPU, a ROM for storing processing programs, a RAM for temporarily storing data, an input/output port, and a communication port. .

Signals from various sensors necessary to control the operation of the engine 22 and the fuel supply device 60 are input to the engine ECU 24 via input ports. 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. Another example is 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. Furthermore, the throttle opening TH from a throttle valve position sensor 146 that detects the position of the throttle valve 124, the intake air amount Qa from an air flow meter 148 attached to the intake pipe, and the temperature sensor 149 attached to the intake pipe Intake 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 cited. In addition, the rotation speed Nfp of the feed pump 62 is detected from the rotation speed sensor 62a attached to the feed pump 62 of the fuel supply device 60, and the port is detected from the fuel pressure sensor 68 attached near 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 cylinder injection valve 126 from the fuel pressure sensor 69 attached near the 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 outputted from the engine ECU 24 via an output port. 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 that adjusts the position of the throttle valve 124, and a drive signal integrated with the igniter. ignition coil 138. Further, a drive control signal to the feed pump 62 and a drive control signal to the electromagnetic valve 65a of the high-pressure fuel pump 65 can also be mentioned.

Engine ECU 24 is connected to 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. The engine ECU 24 also determines the volumetric efficiency (the volume of air actually taken in in one cycle relative to the stroke volume per cycle of the engine 22) based on the intake air amount Qa from the air flow meter 148 and the rotational speed Ne of the engine 22. (ratio of) KL is calculated.

As shown in FIG. 1, the planetary gear 30 is configured as a single pinion type planetary gear mechanism. The sun gear of the planetary gear 30 is connected to the rotor of the motor MG1. A drive shaft 36 connected to drive wheels 39a and 39b via a differential gear 38 is connected to the ring gear of the planetary gear 30. A 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, for example, as a synchronous generator motor, and has a rotor connected to the sun gear of the planetary gear 30, as described above. The motor MG2 is configured as, for example, a synchronous generator motor, and has a rotor connected to the drive shaft 36. Inverters 41 and 42 are connected to motors MG1 and MG2 as well as to battery 50 via power line 54. The motors MG1 and MG2 are rotationally driven by a motor electronic control unit (hereinafter referred to as "motor ECU") 40 that controls switching of a plurality of switching elements (not shown) of inverters 41 and 42.

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

The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel hydride secondary battery, and is connected to the inverters 41 and 42 via a power line 54. This 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, in addition to the CPU, a ROM for storing processing programs, a RAM for temporarily storing data, an input/output port, and a communication port. . Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via an 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 installed at the output terminal of the battery 50, and the battery 50. For example, the battery temperature Tb from the temperature sensor 51c attached to the battery temperature Tb can be mentioned. Battery ECU 52 is connected to HVECU 70 via a communication port. The battery ECU 52 calculates the storage percentage SOC based on the integrated value of the battery current Ib from the current sensor 51b. The power 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, in addition to the CPU, a ROM for storing processing programs, a RAM for temporarily storing data, an input/output port, and a communication port. Signals from various sensors are input to the HVECU 70 via input ports. Examples of signals input to the HVECU 70 include an ignition signal from an ignition switch 80 and a shift position SP from a shift position sensor 82 that detects the operating position of the shift lever 81. Further, the accelerator opening degree Acc from the accelerator pedal position sensor 84 which detects the amount of depression of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 which detects the amount of depression of the brake pedal 85, and the brake pedal position BP from the vehicle speed sensor 88. The vehicle speed V and the outside air temperature Tout from the outside air temperature sensor 89 can also be cited. As described above, the HVECU 70 is connected to the engine ECU 24, motor ECU 40, and battery ECU 52 via the communication port.

In the hybrid vehicle 20 of the embodiment configured in this manner, 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. Then, the engine 22 and motors MG1 and MG2 are operated and controlled. There are the following modes (1) to (3) as operating modes for the engine 22 and motors MG1 and MG2.
(1) Torque conversion operation mode: The operation of the engine 22 is controlled so that the power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is transferred to the planetary gear 30 and motors MG1 and MG2. (2) Charging and discharging operation mode: the sum of the required power and the electric power required for charging and discharging the battery 50. The operation of the engine 22 is controlled so that the engine 22 outputs power commensurate to (3) Motor operation mode: Operation of the engine 22 is stopped and the required power is output to the drive shaft 36. A mode for driving and controlling motor MG2 so that the output is output.

