Engine device

Abstract

To suppress unnecessary fuel injection and ignition in starting an engine in which fuel injection and ignition are performed in a cylinder which reaches a compression top dead center first.SOLUTION: An engine device includes: an engine having a cylinder injection valve; a motor; a clutch connected to a crankshaft of the engine and the motor; a hydraulic control device having a hydraulic circuit to the clutch and controlling hydraulic pressure of the hydraulic circuit: and a control device controlling the engine, the motor, and the hydraulic control device. The control device prohibits fuel injection and ignition in the engine until half-engagement of the clutch is started.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an engine device, and more particularly to an engine device including an engine having an in-cylinder injection valve and a motor connected to an output shaft of the engine via a clutch.

Background Art

[0002] Conventionally, as this type of engine device, a hybrid vehicle including an engine, a motor connected to an output shaft of the engine via a clutch, and an automatic transmission connected to a rotating shaft of the motor and an axle has been proposed (see, for example, Patent Document 1). In this hybrid vehicle, when the vehicle is being driven by the motor with the clutch disengaged, the engine is started while controlling the clutch toward engagement.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the engine device mounted on the above-described hybrid vehicle, when starting the engine by performing fuel injection and ignition in the cylinder that first reaches top dead center of compression, unnecessary fuel injection and ignition may occur, and in some cases, the engine may rotate in reverse. When cranking the engine with the motor, it is necessary to semi-engage the clutch. When semi-engaging the clutch, first, fast filling is performed on the hydraulic circuit to the clutch, and after a slight constant pressure standby, semi-engagement is started. If the hydraulic pressure becomes higher than the target hydraulic pressure during fast filling, an unexpected semi-engaged state of the clutch will occur, and the engine will be rotated. Since the torque transmitted by this rotation is not as large as the torque during cranking, it is difficult to start the engine even if fuel injection and ignition are performed, resulting in unnecessary fuel injection and ignition. Also, depending on the engine rotation backlash and ignition timing, there may be cases where the engine is rotated in reverse due to unnecessary explosion combustion.

[0005] The engine device of the present invention mainly aims to suppress unnecessary fuel injection and ignition during engine starting where fuel injection and ignition are performed in the cylinder that first reaches top dead center of compression.

Means for Solving the Problem

[0006] The engine device of the present invention has adopted the following means to achieve the above main object.

[0007] The engine device of the present invention is an engine device comprising an engine having an in-cylinder injection valve, a motor, a clutch connected to the crankshaft of the engine and the motor, a hydraulic control device for controlling the hydraulic pressure of the hydraulic circuit to the clutch, and a control device for controlling the engine, the motor, and the hydraulic control device. When starting the engine, the control device performs fast filling on the hydraulic circuit for the clutch, waits at a constant pressure, then semi-engages the clutch, and while the engine is cranked by the motor, fuel injection and ignition are performed on the cylinder that first reaches the compression top dead center in the engine, and the engine, the motor, and the hydraulic control device are controlled so that the engine is started. The control device prohibits fuel injection and ignition in the engine until the semi-engagement of the clutch is started. It is characterized by this.

[0008] The engine device of the present invention includes an engine having an in-cylinder injection valve, a motor connected to the output shaft of the engine via a clutch, and a control device that controls the engine, the motor, and the clutch. When starting the engine, the control device performs fast filling on the hydraulic circuit for the clutch, waits at a constant pressure, then semi-engages the clutch, and while the engine is cranked by the motor, fuel injection and ignition are performed on the cylinder that first reaches the compression top dead center in the engine, and the engine, the motor, and the hydraulic control device are controlled so that the engine is started. The stop crank angle of the cylinder that first reaches the compression top dead center is within 180 degrees before the compression top dead center (TDC) for a 4-cylinder engine and within 120 degrees before the compression top dead center for a 6-cylinder engine. Therefore, in order to perform fuel injection and ignition (first explosion) in the cylinder that first reaches the compression top dead center, fuel injection is performed during the compression stroke from the stop crank angle to the compression top dead center, and ignition is performed near the compression top dead center. When starting the engine in this way, the control device prohibits fuel injection and ignition in the engine until the semi-engagement of the clutch is started. Therefore, when the hydraulic pressure becomes higher than the target hydraulic pressure during fast filling, an unexpected semi-engaged state of the clutch occurs, and even if the engine rotates, fuel injection and ignition are not performed. As a result, unnecessary fuel injection and ignition during fast filling can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] Next, embodiments for carrying out the present invention will be described using examples.

