Engine device

Abstract

To make both good startability of an engine and suppression of shock which may be caused when starting the engine compatible.SOLUTION: An engine device comprises an engine having an injection valve in a cylinder, a motor connected to an output shaft of the engine through a clutch, and a control device that controls the engine, the motor and the clutch. The control device, when bringing the clutch into a half-engagement state to make the motor crank the engine and controlling the engine, the motor and the clutch so that the engine is started by injecting fuel to a cylinder reaching a compression top dead center first or second in the engine and performing ignition, sets a timing of ignition for the cylinder reaching the compression top dead center first, on the basis of a stop crank angle at the time of stopping the engine, target cranking torque at the time of making the motor crank the engine and a rotation speed of the motor.SELECTED DRAWING: Figure 3

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 has been proposed that includes 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 (see, for example, Patent Document 1). In this hybrid vehicle, when the vehicle is running by the motor with the clutch released, 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, the engine speed may surge when the engine is started, resulting in a torque shock. It is preferable that the engine starts to output torque with the rotation speed of the motor as the target rotation speed, but it is preferable to achieve both quick and reliable starting performance and suppression of torque shock. However, if starting performance is prioritized, a large shock will occur, and if shock suppression is prioritized, starting performance will deteriorate.

[0005] The main object of the engine device of the present invention is to achieve both good starting performance of the engine and suppression of shocks that may occur when the engine is started.

Means for Solving the Problems

[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 connected to an output shaft of the engine via a clutch, and a control device for controlling the engine, the motor, and the clutch, when the control device controls the engine, the motor, and the clutch so as to start the engine by semi-engaging the clutch and cranking the engine by the motor and performing fuel injection and ignition on the cylinder that first or second reaches the compression top dead center in the engine, for the cylinder that first reaches the compression top dead center, the ignition timing is set based on the stop crank angle when the engine stops, the target cranking torque when cranking by the motor, and the rotational speed of the motor. It is characterized by this.

[0008] In the engine device of the present invention, 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 for controlling the engine, the motor, and the clutch are provided. The control device controls the engine, the motor, and the clutch so as to semi-engage the clutch and crank the engine by the motor, and perform fuel injection and ignition on the cylinder that reaches the first or second compression top dead center in the engine to start the engine. Whether to perform fuel injection and ignition on the cylinder that reaches the first compression top dead center is determined based on whether the stop crank angle is within a predetermined crank angle range determined in advance. The stop crank angle position of the cylinder that reaches the first compression top dead center is within 180 degrees before the compression top dead center (TDC) in the case of a four-cylinder engine, and within 120 degrees before the compression top dead center in the case of a six-cylinder engine. Therefore, in order to perform fuel injection and ignition (first explosion) on the cylinder that reaches the first 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. For this reason, in order to perform the first explosion well in the cylinder that reaches the first compression top dead center, it is required that the stop crank angle be within the predetermined crank angle range because it is necessary to perform fuel injection and ignition well. And when starting the engine in this way, for the cylinder that reaches the first compression top dead center, the ignition timing is set based on the stop crank angle when the engine is stopped, the target cranking torque when cranking by the motor, and the rotational speed of the motor. By performing fuel injection and ignition (first explosion) on the cylinder that reaches the first compression top dead center in this way, the engine can be started quickly, and by setting the ignition timing based on the stop crank angle, the target cranking torque, and the rotational speed of the motor, shock can be suppressed.

[0009] Note that setting the ignition timing based on the stop crank angle is based on the fact that the farther the stop crank angle is from top dead center of compression (larger as BTDC), the larger the amount of air in the cylinder becomes, and the greater the shock at the first explosion. Therefore, it is preferable to retard the ignition timing to reduce the shock. Setting the ignition timing based on the target cranking torque is based on the fact that the target cranking torque is set to increase as the amount of air in the cylinder that first reaches top dead center of compression increases. The greater the amount of air in the cylinder, the greater the shock, and it is preferable to retard the ignition timing to reduce the shock. Setting the ignition timing based on the rotational speed of the motor is based on the fact that the higher the rotational speed of the motor, the more time is required to make the rotational speed immediately after starting the engine substantially coincide with the rotational speed of the motor. Therefore, it is preferable to increase the torque of the engine even at the first explosion to increase the rotational speed of the engine.

