An Exhaust Gas Recirculation (EGR) valve is used in which of the following?

Explanation:

Exhaust Gas Recirculation (EGR) Valve:

• The purpose of the exhaust gas recirculation (EGR) system’s purpose is to reduce NOx emissions that contribute to air pollution.
• An Exhaust Gas Recirculation (EGR) valve is used in the turbocharger.
• Exhaust gas recirculation reduces the formation of NOx and engine knock control.
• By re-circulating and allowing a small amount of exhaust gas into the intake air-fuel mixture on the intake manifold.
• EGR valve is connected between the exhaust port, or manifold, and the intake system.
• If engine conditions are likely to produce oxides of nitrogen, the EGR valve opens, letting some gases (only about 6 to 10% of the total) pass from the exhaust, into the intake system.
• During combustion, these exhaust gases absorb heat from the burning air and fuel.
• This lowers peak combustion temperatures (below 1500 degrees c) to reduce the reaction between nitrogen and oxygen that forms NOx.
• Older EGR systems use a vacuum-regulated EGR valve while newer vehicles tend to have an electronic EGR valve to control exhaust gas re-circulation.
• When the engine is idling, the EGR valve is closed and there is no EGR flow into the manifold.
• The EGR valve remains closed until the engine is warm and is operating under load.
• As the load increase and combustion temperatures start to rise, the EGR valve opens and starts to leak exhaust back into the intake manifold.
• This has a quenching effect that lowers combustion temperatures and reduces the formation of NOx.

Additional InformationTurbocharger:

• Turbocharger is mounted on the engine.
• It increases the amount of air delivered to the engine cylinder, thereby more fuel can be burnt which increases engine power.
• Whenever the density of air is less than the density at atmospheric pressure, especially at higher altitudes, the turbocharger helps the engine to get sufficient air.
• An engine may have one or more turbochargers.