Example

[0011] 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. FIG. 2 is a configuration diagram showing an outline of the configuration of the engine 22 mounted on the hybrid vehicle 20. As shown in FIG. 1, the hybrid vehicle 20 of the embodiment includes an engine 22, a motor 30, an inverter 32, a clutch K0, a hydraulic control device 36, an automatic transmission 40, a high-voltage battery 60, a low-voltage battery 62, a DC / DC converter 64, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0012] The engine 22 is configured as a six-cylinder internal combustion engine that outputs power through four strokes of intake, compression, expansion (explosive combustion), and exhaust using fuel such as gasoline or light oil. As shown in FIG. 2, the engine 22 has a port injection valve 126 that injects fuel into the intake port and an in-cylinder injection valve 127 that injects fuel into the cylinder. By having the port injection valve 126 and the in-cylinder injection valve 127, the engine 22 can be operated in any of a port injection mode, an in-cylinder injection mode, and a common injection mode. In the port injection mode, air cleaned by the air cleaner 122 is inhaled into the intake pipe 123, passed through the throttle valve 124 and the surge tank 125, and fuel is injected from the port injection valve 126 on the downstream side of the surge tank 125 in the intake pipe 123 to mix the air and fuel. Then, this air-fuel mixture is inhaled into the combustion chamber 129 through the intake valve 128 and explosively combusted by an electric spark from the spark plug 130, converting the reciprocating motion of the piston 132 pushed down by the energy in the cylinder bore into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is inhaled into the combustion chamber 129 in the same manner as in the port injection mode, fuel is injected from the in-cylinder injection valve 127 during the intake stroke and the compression stroke, and explosively combusted by an electric spark from the spark plug 130 to obtain the rotational motion of the crankshaft 23. In the common injection mode, fuel is injected from the port injection valve 126 when air is inhaled into the combustion chamber 129, and fuel is injected from the in-cylinder injection valve 127 during the intake stroke and the compression stroke, and explosively combusted by an electric spark from the spark plug 130 to obtain the rotational motion of the crankshaft 23. These injection modes are switched based on the operating state of the engine 22. The exhaust discharged from the combustion chamber 129 to the exhaust pipe 134 through the exhaust valve 133 is discharged to the outside air through the purification device 135 and the PM filter 136. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) in the exhaust. The PM filter 136 is formed as a porous filter made of ceramics, stainless steel, etc., and collects particulate matter (PM) such as soot in the exhaust.Note that instead of the PM filter 136, a four-way catalyst that combines the purification function of a three-way catalyst and the collection function for particulate matter may be used.

[0013] The engine 22 is under operation control by the engine ECU 24. The engine ECU 24 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, input / output ports, and communication ports, although not shown in the figure. Signals from various sensors necessary for controlling the operation of the engine 22 are input to the engine ECU 24 via the input ports. Examples of the signals input to the engine ECU 24 include the crank angle θcr from the crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and the coolant temperature Tw from the water temperature sensor 142 that detects the temperature of the coolant of the engine 22. Also included are the cam angles θci and θco from the cam position sensor 144 that detects the rotational positions of the intake camshaft that opens and closes the intake valve 128 and the exhaust camshaft that opens and closes the exhaust valve 133. Further examples include the throttle opening TH from the throttle valve position sensor 124a that detects the position of the throttle valve 124, the intake air quantity Qa from the air flow meter 123a attached upstream of the throttle valve 124 in the intake pipe 123, the intake air temperature Ta from the temperature sensor 123t attached upstream of the throttle valve 124 in the intake pipe 123, and the surge pressure Ps from the pressure sensor 125a attached to the surge tank 125. Also included are the front air-fuel ratio AF1 from the front air-fuel ratio sensor 137 attached upstream of the purification device 135 in the exhaust pipe 134, the rear air-fuel ratio AF2 from the rear air-fuel ratio sensor 138 attached between the purification device 135 and the PM filter 136 in the exhaust pipe 134, and the differential pressure ΔP from the differential pressure sensor 136a that detects the differential pressure (the differential pressure between the upstream side and the downstream side) before and after the PM filter 136. As is well known, the crank position sensor 140 is composed of a timing rotor having 34 protrusions formed by deleting two consecutive protrusions as missing teeth from 36 protrusions at 10-degree intervals on the outer circumference, and an electromagnetic pickup that detects the passage of the protrusions as the timing rotor rotates.

