Secondary air injection function - GF14.30-P-3012A
ENGINE 112.943,113.961 in MODEL 129 with CODE (494a) USA version
ENGINE 112.943,113.961 as of 1.6.00 in MODEL 129
ENGINE 112.910, 920 in MODEL 202 with CODE (494a) USA version
ENGINE 112.940,113.943 in MODEL 208 with CODE (494a) USA version
ENGINE 112.940, 113.843 as of 1.6.00 in MODEL 208
ENGINE 112.911/921 /941,113.940 in MODEL 210 with CODE (494a) USA version
ENGINE 112.911 /921 /941, 113.940 as of 1.6.00 in MODEL 210
ENGINE 113.960 in MODEL 215 with CODE (494a) USA version
ENGINE 113.960 as of 1.6.00 in MODEL 215
ENGINE 137.970 in MODEL 215, 220
ENGINE 112.944/113.941 /960 in MODEL 220 with CODE (494a) USA version
ENGINE 112.922 /944, 113.941 /960 as of 1.6.00, 112.975,113.948/966 in MODEL 220
ENGINE 112.942 /970, 113.942 /965 in MODEL 163
ENGINE 112.947 in MODEL 170
ENGINE 112.912 /916 /946 /953 in MODEL 203
ENGINE 112.912 /955, 113.968 in MODEL 209
ENGINE 112.913 /917 /949 /954, 113.967 /969 in MODEL 211
ENGINE 112.973, 113.963 in MODEL 230
The secondary air injection heats up the catalytic converter more rapidly to its operating temperature and thus improves the emission levels in the warming-up phase.
Function
The electric air pump (M33) is actuated through the secondary air injection relay. The current consumption of the electric air pump (M33) is as much as 35 A.
Air injection relay and air pump switchover valve (Y32) are actuated by is as much as 35 A.
Air injection relay and air pump switchover valve (Y32) are actuated by the motor electronics control unit simultaneously for maximum 90 seconds after engine start, if:
- Coolant temperature < 10 °C and < 60 °C
- Engine speed < 3000 rpm
- Throttle valve not fully opened.
After an actuation, the air injection remains blocked until the coolant temperature has risen to more than approx. +60 °C and then drops again to below 40 °C.
The pump draws in air through a maintenance-free filter and pumps it to the air shutoff valve. The valve at the same time prevents exhaust gases from flowing back to the air pump (check valve for injected air discontinued).
The air pump switchover valve is supplied with vacuum from the intake manifold through a check valve. The air pump switchover valve, when actuated, switches the intake manifold pressure through to the air shutoff valve (126). The aspiration shutoff valves open and the air supplied by the air pump is forced through drillings in the cylinder heads to the exhaust side.
The injected air reacts with the hot exhaust gases in the outlet port. An oxidation of carbon monoxides (CO) and hydrocarbon (HC) takes place and results in an additional increase in the exhaust temperature.
On engine 137 the secondary air injection can be actuated individually for each bank of cylinders because of the cylinder shutoff, two air pump switchover valves (Y32/1, Y32/2).
| ME-SFI control unit position/task/design/ function | GF07.61-P-5000F | ||
| Air pump, location/task/design/function | GF14.30-P-3100F | ||
| Crankshaft position sensor, location/task/ design/function | GF07.04-P-4116F | ||
| Coolant temperature sensor, location/task/ design/function | GF07.04-P-5026A | ||
| Air shutoff valve, location/task/function | GF14.30-P-4028F | ||
| EA/CC/ISC actuator, location/task/design/ function | GF30.22-P-4010F | ||
| Lambda control function | GF07.61-P-4022F | ||
| Air pump switchover valve, location/task/ design/function | GF14.30-P-3103A | ||
| Secondary air injection relay, location/task/ design/function | GF14.30-P-3101F | ||
| Three-way catalytic converter location/task/ design/function | GF49.10-P-3002F |