What type of valves will create this pneumatic system?

[drivefast]

I would like to use the vacuum from an engine to actuate a vacuum canister. However an engine can experience pressures of 10-20 kPa on engine deceleration, up to 101 kPa at WOT. I need to create a pneumatic circuit that will meet these criteria:

1. At 60 kPa and below the vacuum of the engine is
caped and the vacuum canister does not actuate.

2. At 80 kPa and above the vacuum of the engine is
caped and the vacuum canister does not actuate.

3. From 60 kPa to 80 kPa the vacuum canister is
activated by the engines vacuum signal.

I know how to accomplish this if I would use electromechanical solenoid valves but I don’t want the cost of sensors and microcomputers. Is there a cheap and easy way to accomplish this?

Thank you.

 

[NormPeterson]

Two valves in series?


Norm

 

[drivefast]

What type of valve. It would have to act almost like a fuse once a pressure is exceded it trips (closes) until the pressure is within spec then it resets (opens).

 

[adrag]

How about an adjustable waste gate actuator from a turbocharger? Some of them have a threaded rod that preloads the spring and allows fine tuning of the trip pressure.

 

[BrianPetersen]

Two vacuum switches in series, with different set-points, one normally open and one normally closed, and a solenoid valve. No computers no nothing.

It will probably be harder to do this without using electricity.

 

[patprimmer]

I'm with Brian.

Regards
Pat
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[workaholic0ro]

I know this is an older thread but I've just joined. I'm curious, are you trying to make a VIS ?