[0014] From the engine ECU 24, various control signals for controlling the operation of the engine 22 are output via the output ports. Examples of the signals output from the engine ECU 24 include a control signal to the throttle valve 124, a control signal to the port injection valve 126, a control signal to the in-cylinder injection valve 127, and a control signal to the ignition plug 130.

[0015] The engine ECU 24 is connected to the HV ECU 70 via a communication port. The engine ECU 24 calculates the engine speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140. Further, the engine ECU 24 calculates the load factor KL (the ratio of the volume of air actually inhaled in one cycle to the stroke volume per cycle of the engine 22) based on the intake air amount Qa from the air flow meter 123a and the engine speed Ne of the engine 22. Furthermore, the engine ECU 24 calculates the PM deposition amount Qpm as the deposition amount of particulate matter deposited on the PM filter 136 based on the differential pressure ΔP from the differential pressure sensor 136a, or calculates the filter temperature Tf as the temperature of the PM filter 136 based on the engine speed Ne and the load factor KL of the engine 22.

[0016] As shown in FIG. 1, a starter motor 25 for cranking the engine 22 and an alternator 26 for generating electricity using the power from the engine 22 are connected to the crankshaft 23 of the engine 22. The starter motor 25 and the alternator 26 are connected to the low-voltage side power line 63 together with the low-voltage battery 62 and are controlled by the HV ECU 70.

[0017] The motor 30 is configured as a synchronous generator motor, and includes a rotor in which permanent magnets are embedded in a rotor core, and a stator in which three-phase coils are wound around a stator core. A rotating shaft 31, to which the rotor of this motor 30 is fixed, is connected to the crankshaft 23 of the engine 22 via a clutch K0 and is also connected to the input shaft 41 of the automatic transmission 45. The inverter 32 is used to drive the motor 30 and is connected to the high-voltage side power line 61. The motor 30 is rotationally driven by switching control of a plurality of switching elements of the inverter 32 by a motor electronic control unit (hereinafter referred to as "motor ECU") 34.

[0018] Although not shown, the motor ECU 34 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the motor ECU 34 via the input ports. Examples of the signals input to the motor ECU 34 include the rotational position θm from a rotational position sensor 30a that detects the rotational position of the rotor (rotating shaft 31) of the motor 30, and the phase currents Iu and Iv from current sensors that detect the phase currents of each phase of the motor 30. Control signals to the inverter 32 and the like are output from the motor ECU 34 via the output ports. The motor ECU 34 is connected to the HVECU 70 via a communication port. The motor ECU 34 calculates the rotational speed Nm of the motor 30 based on the rotational position θm of the rotor (rotating shaft 31) of the motor 30 from the rotational position sensor 30a.

[0019] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and is driven by a hydraulic control device 36 to connect and disconnect the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30. The hydraulic control device 36 has a hydraulic circuit 37 for the clutch K0, and adjusts the hydraulic pressure of the hydraulic circuit 37 to set the clutch K0 in a semi-engaged state (slip engagement state), a fully engaged state, or a released state (engagement released state). Note that the hydraulic control device 36 is controlled by the HVECU 70.

[0020] The automatic transmission 40 includes a torque converter 43 and an automatic transmission 45 with, for example, six forward speeds. The torque converter 43 is configured as a general fluid transmission device, and transmits the power of the input shaft 41 connected to the rotating shaft 31 of the motor 30 to the input shaft of the automatic transmission 45, i.e., the transmission input shaft 44, either by amplifying the torque or transmitting it as it is without torque amplification. The automatic transmission 45 includes a transmission input shaft 44, an output shaft 42 connected to the drive wheels 49 via a differential gear 48, a plurality of planetary gears, and a plurality of hydraulically driven friction engagement elements (clutches, brakes). Each of the plurality of friction engagement elements has a hydraulic servo composed of a piston, a plurality of friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, and the like. The automatic transmission 45 forms forward and reverse gears from the first speed to the sixth speed by engaging and disengaging the plurality of friction engagement elements, and transmits power between the transmission input shaft 44 and the output shaft 42. The clutch K0 and the automatic transmission 45 are supplied with hydraulic oil pressure regulated from a mechanical oil pump or an electric oil pump by a hydraulic control device (not shown). The hydraulic control device includes a valve body in which a plurality of oil passages are formed, a plurality of regulator valves, a plurality of linear solenoid valves, and the like. This hydraulic control device is controlled by the HVECU 70. Note that the hydraulic control device 36 that drives the clutch K0 and the hydraulic control device that drives the automatic transmission 40 may be integrated or separate.

