A misfire detection device includes processing circuitry configured to execute a stopping process stopping combustion control of an air-fuel mixture in one or more cylinders and a determination process determining whether a misfire has occurred based on a value of a determination subject rotation fluctuation amount, that is, a rotation fluctuation amount of a determination subject cylinder for misfire. A comparison subject rotation fluctuation amount is a rotation fluctuation amount corresponding to a crank angle separated by a predetermined angular interval from a crank angle corresponding to the determination subject rotation fluctuation amount. The determination process includes a process determining the misfire based on a value of the determination subject rotation fluctuation amount when the predetermined angular interval equals an angular interval between crank angles at which compression top dead center appears in the one or more of the cylinders and the determination subject cylinder during the stopping process.

Various embodiments include a method for actuating a camshaft adjuster of an internal combustion engine, in which a current is generated in an electric motor of the camshaft adjuster comprising: measuring an instantaneous strength of the current; calculating a mean value of the measured strength of the current over a predefined elapsed time; measuring a temperature of the camshaft adjuster; comparing the mean value of the measured strength of the current to a threshold value obtained from a characteristic diagram stored in a memory based on the measured temperature and the predefined elapsed time; and reducing the current if the calculated mean value of the strength of the current is higher than the threshold value.

A multi-cylinder internal combustion engine is configured to perform an all-cylinder operation and a partial-cylinder operation. The ignition timing controller executes a process that sets a knock control amount and a knock learning value, a process that determines whether knocking is occurring, a process that updates a value of the knock control amount in accordance with whether knocking is occurring, a process that updates the knock learning value such that the knock learning value gradually approaches a knock control operated amount, a process that operates ignition timing of each cylinder based on the knock control amount and the knock learning value, and a process that limits update of the knock learning value such that a followability of the knock learning value to the knock control operated amount is lower during the partial-cylinder operation than during the all-cylinder operation.

A control device and a control method for variable valve timing mechanism according to the present invention obtains a first measurement of a rotational phase based on a rotational angle of the motor, obtains a second measurement of the rotational phase based on a relative relationship between a rotational angle of the crankshaft and a rotational angle of the camshaft, calibrates the first measurement based on the second measurement, obtains a derivative term proportional to a rate of change in a deviation between the first measurement and a target value, reduces change in derivative term when calibrating the first measurement based on the second measurement, and controls the motor based on a manipulated variable including the derivative term.

A method for predicting the combustion state of an engine sets the operating condition of the engine, calculates the temperature of a highest temperature portion of the cylinder before combustion based on the operating condition, calculates the combustion start timing based on the temperature of the highest temperature portion, calculates the temperature of a lowest temperature portion of the cylinder based on the operating condition and the combustion start timing, and calculates the combustion end timing based on the temperature of the lowest temperature portion. The method calculates the temperature of a wall surface layer portion located adjacent the wall surface in the cylinder based on state changes in a burned portion, an unburned portion, and the wall surface layer portion that constitute a combustion chamber inside of the cylinder, and applies the temperature of the wall surface layer portion as the temperature of the lowest temperature portion.

The invention relates to a method for diagnosing and/or controlling a reciprocating engine having a variable compression ratio, wherein the method comprises the working steps: determining (S30) a first value (U.sub.1,1, U.sub.1,2; Δ.sub.1) of a rotational irregularity parameter of a crankshaft (1) of the reciprocating engine; and determining (S60) a value of a compression ratio parameter for the reciprocating engine based on said first rotational irregularity parameter value.

An industrial vehicle work guide system is disclosed. An industrial vehicle work guide system according to an embodiment of the present invention includes: a memory configured to store engine used data, a driving time, a fuel consumption amount, and reference fuel efficiency; a display module configured to output a guide message; and an analysis module configured to calculate actual fuel efficiency by using the engine used data, the driving time, and the fuel consumption amount, compare the actual fuel efficiency with the reference fuel efficiency, and control the display module so that the display module outputs a guide message when the actual fuel efficiency is lower than the reference fuel efficiency.

A multi-cylinder internal combustion engine is configured to perform an all-cylinder operation and a partial-cylinder operation. The ignition timing controller executes a process that sets a knock control amount and a knock learning value, a process that determines whether knocking is occurring, a process that updates a value of the knock control amount in accordance with whether knocking is occurring, a process that updates the knock learning value such that the knock learning value gradually approaches a knock control operated amount, a process that operates ignition timing of each cylinder based on the knock control amount and the knock learning value, and a process that limits update of the knock learning value such that a followability of the knock learning value to the knock control operated amount is lower during the partial-cylinder operation than during the all-cylinder operation.

A device for a fuel system that makes a fuel available for an operation of an internal-combustion engine where the fuel system includes a fuel pump which conveys the fuel into a fuel accumulator and includes one or more injection nozzles which convey the fuel from the fuel accumulator to a working mixture of one or more cylinders of the internal-combustion engine includes an evaluation unit. The evaluation unit is configured to ascertain pressure data with respect to a physical pressure in the fuel accumulator during an operation of the fuel system at a sampling-time, ascertain a change in a reference pressure at the sampling-time with aid of a reference model of the fuel system, and detect a defect of the fuel system on a basis of the pressure data and on a basis of the change in the reference pressure.

A misfire detection device includes processing circuitry configured to execute a stopping process stopping combustion control of an air-fuel mixture in one or more cylinders and a determination process determining whether a misfire has occurred based on a value of a determination subject rotation fluctuation amount, that is, a rotation fluctuation amount of a determination subject cylinder for misfire. A comparison subject rotation fluctuation amount is a rotation fluctuation amount corresponding to a crank angle separated by a predetermined angular interval from a crank angle corresponding to the determination subject rotation fluctuation amount. The determination process includes a process determining the misfire based on a value of the determination subject rotation fluctuation amount when the predetermined angular interval equals an angular interval between crank angles at which compression top dead center appears in the one or more of the cylinders and the determination subject cylinder during the stopping process.