[0010] In the engine device of the present invention, for the ignition timing of the cylinder that first reaches top dead center of compression, the control device may be configured to set using a predetermined map such that the ignition timing becomes more retarded as the stop crank angle is farther from top dead center of compression of the first target cylinder, the ignition timing becomes more retarded as the target cranking torque is larger, and the ignition timing becomes more advanced as the rotational speed of the motor is higher. By doing so, an appropriate ignition timing for reducing shock can be quickly set.

[0011] In the engine device of the present invention, for the cylinders that reach top dead center of compression after the second cylinder, the control device may set the ignition timing based on the target cranking torque, the rotational speed of the motor, and the rotational speed of the engine. In this case, for the ignition timing of the cylinders that reach top dead center of compression after the second cylinder, the control device may be configured to use a map determined in advance such that the ignition timing is retarded as the target cranking torque increases and advanced as the rotational speed of the motor increases. Note that the map may be determined so as to guard the retarded side at a timing corresponding to the rotational speed of the engine. As a result, the rotational speed of the engine can be quickly brought close to the rotational speed of the motor. Note that setting the ignition timing based on the target cranking torque is based on the fact that when the target cranking torque is large, the rotational speed of the engine increases quickly and it is easy to blow up. Setting the ignition timing based on the rotational speed of the motor is based on the necessity of quickly making the rotational speed of the engine 22 substantially coincide with the rotational speed of the motor. Setting the ignition timing based on the rotational speed of the engine is based on the fact that the ignition timing is correlated with the rotational speed of the engine.

Brief Description of Drawings

[0012]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0013] Next, embodiments for carrying out the present invention will be described using examples.

Examples

[0014] 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 an 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, 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.

[0015] 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 diesel 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 also 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 from 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 combining the purification function of a three-way catalyst and the collection function for particulate matter may be used.

[0016] The engine 22 is under operation control by the engine ECU 24. The engine ECU 24 includes, although not shown, a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors necessary for operation control 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 position of the intake camshaft that opens and closes the intake valve 128 and the rotational position of 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 amount 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) across the PM filter 136.

[0017] 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 spark plug 130.

[0018] The engine ECU 24 is connected to the HV ECU 70 via a communication port. The engine ECU 24 calculates the rotational 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 volume Qa from the air flow meter 123a and the rotational 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 rotational speed Ne of the engine 22 and the load factor KL.

[0019] 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.

[0020] The motor 30 is configured as a synchronous generator motor, and includes a rotor in which permanent magnets are embedded in the rotor core, and a stator in which three-phase coils are wound around the stator core. The rotating shaft 31, to which the rotor of this motor 30 is fixed, is connected to the crankshaft 23 of the engine 22 via the 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 the 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.

[0021] 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 the 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 the 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 the 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.

[0022] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and is controlled by the HVECU 70 to connect and disconnect the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30.

[0023] The automatic transmission 40 has a torque converter 43 and, for example, a six-speed automatic transmission 45. The torque converter 43 is configured as a general fluid transmission device, and amplifies and transmits the power of the input shaft 41 connected to the rotating shaft 31 of the motor 30 to the transmission input shaft 44 which is the input shaft of the automatic transmission 45, or transmits it as it is without amplifying the torque. The automatic transmission 45 has 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 constituted by 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 has 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.

[0024] 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 a voltage step-down.

[0025] The HVECU 70 includes, although not shown, a microcomputer 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 a voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from a current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from a 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 operating 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.

