Okay, so I was thinking. My car computer should be able to tell throttle position so I was thinking maybe I could write a script that if throttle was 0 for more than 10 seconds it would shut of the engine using a relay.

Alternatively if I can find out how to read state of charge I could have it only shut down if the SoC is above 33% or so.

Anyone see a problem with this? If I do it I'll document it in my car computer thread.

 

My understanding of the 2004 HCH is that the computer has a few things it looks for before it will perform an autostop. Engine temp has to be in the normal range, there has to be adequate vacuum pressure, IMA battery levels, the mph of the car has to rise past 10 mph and then fall below it again (for the CVT), and the brake has to be depressed (for the CVT). (there may also be an angle sensor involved as well, but I haven't experienced it enough to be certain)

My idea for a forced autostop for the CVT HCH:
two switches
one momentary, the other a toggle with an annoying blinking led.

The toggle switch would be connected to the same wires as the brake light switch on the pedal, making the computer think I'm riding the brake but without putting any pressure or depleting vacuum. The annoying blinking led would remind me that it was on because my brake lamps will remain lit during this CVT forced autostop.

The momentary switch would be connected to the tach from the wheels and would serve as a momentary disconnect causing the computer to think that the car is moving slower than 10 mph for a brief moment.

By flipping the brake switch on and then hitting the tach momentary switch, I think it would satisfy the computer's requirements for an autostop.

This would seem to give me full control of the CVT HCH, the 12v would still be connected to the 144v IMA, and I'd have the ability to come out of autostop in an emergency by pressing the brake or by pressing on the gas like normal. When I'm done with the autostop, I flip the brake switch to off and it takes the car back out of autostop. The annoying blinking LED is to remind me that my brake lights are on in case I come out of autostop by other means.

Any other thoughts or parts I missed?

 

but its not just a break thing that keeps it in auto stop. There is vacume involved as well. Try this experiment: When in auto stop press down on the break as hard as you can and let up just enough to be able to press it again. You will come out of autostop even thought the break lights remain lit.

 

yes, but by not actually using the brake, you wouldn't be using any of the vacuum pressure.