[0021] The high-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery with a rated voltage of about several hundred volts, and is connected to the high-voltage side power line 61 together with the inverter 32. The low-voltage battery 62 is configured as, for example, a lead-acid battery with a rated voltage of about 12V or 14V, and is connected to the low-voltage side power line 63 together with the starter motor 25 and the alternator 26. The DC / DC converter 64 is connected to the high-voltage side power line 61 and the low-voltage side power line 63. This DC / DC converter 64 supplies the power of the high-voltage side power line 61 to the low-voltage side power line 63 with voltage step-down.

[0022] The HVECU 70 includes a microcomputer (not shown) having a CPU, a ROM, a RAM, a flash memory, input / output ports, and communication ports. Signals from various sensors are input to the HVECU 70 via the input ports. Examples of the signals input to the HVECU 70 include the rotational speed Nin from the rotational speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotational speed Nmi from the rotational speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotational speed Nout from the rotational speed sensor 42a attached to the output shaft 42 of the automatic transmission 40. Also included are the voltage Vbh of the high-voltage battery 60 from the voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from the current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from the voltage sensor attached between the terminals of the low-voltage battery 62. Further examples are the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, 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 V from the vehicle speed sensor 87.

[0023] Various control signals are output from the HVECU 70 via the output ports. Examples of the signals output from the HVECU 70 include the control signal to the starter motor 25 and the control signal to the alternator 26. Also included are the control signal to the hydraulic control device 36 that drives the clutch K0, the control signal to the hydraulic control device that drives the automatic transmission 40, and the control signal to the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 and the motor ECU 34 via the communication ports. The HVECU 70 calculates the gear ratio Gt of the automatic transmission 40 by dividing the rotational speed Nin of the input shaft 41 of the automatic transmission 40 from the rotational speed sensor 41a by the rotational speed Nout of the output shaft 42 of the automatic transmission 40 from the rotational speed sensor 42a.

[0024] In the hybrid vehicle 20 of the embodiment configured in this way, the engine 22, the clutch K0, the motor 30, and the automatic transmission 40 are controlled so as to travel in a hybrid driving mode (HV driving mode) or an electric driving mode (EV driving mode) by the cooperative control of the HVECU 70, the engine ECU 24, and the motor ECU 34. Here, the HV driving mode is a mode in which the vehicle travels using the power of the engine 22 with the clutch K0 engaged, and the EV driving mode is a mode in which the vehicle travels without using the power of the engine 22 with the clutch K0 disengaged.

[0025] In the control of the automatic transmission 40 in the HV driving mode and the EV driving mode, the HVECU 70 first sets the target gear stage M* of the automatic transmission 45 based on the accelerator opening Acc and the vehicle speed V. Then, when the gear stage M of the automatic transmission 45 coincides with the target gear stage M*, the automatic transmission 45 is controlled so that the gear stage M is maintained. On the other hand, when the gear stage M is different from the target gear stage M*, the automatic transmission 45 is controlled so that the gear stage M coincides with the target gear stage M*.

[0026] In the control of the engine 22 and the motor 30 in the HV driving mode, the HVECU 70 first sets a required torque Tout* required for driving (required for the output shaft 42 of the automatic transmission 40) based on the accelerator opening Acc and the vehicle speed V. Subsequently, a value obtained by dividing the required torque Tout* of the output shaft 42 by the gear ratio Gt of the automatic transmission 40 is set as the required torque Tin* of the input shaft 41. When the required torque Tin* of the input shaft 41 is set in this way, the target torque Te* of the engine 22 and the torque command Tm* of the motor 30 are set so that the required torque Tin* is output to the input shaft 41. The target torque Te* of the engine 22 is transmitted to the engine ECU 24, and the torque command Tm* of the motor 30 is transmitted to the motor ECU 34. When receiving the target torque Te*, the engine ECU 24 performs operation control (such as intake air amount control, fuel injection control, ignition control, etc.) of the engine 22 so that the engine 22 is operated at the target torque Te*. When receiving the torque command Tm*, the motor ECU 34 performs switching control of a plurality of switching elements of the inverter 32 so that the motor 30 is driven by the torque command Tm*.

[0027] In the control of the motor 30 in the EV driving mode, the HVECU 70 sets the required torque Tin* of the input shaft 41 in the same manner as in the HV driving mode, sets the torque command Tm* of the motor 30 so that the required torque Tin* is output to the input shaft 41, and transmits it to the motor ECU 34. When receiving the torque command Tm*, the motor ECU 34 performs switching control of a plurality of switching elements of the inverter 32 so that the motor 30 is driven by the torque command Tm*.

