WS7 Exhaust Gas Analysis (petrol)

The exhaust gas analysis measures 6 different reading which consist of, Co, Lambda, HC, Co2, o2 and No. Pretty much all cars now have emission reducing devices such as cat converters and egr valves.  The downfall with a catalytic converter is that it needs to be hot to work properly, during its warm up time it is doing nothing to prevent bad emissions.

The first reading to take was at cold start.

As you can see, the engine temp is still cold, so the exhaust gasses are not hot enough to have warmed the cat up, you can tell this by the high readings.

The next readings we had to take was the engine starting to warm up.

As you can see the catalytic converter is still not hot enough to to start reducing emissions. The oxygen sensor has not had enough time to go into closed loop so it is still producing high hydrocarbons and Nox.

The next reading was with the engine at operating temperature

The engine is at operating temperature now, so both the oxygen sensor and catalytic converter are working. You can see the hydrocarbons have dropped by a fair bit since first start up, this shows that there is less petrol being injected. Also shown is the low O2 reading, this shows that most of the oxygen is being burnt , this is a good reading as it is under 2%.Lambda   is almost at 1 so it is nearly at stocihiometric.

Next we had to disconnect the spark plug and take a reading