DME Digital Engine Control: Description
The 911 Carrera, 924-S and 944 models are equipped with Bosch Digital Motor Electronic (DME) engine control system. The DME system uses various data sensors to monitor intake air volume, engine speed, crankshaft position, coolant temperature, intake air temperature, and throttle position. Signals from these sensors, as well as a start signal and oxygen sensor signal, are sent to the Control Unit (CU).
The CU is a microcomputer. Using information obtained from data sensors, the CU determines the correct amount of fuel and optimum ignition timing.
The 924-S and 944 DME control unit switches from open loop to closed loop operation when coolant temperature is above 113°F (45°C), and when oxygen sensor temperature is above 480°F (250°C).