JP2016155404A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle including an engine that has a port injection valve through which fuel is injected into an intake passage, and prevent degradation in durability of parts of a fuel pipe system.SOLUTION: An engine ECU 141 controls the output power of an engine 10 according to the sum of traveling power, which is required for a vehicle to travel, and charging/discharging power of a power storage device for use in controlling the SOC of the power storage device, and controls a feed pump 512 so that the pressure of fuel accumulated in a low-pressure delivery pipe 53 becomes a target fuel pressure. When a decision is made that the target rotating speed of the engine 10 determined with an operating point at which the power required for the engine 10 is outputted falls within a resonant range within which a resonance phenomenon occurs in the low-pressure delivery pipe 53, the engine ECU 141 changes the operating point of the engine 10 along a fuel economy optimal operation line or equal power line so that the target rotating speed falls outside the resonant range.SELECTED DRAWING: Figure 2

Description

  The present invention relates to control of a hybrid vehicle including an engine including a port injection valve that injects fuel into an intake passage.

  Japanese Patent Application Laid-Open No. 2013-68127 (Patent Document 1) is applied to an engine including a fuel pump and a fuel pressure sensor for detecting a supply pressure of fuel to a port injection valve by the fuel pump, and a detected value of the fuel pressure sensor. A control device for controlling the operation amount of the fuel pump according to the above is disclosed. In order to diagnose the fuel pressure sensor, this control device changes the operation amount of the fuel pump in the direction of increasing the supply pressure, and determines whether there is a failure in the fuel pressure sensor based on the detected value of the fuel pressure sensor at this time To do.

  In the failure diagnosis of the fuel pressure sensor, the fuel pressure is increased to the valve opening pressure of the relief valve by increasing the drive duty of the fuel pump to the duty for diagnosis. When the fuel pressure sensor at this time does not detect the vicinity of the valve opening pressure, it is determined that the fuel pressure sensor is abnormal.

JP 2013-68127 A

  However, as a result of experiments by the present inventors, it has been found that when the fuel pressure is increased to a diagnostic fuel pressure, a phenomenon occurs in which the detected value of the fuel pressure sensor is not stable depending on the rotational speed of the engine. And when this phenomenon generate | occur | produced, since a stress acts with respect to the components which comprise a fuel pressure piping system by a remarkable pulsating component being superimposed on a fuel pressure, it turned out that the durability of the said component falls.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a fuel piping system in a hybrid vehicle having an engine including a port injection valve for injecting fuel into an intake passage. This is to prevent a decrease in durability of the parts.

  In one aspect of the present invention, a hybrid vehicle includes an engine, an electric storage device, an electric motor that generates vehicle driving force by electric power from the electric storage device, a fuel supply device that supplies fuel to the engine, an engine, an electric motor, and a fuel supply And a control device for controlling the device. The fuel supply device includes a storage unit that stores fuel to be injected into the intake passage, a feed pump that pressurizes the fuel and supplies the fuel to the storage unit, a high-pressure storage unit that stores fuel to be injected into the cylinder, A high-pressure pump that is driven according to the rotation of the engine and pressurizes the fuel to supply the fuel to the high-pressure reservoir. The pressure of the fuel stored in the storage part is set lower than the pressure of the fuel stored in the high-pressure storage part. The control device controls the output power of the engine according to the sum of the travel power required for vehicle travel and the charge / discharge power of the power storage device for controlling the SOC of the power storage device, and the pressure of the fuel stored in the storage unit Is configured to control the feed pump such that the fuel pressure reaches the target fuel pressure. When it is determined that the target rotational speed of the engine determined by the operating point for outputting the power required for the engine is within a resonance range in which a resonance phenomenon can occur in the reservoir, the target rotational speed is determined. Change the engine operating point on the optimal operating line set in advance according to the efficiency of the engine so that the speed is out of the resonance range, or on the equal power line that is a set of operating points with the same engine output power To do.

  According to the hybrid vehicle described above, since the engine rotational speed is changed outside the resonance range by changing the target operating point of the engine, resonance occurring in the low-pressure fuel piping system can be suppressed. Thereby, since the pulsation of the fuel pressure in the low-pressure fuel piping system is reduced, it is possible to prevent the durability of the parts from being lowered.

  According to the present invention, in a hybrid vehicle including an engine including a port injection valve that injects fuel into the intake passage, it is possible to prevent a decrease in durability of components of the fuel piping system.

It is a block diagram which shows the structure of the hybrid vehicle to which this invention is applied. It is the figure which showed the structure of the engine and fuel supply apparatus regarding fuel supply. It is the wave form diagram which showed an example of the fuel pressure change at the time of stack detection processing being performed. It is the wave form diagram which expanded a part of change of the actual fuel pressure shown by FIG. It is the schematic diagram which showed the path | route from a fuel tank to a high pressure delivery pipe and a low pressure delivery pipe. It is a figure for demonstrating the relationship between the amplitude of fuel pressure pulsation, and target fuel pressure. It is a figure for demonstrating the relationship between the internal volume change rate by the elastic deformation of a pulsation damper, the amplitude of a fuel pressure pulsation, and a target fuel pressure. It is a figure for demonstrating the relationship between a fuel pressure pulsation and an engine speed. It is a figure for demonstrating control of the engine speed in this Embodiment. It is a collinear diagram which showed the rotational speed of each rotation element of a power split device. It is a flowchart for demonstrating the change method of the engine speed which concerns on this Embodiment. It is a flowchart for demonstrating the change method of the engine speed which concerns on this Embodiment. It is a flowchart for demonstrating the detail of the process of FIG.12 S15. It is a figure for demonstrating control of an engine speed in the modification of this Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

(Description of basic configuration)
FIG. 1 is a block diagram showing a configuration of a hybrid vehicle 1 to which the present invention is applied. Referring to FIG. 1, hybrid vehicle 1 includes an engine 10, a fuel supply device 15, motor generators 20 and 30, a power split mechanism 40, a reduction mechanism 58, drive wheels 62, a power control unit (PCU). ) 60, a battery (power storage device) 70, and a control device 100.

  The hybrid vehicle 1 is a series / parallel type hybrid vehicle, and is configured to be able to travel using at least one of the engine 10 and the motor generator 30 as a drive source.

