Systems and methods for sensing fuel vapor pressure are provided. In one example, a method for a vehicle comprises: during an engine start after the engine has been off for at least a minimum duration, actively controlling fuel pressure in the fuel system to a vapor-liquid volume ratio greater than zero and then recording sensed fuel pressure and temperature in the fuel system. In this way, the vapor pressure of a fuel at a given temperature may be accurately measured during isothermal conditions, thereby improving an estimation of fuel volatility.

Systems and methods for improving fuel injection of an engine that includes a cylinder receiving fuel from two different fuel injectors is disclosed. In one example, fuel is supplied to port fuel injectors and direct fuel injectors via a same high pressure fuel pump, and high pressure port fuel injection is activated at times where direct fuel injection would supply less fuel than is desired or an inconsistent amount of fuel.

A method for starting an internal combustion engine with a fuel tank and a low-pressure pump which pumps gasoline out of the fuel tank at a low-pressure to a high-pressure pump that pumps the gasoline at a high-pressure to injectors of the internal combustion engine. An electronic controller is provided for controlling and/or regulating the low-pressure pump, the high-pressure pump, and the injectors. After a start pulse for the internal combustion engine, the method: checks whether a formation of vapor bubbles in the gasoline is possible on the low-pressure side during a hot start. If not possible, then the normal low-pressure is set. If possible, then a low pressure which is high enough that the formation of vapor bubbles is not possible on the low-pressure side is set, and the normal low-pressure is set after a period of time. The problem of vapor bubble formation is prevented in an inexpensive or cost neutral manner via the method.

Methods and systems are provided for controlling a low pressure pump in port fuel direct injection (PFDI) engines. One method includes, when operating a high pressure pump in a default pressure mode, pulsing the low pressure pump when pressure in a high pressure fuel rail decreases below a threshold. The method further includes, when operating the high pressure pump in a variable pressure mode, pulsing the low pressure pump based on presence of fuel vapor at an inlet of the high pressure pump.

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.

A method for controlling a high-pressure pump for the injection of fuel into a combustion engine, the high-pressure pump being connected to a camshaft of the combustion engine, wherein the high-pressure pump is controlled in a camshaft-synchronous manner by ascertaining an angular offset between the flank positions of a camshaft pulse-generating wheel and a predefinable point above the bottom dead center of a cam of the high-pressure pump on the camshaft.

A fuel injection valve includes: a movable arrangement that is coupled to a movable core and a needle while a movable flow passage, which forms a part of a flow passage of the fuel injection valve, is formed at an inside of the movable arrangement; and a valve main body that receives the movable arrangement. The movable arrangement has: a first flow-restricting portion that reduces a cross-sectional area of a portion of the movable flow passage; and a second flow-restricting portion that is spaced away from the first flow-restricting portion and reduces a cross-sectional area of another portion of the movable flow passage to a cross-sectional area that is equal to or larger than a cross-sectional area of the first flow-restricting portion. A distance between the first flow-restricting portion and the second flow-restricting portion is larger than an equivalent diameter of the cross-sectional area of the second flow-restricting portion.

A method for operating an internal combustion engine having an injection system which has a high-pressure accumulator, high pressure in the high-pressure accumulator being controlled via a suction throttle on the low-pressure side, acting as a first pressure control element in a first high-pressure control loop. During normal operation, a high-pressure disturbance variable is produced by a pressure regulating valve on the high-pressure side, acting as an additional pressure control element, via which fuel is re-directed from the high-pressure accumulator into a fuel reservoir, the at least one pressure regulating valve being controlled, during normal operation, based on a set volumetric flow rate for the fuel to be re-directed. A temporal development of the set volumetric rate is sensed and the set volumetric flow rate is filtered, a time constant for the filtering of the set volumetric flow rate being selected as a function of the sensed temporal development.

A control device is applied to a fuel supply system including a fuel pump that rotates an impeller in a housing and pumps fuel from a fuel tank and a fuel pipe in which fuel discharged from the fuel pump flows. The control device controls the fuel pump. The control device includes an execution device and a storage device that stores a program of a process which is performed by the execution device. In the control device, the execution device performs a coping process of increasing an amount of operation of the impeller when the impeller is deformed and interference with the housing is detected in comparison with a case in which the interference is not detected.

Electronic fuel injection for an internal combustion engine maintains an operator-specified air-to-fuel ratio during engine operations in high-speed, high-volume, mixed fuel applications. A microprocessor-based controller executes a program stored in memory to calculate a fuel flow value as a function of the specified air-to-fuel ratio and specified density ratio of mixed fuels. The controller outputs a control signal to a variable fuel flow relief valve and receives feedback from an engine fuel flow sensor. The controller adjusts the control signal until the feedback matches the fuel flow value. The program optimizes the fuel flow value by accounting for engine air flow, water vapor density, and dry air density effects in the calculation, based on signals received by the controller from various environmental sensors. The system has particular application in dragster engines that burn a mixture of nitromethane and methanol.