Hybrid vehicles

Abstract

To properly deal with a request of removal of a deposit adhering to an in-cylinder injection valve during vehicle stop.SOLUTION: A control device of a hybrid vehicle controls a fuel supply device such that a supply fuel pressure being a pressure of a fuel to be supplied to an in-cylinder injection valve becomes a first fuel pressure when a vehicle is stopped, removal of a deposit adhering to the in-cylinder injection valve is not requested and forcible charge of a power storage device followed by the load operation of an engine is not performed. The control device controls the fuel supply device such that the supply fuel pressure becomes a second fuel pressure higher than the first fuel pressure when the vehicle is stopped, removal of the deposit is requested and forcible charge of the power storage device is performed. The control device controls the fuel supply device such that the supply fuel pressure becomes a third fuel pressure higher than the first fuel pressure but lower than the second fuel pressure when the vehicle is stopped, removal of the deposit is requested and forcible charge of the power storage device is not performed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to hybrid vehicles. [Background technology]

[0002] A conventional technique of this type is a system that performs a deposit removal process when the amount of deposits adhering near the nozzle hole of an engine's in-cylinder injection valve exceeds a tolerance (see, for example, Patent Document 1). The deposit removal process increases the fuel injection pressure of the in-cylinder injection valve to a predetermined pressure to remove deposits from near the nozzle hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-2196 Summary of the Invention [Problem to be solved by the invention]

[0004] If the fuel injection pressure of the in-cylinder injection valve is increased to a predetermined pressure during engine idling when the amount of deposits exceeds the allowable amount, the minimum injection amount that can be injected from the in-cylinder injection valve may be greater than the required injection amount of the in-cylinder injection valve. In this case, the in-cylinder injection valve will inject the minimum injection amount of fuel, resulting in an excessive fuel injection amount, which may cause problems such as worsening of emissions. Based on this, if the fuel injection pressure of the in-cylinder injection valve is sufficiently lowered during engine idling when the amount of deposits exceeds the allowable amount, the amount of deposits that adhere to the in-cylinder injection valve may further increase.

[0005] The hybrid vehicle of the present disclosure has a primary purpose of appropriately dealing with a situation when the vehicle is stopped and removal of deposits adhering to the direct injection valve is required. [Means for solving the problem]

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

[0007] The hybrid vehicle of the present disclosure is a hybrid vehicle including an engine having an in-cylinder injection valve, a fuel supply device that supplies fuel to the in-cylinder injection valve, a motor that is capable of generating electricity using power from the engine and outputting power for driving, an electricity storage device that exchanges electricity with the motor, and a control device that controls the engine, the fuel supply device, and the motor, wherein the control device is configured to: The gist of the invention is that the fuel supply device is controlled so that a supply fuel pressure, which is the pressure of the fuel supplied to the in-cylinder injection valve, becomes a first fuel pressure; when the vehicle is stopped, deposit removal is requested, and the power storage device is being forcibly charged, the fuel supply device is controlled so that the supply fuel pressure becomes a second fuel pressure higher than the first fuel pressure; and when the vehicle is stopped, deposit removal is requested, and the power storage device is not being forcibly charged, the fuel supply device is controlled so that the supply fuel pressure becomes a third fuel pressure higher than the first fuel pressure and lower than the second fuel pressure.