In the hybrid vehicle 20 of the embodiment, the engine ECU 24 controls intake air amount, fuel injection, and the feed pump 62 and high-pressure fuel pump 65 of the fuel supply device 60 when operating the engine 22.

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 TH becomes the target throttle opening TH*.

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

In controlling the feed pump 62, first, the feed pump is controlled based on the target fuel pressure Pfp* of the fuel supplied to the port injection valve 125 and the target injection amount Qfp*, Qfd* of the port injection valve 125 or the in-cylinder injection valve 126. 62 target discharge amount Qpp* 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 after a predetermined time T1 has elapsed, 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 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 controlling 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 more than ten MPa is used. In the embodiment, the target discharge amount Qpd* is set to increase as the target fuel pressure Pfd* becomes higher, and to increase as the target injection amount Qfd* increases. When the target discharge amount Qpd* is thus set, 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 according to the embodiment configured as described above, particularly the fuel injection control after recovery from fuel cut, will be described. FIG. 3 is a flowchart showing an example of fuel injection control after recovery from fuel cut, which is executed by the engine ECU 24 of the embodiment. This process is executed upon recovery from fuel cut.

When the fuel injection control after recovery from 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 from the fuel cut, and after the return from the fuel cut. It is reset to the value 0 when ending fuel injection control. The predetermined rotation angle may basically be any number of times, but it is preferably an angle for each combustion, an angle that is an integral multiple of the combustion, or an angle for each cycle. 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-stroke 8-cylinder engine, 90 degrees, 180 degrees, 360 degrees, 720 degrees, etc. are suitable. This is because the amount of heat removed from the valves and the inside of the cylinder is proportional to the number of air passages experienced during the fuel cut. Since the number of intakes during fuel cut in a certain cylinder is completely proportional to the crank angle integrated value, the predetermined rotation angle (integrated) during fuel cut is used instead of the fuel cut time. In the following embodiment, the engine 22 is a 4-stroke, 4-cylinder engine, and 180 degrees is used as the predetermined rotation angle so that the value of the FC plan rank counter Cfc corresponds to the number of combustions if fuel is injected. As the temperature Tw of the cooling water of the engine 22, the temperature detected by the temperature sensor 142 was input. 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 rotational speed Ne of the engine 22. Since it is the ratio of the volume of air actually taken in in one cycle to the stroke volume per cycle, it is the same as the load of the engine 22.

Next, a provisional direct injection continuation number Ntmp is set based on the inputted FC elapsed crank counter Cfc, engine 22 cooling water temperature Tw, and volumetric efficiency KL (step S110), and the provisional direct injection continuation number Ntmp and the remaining number Nd are set. The larger one of these is set as the direct injection continuation number Nfc (step S120). The number of continuous direct injections Nfc is the number of times fuel is injected in the direct injection mode after recovery from fuel cut, and when the remaining number of times Nd is an initial value of 0, a temporary number of continuous direct injections Ntmp is set. Therefore, the number of continuous direct injections 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 number of continuous direct injections Nfc is determined in advance through experiments, etc., and a map for setting the number of continuous direct injections is created. When the FC elapsed crank counter Cfc, the engine 22 cooling water temperature Tw, and the volumetric efficiency KL are given, the corresponding direct injection continuation number Nfc is derived from the map, and this is calculated as the temporary direct injection continuation number Ntmp. It was 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 counting up of the number of injections N after recovery is started (step S140). The number of injections after recovery N is the number of fuel injections after recovery from fuel cut, and is counted up from an initial value of 0 every time fuel injection is performed.

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

When it is determined in step S210 that the number of post-return injections N has reached the number of continuous direct injections Nfc, the execution injection mode is set to the normal setting, which sets the execution injection mode to the port injection mode or the in-cylinder injection mode based on the operating state of the engine 22, etc. (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 number of injections after recovery N are reset to the initial value 0 (step S250), and this control is ended. In this way, combustion in the engine 22 can be made more stable by continuing in-cylinder injection until the number of fuel injections (number of injections after recovery N) reaches the number of continuous direct injections Nfc after recovery from fuel cut. This makes it possible to prevent engine stalls from occurring.