[0026] Various control signals are output from the HVECU 70 via the output ports. Examples of the signals output from the HVECU 70 include control signals to the starter motor 25 and control signals to the alternator 26. Also included are control signals to the clutch K0 and the automatic transmission 40 (hydraulic control device), and control signals 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 speed 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.

[0027] 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 to run 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 clutch K0 is engaged and the vehicle runs using the power of the engine 22, and the EV driving mode is a mode in which the clutch K0 is disengaged and the vehicle runs without using the power of the engine 22.

[0028] 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*.

[0029] 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 the output shaft 42 of the automatic transmission 40) required for driving based on the accelerator opening Acc and the vehicle speed V. Subsequently, the 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 thus set, 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 driving 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*.

[0030] 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*.

[0031] In the embodiment, as the engine device, the engine 22, the clutch K0, the motor 30, the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond.

[0032] Next, the operation of the hybrid vehicle 20 of the embodiment thus configured will be described, particularly the start of the engine 22 when the engine 22 is operating intermittently. In the embodiment, when the engine 22 is operating intermittently, the start of the engine 22 basically involves semi-engaging (slip-engaging) the clutch K0 to output the target cranking torque Tcr* from the motor 30 to crank the engine 22, and performing the first fuel injection and ignition (first explosion) in the cylinder that first reaches the compression top dead center (TDC: Top Dead Center) or the cylinder that secondarily reaches the compression top dead center. The selection of whether to perform the first fuel injection and ignition in the cylinder that first reaches the compression top dead center or in the cylinder that secondarily reaches the compression top dead center is basically determined by whether the crank angle (stop crank angle) θstop when the engine 22 is stopped is within a predetermined crank angle range (for example, BTDC40~80 (Before TDC 40~80 degrees), etc.) where the first explosion can be performed in the cylinder that first reaches the compression top dead center. That is, when the stop crank angle θstop is within the predetermined crank angle range, the first fuel injection and ignition are performed in the cylinder that first reaches the compression top dead center, and when the stop crank angle θstop is not within the predetermined crank angle range, the first fuel injection and ignition are performed in the cylinder that secondarily reaches the compression top dead center.

[0033] Also, in the embodiment, in order to enable starting from the cylinder that first reaches the compression top dead center, the throttle valve 124 is temporarily opened immediately before the engine 22 stops and the engine is stopped within a predetermined crank angle range. Temporarily opening the throttle valve 124 immediately before the engine 22 stops is to increase the amount of air in the cylinder that stops during the compression stroke. Note that fuel injection in the cylinder that first reaches the compression top dead center and the cylinder that secondarily reaches the compression top dead center is performed by injecting the fuel injection amount set based on the stop crank angle θstop and the elapsed time since the engine 22 stopped until reaching the compression top dead center. The fact that the fuel injection amount is based on the elapsed time since the engine 22 stopped is based on the fact that the pressure in the cylinder that stops during the compression stroke decreases with the passage of time and the amount of air in the cylinder decreases. The throttle opening TH at the start of the engine 22 basically uses a predetermined opening (for example, 5%). Ignition is performed by setting the ignition timing by the starting ignition timing setting process illustrated in FIG. 3. In this starting ignition timing setting process, control of the clutch K0 is executed by the HVECU 70, and setting of the ignition timing Ti is executed by the engine ECU 24.

[0034] When the starting ignition timing setting process is executed, first, the clutch K0 is semi-engaged (slip engaged) to output the target cranking torque Tcr* from the motor 30 and start the cranking of the engine 22 (step S100). This process is performed by transmitting a control signal from the HVECU 70 to a hydraulic control device (not shown) so that the clutch K0 is semi-engaged (slip engaged), and transmitting the torque that is 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 that has received the control signal adjusts the hydraulic pressure to a predetermined value 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 stop crank angle θstop and the elapsed time since the engine 22 was stopped. The reason for basing on the stop crank angle θstop is to consider the pressure in the cylinder stopped in the compression stroke, and the reason for basing 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 with the passage of time.