  Engine 10, motor generator 20, and motor generator 30 are connected to each other via power split mechanism 40. A reduction mechanism 58 is connected to the rotating shaft 16 of the motor generator 30 coupled to the power split mechanism 40. The rotating shaft 16 is connected to the drive wheel 62 via the reduction mechanism 58 and is connected to the crankshaft of the engine 10 via the power split mechanism 40.

  The power split mechanism 40 can split the driving force of the engine 10 into the motor generator 20 and the rotating shaft 16. The motor generator 20 can function as a starter for starting the engine 10 by rotating the crankshaft of the engine 10 via the power split mechanism 40. The power split mechanism 40 is constituted by, for example, a planetary gear mechanism. In this case, the rotating shaft of the motor generator 20 is connected to the sun gear SG of the planetary gear mechanism, the crankshaft of the engine 10 is connected to the carrier CA, and the rotating shaft 16 of the motor generator 30 and the reduction mechanism are connected to the ring gear RG. The drive wheel 62 is connected via 58.

  Motor generators 20 and 30 are both well-known synchronous generator motors that can operate as both a generator and a motor. That is, motor generator 20 can constitute a “power generation mechanism” that generates charging power for battery 70 using the output of engine 10 transmitted via power split mechanism 40. Further, a mechanism for generating a vehicle driving force can be realized by the motor generator 30 operating as an “electric motor” by the electric power from the battery 70. Motor generators 20 and 30 are connected to PCU 60, and PCU 60 is connected to battery 70.

  The control device 100 includes a power management electronic control unit (hereinafter referred to as PM-ECU) 140, an engine electronic control unit (hereinafter referred to as engine ECU) 141, and a motor electronic control unit (hereinafter referred to as motor). ECU) 142 and a battery electronic control unit (hereinafter referred to as battery ECU) 143.

  PM-ECU 140 is connected to engine ECU 141, motor ECU 142, and battery ECU 143 via a communication port (not shown). PM-ECU 140 exchanges various control signals and data with engine ECU 141, motor ECU 142, and battery ECU 143.

  Motor ECU 142 is connected to PCU 60 and controls driving of motor generators 20 and 30. The battery ECU 143 calculates a remaining capacity (hereinafter referred to as SOC (State of charge)) based on the integrated value of the charge / discharge current of the battery 70.

  The engine ECU 141 is connected to the engine 10 and the fuel supply device 15. The engine ECU 141 receives signals from various sensors that detect the operating state of the engine 10 and performs operation control such as fuel injection control, ignition control, and intake air amount adjustment control in accordance with the input signals. Further, the engine ECU 141 controls the fuel supply device 15 to supply fuel to the engine 10.

  In the hybrid vehicle 1 having the above configuration, the configuration and control of the engine 10 and the fuel supply device 15 will be described in more detail.

  FIG. 2 is a diagram showing the configuration of the engine 10 and the fuel supply device 15 relating to fuel supply. In the present embodiment, a vehicle to which the present invention is applied is a hybrid vehicle that employs a dual injection type internal combustion engine that uses both in-cylinder injection and port injection as an internal combustion engine, for example, an in-line 4-cylinder gasoline engine.

  Referring to FIG. 2, engine 10 includes an intake manifold 36, an intake port 21, and four cylinders 11 provided in the cylinder block.

  The intake air AIR flows into each cylinder 11 from the intake pipe through the intake manifold 36 and the intake port 21 when a piston (not shown) in the cylinder 11 descends.

  The fuel supply device 15 includes a low pressure fuel supply mechanism 50 and a high pressure fuel supply mechanism 80. The low-pressure fuel supply mechanism 50 includes a fuel pump 51, a low-pressure fuel pipe 52, a low-pressure delivery pipe 53, a low-pressure fuel pressure sensor 53a, and a port injection valve 54. The low-pressure delivery pipe 53 is a “reservoir” that stores fuel to be injected from the port injection valve 54.

  The high pressure fuel supply mechanism 80 includes a high pressure pump 81, a check valve 82a, a high pressure fuel pipe 82, a high pressure delivery pipe 83, a high pressure fuel pressure sensor 83a, and an in-cylinder injection valve 84. The high-pressure delivery pipe 83 is a “high-pressure reservoir” that stores fuel to be injected from the in-cylinder injection valve 84.

  The in-cylinder injection valve 84 is an in-cylinder injection injector that exposes the injection hole portion 84 a in the combustion chamber of each cylinder 11. When the in-cylinder injection valve 84 opens, the pressurized fuel in the high-pressure delivery pipe 83 is injected into the combustion chamber 16 from the injection hole portion 84a of the in-cylinder injection valve 84.

  The high pressure pump 81 is connected between the low pressure fuel pipe 52 and the high pressure fuel pipe 82. The check valve 82a prevents the back flow of fuel from the high pressure fuel pipe 82 to the high pressure pump 81.

  The high pressure pump 81 includes an upstream pipe 90, a downstream pipe 91, a pulsation damper 92, a high pressure pump main body 93, and an electromagnetic spill valve 94. An upstream pipe 90 of the high pressure pump 81 is connected to a low pressure fuel pipe 52 a branched from the low pressure fuel pipe 52, and a downstream pipe 91 is connected to a high pressure fuel pipe 82.

  The pulsation damper 92 is provided in the upstream pipe 90 and includes an elastic diaphragm that receives fuel pressure and a compression coil spring. The pulsation damper 92 is configured to change the internal volume by elastic deformation of the diaphragm and suppress the pressure pulsation of the fuel in the upstream pipe 90.

  In the high-pressure pump main body 93, the pressurizing chamber 931 a changes its volume by the reciprocating movement of the plunger 932. The electromagnetic spill valve 94 allows the intake of fuel into the pressurizing chamber 931a and the delivery of the fuel in the pressurizing chamber 931a to the low pressure fuel pipe 52 according to the displacement of the plunger 932 when opening, and closes the valve. It functions as a check valve.

  The follower lifter 934 slides the plunger 932 by being pressed by the cam 933a. The return spring 935 includes a compression coil spring provided between the pump housing 931 and the follower lifter 934, and biases the follower lifter 934 toward the cam 933a.

  The camshaft 933 is provided at one end of the exhaust camshaft of the engine 10 and has a cam 933a at the end. Since the camshaft 933 is always rotating while the engine 10 is being driven, the high-pressure pump main body 93 operates in conjunction with the driving of the engine 10.

