EGR is a widely adopted route to reduce NOx emissions is Exhaust Gas Re-circulation (EGR).
This involves recirculating a controllable proportion of the engine's exhaust back into the intake air.
A valve is usually used to control the flow of gas, and the valve may be closed completely if required.
How do EGR valves work?
- The EGR Valve creates a loop back from the exhaust manifold to the intake manifold to recirculate burnt gases.
- The EGR valve has a solenoid which controls the valve which in turn is controlled by the ECU.
- The ECU operates the solenoid by using a duty request cycle in order to open the valve and recirculate the burnt gases.
- The Manifold Absolute Pressure sensor is then used to record the amount of additional gas which subsequently feeds back to the ECU as a control measure.
EGR valve problems
As the EGR valve is constantly working with burnt exhaust gases they naturally have high soot content.
This soot in the gases causes a build-up of carbon deposits around the valve which inhibits its operation and can cause it to get stuck in certain positions as the valve is orginally designed to pulse.
For full engine performance the EGR valve is closed which creates a closed circuit for the turbo system to operate correctly with the waste gas flowing down the exhaust.
A problematic EGR can create an open loop environment for the turbo exhaust pressure as it provides route back to the intake manifold and as a result can cause boost issues along with huge reductions in power and also fuel economy!
EGR removal benefits
Removing/Deleting the EGR Valve will result in the following;
- More Power
- Better Fuel Efficiency
- Less Flat Spots
- Improved Throttle Response
- Less Maintenance Costs
- Cleaner Intake System
- No Effect on MOT (NOx is not tested during a diesel MOT test)
EGR valve removal
There are two aspects to EGR Removal:
1. The EGR Valve is blanked preventing any exhaust gasses from passing through the valve and entering the intake system. EGR blanking is only required when the valves cannot fully close due to carbon build up.
2. The ECU is Remapped (Reprogrammed) and the EGR functions are removed from the ECU software or the valve is electronically programmed to remain closed at all times. This is the most important aspect of the job and it is vital that it’s done correctly. We can also remap the vehicle for better performance and fuel efficiency at the same time.