Evaporative Emissions Solenoid Valve

[Sprocket]

I've had a divine moment ;D and looking for some comfirmation as to whether this would work or not.

The Rover evaporative emissions purge valve is normally activated at a temperature above 70c and an engine RPM above 1500, with a MAP below 30kpa. The output is modulated on and off while it is activated. There is however no refference as to what they mean by 'modulated' in respect of duty cycle. However, having access to a diagnostic for the Rover MEMS, there is a screen that displays 'Purge Duty' and from memory it always displays 55%. There is no reference in the diagnostics as to that this 'Purge duty' means, but it would be easy to assume that it is for the purge valve?

Anyway. I have known the conditions required to operate the purge valve, but in the past only managed to set it up on one of the Misc outputs temperature pressure and rpm based, which is Ok, but certain cruse conditions might see the purge valve energised constantly. This is where I worry about the fuel tank imploding  :D

My current thinking is to still set up a Misc output for Temperature, Pressure and RPM, but feed the output into an input. Then set up Secondary PWM settings (boost alternate) and use a single line of the map to set the duty cycle against RPM for the Purge valve.

What is wrong with this? :D

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Sounds like it would work.
Great idea!

[Sprocket]

I have found some more info on the solenoid. Duty is 0 to 100% and the frequency is 16Hz. The minimum PWM period in the boost control settings is 25hz. I don't think it will be a problem.

A little more thought. The misc out will need to be fed into Anytrim, and then use anytrim to turn on and off the secondary boost control. I think this will still work as I had first thought, but will require a little more thought in the config set up ;D