  The high-pressure delivery pipe 83 is connected to the high-pressure fuel pipe 82 at one end side of the cylinder 11 in the series arrangement direction. An in-cylinder injection valve 84 is connected to the high pressure delivery pipe 83. A high-pressure fuel pressure sensor 83 a that detects the internal fuel pressure is attached to the high-pressure delivery pipe 83.

  The engine ECU 141 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input interface circuit, an output interface circuit, and the like. The engine ECU 141 receives an engine start / stop command from the PM-ECU of FIG. 1 and controls the engine 10 and the fuel supply device 15.

  The engine ECU 141 calculates the fuel injection amount necessary for each combustion based on the accelerator opening, the intake air amount, the engine speed, and the like. Further, the engine ECU 141 outputs an injection command signal to the port injection valve 54 and the in-cylinder injection valve 84 in a timely manner based on the calculated fuel injection amount.

  The engine ECU 141 first performs fuel injection by the port injection valve 54 when the engine 10 is started. The ECU 140 starts outputting an injection command signal to the in-cylinder injection valve 84 when the fuel pressure in the high-pressure delivery pipe 83 detected by the high-pressure fuel pressure sensor 83a exceeds a preset pressure value.

  Further, the engine ECU 141 is based on in-cylinder injection from the in-cylinder injection valve 84, for example, and the mixture formation is insufficient in in-cylinder injection such as when the engine 10 is warmed up or when the engine is under a low rotation and high load. Under certain operating conditions, port injection is used together. Or engine ECU141 performs port injection from port injection valve 54 at the time of the high rotation high load in which port injection is effective, etc., for example based on in-cylinder injection from in-cylinder injection valve 84.

  In the present embodiment, the fuel supply device 15 is characterized in that the pressure of the low-pressure fuel supply mechanism 50 can be variably controlled. Hereinafter, the low pressure fuel supply mechanism 50 of the fuel supply device 15 will be described in more detail.

  The fuel pumping unit 51 includes a fuel tank 511, a feed pump 512, a suction filter 513, a fuel filter 514, a relief valve 515, and a fuel pipe 516 connecting them.

  The fuel tank 511 stores fuel consumed by the engine 10, for example, gasoline. The suction filter 513 prevents inhalation of foreign matter. The fuel filter 514 removes foreign matters in the discharged fuel.

  The relief valve 515 opens when the pressure of the fuel discharged from the feed pump 512 reaches the upper limit pressure, and maintains the closed state while the fuel pressure does not reach the upper limit pressure.

  The low-pressure fuel pipe 52 connects the fuel pump 51 to the low-pressure delivery pipe 53. However, the low-pressure fuel pipe 52 is not limited to the fuel pipe, and may be a single member through which the fuel passage is formed or a plurality of members through which the fuel passage is formed.

  The low-pressure delivery pipe 53 is connected to the low-pressure fuel pipe 52 on one end side of the cylinder 11 in the series arrangement direction. A port injection valve 54 is connected to the low pressure delivery pipe 53. The low pressure delivery pipe 53 is equipped with a low pressure fuel pressure sensor 53a for detecting the internal fuel pressure.

  The port injection valve 54 is a port injection injector that exposes the injection hole portion 54 a in the intake port 21 corresponding to each cylinder 11. When the port injection valve 54 opens, the pressurized fuel in the low pressure delivery pipe 53 is injected into the intake port 21 from the injection hole portion 54a of the port injection valve 54.

  Feed pump 512 is driven and stopped based on a command signal transmitted from engine ECU 141.

The feed pump 512 is capable of pumping fuel from the fuel tank 511 and pressurizing and discharging the pumped fuel to a pressure within a constant variable range of, for example, less than 1 [MPa: megapascal]. Furthermore, the feed pump 512 can change the discharge amount [m ³ / sec] and the discharge pressure [kPa: kilopascals] per unit time under the control of the engine ECU 141.

  Controlling the feed pump 512 in this way is preferable in the following points. First, the low pressure delivery pipe 53 needs to be pressurized to the extent that it does not vaporize in order to prevent the internal fuel from vaporizing when the engine becomes hot. However, if the pressure is too high, the load on the pump is large and the energy loss is large. Since the pressure for preventing the vaporization of fuel changes depending on the temperature, energy loss can be reduced by applying the necessary pressure to the low-pressure delivery pipe 53. Further, by appropriately controlling the feed pump 512 so as to send the fuel corresponding to the amount consumed by the engine, it is possible to save energy that is wastedly pressurized. Therefore, it is advantageous in that fuel efficiency is improved compared to a configuration in which the pressure is once increased and then the pressure is made constant by the pressure regulator.

  In the variable fuel pressure control by the feed pump 512, it is necessary to ensure the reliability of the detection value of the low-pressure fuel pressure sensor 53a provided in the low-pressure delivery pipe 53 that stores the fuel that performs port injection. For this reason, the stack detection of the detection value of the low-pressure fuel pressure sensor 53a as described above is periodically performed.

(Description of basic processing of stack detection control)
The stack detection is a failure detection for confirming that the detection value of the low-pressure fuel pressure sensor 53a is not a fixed value. In order to confirm that the detection value of the low-pressure fuel pressure sensor 53a changes, at least the low-pressure fuel pressure sensor 53a. It is necessary to confirm the detected value at two points of pressure.

  In one example, as shown in the waveform of FIG. 3 below, the stack detection is performed by raising the fuel pressure to a pressure higher than that during normal use after starting the engine and then lowering the fuel pressure. FIG. 3 is a waveform diagram showing an example of a change in fuel pressure when the stack detection process is executed.

  Referring to FIG. 3, at time t <b> 1, when engine 10 is in an operating state, an engine stop command is output from PM-ECU 140, and engine ECU 141 stops engine 10 accordingly. Between times t1 and t2, the target fuel pressure P0 of the low pressure delivery pipe 53 is set to 0 [kPa].

  Subsequently, when an engine start command is output from PM-ECU 140 at time t2, in response to this, engine ECU 141 starts operation of engine 10 and sets target fuel pressure P0 in the following order to perform stack detection. Change.

  First, at time t2 to t3, the target fuel pressure P0 is set to PH (for example, 644 [kPa]). PH is set higher than the fuel pressure normally used for detecting the stack of the low-pressure fuel pressure sensor 53a. The fuel pressure sensor detection value A is acquired at the time t3 when the time during which the fuel pressure stabilizes has elapsed.

