Lowest RPM and V6 engine or any engine can go
Lowest RPM and V6 engine or any engine can go
(OP)
Does anyone know the lowest RPM that a combustion engine can go?
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Lowest RPM and V6 engine or any engine can go
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Lowest RPM and V6 engine or any engine can goLowest RPM and V6 engine or any engine can go(OP)
Does anyone know the lowest RPM that a combustion engine can go?
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RE: Lowest RPM and V6 engine or any engine can go
RE: Lowest RPM and V6 engine or any engine can go
I'm sure you meant internal combustion, though, so those 100 RPM slow speed 2-stroke diesels would be the slowest I can think of. They are design rated to run at 100 rpm which means they can overspeed to 110-120 rpm at the most. They don't idle because they are direct drive, but I'm sure they operate at speeds as slow as 50 rpm or maybe slower.
RE: Lowest RPM and V6 engine or any engine can go
RE: Lowest RPM and V6 engine or any engine can go
Malbeare
http://www.sixstroke.com
RE: Lowest RPM and V6 engine or any engine can go
Several of the natural gas/methane V-12 and V-16 Co Gen engines used in the generation of electricity could run in the 100 rpm range but were usually set up to operate at closer to 600 rpm in turbo charged form, at least the units in Orange County and in Santa Barbara County, the ones I worked around.
Rod
RE: Lowest RPM and V6 engine or any engine can go
Well OK, I'll tell you: 150 rpm, so it /has/ to be able to run at least that slow, reliably. There are practical installation reasons (driveline resonances etc) why automotive engines are not run more slowly, but in principle there isn't really any particular reason why even quite standard engines could not run very slowly.
One very useful thing would be to be able to run engines up from idle to red line and use ALL of that speed range. This is feasible for a prototype, but would need a lot of changes in various sub-systems.
Cheers
Greg Locock
RE: Lowest RPM and V6 engine or any engine can go
RE: Lowest RPM and V6 engine or any engine can go
If a 2 hp starter motor can overcome the waterpump, oilpump and alternator friction at 150 rpm then I don't see why a 100 hp engine operating at 1/40th of its rated speed cannot do so.
Really, these things aren't hard to test for yourself, why not do the test before writing notes like that?
Cheers
Greg Locock
RE: Lowest RPM and V6 engine or any engine can go
These observations are from working on pre 1920 cars, which sometimes need to be crank started, and often only have a 2 speed gearbox, and from working on ski boats with dog clutches, and tow cars.
Engine configuration has a minor effect, mainly as it effects port angle for a good downhill shot at the valve, hence tilted or slanted in line is better than upright in line, "V" configuration is better again and horizontal is best.
This applies mainly to carby engines as an injection nozzle aimed straight at the back of the valve will deliver all the fuel to the cylinder every time, no matter where the manifold runs.
The greater the number of cylinders, the less the need for flywheel weight, as 4 or more cylinders always has one on the power stroke, and 6 or more always has one in the effective part of the power stroke.
Longer stroke also helps as it increases piston speed at the specified rpm.
Just my ramblings, for what it's worth
Regards
pat
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RE: Lowest RPM and V6 engine or any engine can go
RE: Lowest RPM and V6 engine or any engine can go
Point is, the slow idle. If this engine hadn't had such a slow idle, I could not have withstood the energy of the spark ignition in order to pull the trick on others.
Great fun for a college kid, and testimonial to how slow an internal combustion engine can actually idle. (It wasby the way, a v-4 gasoline engine.)
rmw
RE: Lowest RPM and V6 engine or any engine can go
we used to have a 4wd forklift on the farm. It had some galumphing great I8 in it.
To start it we decided which cylinder was at TDC, took the plug out, tipped some fuel in, put the plug back in, and switched the ignition on.
Cheers
Greg Locock
RE: Lowest RPM and V6 engine or any engine can go
rmw---I 'sparked' my friends, unsuspecting passerbys. bugs on the fender, etc. with the same technique using a plug on my old 1949 Mercury. I was only 18 and the 'jolting' wasn't too bad after the FIRST hit. Crazy kids!