[0035] Subsequently, it is determined whether the cylinder is the first to reach the compression top dead center (step S110). When it is determined that the cylinder is the first to reach the compression top dead center, 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 S120). In the cylinder where fuel injection and ignition are first performed, the greater the stop crank angle θstop is from its compression top dead center (larger as BTDC), the greater the amount of air in the cylinder. Since the shock at the first explosion becomes larger when the amount of air in the cylinder is large, it is preferable to retard the ignition timing to reduce the shock. Therefore, in the embodiment, the ignition timing Ti is set so as to be retarded more as the stop crank angle θstop is farther from the compression top dead center (larger as BTDC) within the retard limit range where ignition is possible. 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, as described above. 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 retard limit range 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 drive, it is necessary to control the rotational speed Ne of the engine 22 to substantially 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 substantially 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. Therefore, in the embodiment, the ignition timing Ti is set to be advanced more as the rotational speed Nmg of the motor 30 is larger. From these, in the embodiment, 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 is determined in advance by experiments, analysis, machine learning, etc., stored as a first ignition timing setting map, and 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 first ignition timing setting map for setting.

[0036] When it is determined in step S110 that the cylinder does not first reach the compression top dead center (but is the cylinder that reaches the compression top dead center after the second one), the ignition timing Ti is set based on the target cranking torque Tcr*, the rotational speed Nmg of the motor 30, and the rotational speed Ne of the engine 22 (step S130). When the target cranking torque Tcr* is large, the rotational speed Ne of the engine 22 rises quickly and it is easy to blow up. Therefore, in the embodiment, the ignition timing Ti is set so as to retard more as the target cranking torque Tcr* is larger within the range of the retard limit where ignition is possible. Since it is necessary to quickly control the rotational speed Ne of the engine 22 to substantially match the rotational speed Nmg of the motor 30, in the embodiment, the ignition timing Ti is set so as to advance more as the rotational speed Nmg of the motor 30 is larger. Since the ignition timing Ti is correlated with the rotational speed Ne of the engine 22, in the embodiment, the ignition timing Ti is set according to the rotational speed Ne of the engine 22. From these facts, in the embodiment, the relationship between the target cranking torque Tcr*, the rotational speed Nmg of the motor 30, the rotational speed Ne of the engine 22, and the ignition timing Ti is determined in advance by experiments, analysis, machine learning, etc., stored as a second ignition timing setting map, and when the target cranking torque Tcr*, the rotational speed Nmg of the motor 30, and the rotational speed Ne of the engine 22 are given, the corresponding ignition timing Ti is derived from the second ignition timing setting map and set.

[0037] When the ignition timing Ti is set in this way, it is determined whether the condition for releasing the clutch K0 is satisfied (step S140). Examples of the condition for releasing the clutch K0 include that the number of times passing the top dead center of compression is equal to or greater than a predetermined number of times (for example, 2 or 3 times), the rotational speed Ne of the engine 22 is increasing, and the rotational speed Ne of the engine 22 is equal to or greater than a threshold value based on the rotational speed Nmg of the motor 30. In the embodiment, it is determined that the condition for releasing the clutch K0 is satisfied when all of the above three conditions are satisfied. When it is determined that the condition for releasing the clutch K0 is not satisfied, the process returns to step S110 for determining whether the ignition in the cylinder that reaches the top dead center of compression next is the first ignition (the first ignition). Therefore, the processes of steps S110 to S140 are repeated until the condition for releasing the clutch K0 is satisfied.

[0038] When it is determined in step S140 that the condition for releasing the clutch K0 is satisfied, the clutch K0 is released by controlling the hydraulic control device so that the clutch K0 waits at a hydraulic pressure that does not cause slip engagement (step S150). This is set as constant pressure standby in order to quickly engage the next clutch K0.