  Thereafter, at time t4 to t5, the target fuel pressure P0 is set to PL (for example, 400 [kPa]) lower than PH, and the fuel pressure sensor detection value B is acquired at time t5 when the fuel pressure stabilizes.

  When the detected values A and B are ready, the presence or absence of stack failure is diagnosed. Specifically, if the detected value A indicates a value near PH and the detected value B indicates a value near PL, it is determined that the low pressure fuel pressure sensor 53a is normal. On the other hand, if the detection values A and B indicate the same value, it is determined that a stack failure has occurred in the low-pressure fuel pressure sensor 53a.

  At time t1 to t2, the target fuel pressure P0 = 0 [kPa] is set. However, when the engine is stopped, there is no injection from the port injection valve, and the fuel pressure of the low-pressure delivery pipe cannot be lowered. P1 does not follow the target fuel pressure P0. Furthermore, the fuel that is sealed in the low-pressure delivery pipe expands due to heat from the engine, so that the actual fuel pressure P1 may increase. In such a case, if stack detection is performed by changing the target fuel pressure P0 from low pressure to high pressure, stack detection cannot be performed unless the fuel pressure is once lowered. Therefore, as shown in FIG. 3, stack detection can be started at an early stage by changing the target fuel pressure P0 from a high pressure to a low pressure.

(Fuel pressure pulsation in low-pressure fuel piping system)
In the case where stack detection is performed as described above, pulsation is generated in the fuel pressure of the low-pressure delivery pipe 53 when the rotational speed of the engine 10 is within a certain range. FIG. 4 is an enlarged waveform diagram showing a part of the change in the actual fuel pressure P1 shown in FIG. FIG. 4 also shows changes in engine speed.

  Referring to FIG. 4, during the time t2 to t3 when the target fuel pressure P0 is set high, the detected value of the low-pressure fuel pressure sensor 53a is not stable, and significant fluctuation occurs. The fluctuation of the detected value of the fuel pressure sensor appears at times ta to tb when the engine speed is near Ne1 [rpm]. Hereinafter, the reason why the detection value of the fuel pressure sensor fluctuates will be described.

  FIG. 5 is a schematic diagram showing paths from the fuel tank 511 to the high pressure delivery pipe 83 and the low pressure delivery pipe 53. Referring to FIG. 5, low pressure fuel pipe 52 extends toward low pressure delivery pipe 53 and low pressure fuel pipe 52 a extends toward high pressure delivery pipe 83 from feed pump 512 in fuel tank 511. A high pressure pump 81 is provided at the end of the low pressure fuel pipe 52a on the high pressure delivery pipe 83 side.

  The feed pump 512 is an electric pump that is driven by an electric motor controlled by the engine ECU 141 and can change the fuel pressure. On the other hand, the high-pressure pump 81 is a mechanical pump that is driven according to the rotation of the engine 10.

  The high-pressure pump 81 sucks fuel in the low-pressure fuel pipe 52 a, pressurizes it, and sends it out to the high-pressure delivery pipe 83. Due to the operation of the high-pressure pump 81, fuel pressure pulsation due to the rotation of the cam occurs at the suction-side connection end of the high-pressure pump 81 of the low-pressure fuel pipe 52a. The vibration source of this pulsation is the fuel suction of the plunger 932 of the high-pressure pump 81.

  Here, the low-pressure fuel piping system has a specific resonance frequency determined by dimensions such as the total piping length L of the low-pressure fuel pipings 52 and 52a shown in FIG. 5 and the piping material (metal, resin, etc.). . Therefore, when the pulsation frequency of the fuel pressure matches the resonance frequency of the low pressure fuel piping system, a resonance phenomenon occurs in the low pressure fuel piping system.

  When a resonance phenomenon occurs in the low-pressure fuel piping system, the pulsation component superimposed on the fuel pressure increases. When a significant pulsation occurs in the fuel pressure, stress acts on the components constituting the low-pressure fuel piping system such as the low-pressure delivery pipe 53, which may be a factor of reducing the durability of the components.

  As shown in FIG. 4, the frequency of pulsation when a resonance phenomenon occurs in the low-pressure fuel piping system corresponds to a limited range of engine speed. This is because the frequency of pulsation changes with the rotational speed of the cam 933a, and the rotational speed of the cam 933a is proportional to the rotational speed of the engine 10. As a result, when the multiple of the rotational speed of the engine 10 matches the resonance frequency of the low-pressure fuel piping system, a noticeable pulsation appears in the fuel pressure.

  FIG. 6 is a diagram for explaining the relationship between the amplitude of the fuel pressure pulsation and the target fuel pressure. The horizontal axis of FIG. 6 shows the engine speed [rpm], and the vertical axis shows the pulsation amplitude [kPa] of the fuel pressure.

  As shown in FIG. 6, the amplitude of the fuel pressure pulsation increases in a specific rotational speed range. This specific rotational speed range is a rotational speed range centered on the engine rotational speed (corresponding to Ne1, Ne2, Ne3 in the figure) corresponding to the resonance frequency of the fuel piping system. In the following description, the engine rotation speed corresponding to the resonance frequency of the fuel piping system is referred to as “pulsation center”, and the engine rotation speed range in which the pulsation of fuel pressure becomes noticeable is referred to as “resonance range”.

  According to the experiments by the present inventors, when the target fuel pressure P0 is changed to 300 [kPa], 400 [kPa], 530 [kPa], and 644 [kPa], the fuel pressure pulsation is higher when the fuel pressure is higher in each resonance range. It turns out that the amplitude of becomes large. In particular, since the stack detection of the low-pressure fuel pressure sensor 53a is performed immediately after the engine is started, the target engine rotational speed is often set near the idle rotational speed NeX. However, if the target fuel pressure is increased near the idle rotational speed NeX, pulsation occurs. The amplitude of becomes larger.

  One of the causes that the amplitude of the fuel pressure pulsation increases as the target fuel pressure increases. In the high pressure pump 81 provided at the end of the low pressure fuel pipe 52a, the ability of the pulsation damper 92 to suppress the fuel pressure pulsation decreases as the fuel pressure increases. There are things to do.

  FIG. 7 is a view for explaining the relationship between the target fuel pressure and the internal volume change rate due to elastic deformation of the pulsation damper 92 and the amplitude of the fuel pressure pulsation. The horizontal axis of FIG. 7 shows the target fuel pressure [kPa], the left vertical axis shows the volume change rate [CC / Mpa], and the right vertical axis shows the pulsation amplitude [kPa] of the fuel pressure.