[0028] In the embodiment, as the engine device, the engine 22, the clutch K0, the hydraulic control device 36, the motor 30, the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond.

[0029] Next, the operation of the hybrid vehicle 20 of the thus configured embodiment will be described, particularly the operation when starting the engine 22 while the engine 22 is operating intermittently. In the embodiment, when starting the engine 22 while it is operating intermittently, basically, the clutch K0 is semi-engaged (slip engaged) to output the target cranking torque Tcr* from the motor 30 to crank the engine 22, and the first fuel injection and ignition (first explosion) are performed in the cylinder that first reaches the compression top dead center (TDC: Top Dead Center). FIG. 3 is a flowchart showing an example of the start-up process executed by the engine ECU 24 and the HV ECU 70.

[0030] When the start-up process is executed, first, fuel injection and ignition are prohibited (step S100). The prohibition of fuel injection and ignition is performed, for example, by setting the value 1 to the fuel injection ignition permission flag F in the HV ECU 70. In the embodiment, the fuel injection ignition permission flag F is transmitted from the HV ECU 70 to the engine ECU 24, and the engine ECU 24 does not perform fuel injection and ignition when the transmitted fuel injection ignition permission flag F has the value 1, and can be executed by performing fuel injection and ignition when the fuel injection ignition permission flag F has the value 0.

[0031] Subsequently, fast filling of the hydraulic circuit 37 to the clutch K0 is performed (step S110), and constant pressure standby is executed (step S120). Fast filling is to pre-pack the hydraulic oil into the hydraulic circuit 37 to the clutch K0, a cylinder (not shown), etc. in order to quickly drive the clutch K0. In the embodiment, it is performed by increasing the target hydraulic pressure Poil* of the hydraulic circuit 37 to the clutch K0. Constant pressure standby is to wait with the hydraulic pressure of the hydraulic circuit 37 to the clutch K0 set to a hydraulic pressure at which no engaging force (frictional force) is generated in the clutch K0. In the embodiment, it is performed by setting the target hydraulic pressure Poil* slightly lower than that of the fast filling.

[0032] When reaching the constant-pressure standby state, the clutch K0 is semi-engaged (slip engaged) to output the target cranking torque Tcr* from the motor 30 to start cranking the engine 22 (step S130). At the same time, the fuel injection ignition permission flag F is set to the value 0 to release the prohibition of fuel injection and ignition (step S140). Since the fuel injection ignition permission flag F set to the value 0 is transmitted from the HVECU 70 to the engine ECU 24, fuel injection and ignition by the engine ECU 24 are thereby started. Cranking of the engine 22 is performed by transmitting a control signal from the HVECU 70 to the hydraulic control device 36 so that the clutch K0 is semi-engaged (slip engaged), and transmitting the torque of the sum of the required torque Tin* required for the input shaft 41 and the target cranking torque Tcr* to the motor ECU 34 as the torque command Tm* of the motor 30. The hydraulic control device 36 that has received the control signal adjusts the target oil pressure Poil* to a predetermined oil pressure so that the clutch K0 can transmit the target cranking torque Tcr* while slipping. The motor ECU 34 that has received the torque command Tm* performs switching control on the switching elements (not shown) of the inverter 32 so that the torque command Tm* is output from the motor 30. In the embodiment, the target cranking torque Tcr* is set based on the torque sufficient to cause the cylinder stopped in the compression stroke to exceed the compression top dead center, and based on the stopped crank angle θstop and the elapsed time since the engine 22 was stopped. The reason for being based on the stopped crank angle θstop is to consider the pressure in the cylinder stopped in the compression stroke, and the reason for being based on the elapsed time since the engine 22 was stopped is to consider that the pressure in the cylinder stopped in the compression stroke decreases over time.

