Reply to post: Re: Solve this at the source

Dyson to build electric car that doesn't suck


Re: Solve this at the source

"However, given that car exhaust in the USA has been cleaned up pretty well, it's much less of a problem than it used to be. And we don't allow tetra-ethyl-lead in the fuel any more."

50 odd years ago, professionals in public health, meteorology and transportation noticed how cars were creating smog in California. California was a good place to analyse the problem because it has a variety of warm climates and geography. CO and CO2 were observed to be problem vehicle emissions but nitrous oxide was viewed as the biggest one. If you burn a pure hydrocarbon perfectly, the result is CO2 and water. In the imperfect environment of an internal combustion engine, you produce NOx as well.

Transportation engineers worked with engine designers to create lower compression engines (and associated fuel) and exhaust catalysts. Internal combustion engine NOx was reduced but the CO and CO2 went up a bit. But lower compression engines are less efficient and the environmental consideration switched to CO2 emissions, so why not bump up the compression ratio (and combustion chamber temperature) and fuel efficiency whilst fiddling the NOx results?

It's a target culture problem. To meet one target, manufacturers cheat on the ones which nobody is monitoring. It is a changing dilemma and there is no quick solution.

Smart people may be asking why NOx has become a UK problem in recent years: it's how we design our cities. NOx will break down harmlessly in the UK countryside but not in sweaty cities. Where we build narrow streets surrounded by tall buildings, NOx isn't taken away in the breeze. Underground electricity sub-stations and air conditioning units mean that street temperature is artificially high. We don't see smog but humid street air becomes a bit nasty.

How to fix things? Not a clue, but it won't be fixed by focusing one one aspect of the problems. And we need to be seriously distrustful of efficiency and performance claims.

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