  Referring to FIG. 7, it can be seen that the amplitude of the fuel pressure pulsation increases as the volume change rate by the pulsation damper 92 decreases. In particular, when the target fuel pressure P0 is higher than 400 [kPa], the volume change rate decreases as the fuel pressure increases, so the amplitude of the fuel pressure pulsation increases.

  The fuel pressure range of 300 [kPa] to 530 [kPa] corresponds to the target fuel pressure range set during normal operation. On the other hand, 644 [kPa] corresponds to the target fuel pressure set at the time of restarting the engine at a high temperature, in addition to the diagnostic fuel pressure for detecting the stack of the fuel pressure sensor described above. This is to prevent the internal fuel from evaporating due to the high temperature of the engine.

(Control of engine speed)
FIG. 8 is a diagram for explaining the relationship between the fuel pressure pulsation and the engine speed. The horizontal axis of FIG. 8 shows the engine speed [rpm], and the vertical axis shows the case where the target fuel pressure P0 is changed to 300 [kPa], 400 [kPa], 530 [kPa], and 644 [kPa]. The detected value [kPa] of the fuel pressure sensor is shown.

  Regions RGN1, RGN2, and RGN3 in FIG. 8 indicate resonance ranges having pulsation centers at the engine rotational speeds Ne1, Ne2, and Ne3, respectively. As described above, when the engine rotational speed is within the resonance range, the fluctuation caused by the pulsation component appears significantly in the detection value of the fuel pressure sensor. Therefore, when the engine 10 is operated at a rotation speed within these resonance ranges, the deterioration of the components of the low-pressure fuel piping system with time progresses, thereby reducing the durability of the components.

  Therefore, in the present embodiment, when it is determined that the engine target rotational speed determined by the operating point for outputting the engine required power is within the resonance range, the engine target rotational speed is out of the resonance range. The operating point of the engine 10 is changed. By changing the engine speed outside the resonance range, resonance that occurs in the low-pressure fuel piping system can be suppressed. Thereby, since the pulsation of the fuel pressure is reduced, it is possible to prevent the durability of the component from being lowered.

  FIG. 9 is a diagram for explaining the control of the engine rotation speed in the present embodiment. In FIG. 9, the horizontal axis represents the engine rotation speed Ne, and the vertical axis represents the engine torque Te. The hybrid vehicle 1 shown in FIG. 1 can perform continuously variable transmission using the motor generators 20 and 30 and the power split mechanism 40. Therefore, the engine rotation speed can be set relatively freely with respect to the vehicle speed.

  Referring to FIG. 9, the fuel consumption line F is an operation line (hereinafter referred to as “the fuel efficiency line”) that combines operating points at which the engine 10 can be operated most efficiently (that is, with the optimum fuel consumption) using the engine rotational speed Ne and the engine torque Te as parameters. "Optimum fuel consumption line").

  On the other hand, the engine power PE is a product of the engine rotational speed Ne and the engine torque Te (PE = Ne × Te). Therefore, a line indicating the operating point of the engine 10 that outputs a constant PE (hereinafter referred to as “equal power”). The line is referred to as an inverse proportional curve as shown in FIG.

  The engine ECU 141 calculates the optimum fuel consumption rotational speed NeA and the optimum fuel consumption torque TeA from the intersection of the optimum fuel consumption line F and the line PE indicating the equal power line. By setting the operating point P0, which is a combination of the optimal fuel efficiency rotational speed NeA and the optimal fuel efficiency torque TeA, as a target operating point, and controlling the ignition timing and the fuel injection amount so as to realize this, the engine 10 is the most efficient engine. The required power PE can be output.

  Here, the case where the optimal fuel efficiency rotational speed NeA is included in the rotational speed range NL to NH that is the resonance range (RGN1 in the figure) will be considered. In this case, if the target fuel pressure is increased at the time of stack detection and high temperature restart, the pulsation of the fuel pressure in the low-pressure delivery pipe 53 increases due to the resonance phenomenon. As a result, the durability of the components of the low-pressure fuel piping system is reduced. End up.

  Accordingly, the engine ECU 141 changes the target value (target rotational speed) NeT of the engine rotational speed from the optimum fuel efficiency rotational speed NeA to the engine rotational speed NeB that deviates from the resonance range (rotational speed range NL to NH) to the high rotational side. (NeB> NeA). By avoiding the resonance phenomenon, the influence of the pulsation of the fuel pressure on the durability of the components of the low-pressure piping system can be reduced.

Hereinafter, the control for changing the engine speed will be described.
In order to change from the optimal fuel efficiency rotational speed NeA to the engine rotational speed NeB, as shown by an arrow A1 in FIG. 9, the engine operating point is changed from the operating point P0 to the operation on the high speed side on the optimal fuel efficiency line F. There is a method of shifting to the point P1. According to this method, the engine 10 can be operated with good energy efficiency while the engine power is increased.

  Alternatively, as shown by an arrow A2 in FIG. 9, there is a method of shifting the operating point P0 to the operating point P2 on the high rotation side on the equal power line PE. According to this method, although the engine power does not increase, the energy efficiency of the engine 10 is reduced.

  As shown in FIG. 9, the engine required power increases from PE to PE1 by shifting the target operating point from the operating point P0 to the operating point P1. A line PE1 indicated by a dotted line in FIG. 9 is an equal power line including the operating point P1. The engine power PE1 is a product of the engine speed NeB and the engine torque TeB1 (PE1 = NeB × TeB1).

  In the hybrid vehicle 1, the increase in engine required power (= PE1−PE) is an increase in the absolute value (| Pb |) of the charge / discharge power of the battery 70. That is, the battery 70 is charged by the increase in the engine required power. Specifically, in hybrid vehicle 1, the rotational speeds of sun gear SG, carrier CA and ring gear RG of power split mechanism 40, that is, the rotational speeds of motor generator 20, engine 10 and motor generator 30, are as shown in FIG. In addition, the relationship is connected by a straight line in the alignment chart.

  A vertical line Y1 in FIG. 10 indicates the rotation speed of the sun gear SG, that is, the rotation speed Nm1 of the motor generator 20 (MG1). The vertical line Y2 indicates the rotational speed of the carrier CA, that is, the rotational speed NE of the engine 10. Vertical line Y3 indicates the rotational speed of ring gear RG, that is, rotational speed Nm2 of motor generator 30 (MG2). The intervals between the vertical lines Y1 to Y3 are determined according to the gear ratio ρ of the power split mechanism 40.

