Practically all modern engines are equipped with EGR. N43/N53 series engines are not exceptional.
As we know, the EGR valve allows returning part of the waste gases in the inlet manifold for repeated burning. You can find information regarding basic performance things of EGR on the Internet, so in this entry – about some nuances.
In the picture: EGR valve of the N53 series engine
- EGR calve reduces the number of harmful emissions in the exhaust gasses, but this is not the biggest benefit of using EGR;
- EGR saves fuel – replacing the air with a composition of non-burning gasses (waste gasses), it’s possible to increase the fulfillment of cylinders end reduce depression the inlet manifold. It allows reducing pumping losses – similarly as it’s done by the Valvetronic and Stratified charge. Stratified charge + EGR = even more economical car!
- allows to warm up CO catalytic converters more quickly – additional fuel savings;
- maintains correct temperature in the combustion chamber and in the exhaust, prolongs the life of the spark plugs and CO catalytic converters.
- EGR doesn’t reduce the torque (power) of the engine, because in case of large required torque the valve is closed – the impact of the EGR valve is 0;
- EGR doesn’t pollute the inlet if the engine is in working order. If CCV functions normally, even the engine with a mileage of 400’000 km or more can have both clean EGR and intake manifold.
Performance conditions of EGR:
- EGR is closed in idle of Homogeneous mode, to not impact the quality of idle (stability);
- the opening of EGR in idle of Stratified charge: around 10 .. 15% (for the warmed up engine);
- the opening of EGR in case of small/average load: 30% and more;
- the opening of EGR in case of large inquired torque – closed, to ensure max possible fulfilling of cylinders with the oxygen.
Management of EGR is ensured with DC motor (PIN 3 and 4). The position of the valve is constantly controlled by analogue sensor (potentiometer, PIN 1; 2; 5, signal: PIN 1; signal amplitude: 0 .. 5V).
The performance of EGR can be evaluated at: ../F5/Shift+F3
In this menu you can see:
- the voltage of the EGR valve sensor (0 .. 5 V) and appropriate calculated opening of valve in %;
- adaptation values in final points of the sensor (valve) and in range or small valve opening.
Correct adaptation values in the final points of the valve: 0.5 (+/-0.25) V and 4.5 (+/-0.30) V accordingly (2nd line of the menu).
- 0.5 (+/-0.25) V: EGR is closed;
- 4.5 (+/-0.30) V: EGR is fully open.
If these values are significantly different, possible defects:
- the valve is mechanically clogged and is not able to reach final positions due to this reason;
- the resistive layer of the sensor (potentiometer) has worn out – the sensor displays incorrect values.
As follows from connection and adaptation data – EGR controls both current position of the valve and measures the true impact of the valve on the gas (fuel) mixture.
Defects of EGR are not widespread, and my experience in work with N43/N53 series engines confirms, that the EGR valve is long-lasting and stable.
Test module of the EGR valve is found: F6/F2/F7
This test block (status: ignition ON; engine OFF) allows manually to change the required position of EGR, at the same time performing visual control of it.