On Fri, 17 Mar 2006 23:31:11 +0000, Andy Dingley
wrote:

On Thu, 16 Mar 2006 03:13:05 +0000 (UTC), Christopher Tidy
wrote:

But what about a car? Is the 130 hp or whatever maximum engine power the
manufacturer quotes a continuous or an intermittent rating?

Continuous, but at a constant rpm which is unrealistic for anything
except motorway cruising. It's done by measuring on a dyno, either an
engine dyno or a rolling road.

It's usually quoted at some ridiculous rpm limit too, fairly close to
the redline. Long stroke engines with small valves will have failry
flat curves (i.e. torque is approximately constant with speed), highly
tuned engines (motorbikes) have "peaky" torque curves, so max power only
happens when you rev hard.

But most cars are driven with insufficient use of the gearbox. Whereas on a
bike the gearbox is a natural extension of the driving style. So the engine
types work for their intended uses.


Mark Rand
RTFM