"E. Julius" (soonerfrommi)
03/08/2015 at 20:45 • Filed to: None
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"E. Julius" (soonerfrommi)
03/08/2015 at 20:45 • Filed to: None | 0
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I'm reading Proficient Motorcycling on the suggestion of McMike, and I came across this curious quote regarding the effects of water in an engine intake during rain:
Don't worry about your engine drowning from too much water being thrown around in the airstream. Water is vaporized during intake and turns to steam during the heat of combustion, and steam can actually help increase horsepower .
I'd never heard this before, so I tried to imagine how it might work. My first reaction was that the water would just be taking up space, reducing the concentration of the fuel air mixture. Then I thought maybe it has to do with cooling the intake charge, like an intercooler? Maybe if the change would be registered by an intake sensor a computer controlled engine could change some parameter like the fuel mixture? I really don't know.
bob and john
> E. Julius
03/08/2015 at 20:49 |
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your right on the cooling. the water will absorb some of the heat. note they are kinda refering to rain and what not. they ARENT saying to ride through 3 foot deep puddles and sloshing it inside the intake.
the wording is stupid. dont get to hung up on it.
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E. Julius
> bob and john
03/08/2015 at 21:00 |
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Yeah it's from the section on riding in the rain, and also followed by pretty much exactly what you just said (although I doubt anyone would think cruising through a pond would give them a power boost!) I just found it odd since I've done a lot of research on engines and never read anything about steam increasing horsepower.
Edit: or more correctly, about the effects of water vapor in an engine.
Biggus Dickus (RevsBro)
> E. Julius
03/08/2015 at 21:07 |
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I could see steam either cooling your intakes or producing pressure of its own in the cylindr, leading to higher compression ratio and therefore more power.
Sweet Trav
> E. Julius
03/08/2015 at 21:07 |
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Intake charge cooling. as a general rule, for every 10 degrees F you cool the air you will make 1% more horsepower. HOWEVER the reason why you make more power is not due to lower temps, but DENSER air.
Conversely, on a turbo application in the inclusion of water or methanol can increase the air charges ability to resist detonation. Which can allow you to run more boost or up the ignition timing.
The only way that it is going to make more power is if the engine management system knows it has a cooler, denser intake charge and will add more ignition timing, otherwise nope.
So generally I'd say that quote is technically correct, but in the real world you wont notice any more power, unless your engine can compensate for the inclusion of moisture, and even then you're talking less than a percent increase in power.
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bob and john
> E. Julius
03/08/2015 at 21:09 |
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well, think about running meth ingention. similar idea.
like I said, wording is stupid. there was another book...101 things every biker should know or something like that. That was also a GREAT book
claramag, Mustaco Master
> E. Julius
03/08/2015 at 21:18 |
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Didn't the old Saab Turbo use water injection in lieu of an intercooler to keep air temp down?
"Increase horsepower" sounds weird. Maybe "reduce tendency to ping, allowing higher compression or timing advancement, thereby allowing an increase in hp" would've been better
desertdog5051
> E. Julius
03/08/2015 at 21:23 |
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This may help.
http://www.autoblog.com/2015/03/06/bmw…
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E. Julius
> Sweet Trav
03/08/2015 at 21:35 |
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yeah that's what threw me off—I couldn't see anyway for an average motorcycle engine to dynamically adjust to this situation. Seemed strange. Good reply!
samssun
> E. Julius
03/08/2015 at 21:41 |
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Water will only vaporize if something makes it, like heat or expansion. A water or methanol (same thing, plus energy) injection kit sprays a fine mist so you have lots of surface area to absorb heat. This lets you run higher boost or compression.
I don't see how steam itself would directly increase horsepower...you can heat water until it expands as steam and use that as your working fluid to push the piston, but just putting water in your engine doesn't increase the actual amount of heat (= work, = power) you have available.
pip bip - choose Corrour
> E. Julius
03/08/2015 at 21:55 |
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i'm clueless.
Snuze: Needs another Swede
> E. Julius
03/10/2015 at 17:43 |
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Just stumbled on this, but found it interesting and it reminded me of something.
Some university, I think it was in India, developed a "6-stroke" engine that used water injection as a means of energy recovery. Basically it worked like a 4 stroke engine but after the exhaust cycle and before the next intake cycle they injected some water into the cylinder. The waste heat leftover vaporized the water into steam, which expanded and provided a secondary power stroke. Then they exhausted the steam, sucked in a fresh air/fuel charge, and repeated the process. As I recall it was somewhat more efficient than a normal 4 stroke engine, but suffered a major problem - the steam easily lifted oil off the cylinder walls, which lead to greatly increased cylinder wear.
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E. Julius
> Snuze: Needs another Swede
03/10/2015 at 17:49 |
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Interesting idea!