  Referring to FIG. 10, collinear chart 200 (solid line) shows a state in which engine 10 is operating at operating point P0 in FIG. By shifting the operating point P0 of the engine 10 to the operating point P1 while keeping the rotational speed of the ring gear RG constant, the rotational speed Nm1 of the motor generator 20 becomes positive as shown in the collinear diagram 210 (dotted line). The direction changes (upward in the figure). The motor generator 20 outputs negative torque Tm1 (torque in a direction that suppresses the rotational speed of the engine 10) with respect to the output from the engine 10 to generate electric power.

  Engine direct transmission torque (−Tm1 / ρ) according to output torque Tm1 of motor generator 20 is transmitted to ring gear RG, and torque Tm2 is output from motor generator 30. The required torque set according to the accelerator opening and the vehicle speed is secured by the sum of the engine direct torque (-Tm1 / ρ) and the output torque Tm2 of the motor generator 30.

  At this time, the battery 70 calculates the power consumption (generated power) calculated based on the product of the output torque Tm1 and the rotational speed Nm1 of the motor generator 20 and the product of the output torque Tm2 and the rotational speed Nm2 of the motor generator 30. The sum of the generated power consumption (generated power) is input / output. That is, the charge / discharge power Pb of the battery 70 is the sum of the power (Tm1 × Nm1) input / output by the motor generator 20 and the power (Tm2 × Nm2) input / output by the motor generator 30 (Pb = Tm1). × Nm1 + Tm2 × Nm2). The charge / discharge power Pb is Pb> 0 when the battery 70 is discharged, and Pb <0 when the battery 70 is charged.

  Generally, the charging / discharging performance of the battery 70 is limited by setting the discharging power upper limit value Wout and the charging power upper limit value Win as constraint values for limiting charging / discharging of the battery 70. The discharge power upper limit value Wout indicates the upper limit value of the discharge power, and is set to Wout ≧ 0. When Wout = 0 is set, it means that discharging of the battery 70 is prohibited. Similarly, charging power upper limit value Win indicates the upper limit value of charging power, and is set to Win ≦ 0. When Win = 0 is set, it means that charging of the battery 70 is prohibited. Discharge power upper limit value Wout and charge power upper limit value Win are set according to the SOC and / or temperature of battery 70.

  As shown in FIG. 9, when the target operating point of the engine 10 is shifted from the operating point P0 to the operating point P1, the magnitude of the negative torque Tm1 output from the motor generator 20 increases. The power generated by the generator 20 increases. As a result, the charge / discharge power Pb of the battery 70 may exceed the charge power upper limit Win.

  Therefore, when the charge / discharge power Pb when the engine 10 is operated at the operating point P1 exceeds the charging power upper limit value Win of the battery 70, instead of shifting the target operating point to the operating point P1. , Shift to the operating point P2. Thereby, it is avoided that the battery 70 is overcharged. When shifting to the operating point P2, the engine torque decreases from TeA to TeB2, so the magnitude of the negative torque Tm1 output from the motor generator 20 also decreases, and as a result, the generated power of the motor generator 20 decreases. Further, in ring gear RG, the direct engine torque (−Tm / ρ) decreases, so that power consumption of motor generator 30 increases by increasing output torque Tm2 of motor generator 30 to ensure the required torque. As a result, the charge / discharge power Pb is suppressed from exceeding the charge power upper limit value Win of the battery 70.

  By the control as described above, the engine speed changing process according to the present embodiment is realized. In addition, since the engine speed changing process according to the present embodiment moves the operating point of the engine 10, the engine efficiency may be lowered. Therefore, in the present embodiment, in order to effectively suppress deterioration in durability of components of the low-pressure fuel piping system while maintaining good fuel economy, The engine speed changing process is executed.

  FIG. 11 to FIG. 13 are flowcharts for explaining the engine speed changing method according to the present embodiment. 11 to 13 can be realized by executing a program stored in advance in the control device 100.

  Referring to FIG. 11, engine ECU 141 detects the deterioration state of the components of the low-pressure fuel piping system in order to determine whether or not to execute the engine speed changing process. The deterioration state of the component is detected based on the detection value of the low-pressure fuel pressure sensor 53a. Specifically, engine ECU 141 compares the detected value of low-pressure fuel pressure sensor 53a with predetermined value Pmax in step S01. The predetermined value Pmax corresponds to a detection value of the low-pressure fuel pressure sensor 53a when the pulsation of the fuel pressure becomes significant. Based on the comparison result between the detected value and the predetermined value Pmax, engine ECU 141 determines whether or not a stress having a magnitude that affects the durability of the component is acting on the component. The predetermined value Pmax is, for example, a value (744 [kPa]) obtained by adding the pulsation amplitude (about 100 [kPa]) to the target fuel pressure P0 at the time of stack detection or high temperature restart to 644 [kPa]. Is set.

  When it is determined that the detected value of the fuel pressure sensor is equal to or greater than the predetermined value Pmax (when YES is determined in S01), the engine ECU 141 performs a time period (hereinafter, the detected value of the fuel pressure sensor is equal to or greater than the predetermined value Pmax in step S02). , Referred to as “fuel pressure pulsation large time”). The fuel pressure pulsation long time is calculated from a point in time when the deterioration of the component has not progressed (for example, when it is new or when the component is replaced). When it is determined that the detected value of the fuel pressure sensor is equal to or greater than the predetermined value Pmax, the value of the fuel pressure pulsation large time at that time is incremented.

  On the other hand, when the detected value of the low-pressure fuel pressure sensor 53a is smaller than the predetermined value Pmax (NO determination in S01), the process of step S02 is skipped.

  In FIG. 12, the engine speed changing process is executed according to the detection result of the deterioration state of the parts of the low-pressure fuel piping system. Specifically, in step S11, engine ECU 141 calculates engine target rotational speed NeA at which fuel efficiency is optimal from engine required power PE instructed by PM-ECU 140. The engine target rotational speed NeA is calculated based on the intersection of the optimum fuel consumption line F and the line PE indicating the equal power line in FIG.

