Principle of operation
Exhaust gas recirculation (EGR)
The EGR system recycles exhaust gases back through the combustion process to reduce NOx emissions.
By introducing this gas into the air intake, oxygen content and combustion temperatures are reduced, which reduces the NOx emissions.
High EGR flow is necessary during cruising and mid-range acceleration, when combustion temperatures are typically very high, while lower EGR flow is needed during low speed and light load conditions.
No EGR flow should occur during conditions when it could adversely affect engine operating efficiency or vehicle driveability, such as engine warm-up, idle, etc.
The EGR function is managed by the engine control module (ECM), which controls the operation of a solenoid, allowing precise control of the vacuum to the EGR valve actuator.
The ECM determines the optimum EGR flow using inputs from sensors in the engine management system, including the mass air flow meter, cylinder head temperature sensor, intake air temperature sensor, and fuel metering valve.
Exhaust gas recirculation (EGR)
The EGR system recycles exhaust gases back through the combustion process to reduce NOx emissions.
By introducing this gas into the air intake, oxygen content and combustion temperatures are reduced, which reduces the NOx emissions.
High EGR flow is necessary during cruising and mid-range acceleration, when combustion temperatures are typically very high, while lower EGR flow is needed during low speed and light load conditions.
No EGR flow should occur during conditions when it could adversely affect engine operating efficiency or vehicle driveability, such as engine warm-up, idle, etc.
The EGR function is managed by the engine control module (ECM), which controls the operation of a solenoid, allowing precise control of the vacuum to the EGR valve actuator.
The ECM determines the optimum EGR flow using inputs from sensors in the engine management system, including the mass air flow meter, cylinder head temperature sensor, intake air temperature sensor, and fuel metering valve.
Stage 4 emissions
There are changes for this model year in terms of the addition of the EGR valve position sensor to help control system flow more accurately.