A method for operating a speed-controlled fluid pump includes: providing an electrical control current for the fluid pump; providing a maximum value for the electrical control current, which maximum value corresponds to a maximum permissible pressure at an outlet side of the fluid pump; providing a threshold value for the control current, the threshold value corresponding to a further maximum permissible pressure at the outlet side of the fluid pump and is predefined in dependence upon at least one boundary condition, the threshold value being less than the maximum value for the electrical control current; and controlling the fluid pump with not more than the threshold value for the control current, if it has been determined that the at least one boundary condition holds, so as to limit the pressure at the outlet side of the fluid pump to a value provided for the at least one boundary condition.

When a rotational speed of an engine is higher than a predetermined rotational speed, a low-pressure fuel injection valve is controlled through the use of a fuel injection time based on an estimated fuel pressure in a low pressure supply pipe and a target fuel injection amount. When the rotational speed of the engine is equal to or lower than the predetermined rotational speed, the low-pressure fuel injection valve is controlled through the use of a fuel injection time based on a detected fuel pressure input from the fuel pressure sensor from the issuance of a command to activate energization of a solenoid to the start of energization of the solenoid and a target fuel injection amount.

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.

A storage device is configured to store a first mapping that receives, as an input, a first input variable including a cam phase variable on present and past phases of a cam, and output a pulsating variable on a pulsating component. The execution device is configured to acquire the first input variable and estimate the pulsating variable by applying the acquired first input variable to the first mapping. Therefore, it is possible to estimate the pulsating variable without providing a low-pressure fuel pressure sensor by estimating a fuel pressure variable by applying the first input variable to the first mapping.

A fuel pressure estimation system estimates a fuel pressure variable on a fuel pressure in a supply pipe for an engine apparatus including an engine having a fuel injection valve, and a fuel supply device having a fuel pump that supplies the fuel in a fuel tank to the supply pipe, and includes a storage device and an execution device. The storage device stores a first mapping that receives, as an input, first input variables including a pump variable, a consumption flow rate variable on a consumption flow rate of the fuel, and a property variable on a property of the fuel, and outputs the fuel pressure variable. The execution device acquires the first input variables and estimates the fuel pressure variable by applying the first input variables to the first mapping.

A control system includes a controller. The controller counts the number of driving times of the high pressure fuel pump, which is the number of the reciprocating motions of the plunger based on a crank counter that is counted up at every predetermined crank angle. The controller stores a map in which a top dead center of the plunger is associated with a crank counter value, and store a crank counter value while an engine is stopped as a stop-time counter value. The controller calculates, referring to the map, the number of the crank counter values corresponding to the top dead center of the plunger between a crank counter value and the stop-time counter value, and set a calculated number as the number of driving times.

A method for measuring pressure of a gaseous fuel compressed in a feed system of an engine equipping a motor vehicle, by a pressure measuring device having an infrared quality sensor and an electronic control unit, the measuring method being characterized in that it consists in determining a corrected absorbance value of the fuel based on absorbance measurements performed by infrared analysis, at preset wavelengths, and in comparing the value to a nominal absorbance value, determined beforehand based on absorbance measurements performed at a nominal pressure after a pressure stabilization phase of the fuel and at the same said wavelengths, in order to determine the fuel pressure.

A pump health assessment system and a method for providing a pump health of a pump is disclosed. The method includes: determining that there is an imbalance in the pump; increasing pump flow from the pump; measuring a rail pressure of a fuel rail; determining if the rail pressure is substantially equal to an expected rail pressure profile; and in accordance with a determination that the rail pressure is not substantially equal to the rail pressure profile, outputting an indication of pump damage.

When a rotational speed of an engine is higher than a predetermined rotational speed, a low-pressure fuel injection valve is controlled through the use of a fuel injection time based on an estimated fuel pressure in a low pressure supply pipe and a target fuel injection amount. When the rotational speed of the engine is equal to or lower than the predetermined rotational speed, the low-pressure fuel injection valve is controlled through the use of a fuel injection time based on a detected fuel pressure input from the fuel pressure sensor from the issuance of a command to activate energization of a solenoid to the start of energization of the solenoid and a target fuel injection amount.

A fuel pressure estimation system estimates a fuel pressure variable on a fuel pressure in a supply pipe for an engine apparatus including an engine having a fuel injection valve, and a fuel supply device having a fuel pump that supplies the fuel in a fuel tank to the supply pipe, and includes a storage device and an execution device. The storage device stores a first mapping that receives, as an input, first input variables including a pump variable, a consumption flow rate variable on a consumption flow rate of the fuel, and a property variable on a property of the fuel, and outputs the fuel pressure variable. The execution device acquires the first input variables and estimates the fuel pressure variable by applying the first input variables to the first mapping.