[0033] Subsequently, the fuel injection amount Fi in the cylinder that first reaches top dead center of compression is set based on the elapsed time Tstop after the engine 22 is stopped, the stop crank angle θstop (position of the piston 132), and the intake manifold pressure (inmanipressure) Pin at the timing when the intake valve 128 closes (step S150). The reason for setting the fuel injection amount Fi based on the elapsed time Tstop after the engine 22 is stopped is that the amount of air in the cylinder that first reaches top dead center of compression decreases as the elapsed time Tstop after the engine 22 is stopped becomes longer. The reason for setting the fuel injection amount Fi based on the stop crank angle θstop (position of the piston 132) is that the closer the position of the piston 132 is to top dead center of compression, the higher the pressure in the cylinder becomes and the easier it is for air to escape from the piston rings. The reason for setting the fuel injection amount Fi based on the inmanipressure Pin is that the larger the inmanipressure Pin is, the more the amount of air in the cylinder becomes. In order to obtain good starting performance at the first explosion, as the fuel injection amount Fi for the cylinder that first reaches top dead center of compression, it is preferably set such that it decreases as the elapsed time Tstop after the engine 22 is stopped becomes longer, it decreases as the stop crank angle θstop (position of the piston 132) gets closer to top dead center of compression, and it increases as the inmanipressure Pin becomes larger.

[0034] In conjunction with the setting of the above fuel injection amount Fi, the ignition timing Ti is set based on the stop crank angle θstop, the target cranking torque Tcr*, and the rotational speed Nmg of the motor 30 (step S160). In the cylinder where fuel injection and ignition are first performed, the further the stop crank angle θstop is from its compression top dead center (larger as BTDC), the more the amount of air in the cylinder increases. When the amount of air in the cylinder is large, the shock at the time of the first explosion becomes large. Therefore, in order to reduce the shock, it is preferable to retard the ignition timing. Thus, in the embodiment, the ignition timing Ti is set so as to be retarded more as the stop crank angle θstop is further from the compression top dead center (larger as BTDC) within the range of the retard limit where ignition is possible. As described above, the target cranking torque Tcr* is set to be larger as the amount of air in the cylinder that first reaches the compression top dead center is larger. Therefore, in the embodiment, the ignition timing Ti is set so as to be retarded more as the target cranking torque Tcr* is larger within the range of the retard limit where ignition is possible. In order to quickly start the engine 22 and use the power from the engine 22 via the clutch K0 to travel, it is necessary to control the rotational speed Ne of the engine 22 to approximately match the rotational speed Nmg of the motor 30 and engage the clutch K0. When the rotational speed Nmg of the motor 30 is large, it takes time to make the rotational speed Ne immediately after starting the engine 22 approximately match the rotational speed Nmg of the motor 30. Therefore, it is preferable to increase the torque of the engine 22 even at the first explosion to increase the rotational speed Ne of the engine 22. Thus, in the embodiment, the ignition timing Ti is set so as to be advanced more as the rotational speed Nmg of the motor 30 is larger. From these, in the embodiment, the ignition timing Ti is determined in advance by experiments, analysis, machine learning, etc. based on the relationship between the stop crank angle θstop, the target cranking torque Tcr*, the rotational speed Nmg of the motor 30, and the ignition timing Ti, and stored as a map for setting the ignition timing for the first explosion. When the stop crank angle θstop, the target cranking torque Tcr*, and the rotational speed Nmg of the motor 30 are given, the corresponding ignition timing Ti is derived from the map and set.Note that, as a basic ignition timing, the ignition timing may be set by advancing or retarding the stop crank angle θstop, the target cranking torque Tcr*, and the rotation speed Nmg of the motor 30 with respect to a timing near top dead center of compression, for example, ATDC 5 (5 degrees after TDC).

[0035] When the fuel injection amount Fi and the ignition timing Ti are set in this way, fuel injection is performed by injecting from the in-cylinder injection valve 127 at the timing until reaching top dead center of compression with the set fuel injection amount Fi, and ignition is performed at the set ignition timing Ti (step S170).

[0036] FIG. 4 is an explanatory diagram showing the control phase of the clutch K0, the target oil pressure Poil* of the hydraulic circuit 37 to the clutch K0, the engine speed Ne of the engine 22, the start request, and the time change of the permission / non-permission of fuel injection and ignition at the start of the engine 22. At time T1 when the start request of the engine 22 becomes ON, the control phase of the clutch K0 becomes standby and the value 1 is set to the fuel injection ignition permission / non-permission flag F to prohibit fuel injection and ignition. After a slight time elapse from then, at time T2, the control phase of the clutch K0 becomes fast fill (denoted as "FF" in the figure), and a hydraulic pressure for fast fill (a hydraulic pressure slightly higher than the hydraulic pressure of the constant pressure standby after fast fill) is set to the target oil pressure Poil* of the hydraulic circuit 37. At this time, since the value 1 is set to the fuel injection ignition permission / non-permission flag F to prohibit fuel injection and ignition, even if the hydraulic pressure unexpectedly becomes higher than the target oil pressure Poil* and rotates the engine 22 during fast fill, fuel injection and ignition are not performed. Then, at time T3 when the control phase of the clutch K0 becomes constant pressure standby, a hydraulic pressure for constant pressure standby (a hydraulic pressure at which the engaging force (frictional force) does not act on the clutch K0) is set to the target oil pressure Poil* of the hydraulic circuit 37. Further thereafter, at time T4 when the control phase of the clutch K0 becomes semi-engagement (cranking), a hydraulic pressure for semi-engagement (slip engagement) (a hydraulic pressure at which the engaging force (frictional force) acts on the clutch K0) is set to the target oil pressure Poil* of the hydraulic circuit 37, and at the same time, the value 0 is set to the fuel injection ignition permission / non-permission flag F to release the prohibition of fuel injection and ignition. Then, fuel injection is performed until the compression top dead center of the cylinder that first reaches the compression top dead center, and ignition is performed at time T5 near the compression top dead center to cause the first explosion.