When it is determined in step S150 that fuel cut is being performed, a value obtained by subtracting the number of post-return injections N from the number of continuous direct injections Nfc is calculated as the remaining number of times Nd (step S240). Then, the FC elapsed crank counter Cfc and the number of injections after recovery N are reset to the initial value 0 (step S250), and this control is ended. 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 remaining number Nd is set as the direct injection continuation number Nfc. Now, let us consider a case where this control is started upon recovery from a relatively long fuel cut, the fuel cut is performed again shortly after recovery, and the fuel cut returns again in a short time. In this case, a relatively large direct injection continuation number Nfc is set due to a relatively long fuel cut, and another fuel cut is performed within a short time after recovery, resulting in a small return from a relatively large direct injection continuation number Nfc. A relatively large residual number Nd is calculated by subtracting the number N of post-injections. On the other hand, since the second fuel cut returns 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 temporary direct injection continuation number Ntmp, which has a small value, and the remaining number Nd, which has a large value, are compared in magnitude, so the direct injection continuation number Nfc is set to the remaining number Nd, and the remaining number Nd is set as the direct injection continuation number Nfc. At the time of return, the in-cylinder injection mode will continue until fuel is injected the remaining number of times Nd. In other words, the remaining number of injections Nd, which is the number of injections remaining when continuing in-cylinder injection after returning from a relatively long fuel cut, is calculated, and the remaining number of injections when continuing in-cylinder injection after returning from a short-term fuel cut is calculated. Injection is continued the remaining number of times Nd. If the second fuel cut is carried out for a relatively long time, a relatively large provisional direct injection continuation number Ntmp is set, so the provisional direct injection continuation number Ntmp becomes greater than the remaining number Nd, and the direct injection continuation number Nfc is set as From these facts, the remaining number of times Nd is the direct injection continuation after returning from a fuel cut when another fuel cut is performed while executing fuel injection control after returning from a fuel cut. 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 post-return injections N from the number of continuous direct injections Nfc is calculated as the remaining number of times Nd (step S170). Next, the remaining number of times Nd is multiplied by the correction coefficient kf to calculate the number of continuous direct injections Nfc (step S180), and the number of continuous return degrees N is reset to the value 0, and at the same time, the count of the number of times N of continuous return degrees is started. (Step S190), and waits for the engine 22 to return from intermittent stop (Step S200). After the engine 22 is restored from the intermittent stop, a process of waiting for the number N of continuous return degrees in steps S150 to S210 to reach the number Nfc of continuous direct injection is executed. At this time, in-cylinder injection is continued for the newly set number of continuations of direct injection Nfc (the number of times obtained by multiplying the remaining number of times Nd by the correction coefficient kf). The temperature of the intake valve 126 rises due to in-cylinder injection and combustion after recovery from fuel cut, but the heat of the intake valve 126 escapes due to intermittent engine stoppage, so the effect of N in-cylinder injections increases. is decreasing. Therefore, the number of continuous direct injections Nfc after the engine 22 returns from intermittent stop must be made slightly larger than 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, FC elapsed crank counter Cfc, and post-recovery injection when neither the fuel cut again nor the engine 22 is stopped intermittently while executing the fuel injection control after returning from the fuel cut. 3 is a timing chart showing an example of a state in which in-cylinder injection is continued for a number of times N. During fuel cut (ON), the FC elapsed crank counter Cfc increases in accordance with the cumulative rotational speed of the crankshaft 26. At time T11 when the fuel cut is restored (OFF), the in-cylinder injection mode is set to the execution injection mode (ON), and the direct injection continuation number Nfc is set. Then, each time fuel is injected into the cylinder, the number of return degree injections N is counted up. At 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 set to the engine The normal setting is that the in-cylinder injection mode or the port injection mode is set depending on the operating state of the engine 22 and the like. In this way, combustion in the engine 22 can be made more stable by continuing in-cylinder injection until the number of fuel injections (number of injections after recovery N) reaches the number of continuous direct injections Nfc after recovery from fuel cut. This makes it possible to prevent engine stalls from occurring.