[0008] The hybrid vehicle disclosed herein controls the fuel supply device so that the supply fuel pressure, which is the pressure of fuel supplied to the in-cylinder injection valve, is a first fuel pressure when the vehicle is stopped, deposit removal from the in-cylinder injection valve is not required, and the hybrid vehicle is not performing forced charging of the power storage device accompanied by engine load operation. Furthermore, when the hybrid vehicle is stopped, deposit removal is required, and the power storage device is being forcedly charged, the hybrid vehicle controls the fuel supply device so that the supply fuel pressure is a second fuel pressure higher than the first fuel pressure. "Forced charging of the power storage device" is achieved by operating the engine under load to output a certain amount of power, generating electricity with the motor using power from the engine, and charging the power storage device with the generated power from the motor. The "second fuel pressure" is set to a value within a fuel pressure range that allows deposit removal. This allows the hybrid vehicle to remove deposits. At this time, because the engine is operating under load to output a certain amount of power, the hybrid vehicle can prevent the minimum injection quantity capable of being injected from the direct injection valve from exceeding the required injection quantity of the direct injection valve, thereby preventing an excessive fuel injection quantity and preventing problems such as worsening of emissions. Furthermore, when the hybrid vehicle is stopped, deposit removal is required, and the power storage device is not being forcibly charged, the hybrid vehicle controls the fuel supply device so that the supply fuel pressure is a third fuel pressure that is higher than the first fuel pressure but lower than the second fuel pressure. The hybrid vehicle can prevent an increase in the amount of deposits compared to when the supply fuel pressure is the first fuel pressure. Furthermore, the hybrid vehicle can prevent an excessive fuel injection quantity compared to when the supply fuel pressure is the second fuel pressure. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle 20. [Figure 2] 1 is a schematic diagram of an engine 22 mounted on a hybrid vehicle 20. FIG. [Figure 3] 4 is a flowchart showing an example of a fuel pressure control routine. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a hybrid vehicle 20. Fig. 2 is a schematic configuration diagram of an engine 22 mounted on the hybrid vehicle 20. As shown in Fig. 1, the hybrid vehicle 20 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.

[0011] The engine 22 is configured as a multiple-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 an in-cylinder injection valve 127 that injects fuel supplied from a high-pressure supply pipe 158 of a fuel supply device 150 into a combustion chamber 129, and an ignition plug 130. The in-cylinder injection valve 127 is disposed approximately in the center of the top of the combustion chamber 129 and injects the fuel in a spray form. The ignition plug 130 is disposed near the in-cylinder injection valve 127 so as to be able to ignite the fuel sprayed in a spray form from the in-cylinder injection valve 127.

[0012] In the engine 22, air purified by an air cleaner 122 is drawn into an intake pipe 123, passes through a throttle valve 124 and a surge tank 125, and is further drawn into a combustion chamber 129 via an intake valve 128. Fuel is injected from an in-cylinder injection valve 127 during the intake stroke or compression stroke and ignited by a spark plug 130, causing an explosive combustion of the air-fuel mixture. The reciprocating motion of a piston 132, which is pushed down within the cylinder by the energy of the explosive combustion, is converted into the rotational motion of the crankshaft 23. Exhaust gas discharged from the combustion chamber 129 into an exhaust pipe 134 via an exhaust valve 133 is then discharged into the outside air via a purification device 135. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components in the exhaust, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

[0013] Fuel supply device 150 supplies fuel in fuel tank 151 to direct injection valve 127. Fuel supply device 150 includes fuel tank 151, feed pump 152, low-pressure supply pipe 153, check valve 154, high-pressure pump 157, and high-pressure supply pipe 158. Feed pump 152 is configured as an electric pump that operates by receiving power from low-voltage battery 62, and is disposed in fuel tank 151. Feed pump 152 supplies fuel in fuel tank 151 to low-pressure supply pipe 153. Low-pressure supply pipe 153 is connected to high-pressure pump 157. Check valve 154 is provided in low-pressure supply pipe 153, and allows fuel to flow in a direction from feed pump 152 to high-pressure pump 157, while restricting fuel flow in the opposite direction.

