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.