Hybrid vehicles

Abstract

To suppress inconvenience caused by injection quantity in which the injection quantity at the time of deposit removal processing and decompression processing thereafter is less than minimum fuel injection.SOLUTION: A hybrid vehicle comprises: an engine with a cylinder injection valve; a fuel supply system which supplies the cylinder injection valve with fuel; a motor which can generate electric power through power outputted from the engine to be capable of outputting power for travel; and a power storage device which exchanged electric power with the motor. A deposit removal processing is performed during forced charging processing of the power storage device in which fuel pressure supplied to the cylinder injection valve is a prescribed pressure higher than normal pressure to inject fuel from the cylinder injection valve so as to remove deposit adhered to the cylinder injection valve. The forced charging processing continues until the fuel pressure returns to the normal pressure after completing the deposit removal processing.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle equipped with an engine having a direct injection valve and a motor. [Background technology]

[0002] One conventional technique proposed for this type of technology is to suppress deposit buildup on an in-cylinder injection valve by adjusting the pressure of the fuel supplied to the in-cylinder injection valve according to the nozzle temperature of the in-cylinder injection valve (see, for example, Patent Document 1).When a certain amount of deposits has accumulated on the in-cylinder injection valve, a deposit removal process is generally performed in which the pressure of the fuel supplied to the in-cylinder injection valve is increased and fuel is injected from the in-cylinder injection valve to remove the deposits. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-166384 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the deposit removal process described above, the pressure of the fuel supplied to the in-cylinder injection valve is increased before the fuel is injected from the in-cylinder injection valve. Therefore, during low-load operation, such as when the engine is idling, the required fuel injection amount may be less than the minimum fuel injection amount. In this case, the in-cylinder injection valve injects the minimum fuel injection amount, resulting in an excessive fuel injection amount. If the intake air amount is not adjusted, unburned fuel will be discharged, worsening emissions. Adjusting the intake air amount results in excessive engine output. Furthermore, even after the deposit removal process is completed, fuel injection is required to reduce the pressure of the fuel supplied to the in-cylinder injection valve to normal pressure. Therefore, the fuel injection amount may be excessive, just as during the deposit removal process.

[0005] The hybrid vehicle of the present invention has as its main object to prevent inconveniences caused by the fuel injection amount being less than the minimum fuel injection amount during deposit removal processing or the subsequent pressure reduction processing. [Means for solving the problem]

[0006] The hybrid vehicle of the present invention employs the following means to achieve the above-mentioned main object.

[0007] The hybrid vehicle of the present invention is an engine having a direct injection valve; a fuel supply device that supplies fuel to the direct injection valve; a motor capable of generating electricity using power output from the engine and outputting power for traveling; a power storage device that exchanges power with the motor; a control device that controls the engine, the fuel supply device, and the motor; A hybrid vehicle comprising: The control device performs a deposit removal process for removing deposits adhering to the in-cylinder injection valve by injecting fuel from the in-cylinder injection valve at a fuel pressure higher than a normal pressure while performing a forced charging process for the power storage device, and continues the forced charging process until the fuel pressure is returned to the normal pressure after the deposit removal process is completed. It is characterized by:

[0008] In the hybrid vehicle of the present invention, deposit removal processing, which removes deposits adhering to the in-cylinder injection valves by injecting fuel from the in-cylinder injection valves at a predetermined pressure higher than the normal pressure, is performed while forced charging of the power storage device is being performed. Examples of forced charging of the power storage device include controlling the engine so that it outputs more power than the driving power required for driving, and controlling the motor to generate power using the power output from the engine minus the driving power, and charging the power storage device with the generated power. By performing the deposit removal processing while forced charging of the power storage device is being performed, the deposit removal processing is performed while the engine is outputting a certain amount of power, allowing the required fuel injection amount to be equal to or greater than the minimum fuel injection amount, thereby avoiding problems (such as worsening emissions and excessive engine output) that would occur if the required fuel injection amount were less than the minimum fuel injection amount. Note that "executing the deposit removal process while performing the forced charging process for the power storage device" includes cases where the forced charging process for the power storage device is performed prior to the deposit removal process when performing the deposit removal process, or cases where the deposit removal process is performed while performing the forced charging process for the power storage device. Furthermore, since the forced charging process is continued until the fuel pressure is returned to normal pressure after the deposit removal process is completed, the required fuel injection amount can be equal to or greater than the minimum fuel injection amount when the pressure is reduced after the deposit removal process is completed, thereby avoiding problems caused by the required fuel injection amount being less than the minimum fuel injection amount. Note that "continuing the forced charging process until the fuel pressure is returned to normal pressure after the deposit removal process is completed" also includes cases where the forced charging process is forcibly continued until the fuel pressure returns to normal pressure, where the forced charging process is forcibly continued for the time required to return the fuel pressure to normal pressure after the deposit removal process is completed, and where the deposit removal process is terminated before the forced charging process is terminated for the time required to return the fuel pressure to normal pressure. As a result, it is possible to prevent inconveniences caused by the fuel injection amount being less than the minimum fuel injection amount during deposit removal processing or the subsequent pressure reduction processing.

