CLIMatronic HVAC controls for early 928's (and maybe late too)
 

Shhh :thumbup:

Although others are working on a plug and play solution for later vehicles, I thought some may be interested in the possibilities of the little project I have going on here.

Using MSGPIO from the guys that brought you MegaSquirt and the front half of a volkswagen B5 Climatronic unit.

based on the VW system with some alterations that make sense to me.

AUTO - Automatic temperature, footwell vent and fan speed mode - Pressing the button "AUTO" overrides the following settings.
- Fan Speed becomes automatic
- Foot and Centre Vent are controlled automatically
- AC Compressor control is turned on (ECON MODE reset if active)
- Defrost vent remains open if manually set - and can be turned off by def button as a toggle

In ECON operation, only the compressor is switched off. Heating and Fan/Vent operation continues to be controlled electronically if previously on AUTO or manually if in manual mode.

DEFROST Mode I
- Fan Speed Set to 4
- Foot and Centre Vent remain at current setting
- AC Compressor control is turned on (ECON MODE reset if active)
- Defrost vent opens

DEFROST Mode II - Press and hold for > 1sec
- Fan Speed Set to 7
- Foot and Centre Vent Close
- AC Compressor control is turned on (ECON MODE reset if active)
- Defrost vent opens
- Rear Screen Heater turned on
*** MODE RESETS to DEFrost I after 20 minutes or ignition off

OFF Mode - Press and/or hold FAN Down
- Fan Speed Set to 0
- Vents remain as set
- AC Compressor turned off
- Rear Screen Heater turned off
- Heater Tap is closed

Available at all times
Manual selection of air recirculation mode
Temperature setting 18-29c with LO (max cool) and HI (max heat)
- LO and HI will set fan to 4 if in manual mode

Manual options (all will turn off AUTO)
- Manual fan speed selection OFF , 1-7
- Manual selection of air flow to instrument panel vents (if installed)
- Manual selection of air flow to footwell vents

selected settings remain stored in memory after switching the ignition off and will be recalled on subsequent re-start.
Only the functions "Air Recirculation" and "Defrost II" are erased on ignition off or after 20 minutes of use.


Heating A/C Logic:
If connected to Megasquirt and
- starting from cold - coolant temp is used to hold fan speed low until engine
warms
- Engine load and RPM used to disconnect AC Compressor clutch on acceleration



I think the build page is now complete, fingers crossed of course.

No warranty - use at your own risk - Dont Try This at Home - for offroad use only - may burn your house down and/or damage the planet etc ..........

The three modifications are -

1. Servo bypass wiring as per instructions.

2. Solenoids are now Low Side driven so either - insulate and run 12v common - or change to a more common two wire insulated unit

3. PWM fan operation provides a grounding signal capable of sinking 4A. As our fans are High Side driven - an external Pchannel Mosfet or PNP power transistor is required - I used a toyota unit and changed the NPN tranny to PNP and altered the pull down to pull up.

I've not written 2 & 3 up in the build page


Draft build information http://www.reanimotion.com/GPIO%20Hv...structions.htm

Well, tell us more. You have our interest. What price line do you antipipate? Looks like a pretty good idea. There are always room for more tha one solution to any problem. Think of what this poor world would look like otherwise.

This isn't intended to be a commercial offering, more a specific project with enough detail to allow copies to be made if desired. For someone to duplicate this setup would be in the vicinity of US$300.

Over the last couple of years several HVAC head projects have appeared on the board - some designs - one commercial project but none have been exactly what I was after.
Alan posted a pretty good list that matched my thoughts
The VW CLIMAtronic head unit is a good match for the required functions while still looking correct/factory, and the absolute bonus here is that the front half of the unit can be separeted from the VW ecu giving a working faceplate which can interface to almost anything.
The hardware (GPIO) is something we've been playing with for a while now and should be familiar to the MegaSquirt guys on the board

I don't suppose you would consider a writeup when finished to assist some of us electrically challenged individuals?

Steve,

This is an excellent project, and I will follow it with great interest. Is this setup using the vacuum pods or can it control electrical servo motors for flap control?

Cheers!
Carl
90GT project

Yes, a write-up is in the works, so replicating the system will be feasable.

As for vehicle interface, yes the vacuum pods remain in place, with direct servo control of the heat mix flap, and digital control of the blower motor and AC compressor.

Steve, that is awsome. Thanks in advance for taking the time to share.

Steve,

Do you know if the electric vacuum solenoids receive constant voltage to keep the vacuum pods open, or do the switch on and off? Thanks again for sharing your work, I think it will be very beneficial to all of us.

Cheers!
Carl

the existing solenoids are driven constantly when on/active

Update for today

Display and button interface and software is completed

Currently working on the control logic, and will be basing it on the VW system as closely as possible.

AUTO - Automatic temperature, footwell vent and fan speed mode - Pressing the button "AUTO" overrides any manually input settings.

Temperature setting 18-29c with LO (max cool) and HI (max heat)
Manual fan speed mode
Manual selection of air recirculation mode
Manual selection of air flow to instrument panel vents (if installed)
Manual selection of air flow to footwell vents
Manual selection of air flow to windshield defroster

In ECON operation, only the compressor is switched off. Heating and Fan operation continues to be controlled electronically.

selected settings remain stored in memory after switching the ignition off and will be recalled on subsequent re-start. Only the function "Air recirculation" is erased after 20 minutes.

Subscribed!. I hate how dated mine looks right now.

That looks interesting for a flush console design! Can you show a pic of the B5 faceunit held in place on a center console to get a sense of scale? Thanks for your work on this!

so are the temps limited to high and low?
are there any settings in between?

fixed above - LO-18c-29c-HI
so a normal temp range for the climate control with both a max cool and max heat manual override option


quick phone pic for BigAL

Thanks for the pic - I LIKE it! Please keep us updated with progress and how-to.