Nissens EGR System Parts

FUNDAMENTALS

EGR coolers are part of advanced EGR systems integrated with an electrically operated EGR valve. The application of the cooler improves the engine's overall emissions performance as it cools the exhaust gas further down before it's directed into the combustion chamber. The primary objective of the EGR system is to reduce the peak combustion temperature, which hinders the formation of NOx gases. 

Hence, lowering the exhaust gas temperature improves this effect.

The size and shape of the EGR cooler depend on the engine size, type, and emissions standard.

OPERATION

• The EGR cooling depends on heat exchange between the engine coolant that flows through the cooler's EGR gases circuit. Flows of the two mediums are separated, and the engine coolant dissipates the heat of the exhaust gases.
   
• A bypass flap integrated with the cooler enables flow control of the exhaust gases throughout the cooler, depending on the momentary engine needs. The flap can be actuated pneumatically or electronically.
   
• Bypassing the EGR gases from the cooler helps the engine and its equipment (e.g., catalytic converter) achieve the operational temperature faster, especially by a cold start. It also reduces the combustion noise of a cold engine and its emissions of hydrocarbons in the warming-up mode.

EGR COOLING ADVANTAGES

• Increases volumetric capacity of the EGR gases
• Lowers temperature of the combustion
• Contributes to the overall increase of the EGR effect and, thus further improves the NOx reduction