Re: VW : Thu Oct 08, 2015 4:03 am
Quite apart from all the hysteria, finger pointing and basically "throwing a dead cat on the table", surrounding the VW revelations, is the stupidity in expecting engine emissions recorded on-test to be replicated in "real-world" driving conditions.
When an engine is submitted for Type Approval emissions testing, it is tested on an engine dynamometer, programmed to replicate different drive cycles. The test is a multi-thousand stage programme and although different stages are included for different vehicle types (passenger car, commercial vehicle, bus etc), it is common and standard across different engine manufacturers. It is not there to show what actually comes from the tailpipe in "real world" application, it's there to provide a minimum standard to achieve and also to make comparisons, so that consumers can make a more informed choice.
The problem with "real world" testing is that one "real world" is never the same as another.
This whole charade is based around comparing apples with oranges