Quote:
Originally Posted by cbaber
Thats the idea for more power but we are after more MPG. Cold, dense are will make the ECU use more fuel, resulting in more power. In our world we want the opposite. Warmer air would require less fuel to burn, making less power but more MPG.
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Yes, but it's less thermally efficient to pre-heat the intake air (or petrol/gas).
However, prior to directly-injected/near-TDC injection engines the ambient air temp is a measurable influence on capability of the petrol to mix completely with the air. - This is why heating the charge is good, ie. the -ideal- thermal efficiency drops a little but it's negative effect is far outweighed by the gains of better fuel evaporation.
I have been shown (back-of-the-envelope) that trying to get this effect by heating fuel is a no go. Petrol just has too little heat capacity (ie. the very fact that it evaporates so easily is the problem). So if the petrol is the medium that's carrying the heat it will be totally swamped when it meets the coldness of the air.
<though I'm still not 100% convinced I must say!>