Disclosed is a method for estimating an angular position of top dead center for a high-pressure fuel injection pump that forms part of a system for injecting fuel into a motor vehicle engine, the pump including at least one piston moving in a chamber between the top and the bottom dead center, the pump being equipped with a digital control valve for controlling a quantity of fuel, an electrical current being applied to the digital valve as it closes then removed in order to open the digital valve, a movement of the digital valve in the direction of opening creating an induced current which makes it possible to detect a position of start-of-opening of the digital valve. An instant at which the pump piston passes through top dead center is estimated as a function of an instant at which the position of start-of-opening of the digital valve appears.

A method for ascertaining a setpoint value for a manipulated variable for the actuation of a low-pressure pump in a fuel-supply system for an internal combustion engine having a high-pressure accumulator and a high-pressure pump, the high-pressure pump being operated in a full delivery mode, and the low-pressure pump being actuated so that a pressure provided by the low-pressure pump is reduced, and the setpoint value at which a dip in a delivery quantity of the high-pressure pump is detected is ascertained while taking into account an actuation value of the manipulated variable.

A fluidic subsystem disposed on a vehicle includes an electric motor, a motor driver, and a fluidic pump that is disposed in a fluidic circuit that is monitored by a pressure sensor. A controller includes an instruction set that is executable to dynamically observe operation of the fluidic subsystem, from which it determines a plurality of observed parameters associated with the operation of the fluidic subsystem and a plurality of estimated parameters associated with the fluidic subsystem. A plurality of fault isolation parameters are determined based upon the observed parameters and the estimated parameters, and a fault in the fluidic subsystem is isolated based upon the fault isolation parameters. The isolated fault is communicated via the controller.

A method of controlling a low-pressure fuel pump may include: identifying a fuel consumption amount of the low-pressure fuel pump in response to a feedforward fuel control; determining a motor driving base duty based on the fuel consumption amount; and identifying a target fuel pressure based on the pressure of fuel.

A method of preventing an engine stall of a vehicle having a fuel injection device for pressurizing fuel stored in a fuel tank by a high-pressure fuel pump to transmit the fuel to a common rail, and injecting the fuel temporarily stored in the common rail into an engine through an injector may include steps of determining whether or not a drift occurs in an output signal of a high-pressure fuel pressure sensor for measuring fuel pressure at a downstream side of the high-pressure fuel pump, and performing a fuel pressure control by replacing a high-pressure fuel pressure value with a predetermined pressure value based on the output signal of the high-pressure fuel pressure sensor.

A fuel pump controller performs a feedback control of an actual fuel pressure of a feed pump to a command fuel pressure which is from an external element. The pump controller changes a gain for the feedback control to a value larger than a minimum value of the gain in response to an acceleration command information which is to accelerate a vehicle by using an internal combustion engine.

Systems and methods are provided for operating a port fuel and direct injection fuel system of a rolling variable displacement engine (rVDE). In one example, a method may include selecting between controlling a lift pump of the fuel system to output fuel at a mechanically limited pressure and controlling the lift pump to output fuel at a pressure lower than the mechanically limited pressure based on whether port fuel injection is used. In this way, the lift pump may be controlled without feedback from a pressure sensor, reducing system costs, while electrical power consumption increases due to operating the lift pump to output fuel at the mechanically limited pressure are minimized due to the rVDE technology, which reduces port fuel injection usage.

Methods and systems are provided for calibrating engine port injectors. After pressurizing a low pressure fuel rail, a lift pump may be disabled and port injector variability may be correlated with a measured fuel rail pressure drop at each port injection event by sweeping injection pressure while maintaining injection voltage, and then sweeping injection voltage while maintaining injection pressure. A port injector variability map learned as a function of injection voltage and injection pressure is then transformed into a map learned as a function of injection current and injection pressure by accounting for injector variability caused due to changes in injector temperature.

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 lower limit setting portion of a fuel pump control system sets a lower limit value depending on an engine operating mode. For example, it sets a duty ratio of 0% as the lower limit value, when the engine operating mode is in a STOP mode in a turned-on condition of an ignition switch. A duty-ratio calculating portion carries out a feedback control in order that an actual fuel pressure comes closer to a target fuel pressure by use of the lower limit value and calculates a duty ratio for driving a fuel pump by the feedback control. An abnormal condition determining portion determines an abnormal condition based on the duty ratio and pump current. The abnormal condition determining portion further determines based on a remaining fuel amount whether the abnormal condition is caused by a disconnection or whether the abnormal condition is caused by an idling operation of the fuel pump due to fuel shortage.