IN HINDSIGHT, motorists (your correspondent especially) should have been more sceptical about Volkswagen’s claims for its small diesel cars. Of all carmakers, VW alone had seemingly pulled off the feat of producing a small four-cylinder diesel engine (a two-litre unit known internally as EA 189) that was affordable, had great fuel economy and did not need costly processing to purge its tailpipe of unhealthy pollutants. For diesels generally, performance and low emissions are considered mutually exclusive—unless a chunk of money is spent on exhaust-cleaning gear.
Other carmakers accepted there was no easy answer to the dilemma. Nissan had tried to make a small, clean diesel fit for American roads, only to abandon its efforts in favour of a zero-emission electric vehicle (the Leaf). Honda ditched its own attempts to build a small, clean, high-mileage diesel, preferring to carry on refining its economical petrol engines instead. Toyota took one look and decided the future of clean, high-mileage vehicles lay with hybrids (the Prius range). Mazda persevered with its four-cylinder diesel engine (SkyActive-D) for the American market, only to postpone...Continue reading
Source: Science and technology http://ift.tt/1mTkHNG
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