Injection Control

OPERATION
Injection Control
The Digital Motor Electronic (DME) control unit calculates the correct injection time on the basis of the engine speed, air flow, throttle position, oxygen sensor voltage. engine temperature and intake air temperature. The mixture is varied by the opening time of the injector valves. The battery or system voltage is also taken into consideration in calculating the injection timing since the pull-up and drop-out times of the injector valves are extended as the voltage decreases.

Semi-Sequential Injection
There is injection in one group of cylinders (2 + 4 or 1 + 3) only once every 720 crankshaft degrees as from an engine speed of 600 rpm. This timing can function only when the DME control unit receives a signal from the camshaft sender (on camshaft sprocket of exhaust valves). Timing remains in semi-sequential injection if the signal is received later.

Parallel injection
Parallel injection means simultaneous activation of all fuel injectors for each crankshaft revolution and takes place only when the camshaft sender has not put out any signals since starting the engine. If a signal is put out later, the system switches over to semi-sequential injection as soon as an engine speed of 2500 rpm is exceeded.