Automotive HVAC Automation

My company is developing an automated HVAC system for antique cars that did not have them originally. We have developed the hardware needed from off-the-shelf components that are widely used in the automotive industry and have created several 3D printed manifolds, dampers, air distribution boxes, PWM controlled fan etc. Basically, we have all of the parts and now need to find a PLC solution to provide the level of automation we need.
We do not have any experience with the Arduino family of products, do not know which model to choose, don't know the programming interface and don't know where to begin.
We have tried various online freelance websites and received resumes that appear to be riddled with fraudulent claims that cannot be verified, people who have no idea about HVAC engineering, and do not have the experience needed to efficiently find a solution.
We hope that someone out there will have the correct background and experience with HVAC and the Arduino platform of products to help us find our way.
Please contact me if you know of someone who could advise us - at least on what hardware to use. Thanks, John

I understand what you are asking, it is not an easy task. I do not have the time to undertake any projects. There are PLC units based on the arduino that have all of the interface already done, if you chose one be sure to supply it with clean and protected power. Be cognizant that the compressor clutch draws a lot of power and has a computer destroying back EMF pulse when turned off. You might look up load dump, reverse battery, 24V jump, the older cars will be susceptible to these and the controls must survive them. Be sure to qualify each sensor and load so you know what you are working with. We tried PWM with the clutches a few years back and we successfully destroyed each and every one of them. They do not like anything but fully on or off. There may be some new developments in the past few years as I am no longer current. What part of the world are you located at, that will determine how much help is local to you. Expect this project to take about 24 - 48 months by the time prototypes etc are built and tested.

This is a good project. I know a bit of HVAC and programming. I do prefer to use STM32 than regular Arduinos for more complex project. What exactly are you looking for to control? Motors? Pumps? expansion valves? etc?

You may want to consider finding two people, primarily the one with the HVAC expertise you want. Given that specialist, it should be relatively easy to find a developer who can use an Arduino to do what he specifies.

Thanks for your thoughtful remarks. Typically, in automotive HVAC, the ECU controlling the engine is responsible for switching the clutch on the A/C compressor. Normally, this is done via a relay that isolates that load from the other devices on the system. I don't understand why you would want to control an A/C clutch using PWM. It should be either on or off. Anything in between is slippage.
Thanks again for your advice.

To my knowledge the antique cars did not have ECUs, at least the ones I am familiar with. In cars with ECU's the ECU would be able to turn the compressor off and on as a engine requirement (generally output torque) but not for cabin temperature control, that is what the climate control unit did. Where the driver for the fan varies by make and model. There are many different combinations out there and with out more specifics there is not one single accurate answer.

If you visit our website, you will see that we offer EFI upgrades for these cars. We will use the ECU to switch the A/C compressor on and off if EFI is installed. If not, then it is typically done through a relay to isolate the load from the electronics.
Thanks for your remarks,

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I have no clue as to where your web site is. All I get is "My company is developing an automated HVAC system for antique cars that did not have them originally. ". This takes me back to pre 1999 vehicles. The link takes me to G-Mail asking me to generate an account. In looking it up I get this: " the Antique Auto Club of America says "antique" cars are those that are 25 years old or older . By contrast, American Collectors Insurance says an antique car is one manufactured in 1975 or earlier. States may also have their own rules." I think we define antique cars differently

I have no need to argue with you over small details. Our website is - if you are interested in what we do.

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