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 method for starting a direct-injection internal combustion engine of a vehicle includes: rotating the high-pressure injection pump by a starter; measuring fuel pressure delivered by the pump, taken at two successive compression top dead centers of the pump operating in maximum output mode; establishing the pressure gradient of the fuel, on an angular reference system, based on the two successive pressure measurements; comparing the established gradient with a predefined bijective table that respectively matches a plurality of quantities of fuel to be injected and a plurality of pressure gradients; and adapting the quantity of fuel injected during the starting phase before the engine reaches steady operating speed, depending on the result of the comparison, in order to inject a quantity of fuel that corresponds, in the predefined bijective table, to the established pressure gradient, upon authorization of the first injection given by the engine control unit.

The invention relates to a method for testing an electrically activated actuator in a fuel delivery device (10) of an internal combustion engine, wherein the electrical actuator is a controllable valve (15) that is arranged on the inlet side of a high-pressure pump (16). The high-pressure pump (16) conveys fuel into a fuel store (17) having a pressure controller (20). The fuel store (17) is connected to at least one injector (23). The method comprises the following steps: 1) increasing the rotational speed of the high-pressure pump (16), 2) activating the controllable valve (15) until the pressure in the fuel store (17) has reached a first low pressure level, 3) changing the supply of current to the controllable valve (15) by a first specified value such that the controllable valve (15) is opened further and simultaneously maximizing an injection amount by means of the at least one injector (23) until the pressure in the fuel store (17) has reached a first threshold value, 4) activating the controllable valve (15) until the pressure in the fuel store (17) has reached the first low pressure level again, 5) determining a further quantity, which depends on the low pressure level and a maximum value of the pressure that was reached in the fuel store (17).

Fuel in a fuel tank is supplied by a low-pressure pump to intake passage injectors mounted on an intake manifold via a low-pressure fuel supply pipe and a low-pressure fuel distribution pipe. A high-pressure pump is provided on the low-pressure fuel supply pipe. The pressure of the fuel is boosted by the high-pressure pump, and then is supplied to in-cylinder injectors via a high-pressure fuel distribution pipe. In an intake passage injection (MPI) mode, excitation of a solenoid is stopped and operation of an electromagnetic spill valve is stopped so as reduce vibration and noise caused by the seating of the electromagnetic spill valve in a valve seat.

A microcomputer determines a presence of an abnormality of a fuel injection quantity control device based on a comparison between a required injection quantity as a command value for the amount of a fuel injected from an injector in one engine cycle and a total monitor injection quantity as a total value of monitor injection quantities obtained from an energization time monitor value of the injector for each fuel injection in the one engine cycle. The microcomputer removes a micro-injection correction amount from the monitor injection quantity when the monitor injection quantity is below a determination value and executes a removal processing in which the removal of the micro-injection correction amount from the monitor injection quantity is not performed when the monitor injection quantity is at least the determination value. The total value of the monitor injection quantities after the removal processing is regarded as the total monitor injection quantity.

Provided is a high-pressure fuel supply device for an internal combustion engine, said device being capable of suppressing noise from collisions of a plunger rod and an air intake valve. A high-pressure fuel pump 108 comprises an intake valve, a plunger rod that is formed as a separate element from the intake valve, an elastic member that biases the plunger rod in the valve-opening direction of the intake valve, and a solenoid that draws the plunger rod in the valve-closing direction of the intake valve when supplied with electricity. A control device 101 has a first control unit that applies a first current to the solenoid in order to close the intake valve, and a second control unit that applies a second current to the solenoid before the plunger rod collides with the intake valve due to the biasing force of the elastic member.

A controller for an internal combustion engine including a fuel pressure control processor that controls a fuel pressure at a target fuel pressure, an instruction value calculating processor that calculates a peak instruction value, an upper limit guard processor that executes a guard process on the peak instruction value, an energizing processor that energizes the coil based on the peak instruction value that has undergone the guard process, a convergence determination processor that determines whether or not the detected fuel pressure has converged on the target fuel pressure, and a decreasing processor that decreases the upper limit guard value to a lower value when the fuel pressure has converged on the target fuel pressure than when the fuel pressure has not converged on the target fuel pressure.

Methods and systems are provided for operating a fuel system comprising two lift pumps. In one example, a method may comprise adjusting operation of a first lift pump to achieve a desired fuel rail pressure. The method may comprise powering on a second lift pump to achieve the desired fuel rail pressure when operating only the first lift pump is not sufficient to achieve the desired fuel rail pressure.

Methods and systems for adjusting fuel injector operation according to changes in fuel pressure during inter-injection periods are described. The inter-injection period may be before and after fuel is injected to an engine. The methods and systems described herein may be suitable for direct and port fuel injectors.

Various methods and systems are provided diagnosing a valve. In one example, a system comprises a valve configured to regulate a fuel flow, and a controller configured to determine degradation of the valve based on an initial opening characteristic of the valve.