[0014] The high-pressure pump 157 is driven by power from the engine 22 (in this embodiment, by the rotation of the intake camshaft that opens and closes the intake valve 128), and pressurizes fuel in the low-pressure supply pipe 153 and supplies it to the high-pressure supply pipe 158. The high-pressure pump 157 has an electromagnetic valve 157a, a check valve 157b, and a plunger 157c. The electromagnetic valve 157a is connected to the intake port of the high-pressure pump 157 and opens and closes when pressurizing the fuel. The check valve 157b is connected to the discharge port of the high-pressure pump 157 and prevents the backflow of fuel and maintains the fuel pressure in the high-pressure supply pipe 158. The plunger 157c is actuated by the rotation of the engine 22 (the rotation of the intake camshaft) (it moves back and forth in the vertical direction in FIG. 2). When the engine 22 is running, the high-pressure pump 157 draws fuel from the low-pressure supply pipe 153 when the electromagnetic valve 157a is open, and when the electromagnetic valve 157a is closed, the high-pressure pump 157 intermittently supplies fuel compressed by the plunger 157c to the high-pressure supply pipe 158 via the check valve 157b. This causes the fuel supplied to the high-pressure supply pipe 158 to be pressurized.

[0015] The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24. The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The engine ECU 24 receives signals from various sensors via input ports. For example, the engine ECU 24 receives a crank angle θcr from a crank position sensor 140 that detects the rotational position of a 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. The engine ECU 24 also receives cam angles θci and θco from a cam position sensor 144 that detects the rotational position of an intake camshaft that opens and closes intake valves 128 and an exhaust camshaft that opens and closes exhaust valves 133. The engine ECU 24 also receives a throttle opening TH from a throttle position sensor 124a that detects the position of a throttle valve 124. The engine ECU 24 also receives as input an intake air amount Qa from an air flow meter 123a attached to the intake pipe 123 upstream of the throttle valve 124, an intake air temperature Ta from a temperature sensor 123t attached to the intake pipe 123 upstream of the throttle valve 124, and a surge pressure Ps from a pressure sensor 125a attached to the surge tank 125. The engine ECU 24 also receives as input a front air-fuel ratio AF1 from a front air-fuel ratio sensor 137 attached to the exhaust pipe 134 upstream of the purification device 135, and a rear air-fuel ratio AF2 from a rear air-fuel ratio sensor 138 attached to the exhaust pipe 134 downstream of the purification device 135. The engine ECU 24 also receives as input 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, and the high-pressure fuel pressure PH, which is the pressure of the fuel supplied to the in-cylinder injection valve 127, from a fuel pressure sensor 158p attached to the high-pressure supply pipe 158 near the in-cylinder injection valve 127 (for example, a high-pressure delivery pipe).

[0016] The engine ECU 24 outputs various control signals via an output port. For example, the engine ECU 24 outputs control signals to the throttle valve 124, the in-cylinder injection valve 127, the spark plug 130, the feed pump 152, and the high-pressure pump 157 (electromagnetic valve 157a). The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne and the load factor KL. The rotation speed Ne is calculated based on the crank angle θcr of the engine 22. The load factor KL is defined as the ratio of the volume of air actually taken in during one cycle to the stroke volume per cycle of the engine 22. The load factor KL is calculated based on the intake air amount Qa and the rotation speed Ne.

[0017] As shown in FIG. 1, a starter motor 25 for cranking the engine 22 is connected to a 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. The motor 30 is configured as a synchronous generator motor. A rotating shaft 31 to which a rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0 and is also connected to an input shaft 41 of an automatic transmission 40. The inverter 32 is used to drive the motor 30 and is connected to the 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.

[0018] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30. 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 power transmission. The torque converter 43 transmits the power of an input shaft 41 connected to the rotating shaft 31 of the motor 30 to an intermediate shaft 44, which is the input shaft of the automatic transmission 45, with or without amplifying the torque. The automatic transmission 45 has an intermediate shaft 44, an output shaft 42, multiple planetary gears, and multiple hydraulically driven friction engagement elements (clutches and brakes). The output shaft 42 is connected to drive wheels 49 via a differential gear 48. The automatic transmission 45 forms 1st to 6th forward speeds and reverse speeds by engaging and disengaging a plurality of friction engagement elements, and transmits power between the intermediate shaft 44 and the output shaft 42.

