heating intake air to improve mpg?
heating intake air to improve mpg?
(OP)
been curious for a while about how much fuel economy can be gained by having an engine intake from a hot spot in the engine bay. I'm sure there have been many experiments in this field, can anyone point me in the right direction, or give thoughts. The idea is to have two intake pipes; one cold air, the other a hot air when absolute power is not needed, and a way to switch between the two.
thanks
thanks





RE: heating intake air to improve mpg?
Regards
Pat
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RE: heating intake air to improve mpg?
I'm not aware of a closed loop fuel injected system that uses this system; that tells me that the main benefit was open loop carburetion accuracy; evidently the fuel economy improvement for fuel injected systems is minimal, or they would be using it.
RE: heating intake air to improve mpg?
As far as I know, that system was a quick warm up device to improve drive ability and reduce cold star emissions.
It could have a very minor impact on fuel economy by reducing the time it was necessary to run the choke.
Regards
Pat
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RE: heating intake air to improve mpg?
http://www.metrompg.com/posts/wai-test.htm
Simple question. Given that it is very cheap to blend warmer and rather cooler air do you not think that manufacturers would have done this rather than indulging in variable cam timing etc if it had a worthwhile effect on mpg?
Cheers
Greg Locock
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RE: heating intake air to improve mpg?
And I'm sure somebody will correct me if I'm wrong, but doesn't warm intake air lower the overall thermodynamic efficiency of an engine?
ISZ
RE: heating intake air to improve mpg?
http://www
RE: heating intake air to improve mpg?
RE: heating intake air to improve mpg?
The metrompg link summarizes the small difference well.
RE: heating intake air to improve mpg?
The pro was better part throttle efficiency, the con was melted parts and hot fuel handling disaster.
RE: heating intake air to improve mpg?
For difficult to evaporate fuels, or in very cold climates, preheating may help, but for highly volatile fuels, in warm weather you get virtually 100 evaporation anyway, so preheating simply reduces VE which requires wider throttle opening which reduce pumping losses.
I am ure this has all been said before.
Regards
Pat
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RE: heating intake air to improve mpg?
There is definitely an optimum air temp. My guess it's right about 130-140 f. I say this because of many years of forced induction product design with an emphasis on emissions standards and meeting strict California smog testing standards. I find this window to be the optimum for best (low) HC and reduced nox emissions.
RE: heating intake air to improve mpg?
RE: heating intake air to improve mpg?
RE: heating intake air to improve mpg?
Robin.
RE: heating intake air to improve mpg?
RE: heating intake air to improve mpg?
RE: heating intake air to improve mpg?
I downloaded the calibration data from a ROM on a 1987 Dodge Daytona 4 cylinder (batch fired injectors) and looked at the values using Chem2 software. I noticed the computer automatically richens the A/F mixture when the coolant is cold. As the temperature of the coolant increases, the fuel enrichement decreases. At around 118 deg F the fuel enrichement levels off and does not decrease anymore. I imagine my Saturn has the same type of deal. Another interesting thing is the Daytona doesn't go into closed loop until the coolant reaches 66 deg F and a delay time of 20 seconds is reached (it does use a heated 02 sensor). I am half way to work by then (when the outside temp is around 30 deg F)!
I think if i had a longer commute to work, i would see less of a mileage improvement with the warm air intake (WAI). Since my commute is short my engine is not warmed up fully by the time I get to work. The warmer air probably helps vaporization while the intake and head are still cool. Once everything is warmed up, the WAI probably makes little difference in mileage. Keep in mind that my car uses sequential fuel injection, not a carburator, and I'm still seeing an improvement.
It really hasn't made a very noticeable decrease in performance during summer days, so I don't worry about having a valve to turn off the warm air and pull in cool air on hot days. I also hear no pinging and no noticeable spark retard (using a Scangauge II).
RE: heating intake air to improve mpg?
Almost all wheeled and tracked machines burned JP-8, the same fuel the C-130 use when bringing in our supplies on a less than frequent basis. 2 Block heaters for starters on some engines! There were adaptations of mullion heaters normally used on fridges to defrost them on the transmission pan and on the Tran's axles plus difs. All were insulated and the power draw on some was a 20 amp circuit breaker. There was also an interior warmer in most of the ford F-350's Diesel crew cabs as well.
All vehicles had 3 flaps that open on the radiator blankets on the exterior of the front grill increasing heat to the engine. Vehicles burned more fuel idling than actually moving on the 45 Km of roads in the area. Part of the reason it is 24 hours nighttime in the winter for almost 6 months, so you leave your lights on. This to see if polar bears and wolfs are in the area, your key safety concern.