An engine including a main fuel injection valve, a pilot fuel injection valve, a liquid fuel supply rail pipe, and a pilot fuel supply rail pipe. The main fuel injection valve supplies liquid fuel from the liquid fuel supply rail pipe to a combustion chamber during combustion in a diffusion combustion system. The pilot fuel injection valve supplies pilot fuel from the pilot fuel supply rail pipe to the combustion chamber in order to ignite gaseous fuel during combustion in a premixed combustion system. The liquid fuel supply rail pipe is disposed at one side of an imaginary vertical plane including an axis of a crank shaft. The pilot fuel supply rail pipe is disposed at the side of the imaginary vertical plane at which the liquid fuel supply rail pipe is disposed.

A vehicle includes a residual pressure holding valve provided downstream a feed pump of a fuel to hold a pressure in a fuel pipe leading to the port injection valve. Residual pressure holding valve is opened to return the fuel in the fuel pipe to the fuel tank when the pressure in the fuel pipe exceeds a valve opening pressure, and closed when the pressure in the fuel pipe is lower than the valve opening pressure. At the time of a request to reduce a target pressure of the fuel to be supplied to the electric feed pump, a control device refrains from causing the target pressure to decrease when a load of the engine is smaller than a prescribed value, and causes the target pressure to decrease when the load of the engine is greater than the prescribed value.

Methods and systems are provided for detecting a temperature of an engine fuel rail at a plurality of locations along the engine fuel rail. In one example, a method may include detecting temperatures along the engine fuel rail with a plurality of metal film thermocouples adhered to the engine fuel rail and arranged proximate to engine fuel injectors, and adjusting fuel injector operation and/or fuel rail pressure in response to the detected fuel rail temperatures.

A high-pressure pump includes: a low-pressure chamber, into which low-pressure fuel discharged from a low-pressure pump flows; a pressurizing chamber, which pressurizes the low-low-pressure fuel; and a leak chamber, into which leaked fuel from the pressurizing chamber flows. The leaked fuel of the leak chamber is suctioned into and is pressurized in the pressurizing chamber together with the low-pressure fuel of the low-pressure chamber, so that the leaked fuel is discharged to an outside of the high-pressure pump as high-pressure fuel. Furthermore, a suction check valve, which is placed between the low-pressure chamber and the leak chamber, limits backflow of the leaked fuel of the leak chamber to the low-pressure chamber when the high-pressure pump does not supply the high-pressure fuel.

Fueling systems and methods are disclosed. Various fueling systems may comprise a single fuel pump configured to supply fuel to a first fuel rail at a first fuel pressure along a first fuel circuit and configured to supply fuel to a second fuel rail at a second fuel pressure along a second fuel circuit, wherein the first fuel rail and second fuel rail are arranged in parallel, and the first fuel circuit is independent of the second fuel circuit.

A fuel supply device includes an injector, a fuel pressurization device and an ECU. The fuel pressurization device includes an electromagnetic valve. The fuel pressurization device is configured to pressurize a fuel in accordance with opening/closing of the electromagnetic valve and discharge the fuel toward the injector. The ECU is configured: to control the opening/closing of the electromagnetic valve to adjust the fuel amount discharged toward the injector; to execute an operation sound suppression control during a low-load operation of an engine by reducing an opening/closing frequency of the electromagnetic valve and increasing the fuel amount discharged for each opening/closing of the electromagnetic valve; not to execute the operation sound suppression control when a partial lift injection is in progress; and to execute the operation sound suppression control when the partial lift injection is not in progress.

Methods and systems are provided for reducing hot fuel vapor formation in a port injection fuel rail. In one example, a method may include operating a dual fuel injection system with at least a calibrated minimum amount of port fuel injection over a wide range of engine operating conditions, even as conditions change. A direct fuel injection amount is adjusted in accordance.

Methods and systems are provided for delivering fuel to a port injector fuel rail in a port fuel direct injection (PFDI) engine. In one example, the port injector fuel rail may receive fuel from each of a compression chamber and a step chamber of a direct injection fuel pump coupled in the PFDI engine. In this way, pressurized fuel may be supplied to the port injector fuel rail during an entire cycle of the direct injection fuel pump.

An engine including a main fuel injection valve, a pilot fuel injection valve, a liquid fuel supply rail pipe, and a pilot fuel supply rail pipe. The main fuel injection valve supplies liquid fuel from the liquid fuel supply rail pipe to a combustion chamber during combustion in a diffusion combustion system. The pilot fuel injection valve supplies pilot fuel from the pilot fuel supply rail pipe to the combustion chamber in order to ignite gaseous fuel during combustion in a premixed combustion system. The liquid fuel supply rail pipe is disposed at one side of an imaginary vertical plane (P1) including an axis of a crank shaft. The pilot fuel supply rail pipe is disposed at the side of the imaginary vertical plane at which the liquid fuel supply rail pipe is disposed.

A fuel injection system for an engine, the fuel injection system includes injectors and an electronic control unit. The injectors include needle valves; and the ECU is configured to: (i) execute partial lift injection and full lift injection with the injectors, the partial lift injection being injection during which the needle valve does not reach a fully-open state and the full lift injection being injection during which the needle valve reaches the fully-open state; (ii) operate the engine in a partial lift injection region where the injection of a required injection amount of a fuel is shared by the partial lift injection and the full lift injection; and (iii) perform the amount of correction of the required injection amount with respect to the injection amount shared by the full lift injection when the required injection amount is corrected while the engine is operated in the partial lift injection region.