Abstract: The invention is directed to a multi-engine drive system with at least two engines which have a common crankshaft. In order to test if both engines are operating properly, a mutually oppositely directed modulation of the throttle flap angles of the throttle flaps is caused by a control unit to occur periodically in the context of a test function. If this test function causes a change in the rotational speed of the crankshaft, then this means that the two engines are no longer operating symmetrically so that a disturbance is present. In this way, a continuous monitoring of the operation of both engines is provided.

Abstract: A safety device is proposed for an internal combustion engine which is operated with supercharging in combination with both a fuel metering system and a control unit for the instant of ignition. The safety device is characterized in that it controls the fuel metering in accordane with the volumetric efficiency of the engine. In the case of an excessively high volumetric efficiency, a defect of the charger or of the charge-pressure regulator is presumed. In order to protect the engine from mechanical and thermal overload, the fuel metering in this case is either reduced or shut off completely. The subsequent reinitiation of the fuel metering is suitably effected in combination with a late instant of ignition or a late injection onset in order to prevent a jump in torque.

Abstract: A regulating device is proposed for an internal combustion engine having a throttle device and a controllable bypass channel in the intake tube, where regulation is effected to a minimum volume (Q/n) in overrunning above a predetermined rpm value and to the idling rpm below this rpm value. The purpose of this regulating device is the substantially precise preliminary control of an adjustment member in the bypass channel around the throttle valve to the opening cross section required for idling. The regulating device includes a switchover device (alternating switch), to the input terminals of which the output signals of the regulators for volumetric value and for idling rpm are applied. In the case of temperature-dependent minimum and threshold volumetric values, good warmup performance can be attained.

Abstract: To permit operation of engines, particularly turbo-charged engines, at the maximum power level just short of causing engine knocking, and preventing engine knocking, temperatures in the engine are sensed and, if an excessive temperature signal is detected, for example excessive engine temperature, exhaust gas temperature, turbo-charged air, or turbo charger temperature, a fuel supply system, for example a fuel injection system, is controlled to enrich the mixture, for example by multiplying the fuel injection time by a factor as commanded by an additional control stage (26, 27, 30) which stores in a memory, such as a ROM (27), engine operating characteristic curves. In addition, spark retardation by a retarding angle (.alpha.