EGR System - Gasoline: Description

The exhaust gas recirculation (EGR) system is used to reduce the formation of NOx emissions by reducing combustion temperature. This is accomplished by recycling metered amounts of exhaust gas back into the intake system.

Each system has a vacuum-operated EGR valve and a vacuum modulator. All models use temperature sensing devices for controlling EGR operation.

The device used could be a vacuum switching valve (VSV), a bi-metallic vacuum switching valve (BVSV), a thermostatic vacuum switching valve (TVSV), or a combination of these valves. A check valve, EGR cooler and computer can also be used on some models.