[0019] 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. DC / DC converter 64 is connected to high-voltage power line 61 and low-voltage power line 63, and steps down the power on high-voltage power line 61 and supplies the power to low-voltage power line 63.

[0020] The HVECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The HVECU 70 receives signals from various sensors. For example, the HVECU 70 receives 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, a rotation speed Nin from a rotation speed sensor 41a attached to the input shaft 41, a rotation speed Nmi from a rotation speed sensor 44a attached to the intermediate shaft 44, and a rotation speed Nout from a rotation speed sensor 42a attached to the output shaft 42. The HVECU 70 receives a voltage Vbh from a voltage sensor 60v attached between the terminals of the high-voltage battery 60, a current Ibh from a current sensor 60i attached to the output terminal of the high-voltage battery 60, and a voltage Vbl from a voltage sensor 62v attached between the terminals of the low-voltage battery 62. The HVECU 70 receives as input 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 sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake position BP from a brake pedal sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87.

[0021] The HVECU 70 outputs various control signals via an output port. For example, the HVECU 70 outputs control signals to the starter motor 25, the inverter 32, the clutch K0, the automatic transmission 40, and the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 via a communication port. The HVECU 70 calculates the rotation speed Nm of the motor 30 and the power storage rate SOCh of the high-voltage battery 60. The rotation speed Nm is calculated based on the rotation position θm of the rotor (rotating shaft 31) of the motor 30. The power storage rate SOCh is calculated based on the integrated value of the current Ibh of the high-voltage battery 60.

[0022] In the hybrid vehicle 20 of this embodiment, the engine 22, the clutch K0, the motor 30, and the automatic transmission 40 are controlled by cooperative control between the HVECU 70 and the engine ECU 24 so that the vehicle travels in a hybrid driving mode (HV driving mode) or an electric driving mode (EV driving mode). 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.

[0023] It is believed that when the tip temperature Ttp of the direct injection valve 127 is below a threshold value Ttpref (e.g., approximately 150°C) during operation of the engine 22, mainly thermoplastic deposits adhere and accumulate near the tip of the direct injection valve 127, and when the tip temperature Ttp is equal to or higher than the threshold value Ttpref, mainly thermosetting deposits adhere and accumulate near the tip of the direct injection valve 127. The tip temperature Ttp of the direct injection valve 127 is estimated, for example, by applying the intake air amount Qa and the coolant temperature Tw to a tip temperature estimation map. The tip temperature estimation map is determined in advance through experiments, analysis, and machine learning as the relationship between the intake air amount Qa, the coolant temperature Tw, and the tip temperature Ttp. The tip temperature Ttp of the direct injection valve 127 is estimated to be higher as the intake air amount Qa increases and as the coolant temperature Tw increases.

[0024] Thermoplastic deposits are removed by injecting fuel from in-cylinder injection valve 127 when high fuel pressure PH is equal to or greater than fuel pressure PHhi1. That is, fuel pressure PHhi1 is set within a range equal to or greater than the lower limit fuel pressure at which thermoplastic deposits adhering near the tip of in-cylinder injection valve 127 can be removed by fuel injection from in-cylinder injection valve 127, and is, for example, approximately 10 MPa to 14 MPa. A request for removal of thermoplastic deposits is made from when counter C1 reaches or exceeds threshold value Cref11 until it falls below a smaller threshold value Cref12 (for example, the value 0). Counter C1 is a counter that reflects the amount of thermoplastic deposits adhering near the tip of in-cylinder injection valve 127. For example, counter C1 counts up each time fuel is injected when engine 22 coolant temperature Tw is equal to or higher than threshold value Twref (e.g., approximately 60°C to 80°C), high-pressure fuel pressure PH is lower than fuel pressure PHhi1, and tip temperature Ttp of direct injection valve 127 is lower than threshold value Ttpref, and counter C1 counts down each time fuel is injected when high-pressure fuel pressure PH is equal to or higher than fuel pressure PHhi1. The count-up amount of counter C1 is set to increase as the high-pressure fuel pressure PH decreases. This is because deposits are more likely to adhere and accumulate on direct injection valve 127 as the high-pressure fuel pressure PH decreases.

