Abstract: In a method and system, the condition of a valve drive, particularly of valve clearance, and the position of at least one valve opening cam of a cam shaft of an internal combustion engine are recorded from processing signals which are generated by at least one impact sound sensor such as an electronic spark sensor. Preferably, at least one characteristic signal sequence is identified from signals generated by the impact sound sensor. The sequence occurs at a particular time during a cycle of the internal combustion engine, and is compared to a stored reference signal. As a result, the condition of a valve drive, e.g. the valve clearance, and/or the position of at least one valve opening cam of the cam shaft can be deduced.

Abstract: In a method and system, the condition of a valve drive, particularly of valve clearance, and the position of at least one valve opening cam of a cam shaft of an internal combustion engine are recorded from processing signals which are generated by at least one impact sound sensor such as an electronic spark sensor. Preferably, at least one characteristic signal sequence is identified from signals generated by the impact sound sensor. The sequence occurs at a particular time during a cycle of the internal combustion engine, and is compared to a stored reference signal. As a result, the condition of a valve drive, e.g. the valve clearance, and/or the position of at least one valve opening cam of the cam shaft can be deduced.

Abstract: The invention relates to a method for controlling the emission of fuel vapor from a fuel tank venting system in a preferably cylinder-specific intake duct of an internal, combustion engine, a control valve permitting the fuel vapor to reach the assigned intake duct synchronously with the intake cycle of the cylinder of the internal combustion engine, the opening time of the control valve being variable. Preferably, for controlling or metering larger amounts of fuel vapor, the opening time is placed in a range, in which there is a higher vacuum in the intake duct. On the other hand, for controlling or metering lesser amounts of fuel vapor, the opening time is placed in a range, in which there already is a lesser vacuum in the intake duct. The closing point of the control valve is also variable and this control valve is not opened, if there is excess pressure in the intake duct.