Methods and systems are provided for reducing fueling errors resulting from pressure pulsations in a port injection fuel rail. The pressure pulsations result from pressure pulsations generated in a high pressure fuel pump delivering fuel to both the port injection fuel rail and a direct injection fuel rail. A center of a port injection fuel pulse is repositioned on a nearest fuel rail pressure sampling point in the advanced direction to improve the accuracy of the delivered fuel pulse.

The invention relates to a high-pressure fuel pump for supplying fuel to a first injection device of an internal combustion engine, in particular of a motor vehicle, having at least one first low-pressure port, via which the fuel can be fed to the high-pressure fuel pump from a low-pressure fuel pump for conveying the fuel, having at least one low-pressure chamber, to which at least a part of the fuel fed to the high-pressure fuel pump via the first low-pressure port can be fed, having at least one second low-pressure port, for conducting the fuel conveyed by means of the low-pressure fuel pump and fed to the high-pressure fuel pump away from the high-pressure fuel pump to a second injection device provided in addition to the first injection device.

For an optimized metering of fuel and water for the operation of an internal combustion engine in which a direct injection and an intake manifold injection are provided for metering fuel into the internal combustion engine, and in which the internal combustion engine is assigned a system for water injection, a same intake manifold injector is used for both water and fuel injection.

A pump device for an internal combustion engine, having a high-pressure fuel pump for supplying fuel to a first injection device, having at least one low-pressure inlet, via which the fuel is fed to the high-pressure fuel pump from a low-pressure fuel pump, having at least one low-pressure outlet for conducting the fuel conveyed by the low-pressure fuel pump and fed via the low-pressure inlet to the high-pressure fuel pump out of the high-pressure fuel pump, and having at least one low-pressure port, for conducting fuel conveyed by the low-pressure fuel pump to a second injection device. At least one mixing region mixes the fuel flowing through the low-pressure outlet with fuel fed to the mixing region from the low-pressure fuel pump upstream of the high-pressure fuel pump. The low-pressure port is fluidically connected to the mixing region, and the low-pressure inlet is supplied with fuel from the mixing region.

A multi-fuel rail apparatus for an internal combustion engine communicates fuel from 10 a first fuel source and a second fuel source to a plurality of fuel injectors. Each fuel injector receives fuel from the multi-fuel rail apparatus through a branch connection for each fuel. The multi fuel rail apparatus has a first elongate member including a first longitudinal bore spaced apart from a second longitudinal bore and first and second fuel inlets for fluidly communicating first and second fuels into the first and 15 second longitudinal bores respectively. There is a branch connecting structure for each fuel injector along the first elongate member for fluidly connecting the first and second longitudinal bores with respective branch connections from respective fuel injectors.

A fuel injection control device includes processing circuitry, which executes an estimating process to estimate pressure in first and second fuel storage members connected to first and second fuel injection valves. The estimating process includes: estimating the pressure in the first fuel storage member based on a detection value of a pressure sensor that detects the pressure in the first fuel storage member and a cycle of pulsation in the first fuel storage member, which is determined in accordance with an interval of fuel injections in a first bank; and estimating the pressure in the second fuel storage member by assuming that a phase of a periodic fluctuation of the pressure in the second fuel storage member and a phase of a periodic fluctuation of the pressure in the first fuel storage member are in antiphase.

A fuel system includes a low-pressure fuel delivery unit; a high-pressure fuel delivery unit which has a drive region and a delivery region such that the drive region supplies fuel to the delivery region and such that the delivery region supplies fuel to a high-pressure fuel injector; a low-pressure fuel supply passage which supplies fuel from the low-pressure fuel delivery unit to the drive region of the high-pressure fuel delivery unit; a cooling passage which receives fuel from the drive region of the high-pressure fuel delivery unit; and a low-pressure fuel injector supply passage which is in direct fluid communication with the low-pressure fuel supply passage and which supplies fuel to a low-pressure fuel injector from the cooling passage.

An engine device, which employs various types of fuels, plural fuel pipes can compactly be disposed without being thermally affected by exhaust gas. In the engine device, a gas fuel pipe that supplies gas fuel to a gas injector, a fuel oil pipe that supplies liquid fuel to a main fuel injection valve are disposed to be divided on both sides of a row of head covers arranged in a line. In addition, in the engine device, an intake manifold that supplies air taken in by a main combustion chamber toward an intake valve extends in parallel to the row of head covers in a cylinder block, and the fuel gas pipe and the intake manifold are arranged on the same side of the row of head covers.

A dual fuel common rail engine supplies pressurized natural gas and liquid diesel fuel at different pressures through a co-axial quill assembly for direct injection from a single fuel injector into an engine cylinder. Pressure waves in the gaseous fuel common rail are damped in a pressure damping chamber of the co-axial quill assembly to promote consistent gaseous fuel injection rates and quantities from the fuel injector.

Methods and systems are provided for operating a lift pump of an engine fuel system. In one example, a method may comprise closed loop operating a lift pump of a fuel system based on a difference between a desired fuel rail pressure and an estimated fuel rail pressure, and open loop operating the lift pump to the desired fuel rail pressure in response to a fuel flow rate in a direction of a fuel rail through a check valve positioned between the lift pump and the fuel rail decreasing to a threshold. Thus, outputs from a fuel rail pressure sensor may not be used to adjust lift pump operation when an amount of fuel flowing to the fuel rail decreases to a threshold.