[0009] The engine may have an in-cylinder injection valve located near the center of the top of the cylinder and an ignition plug located near the in-cylinder injection valve. In this configuration, the nozzle temperature of the in-cylinder injection valve increases, making it easier for thermosetting deposits to form. To remove these deposits, the fuel pressure supplied to the in-cylinder injection valve must be increased. Therefore, when the deposit removal process is performed during low-load operation of the engine, the required fuel injection amount tends to be less than the minimum fuel injection amount, which can be appropriately addressed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the outline of the configuration of an engine 22. [Figure 3] 4 is a flowchart showing an example of a deposit removal process executed by an engine ECU 24. [Figure 4] 10 is a flowchart showing an example of a deposit removal process according to a modified example. [Figure 5] 10 is a flowchart showing an example of a deposit removal process according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, a mode for carrying out the present invention will be described using examples. [Example]

[0012] Fig. 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to one embodiment of the present invention. Fig. 2 is a 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 the 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.

[0013] The engine 22 is configured as a six-cylinder internal combustion engine that uses fuel such as gasoline or diesel and outputs power through four strokes: intake, compression, expansion (explosive combustion), and exhaust. As shown in FIG. 2, the engine 22 has a port injection valve 126 that injects fuel supplied from a fuel supply device 150 via a low-pressure supply pipe 153 into an intake port, and an in-cylinder injection valve 127 that injects fuel supplied from the fuel supply device 150 via a high-pressure supply pipe 158 into a cylinder. The in-cylinder injection valve 127 is disposed approximately at the center of the top of a combustion chamber 129 and injects fuel in a spray form. The spark plug 130 is disposed near the in-cylinder injection valve 127 so that it can ignite the fuel sprayed from the in-cylinder injection valve 127 in a spray form. The port injection valve 126 and the in-cylinder injection valve 127 enable the engine 22 to operate in any of a port injection mode, an in-cylinder injection mode, and a common injection mode. In the port injection mode, air purified by an air cleaner 122 is drawn into an intake pipe 123 and passes through a throttle valve 124 and a surge tank 125. At the same time, fuel is injected from a port injection valve 126 downstream of the surge tank 125 in the intake pipe 123 to mix the air and fuel. This mixture is then drawn into a combustion chamber 129 via an intake valve 128 and is explosively combusted by an electric spark from an ignition plug 130. The reciprocating motion of a piston 132, which is pushed down within the cylinder bore by the energy of the fuel, is converted into rotational motion of the crankshaft 23. In the direct injection mode, as in the port injection mode, air is drawn into the combustion chamber 129, and fuel is injected from a direct injection valve 127 during the intake stroke or compression stroke. The fuel is explosively combusted by an electric spark from the ignition plug 130 to generate rotational motion of the crankshaft 23. In the common injection mode, fuel is injected from port injection valve 126 when air is drawn into combustion chamber 129, and fuel is injected from in-cylinder injection valve 127 during the intake stroke and compression stroke, and the fuel is explosively burned by an electric spark from spark plug 130, generating rotational motion of crankshaft 23. These injection modes are switched based on the operating state of engine 22. Exhaust gas discharged from combustion chamber 129 through exhaust valve 133 into exhaust pipe 134 is discharged into the outside air via purification device 135.The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components in the exhaust gas, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

[0014] The fuel supply device 150 is configured as a device that supplies fuel in a fuel tank 151 to the port injection valves 126 and the in-cylinder injection valves 127 of the engine 22. The fuel supply device 150 includes the fuel tank 151, a feed pump 152, a low-pressure supply pipe 153, a check valve 154, a relief pipe 155, a relief valve 156, a high-pressure pump 157, and a high-pressure supply pipe 158.

[0015] Feed pump 152 is configured as an electric pump that operates by receiving power from a battery (not shown), and is disposed in fuel tank 151. Feed pump 152 supplies fuel from fuel tank 151 to low-pressure supply pipe 153. Low-pressure supply pipe 153 is connected to port injection valve 126. Check valve 154 is provided in low-pressure supply pipe 153, and allows fuel to flow in the direction from feed pump 152 to port injection valve 25, while restricting fuel flow in the opposite direction.

[0016] Relief pipe 155 is connected to low-pressure supply pipe 153 and fuel tank 151. Relief valve 156 is provided in relief pipe 155, and closes when the fuel pressure in low-pressure supply pipe 153 is below threshold Pflolim, and opens when the fuel pressure in low-pressure supply pipe 153 is equal to or higher than threshold Pflolim. When relief valve 156 opens, some of the fuel in low-pressure supply pipe 153 is returned to fuel tank 151 via relief pipe 155. In this way, the fuel pressure in low-pressure supply pipe 153 is prevented from becoming excessive.

