Bad education

Noticing that How, or rather How II, was back on the telly, I thought I'd have look in, it was always interesting.

Well, the first programme I caught was a little depressing. The presenter proudly announced she was going to tell us how car, or internal combustion engines, worked – and then proceeded to get it wrong virtually from the first sentence she uttered.

Something along the lines of "engines work by using the power generated by a series of explosions" or something similar. It doesn't really matter, as the a error was the use of the word explosions.

Internal combustion engines work by harnessing the power from a closely controlled burning of the fuel/air mix inside the cylinder. Maximum power is obtained by holding this burn just short of the conditions that produce an explosion, and this is important. Let the mixture explode (detonate or pink) and all sorts of expensive nasties start to happen. The temperature climbs, piston crowns can melt and be holed, plugs disintegrate and burn too. The explosion also generates high pressure shock waves, accelerating the temperature damage, shattering the plug and helping to punch a hole in the piston crown too. Unchecked mild cases can just cause overheating and ruin the cylinder-head and rupture the cylinder-head gasket.

Use your imagination, and there's more damage en-route to ruin an engine that explodes its fuel, rather than burning it.

And diesels still burn rather explode, even though they're designed to do so at higher pressures.

Maybe that's whythey're called internal combustion engines, and not internal explosion engines 


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