  Next, in step S12, the engine ECU 141 determines whether or not the fuel pressure pulsation large time accumulated in step S02 of FIG. 11 is equal to or greater than a predetermined value Tth. The predetermined value Tth in step S02 is set according to the durability time of the parts of the low-pressure fuel piping system. The endurance time of a component corresponds to the time from the time when the deterioration of the component does not progress to the time when a failure occurs in the component. That is, the predetermined value Tth is a discriminating value for discriminating whether or not there is a possibility that a component will fail, and is set to a time shorter than the durability time of the component.

  When it is determined that the large fuel pressure pulsation time is equal to or greater than the predetermined value Tth (YES determination in S12), the engine ECU 141 determines that there is a high possibility that the component will fail due to a significant pulsation in the fuel pressure. . Therefore, the engine ECU 141 executes an engine speed changing process in order to suppress the occurrence of resonance in the low-pressure fuel piping system.

  Specifically, the engine ECU 141 first determines whether or not the target fuel pressure of the low pressure delivery pipe 53 is greater than or equal to a predetermined value. The predetermined value is a determination value for determining whether or not a significant pulsation occurs in the fuel pressure, and is set to a target fuel pressure (for example, 644 [kPa]) at the time of stack detection or high temperature restart, for example. .

  If it is determined in step S13 that the target fuel pressure is equal to or greater than the predetermined value (YES in S13), the engine ECU 141 determines in step S14 whether or not the engine target rotational speed NeA is within the resonance range. judge. The resonance range corresponds to the regions RGN1, RGN2, and RGN3 shown in FIG. 89. For example, the resonance range is within a rotational speed range of ± 150 [rpm] from the engine rotational speed (pulsation center) corresponding to the resonant frequency of the fuel piping system. is there.

  If it is determined in step S14 that the engine rotational speed NeA is within the resonance range (YES determination in S14), the engine ECU 141 proceeds to step S15, and the engine target rotational speed NeT is set so as to be out of the resonance range. To change. At this time, the engine ECU 141 changes the engine target rotation speed NeT from the engine target rotation speed NeA to the engine target rotation speed NeB that deviates from the resonance range to the high rotation side. For example, when the resonance range is the pulsation center ± 150 [rpm], the engine target rotation speed NeA is shifted to the high rotation side by 300 [rpm] corresponding to the width of the resonance range, thereby obtaining the engine target rotation speed. NeT deviates from the resonance range.

  On the other hand, when the fuel pressure pulsation large time is shorter than the predetermined value Tth (NO in S12), the target fuel pressure is lower than the predetermined value (NO in S13), or the engine target rotational speed NeA is not within the resonance range. If it is determined (NO determination in S14), the engine ECU 141 proceeds to step S16, and adopts the engine target rotation speed NeA as it is as the engine target rotation speed NeT.

  When the engine target rotational speed NeT is determined in step S15 or S16, the control is returned to the main routine. Thereafter, the engine 10 is controlled to achieve the engine target rotational speed NeT.

  With reference to FIG. 13, details of the process in step S15 of FIG. 12 (engine speed changing process) will be described.

  When the engine target rotational speed NeB outside the resonance range is determined as the engine target rotational speed NeT, the engine ECU 141 operates in step S21 to correspond to the engine target rotational speed NeB on the optimum fuel consumption line F shown in FIG. (Corresponding to the operating point P1 in FIG. 9) is set.

  Further, in step S22, engine ECU 141 sets an operating point (corresponding to operating point P2 in FIG. 9) corresponding to engine target rotational speed NeB on equal power line PE shown in FIG.

  Next, in step S23, engine ECU 141 assumes a case where engine 10 is operated at operating point P1 (engine rotational speed NeB and engine torque TeB1), and calculates charging / discharging power Pb of battery 70 in this case. The charge / discharge power Pb is the sum of the power (Tm1 × Nm1) input / output by the motor generator 20 and the power (Tm2 × Nm2) input / output by the motor generator 30 (Pb = Tm1 × Nm1 + Tm2 × Nm2). .

  In PM-ECU 140, in step S24, charging power upper limit value Win and discharging power upper limit value Wout of battery 70 are set in accordance with the SOC of battery 70 calculated by battery ECU 143 and / or the temperature of battery 70.

  In step S25, the engine ECU 141 determines whether or not the charge / discharge power Pb when the engine 10 is operated at the operating point P1 is within the range of the charge / discharge limit (Win to Wout) of the battery 70.

  When it is determined that the charge / discharge power Pb is within the range of Win to Wout of the battery 70 (when YES is determined in S25), the engine ECU 141 proceeds to step S26 and sets the target operating point of the engine 10 as the operating point P1. Set to. Then, the operating state of the engine 10 is controlled so that the engine 10 operates at the operating point P1 (engine rotational speed NeB and engine torque TeB1).

  On the other hand, when it is determined that the charge / discharge power Pb exceeds the range of Win to Wout of the battery 70 (NO determination in S25), the engine ECU 141 proceeds to step S27 and sets the target operating point as the operating point. Set to P2. Then, the operating state of the engine 10 is controlled so that the engine 10 operates at the operating point P2 (engine rotational speed NeB and engine torque TeB2).

  As described above, according to the present embodiment, when it is determined that the engine target rotational speed determined by the target operating point of engine 10 is within the resonance range, the engine target rotational speed is out of the resonance range. Thus, the target operating point is changed. As a result, the engine speed is changed outside the resonance range, so that resonance occurring in the low-pressure fuel piping system can be suppressed. As a result, the pulsation of the fuel pressure in the low-pressure fuel piping system is reduced, so that it is possible to prevent the durability of the parts from being lowered.

  In addition, when it is determined that the deterioration of the parts of the low-pressure fuel piping system with time has progressed, it is possible to reduce the durability of the parts while maintaining good fuel efficiency by executing the engine speed changing process. Can be suppressed.

[Modification]
In the above-described embodiment, as the engine speed changing process, the engine target speed is changed from the optimum fuel consumption speed to the engine speed deviating from the resonance range to the high speed side. It is good also as a structure which changes to the engine speed which deviated from the low rotation side from.

  FIG. 14 is a diagram for describing control of engine rotation speed in a modification of the present embodiment. The horizontal axis of FIG. 14 shows the engine rotational speed Ne, and the vertical axis shows the engine torque Te.