Unclesyd---I saw a one cyl (Perkins, I think), similar to the Buddah you mention, on a fishing boat in Texas as a kid. All I remember is it sounded like a "hit and miss" engine. Just kinda 'chug, chugged' along.
Rod
RE: Lowest RPM and V6 engine or any engine can go
I remember nosing it into a tree at idle, it would just stand there and --- chug -- pop - pop -- and just spin the rear wheels a partial rev at a time, with each pop. RPM? no guess probably pretty darn slow.
ietech
RE: Lowest RPM and V6 engine or any engine can go
Rod
RE: Lowest RPM and V6 engine or any engine can go
I got a laugh out of your reply to my post. You are right. That first jolt was the hard one. once you got your mind right, so as to be able to take hold of the plug wire initially, then the rest of it was all fun.
I would be afraid to do it at my age, now, fearing that it would act like some kind of pacemaker and do strange things to my ticker.
rmw
RE: Lowest RPM and V6 engine or any engine can go
After my last post I did a Google search on the subject and found some really interesting sites. Seems I created some new curiosity in myself. Type in "Johnny Popper". Some of the links within the websites listed in the search results have items for sale.
In addition I came accross some great sites regarding vintage/antique industrial engines that others posting here might be interested in reading about. Old LeGrange, Briggs, and others.
All very slow RPM's for those interested type antique engines or vintage engines.
Regards,
ietech
RE: Lowest RPM and V6 engine or any engine can go
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Lowest RPM and V6 engine or any engine can go
RE: Lowest RPM and V6 engine or any engine can go
Case in point: I took an old irrigation engine, a Chrysler 413 (hey Evelrod, remember those?) and had problems running it down to 400 rpm without very erratic performance (no-load). Installing a simple Propane carburetor (Impco 200 if anyone cares) and it easily idled down to 200 rpm, where I suspect the motoring friction losses exceeded the power production.
One thing more to add. The engine rpm has little to do with spark intensity (contemporary distributor, either electronic or contact point primary, not the magneto system), as I read in “rmw’s” post above. What you may have been feeling is one impulse every five or ten seconds.
Franz
RE: Lowest RPM and V6 engine or any engine can go
*exit stage left before bottles and tomatoes start flying*
RE: Lowest RPM and V6 engine or any engine can go
Rod
RE: Lowest RPM and V6 engine or any engine can go
RE: Lowest RPM and V6 engine or any engine can go
Yes, done so many times. In one of my former personal vehicles (import 4 cyl 2.4L w/ std) easily idles down to 300 rpm. Low speed engine performance was also smoother than on gasoline.
Using an optical engine, and watching the air-fuel mixtures propagation and homogenization when changing from liquid fuels to vapor fuels also confirms this. If you can change fuels in steady state mode, it is readily apparent. In some cases, you can even hear the difference.
Next, using pressure transducers, vapor fuels show a lower overall pressure during combustion, but the combustion pressure remains longer on the power stroke than with gasoline.
Franz
RE: Lowest RPM and V6 engine or any engine can go
RE: Lowest RPM and V6 engine or any engine can go
Vapor fuels, LPG or Methane, are combustible hydrocarbons, water is not. LPG and Methane have higher octane ratings than conventional gasoline. It’s the octane that allows for a longer burn duration, thus a longer combustion pressure, albeit lower, than gasoline. Both LPG and Methan have lower BTU’s than gasoline, thus a lower peak combustion pressure.
Water injection tends to suppress combustion temperatures and pressures. It takes chemical energy to convert the liquid water droplets to steam. There is relatively little (if any) energy derived from the steam expansion process. The chemical energy required to convert water to steam is derived from the air-fuel mixture. Consider the first and second laws of thermodynamics.
My experience has shown that if water injection is needed, there is a shortcoming somewhere in the engine dynamic process. Either compression is too high for the fuel provided, the fuel is of an insufficient octane, the timing is too aggressive, the air-fuel mixture is incorrect, the combustion chamber is not set up properly, and so on.
Before I get lambasted for saying water injection is bad, there are circumstances where water injection can indeed prove beneficial, such as in stationary turbine power generation systems.
Franz