[Diy_efi] RE: Throttling intake air -- references

[Dave Dahlgren]

It still sounds to me like you are regulating the input to the turbo charger,
the device we are controlling, by using the compressor output. Granted I have
seen what you are saying but suspect the reason it works that way is because the
amount of exhaust gas flow goes down so there is less energy to drive the
turbine. The only drawback i see is it makes the loop long. You change the
throttle position the engine produces less power then the exhaust gas flow and
energy goes down then the turbine slows down... Three things need to happen all
with there own delays and particular response times to come back up. Or you
regulate the exhaust flow to the turbine directly, short loop right next to the
turbine, delay time is very short response time should be very quick as long as
the bypass is sized properly. If you lengthen the loop and add more variables
doesn't it make the control scheme more complicated and prone to problems? Maybe
if the name of the controller was changed from 'waste gate' to 'turbine over
speed valve' or 'exhaust system back pressure reducing valve' or 'turbine input
modulator' it would seem less 'lossy'...  back to lurk mode..
Dave

Mike wrote:
> 
> What I was refering to was before engine *and* turbo,
> few mls of air and fuel vs lots of mls of exhaust gas.
> 
> Thing about this:-
> 
> You are driving along watching your boost gauge sit at say 8psi
> and you can reduce pedal/throttle pressure with no ill effects
> to reach say 4psi, no problems...
> 
> So clearly, the input to the engine/turbo combination is
> the uncombusted (unamplified) input,
> 
> rgds
> 
> mike


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