[0017] High-pressure pump 157 is driven by power from engine 22 (in this embodiment, rotation of the intake camshaft that opens and closes intake valve 128), and is configured as a pump that pressurizes fuel in low-pressure supply pipe 153 and supplies it to high-pressure supply pipe 158. High-pressure pump 157 has an electromagnetic valve 157a connected to its intake port that opens and closes when pressurizing the fuel, a check valve 157b connected to its discharge port that regulates backflow of fuel and maintains the fuel pressure in high-pressure supply pipe 158, and a plunger 157c that is actuated (moves up and down in FIG. 1 ) by rotation of engine 22 (rotation of the intake camshaft). When the electromagnetic valve 157a is opened while the engine 22 is running, the high-pressure pump 157 draws in fuel from the low-pressure supply pipe 153, and when the electromagnetic valve 157a is closed, the high-pressure pump 157 pressurizes the fuel to be supplied to the high-pressure supply pipe 158 by intermittently sending the fuel compressed by the plunger 157c to the high-pressure supply pipe 158 via the check valve 157b.

[0018] The operation of the engine 22 is controlled by an engine ECU 24. The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, although these are not shown.

[0019] Signals from various sensors required for controlling the operation of the engine 22 are input via an input port to the engine ECU 24. Examples of signals input to the engine ECU 24 include a crank angle θcr from a crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and a coolant temperature Tw from a water temperature sensor 142 that detects the temperature of the coolant for the engine 22. Other examples of signals input to the engine ECU 24 include cam angles θci and θco from a cam position sensor 144 that detects the rotational position of an intake camshaft that opens and closes the intake valve 128 and the rotational position of an exhaust camshaft that opens and closes the exhaust valve 133. Other examples include a throttle opening TH from a throttle valve position sensor 124a that detects the position of the throttle valve 124, an intake air amount Qa from an air flow meter 123a attached upstream of the throttle valve 124 in the intake pipe 123, an intake air temperature Ta from a temperature sensor 123t attached upstream of the throttle valve 124 in the intake pipe 123, and a surge pressure Ps from a pressure sensor 125a attached to the surge tank 125. Other examples include a front air-fuel ratio AF1 from a front air-fuel ratio sensor 137 attached upstream of the purification device 135 in the exhaust pipe 134, and a rear air-fuel ratio AF2 from a rear air-fuel ratio sensor 138 attached between the purification device 135 and the PM filter 136 in the exhaust pipe 134. Other examples include the fuel temperature Tftnk from a fuel temperature sensor 151t attached to the fuel tank 151, the rotation speed Np of the feed pump 152 from a rotation speed sensor 152a attached to the feed pump 152, the low-pressure fuel pressure (the pressure of the fuel supplied to the port injection valve 126) PL from a fuel pressure sensor 153p attached to the low-pressure supply pipe 153 near the port injection valve 126 (e.g., a low-pressure delivery pipe), and the high-pressure fuel pressure (the pressure of the fuel supplied to the in-cylinder injection valve 127) PH from a fuel pressure sensor 158p attached to the high-pressure supply pipe 158 near the in-cylinder injection valve 127 (e.g., a high-pressure delivery pipe).

[0020] The engine ECU 24 outputs various control signals via an output port for controlling the operation of the engine 22. Examples of 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. Other examples include a control signal to the feed pump 152 of the fuel supply device 150 and a control signal to the electromagnetic valve 157a of the high-pressure pump 157.

[0021] The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140. The engine ECU 24 also calculates the load factor KL (the ratio of the volume of air actually taken in during 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 rotation speed Ne of the engine 22.

[0022] 1, a starter motor 25 for cranking the engine 22 is connected to the crankshaft 23 of the engine 22. The starter motor 25 is connected to a low-voltage power line 63 together with a low-voltage battery 62, and is controlled by the HVECU 70.

[0023] The motor 30 is configured as a synchronous generator motor and has a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core. A rotating shaft 31 to which the rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0 and to an input shaft 41 of an automatic transmission 45. The inverter 32 is used to drive the motor 30 and is connected to a high-voltage power line 61. The motor 30 is rotationally driven by a motor electronic control unit (hereinafter referred to as "motor ECU") 34 controlling the switching of multiple switching elements of the inverter 32.

[0024] The motor ECU 34 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors are input to the motor ECU 34 via the input port. Examples of signals input to the motor ECU 34 include a 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 phase currents Iu and Iv from current sensors that detect the phase currents of each phase of the motor 30. The motor ECU 34 outputs control signals to the inverter 32 via the output port. 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.