[0025] Thermosetting deposits are removed by injecting fuel from direct injection valve 127 when the high fuel pressure PH is equal to or greater than fuel pressure PHhi2, which is somewhat higher than fuel pressure PHhi1. That is, fuel pressure PHhi2 is set within a range equal to or greater than the lower limit fuel pressure at which thermosetting deposits adhering near the tip of direct injection valve 127 can be removed by fuel injection from direct injection valve 127; for example, a pressure of approximately 18 MPa to 22 MPa is used. A request for removal of thermosetting deposits is made from when counter C2 reaches or exceeds threshold value Cref21 until it falls below a smaller threshold value Cref22 (for example, the value 0). Counter C2 reflects the amount of thermosetting deposits adhering near the tip of direct injection valve 127. For example, counter C2 counts up each time fuel is injected when engine 22 coolant temperature Tw is equal to or higher than threshold value Twref, high-pressure fuel pressure PH is less than fuel pressure PHhi2, and tip temperature Ttp of direct injection valve 127 is equal to or higher than threshold value Ttpref, and counts down each time fuel is injected when high-pressure fuel pressure PH is equal to or higher than fuel pressure PHhi2. Similar to counter C1, the count-up amount of counter C2 is set to increase as the high-pressure fuel pressure PH decreases.

[0026] Next, adjustment of the high fuel pressure PH when the vehicle is stopped, the engine 22 is running, and removal of thermoplastic and / or thermosetting deposits is required will be described. FIG. 3 is a flowchart showing an example of a fuel pressure control routine executed by the engine ECU 24. This routine is repeatedly executed when the vehicle is stopped and the engine 22 is running. Note that when the vehicle is stopped and forced charging of the high-voltage battery 60 is required, the engine 22 is operated under load to output a certain amount of power, and power from the engine 22 is used to generate electricity for the motor 30, which then charges the high-voltage battery 60. A request for forced charging of the high-voltage battery 60 is made when the charge storage rate SOCh of the high-voltage battery 60 is less than the threshold value Sref. When the vehicle is stopped, forced charging of the high-voltage battery 60 is not required, and warming up of the engine 22 or heating of the vehicle cabin is required, the engine 22 is idled.

[0027] 3, the engine ECU 24 determines whether removal of thermoplastic and / or thermosetting deposits is required (step S100). The engine ECU 24 also determines whether forced charging of the high-voltage battery 60 is being performed (steps S110 and S140). The process of step S100 is performed using the counters C1 and C2 described above. The processes of steps S110 and S140 determine whether the engine 22 is operating under load so as to output a certain amount of power or is idling.

[0028] If it is determined in step S100 that removal of neither thermoplastic nor thermosetting deposits is required and if it is determined in step S110 that forced charging of the high-voltage battery 60 is not being performed, the engine ECU 24 executes the processes of steps S120 and S170. Specifically, the engine ECU 24 sets the target fuel pressure PH* to a relatively low fuel pressure PHlo0 (step S120) and controls the high-pressure pump 157 (solenoid valve 157a) so that the high-pressure fuel pressure PH becomes the target fuel pressure PH* (step S170). This routine ends. When forced charging of the high-voltage battery 60 is not being performed, the engine 22 is idling, so the high-pressure fuel pressure PH is set relatively low.

[0029] If it is determined in step S100 that removal of neither thermoplastic nor thermosetting deposits is required and it is determined in step S110 that the high-voltage battery 60 is being forcibly charged, the engine ECU 24 executes the processes of steps S130 and S170. Specifically, the engine ECU 24 sets the target fuel pressure PH* to a fuel pressure PHhi0 that is sufficiently higher than the fuel pressure PHlo0 (step S130), and controls the high-pressure pump 157 (solenoid valve 157a) so that the high-pressure fuel pressure PH becomes the target fuel pressure PH* (step S170). This routine ends. When the high-voltage battery 60 is being forcibly charged, the engine 22 is operated under load to output a certain amount of power, and therefore the high-pressure fuel pressure PH is set relatively high.