  Referring to FIG. 14, when the optimum fuel efficiency rotational speed NeA is included in the rotational speed range NL to NH that is the resonance range (RGN2 in the figure), the engine ECU 141 determines that the engine target rotational speed NeT Is changed from the optimum fuel efficiency rotation speed NeA to the engine rotation speed NeB3 deviating from the resonance range to the low rotation side (NeB3 <NeA).

  Specifically, as indicated by an arrow A3 in FIG. 14, the target operating point is shifted from the operating point P0 to the operating point P3 on the low speed side on the optimum fuel consumption line F. By shifting the target operating point from the operating point P0 to the operating point P3, the engine required power decreases from PE to PE3. A line PE3 indicated by a dotted line in FIG. 14 is an equal power line including the operating point P3. The engine power PE3 is a product of the engine rotation speed NeB and the engine torque TeB1 (PE1 = NeB3 × TeB3).

  In the present modification, this reduction in engine required power (= PE3-PE) is taken as a reduction in charge / discharge power | Pb | PM-ECU 140 sets charge / discharge required power Pb * for SOC control of battery 70. The charge / discharge required power Pb * is set to Pb *> 0 when prompting to discharge the battery 70, and set to Pb * <0 when prompting the battery 70 to be charged. The engine required power PE is indicated by the sum of the power (travel power) Pr * required for traveling of the hybrid vehicle 1 and the charge / discharge required power Pb * (PE = Pr * −Pb *).

  In the SOC control, the charge / discharge required power Pb * is set so that the SOC of the battery 70 approaches the SOC target value. That is, when the SOC is lower than the SOC target value, the engine required power PE becomes larger than the traveling power Pr by setting Pb * <0. On the contrary, if the SOC is higher than the SOC target value, the engine required power PE becomes smaller than the traveling power Pr by setting Pb *> 0.

  As described above, when the target operating point is shifted from the operating point P0 to the operating point P3, charging / discharging with respect to the same SOC deviation (insufficient SOC with respect to the SOC target value) compared to normal SOC control. Charge / discharge required power Pb * (Pb * <0) is set so that the absolute value (| Pb * |) of required power Pb * is reduced. According to this modification, compared with the case where the target operating point is shifted to the high rotation side on the equal power line (in the case of the arrow A2 in FIG. 9), the charge amount of the battery 70 is reduced by | Pb * | Although it decreases, a decrease in the energy efficiency of the engine 10 can be suppressed.

  Referring to FIG. 8 again, when the engine target rotational speed is in the resonance range shown in region RGN2 or RGN3, the target operating point is set to the operating point on the high speed side on the optimal fuel consumption line F from the optimal fuel consumption operating point P0. A method of shifting to P1 (FIG. 9), a method of shifting to the operating point P2 on the high revolution side on the equal power line PE (FIG. 9), and an operating point P3 on the low revolution side on the optimum fuel consumption line F (FIG. 14). ) To shift. The SOC control of the battery 70 and the engine are selected by selecting any one of these three methods according to the charge / discharge limit (the charge power upper limit value Win and the discharge power upper limit value Wout) of the battery 70 and the energy efficiency of the engine 10. It is possible to reduce the pulsation of the fuel pressure in the low pressure fuel piping system without affecting the energy efficiency of 10.

  The hybrid vehicle 1 shown in FIG. 1 is a series / parallel type hybrid vehicle, and is configured to be able to travel using at least one of the engine 10 and the motor generator 30 as a drive source. The present invention can be applied to any hybrid vehicle. In other words, the present invention can be commonly applied to hybrid vehicles having a configuration in which the SOC of the power storage device can be increased by the output of the engine.

  Moreover, although the engine which has a cylinder injection valve and a port injection valve was illustrated in FIG. 2, this invention can also be applied to the engine which does not have a cylinder injection valve but has only a port injection valve.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  DESCRIPTION OF SYMBOLS 1 Hybrid vehicle, 10 Engine, 11 Cylinder, 15 Fuel supply apparatus, 16 Rotating shaft, 20, 30 Motor generator, 21 Intake port, 36 Intake manifold, 40 Power split mechanism, 50 Low pressure fuel supply mechanism, 51 Fuel pumping part, 52 , 52a Low pressure fuel pipe, 53 Low pressure delivery pipe, 53a Low pressure fuel pressure sensor, 54 port injection valve, 54a, 84a Injection hole, 58 Reduction mechanism, 62 Drive wheel, 70 Battery, 80 High pressure fuel supply mechanism, 81 High pressure pump, 82 High pressure fuel piping, 82a Check valve, 83a High pressure delivery pipe, 84 In-cylinder injection valve, 90 Upstream side pipe, 91 Downstream side pipe, 92 Pulsation damper, 93 High pressure pump body, 94 Electromagnetic spill valve, 100 Control device, 140 PM -ECU, 141 engine ECU, 142 Motor ECU, 143 Battery ECU, 511 Fuel tank, 512 Feed pump, 513 Suction filter, 514 Fuel filter, 515 Relief valve, 516 Fuel piping, 931 Pump housing, 931a Pressure chamber, 932 Plunger, 933 Camshaft, 933a cam, 934 follower lifter, 935 spring.

Claims (1)

Engine,
A power storage device;
An electric motor that generates a vehicle driving force by electric power from the power storage device;
A fuel supply device for supplying fuel to the engine;
A control device for controlling the engine, the electric motor and the fuel supply device;
The fuel supply device includes:
A reservoir for storing fuel for injection into the intake passage;
A feed pump that pressurizes and supplies fuel to the reservoir;
A high-pressure reservoir that stores fuel for injection into the cylinder;
A high-pressure pump that is driven in accordance with the rotation of the engine, pressurizes the fuel, and supplies the fuel to the high-pressure reservoir.
The pressure of the fuel stored in the storage part is set lower than the pressure of the fuel stored in the high-pressure storage part,
The control device controls the output power of the engine according to the sum of the traveling power required for vehicle travel and the charge / discharge power of the power storage device for controlling the SOC of the power storage device, and stores in the storage section. Configured to control the feed pump so that the pressure of the fuel to be achieved becomes a target fuel pressure,
The controller is
When it is determined that the target rotational speed of the engine determined by the operating point for outputting the power required for the engine is within a resonance range in which a resonance phenomenon can occur in the reservoir, the target rotational speed Operation of the engine along an optimal operating line that is preset according to the efficiency of the engine so that the speed is out of the resonance range, or along an equal power line that is a set of operating points at which the engine output power is the same. A hybrid vehicle that changes points.

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