[0025] 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 rotary shaft 31 of the motor 30.

[0026] The automatic transmission 40 includes a torque converter 43 and, for example, a six-speed automatic transmission 45. The torque converter 43 is configured as a typical fluid power transmission device and amplifies the torque of the power of an input shaft 41 connected to the rotating shaft 31 of the motor 30 and transmits it to a transmission input shaft 44, which is the input shaft of the automatic transmission 45, or transmits the torque directly without amplifying it. The automatic transmission 45 includes the transmission input shaft 44, an output shaft 42 connected to drive wheels 49 via a differential gear 48, multiple planetary gears, and multiple hydraulically driven friction engagement elements (clutches, brakes). Each of the multiple friction engagement elements has a hydraulic servo configured with a piston, multiple friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, etc. The automatic transmission 45 establishes forward gears from first to sixth gears and reverse gears by engaging and disengaging multiple 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 from a mechanical oil pump or an electric oil pump at a regulated pressure by a hydraulic control device (not shown). The hydraulic control device includes a valve body with multiple oil passages, multiple regulator valves, multiple linear solenoid valves, and the like. This hydraulic control device is controlled by the HVECU 70.

[0027] 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 several hundred volts, and is connected to high-voltage power line 61 together with inverter 32. Low-voltage battery 62 is configured as, for example, a lead-acid battery with a rated voltage of about 12 V or 14 V, and is connected to low-voltage power line 63 together with starter motor 25 and alternator 26. DC / DC converter 64 is connected to high-voltage power line 61 and low-voltage power line 63. DC / DC converter 64 supplies power from high-voltage power line 61 to low-voltage power line 63 while stepping down the voltage.

[0028] The HVECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors are input to the HVECU 70 via the input ports. Examples of signals input to the HVECU 70 include the rotation speed Nin from a rotation speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotation speed Nmi from a rotation speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotation speed Nout from a rotation speed sensor 42a attached to the output shaft 42 of the automatic transmission 40. Other examples of signals input to the HVECU 70 include 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. Other examples include an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87.

[0029] Various control signals are output from the HVECU 70 via an output port. Examples of signals output from the HVECU 70 include a control signal to the starter motor 25 and a control signal to the alternator 26. Other examples include control signals to the clutch K0 and the automatic transmission 40 (hydraulic control device), and a control signal to the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 and the motor ECU 34 via communication ports. The HVECU 70 calculates the rotation speed ratio Gt of the automatic transmission 40 by dividing the rotation speed Nin of the input shaft 41 of the automatic transmission 40 from the rotation speed sensor 41a by the rotation speed Nout of the output shaft 42 of the automatic transmission 40 from the rotation speed sensor 42a.

[0030] In the hybrid vehicle 20 of this embodiment configured as described above, the engine 22, the clutch K0, the motor 30, and the automatic transmission 40 are controlled by cooperative control between the HVECU 70, the engine ECU 24, and the motor ECU 34 to travel in a hybrid driving mode (HV driving mode) or an electric driving mode (EV driving mode). Here, the HV driving mode is a mode in which the clutch K0 is engaged and the vehicle travels 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 travels without using the power of the engine 22.

[0031] In controlling the automatic transmission 40 in the HV driving mode or the EV driving mode, the HVECU 70 first sets a target gear position M* of the automatic transmission 45 based on the accelerator opening Acc and the vehicle speed V. Then, when the gear position M of the automatic transmission 45 matches the target gear position M*, the HVECU 70 controls the automatic transmission 45 so that the gear position M is maintained. On the other hand, when the gear position M and the target gear position M* differ, the HVECU 70 controls the automatic transmission 45 so that the gear position M matches the target gear position M*.

[0032] In controlling the engine 22 and motor 30 in the HV driving mode, the HVECU 70 first sets a required torque Tout* required for driving (required from the output shaft 42 of the automatic transmission 40) based on the accelerator opening Acc and the vehicle speed V. Next, the HVECU 70 sets a value obtained by dividing the required torque Tout* of the output shaft 42 by the rotation speed ratio Gt of the automatic transmission 40 as the required torque Tin* of the input shaft 41. After setting the required torque Tin* of the input shaft 41 in this manner, the HVECU 70 sets a target torque Te* of the engine 22 and a torque command Tm* of the motor 30 so that the required torque Tin* is output to the input shaft 41, and transmits the target torque Te* of the engine 22 to the engine ECU 24 and the torque command Tm* of the motor 30 to the motor ECU 34. Upon receiving the target torque Te*, the engine ECU 24 performs operation control of the engine 22 (intake air amount control, fuel injection control, ignition control, etc.) so that the engine 22 operates at the target torque Te*. When the motor ECU 34 receives the torque command Tm*, it controls the switching of the multiple switching elements of the inverter 32 so that the motor 30 is driven by the torque command Tm*.

