EGR SYSTEM FUNCTION[ZJ, ZY, Z6]

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With Throttle Valve Actuator Only

• The high occurrence of the nitrogen oxide (NOx) at high temperatures has been reduced by recirculating exhaust gas to the combustion chamber in order to lower the combustion temperature.

• The maximum supplied amount of the EGR gas has been increased with the adoption of the high-capacity EGR valve, reducing pumping loss which is one of the causes for engine output loss.

• With the adoption of the EGR cooler, exhaust gas temperature is decreased that flows through the EGR valve and the following effects have been obtained.

― Epithermal effect to the EGR has been reduced by decreasing the exhaust gas temperature.

― By decreasing the exhaust temperature of the fed EGR gas, the combustion temperature is suppressed and NOx is reduced.

― By decreasing the exhaust temperature of the fed EGR gas, the volumetric efficiency (charging efficiency) has been improved.

In addition, because the knocking limitation can be increased by suppressing the combustion temperature, the ignition timing has been maximally advanced and the combustion efficiency has been improved.