Engine load vs RPM and torque

[Gary Derian]

Inertia forces at TDC and BDC are easily calculated with a little trig.  Gas
pressure forces can be calculated by knowing compression and temperature
rise.  Also, knowing power, BMEP can be calculated and an indicator diagram
inferred.  It is generally accepted that maximum pressure occurs at 12 deg
ATDC.

Gary Derian <gderian at oh.verio.com>



> Hi all,
>
> This is a little off charter but is still related somewhat (especially to
> those with artificial aspiration.)
>
> I'm looking for some software or code (Matlab, Working Model etc...) that
> will allow me to calculate the loads seen by the piston, rod, etc for
> various torque/speed combinations. For instance, is it better to make 100
HP
> using 15 psi of boost at 5500 rpm or 100 HP at 6500 RPM using 7 psi of
> boost...
>
> I'd like to be able to input the weights of the piston and rod, and the
> torque value to obtain their loadings. Most people will tell you the
largest
> loads are seen on the exhuast stroke at TDC, but that doesn't explain why
> those turbo Honda's start bending rods at 10 psi...
>
> I have a small single cyl that I'm going to be putting a blower on. In
it's
> current configuration, the factory tells me additional revs will seriously
> comprimise reliability. OK, but with the blower, what is the ideal speed
for
> my desired HP?
>
> Repond off list if you feel compelled. Thanks.
>
>
> Matt Beaubien
> mbeaubie at ualberta.ca
> 3 x 510
> 1 x 300ZXT