[0039] When the clutch K0 is released, the process of setting the ignition timing Ti so that the rotational speed Ne of the engine 22 substantially matches the rotational speed Nmg of the motor 30 is repeated until the condition for engaging the clutch K0 is satisfied (steps S160 to S200). Examples of the condition for engaging the clutch K0 include that the difference in rotational speed ΔN between the rotational speed Ne of the engine 22 and the rotational speed Nmg of the motor 30 is less than a threshold value (for example, 50 rpm, 100 rpm, 150 rpm, etc.), and the number of ignition times is equal to or greater than a predetermined number of times (for example, 5, 6, 8, etc.). Note that the intake air amount and fuel injection amount during this repeated process are basically set so that the engine 22 approaches the rotational speed Nmg of the motor 30.

[0040] Until the condition for engaging the clutch K0 is satisfied, the repetitive process first performs a process of setting the ignition timing Ti based on the rotational speed Nmg of the motor 30, the rotational speed Ne of the engine 22, and the intake manifold pressure (inmanifold pressure) Pin at the timing of closing the intake valve 128 (step S160). In the embodiment, the surge pressure Ps from the pressure sensor 125a is used as the inmanifold pressure Pin. As described above, in order to quickly make the rotational speed Ne of the engine 22 substantially coincide with the rotational speed Nmg of the motor 30, the ignition timing Ti is set so as to advance as the rotational speed Nmg of the motor 30 increases. Further, since the ignition timing Ti is correlated with the rotational speed Ne of the engine 22, the ignition timing Ti is set according to the rotational speed Ne of the engine 22. The amount of air in the cylinder increases as the inmanifold pressure Pin at the timing of closing the intake valve 128 is higher, and the output torque from the engine 22 increases as the amount of air in the cylinder is larger. Therefore, in the embodiment, the ignition timing Ti is set so as to retard as the inmanifold pressure Pin at the timing of closing the intake valve 128 is higher. From these facts, in the embodiment, the ignition timing Ti is determined in advance by experiments, analysis, machine learning, etc. based on the relationship between the rotational speed Nmg of the motor 30, the rotational speed Ne of the engine 22, the inmanifold pressure Pin, and the ignition timing Ti, and stored as a third ignition timing setting map. When the rotational speed Nmg of the motor 30, the rotational speed Ne of the engine 22, and the inmanifold pressure Pin are given, the corresponding ignition timing Ti is derived from the third ignition timing setting map and set.

[0041] Subsequently, it is determined whether or not the number of ignition times is equal to or greater than a predetermined number of times (for example, 5 times, 6 times, etc.) (step S170), and it is determined whether or not the absolute value of the differential rotation between the rotational speed Nmg of the motor 30 and the rotational speed Ne of the engine 22 is equal to or greater than a threshold value Nref (step S180). When it is determined that the number of ignition times is equal to or greater than the predetermined number of times and the absolute value of the differential rotational speed between the rotational speed Nmg of the motor 30 and the rotational speed Ne of the engine 22 is equal to or greater than the threshold value Nref, the ignition timing Ti is corrected in a direction in which the rotational speed Ne of the engine 22 approaches the rotational speed Nmg of the motor 30. Specifically, when Nmg > Ne, the ignition timing Ti is advanced by an angle obtained by multiplying the difference between the rotational speed Nmg of the motor 30 and the rotational speed Ne of the engine 22 by a proportionality constant k, and when Nmg < Ne, the ignition timing Ti is retarded. On the other hand, when it is determined that the number of ignition times is less than the predetermined number of times, or when it is determined that the absolute value of the differential rotational speed between the rotational speed Nmg of the motor 30 and the rotational speed Ne of the engine 22 is less than the threshold value Nref even though the number of ignition times is equal to or greater than the predetermined number of times, the above-described correction of the ignition timing Ti is not performed.

