HOW MUCH HEAT TRANSFERS TO FUEL?

[Ian Anderson]

I've asked the same question elsewhere

Someone said hot fue; vapourises better - see carb engines where the hot water sysem was used t heat the carbs. Is this correct or was that just to stop the carbs icing up?

Also fuel injector design is such that the spray and atomisation is designed for better burn.

Who is right?

I get confised

Ian

[stevieturbo]

Perhaps hot fuel is better in terms of emissions etc ??? dont know really.

Carb icing is a very real problem. Even EFI TB's have heating too, so I guess they can freeze up. No other reason to provide heating there, that I can think of.

[racer]

Perhaps hot fuel is better in terms of emissions etc ??? dont know really.

Not to worry..I do!

First of all, Ian..listen to Peter and Stevie et al on playing with the fuel pressure system. For what its worth, I vote for everything they said.

Proper fueling is a process of matching fuel to the air available for combustion. In normal running, providing fuel is easy..simply a matter of increasing fuel delivery with pressure or chips or jets & needles. Air flow is the one that everyone spends so much money to increase.
Once you know what air you have, you can refine things.

Cold fuel is fuel, very hot fuel has vapor in it. Less fuel for the same amount of air means a thinner mixture..less power, even stalling. The later EFI systems (Hotwire, GEMS, Bosch Motronics) measure fuel temrpature and increase injector duration to compensate. The earlier Bosch L-Jetronic systems, without an adjustment for fuel temps, have a problem with fuel vapor. (The Australian division of LR used to have a cute add-on device, a fuel temp activated solenoid that used to increase fuel pressure when it became too hot.)

Hot engines burn more efficiently...but with less power. Modern auto engines are made to burn hot (95-102C). Colder engines (80C) produce more power and waste far more fuel.

racer