A control system of an internal combustion engine includes an electronic control unit. The electronic control unit is configured to: (i) obtain a detection value of a fuel pressure sensor at fixed sampling time intervals; (ii) calculate a center fuel pressure value of a pulsation of the fuel pressure, based on at least a first latest fuel pressure value and a second latest fuel pressure value as detection values of the fuel pressure sensor, (iii) calculate an amplitude of the pulsation of the fuel pressure, based on at least the second latest fuel pressure value and the first latest fuel pressure value; (iv) calculate an initial phase of the pulsation of the fuel pressure, based on at least one of the second latest fuel pressure value and the first latest fuel pressure value, and (v) predict a fuel pressure value corresponding to the crank angle, based on a predetermined formula.

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 viscosity of a fuel with the aid of an electric fuel pump which is integrated into a fuel circuit including an overflow valve which includes a permanently open discharge channel, a fuel supply and delivery being adjusted with the aid of the electric fuel pump in the fuel circuit at a specific pressure and the viscosity of the fuel being ascertained by taking into account a delivery rate of the electric fuel pump.

A control device for an internal combustion engine is equipped with an electronic control unit. The electronic control unit is configured to: i) calculate amplitudes of respective waves, respectively, originating from a plurality of factors that causes fuel pressure pulsation within a low-pressure fuel passage, vibration frequencies of the respective waves within a crank angle range of 360 degrees, initial phases of the respective waves, and central fuel pressure values of the respective waves; and ii) predict a fuel pressure value at an arbitrary crank angle according to a model formula showing a synthesized wave obtained by synthesizing the respective waves, on a basis of the amplitudes, the vibration frequencies, the initial phases, and the central fuel pressure values of the respective waves calculated.

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 control device for an internal combustion engine includes a throttle valve actuator and circuitry. The circuitry is configured to calculate, based on a target intake air amount, a target recirculated amount of recirculated exhaust gas that is recirculated to an intake passage through an exhaust gas recirculation device, calculate a corrected target recirculated amount based on the target recirculated amount and an exhaust gas recirculated amount change delay in a change in a recirculated amount of the recirculated exhaust gas, calculate a target intake pressure based on the target intake air amount and the corrected target recirculated amount, calculate a target opening degree of the throttle valve based on the target intake air amount and the target intake pressure, and control the throttle valve actuator to drive the throttle valve such that an opening degree of the throttle valve is to be equal to the target opening degree.

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 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.

The invention provides a device and a method for determining a pressure of a fuel (19) which is to be injected into a combustion chamber (23) via a controllable closure element (11) of a solenoid valve (1), wherein the method comprises: generating a current flow (i) through a coil (3) of the solenoid valve (1) in order to generate a magnetic field, in order to generate a magnetic force acting on an armature (9), which magnetic force shifts the armature (9) in the direction of the opening of the closure element (11), determining a magnitude of a magnetic flux () of the magnetic field before or when a first state (I) at which the armature starts to shift the closure element is reached, and determining a magnitude of the pressure on the basis of the determined magnitude of the magnetic flux.

A method according to the invention for checking the plausibility of the function of a pressure sensor in an injection system of an internal combustion engine includes acquiring a calibrated actuation profile, by which peak current values for opening at least one electrically actuatable injection valve are assigned to existing internal pressures. An existing internal pressure is measured in the form of an actual sensor pressure value by the pressure sensor. The method includes obtaining the electrical peak current value corresponding to the measured sensor pressure value from a calibrated actuation profile, such that the corresponding electrical peak current value acquired in this way is applied to the injection valve. Subsequently, an opening state of the injection valve is monitored in reaction to the applied electrical peak current value, and a functional state of the pressure sensor is assigned as a function of the opening state of the injection valve.