The Volkswagen AG emissions scandal that has led to the resignation of CEO Martin Winterkorn has sent shockwaves through the automotive industry. Volkswagen AG are going to end up being fined billions and billions of pounds for effectively cheating their way through emissions tests, and the cost to get the issue fixed will cost them billions more.

The automotive manufacturer used what is being called a ‘defeat device’ to trick emissions tests into thinking that certain cars met emissions standards. But don’t bother hunting around your car for this device – because it isn’t a physical object at all.
The defeat device is, in fact, software, and how it works is like so:

How the Volkswagen defeat device works

Cars fitted with the so-called defeat device can detect when an emissions test is being carried out on a rolling road. The speedometer, steering wheel sensors and air pressure sensors all send data to the engine control unit that recognises that it is under test conditions, and that is when the defeat software comes into play.

When the defeat software detects rolling road conditions, it switches on what Volkswagen are calling ‘dyno calibration’ which alters the working of the engine to reduce emissions and therefore achieve compliant emissions results, yet under normal vehicle operation, it switches to a separate ‘road calibration’ software that’s far less effective, and according to the EPA (Environmental Protection Authority), the simple switch from ‘dyno’ to ‘road’ increased emissions of NOx by a factor of between 10 and 40 times above compliant levels.

What the Volkswagen defeat device does

It’s unclear at this stage exactly what changes ‘dyno’ calibration made to the operation of the cars affected. What we do know is that the EPA says that it was the NOx filter whose behaviour was changing when ‘dyno’ calibration was running and if that is indeed the case, then it’s actually quite simple as to how VW were cheating their way through tests:

Diesel cars use a fluid called urea that’s pumped into the exhaust system to reduce the amount of nitrogen oxide, or NOx, that’s released into the atmosphere. Upon detection of an emissions test, more urea is pumped into the exhaust system to reduce emissions.

Now we know what you’re thinking – that urea sounds like a great thing and manufacturers should be using this magic liquid to make diesels cleaner – but here’s the thing; it’s simply not sustainable. Under normal driving conditions, the fluid would run out too quickly, burning at a rate faster than even the most uneconomical diesel engines on the market burn through their diesel fuel. And installing an additional urea tank the size of a fuel tank simply isn’t feasible – especially given the high cost of urea (it would be unaffordable).

What’s next for Volkswagen?

What’s next for VW is anybody’s guess. They are ripe for more and more negative press as more revelations come out about the company knowingly and intentionally breaking the law to increase its own profits at the expense of the environment. What we want to know is just how widespread the use of defeat software is in the automotive industry right now. It can’t just be Volkswagen AG doing this, can it? And if they are, then how is everybody else able to create diesel engines that are so environmentally-friendly while VW aren’t?

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