## Design Your Own Engine Program By Bowling &
Grippo

Here is your chance to design an internal
combustion engine from a handful of numbers, using the same equations
that engine designers use. Right here, right now...
First, you will need to supply a few parameters. You need to enter in
the "Brake Mean Effective Cylinder Pressure", which is in units
of pounds per square inch. Typical values for a OEM 4-stroke engine
are 125 to 150 lbs/in^{2}, and for turbocharged engines the values range
from 180 to 250 lbs/in^{2}. You also need to enter in the peak torque
value in foot-pounds. You also select if you are designing a 2 or 4-stroke
engine, and the number of cylinders. The last thing to enter is the
ratio of connecting rod length to cylinder bore - for example a value
of 2.0 means that the connecting rod length will be twice the cylinder
bore size. A value somewhere around 0.8 to 1.2 works well.

The program will determine values for the displacement of
the engine (in cubic-inches), the cylinder bore size (inches),
connecting rod length (inches), the maximum engine RPM (this assumes
a maximum piston speed of 15 meters/sec), and the engine horsepower.
All this from a few input parameters - amazing!

Bruce A. Bowling

Al C. Grippo Bowling