[0033] In controlling 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 a torque command Tm* for the motor 30 so that the required torque Tin* is output to the input shaft 41, and transmits the torque command Tm* to the motor ECU 34. Upon receiving the torque command Tm*, the motor ECU 34 performs switching control of the multiple switching elements of the inverter 32 so that the motor 30 is driven by the torque command Tm*.

[0034] Next, the operation of the hybrid vehicle 20 of this embodiment configured as described above will be described, particularly the operation when removing deposits that accumulate near the tip of the direct injection valve 127 of the engine 22. It is believed that thermoplastic deposits accumulate near the tip of the direct injection valve 127 when the tip temperature Test of the direct injection valve 127 is not very high (for example, temperatures below 150°C or 140°C), and that thermosetting deposits accumulate when the tip temperature Test is at or above a certain temperature (for example, 150°C). The tip temperature Test of the direct injection valve 127 is estimated to tend to increase as the intake air amount Qa increases and the coolant temperature Tw increases. Therefore, in this embodiment, the relationship between the intake air amount Qa, the coolant temperature Tw, and the tip temperature Test is determined in advance and stored as a tip temperature setting map, and when the intake air amount Qa and the coolant temperature Tw are given, the tip temperature Test is estimated by deriving the corresponding tip temperature Test from the map.

[0035] As in engine 22 of the embodiment, when in-cylinder injection valve 127 is disposed near spark plug 130 and fuel is injected from in-cylinder injection valve 127 in a spray-like manner and ignition is synchronized with the fuel injection, the tip temperature Test of in-cylinder injection valve 127 becomes relatively high, and thermosetting deposits also accumulate near the tip. Thermoplastic deposits can be removed by injecting fuel at a pressure PH of fuel supplied to in-cylinder injection valve 127 equal to or higher than a first predetermined pressure P1 (e.g., 15 MPa or higher). Thermosetting deposits can be removed by injecting fuel at a pressure (fuel pressure) PH of fuel supplied to in-cylinder injection valve 127 equal to or higher than a second predetermined pressure P2 (e.g., 20 MPa or higher), which is higher than first predetermined pressure P1. For thermoplastic deposits, removal is determined to be necessary when a first counter C1 is counted up each time fuel is injected when the engine 22 cooling water temperature Tw is equal to or higher than a certain temperature (e.g., 70°C), the fuel pressure PH is less than a first predetermined pressure P1, and the estimated tip temperature Test of the direct injection valve 127 is less than 150°C. The first counter C1 is counted down each time fuel is injected when the fuel pressure PH is equal to or higher than the first predetermined pressure P1. For thermosetting deposits, removal is determined to be necessary when a second counter C2 is counted up each time fuel is injected when the engine 22 cooling water temperature Tw is equal to or higher than a certain temperature (e.g., 70°C), the estimated tip temperature Test of the direct injection valve 127 is equal to or higher than 150°C, and the second counter C2 is counted down each time fuel is injected when the fuel pressure PH is equal to or higher than a second predetermined pressure P2. The second counter C2 is counted up each time fuel is injected when the engine 22 cooling water temperature Tw is equal to or higher than a certain temperature (e.g., 70°C), the estimated tip temperature Test of the direct injection valve 127 is equal to or higher than 150°C. The second counter C2 is counted down each time fuel is injected when the fuel pressure PH is equal to or higher than a second predetermined pressure P2. The second counter C2 is counted up each time fuel is injected when the engine 22 cooling water temperature Tw is equal to or higher than a certain temperature (e.g., 70°C), and the estimated tip temperature Test of the direct injection valve 127 ...

[0036] 3 is a flowchart showing an example of a deposit removal process executed by the engine ECU 24 when removing thermosetting deposits. In the deposit removal process, the engine ECU 24 first determines whether removal of thermosetting deposits is requested (step S100). As described above, the determination of whether removal of thermosetting deposits is requested can be made, for example, by determining whether deposit removal is requested when the second counter C2 is equal to or greater than the second predetermined value Cref2, which indicates that a predetermined amount or more of deposits have accumulated near the tip of the direct injection valve 127. If it is determined that removal of thermosetting deposits is not requested, the ECU 24 determines that deposit removal is not necessary and terminates this process.

[0037] If it is determined in step S100 that removal of thermosetting deposits is required, it is determined whether the high-voltage battery 60 is being forcibly charged (step S110), and if it is determined that the high-voltage battery 60 is not being forcibly charged, the high-voltage battery 60 is forcibly charged (step S120). The forcible charging of the high-voltage battery 60 is performed by setting the sum of the traveling power requirement Pdrv required for traveling and the charging power requirement Pchg for the forced charging as the required power Pe* to be output from the engine 22, driving and controlling the engine 22, generating electricity using the power (charging power requirement Pchg) that is the difference between the traveling power requirement Pdrv and the required power Pe*, and charging the high-voltage battery 60 with the generated electricity. Note that when the vehicle is stopped, the traveling power requirement Pdrv is zero, and therefore the engine 22 is controlled and driven to output the charging power requirement Pchg from the engine 22.

