Abstract: A discharge valve (30) is provided in a high-pressure fuel passage (31) to allow fuel to pass through the discharge valve (30) only in a direction from a high-pressure fuel pump (20) toward a delivery pipe (50). A communication passage (41) with an orifice (42) is formed integrally with the discharge valve (30) in parallel with the discharge valve (30) to connect areas upstream and downstream of the discharge valve (30). When a fuel pressure in the delivery pipe (50) is increased to a target pressure using the high-pressure fuel pump (20), an amount of the fuel, which does not interfere with an increase in the fuel pressure, flows through the orifice (42). A check valve (40) is provided in the communication passage (41), and opened to allow the fuel to pass through the check valve (40) only in the direction from the delivery pipe (50) toward the high-pressure fuel pump (20), when the fuel pressure is higher than a first predetermined pressure.

Abstract: In one embodiment, a small-diameter opening (42b) is formed in the central portion of a valve element (42) included in a check valve (40) of a high pressure fuel pump (1). A needle valve (44) is provided integrally with a valve element (35a) of an electromagnetic spill valve (30), and the opening (42b) of the valve element (42) can be opened and closed with a tip portion of the needle valve (44). When the high pressure fuel pump (1) switches from the drive state to the stopped state, the needle valve (44) retreats from the opening (42b) of the valve element (42) in conjunction with the movement of the valve element (35a) of the electromagnetic spill valve 30, thus forming a micro gap.

Abstract: In one embodiment, a small-diameter opening (42b) is formed in the central portion of a valve element (42) included in a check valve (40) of a high pressure fuel pump (1). A needle valve (44) is provided integrally with a valve element (35a) of an electromagnetic spill valve (30), and the opening (42b) of the valve element (42) can be opened and closed with a tip portion of the needle valve (44). When the high pressure fuel pump (1) switches from the drive state to the stopped state, the needle valve (44) retreats from the opening (42b) of the valve element (42) in conjunction with the movement of the valve element (35a) of the electromagnetic spill valve 30, thus forming a micro gap.

Abstract: A discharge valve (30) is provided in a high-pressure fuel passage (31) to allow fuel to pass through the discharge valve (30) only in a direction from a high-pressure fuel pump (20) toward a delivery pipe (50). A communication passage (41) with an orifice (42) is formed integrally with the discharge valve (30) in parallel with the discharge valve (30) to connect areas upstream and downstream of the discharge valve (30). When a fuel pressure in the delivery pipe (50) is increased to a target pressure using the high-pressure fuel pump (20), an amount of the fuel, which does not interfere with an increase in the fuel pressure, flows through the orifice (42). A check valve (40) is provided in the communication passage (41), and opened to allow the fuel to pass through the check valve (40) only in the direction from the delivery pipe (50) toward the high-pressure fuel pump (20), when the fuel pressure is higher than a first predetermined pressure.

Abstract: Fuel pipes guide fuel from a fuel tank provided in a rear area of the vehicle to a low-pressure fuel supply system and a high-pressure fuel supply system, respectively, for injecting the fuel to an engine provided in a front area of the vehicle. A branch point between the fuel pipes is arranged in the vicinity of the fuel tank to secure a long pipe length between the low-pressure fuel supply system and the high-pressure fuel supply system. This can suppress variation in fuel pressure at the low-pressure fuel supply system attributable to the fuel that is discharged from the high-pressure fuel pump within the high-pressure fuel supply system back to the fuel pipe.

Abstract: A pulsation damper is provided between and in series with a low pressure fuel system pipe and a high pressure pump of a fuel supply system. During startup of an engine, low pressure fuel supplied via the low pressure fuel system pipe is injected from an intake passage fuel injector. When the fuel pressure is equal to or less than a fuel pressure at which good startability can be maintained, the pulsation damper closes off communication between the high pressure fuel system pipe and the low pressure fuel system pipe using the spring force of a spring.

Abstract: An engine ECU stores a map in which a region at high temperature and high pressure, a region at low temperature and low pressure, and a region provided therebetween are defined by the relationship between the temperature and pressure of fuel and the saturation fuel vapor pressure of the fuel. The engine ECU executes a program including the following steps: when start-up of the engine is requested, detecting the engine cooling water temperature and the fuel pressure; if the detection results fall into the region, setting a pre-feed time; pre-feeding until the fuel pressure reaches a desired fuel pressure threshold; and when the fuel pressure reaches the fuel pressure threshold, starting cranking. In this way, start-up failure due to fuel vapor can be avoided without unnecessarily actuating a fuel pump.

Abstract: A pulsation damper is provided between and in series with a low pressure fuel system pipe and a high pressure pump of a fuel supply system. During startup of an engine, low pressure fuel supplied via the low pressure fuel system pipe is injected from an intake passage fuel injector. When the fuel pressure is equal to or less than a fuel pressure at which good startability can be maintained, the pulsation damper closes off communication between the high pressure fuel system pipe and the low pressure fuel system pipe using the spring force of a spring.

Abstract: An engine ECU stores a map in which a region at high temperature and high pressure, a region at low temperature and low pressure, and a region provided therebetween are defined by the relationship between the temperature and pressure of fuel and the saturation fuel vapor pressure of the fuel. The engine ECU executes a program including the following steps: when start-up of the engine is requested, detecting the engine cooling water temperature and the fuel pressure; if the detection results fall into the region, setting a pre-feed time; pre-feeding until the fuel pressure reaches a desired fuel pressure threshold; and when the fuel pressure reaches the fuel pressure threshold, starting cranking. In this way, start-up failure due to fuel vapor can be avoided without unnecessarily actuating a fuel pump.

