Relay circuit- automotive

Thread Starter

jerpois1970

Joined Aug 5, 2016
1
Hello.
im seeking some help designing a seemingly simple circuit. I’m not experienced enough with this so I’m hoping you can assist.
It is in an automotive application. 16vdc electrical system with common ground. I have a normally open ground that is closed when engine rpm rises to a chosen point and opens when it drops below. I want to use that signal to temporarily close a 16vdc normally open connection.
this will engage a solenoid to shift the car From low to high gear. (Drag racing application)
The current setup holds the 16vdc to the solenoid whenever the rpm is over the set point and the wiring and solenoid get quite warm.
(Bonus if it can also have a timed or latching function that will not allow it to ‘shift’ a second time until power is removed from the circuit)

Thanks in advance!!
 

shortbus

Joined Sep 30, 2009
7,768
this will engage a solenoid to shift the car From low to high gear. (Drag racing application)
The current setup holds the 16vdc to the solenoid whenever the rpm is over the set point and the wiring and solenoid get quite warm.
Too many inconsistencies for this to be a real thing. If your car has 16VDC on it you have a problem. If you have a "drag race car" that the solenoid gets hot, you have a really slow car. If you are shifting from low to high, you're either using a Powerglide transmission or don't know how to drive.

But if this is real, look at something called a "one shot" for your bonus answer.
 
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