Inline fuel heaters?

[jtanguay]

Maybe you could put some peltiers with fins in the intake so you could flick a switch and heat the air when starting. Though people usually think of them relating to cooling, they output 150% more heat than the energy you put into them.

and just reverse the polarity in the summer to get some cooling  :twisted:

[jtanguay]

Fuel should be cool for higher density, heating would actually lean out the cylinder air/fuel mixture.

Wouldn't a lean fuel mixture be an advantage for fuel economy, But bad for power?

maybe... but the car would run like crap.  it might affect timing which then adversely affects fuel economy anyways.  TDI's could compensate for this as the ECU gets a signal for when the injectors open (which might yield a very small decrease in fuel consumption).  IDI's and mTDI's do not compensate for fuel density and therefore are affected the most.

but... as these injection pumps were designed to use the diesel fuel to 'cool' the injection pump, it just doesn't seem like a good idea to add more heat to the equation.  although there are many people out there running really hot veg oil through their pumps with much success... could be due to the fact that veg is such a good lubricant?  i guess it could be viewed as running thicker oil in a race engine to control heat and wear under extreme conditions? (20w50 oils etc)

i have a couple 350 watt peltier junctions i'd like to mess around with... all i need is access to a lathe to machine out a block out of aluminum with two flat sides for the junctions, and a little route for the fuel to flow through.  for hot days that fuel could be cooled by at least 10C as i've played with the 350 watt junctions and they get mean cold pretty quick.. with a big enough heatsink on the other side it could probably give frostbite fairly quickly  :lol:

[bigblockchev]

I'm thinking that at 350 W the peltier is going to draw 30A or so which is a lot of current. Possibly taking more energy to produce than the potential increase in power it might yield. It would be interesting to develop an objective method to test this theory. Cheers Dan

[jimfoo]

That's .2 HP plus any losses in generating it. So it wouldn't need to help too much to make more power.

[jackbombay]

Fuel should be cool for higher density, heating would actually lean out the cylinder air/fuel mixture.

Wouldn't a lean fuel mixture be an advantage for fuel economy, But bad for power?

  Hotter fuel (less dense) will lessen the amount of energy injected per volume of fuel injected, so the only difference is that you have to push the pedal ever so slightly further down with hot fuel compared to cold fuel.

  Hot fuel may atomize better due to lower viscosity and thus burn better creating better efficiency, but that's going to be a pretty slim difference I think.

[bigblockchev]

Jim it actually takes a great deal more than .2 hp to generate 30A. In days of old American Iron, guys would use a cutout switch to disconnect the alternator field at full throttle because they could actually notice a difference in the acceleration by doing so. The typical alternator in those days was a 45 Amp  Delco  or maybe 60Amp if you had AC. If you have ever tried one of those exercycle generator gizmos   that they use to demonstrate how much pedaling energy it takes to light a 100W light bulb it becomes clear that   the efficiency of mechanical to electrical conversion is not high. The amount of heat that you could remove from the fuel is limited by the gellpoint of the  fuel, the actual mass of fuel injected per revolution is quite small compared to the mass of air being pumped through the engine. The temperature  drop that you would be able to produce by cooling the fuel would be fairly small  so the net gain would be minimal as I see it. Much easier to go with an intercooler to decrease the charge air temperature. Cheers Dan