Join Date: Jan 2009
Location: North-West Blighty.....
Vehicle: '16 C250d AMG Estate Premium+ Designo Hyacinth Metalic
Other Toys: Guitars... :-) Formerly '08 SLK200 6sp Palladium
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The issue is tailpipe NOx emissions. Trucks typically have de-NOx after treatment systems, e.g. Selective catalytic reduction or SCR whereby AddBlue (Urea) is injected into the exhaust stream that then reacts over a catalyst to minimise the emitted NOx. In the U.K., there is no requirement to fit such systems to passenger cars and they can pass the current emissions regulations without them being fitted.
BTW - Gasoline cars have de-NOx after treatment in the form of a 3-way catalyst, which works because of different exhaust gas chemistry (compared to diesel exhaust).
So, if a truck with de-NOx after treatment produces ultra low emissions, say 10mg/km of NOx, where a passenger car without after treatment produces 100mg/km (still a very low level of emissions), the car produces 10x the emission level. If the truck produced 1mg/km, the same car would be deemed to be 100x more polluting, which is a great headline but doesn't mean diesel cars suddenly became worse polluters. So to some extent, this is a bit of a crock! Current diesel vehicles are massively cleaner than those of 10-20 years ago.
IMHO, there is big politics behind this in so far as there is a political desire to increase the uptake of electric cars (which really only make sense in cities in my view) to improve local air quality. However, the budget required to provide the infrastructure (charging points, power stations etc..) would detract from other big programmes like health, defence, education, public transport and so on. So at the moment when the transport minister is trying to get funds to put in charging points and stuf for electric cars, everyone else around the table says 'Who for? There are only a couple of dozen electric cars on the road! Meanwhile, we need more money for hospitals, tanks, schools etc...' Transport guy doesn't get a penny.
In addition, there is a lot of pressure on the middle distillate materials that are used to make diesel, so lighter materials that would otherwise go to making gasoline have to be processed into diesel.
So, by making diesel cars the bad technology, gets folks in the country side to go gasoline, the folks in the city get charged a fortune to have diesel so want to go electric. Demand for gasoline goes up (well demand for diesel falls), demand for electric vehicles goes up. More money for power stations etc. etc.
It's a proper wind up. What should have happened is that all passenger cars should be fitted with de-NOx systems in order to be compliant with prevailing regulations. Nevertheless, the over demand on middle distillates is an issue because it also competes with aviation (jet) fuel/kerosene. So weening us off diesel is inevitable, it's just a shame that the modern Diesel engine is so good.