units of power

I've noticed that some engines are rated in terms of ps, not hp or kW. Anybody know what this stands for?

Originally posted by Dshaft96
I've noticed that some engines are rated in terms of ps, not hp or kW. Anybody know what this stands for?

ps = pferdstarke (not totally sure of the spelling)

That is German for horsepower. It is mesured slightly differently from US hp measurements. It's pretty damned close though.

Pferdstarke is correct, I speak German. Pferd is a horse and Stark(e) is strength or power. I believe that the difference is the difference between SAE horsepower and what ever the Japanese use (its only +/- 2% or something like that)

Originally posted by FlossinPrimera
Pferdstarke is correct, I speak German.

Ich spreche ein bisschen, aber nicht so gut. Ich habe viel fergessen.

Mainly I couldn't remember if the spelling was correct.

Originally posted by P10DET

Ich spreche ein bisschen, aber nicht so gut. Ich habe viel fergessen.
I speak none at all but I have this: http://world.altavista.com/sites/nzen/pos/babelfish/trns
Ain't modern technology great:)

Originally posted by T4 Primera
I speak none at all but I have this: http://world.altavista.com/sites/nzen/pos/babelfish/trns
Ain't modern technology great:)

Hehe. This is way off-topic, but what the hell. :D

I've used that a few times. But, it can't help you when you visit Germany. Of course, when I was there, virtually every time I spoke to someone in German, they spoke back to me in English. I guess my German sucks. Hehe. But, I could get around and occasionally do OK.

I've been meaning to join a German Nissan Club's message board and use that to learn to speak fluent German.

Once I get German down, I hope to learn to speak Japanese. That's down the road though.

OK guys,

since horsepower Units are used almost at will, here is (to the best of my knowledge) the untis and their relationship. Lets keep PS as the "base" unit here.

PS = Pherdstärke (as the german-aware people have pointed).
CV = Cheval Vapeur.

1 PS = 1 CV
These two are used interchangeably around Europe. Apparently there exist a very common "nationalistic" attitude in Europe that leads to an extreme "We did it first" attitude. For example, a german friend of mine once asked me if I had a set of IMPUS (or something) wrenches. After a "fruitful" discussion he let me in the "common" knowledge that ALEN wrenches were first made and used by germans and their real name is/should be IMPUS!!!

HP Metric = HorsePower Metric
1PS = 0.9863 HP Metric (in an attempt to consolidate units, reduce confusion and tone down the "we did it first" syndrom)

HP = HorsePower
1PS = 0.9863 HP

KiloWatt = 1000 Watt (better Power unit for international standard, consistent with other "modern" power units)
1PS = 0.7355 KW

HP Electric is used for Power Generator outputs.
1 PS = 0.986 HP electric.

The terms BHP and SAE HP refer to measurement of HP usually at the weels and the flywheel respectively.

Chris

Originally posted by hpro123
The terms BHP and SAE HP refer to measurement of HP usually at the weels and the flywheel respectively.

You had full marks up until that point.

bhp = brake horsepower

It refers to hp at the flywheel as measured on a brake dyno. A brake dyno connects to the flywheel and has as variable brake, usually controlled by water flow. The engine is run at a certain constant rpm with the brake is adjusted to hold it there. Basically the engine is run wide open with the brake controlling the rpm. Torque is measured at the brake and converted to horsepower since horsepower is a direct function of torque.

SAE hp generally refers to SAE net horsepower measured with all accessories and exhaust hooked up to the engine. This is in contrast to SAE gross horsepower that is measured with no accessories hooked up to the engine (e.g. water pump, PS pump, alternator, etc.). Up until the early 70s it was common practice for manufacturers to quote SAE gross hp since it was always higher and there was an hp race going on. This figure is rather misleading and thus the SAE net number became the standard by law for manufactuers to claim.

HP measured at the wheels is generally measured using an inertial dyno that measures the time it takes to accelerate a known mass to calculate torque and hp. The hp numbers from an inertial dyno can be misleading if you don't understand this. For instance, a low mass flywheel or set of pulleys will show a hp gain on an inertial dyno when in fact they add zero hp to an engine. OTOH it does give you some idea of the affect they will have on acceleration.

Thanks Geo!

In addition to supplying me with nice & correct info you proved my until now unverified assertion: "When in doubt, post something ambivalent and GR will come to the resque"! :D

Chris