Horse Power and its Effectiveness

[Gary Derian]

A few comments:

For a given displacement, long stroke means small bore means less force.
This exactly balances out the longer moment arm.  Long stroke motors have a
harder time at high revs (due to both inertia and limited breathing) but
they offer no advantage in low speed torque.

Diesel engines make less torque than gas engines (naturally aspirated).
Their advantage is the BMEP is not limited by detonation so they can take
gobs of boost.

torque(ft-lb) = hp at 5252 rpm (63024 for in-lb) which is 33000/(2*pi).  A
hp is defined as 33000 in-lb per minute.

Gary Derian <gderian at oh.verio.com>

Mike wrote in part:

> Hp= torque (in-lbs)*rpm/62025  You will also notice that every single
engine
> the torque is equal to the hp at around 5150 (5168 to be exact., that is
how
snip
>That is why diesel engines make wads of torque but no hp
> because the torque is made at low rpm.
snip
> I.e. longer stroke than bore motors produce more torque than hp because
face
> velocity of piston on power stroke( vel between piston and wall) is faster
> has to go longer dist in same time (rpm)  force= mass*velocity so it will
> have more rotational force torque.