[0042] When it is determined in step S200 that the condition for engaging the clutch K0 is satisfied, the clutch K0 is engaged (step S210), and this process is terminated.

[0043] In the engine device mounted on the hybrid vehicle 20 of the embodiment described above, when starting the engine 22 by outputting the target cranking torque Tcr* from the motor 30 with the clutch K0 semi-engaged (slip engagement) to start cranking of the engine 22, when 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 more as the stop crank angle θstop is farther from top dead center of compression (larger as BTDC), so that it retards more as the target cranking torque Tcr* is larger, and so that it advances more as the rotational speed Nmg of the motor 30 is 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 startability of the engine 22 and suppression of the shock that may occur when the engine 22 is started.

[0044] Also, in the engine device mounted on the hybrid vehicle 20 of the embodiment, when starting the engine 22 and performing fuel injection and ignition in the cylinders that reach the compression top dead center after the second one, the ignition timing is set according to the engine speed Ne of the engine 22 such that the later the target cranking torque Tcr* is, the more retarded the ignition timing is, and the higher the rotational speed Nmg of the motor 30 is, the more advanced the ignition timing is. Thereby, the engine speed Ne of the engine 22 can be quickly brought close to the rotational speed Nmg of the motor.

[0045] In the engine device mounted on the hybrid vehicle 20 of the embodiment, when starting the engine 22 and performing fuel injection and ignition in the cylinders that reach the compression top dead center after the second one, the ignition timing Ti is set using a second ignition timing setting map in which the relationships among the target cranking torque Tcr*, the rotational speed Nmg of the motor 30, the engine speed Ne of the engine 22, and the ignition timing Ti are determined in advance. However, the ignition timing Ti may be set using a map determined so as to guard the retard side at a timing corresponding to the engine speed Ne of the engine 22 with respect to the relationships among the target cranking torque Tcr*, the rotational speed Nmg of the motor 30, and the ignition timing Ti.

[0046] The hybrid vehicle 20 of the embodiment 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.

[0047] The hybrid vehicle 20 of the embodiment 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.

[0048] 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.

[0049] 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 "engine", the clutch K0 corresponds to "clutch", the motor 30 corresponds to "motor", and the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond to "control device".

[0050] 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, and thus 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.

[0051] 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

[0052] The present invention can be used in the manufacturing industry of engine devices and the like.

Explanation of Reference Numerals

[0053] 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, 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 Drive 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

1. An engine device comprising: an engine having an in-cylinder injection valve; a motor connected to an output shaft of the engine via a clutch; and a control device configured to control the engine, the motor, and the clutch, when the control device controls the engine, the motor, and the clutch so as to semi-engage the clutch and crank the engine by the motor, and perform fuel injection and ignition on a cylinder that reaches the first or second compression top dead center in the engine to start the engine, for the cylinder that reaches the first compression top dead center, an ignition timing is set based on a stop crank angle when the engine stops, a target cranking torque when cranking by the motor, and a rotational speed of the motor, for the ignition timing of the cylinder that reaches the first compression top dead center, it is set using a predetermined map such that as the stop crank angle moves away from the compression top dead center of the first target cylinder, it becomes more retarded, as the target cranking torque increases, it becomes more retarded, and as the rotational speed of the motor increases, it becomes more advanced, Engine device.

2. The engine device according to Claim 1, wherein the control device sets an ignition timing for cylinders that reach the compression top dead center after the second based on the target cranking torque, the rotational speed of the motor, and the rotational speed of the engine. Engine device.

3. The engine device according to Claim 2, wherein the control device sets the ignition timing for cylinders that reach the compression top dead center after the second using a predetermined map such that as the target cranking torque increases, it becomes more retarded, and as the rotational speed of the motor increases, it becomes more advanced. Engine device.

4. The engine device according to Claim 3, wherein the map is defined to guard the retarded side at a timing corresponding to the rotational speed of the engine. Engine device.

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