For the one or three of you who are interested, I've made some final design progress. The control circuit is actually a 2-part failsafe circuit, and got a bit complicated. In a nutshell.......
ENABLE CIRCUIT: Draws from 12v ACC power (only when the key is in ACC or IGN), through a MANUAL switch marked 'enable', energizes the 12v enable relay, which sends 12v through a pressure switch that conducts between 30 and 40 PSI, which will run my air pump. A green LED will illuminate if the ENABLE switch is made, and an orange LED will illuminate only when the air pump is running to pressurize the water tank.
In ENABLE mode, no water is being delivered to the intake. The only thing this circuit does is pressurize the tank, and wait for the RUN circuit to demand water.
RUN CIRCUIT: Draws 12v ACC power, through a limit switch that does NOT conduct when the transaxle is in park, through the NO contacts of the enable relay, and through the manual RUN switch, engaging the 12v Solonoid valve which allows water to run to the intake. A red LED will illuminate if the */V is open and delivering water.
In RUN mode, the car must be on, NOT in park, ENABLE mode must be active, and RUN must be selected to deliver water, so that water cannot be delivered to a non-running engine.
In the cockpit, there will only be 2 switches, (enable and run), 3 led'* for system status, and a limit switch under the shift console. In the trunk, there will be a relay, a valve, and a pressure switch (oh, and a water tank!). Under the hood, there will only be a 35psi fogger (water mister) mounted to the */C plenum. The water tank will have a sight glass for determining water level, the air inlet and water fill will be in the top, the water outlet in the bottom.
I have all the parts and am assembling.......stay tuned for BOOM
Hey, isn't RICE commonly cooked in WATER?