Exhaust Gas Recirculation (EGR) Function And How It Works
The Exhaust Gas Recirculation (EGR) system has long been introduced to car engines. In line with the automotive industry's need to create vehicles with more environmentally friendly exhaust emissions, the EGR system is now widely applied to every car engine, whether cars with gasoline engines or cars with diesel engines.
As the name implies, Exhaust Gas Recirculation (EGR) is a system that regulates part of the exhaust gas that comes out from the exhaust manifold to be recirculated into the intake manifold. So, some of the exhaust gas leftover from combustion in the engine will be fed back through the intake manifold to be reused as control over the exhaust gas's emission content.
So what is the function of this EGR? And why must some of the exhaust gas recirculate into the intake manifold? This article will share some information about the Exhaust Gas Recirculation (EGR) function and how it works in cars. Check out the info below ...
I. What does exhaust gas recirculation (EGR) do?
The EGR function in a car engine is to reduce the formation of NOx gas in the exhaust gas from the engine combustion by circulating a small amount of exhaust gas to return to the combustion chamber through the intake manifold.
The amount of exhaust gas that is recirculated back into the intake manifold really depends on the type of engine used, whether a gasoline engine or a diesel engine. However, it is not more than 20% because this residual exhaust gas can impact the engine power generated inside the combustion chamber.
NOx gas is a poisonous gas that can interfere with the human respiratory system and trigger acid rain. NOx gas is the combustion product between NO (Nitrogen) and O2 (Oxygen) at high temperatures in the engine combustion chamber.
Therefore, it is necessary to have a system on the engine that can reduce the NOx gas content created from the engine combustion, namely the Exhaust Gas Recirculation (EGR) system. With the EGR system installed in this car engine, the NOx content that comes out with the combustion's exhaust gases can be minimized. The remaining exhaust gases that come out of the car exhaust can be more environmentally friendly.
II. How does exhaust gas recirculation (EGR) works?
In general, the exhaust gas that comes out from the combustion chamber will flow through the exhaust manifold to be continued until it comes out of the car exhaust pipe. Some of the exhaust gas that flows in the exhaust manifold is partly recirculated through a channel installed between the exhaust and intake manifold.
To prevent problems with the car engine due to the return of exhaust gas entering through the intake manifold, such as unstable idling, a decrease in engine power, and knocking. Thus, the exhaust gas flowing in the EGR channel must be controlled and regulated by using a valve known as the EGR Valve.
The Engine Control Unit directly controls the EGR Valve. Meanwhile, to adjust the EGR valve's motion, there is an EGR system that uses a solenoid with a vacuum air system, and there is also an EGR that works by using an electric motor system that works electrically.
When the engine is idling, the EGR Valve will normally close so that no exhaust gas flows into the intake manifold.
When the engine working temperature has started to heat up and the engine workload has increased, the EGR Valve will open based on an ECU order. Simultaneously, the volume of exhaust gas flow can be adjusted to the engine's needs.
The entry of a controlled amount of exhaust gas into the intake manifold is calculated to lower the temperature in the combustion chamber to reduce the formation of NOx gas. That way, the NOx levels in the exhaust gas are reduced so that the vehicle exhaust gases become more environmentally friendly.