When I finish digesting what you said I think I'm going to be impressed!!
Da!!

Jim
RV8
Pa28-180(for sale)

Sorry Jim. PWM stands for Pulse Width Modulation and it is a technique of
controlling the speed of DC electric motors (and hence the pump pressure).
Unlike lowering the voltage the torque remains high.

Short pulses with long off time mean the motor runs slowly. Longer pulses
with short off time mean the motor runs faster. These pulses are not noticed
because they come many per second.

___|-|_____|-|_____   Slow

_|---|___|---|_____   Fast


Most car manufacturers don't use this technique yet. They run the pump flat
out on what ever voltage the electrical system is putting out. They then use
a pressure regulator on the end of the fuel rail to maintain
the pressure fed to the fuel injectors constant. Excess fuel is fed
back to the fuel tank with a second line. Unfortunately this has the
unwanted side effect of heating the fuel.  Here is a schematic of the
stock Mazda fuel system.

Paul Lamar
 
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