[0038] When it is determined in step S110 that the high-voltage battery 60 is being forcibly charged, or after the high-voltage battery 60 has been forcibly charged in step S120, the end of the forcible charging of the high-voltage battery 60 is prohibited (step S130), and a process for removing thermosetting deposits is performed (step S140). The process for removing thermosetting deposits can be performed, for example, by setting the pressure (fuel pressure) PH of the fuel supplied to the in-cylinder injection valve 127 to a second predetermined pressure P2 or higher (e.g., 20 MPa or higher) and injecting fuel from the in-cylinder injection valve 127 until a second counter C2, which counts down each time fuel is injected, reaches 0. Now, consider a case in which the process for removing thermosetting deposits is performed while the engine 22 is idling, rather than while the high-voltage battery 60 is being forcibly charged. When fuel is injected from direct injection valve 127 with fuel pressure PH set to second predetermined pressure P2 (e.g., 20 MPa), the minimum fuel injection amount Qmin that can be injected from direct injection valve 127 may be greater than the idle fuel injection amount Qidl required for idling engine 22. In this case, direct injection valve 127 injects fuel at minimum fuel injection amount Qmin, resulting in an amount of fuel that is excessive relative to the idle fuel injection amount Qidl. In this case, the fuel injection amount becomes excessive, and if the intake air amount Qa is not adjusted, unburned fuel will be discharged, worsening emissions. If the intake air amount Qa is adjusted, the output of engine 22 will become excessive, causing unexpected acceleration of engine 22 or output of unexpected torque. If the thermosetting deposit removal process is performed during forced charging of the high-voltage battery 60 as in the embodiment, the fuel injection amount Qf required to output the required charging power Pchg from the engine 22 can be made equal to or greater than the minimum fuel injection amount Qmin, so that the fuel injection amount Qf is injected from the in-cylinder injection valve 127, thereby preventing deterioration of emissions, unexpected acceleration of the engine 22, and unexpected torque output.

[0039] When the deposit removal process is completed, a pressure reduction process is executed (step S150) to reduce the pressure (fuel pressure) PH of the fuel supplied to the direct injection valve 127 to a normal pressure required for the engine 22 to output the required power Pe*. The pressure reduction process can be performed by injecting fuel from the direct injection valve 127 until the fuel pressure PH reaches the normal pressure. Because the forced charging of the high-voltage battery 60 continues during this pressure reduction process, the fuel injection amount Qf of the direct injection valve 127 becomes less than the minimum fuel injection amount Qmin, and problems that would occur if the direct injection valve 127 were to inject fuel at the minimum fuel injection amount Qmin can be prevented, such as worsening of emissions, unexpected revving up of the engine 22, and unexpected torque output.

[0040] When the pressure reduction process is completed, the forced charging of the high-voltage battery 60 is permitted to end (step S160), and this process ends. The forced charging of the high-voltage battery 60 is requested to end when the power storage percentage SOC of the high-voltage battery 60 is equal to or greater than a predetermined threshold, and ends when it is confirmed that the forced charging of the high-voltage battery 60 is permitted to end.

[0041] In the hybrid vehicle 20 of the embodiment, thermosetting deposits accumulated near the tip of the in-cylinder injection valve 127 are removed during forced charging of the high-voltage battery 60, thereby making it possible to set the fuel injection amount Qf of the in-cylinder injection valve 127 equal to or greater than the minimum fuel injection amount Qmin. This prevents problems that would occur if the fuel injection amount Qf of the in-cylinder injection valve 127 were less than the minimum fuel injection amount Qmin and the in-cylinder injection valve 127 were to inject fuel at the minimum fuel injection amount Qmin, such as worsening emissions, unexpected acceleration of the engine 22, and unexpected torque output. Furthermore, in the hybrid vehicle 20 of the embodiment, after the removal of the thermosetting deposits is completed, the high-voltage battery 60 continues to be forcedly charged until the fuel pressure PH reduction process is completed. This prevents problems that would occur if the fuel injection amount Qf of the in-cylinder injection valve 127 were less than the minimum fuel injection amount Qmin and the in-cylinder injection valve 127 were to inject fuel at the minimum fuel injection amount Qmin, even when the fuel pressure PH is reduced. As a result, the fuel injection amount Qf of the in-cylinder injection valve 127 during the thermosetting deposit removal process or the subsequent pressure reduction process becomes less than the minimum fuel injection amount Qmin, and the inconvenience of fuel injection from the in-cylinder injection valve 127 being performed at the minimum fuel injection amount Qmin, which is greater than the fuel injection amount Qf, can be suppressed.

