Operation

OPERATION
The EZL/AKR control unit receives information concerning:

^ Voltage supply (+)
^ Engine speed from crankshaft position sensor (L5)
^ Cylinder #1 position from camshaft position sensor (L5/1)
^ Engine load condition from intake manifold vacuum signal
^ Selection of ignition map from EZK/AKR reference resistor (R16/2)
^ Shift preconditions from transmission overload protection switch (S65)
^ Combustion knock from knock sensors (A16)
^ Fuel injection information from LH control unit (N3/1)
^ Throttle position from Electronic accelerator control unit (N4/1)
^ ABS/ASR information from ABS/ASR control unit (N30/1)

The EZL/AKR control unit compares information from these inputs with ignition maps for typical load and speed ranges which are stored in the microcomputer. The optimal ignition timing for each operating condition is instantaneously determined from the stored maps and the power output stage switches the primary current of the ignition coils.

Furthermore, a TD (engine speed) reference signal is provided to the LH control unit, tachometer, on-board diagnostic connector, and the diagnostic socket. To further increase operating reliability, a data exchange circuit has been added between the EZL/AKR control unit and the LH control unit. Information concerning the coolant temperature, intake air temperature and the intake manifold absolute pressure is continuously compared by the control unit of each system.

During cranking and up to approx. 450 RPM, the ignition timing is controlled via the segment edges (fixed) of the flywheel. After approx. 460 RPM has been attained a transition from the fixed ignition timing to dynamic ignition timing (instantaneous, ignition map comparison) is made. Various ignition characteristic curves are inhibited in the warm-up range depending on the coolant temperature in order to reach the normal operating temperature as rapidly as possible.

When a full load signal is received from the electronic accelerator control unit (N4/1), the EZL/AKR control unit adapts a fixed full load ignition map characteristic. At temperatures above approx. 203°F the ignition will be retarded to counter any further rise in temperature.