My previous article teached you something about modern car emission control systems. In this article I will explain you through a series of pictures how these are implemented in the Opel/Vauxhall Vectra C 1.9 CDTI with Z19DTH engine code.
For starters let’s have a look at the front of the car with radiator, intercooler and airco heat exchanger removed:
The engine block itself can easily be noticed central in this picture. The air intake is at the left side in this picture next to the front light, from there on the air flows into the air filter and back out into the turbo which is the brownish rusty thing also at the center of the picture. The turbo uses the exhaust gas to spin up and so it is fixed onto the exhaust gas manifold. The exhaust gas manifolds collects all the exhaust gas that has been created inside the engine due to the burning of air and fuel. It collects it and brings it to together and then runs the exhaust gas to the turbo which will spin up at the exhaust side and at the air intake side (because both compressor wheels are physically connected). And so the intake air will get compressed which allow for more air inside the engine and so more fuel to burn which increases the engine performance in general. Another shot of the front of the engine:
The EGR (exhaust gas recirculation) system for the Z19DTH engine takes exhaust gas from the exhaust manifold. In the above picture you can clearly see the bigger hole on the right side where some of the exhaust gas will be collected. The picture before also has an indication where this hole is located. So, some of the exhaust gas will be used to drive the turbo, other remaining exhaust gas will be reused in the EGR system. From that particular hole that I just described, the exhaust gas flows through the EGR cooler and back into the air intake system. The EGR cooler is cooled be the same water that cools the engine, and looks as following:
From exhaust manifold to intake manifold:
In real life:
In the above picture, the thing next to the EGR cooler is the EGR valve. The black part of the valve is the electronics to drive it. Inside the iron housing there is more or less a small iron bar which will control the valve and make it possible for exhaust gas to either be mixed with the compressed intake air or not used at all. The EGR valve sits on the back of the engine where there is the intake manifold.
The intake manifold is where both EGR’ed exhaust gas and compressed intake air flow together. The intake manifold will guide the mixture inside the engine where it is used for burning fuel. Another view at the back of the engine:
In real life:
And so air travels inside the inside, helps burning the fuel and leaves the engine again through the exhaust manifold, to either be reused again for driving the turbo or for the EGR system. For today that’s enough details, more later!