Abstract: In a method and a device for operating an injection device (5) for an internal combustion engine, the injection device (5) includes injection valves (40), via which fuel is injected directly into combustion chambers (100) of the internal combustion engine. Mechanisms are provided for detecting misfirings (310), and for determining a fuel pressure (320). A mechanical fault of an injection valve (40) is detected when a misfire occurs in a cylinder (110) and the fuel pressure simultaneously drops below a threshold value (SW). An electrical fault in an injection device (5) is detected when misfirings of cylinders (110) assigned to an output stage bank of the injection device (5) are observed, and the fuel pressure has dropped below a threshold value (SW). The responses to the faults that are implemented differ depending on the faults that were detected.

Abstract: The invention relates to a method and a device for operating an injection device (5) for an internal combustion engine, the injection device (5) including injection valves (40), via which fuel is injected directly into combustion chambers (100) of the internal combustion engine. Means are provided for detecting misfirings (310), and for determining a fuel pressure (320). A mechanical fault of an injection valve (40) is detected when a misfire occurs in a cylinder (110) and the fuel pressure simultaneously drops below a threshold value (SW). An electrical fault in an injection device (5) is detected when misfirings of cylinders (110) assigned to an output stage bank of the injection device (5) are observed, and the fuel pressure has dropped below a threshold value (SW). The responses to the faults that are implemented differ depending on the faults that were detected.

Abstract: A method of heating a main catalytic converter positioned downstream from at least one primary catalytic converter by supplying unburned fuel generated by the engine in the exhaust gas upstream from the main catalytic converter while at the same time surplus air is present upstream from the main catalytic converter, where the generation of unburned fuel by the engine takes place at a separate time and/or place from the generation of surplus air in the exhaust gas by the engine.

Abstract: The invention is directed to a method and a control apparatus for operating an internal combustion engine especially of a motor vehicle. The engine has a combustion chamber (3) into which fuel is directly injected and is combusted in a homogeneous mode of operation or in a stratified-charge mode of operation. The engine includes an underpressure store (6) connected to an intake manifold (1). The underpressure store (6) makes available the auxiliary energy which is required for the servo units (8, 10, 11) of the motor vehicle. In the method and control apparatus, a throttle (19), which is provided in the intake manifold (1), is so adjusted during stratified-charge operation of the engine that the pressure in the intake manifold (1) is reduced in the event that a suppressed injection is present especially because of overrun fuel cutoff or a charge of pressure to the underpressure source (6) because of at least one servo unit (8, 10, 11) whereby the underpressure in the underpressure store is reduced.