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![]() Capt. Geoffry Thorpe wrote: Water can reduce the charge termperature as it evaporates in the cylinder which can increase the charge mass a little, but mostly it improves knock resistance by cooling the charge and increasing the specific heat of the charge mass. But to really take advantage you have to either increase the compression ratio or boost. NOx is recduced somewhat since the peak temperatures are reduced. If you are trying to change the fuel chemestry to get more energy out - you have to put energy in. Lose - lose. If you are trying to make the fuel burn "better" to make it "all" burn - gasoline burns just fine. Unburned fuel in the exhaust comes from three primary sources - mixture that is pushed into the crevices around the piston / sparkplug / etc. where it can't burn (it comes out of the crevices during the exhaust stroke), mixture that is quenched at the cylinder walls due to heat loss. And excess fuel from running rich. The bulk of the charge mass burns just fine. Cow magnets, magic additives, whatever aren't going to change any of that. Ah but the thermodynamic efficiency of a heat engine increases as the compression ratio or temperature ratio increases. The issue is not how to get more heat out of the fuel, it is how to convert more of the heat to mechanical energy. -- FF |
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