[0030] When it is determined in step S100 that removal of thermoplastic and / or thermosetting deposits is requested and when it is determined in step S140 that forced charging of the high-voltage battery 60 is being performed, the engine ECU 24 executes the processes of steps S150 and S170. Specifically, the engine ECU 24 sets the target fuel pressure PH* to one of the fuel pressures PHhi1 and PHhi2, which is sufficiently higher than the fuel pressure PHlo0 (step S150), and controls the high-pressure pump 157 (solenoid valve 157a) so that the high-pressure fuel pressure PH becomes the target fuel pressure PH* (step S170). This routine ends. In this embodiment, when removal of only thermoplastic deposits is requested, the target fuel pressure PH* is set to fuel pressure PH1*. When removal of only thermosetting deposits or removal of both thermoplastic and thermosetting deposits is requested, the target fuel pressure PH* is set to fuel pressure PH2*. Therefore, the high fuel pressure PH becomes either the fuel pressure PHhi1 or PHhi2, and the fuel injected from the direct injection valve 127 removes thermoplastic and / or thermosetting deposits.

[0031] When step S100 determines that removal of thermoplastic and / or thermosetting deposits is required and step S140 determines that forced charging of the high-voltage battery 60 is not being performed, the engine ECU 24 executes steps S160 and S170. Specifically, the engine ECU 24 sets the target fuel pressure PH* to fuel pressure PHlo1, which is higher than fuel pressure PHlo0 but lower than fuel pressures PHhi1 and PHhi2 (step S160), and controls the high-pressure pump 157 (solenoid valve 157a) so that the high-pressure fuel pressure PH becomes the target fuel pressure PH* (step S170). This routine ends. Therefore, when the engine 22 is idling, the high-pressure fuel pressure PH becomes fuel pressure PHlo1, which suppresses an increase in the amount of thermoplastic and / or thermosetting deposits adhering to the vicinity of the tip of the direct injection valve 127 compared to when the high-pressure fuel pressure PH becomes fuel pressure PHlo0. This is based on the fact that the lower the high-pressure fuel pressure PH, the more easily thermoplastic and thermosetting deposits adhere and accumulate on the direct injection valve 127. The fuel pressure PHlo1 is set within a range equal to or higher than the lower limit fuel pressure at which an increase in the amount of thermoplastic and thermosetting deposits can be suppressed to some extent, and equal to or lower than the upper limit fuel pressure at which the minimum injection quantity Qmin that can be injected from the direct injection valve 127 is equal to or lower than the idle injection quantity Qid required for idling the engine 22; for example, a range of approximately 3.5 MPa to 4.5 MPa is used. The minimum injection quantity Qmin increases as the high-pressure fuel pressure PH increases.