[0042] In the hybrid vehicle 20 of the embodiment, if the removal of thermosetting deposits is requested but the high-voltage battery 60 is not being forcibly charged, the high-voltage battery 60 is forcibly charged to remove the deposits. However, if the removal of thermosetting deposits is requested but the high-voltage battery 60 is not being forcibly charged, the deposits may not be removed. In this case, the deposit removal process of FIG. 4 may be executed instead of the deposit removal process of FIG. 3.

[0043] In the deposit removal process of Fig. 4, if it is determined in steps S100 and S110 that removal of thermosetting deposits is not requested, or if it is determined that removal of thermosetting deposits is requested but that forced charging of the high-voltage battery 60 is not being performed, the process ends without executing the deposit removal process. If it is determined in steps S100 and S110 that removal of thermosetting deposits is requested and that forced charging of the high-voltage battery 60 is being performed, the process prohibits termination of forced charging of the high-voltage battery 60 (step S130) and executes the thermosetting deposit removal process (step S140). Then, once deposit removal is completed, a pressure reduction process is executed to inject fuel from the in-cylinder injection valve 127 until the fuel pressure PH reaches the normal pressure (step S150), and then the forced charging of the high-voltage battery 60 is permitted to end (step S160), and the process ends. Even in this case, the same effects as those of the embodiment are achieved.

[0044] In the hybrid vehicle 20 of the embodiment, when a thermosetting deposit removal process is performed during forced charging of the high-voltage battery 60, the forced charging of the high-voltage battery 60 is prohibited from being terminated before the deposit removal process is performed, and is permitted to be terminated after the pressure reduction process following the deposit removal process is completed. However, when a thermosetting deposit removal process is performed during forced charging of the high-voltage battery 60, the forced charging of the high-voltage battery 60 may not be prohibited from being terminated before the deposit removal process is performed, and the deposit removal process and pressure reduction process may be completed before the forced charging of the high-voltage battery 60 is completed. For example, the deposit removal process of FIG. 5 may be performed instead of the deposit removal process of FIG. 4.

[0045] In the deposit removal process of FIG. 5, if it is determined in steps S100 and S110 that removal of thermosetting deposits is not requested, or if it is determined that removal of thermosetting deposits is requested but that forced charging of the high-voltage battery 60 is not being performed, the process ends without executing the deposit removal process. If it is determined in steps S100 and S110 that removal of thermosetting deposits is requested and that forced charging of the high-voltage battery 60 is being performed, the deposit removal process begins (step S200), and steps S210 to S230 are repeated until the deposit removal process ends. This repeated process determines whether a predetermined time has elapsed before the forced termination of the high-voltage battery 60 ends (step S210). Here, the predetermined time is slightly longer than the time required to perform the pressure reduction process in which fuel is injected from the direct injection valve 127 until the fuel pressure PH reaches the normal pressure, and may be, for example, 3 or 4 seconds. If it is determined in step S210 that the predetermined time for the forced shutdown of the high-voltage battery 60 to end has not yet arrived, it is determined whether the deposit removal process has ended (step S230). If it is determined that the deposit removal process has not yet arrived, the process returns to step S210, where it is determined whether the predetermined time for the forced shutdown of the high-voltage battery 60 to end has arrived. Therefore, these processes are processes that wait for the deposit removal process to end by the predetermined time before the forced shutdown of the high-voltage battery 60 ends. If it is determined in step S210 that the predetermined time for the forced shutdown of the high-voltage battery 60 to end has arrived, the deposit removal process is forcibly terminated (step S220), and it is determined whether the deposit removal process has ended (step S230). In this case, the deposit removal process has been forcibly terminated, and therefore it is determined that the deposit removal process has ended. Therefore, when it is determined in step S230 that the deposit removal process has ended, it is when the deposit removal process has ended before a predetermined time before the forced charging of the high-voltage battery 60 is completed, or when the deposit removal process has been forcibly terminated before a predetermined time before the forced charging of the high-voltage battery 60 is completed.If it is determined in step S230 that the deposit removal process has ended, a pressure reduction process is performed in which fuel is injected from the in-cylinder injection valve 127 until the fuel pressure PH reaches the normal pressure (step S240), and then this process ends. Even in this case, as in the embodiment, the fuel injection amount Qf of the in-cylinder injection valve 127 during the thermosetting deposit removal process or the subsequent pressure reduction process becomes less than the minimum fuel injection amount Qmin, and it is possible to suppress the inconvenience of fuel injection from the in-cylinder injection valve 127 at the minimum fuel injection amount Qmin, which is greater than the fuel injection amount Qf.

