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.

Methods and systems are provided for diagnosing an in-range error of a pressure sensor arranged downstream of a lift pump in a fuel system of a vehicle. In one example, a method may include performing feedback control of the lift pump based on output of the pressure sensor, monitoring the pressure sensor output for flattening during the application of the voltage pulses, and adjusting operation of the fuel system depending on whether the pressure sensor output flattens for at least a threshold duration, which is indicative of an in-range error. The method may further include dynamically learning a setpoint pressure of a pressure relief valve of the fuel system and a fuel vapor pressure within the fuel system by monitoring pressure sensor output while adjusting the duty cycle of voltage pulses applied to the lift pump.

Methods and systems are provided for diagnosing an in-range error of a pressure sensor arranged downstream of a lift pump in a fuel system of a vehicle. In one example, a method may include performing feedback control of the lift pump based on output of the pressure sensor, monitoring the pressure sensor output for flattening during the application of the voltage pulses, and adjusting operation of the fuel system depending on whether the pressure sensor output flattens for at least a threshold duration, which is indicative of an in-range error. The method may further include dynamically learning a setpoint pressure of a pressure relief valve of the fuel system and a fuel vapor pressure within the fuel system by monitoring pressure sensor output while adjusting the duty cycle of voltage pulses applied to the lift pump.

An engine includes a low-pressure delivery pipe that stores fuel to be injected from port injection valves, a feed pump that supplies the fuel to the low-pressure delivery pipe, a high-pressure delivery pipe that stores the fuel to be injected from in-cylinder injection valves, a high-pressure pump driven in response to rotation of the engine, and a fuel pressure sensor that detects a pressure of the fuel stored in the low-pressure delivery pipe. An engine ECU controls the feed pump based on a detection value from a fuel pressure sensor, and when the engine ECU executes an abnormality diagnosis of the fuel pressure sensor, the engine ECU increases a rotational speed of the engine to be higher than a rotational speed when the engine ECU does not execute an abnormality diagnosis of the fuel pressure sensor. This improves the accuracy of an abnormality determination of the fuel pressure sensor.

A method for diagnosing a measurement of a pressure difference. The measurement is carried out with a measuring arrangement for a component of an exhaust gas device, the input of which is connected to a first exhaust gas pipe and the output of which is connected to a second exhaust gas. The measuring arrangement is provided with a pressure difference measuring device and with a first and second pressure measurement point, which are connected to the pressure difference measuring device for measuring the pressure difference between a pressure measured at the first pressure measurement point and at the second pressure measured at the second pressure measurement point. The pressure difference between the two pressure measurement points is measured with a pressure difference between measuring device.

A method is disclosed for diagnosing the reliability of a pressure sensor disposed in a fuel rail of an internal combustion engine. A control cycle is executed to measure a value of a fuel rail pressure with the pressure sensor, determine a first and a second threshold value of the fuel rail pressure, identify the measured value of the fuel rail pressure as reliable when the measured value is inside an interval of values ranging from the first threshold value to the second threshold value, and identify the measured value of the fuel rail pressure as unreliable when the measured value is outside that interval. The first and the second threshold values may be determined on the basis of a last reliable value of the fuel rail pressure.

Methods and systems are provided for conducting a fuel tank pressure transducer rationality test diagnostic procedure in vehicles with sealed fuel tanks. In one example, vehicle-to-vehicle (V2V) or vehicle-to-infrastructure-to-vehicle (V2I2V) technology may be utilized to obtain fuel tank pressure transducer data from a select crowd of vehicles, where the select crowd may be based on the vehicles in the select crowd experiencing similar ambient temperature and weather as the vehicle being diagnosed. In this way, FTPT data from vehicles in the select crowd may be compared to FTPT data in the vehicle being diagnosed, in order to indicate whether the FTPT in the vehicle being diagnosed is functioning as desired, where such a diagnostic can be performed without unsealing the fuel tank on either the vehicle being diagnosed or the vehicles in the select crowd, and which may thus reduce undesired evaporative emissions.

A method for operating a common-rail system of a motor vehicle that includes a common-rail-pressure sensor configuration having at least two signal paths, and that can be operated at a maximally permissible common-rail pressure and at a minimally permissible common-rail pressure. Sensor signals are read out in each case in response to a pressure measurement in a common rail of the common-rail system via the at least two signal paths, and a signal deviation value is ascertained that characterizes a deviation between the pressure values that are each determined on the basis of the sensor signals. The method includes reducing the maximally permissible common-rail pressure by a correction value to a maximally permissible emergency common-rail pressure and/or increasing the minimally permissible common-rail pressure by a correction value to a minimally permissible emergency common-rail pressure in response to the signal deviation value exceeding a predefined value.

A first computer-implemented diagnostic method can run in response to an imminent deceleration fuel cutoff (DFCO) event. A second computer-implemented diagnostic method can run on engine shutdown. Both diagnostic methods involve controlling fuel injectors and a fuel pump to make the fuel rail pressure change from a desired minimum to a desired maximum. Measurements from the fuel rail pressure sensor at these endpoints can then be used to detect a fault of the fuel rail pressure sensor. One or both diagnostic methods can be implemented.

A setting unit which is connected to an intake passage and defines a reference value for a pressure in a passage through which gas flows, an accumulating unit which integrates a difference between the reference value and the pressure from a point in time when the pressure falls below the reference value and acquires an cumulative value, and a diagnosis unit which diagnoses an abnormality of the passage based on the cumulative value, wherein when there is no peak in the pressure, the setting unit sets the reference value based on a state of the internal combustion engine, and when there is a peak in the pressure, the setting unit sets the peak as the reference value in the abnormality diagnosis device.