GF14.20-P-3000P Exhaust Gas Recirculation, Function

GF14.20-P-3000P Exhaust Gas Recirculation, Function
ENGINE 642 in MODEL 203.0, 164.1 /8, 221.1 /0, 251.0, 203.2, 251.1 up to Model Year 2008 /YoM 07
ENGINE 642 in MODEL 211.2 /6, 209.3 /4, 211.0, 219.3
ENGINE 642 in MODEL 461.3
ENGINE 642.9 in MODEL 463.3 up to 31.5.12

Exhaust gas recirculation (EGR) is active at low load and speed ranges. The EGR rate depends on engine load and engine speed.
To do this, the CDI control unit (N3/9) reads in information from the following components:
^ Left hot film mass air flow sensor (B2/6) (except model 461)
^ Right hot film mass air flow sensor (B2/7) (except model 461)
^ hot film mass air flow sensor (B2/5) (model 461)
^ Charge pressure sensor (B5/1)
^ Charge air temperature sensor (B17/8)
^ CAT temperature sensor (B19)
^ Pressure sensor downstream of air filter (B28/5) (except model 463)
^ Pressure sensor downstream of air filter, right cylinder bank (B28/5) (Model 463)
^ Accelerator pedal sensor (B37)
^ Crankshaft Hall sensor (B70)

After evaluating the input signals, the CDI control unit uses the stored performance map to actuate the left exhaust gas recirculation positioner (Y27/9) (except model 461) or the exhaust gas recirculation positioner (Y27/9) (model 461) with a pulse width modulation (PWM) signal. The orifice area is enlarged, downsized or closed completely by the exhaust gas recirculation positioner, depending on actuation by the CDI control unit. More, less or no exhaust at all is fed back into the charge air manifold depending on the valve position.

Via EGR, the NOX levels in the emissions are reduced. It does this in 3 ways:
^ The oxygen (O2) concentration is reduced in the combustion chamber
^ Reducing exhaust flow
^ Reduction of the combustion temperature by the higher heat collection propensity of the components (e.g. water (H2O) and carbon dioxide (CO2)), which are not involved in combustion, but influence the process

To increase effectiveness of the EGR, the exhaust gas is passed through the exhaust gas recirculation cooler.

The left exhaust gas recirculation positioner is integrated in the cooling circuit of the engine in the following models as protection against thermal loads:
^ Model 211.022 with OM 642.920 with code (494) USA version
^ Model 211.022/222 with OM 642.920 with code (498) Japan version
^ Model 211.024 with OM 642.920
^ Model 164.1/8 with OM 642.940 with code (494) USA version
^ Model 251.0/1 with OM 642.950 with code (494) USA version