[0046] 5, if the deposit removal process has not been completed by a predetermined time before the forced charging of the high-voltage battery 60 is completed, the deposit removal process is forcibly terminated, and a pressure reduction process is executed in which fuel is injected from the in-cylinder injection valve 127 until the fuel pressure PH reaches the normal pressure within the predetermined time. However, if the deposit removal process has not been completed by the time a request is made to complete the forced charging of the high-voltage battery 60, the deposit removal process may be forcibly terminated and the completion of the forced charging of the high-voltage battery 60 may be delayed by a predetermined time, with the pressure reduction process being executed during that time.

[0047] The hybrid vehicle 20 of the embodiment is equipped with a six-speed automatic transmission 45. However, it may be equipped with a four-speed, five-speed, eight-speed, or other automatic transmission.

[0048] In the hybrid vehicle 20 of the embodiment, an engine 22 having a port injection valve 126 and an in-cylinder injection valve 127 is mounted, but an engine having only an in-cylinder injection valve without a port injection valve may also be mounted.

[0049] In the hybrid vehicle 20 of the embodiment, the engine 22 is equipped with an in-cylinder injection valve 127 located near the center of the top of the combustion chamber 129 and close to the spark plug 130, but it is also possible to equip the engine with an ignition plug located near the center of the top of the combustion chamber and an in-cylinder injection valve located on the side of the combustion chamber.

[0050] The hybrid vehicle 20 of the embodiment is equipped with the engine ECU 24, the motor ECU 34, and the HVECU 70. However, at least two of these may be configured as an integrated unit.

[0051] In the embodiment, the present invention is applied to a hybrid vehicle 20 configured such that the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30 are connected via a clutch K0, and the input shaft 41 and output shaft 42 of the automatic transmission 40 are connected to a differential gear 48 to which the rotating shaft 31 of the motor 30 and drive wheels 49 are connected. However, the present invention may be applied to any hybrid vehicle configuration as long as it is equipped with an engine, a motor that can generate electricity using the power output from the engine and output power for driving, and a storage device that can exchange power with the motor.

[0052] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the engine 22 corresponds to the "engine," the fuel supply device 150 corresponds to the "fuel supply device," the motor 30 corresponds to the "motor," the high-voltage battery 60 corresponds to the "electricity storage device," and the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond to the "control device."

[0053] The correspondence between the main elements of the Examples and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the Examples are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the Examples are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0054] The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms within the scope that does not deviate from the gist of the present invention. [Industrial Applicability]

[0055] The present invention can be used in the engine device manufacturing industry and the like. [Explanation of symbols]

[0056] 20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 24 Engine ECU, 25 Starter motor, 30 Motor, 30a Rotational position sensor, 31 Rotating shaft, 32 Inverter, 34 Motor ECU, 40 Automatic transmission, 41 Input shaft, 41a Speed ​​sensor, 42 Output shaft, 42a Speed ​​sensor, 43 Torque converter, 44 Transmission input shaft, 44a Speed ​​sensor, 45 Automatic transmission, 48 Differential gear, 49 Drive wheels, 60 High-voltage battery, 61 High-voltage power line, 62 Low-voltage battery, 63 Low-voltage 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 air flow 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, 150 fuel supply device, 151 fuel tank, 151t fuel temperature sensor, 152 feed pump, 152a RPM sensor, 153 low pressure supply pipe, 153p fuel pressure sensor, 154 check valve, 155 relief pipe, 156 relief valve, 157 high pressure pump, 157a solenoid valve, 157b check valve, 157c plunger, 158 high pressure supply pipe, 158p fuel pressure sensor, K0 clutch.

Claims

1. An engine having a direct injection valve; a fuel supply device for supplying fuel to the in-cylinder injection valve; a motor capable of generating electricity using the power output from the engine and outputting power for driving the vehicle; a power storage device that exchanges power with the motor; a control device for controlling the engine, the fuel supply device, and the motor; A hybrid vehicle comprising: the control device executes a deposit removal process for removing deposits adhering to the in-cylinder injection valve by injecting fuel from the in-cylinder injection valve at a fuel pressure higher than a normal pressure while performing a forced charging process of the power storage device, and continues the forced charging process until the fuel pressure is returned to the normal pressure by injecting fuel from the in-cylinder injection valve after completion of the deposit removal process. A hybrid vehicle characterized by

2. 2. The hybrid vehicle according to claim 1, The forced charging process is a process of controlling the engine so as to output a power larger than a driving power required for driving from the engine, controlling the motor so as to generate power using a power obtained by subtracting the driving power from the power output from the engine, and charging the power storage device with the generated power by the motor. Hybrid car.

3. 3. The hybrid vehicle according to claim 1 or 2, The engine has an in-cylinder injection valve disposed near the center of the top of a cylinder and an ignition plug disposed near the in-cylinder injection valve. Hybrid car.

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