What does an EGR valve do on a diesel engine?

Abstract: Exhaust gas recirculation (EGR) is an effective strategy to control NOx emissions from diesel engines. The EGR reduces NOx through lowering the oxygen concentration in the combustion chamber, as well as through heat absorption.

Does oil go through EGR?

The is no oil going through the egr system, if there is oil in the coolant its most likely a failed oil cooler. If it has a failed oil cooler it would be very obvious just looking at the coolant expansion tank.

Can I drive with a faulty EGR valve?

Can I drive with a bad EGR valve? Technically, you can drive your vehicle with a bad EGR valve, but your vehicle will run rough, shake at idle, and a check engine light will be illuminated. You might also hear popping sounds while driving down the road.

Why a defect in the EGR system could cause excessive soot in engine oil?

The amount of exhaust gas introduced into the combustion chamber will displace oxygen, creating cooler combustion. Oils exposed to the EGR environment show an increase in soot content, acid number (AN) and viscosity, while the engine and oil are both exposed to corrosive/acidic gases and particle buildup.

Is EGR bad for diesel engines?

While “cooled” exhaust gas might not sound bad, diesel engines benefit tremendously from heat. When taking some of that in-cylinder heat away (i.e. utilizing EGR), NOx and hydrocarbon pollutants are reduced, but it comes at the expense of decreased engine performance and efficiency. Ultimately, EGR is here to stay.

Where does the oil come from in the EGR valve?

The oil is coming from your intake and from the recirculating exhaust gas flow. The EGR valve contains a piston that is raised and lowered by vacuum in response to commands from your ECU. The piston slides in a metal bushing.

Do you need EGR system for diesel engine?

Mack and Caterpillar have also developed tests for evaluating oil and engine performance in an EGR environment. Oil analysis has become more important than ever. These changes in diesel engine design, which include EGR systems, are pushing the performance requirements of diesel engine lubricating oil.

How does EGR affect the oxidation rate of oil?

Cooled EGR occurs when the engine coolant absorbs exhaust gas heat before entering the combustion chamber. Because the engine coolant takes up the heat from exhaust gases, the engine cooling system runs hotter, therefore the oil gets hotter. Oil oxidation rate doubles with every 18 degrees Fahrenheit.

How is EGR used to control NOx emissions?

New engine designs use EGR to control NOx emissions by recirculating exhaust gases back into the combustion chamber to be burned a second time, thereby reducing emissions associated with health risks. The amount of exhaust gas introduced into the combustion chamber will displace oxygen, creating cooler combustion.