A method for operating an internal combustion engine with a motor having a number of cylinders and an injection system having a common rail with a number of injectors assigned to the cylinders and similar high pressure components, which is designed to hold fuel from the common rail for the injector, wherein the method has the steps: injecting fuel from the common rail into a cylinder by way of an injector, determining a fuel pressure for a high-pressure component, in particular the common rail, the injector and/or the individual reservoir, having at least one high-pressure sensor measuring the fuel pressure. Provision is made for a defect in the high-pressure sensor to be detected in that a check is made as to whether magnitude of the high-pressure control deviation (ep) during a predetermined time interval (t.sub.Limit1.sup.SD, t.sub.Limit2.sup.SD, t.sub.Limit3.sup.SD) exceeds a predetermined limiting value (e.sub.Limit1.sup.SD, e.sub.Limit2.sup.SD, e.sub.Limit3.sup.SD).

A pressure sensor malfunction determination device for a fuel tank includes a fuel tank that stores fuel, a canister that absorbs an evaporated fuel gas and includes a drain port opened to atmosphere, an evaporation path communicating with the canister and fuel tank, a purge gas path communicating with an engine inlet system and the canister, a pressure sensor that detects a pressure, a solenoid valve that opens/closes the evaporation path, and a control unit that controls an opening/closing state of the solenoid valve. When the fuel tank pressure is one of predetermined positive and negative pressure states, the control unit performs valve-opening control on the solenoid valve. The control unit includes a pressure sensor malfunction determination unit that, when an output value of the pressure sensor detected under an atmospheric pressure condition corresponds to a pressure other than the atmospheric pressure, determines that the pressure sensor is malfunctioning.

A controller includes a soak timer, a nonvolatile memory, and a determining section. The determining section is configured to perform a rationality check on a condition that a performance condition is met. The determining section is also configured to make the performance condition strict when an obtained index value of a vehicle outside temperature, that is obtained when an elapsed amount of time reaches a specified amount of time, and the determining section is activated, is higher than a stored index value of the vehicle outside temperature stored in the nonvolatile memory.

A fuel supply system with a fuel pressure sensor includes a failure detection part which sets a first threshold value and a second threshold value which are deviated by first (smaller) and second (larger) predetermined values with respect to a target fuel pressure respectively; immediately detects a possibility of failure in the case where an absolute value of a difference between an output value of the fuel pressure sensor and the target fuel pressure exceeds an absolute value of a difference between the second threshold value and the target fuel pressure; and determines a failure of the fuel pressure sensor in the case where the absolute value of the difference between the output value of the fuel pressure sensor and the target fuel pressure has been exceeding an absolute value of a difference between the first threshold value and the target fuel pressure for a specified time or longer.

A controller for vehicle is provided. A determining section obtains fuel pressure in a delivery pipe and performs a rationality check for determining whether the obtained fuel pressure is within a normal range. The determining section shifts the normal range toward a high pressure side when a second index value of a vehicle outside temperature is higher than a first index value as compared with when the second index value is not higher than the first index value. The second index value is obtained when the determining section is activated. The first index value is stored in a nonvolatile memory before a main switch is turned off so that power supply is stopped.

A failure diagnosis device for an in-cylinder pressure sensor is provided, which includes an in-cylinder pressure sensor, and an engine controller comprised of circuitry configured to execute a diagnosis module into which a signal of the sensor is inputted, to diagnose a failure of the sensor based on the signal. The diagnosis module includes a reading module configured to read the signal of the sensor within a specific crank angle range, a reference phase determining module configured to determine a reference phase that is a phase of a pressure change accompanying a volume change of the combustion chamber, and a failure determining module configured to determine that the sensor has failed, when the failure determining module determines a phase of the read signal of the sensor is delayed by an amount exceeding a predefined threshold from the determined reference phase.

An anomaly diagnostic device for an onboard internal combustion engine includes a parameter deriving unit and a leaking anomaly diagnostic unit. The parameter deriving unit is configured to derive a determination parameter such that, when a PCV pressure sensor value that indicates a pressure detected by a PCV pressure sensor is less than an atmospheric pressure, a value of the determination parameter increases as the difference between the PCV pressure sensor value and the atmospheric pressure increases. The leaking anomaly diagnostic unit is configured to perform a leaking anomaly diagnostic process that diagnoses that there is an anomaly at a portion of a blow-by gas passage that is closer to an intake passage than to a connection portion of the PCV pressure sensor when the determination parameter derived when an intake air amount changes is less than a threshold.

A failure diagnosis system for an in-cylinder pressure sensor is provided, which includes an in-cylinder pressure sensor, a fuel injection valve, an engine controller including an engine control module and a diagnosis module. The engine control module controls the fuel injection valve to stop the supply of fuel to the engine, when a fuel cut condition is satisfied while the automobile travels. The diagnosis module includes a limiting module configured to limit an execution of the failure diagnosis of the in-cylinder pressure sensor until the diagnosis module determines that a given period has lapsed after the stop of fuel supply to the engine. The diagnosis module reads a signal of the in-cylinder pressure sensor when the given period has lapsed after the stop of the fuel supply to the engine, and diagnoses the failure of the in-cylinder pressure sensor based on the read signal of the in-cylinder pressure sensor.

A control system includes a controller. The controller acquires a crank counter value each time a fixed time elapses. The controller calculates the number of the crank counter values corresponding to the top dead center of the plunger between a previously acquired crank counter value and a currently acquired crank counter value with reference to the map each time the crank counter value is acquired and calculate the number of driving times of the high pressure fuel pump by integrating the calculated number.

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.