Abstract: The invention relates to a method for operating a fuel injection system (1) for supplying a combustion engine of a vehicle with fuel, in which method the fuel is conveyed at high pressure with the aid of a high-pressure pump (2), fed to a high-pressure accumulator (3), and injected into a cylinder of the combustion engine with the aid of at least one injector connected to the high-pressure accumulator (3). In order to detect any damage to the drive of the high-pressure pump (3), according to the invention a) the pressure (P) in the high-pressure accumulator (3) is measured and, on the basis of the measured values, a pressure drop (?P) in the high-pressure accumulator (3) caused by an injection into a cylinder is determined, b) a maximum pressure gradient is determined during a pressure build-up phase following the injection, c) the determined pressure drop (?P) and the determined maximum pressure gradient are put into proportion.

Abstract: A method for operating an internal combustion engine is provided in which fuel is withdrawn from a high-pressure accumulator and injected into a combustion chamber of at least one cylinder of the internal combustion engine, the method including the steps of detecting under conditions of angular synchronism a pressure of the fuel in the high-pressure accumulator during a first injection into the at least one cylinder and during a later, second injection into the at least one cylinder; ascertaining a gradient of the detected pressure; ascertaining a frequency-transformed spectrum of the detected pressure and a frequency-transformed spectrum of the ascertained gradient; correcting the frequency-transformed spectrum of the detected pressure by the frequency-transformed spectrum of the ascertained gradient; and ascertaining a cylinder-individual injection quantity of fuel, which was injected into the at least one cylinder, from the corrected frequency-transformed spectrum of the detected pressure.

Abstract: A method for operating an internal combustion engine is provided in which fuel is withdrawn from a high-pressure accumulator and injected into a combustion chamber of at least one cylinder of the internal combustion engine, the method including the steps of detecting under conditions of angular synchronism a pressure of the fuel in the high-pressure accumulator during a first injection into the at least one cylinder and during a later, second injection into the at least one cylinder; ascertaining a gradient of the detected pressure; ascertaining a frequency-transformed spectrum of the detected pressure and a frequency-transformed spectrum of the ascertained gradient; correcting the frequency-transformed spectrum of the detected pressure by the frequency-transformed spectrum of the ascertained gradient; and ascertaining a cylinder-individual injection quantity of fuel, which was injected into the at least one cylinder, from the corrected frequency-transformed spectrum of the detected pressure.

Abstract: A method and a device for setting an afterglow temperature in a self-igniting internal combustion engine, the afterglow temperature being reduced in a defined operating state of the internal combustion engine until a modification of an operating parameter as a result of the reduction of the afterglow temperature is required in order to maintain the defined operating state, in particular in order to maintain the injected fuel quantity.

Abstract: A method for determining the quality of the fuel for an internal combustion engine, in particular a direct-injection internal combustion engine in a vehicle, which is characterized by the following be performed: the internal combustion engine is operated in idle mode under predefinable operating conditions, the curve of the injection quantity, necessary for idling, over the engine temperature is determined, and the fuel quality is inferred from the curve of the injection quantity over the engine temperature.

Abstract: A method and a device for setting an afterglow temperature in a self-igniting internal combustion engine, the afterglow temperature being reduced in a defined operating state of the internal combustion engine until a modification of an operating parameter as a result of the reduction of the afterglow temperature is required in order to maintain the defined operating state, in particular in order to maintain the injected fuel quantity.

Abstract: The invention relates to a method and a device for controlling an internal combustion engine for which, in the light of performance characteristics, control parameters for at least one control element (100) are specified. A parameter is determined which characterizes the uneven running.

Abstract: A method for determining the quality of the fuel for an internal combustion engine, in particular a direct-injection internal combustion engine in a vehicle, which is characterized by the following be performed: the internal combustion engine is operated in idle mode under predefinable operating conditions, the curve of the injection quantity, necessary for idling, over the engine temperature is determined, and the fuel quality is inferred from the curve of the injection quantity over the engine temperature.