[0032] As described above, thermoplastic deposits are removed by injecting fuel from the in-cylinder injection valve 127 when the high-pressure fuel pressure PH is equal to or greater than the fuel pressure PHhi1, and thermosetting deposits are removed by injecting fuel from the in-cylinder injection valve 127 when the high-pressure fuel pressure PH is equal to or greater than the fuel pressure PHhi2. Consider the case where, while the vehicle is stopped, the high-voltage battery 60 is not being forcibly charged (when the engine 22 is operating under load to output a certain amount of power) but is not being forcibly charged (when the engine 22 is idling). When fuel is injected from the in-cylinder injection valve 127 when the high-pressure fuel pressure PH is equal to or greater than either the fuel pressure PHhi1 or PHhi2, the minimum injection amount Qmin that can be injected from the in-cylinder injection valve 127 may be greater than the idle injection amount Qid required for idling the engine 22. In this case, fuel injection of the minimum injection amount Qmin is performed from the direct injection valve 127, which is excessive relative to the idle injection amount Qid. Therefore, if the intake air amount Qa is not adjusted, the air-fuel ratio may become rich, which may result in a deterioration in emissions. Furthermore, if the intake air amount Qa is adjusted, unexpected torque output or revving up of the engine 22 may occur. Therefore, in this embodiment, when the hybrid vehicle 20 is stopped, thermoplastic and / or thermosetting deposit removal is required, and the high-voltage battery 60 is being forcibly charged (when the engine 22 is operating under load to output a certain amount of power), the high-pressure fuel pressure PH is set to either fuel pressure PHhi1 or PHhi2. This prevents the minimum injection amount Qmin from becoming greater than the required injection amount Qf* required of the direct injection valve 127, thereby preventing problems such as a deterioration in emissions. In other words, when the high pressure fuel pressure PH is fuel pressure PHhi1 or fuel pressure PHhi2, the required output of the engine 22 (required charging power Pch* of the high-voltage battery 60) is set so that the minimum injection amount Qmin is equal to or less than the required injection amount Qf* of the direct injection valve 127 based on the required output of the engine 22. The required charging power Pch* may be the same when the high pressure fuel pressure PH is fuel pressure PHhi1 and when the high pressure fuel pressure PH is fuel pressure PHhi2, or may be different.Furthermore, when hybrid vehicle 20 is stopped, thermoplastic and / or thermosetting deposit removal is required, and high-voltage battery 60 is not being forcibly charged (engine 22 is idling), high fuel pressure PH is set to fuel pressure PHlo1. This prevents hybrid vehicle 20 from having minimum injection quantity Qmin exceed idle injection quantity Qid, thereby preventing problems such as worsening of emissions.

[0033] In the present embodiment described above, when the hybrid vehicle 20 is stopped, when removal of thermoplastic and / or thermosetting deposits is not required, and when the high-voltage battery 60 is not being forcibly charged (the engine 22 is idling), the high-pressure fuel pressure PH is set to fuel pressure PHlo0 (first fuel pressure). Furthermore, when the hybrid vehicle 20 is stopped, when removal of thermoplastic and / or thermosetting deposits is required, and when the high-voltage battery 60 is being forcibly charged (the engine 22 is being operated under load so as to output a certain amount of power), the high-pressure fuel pressure PH is set to either fuel pressure PHhi1 or PHhi2 (second fuel pressure). This enables the hybrid vehicle 20 to remove thermoplastic and / or thermosetting deposits. Furthermore, when the hybrid vehicle 20 is stopped, when removal of thermoplastic and / or thermosetting deposits is required, and when the high-voltage battery 60 is not being forcibly charged (the engine 22 is idling), the high-pressure fuel pressure PH is set to fuel pressure PHlo1 (third fuel pressure). As a result, hybrid vehicle 20 can suppress an increase in the amount of thermoplastic or thermosetting deposits that adhere to the vicinity of the tip of in-cylinder injection valve 127, compared to when high pressure fuel pressure PH is set to fuel pressure PHlo0. Also, hybrid vehicle 20 can suppress the occurrence of problems such as a deterioration in emissions, compared to when high pressure fuel pressure PH is set to either fuel pressure PHhi1 or PHhi2.

[0034] In the above-described embodiment, when the hybrid vehicle 20 is stopped, when removal of thermoplastic and / or thermosetting deposits is required, and when the high-voltage battery 60 is being forcibly charged (when the engine 22 is being operated under load so as to output a certain amount of power), the high-pressure fuel pressure PH is set to one of the fuel pressures PHhi1 and PHhi2. This enables the hybrid vehicle 20 to remove thermoplastic and / or thermosetting deposits. Similarly, when the hybrid vehicle 20 is running, when removal of thermoplastic and / or thermosetting deposits is required, and when the high-voltage battery 60 is being forcibly charged, the high-pressure fuel pressure PH may also be set to one of the fuel pressures PHhi1 and PHhi2.

