ME-SFI catalytic converter heating-up, function - GF07.61-P-3032AMG

ENGINE 156.980 in MODEL 164, 251 up to Model Year 8 

ENGINE 156.982 in MODEL 209 

ENGINE 156.983 in MODEL 211, 219 

ENGINE 156.984 in MODEL 216, 221 up to Model Year 8 

Heating-up of the TWC is designed to heat up the catalytic converters more rapidly to its operating temperature (about 450°C) and thus to sharply reduce exhaust gas emissions for a cold start.

The ME-SFI [ME] control unit 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 O ₂ sensors.

The following conditions determine whether TWC heating is enabled:

• Engine starting temperature
• Altitude (atmospheric pressure)
• Residual heat in catalytic converters (from the model calculation)
• Difference between intake air and engine starting temperatures
• Air mass

The following systems are involved:

• Ignition system→ In the idle speed range and in line with the coolant temperature the ignition angle is retarded for e.g. 20 seconds in order to increase the exhaust gas temperature.
• Idle speed control →Dependent on coolant temperature, the idle speed is increased to approx. 1100 to 1300 rpm for up to 20 seconds.
• Camshaft adjustment → Special positions are specified separately for intake and exhaust camshafts for TWC heating.
• Air injection → The enriched mixture after start and in the warming-up phase contains more unburnt hydrocarbons in the exhaust. The injected air (afterburning) causes post-oxidation in the catalytic converters.

	Component description for adjustable camshaft timing solenoid	Y49/4, Y49/5, Y49/6, Y49/7	GF05.20-P-2100AMG
Component description for O 2 sensors	G3/3, G3/4	O2 sensors upstream of the TWC	GF07.04-P-6100AMG
	G3/5, G3/6	O2 sensors downstream of the TWC	GF07.04-P-6100AMH
Component description for fuel injection valves	Y62y1-Y62y8	GF07.03-P-6010AMG
Component description for coolant temperature sensor	B11/4	GF07.04-P-6040AMG
Component description for the pressure sensor	B28	GF07.04-P-6060AMG
Component description for the intake air temperature sensor	B17	GF07.04-P-6070AMG
Component description for the crankshaft Hall sensor	B70	GF07.04-P-6220AMG
Component description for hot film mass air flow sensor	B2/6, B2/7	GF07.07-P-6000AMG
Component description for ME-SFI [ME] control unit	N3/10	GF07.61-P-6000AMG
Component description for the electric air pump	M33	GF14.30-P-2000AMG
Component description of the air pump switchover valve	Y32	GF14.30-P-2020AMG
Component description for ignition coils	T1/1-T1/8	GF15.10-P-2100AMG
Component description for the throttle valve actuator	M16/3, M16/4	GF30.20-P-2020AMG
Component description for three-way catalytic converter	157, 158	GF49.10-P-2010AMG