A fuel property determining device for an engine is provided, the device retarding a fuel injection timing and determining a fuel property based on a combustion variation of the engine caused by the retarding. The device includes a processor configured to control a parameter related to combustibility so as to degrade a combustion state before the fuel injection timing is retarded, the parameter being different from the fuel injection timing.

A diagnostic test is conducted by operating an engine-generator set at a plurality of reduced speeds. At each of those speeds, operating parameters of the engine are sensed and analyzed to detect an unsatisfactory operating condition. For example, such operating parameters may include speed of the engine-generator set, engine oil pressure and level, engine temperature, coolant level, and battery voltage. When a transition in engine speed occurs, a throttle test also may be conducted to measure how quickly and smoothly the engine reaches the new speed. After the engine reaches the normal operating speed, the generator is activated to produce electricity. One or more characteristic of that electricity, such as voltage, current and frequency, are sensed and evaluated to detect an unsatisfactory operating condition.

A method of controlling a vehicle engine comprising estimating a value for the actual engine torque, comparing this with a further calculated (expected) torque value, and controlling the engine consequent to said comparing, the value for the actual engine torque being determined from the following steps: a) from a crankshaft signal, providing a plot or signal indicative of instantaneous crankshaft speed; b) differentiating said plot or signal indicative of instantaneous crankshaft speed with respect to time to determine acceleration values; c) within a crankshaft/time interval, determining a maximum and a minimum acceleration value from step b); d) determining the difference between said maximum and minimum acceleration values; e) determining a torque value dependent on said difference from step d).

Systems and methods for detecting at least one non-functional combustion chamber of an engine comprising a plurality of combustion chambers are described herein. In response to detecting a partial output power loss of the engine, one of the plurality of combustion chambers is assessed by monitoring an engine parameter indicative of an output power of the engine, determining whether a change in the engine parameter has occurred, when the change has occurred, determining that the combustion chamber is functional, and when no change has occurred, determining that the combustion chamber is non-functional and discontinuing fuel injection to the non-functional combustion chamber.

A method for diagnosing an engine in a vehicle, the method comprising: initiating a diagnostic test of the engine, disabling a cylinder of the engine, measuring a parameter indicative of performance of the engine, re-enabling the cylinder, comparing the parameter to reference data, assessing a status of the cylinder based on the comparison, and generating a diagnostic result based on the status of the disabled cylinder.

The disclosure relates to a method for identifying a change in the operating behavior of a crankshaft drive of a motor vehicle. In particular, the disclosure relates to a method for identifying error states of a torsional-vibration damper in the crankshaft drive, such as a jamming or slipping of a secondary mass of the torsional-vibration damper. The crankshaft drive comprises a crankshaft, a pulse generator that rotates when the crankshaft is in operation and a fixed sensor device, which generates a rotational speed signal N as a function of the rotational speed of the pulse generator. The method comprises the following steps: detecting a current rotational speed signal N.sub.akt of the sensor device during operation of the crankshaft drive; filtering the current rotational speed signal N.sub.akt using a bandpass filter that has at least one first passband range D1 comprising a first center frequency f1; comparing the filtered current rotational speed signal N.sub.akt with a reference signal N.sub.ref stored in a memory; and identifying a change in the operating behavior of the crankshaft drive on the basis of the comparison of the filtered current rotational speed signal N.sub.akt with the reference signal N.sub.ref. The disclosure further relates to a vehicle, such as a commercial vehicle, having a control device which is configured to perform a method of this kind.

A method and system for measuring, determining and/or analyzing the cranking RPM of a vehicle is provided. The system measures the voltage of at least a portion of a vehicle's electrical system to determine high and/or low voltage time periods during at least a portion of a starting or cranking cycle. The time between high and/or low voltage points can then be used, along with the number of cylinders in the vehicle, to determine the cranking RPM of the vehicle. The system may include a load module and a control module that are removably coupled to one another in first and second configurations.

A vehicle control device for a vehicle, the vehicle including a rotation lock mechanism preventing rotation of a coupling portion on the engine side of the rotating member in at least one direction, and an engine rotation speed sensor detecting a rotation speed of the engine, includes: a characteristic detecting portion detecting at least a torsional rigidity as the rotational characteristic by applying a torque to the rotating member from the electric motor to measure a twist angle of the rotating member while the rotation of the coupling portion is prevented by the rotation lock mechanism; and an engine rotation filtering portion calculating an actual resonance frequency based on the torsional rigidity detected by the characteristic detecting portion and filtering an engine rotation speed signal supplied from the engine rotation speed sensor to attenuate a vibration component of the actual resonance frequency in the engine rotation speed signal.

An anomaly diagnosing apparatus is adapted for a cooling device in an internal combustion engine. The apparatus is configured to execute an enlarging process, a rate calculating process, and an anomaly determining process. The enlarging process includes enlarging the cross-sectional area of the flow passage between an inner channel and an outer channel in the cooling device. The rate calculating process includes calculating a reference rate for a rate of rise of temperature of cooling water. The anomaly determining process includes determining that an anomaly is present in the check valve if a rate of rise of a detection value of cooling water temperature is smaller than the reference rate. The rate calculating process includes calculating the reference rate such that the reference rate has a smaller value in a case where the enlarging process is executed than in a case where the enlarging process is not executed.

An object is to carry out an abnormality diagnosis for a variable compression ratio mechanism without adding any special hardware configuration for estimating a compression ratio. An abnormality diagnostic device for a variable compression ratio mechanism adapted to be applied to an internal combustion engine comprises a controller configured to calculate a predetermined rotational speed difference which is a rotational speed difference, between an engine rotational speed at a predetermined crank angle before or after compression top dead center and an engine rotational speed in the vicinity of the compression top dead center for a predetermined cylinder at the time of carrying out fuel cut processing, set a reference range of the predetermined rotational speed difference, and make a diagnosis that abnormality has occurred in the variable compression ratio mechanism when the predetermined rotational speed difference is out of the reference range.