[0037] Subsequently, control is performed on the cylinder that reaches the compression top dead center after the second one (step S180), and this process ends. As the control for the cylinder that reaches the compression top dead center after the second time, the fuel injection amount Fi and the ignition timing Ti are set so that the rotational speed Ne of the engine 22 approaches the rotational speed Nmg of the motor 30, and the engine 22 is controlled so that the rotational speed Ne of the engine 22 synchronizes with the rotational speed Nmg of the motor 30 in a state where the half-engagement (slip engagement) of the clutch K0 is continued or in a state where the half-engagement (slip engagement) of the clutch K0 is released. When the rotational speed Ne of the engine 22 synchronizes with the rotational speed Nmg of the motor 30, the clutch K0 is fully engaged to end the starting process of the engine 22.

[0038] In the engine device mounted on the hybrid vehicle 20 of the embodiment described above, when starting the engine 22 that has been intermittently stopped, fast fill and constant pressure standby for the clutch K0 are performed with fuel injection and ignition prohibited, the clutch K0 is half-engaged (slip engaged), and cranking of the engine 22 by the motor 30 is started. At the same time, by releasing the prohibition of fuel injection and ignition, it is possible to suppress fuel injection and ignition from being performed even when the engine 22 rotates due to the hydraulic pressure unexpectedly becoming higher than the target hydraulic pressure Poil* during fast fill. As a result, it is possible to suppress unnecessary fuel injection and ignition in the starting of the engine 22 where fuel injection and ignition are performed in the cylinder that first reaches the compression top dead center.

[0039] In the engine device mounted on the hybrid vehicle 20 of the embodiment, when starting the engine 22 by starting the cranking of the engine 22 by outputting the target cranking torque Tcr* from the motor 30 with the clutch K0 semi-engaged (slip engaged), when performing fuel injection and ignition (first explosion) in the cylinder that first reaches top dead center of compression, the fuel injection amount Fi is set so that it decreases as the elapsed time Tstop since the engine 22 stopped becomes longer, so that it decreases as the stop crank angle θstop (position of the piston 132) gets closer to top dead center of compression, and so that it increases as the intake manifold pressure Pin becomes larger. Thereby, the fuel injection amount for the cylinder that first reaches top dead center of compression can be made more appropriate, and the starting performance of the engine 22 can be improved. Further, when starting the engine 22 and performing fuel injection and ignition (first explosion) in the cylinder that first reaches top dead center of compression, the ignition timing Ti is set so that it retards as the stop crank angle θstop is farther from top dead center of compression (larger as BTDC), so that it retards as the target cranking torque Tcr* becomes larger, and so that it advances as the rotational speed Nmg of the motor 30 becomes larger. Thereby, the engine 22 can be started quickly and the shock of the first explosion can be suppressed. As a result, it is possible to achieve both good starting performance of the engine 22 and suppression of the shock that may occur when starting the engine 22.

