Air Injection: Description and Operation
GF14.30-P-3012V The Air Injection Function
ENGINE 272.920 in MODEL 203 up to Model Year 8
ENGINE 272.922 in MODEL 211
ENGINE 272.940 in MODEL 203 up to Model Year 8
ENGINE 272.941 in MODEL 203 up to Model Year 8
ENGINE 272.942 in MODEL 171 up to Model Year 8
ENGINE 272.943 in MODEL 211, 219
ENGINE 272.944 in MODEL 211
ENGINE 272.945 in MODEL 251 up to Model Year 8
ENGINE 272.946 in MODEL 221 up to Model Year 8
ENGINE 272.960 in MODEL 203 up to Model Year 8
ENGINE 272.963 in MODEL 171 up to Model Year 8
ENGINE 272.964 in MODEL 211, 219
ENGINE 272.965 in MODEL 221 up to Model Year 8
ENGINE 272.966 in MODEL 230 up to Model Year 8
ENGINE 272.967 in MODEL 164, 251 up to Model Year 8
ENGINE 272.970 in MODEL 203 up to Model Year 8
ENGINE 272.972 in MODEL 211
ENGINE 272.975 in MODEL 221 up to Model Year 8
ENGINE 273.922 in MODEL 221 up to Model Year 8
ENGINE 273.923 in MODEL 164 up to Model Year 8
ENGINE 273.924 in MODEL 221 up to Model Year 8
ENGINE 273.960 in MODEL 211, 219
ENGINE 273.961 in MODEL 216, 221 up to Model Year 8
ENGINE 273.962 in MODEL 211
ENGINE 273.963 in MODEL 164, 251 up to Model Year 8
ENGINE 273.965 in MODEL 230 up to Model Year 8
ENGINE 273.967 in MODEL 209
ENGINE 273.968 in MODEL 221 up to Model Year 8
ENGINE 272.940 in MODEL 209
ENGINE 272.960 in MODEL 209
Shown on engine 272.963 in model 171
126/1 Left shutoff valve air injection (combination valve: Check valve integrated)
126/2 Right shutoff valve air injection (combination valve: Check valve integrated)
128 Check valve (vacuum)
B11/4 Coolant temperature sensor
B70 Crankshaft Hall sensor
M33 Electric air pump
N3/10 ME-SFI [ME] control unit
N10/1kO Relay module, AIR pump
Y32 Air pump switchover valve
a Vacuum supply from intake manifold
b Air admission
c Injected air to the outlet ducts at the right cylinder head
d Injected air to the outlet ducts at the left cylinder head
The air injection more rapidly warms up the catalytic converters to operating temperature and thus improves the exhaust emission values in the warming-up phase.
The electric air pump is actuated over the air pump relay. The current consumption of the electric air pump is as much as 45 A.
The air pump relay and air pump switchover valve are actuated by the ME-SFI [ME] control unit simultaneously for a maximum of 40 seconds following engine start if the following conditions are fulfilled:
- Coolant temperature -10°C and < 35°C
- Coolant temperature (USA) +7°C and < 35°C
- Engine speed < 2500 rpm.
Following actuation, air injection remains locked if it has run sufficiently long enough to warm up the catalytic convertors (maximum 40 seconds). A new enable of the air injection will only take place if the catalytic convertors cool down again due to a sufficiently long stoppage of the engine. For the purpose of diagnosis, air injection can also be enabled for a short time when the engine is warm.
If the electric air pump is actuated over the air pump relay it suctions in injected air from the tight air filter housing and delivers it to the combination valves.
The switchover valve air pump is actuated parallel to the air pump.
In this way vacuum travels from the intake manifold to the aneroid capsules on the combination valves.
The combination valves open and the air delivered by the air pump is pushed through the holes to the outlet ports.
Check valve are integrated into the combination valves which prevent reverse currents of hot exhaust into the combination valves and air pump.
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.
The air injection can be willfully actuated using STAR DIAGNOSIS for a maximum of 2 minutes. Prior to the next actuation, it is essential to maintain a cooling time of 30 minutes, otherwise the air pump may be damaged.
