First bankers, now cars makers Options

[Andy Capp]

In this alleged free market economy, people should be going to gaol.

http://www.bbc.co.uk/news/business-34322016

[CrackerJack]

The game here is about NOx which is one of the main toxic components of exhaust fumes. Diesels produce more NOx than petrol due to the higher combustion pressures.

When you hook up a vehicle to the test rig it (the test rig) monitors various parameters via the engine management system and sensors. VW, GM, and several others [probably all] have written a routine into the software that detects when the test kit is hooked up and operates the engine in such a way that NOx emissions are reduced.

NOx is formed by heat and pressure and since turbo diesels a) run hot and generate lots of pressure in the cylinders, they generate more NOx than petrol engines.

Basically reducing NOx increases particulates and vice versa. So, when on test you run the engine in a mode the reduces NOx but will eventually clog up the DPF and Cat. Since the test is short, you can afford to this and then revert to normal operation once the test has finished.