Abstract: An electrically driven type low-pressure fuel pump whose flow rate can be set draws fuel from a fuel tank and discharges it at a prescribed pressure commonly to a low-pressure fuel supply system including intake manifold injectors and a low-pressure delivery pipe and to a high-pressure fuel supply system including in-cylinder injectors, a high-pressure delivery pipe and a high-pressure fuel pump. The discharge flow rate of the low-pressure fuel pump is set based on required supply quantities to the low-pressure fuel supply system and to the high-pressure fuel supply system obtained according to the engine operation conditions. The discharge quantity of the fuel pump in the internal combustion engine can be set as appropriate, and thus, deterioration in fuel efficiency due to excessive flow rate setting and operation failure due to insufficient fuel supply can be prevented, whereby reliability is improved.

Abstract: The engine ECU executes a program including the step of detecting an engine coolant temperature, the step of detecting an engine speed and an engine load, the step of estimating a temperature at a tip end of an in-cylinder injector based on the engine coolant temperature, the engine speed and the engine load, and, when the temperature at the tip end is greater than a guaranteed temperature, the step of calculating a drive duty of a high-pressure fuel pump that ensures a decrease of the temperature at the tip end of the in-cylinder injector to the guaranteed temperature, and the step of controlling the high-pressure fuel pump using the drive duty.

Abstract: The engine ECU executes a program including the step of detecting an engine coolant temperature, the step of detecting an engine speed and an engine load, the step of estimating a temperature at a tip end of an in-cylinder injector based on the engine coolant temperature, the engine speed and the engine load, and, when the temperature at the tip end is greater than a guaranteed temperature, the step of calculating a drive duty of a high-pressure fuel pump that ensures a decrease of the temperature at the tip end of the in-cylinder injector to the guaranteed temperature, and the step of controlling the high-pressure fuel pump using the drive duty.

Abstract: A fuel supply system according to the present invention includes a first delivery pipe for intake passage injection and a second delivery pipe for cylinder injection. The second delivery pipe is provided with a relief valve. A fuel discharge section of the relief valve is connected to the first delivery pipe via a relief passage.

Abstract: The engine ECU executes a program including the step of detecting an engine coolant temperature, the step of detecting an engine speed and an engine load, the step of estimating a temperature at a tip end of an in-cylinder injector based on the engine coolant temperature, the engine speed and the engine load, and, when the temperature at the tip end is greater than a guaranteed temperature, the step of calculating a drive duty of a high-pressure fuel pump that ensures a decrease of the temperature at the tip end of the in-cylinder injector to the guaranteed temperature, and the step of controlling the high-pressure fuel pump using the drive duty.

Abstract: The engine ECU executes a program including the step of detecting an engine coolant temperature, the step of detecting an engine speed and an engine load, the step of estimating a temperature at a tip end of an in-cylinder injector based on the engine coolant temperature, the engine speed and the engine load, and, when the temperature at the tip end is greater than a guaranteed temperature, the step of calculating a drive duty of a high-pressure fuel pump that ensures a decrease of the temperature at the tip end of the in-cylinder injector to the guaranteed temperature, and the step of controlling the high-pressure fuel pump using the drive duty.

Abstract: A double system of fuel injection type internal combustion engine includes: a direct injection injector and a port fuel injection injector; a control unit for changing a fuel injection distribution ratio of fuels injected from these injectors; a delivery pipe for the direct injection injector; a high pressure fuel pump; a fuel pressure sensor and a fuel temperature sensor for detecting a fuel pressure and a fuel temperature in the delivery pipe; and a fuel regulating unit for regulating the fuel pressure and fuel temperature in the delivery pipe. The control unit can control the fuel regulating unit so as to lower the exceeding value thereof when the fuel injection distribution ratio of the port fuel injection injector is higher than that of the direct injection injector and at least one of the fuel pressure value and fuel temperature value exceeds an aimed value.

Abstract: The engine ECU executes a program including the step of detecting an engine coolant temperature, the step of detecting an engine speed and an engine load, the step of estimating a temperature at a tip end of an in-cylinder injector based on the engine coolant temperature, the engine speed and the engine load, and, when the temperature at the tip end is greater than a guaranteed temperature, the step of calculating a drive duty of a high-pressure fuel pump that ensures a decrease of the temperature at the tip end of the in-cylinder injector to the guaranteed temperature, and the step of controlling the high-pressure fuel pump using the drive duty.

Abstract: A double system of fuel injection type internal combustion engine includes: a direct injection injector and a port fuel injection injector; a control unit for changing an fuel injection distribution ratio of fuels injected from these injectors; a delivery pipe connected to the direct injection injector so as to supply the fuel to the direct injection injector; a high pressure fuel pump for supplying the fuel under pressure to the direct injection injector through the delivery pipe; a fuel pressure sensor and a fuel temperature sensor for detecting a fuel pressure and a fuel temperature in the delivery pipe; and a fuel regulating unit for regulating the fuel pressure and fuel temperature in the delivery pipe.

Abstract: Fuel pipes guide fuel from a fuel tank provided in a rear area of the vehicle to a low-pressure fuel supply system and a high-pressure fuel supply system, respectively, for injecting the fuel to an engine provided in a front area of the vehicle. A branch point between the fuel pipes is arranged in the vicinity of the fuel tank to secure a long pipe length between the low-pressure fuel supply system and the high-pressure fuel supply system. This can suppress variation in fuel pressure at the low-pressure fuel supply system attributable to the fuel that is discharged from the high-pressure fuel pump within the high-pressure fuel supply system back to the fuel pipe.

Abstract: An ECU for an internal combustion engine predicts change in the driving state of the engine when switching from port injection mode to in-cylinder injection mode. In accordance with the prediction, the ECU actuates a high-pressure pump before entering the in-cylinder injection mode to pressurize the fuel supplied to an air-intake passage injector.