[0035] In the above-described embodiment, when hybrid vehicle 20 is stopped, when removal of thermoplastic and / or thermosetting deposits is required, and when forced charging of high-voltage battery 60 is not being performed (engine 22 is idling), high-pressure fuel pressure PH is set to fuel pressure PHlo1. This allows hybrid vehicle 20 to suppress an increase in the amount of thermoplastic and / or thermosetting deposits adhering to the tip of in-cylinder injection valve 127, compared to when high-pressure fuel pressure PH is set to fuel pressure PHlo0. When hybrid vehicle 20 is traveling, when removal of thermoplastic and / or thermosetting deposits is required, and when forced charging of high-voltage battery 60 is not being performed, high-pressure fuel pressure PH may be set to a fuel pressure within a range equal to or greater than fuel pressure PHlo1, based on required injection amount Qf* of in-cylinder injection valve 127, which is based on the required output of engine 22, which is based on the required output for traveling.

[0036] In the above-described embodiment, in the engine 22, the in-cylinder injection valve 127 is disposed approximately at the center of the top of the combustion chamber 129, and the spark plug 130 is disposed near the in-cylinder injection valve 127. However, the in-cylinder injection valve 127 may be disposed on the side of the combustion chamber 129, and the spark plug 130 may be disposed approximately at the center of the top of the combustion chamber 129.

[0037] In the above-described embodiment, the engine 22 includes the in-cylinder injection valve 127. However, in addition to the in-cylinder injection valve 127, the engine 22 may further include an intake injection valve that injects fuel supplied from the low-pressure supply pipe 153 of the fuel supply device 150 into the intake port.

[0038] In the above-described embodiment, the hybrid vehicle 20 includes the engine ECU 24 and the HVECU 70. However, the engine ECU 24 and the HVECU 70 may be integrated into one unit.

[0039] In the above-described embodiment, the hybrid vehicle 20 includes the engine 22, the motor 30 connected to the engine 22 via the clutch K0, and the automatic transmission 40 connected to the motor 30 and the drive wheels 49. However, the hybrid vehicle is not limited to this, and may include an engine, a motor capable of generating electricity using power from the engine and outputting power for running, and a power storage device that exchanges power with the motor.

[0040] In the hybrid vehicle of the present disclosure, the control device may idle the engine when the engine is operating and the power storage device is not being forcibly charged, and the second fuel pressure may be set within a range such that a minimum injection amount that can be injected from the in-cylinder injection valve is equal to or less than an idle injection amount required for the engine to idle.

[0041] 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 described 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 and the engine ECU 24 correspond to the "control device."

[0042] The above describes the forms for implementing the present disclosure, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0043] The present disclosure is applicable to the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0044] 20 Hybrid vehicle, 22 Engine, 24 Engine ECU, 30 Motor, 32 Inverter, 60 High voltage battery, 70 HVECU, 127 Direct injection valve, 150 Fuel supply system.

Claims

[Claim 1] A hybrid vehicle including an engine having an in-cylinder injection valve, a fuel supply device that supplies fuel to the in-cylinder injection valve, a motor that is capable of generating electricity using power from the engine and outputting power for running, an electricity storage device that exchanges electric power with the motor, and a control device that controls the engine, the fuel supply device, and the motor, The control device when the vehicle is stopped, when removal of deposits adhering to the direct injection valve is not required, and when forced charging of the power storage device involving load operation of the engine is not being performed, controlling the fuel supply device so that a supply fuel pressure, which is a pressure of fuel supplied to the direct injection valve, becomes a first fuel pressure; when the vehicle is stopped, when the deposit removal is requested, and when the power storage device is being forcibly charged, the fuel supply device is controlled so that the supplied fuel pressure becomes a second fuel pressure higher than the first fuel pressure; when the vehicle is stopped, when deposit removal is required, and when forced charging of the power storage device is not being performed, the fuel supply device is controlled so that the supplied fuel pressure becomes a third fuel pressure that is higher than the first fuel pressure and lower than the second fuel pressure; Hybrid car.

Images