A method of detecting failures of an engine control computer including at least: a hardware layer, a software layer comprising at least one activation cycle of the load m phase(s) of activation of said load with: actuation of the load, first timeout, deactivation of the load, second timeout. The method of detecting failures includes a measurement time window during which the following are carried out: an initialization of the measurement variables, detection of an actuation of the load, an action of reinitializing the engine control computer if at least one of the following conditions is valid: T1>T1_ref, T2<T2_ref, T3>T3_ref, T4<T4_ref.

A method for functional monitoring of an apparatus for variable setting of a cylinder compression in a reciprocating-piston internal combustion engine is described, including ascertaining a value of an engine parameter which is indicative of an engine position of the internal combustion engine at a defined cylinder compression; comparing the ascertained value with a further value of the engine parameter; and determining, depending on a result of the comparison, whether the apparatus for variable setting of the cylinder compression is functioning correctly.

Methods and systems are provided for diagnosing a degraded fuel injector delivering undesired additional fuel in a variable displacement engine. In one example, a method includes, responsive to an indication of a cylinder air-fuel imbalance, deactivating a subset of cylinders of a multi-cylinder engine, performing a power balance test to determine an output of each cylinder after a duration of deactivation, and indicating that a deactivated cylinder has a degraded fuel injector responsive to the output being lower than a threshold output.

A method is provided for monitoring the operation of intake valves of an internal combustion engine, where at least one or more cylinders of the engine have more than one intake valve, and adapted to operate in different modes where at least one of the intake valves for a particular cylinder can be selectively activated, or deactivated so as not to open during a firing sequence for the cylinder. The method includes a) monitoring the intake manifold air pressure; b) during a time window with respect to the intake phase for said respective cylinder, determining the condition of whether the manifold pressure drops by a threshold or to a particular threshold level; and c) determining the functionality of the intake valves dependent on the outcome of step b).

Methods and systems for evaluating whether or not a fuel amount that is greater than a threshold has been release to an engine via fuel injectors when the fuel injectors are commanded off are presented. In one example, an oxygen sensor is activated and engine cranking is prevented until a pumping current of the oxygen sensor is proportionate to a concentration of oxygen sensed via the oxygen sensor so that released fuel may be observed during engine starting.

The invention relates to a method for testing an electrically activated actuator in a fuel delivery device (10) of an internal combustion engine, wherein the electrical actuator is a controllable valve (15) that is arranged on the inlet side of a high-pressure pump (16). The high-pressure pump (16) conveys fuel into a fuel store (17) having a pressure controller (20). The fuel store (17) is connected to at least one injector (23). The method comprises the following steps: 1) increasing the rotational speed of the high-pressure pump (16), 2) activating the controllable valve (15) until the pressure in the fuel store (17) has reached a first low pressure level, 3) changing the supply of current to the controllable valve (15) by a first specified value such that the controllable valve (15) is opened further and simultaneously maximizing an injection amount by means of the at least one injector (23) until the pressure in the fuel store (17) has reached a first threshold value, 4) activating the controllable valve (15) until the pressure in the fuel store (17) has reached the first low pressure level again, 5) determining a further quantity, which depends on the low pressure level and a maximum value of the pressure that was reached in the fuel store (17).

The subject matter of this specification can be embodied in, among other things, a method for characterizing a fluid injector that includes receiving a collection of waveform data, identifying a pull locus, determining a detection threshold level value, identifying a first subset of the collection of data representative of a selected first electrical waveform of the collection of electrical waveforms, identifying an opening value, identifying a representative closing value, identifying an anchor value, identifying a second subset of the collection of data based on the collection of data, the pull locus, the first subset, and the opening value, identifying a maximum electrical value, identifying an opening locus based the collection of data, the anchor value, and the maximum electrical value, identifying a hold value, and providing characteristics associated with the fluid injector comprising the pull locus, the opening locus, the hold value, the anchor value, and the representative closing value.

A drive system for driving a motor vehicle has an internal combustion engine and an operating mode coordination device for determining and controlling the operating mode of the internal combustion engine. The drive system has a function coordination device for coordinating secondary functions of the drive system, the function coordination device being designed for generating, based on the coordination of the secondary functions, an operating mode request for the operating mode coordination device for controlling the operating mode of the internal combustion engine, and transmitting it to the operating mode coordination device. The invention further relates to a motor vehicle having a drive system, and a method for operating a drive system of a motor vehicle.

Systems and methods for determining operation of a cylinder deactivating/reactivating device are disclosed. In one example, a warm engine is rotated without being supplied fuel to determine the presence or absence of valve actuator degradation. Degraded valve actuators may be determined when there is a lack of a temperature rise in the engine exhaust system.

A controller of an engine performs a failure diagnosis process for an injection valve. The failure diagnosis process increases a misfire count of the engine when a variation in rotation of the engine is equal to or greater than a predetermined variation in every predetermined cycle, and determines that the injection valve has a failure when the misfire count is equal to or greater than a first predetermined number of times over a predetermined time period. The controller determines that the multi-cylinder engine is in a predetermined load operation cycle if a volume efficiency of the multi-cylinder engine is less than a reference value, and the controller determines whether continuation of the injection mode is needed based on a comparison of the misfire count and a second predetermined number of times, wherein the second predetermined number of times is less than the first predetermined number of times.