FIG. 5 shows the fuel cut, the FC elapsed crank counter Cfc, and the FC elapsed crank counter Cfc when the fuel cut is executed again while the fuel injection control is being executed after the return from the fuel cut, and after the return from the fuel cut. 5 is a timing chart showing an example of the number of injections N and the continuation of in-cylinder injection. At time T21 when the fuel is restored 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 fuel is injected into the cylinder, the number of return degree injections N is counted up. At time T22 when the fuel cut is started again before the number N of return degree injections reaches the number Nfc of continuous direct injection, the remaining number Nd is calculated by subtracting the number N of return degree injections from the number Nfc of continuous direct injections. Further, the return degree injection number N and the FC elapsed crank counter Cfc are reset, and the in-cylinder injection mode is canceled (turned OFF). Thereafter, during the fuel cut, the FC elapsed crank counter Cfc increases in accordance with the rotation of the crankshaft 26. At time T32 after recovery 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, the remaining number of times Nd functions as a lower limit guard, so in the case of a short fuel cut, the remaining number of times Nd is set to the number of continuous direct injection times Nfc. Then, each time fuel is injected into the cylinder, the number of return degree injections N is counted up. At 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 installed in the hybrid vehicle 20 of the embodiment described above, when returning from a fuel cut, the FC elapsed crank counter Cfc, which counts up every time the crankshaft 26 rotates by a predetermined rotation angle during the fuel cut, and the engine 22 The number of continuous direct injections Nfc is set based on the coolant temperature Tw and the load of the engine 22 (volume efficiency KL), and the direct injection mode is continued until the number of injections N after recovery reaches the number of continuous direct injections Nfc. The engine 22 is controlled so that in-cylinder injection is performed. Thereby, combustion after recovery from fuel cut can be made more stable, and occurrence of engine stall can be suppressed.

In the engine device installed in the hybrid vehicle 20 of the embodiment, when another fuel cut is performed while executing fuel injection control after recovery from a fuel cut, post-recovery injection is performed from the direct injection continuation number Nfc. The remaining number of times Nd is calculated by subtracting the number of times N, and the remaining number of times Nd is used as a lower limit guard when setting the number of continuous direct injections Nfc after recovery from another fuel cut. As a result, the number of times in-cylinder injection is continued after recovery from another fuel cut can be made more appropriate, and combustion after recovery from another fuel cut can be made more stable. .

In the engine device installed in the hybrid vehicle 20 of the embodiment, when the engine 22 is intermittently stopped while executing fuel injection control after recovery from a fuel cut, the number of injections after recovery Nfc is changed from the number of continuous direct injections Nfc. is calculated as the remaining number of times Nd, and the number of continuous direct injections Nfc is calculated by multiplying the remaining number of times Nd by a correction coefficient kf. Then, the number of return degree continuations N is reset to the value 0, and counting of the reset number of return degree continuations N is started, and the number of return degree continuations N that is reset after the engine 22 returns from the intermittent stop is newly set. In-cylinder injection is continued in the in-cylinder injection mode for the direct injection continuation number Nfc. Thereby, it is possible to more appropriately deal with the case where the engine 22 is intermittently stopped while in-cylinder injection is being continued after recovery from fuel cut.

In the engine device installed in the hybrid vehicle 20 of the example, the number of continuous direct injections Nfc was set based on the volumetric efficiency KL at the time of recovery from a fuel cut. However, 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 recovery from fuel cut, direct injection is performed based on the volumetric efficiency after the change. The number of continuations Nfc may be reset. In this case, the fuel injection control after the return from the fuel cut shown in FIG. 6 may be executed instead of the fuel injection control after the return from the fuel cut shown in FIG. The fuel injection control after the return from the fuel cut shown in FIG. 6 is the fuel injection control after the return from the fuel cut shown in FIG. , the processing from steps S100 to S130, and the processing from steps S160 to S200 are omitted from illustration.

