Exhaust Gas Recirculation System

The Exhaust Gas Recirculation (EGR) system is designed to reduce the amount of Oxides of Nitrogen (NOx) created by the engine during operating periods that usually result in high combustion temperatures. NOx is formed in high concentrations whenever combustion temperatures exceed about 2500'F.

The EGR system reduces NOx production by recirculating small amounts of exhaust gases into the intake manifold where it mixes with the incoming air/fuel charge. By diluting the air/fuel mixture under these conditions, peak combustion temperatures and pressures are reduced, resulting in an overall reduction of NOx output. Generally speaking, EGR flow should match the following operating conditions:

• High EGR flow is necessary during cruising and mid-range acceleration, when combustion temperatures are typically very high

• Low EGR flow is needed during low speed and light load conditions

• No EGR flow should occur during conditions when EGR operation could adversely affect engine operating efficiency or vehicle driveability (engine warm up, idle, wide open throttle, etc.)

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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