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.

Systems and methods are provided herein for tracking degradation of a high-pressure fuel pump. In one example, a fuel system controller is configured to receive an output pressure signal from a pressure sensor, transform the output pressure signal to the frequency domain to generate frequency content of the output pressure signal, and diagnose a condition of a fuel pump based at least in part on the frequency content of the output pressure signal, the fuel pump fluidly coupled to a fuel injector via a common fuel rail, and the fuel injector is operable to inject fuel to a cylinder of an engine.

A fuel delivery system for a vehicle engine and a method are provided. A first valve in parallel with a first fuel pump fluidly couples a fuel line to a fuel tank. A second valve in parallel with a second fuel pump fluidly couples a fuel rail to the fuel line. A controller opens the first and second valves during a vehicle key-off state to relieve pressure in the fuel rail and drain fuel into the fuel tank. A vehicle is provided with a fuel tank, and a valve fluidly coupling a fuel rail and a fuel tank. A controller opens the valve during a vehicle key-off state to drain fuel from the fuel rail into the fuel tank and relieve pressure in the fuel rail, and closes the valve in response to a predicted key-on event during the vehicle key-off state.

A control device for controlling an engine provided with a fuel pump including a pressurizing chamber, a plunger inserted into the pressurizing chamber and which changes a volume of the pressurizing chamber, and an on-off valve configured to open and close a suction port, is provided. When a pressurizing cycle consists of a period of pressurizing stroke in which the volume of the pressurizing chamber is reduced to allow fuel to be pressurized and a period of suction stroke in which the volume of the pressurizing chamber is increased to allow fuel to be drawn into the pressurizing chamber, a closing cycle of the on-off valve is controlled so that a ratio of the closing cycle to the pressurizing cycle becomes smaller in a second combustion mode where a partial compression-ignition combustion is performed than in a first combustion mode where SI combustion is performed.

Various methods and systems are provided for indexing an injector map and subsequently controlling fuel injection to an engine. In one embodiment, a method for the engine includes injecting fuel via activating an injector for a determined activation time, the activation time determined based on a commanded fuel value and a function of a modified pressure difference across an orifice of a nozzle of the injector, where the modified pressure difference is based on a difference between a rail pressure and peak cylinder pressure, the peak cylinder pressure scaled by a function of engine speed and injection timing and the pressure difference offset by a correction factor.

A control device for controlling an engine provided with a fuel pump including a pressurizing chamber, a plunger inserted into the pressurizing chamber and which changes a volume of the pressurizing chamber, and an on-off valve configured to open and close a suction port, is provided. When a pressurizing cycle consists of a period of pressurizing stroke in which the volume of the pressurizing chamber is reduced to allow fuel to be pressurized and a period of suction stroke in which the volume of the pressurizing chamber is increased to allow fuel to be drawn into the pressurizing chamber, a closing cycle of the on-off valve is controlled so that a ratio of the closing cycle to the pressurizing cycle becomes smaller in a second combustion mode where a partial compression-ignition combustion is performed than in a first combustion mode where SI combustion is performed.

A pressurized fuel injection system for an engine includes a pressure sensor in a low pressure rail, an electronic pressure regulator valve in flow communication with and downstream from the low pressure rail and in flow communication with and upstream from a fuel supply, and a controller configured to receive a pressure signal from the pressure sensor and to control the electronic pressure regulator valve in response to the pressure signal to maintain a target pressure in the low pressure rail.

A method is described for operating an electric fuel pump constituting a low-pressure pump in a fuel supply system for an internal combustion engine, having a high-pressure reservoir and a high-pressure pump, of a motor vehicle. The electric fuel pump is operated at least temporarily, during a time period during which the internal combustion engine is switched off during operation of the motor vehicle, with a minimum value for a control application variable for the electric fuel pump.

Methods and systems are provided for operating a lift pump of an engine fuel system. In one example, a method may comprise predicting when a fuel rail pressure will decrease below a threshold assuming that a lift pump remains off. The method may further comprise powering on the lift pump before the fuel rail pressure decreases below to the threshold to prevent fuel rail pressure from decreasing below the threshold.

A method for ascertaining a setpoint value for a manipulated variable for activating a low-pressure pump in a fuel supply system for an internal combustion engine, including a high-pressure accumulator and a high-pressure pump including a volume control valve, the low-pressure pump being activated in such a way that a pressure provided by the low-pressure pump is reduced across multiple intake phases, in which fuel delivered by the low-pressure pump is sucked in by the high-pressure pump via the volume control valve, the volume control valve being at least temporarily held in a closed position during each of the multiple intake phases, in which it may be opened from a side facing the low-pressure pump, and the setpoint value being ascertained, taking into account an activating value of the manipulated variable, in which a drop in the delivery rate of the high-pressure pump is detected.