fooling MAP sensor

[Artsi]

I would need to attempt converting so called 2bar MAP into 3bar version (absolute pressure).
I have played with idea of making a very small expansion chamber between MAP and monitored pressure outlet. Path leading into this chamber would be of certain size, and a controlled bleed orifice would decrease pressure inside chamber. MAP would be measuring chamber pressure.

Would it be a fair assumption that path cross sectional area leading into chamber would need to be twice of bleed orifice cross section, in order to be sufficient to make 50% drop in MAP monitoring pressure?

 

[Warpspeed]

It should work in theory for measuring static pressure, but it may have problems with reduced speed of response.

Any built in volume in the system will take a finite time to fill or empty before a new pressure equilibrium is fully established. If volumes were kept small and the airflow through both orifices fairly high it may be o/k, but then would a significant air leak be acceptable ?

 

[Artsi]

Some leakage is acceptable, (approx. through orifice of less than 1mm / 0,040" in diameter).
Thank's for comment. Now it's time to experiment.

 

[patprimmer]

You could put a needle valve in the second orifice to help with experiments.

The time delay could be long enough to cause a temporary lean off that could lead to significant engine damage.

Regards

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[patdaly]

Why not just put in a 3 bar?
I guess I dont see it as being as much trouble as trying to make a bleed chamber.

 

[Artsi]

It's a diesel, so it won't be a problem if MAP is lagging behind a little.

I don't feel comfortable admitting this, but 3bar MAP would be operating on the very limit of it's range in my application. This is why extravagant modding method is sought after feature.

Fellow diesel enthusiasta have gone beyond that charge pressure level, but they're operating on purely mechanical stuff. no MAP's.
I have electronically controlled engine management. I need to fool sensors in order to follow in their footsteps.

 

[Warpspeed]

A MAP sensor is just a fancy name for a common industrial pressure transducer. Why not search out a 50psi or 100psi range pressure transducer? These are available with 0-5 volt output, calibrated for either gauge or absolute pressure.

Something like this perhaps ?

http://www.honeywell-sensor.com.cn/prodinfo/sensym_signal_pressure/datasheet/ASDX.pdf

 

[Artsi]

Wow!

Thank's man!