Hi,

I've ordered a "Texas Instrument MSP430 USB Stick Development Tool" that comes with a 16-bit, ucontroller. My plan is to implement hypermiler rules as inputs to the cruise control. I know where the Prius cruise control and other signals run. What I don't know is how the HCH signals and controls operate the vehicle.

How does the HCH cruise control work? Are the operator cruise control signals passed via mechanical, mult-conductor ON-OFF or like the Prius, switching of a resistor network to a control computer? For example, the Prius supports single, pulses from the resistor network to make 1 mph changes.

How is the HCH cruise control turned on-off-suspend? In the Prius, ON and OFF are handled via switching in resistance values to a single ECU input. Suspend is handled by the OR of 'brake', a stalk resistance value, or speeds below 23 mph.

Is there a good HCH control chart that shows how the HCH systems tie together? I've got some in my Prius maintenance manuals but obviously no source for the HCH equivalent. Heck, is there a recommended maintenance guide for the HCH that would show the systems?

The reason I ask is I plan to be fairly open in my ucontroller implimentation. It might be fun to see to what extent this approach could work with the HCH (or other) non-Prius hybrids. Yes, we have a Toyota Echo, a non-gas car, and it is a candidate too but not high on my list. Unlike CNW Marketing, we haven't been driving our Echo very often after we got our hybrid.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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The Honda CC also supports pulsed increments/decrements. I have not done any further investigation, but I would head over to driveaccord.com or temple of vtec to ask specifics, and especially for recommendations about which tech manuals are appropriate.

Since I don't have a Honda hybrid to test with, I was wondering if there was a Honda owner with a mechanical/engineering bend who was interested in sharing information and colaborating on automating their cruise control system. If so, we can design the interface and write the software for the uController with a well defined set of I/O routines that can be modified to deal with the Honda CC as well as the well defined Prius CC interface.

The NHW11 Prius uses switches on a resistor network so I know how to make the uController 'ghost' the CC inputs. But I still have no clue as to how the Honda driver's CC inputs are communicated to the CC controller. Also, we'd need some sort of "load" signal to let the uController know when to 'slack off'.

I guess what I'm askin' is if there is a Honda owner/operator who has the interest and skills to collaborate on a 'smart' CC uController. If so, I'd be happy to share what I'm doing if they will identify and define the equivalent Honda interfaces. This can lead to a somewhat common 'smart' CC uController. At least smart enough that unsophisticated drivers can achieve hypermiler mileage.

Although I know there are non-hybrid dirvers who would be interested in this approach, I'm really interested in seeing what can be done with our Honda, Toyota or other hybrids first. If we can get a smart CC uController working with them, then it will be a proven design that non-hybrid owners can pickup and use.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.