A method and a device for controlling an internal combustion engine, and in particular a diesel engine during the start-up operation, are described in U.S. Pat. No. 4,516,550, which corresponds to German Unexamined Patent Application No. 32 09 433. In the method described therein, the fuel quantity is specified dependent upon an r.p.m. value and upon a time condition.
Associated with this method and this device is the disadvantage that a defect in the speed sensor leads to unacceptable operating conditions. If the speed sensor fails, the speed signal does not attain the designated limiting value. The result is a continuous increase in the fuel quantity to be injected. This leads to unacceptable operating conditions for the internal combustion engine.
U.S. Pat. No. 4,402,290, which corresponds to German Unexamined Patent Application No. 29 45 484, describes an interrupting device, which usually enables the internal combustion engine to be turned off when unacceptable operating conditions occur. In one specific embodiment, the starting quantity is released only when the r.p.m. value has exceeded a specified value. The disadvantage of this procedure is that the starter is first actuated and then the starting quantity is released. This can result in the controlling (positioning) mechanism not reaching the position required for the starting quantity, particularly when there is a drop in the supply voltage. It is thus feasible that no start-up operation is possible when a battery is not completely intact, particularly at low temperatures.