MAF

[Clive Apps Techno-Logicals 416 510 0020]

> >also you are relating the VE to the size of the injectors
> >this really has nothing to do with it
> >just supplies a number that is the max VE that the FI could support
> >with these injectors
> >increasing size 17% or fuel pressure 35% would allow the same injector to
> >support 100% VE at your indicated 5300 RPM
> 
> All I was doing was calculating the VE for the particular operating
> conditions which were stated---170 gr./sec. @ 5300 RPM on a 3.8 liter  4
> stroke engine , as an example of how to do the calculation.
> 
> Of COURSE maximum injector duty cycle % will occur at maximum VE (which

not true
max duty cycle should occur at max airflow regardless of VE, torque, or HPE
because this is where the most fuel is required and effciency also comes
into the equation, + high load lean limits etc.

> occurs at maximum bmep, and at a lower engine speed, one which is fairly
> near the brake torque peak, if we are going to be truly rigorous about our
> semantics.) But the same calculation would apply had the data at that
> engine speed been given. Anyone who wanted to develop a VE vs. Rpm curve
> could do so by data logging the output from the MAF vs. RPM. Pretty simple

yes quite simple too
max VE would show up here quite readily
and should also be very close to max torque RPM

wouldn't give you absolute readings on the output numbers but would let you
know if any changes you made were in the right direction

> thing to plug into a spread sheet from there. Could tell a person a whole
> lot about cam profiles----
> 
> And YES, peak bmep DOES happen at a DIFFERENT engine speed from brake
> torque peak, because friction losses vary with engine speed also!

yes something like a sqaure or RPM law
most people didn't know this 
BMEP peak RPM is usually slightly higher in RPM than torque peak
M

Clive