Reports are in: Volkswagen recall will increase in fuel consumption and reduce engine performance

We said right from the start of our action that it’s important to remember two key things at the heart of the Volkswagen Emissions Scandal:

The second point has remained an ongoing question; what were Volkswagen so scared of happening that made them take the inappropriate decision to misrepresent their vehicles as opposed to acting fairly and being honest?

Deep down, we always knew what the reasons would be…

Vehicle performance WILL be affected by the recall, reports confirm!

We feel like saying that it doesn’t take a scientist to tell you that there will likely be an impact on how the vehicle performs once the defeat devices are, well, defeated; but the extent of the impact is now becoming clearer as investigations and testing reveal a damning truth behind what victims might expect to happen when their vehicle is recalled.

In a nutshell:

Source: David E. Foster, Phil and Jean Myers Professor Emeritus of the Engine Research Centre at the University of Wisconsin-Madison

On top of this, the assertions that Volkswagen are making as to the cost, ease, and even permanence of the fixes is being heavily criticised.

Whilst Volkswagen has dismissed some findings so far as mere “speculation” it is worth noting that testing on the Amarok (a mid-size pickup truck), which forms a part of the recall, has found the vehicle allegedly still failing NOx tests even after the refit.

The science bit…

According to the reports we have seen, and based on information we were already aware of, there is what is known as a Soot-NOx trade-off; soot being carbon. In simple terms, NOx emissions can be reduced by lowering the temperature as both are related. This can however reduce engine performance and can increase fuel consumption as engines are not running at optimal efficiency in lower temperatures.

On the other hand you can have optimal combustion which raises engine temperature but increases NOx emissions; but, as the engine operates more efficiently, less fuel is consumed.

It is a generally accepted scientific principle that you can’t have it both ways; hence the “soot-NOx trade-off” concept.

NOx and the temperature are directly related; i.e. higher temperatures = higher NOx, and vice versa. This is how NOx can be reduced by lowering optimal combustion at the sacrifice of greater fuel consumption and reduced performance.

This is the short of it, but it should help to give you a better understanding as to how reducing NOx can increase fuel consumption and reduce engine performance.

If this transpires to be correct following the recall and refits, owners can expect higher costs and reduced performance which in turn will likely reduce the value of the vehicles more so than they have already been reduced by the downturn in sales as a result of the scandal.

Ultimately, the evidence presented so far shows that what victims have paid for will not be what they are getting post-refit. It seems that reducing NOx can only be effectively done by either sacrificing vehicle performance, or cheating the system.

Sadly, Volkswagen chose to cheat…