Abstract: In a method for detecting leaks in a motor vehicle tank ventilation system which includes an adsorption filter connected to the tank, via a ventilation conduit, to the induction pipe of an internal combustion engine via a discharge conduit and to the atmosphere via an air supply conduit, a shut-off valve arranged in the air supply conduit is closed to isolate the system from the atmosphere, a regeneration valve arranged in the discharge conduit is then opened so as to generate in the system a predetermined vacuum up to a point of time at which a stable equilibrium state of the air/fuel ratio in the system is achieved, the regeneration valve is then closed to isolate the system also from the induction pipe, and the vacuum in the system is subsequently maintained over a predetermined period and the existence of a leak in the tank ventilation system is indicated if the vacuum in the system falls below a predetermined threshold value during the predetermined monitoring period.

Abstract: An internal combustion engine has a catalytic converter in its exhaust gas path. In the catalytic converter, two exhaust gas emission measuring probes are provided spatially separated from one another. The phase shift between the output signals of these two measuring probes is used as a measure of the aging of the catalytic converter.

Abstract: A self-optimizing control method for optimizing the fuel/air ratio under non-steady conditions in an internal combustion engine is described; in this method, a probe is provided both before and after the catalyst. Control quantities and the time during which the post catalyst probe shows an undesirable fuel/air ratio are stored for certain specified engine-operating conditions in the non-steady range. When the same engine operating condition is repeated, reference is made to the stored control quantities and time and the control quantity is varied in the direction of the correct fuel/air ratio. The time now obtained is compared with the stored time and, if the time has decreased, the new control quantity and the new time are stored. The control values are iteratively corrected by repeating these procedures, when the same engine operating condition reappears, until the time reaches a minimum.