In the fuel injection control after the return from the fuel cut shown in FIG. The amount of change ΔKL from the time is calculated (step S142), and it is determined whether the absolute value of the amount of change ΔKL is greater than or equal to 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 too large to be ignored, and uses a value such as 30% or 40% of the maximum value of the volumetric efficiency KL. 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 advances to step S150. On the other hand, when it is determined that the absolute value of the change amount ΔKL is greater than or equal to the threshold value KLref, the temporary direct injection continuation number Ntmp is reset based on the FC elapsed crank counter Cfc, the engine 22 cooling water temperature Tw, and the volumetric efficiency KL. (Step S146), the larger of the temporary direct injection continuation number Ntmp and the remaining 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 while executing fuel injection control after returning from the fuel cut. , is a timing chart showing an example of the number of injections N after return, and the continuation of in-cylinder injection. In the figure, the broken line after time T33 indicates the state when there is no significant change in the volumetric efficiency KL. At time T31 when the fuel is restored 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 fuel is injected into the cylinder, the number of return degree injections N is counted up. When the accelerator pedal 83 is depressed at time T32 and the volumetric efficiency KL changes significantly, the direct injection continuation number Nfc is reset. At time T33 when the return degree injection number N reaches the reset direct injection continuation number Nfc, the return degree injection number N and the FC elapsed crank counter Cfc are reset, and the in-cylinder injection mode is canceled (OFF). In addition, if there is no significant change in the volumetric efficiency KL, at time T34 when the return degree injection number N reaches the direct injection continuation number Nfc set at the time of recovery from fuel cut, the return degree injection number N and FC elapsed crank Counter Cfc is reset and 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 while executing fuel injection control after returning from a fuel cut, the direct injection continuation number Nfc is changed again. By setting this, it is possible to cope with a large change in the 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 power may be used, and a capacitor or the like may be used.

Although the hybrid vehicle 20 of the embodiment includes an engine ECU 24, a motor ECU 40, a battery ECU 52, and an HVECU 70, at least two of these 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. The configuration is such that the battery 50 is connected via a power line. However, it may be configured as a so-called one-motor hybrid vehicle, a so-called series hybrid vehicle, or a so-called normal gasoline vehicle.

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

The correspondence relationship between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem is that the example implements the invention described in the column of means for solving the problem. Since this is an example for specifically explaining a form for solving the problem, it is not intended to limit the elements of the invention described in the column of means for solving the problems. In other words, the interpretation of the invention described in the column of means for solving the problem should be based on the description in that column, and the examples are based on the description of the invention described in the column of means for solving the problem. This is just one specific example.

Although the embodiments of the present invention have been described above using examples, the present invention is not limited to these examples in any way, and may be modified in various forms without departing from the gist of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing industry of an engine device, etc.

20 hybrid vehicle, 22 engine, 24 engine ECU, 26 crankshaft, 28 damper, 30 planetary gear, 36 drive shaft, 38 differential gear, 39a, 39b drive wheel, 40 motor ECU, 41, 42 inverter, 43, 44 rotational 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 Rotational speed sensor, 63 Low pressure side flow path, 64 Check valve, 65 High pressure fuel pump, 65a Solenoid 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 purifier, 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 an intake port and an in-cylinder injection valve that injects fuel into a cylinder;
a control device that controls the engine;
An in-vehicle engine device comprising:
The control device includes:
When returning from a fuel cut, the number of continuous direct injections is set based on a crank rotation counter that counts up every time the crankshaft rotates a predetermined rotation angle during the fuel cut, the cooling water temperature, and the engine load, and the direct injection continues. Executing return control to control the engine so that in-cylinder injection is performed continuously for a number of times;
When a fuel cut is executed again during execution of the return control, when returning from the fuel cut again, the number of direct injection continuations set at the time of return from the previous fuel cut is increased during the return control. The greater of the remaining number after subtracting the number of in-cylinder injections and the number of continuous direct injections set based on the crank rotation counter that counts up during the fuel cut again, the cooling water temperature, and the engine load. executing the return control using the new direct injection continuation number as the new number of direct injection continuations;
An engine device characterized by:

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