[0040] In the engine device mounted on the hybrid vehicle 20 of the embodiment, when fuel injection and ignition (initial explosion) are performed in the cylinder that first reaches top dead center of compression, the fuel injection amount Fi is set such that it decreases as the elapsed time Tstop since the engine 22 is stopped becomes longer, decreases as the stop crank angle θstop (the position of the piston 132) gets closer to top dead center of compression, and increases as the intake manifold pressure Pin becomes larger. However, when fuel injection and ignition (initial explosion) are performed in the cylinder that first reaches top dead center of compression, the fuel injection amount Fi may be set based on the elapsed time Tstop since the engine 22 is stopped and the stop crank angle θstop (the position of the piston 132), without relying on the intake manifold pressure Pin. In this case, the fuel injection amount Fi may be set using the solid line Fi(1) or the solid line Fi(2) with a relatively large value as the initial value for the intake manifold pressure Pin. Also, the fuel injection amount Fi may be set based on the elapsed time Tstop since the engine 22 is stopped and the intake manifold pressure Pin, without relying on the stop crank angle θstop (the position of the piston 132). In this case, in FIG. 5, the fuel injection amount Fi may be set using the solid line Fi(1) showing the fuel injection amount Fi when the piston 132 stops at a position away from top dead center of compression. Furthermore, the fuel injection amount Fi may be set based only on the elapsed time Tstop since the engine 22 is stopped. In this case, the fuel injection amount Fi may be set using the solid line Fi(1) with a relatively large value as the initial value for the intake manifold pressure Pin.

[0041] In the hybrid vehicle 20 of the embodiment, it is provided with a six-speed automatic transmission 45. However, it may be provided with an automatic transmission having four speeds, five speeds, eight speeds, or the like.

[0042] In the hybrid vehicle 20 of the embodiment, it is provided with an engine ECU 24, a motor ECU 34, and an HV ECU 70. However, at least two of these may be integrally configured.

[0043] In the engine device of the embodiment, it is mounted on the hybrid vehicle 20, but it may be mounted on a moving body other than a vehicle or incorporated into equipment.

[0044] 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 problems will be described. In the embodiment, the engine 22 corresponds to the "engine", the clutch K0 corresponds to the "clutch", the hydraulic control device 36 corresponds to the "hydraulic control device", the motor 30 corresponds to the "motor", and the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond to the "control device".

[0045] Note that 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 problems is an example for specifically explaining the form for implementing the invention described in the column of means for solving the problems in the embodiment. Therefore, it does not limit the elements of the invention described in the column of means for solving the problems. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the column of means for solving the problems.

[0046] As described above, the embodiments have been used to explain the forms for implementing the present invention. However, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Industrial Applicability

[0047] The present invention can be used in the manufacturing industry of engine devices and the like.

Explanation of Reference Numerals

[0048] 20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 24 Engine ECU, 25 Starter motor, 26 Alternator, 30 Motor, 30a Rotation position sensor, 31 Rotation shaft, 32 Inverter, 34 Motor ECU, 36 Hydraulic control device, 37 Hydraulic circuit, 40 Automatic transmission, 41 Input shaft, 41a Rotational speed sensor, 42 Output shaft, 42a Rotational speed sensor, 43 Torque converter, 44 Transmission input shaft, 44a Rotational speed sensor, 45 Automatic transmission, 48 Differential gear, 49 Driving wheel, 60 High-voltage battery, 61 High-voltage side power line, 62 Low-voltage battery, 63 Low-voltage side power line, 64 DC / DC converter, 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, 87 Vehicle speed sensor, 122 Air cleaner, 123 Intake pipe, 123a Airflow meter, 123t Temperature sensor, 124 Throttle valve, 124a Throttle valve position sensor, 125 Surge tank, 125a Pressure sensor, 126 Port injection valve, 127 In-cylinder injection valve, 128 Intake valve, 129 Combustion chamber, 130 Spark plug, 132 Piston, 133 Exhaust valve, 134 Exhaust pipe, 135 Purification device, 135a Purification catalyst, 136 PM filter, 136a Differential pressure sensor, 137 Front air-fuel ratio sensor, 138 Rear air-fuel ratio sensor, 140 Crank position sensor, 142 Water temperature sensor, 144 Cam position sensor, K0 Clutch.

Claims

【Claim 1】 An engine device comprising: an engine having an in-cylinder injection valve; a motor; a clutch connected to the crankshaft of the engine and the motor; a hydraulic control device having a hydraulic circuit for the clutch and controlling the hydraulic pressure of the hydraulic circuit; and a control device for controlling the engine, the motor, and the hydraulic control device, wherein when starting the engine, the control device performs fast filling on the hydraulic circuit for the clutch, waits for a constant pressure, then semi-engages the clutch, cranks the engine by the motor, and after semi-engaging the clutch, performs fuel injection and ignition on the cylinder that first reaches top dead center of compression in the engine so as to start the engine, and controls the engine, the motor, and the hydraulic control device accordingly; the control device prohibits fuel injection and ignition in the engine until the semi-engagement of the clutch is started; An engine device characterized by the above.

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