Exhaust Gas Recirculation (EGR)

What is an EGR and how does it work?

An EGR is a device that recirculates a portion of your exhaust gases back into the combustion processes. A portion of the gasses recirculates through a separated pipe that is attached to your exhaust system, from there it gets cooled off by a water cooled device that's part of the EGR unit, after the cooling process the exhaust gases are controlled through the EGR valve pumping it back into the intake process thus cooling the combustion process and reducing harmful emissions.

What are the benefits of an EGR?

When the EGR recirculates a portion of your exhaust gases it reduces harmful emissions, Nitrous oxide is one of the harmful gases that's created when your combustion process temperature rises above 1300 +/- degrees Celsius. The EGR reduces the amount of (NOx) gases released into the atmosphere by re burning the induction of exhaust gas.

NB: NO2 is a harmful air pollutant and reacts in the atmosphere damaging the ozone (O3) and can cause acid rain.

Common Problems associated with EGR

Even though the EGR provides vast environmental and air quality benefits, but they are not without their problems.

People who experience the most problems with an EGR are diesel car owners

• EGR reduce the available oxygen and fuel mixture in the cylinder this in turn Increases the production of particulates(fuel which has only partially combusted)
• EGR can malfunction due to carbon and soot build up inside the valve mechanism
• Hard starting or rough idle this happens if your EGR fails to close, causes your exhaust gasses to leak into your intake
• Replacing the unit can be a costly procedure

How will I know if my EGR valve is malfunctioning?

As with most modern cars, when the ECU detects an issue it will display a relevant warning light, and the engine will most likely be idling rough.

The easiest way to detect the cause of your troubles is to go for a diagnostics analysis.

How does an EGR influence a vehicles performance?

A whole industry has been built up around the removal and blocking of problematic EGR valves, or by disabling the functionality of the EGR

NB: The complete removal of the EGR system is still a contested subject.

The EGR is controlled by your vehicles computer box (ECU), say now you want that extra couple of horses for the traffic light GP, your ECU will detect that the throttle of your vehicle is wide open thus closing the EGR valve allowing your vehicle to have a clean air mixture giving you the extra performance you need.

When normal driving conditions are met the ECU will communicate with the EGR allowing the EGR valve to open for the gases to start its recirculation process and thus decreasing your combustion temperature and harmful gases created by the motor.

But if your EGR malfunctions it may well reduce your power and increase fuel consumption.

Why block an EGR?

The EGR is like a little gremlin, it is nice to have knowing it helps the environment but when disaster strikes it is bad, a new EGR unit is an expensive component to buy and a very labour intensive job to replace, so what can we do about it?

The most simple and advanced way to do it is using software to reprogram the ECU. So what that means is that when they reprogram the ECU, they shut down the EGR valve and stop it from opening so that the recirculation stops.

How does that benefit you?

• You will always have continuous power from normal driving to max performance you will always have the 100% power backing you up.
• Your vehicle will be lighter on fuel because you will have a complete combustion
• You will have no soot and carbon building up in your intake manifold
• You never have to replace your EGR, there will not be a costly fee

Should you wish to discuss any particular technical issues about your exhaust system we at Powerflow Durban North would gladly oblige. Pay us a visit with your car to enable us to inspect and advise.