Wouldn't the extra power possible to liberate with the cooler air be countered by the power drain from the air-con?
Oh yes. Waste of time, it's like generating electricity from the turbine that powers a fan!
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Mike Farrow
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the car makers devote a lot of attention to ensuring the air that goes in to the engine is warm as soon as possible !
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IIRC,
Cool air = more power
warm air = better economy (and possibly lower emissions ?)
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Yep
economy and emissions is the name of the game at the moment. so warm air it is !
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So is turbo intercoolers not being fitted anymore?
I recall a Diesel Shogun had one.
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Yep, you can still get them but I think mainly on high power cars like Imprezza STI's and Evo's.
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IIRC, Cool air = more power warm air = better economy (and possibly lower emissions ?)
I don't doubt it as you seem to know more than me, but could you explain how? Cold air I thought is more oxygen rich so will create a better bang per x/ml of fuel.
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I think in the 'olden days' they wanted the air warm to prevent carb icing. With injection systems that wouldn't be a porblem. Thye may want the air warm or hot but I don't know why.
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The air should be as cool as possible. As has been stated, cooler air is more dense, therefore more oxygen. Drag racers sometime put ice or even dry ice around the air intake to get it as cold as possible.
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Bad idea, the aircon has removed moisture from the air, Moisture is good for combustion.
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TourVanMan TM < Ex RF >
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2 questions
how can moisture be good for combustion??? surely the drier something is the easier is burns?
if makers do "everything they can to use warm air" then why does the air box take air from the front or side of the car..well away from the engine AND why do K and N do a 571i kit that blocks off air from the engine?
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www.storme.co.uk
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Seriously, water introduced to petrol make it burn easier. something to do with the extra oxygen in the water, and the steam of the water aiding the vapourisation of petrol.
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TourVanMan TM < Ex RF >
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Seriously, water introduced to petrol make it burn easier. something to do with the extra oxygen in the water, and the steam of the water aiding the vapourisation of petrol. ------------------------------ TourVanMan TM < Ex RF >
Cool air is denser so contains more oxygen, moisture in the air also provides anti knock properties in effect slowing the burn so the charge burns more completely. Many ECU controlled engines will make use of this anti knock feature when, for instance, driving on a cool, damp morning by advancing the ignition (petrol) or optimising the injection (diesel). That being said you can feel the benefits with any engine including 2 strokes.
Cool, damp air is better for both power and economy except on the warm up phase because it simply enables the engine to run more efficiently.
I have often wondered why vapourised water injection into the inlet manifold has not become common.
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Moisture is good for combustion in that it cools the charge of fuel/air mix and increases its density. Also water or moisture being turned to steam expands enormously and adds to the power. Do you not remember water injection in WW2 piston flighter engines? It was actaully called Water/Methanol injection SFAIK The methanol burned well and stopped the water from freezing = more power. Don't dragsters run on pure methanol?
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Water-methanol injection has also been used to increase power in turbo-prop aircraft engines. Two that I can think of are the RR Darts as fitted in the HS748/Andover, and the first Lockheed P-3A Orion engines, Allison T56-A10W. In each case the WM was used to increase takeoff power, then switched off for the rest of the flight.
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Pete M. I am ashamed to say that, despite my flying background, I did not know about water meth on turbo props. I am now none the wiser but VERY much better informed, thanks to you!
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Water methanol injection was, IIRC, fairly common on early turbojets as well as the Dart and it's Allison contemporaries. Teenage years were misspent plane spotting and well remember the fuel bowsers towing a mini tanker of "methmix" during the summer of 76.
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Oddly, a good place for an air intake is behind the coolant radiator. Although the logic of this will pass the Max Power loonies by.
When you are moving at reasonable speed, the air passing the radiator doesn't pick up too much heat, and it's temperature doesn't rise much, so it isn't a big problem. Also, the aerodynamic penalty of having a coolant intake and an engine intake in the frontal area is reduced by this scheme.
At low speeds, the air is heated by the radiator, and this warm air is ideal for economy and emissions under these conditions.
Using this scheme, you don't need PTC heaters in the manifold, thermac valves, or rattling manky vacuum operated flaps in the intake - in fact it's an elegantly simple, reliable and cheap solution.
Number_Cruncher
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It's possible to go the route of air to water intercoolers on cars with forced induction but unless the cars cooling system has excess capacity you're just going to make the engine overheat. Alternatively a system that sprays the intercooler with water can improve things if searching for every bit of power.
Steve.
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Xantia HDi.
Buy a Citroen and get to know the local GSF staff better...
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Cooler air is denser. The denser the air the more fuel you can mix with it, and hence get a bigger bang. I have to admit to not being able to tell on my car between summer and winter. Only worth it on a diesel, I'd have thought, hence the reason why they all have intercoolers.
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>>Only worth it on a diesel, I'd have thought, hence the reason why they all have intercoolers.
The intercoolers are usually fitted to turbo engines, in order to reduce the temperature of the compressed intake air. Alas, the turbo, like all compression processes, increases the temperature as well as the pressure.
For good reason, turbos are most commonly found on modern diesel engines, so, you see intercoolers on many turbo diesel engines.
Number_Cruncher
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It's possible to go the route of air to water intercoolers on cars with forced induction but unless the cars cooling system has excess capacity you're just going to make the engine overheat. Alternatively a system that sprays the intercooler with water can improve things if searching for every bit of power.
IIRC the Subaru Impreza WRX STi has a little red button that sprays water into the inlet side of the engine for that "little extra" boost as and when required.
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A 'Waterloo Boy' tractor used water in much the same way back in 1919, so its nothing new.
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Not long ago I thought I'd invented something when I wondered why nobody had introduced a refigerated intercooler. So I did a websearch and found that the idea had already been thought of and kits are available.
One system cools a tank of stored pre-compressed air that can be relesed into the intake airstream to boost power, a bit like nitrous oxide injection but tamer!
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Compressed air has been considered as a power regen option along the lines of - as you apply the brakes a clutch driving a rotary vane compressor is engaged so much of the reduction in momentum is acheived by the load on the compressor. Then when you need a bit of extra power the compressed air is released into the intake system at approx 0.5 bar above atmospheric, apparently enough to give a good few horse power for a good few seconds.
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