Quote:
Originally Posted by Treker4747
But, my plan is to introduce a hairdryer to the air-intake. I'd like to get the biggest hairdryer I can, plug it into the beefiest inverter I can, and hope the alternator is as strong as I think it is.
And just have the hairdryer set to "high" and blowing into the air-intake piped in somewhere close to where the filterbox is under the hood.
Any thoughts on how or if this could work?
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Thinking outside the box, is good. So I want to congratulate you for thinking about this.
However, as another poster mentioned, the electrical power for this would kill you, even if everything else about this plan worked. The thing most people forget, is that virtually all electrical power from a car, ultimately comes from the ALTERNATOR. And where does the alternator get it's power from? You guessed it, the alternator gets its (mechanical) power from drag on the gas engine (i.e. lower fuel economy)!
NOTE: This isn't just theory. You can actually measure (or even "feel", if the wattage is high enough) the extra drag on the engine, due to using more electricity in a car! And in fact, I've actually been able to usefully increase my FE (in my CRX) just by lowering my electrical power usage (by such means as replacing the standard car bulbs with energy efficient LED modules, running power using fans less, etc).
So what do the numbers say? Well, the "rule of thumb" I seem to remember, is that 1 horse power of drag is approximately equal to 700 watts of electricity _IF_ your generator was 100% efficient (and car alternators are not even close to 100% efficient, nor are "power inverters" for that matter). So assuming your hair drier used approximately 1400 watts to run (and a lot of hair driers use more than that on high), you are talking 2HP+ minimum drag (likely AT LEAST 3HP in practice, due to less than 100% efficiency).
And this is drag OVER AND ABOVE any power the engine generates to move the car forward! This drag is just to power the hair drier, nothing else! And this is what the laws of physics say HAS TO HAPPEN, it's not just a matter of engineering this well, it's the physical limits of what you are trying to do (i.e. the electrical energy for that hair dryer has to come from somewhere, it's not magically created, and in a traditional car it comes from extra mechanical drag on the gas engine). So there is no way to "engineer around this", unless you had a totally different source of electrical power (a big plug-in battery pack, perhaps?), in which case you are really just making a weird sort of electrical-gas hybrid car. Otherwise, you are pretty much stuck with these numbers.
So the bottom line, is that you will pay a 3HP+ loss of power (possibly 6HP or more, depending upon the efficiency of your components), just to run the hair dryer constantly. And this loss of power will hurt your FE a fair amount (the effect on the car will be similar to what would happen if you had your brakes partially engaged all the time). And this loss of FE is almost certainly going to be greater than any FE gains you could get by warming your car intake air. So you would essentially lose FE overall, not gain it.
OTOH you might be able to boost FE, if you were to find a source of heat that doesn't require nearly so much energy to tap into. For example, using some of your "waste heat" (from the car's exhaust system), via a "heat exchanger", to heat your car's intake air. I'm not saying even this would gain you FE in your car (it may or may not, depending upon how your car responds to warm air intake), but at least an approach using "waste heat" avoids the huge power losses associated with generating heat from electricity in a car (so it actually has a chance of helping overall, unlike the hair dryer, which would use too much power to make it practical)...
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