Audi Ag

Siegfried Meixner

Oliver Grunwald

Marcus Schiele

Mark Banzer

Peter Enders

Gerold Berthold

A drive device for a motor vehicle includes an exhaust pipe and a secondary air device having a first secondary air path which feeds into the exhaust gas pipe. Disposed in the first secondary air path is a secondary air pump and a secondary air valve. To compensate, for example, fluctuations in the supply voltage of the secondary air pump, provision is made for arrangement in the secondary air path of a Laval nozzle which can be placed downstream of the secondary air valve.

Drive device for a motor vehicle and method of operating such a drive device

The invention relates to a method for checking the function of a tank venting valve between the intake manifold of an internal combustion engine and a fuel tank or a fuel vapor reservoir in which the tank venting valve in operation of the internal combustion engine is opened several times and is closed again after a short opening time and in which during repeated opening and closing the time characteristic of a quantity which is dependent on the opening state of the tank venting valve is recorded. In order to enable a reliable function check of the tank venting valve even in the case of very small and/or time-shifted amplitudes of the quantity to be monitored, it is proposed, according to the invention, that the first derivative of the time characteristic of the quantity be evaluated.

Method for checking the function of a tank venting valve

The invention relates to a method for testing the mobility of the negative pressure relief valve of the fuel system of a motor vehicle, the negative pressure relief valve depending on the pressure within the fuel system having to be moved between a closed position which closes the fuel system and an open position which clears the fuel system, with the following steps: a) Testing the position of the negative pressure relief valve; and b) Testing the position of the negative pressure relief valve in reaction to a pressure increase within the fuel system if the negative pressure relief valve in step a) was in the closed position. The invention furthermore relates to a system for testing the mobility of the negative pressure relief valve of the fuel system of a motor vehicle.

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Hofstetten, Germany

Siegfried Meixner