General Information EGR
The exhaust gas recirculation system is a means to limit the emissions of oxides of nitrogen (NOx) by returning exhaust gases into the combustion chamber through the intake manifold. This process reduces the amount of oxygen present, lowers combustion temperature and restricts the formation of nitrous oxides.
As this system is required to be isolated during engine warm up and driving under specific load conditions, an electronic control unit is used to receive data from an engine speed sensor, a throttle position potentiometer and an engine coolant temperature switch. From this data, the control unit is able to determine the signals to be sent to the vacuum switching valves and hence the attitude of the two exhaust gas recirculation valves mounted on the intake manifold.