GF07.61-P-3032M ME-SFI Catalytic Converter Heating-Up, Function

GF07.61-P-3032M ME-SFI Catalytic Converter Heating-up, Function

Component Identification:

The TWC heating-up function heats up the catalytic converters more rapidly to their operating temperature (300 to 450 °C) and thus considerably reduces the exhaust emissions in the cold start and heating-up phase.
The ME-SFI [ME] control unit (N3/10) is able to detect that the operating temperature has been reached and that the catalytic converters are operating at normal efficiency from the signals supplied by O2 sensors.

The following systems are involved in the TWC heating-up:
^ Ignition system:
At idle speed and coolant temperature dependent, the ignition angle is retarded for 20 seconds for example and thus the exhaust temperature is increased.

^ Idle speed control:
Dependent on coolant temperature, the idle speed is increased to approx. 1100 to 1300 rpm for a maximum of 20 seconds.

^ Transmission control:
The automatic transmission is upshifted later coolant temperature dependent. One starts off in 1st gear and the system is actively shifted down for TWC heating.

^ Secondary air injection:
After starting and during warm-up, the enriched mixture results in more unburned hydrocarbons in the exhaust. The injected air (high oxygen concentration) causes post-oxidation in the catalytic converters. Heat is released as a result, which more rapidly warms up the catalytic converters to operating temperature.