Catalytic Converter: Description and Operation

Catalytic Converter Heating Timing







In order to heat up the catalytic converter as fast as possible after start, the ignition will be retarded.

Retarded ignition in combination with an increase in idling speed will increase the temperature of the exhaust gases, which in turn heats the catalytic converter much faster. The function is active during start when the coolant temperature is between -10°C and 64°C. There will be no ignition retardation outside this temperature range.

The Control module contains an ignition timing matrix that is added to the idle speed ignition timing or the normal ignition timing when catalytic converter heating is active.

The function is active for up to 5000 ignitions at low coolant temperatures and drops as the temperature rises, down to 1000 ignitions at 64°C.

The ignition retardation is dependent on load and engine speed with a typical ignition timing of around 10° ATDC.