Page 2 of 23 FirstFirst 123456789101112 ... LastLast
Results 11 to 20 of 223

Thread: Beginning of an Automatic Climate Control System, all juiced up on Fusion

  1. #11
    inh
    inh is offline
    Maximum Bitrate
    Join Date
    Jan 2007
    Location
    Fort Riley KS
    Posts
    515
    Seems like this is getting quite complicated with your feedback system...

    Why do you want/need one? I plan on just telling the HVAC system what to do, and then if its broken and doesnt do it, well I'll notice it pretty quickly, and can fix it. All these feedback circuits and what not.. just seems a bit much.
    cashtexts - Earn money for receiving text messaged offers
    cashtexts review not a scam
    Space Navigator - 6 Axis input device: Take it apart - Driver App
    RRCam - Video/webcam capture, text overlay, and recording: 2.0 Stable

  2. #12
    FLAC
    Join Date
    Oct 2006
    Location
    Las Vegas
    Posts
    1,286
    It'll be worth it
    Simplicity has it's price. Besides there's only 2 feedback circuits, and for automatic control one of them is a must. And, when driving an analog output, it's kind of nice to see where you're at.
    Complicated....The intermediate processing between the buttons and the outputs, and automatic control, and the error checking all put what I have shown already to shame... Already, and I've barely started on all of that.
    Hopefully, what I do can be used, with little modification by others, so it doesn't remain too complicated. I'm going to include it with the Modernity skin.

  3. #13
    inh
    inh is offline
    Maximum Bitrate
    Join Date
    Jan 2007
    Location
    Fort Riley KS
    Posts
    515
    I figured control of the heat mixer, fan speed, and vent selection, internal temp sensor, and external temp sensor, with a bit of code to tie it all together would be plenty..

    Whats the sunload sensor for?
    cashtexts - Earn money for receiving text messaged offers
    cashtexts review not a scam
    Space Navigator - 6 Axis input device: Take it apart - Driver App
    RRCam - Video/webcam capture, text overlay, and recording: 2.0 Stable

  4. #14
    FLAC
    Join Date
    Oct 2006
    Location
    Las Vegas
    Posts
    1,286
    As the light shining upon the sensor gets brighter, the sensor conductance increases. The sensor signal decreases as the conductance increases. The sensor operates within an intensity range between completely dark and bright. The sensor signal varies between zero-Max volts.

    The sunload sensor provides the HVAC control module a measurement of the amount of light shining on the vehicle. Bright, or high intensity, light causes the vehicles inside temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle. If the HVAC control module detects a malfunctioning sensor, then the control module software will use a defaulted sunload value.

  5. #15
    inh
    inh is offline
    Maximum Bitrate
    Join Date
    Jan 2007
    Location
    Fort Riley KS
    Posts
    515
    Why not skip that and use a temp sensor mounted inside the car to detect the temperature inside? Instead of extrapolating it based on how much sun is shining...
    cashtexts - Earn money for receiving text messaged offers
    cashtexts review not a scam
    Space Navigator - 6 Axis input device: Take it apart - Driver App
    RRCam - Video/webcam capture, text overlay, and recording: 2.0 Stable

  6. #16
    FLAC
    Join Date
    Oct 2006
    Location
    Las Vegas
    Posts
    1,286
    I am using interior,exterior, air outlet(2) Temperature as well. Sunload isn't for extrapolating, as much as it is for anticipating, and making percieved temperature be the temperature that is really being controlled. It's how OEM systems do the job.

    Here's a quote from another thread I posted shortly after getting back into this that kind of describes what I'm talking about:
    Quote Originally Posted by h3rk View Post
    Ok as promised, here’s some things I came up with on my first day reunited with my notes in almost 2 months, I’d like to see all of these things be accounted for….chop,chop.

    Automatic control brings to the table some interesting challenges, people are going to expect to be able to set a number, representing a desired cabin temperature, and have the climate control sustem do whatever it takes to achieve and maintain it:

    First, it can be all but guaranteed that linear control of the blend damper will not provide linear control of the the cabin air temperature.

    Second, perceived cabin air temp will not always (or often) feel like actual, as sensed by its designated sensor. When the sun is out, it will frequently feel much warmer. Ambient temperature will change the perceived temperature as well. The effects of these factors on perceived temperature are not insignificant, and must be accounted for. So there needs to be a curve, or a map for the error signal driving the blend damper and fan that takes sensed cabin air temperature and corrects it with sunload and ambient temperature. More on this in a paragraph or two.

    Due to high heat transfer rates from the vehicle in moderate to very low temperature, fan speed should be increased in addition to the driving signal above solely due to outside ambient air temperature. The same is true for periods of high sunload and high ambient air temperature.

    All of these factors must be weighted and the amount by which they are weighted will vary greatly based on the different models of climate control systems (air box/ damper geometry, fan curves, etc.), and models of vehicles.

    Now, in addition to the above, one final factor should be added, or multiplied to this error signal before it drives the blend door actuator. That is a factor representing the non-linearity of the dampers effect, through the fans airstream, on cabin temperature.
    Where do we get these factors from? Auto manufacturers have the luxury of all their testing, using the automobile itself, the airbox, special wind measurements, heat transfer data, and years of experience. We obviously don’t.

    My first idea paralleled this however; come up with a simplified, general way of determining ft3 and glass ft2 fan efficiency, etc. and way to gather this data in a software wizard. There were some holes I couldn’t fill with this method in my mental walkthrough of the occasion.

    Empirical Data:
    In my years of experience in industry, I’ve found that my theoretical knowledge can not usually compete with more experience and empirical data. With this thought in mind, I turned to the idea of a calibration sequence that uses the things it knows (temperatures) and finding things it doesn’t know (factors). With some assumptions and generic models, I think that can really complete the equation for most applications.

    And since I’ve touched on extreme temperatures, I should also say that many behicles have an evaporator (anti-frost) thermostat which interrupts power to the compressor when close to freezing temperatures exist there. Refrigeration pressure switches, as with manual systems, are obviously required still.

    To round out compressor shut offs, the compressor should shut off when temp gets too high, or on full acceleration. (which brings to mind another dilemma in determining which functions like these or parts thereof are performed by each vehicles engine controller and which are performed by the climate controller. Where is the line drawn?)

    Regarding compressor shutoffs: Sure these switches can be wired in series with the compressor, but:
    When we install these new controllers, we become the only qualified technicians for them. This introduces the concept of error codes to this application. We’re not going to send them to the diagnostics port anymore, like current automotive auto climate controllers do, but there’s no reason we shouldn’t have them available. Hell, we’re taking the diagnostic information already there, and putting that on the carPC anyway.

    A few more quickies:

    How are we going to get this thing to tell the ECU to make the engine idle faster when the AC compressor clutch energizes?

    High end systems will also redistribute air based on cooler (face) hotter (floor) More than 4 fan speeds are needed for that smooth ramp up and down, a must for precise control anyway.

    The signals to these motors is varied, how do we account for all?

    I have more, but I'm going to try and get back in the groove of this for a little while first. Goodbye real world

  7. #17
    inh
    inh is offline
    Maximum Bitrate
    Join Date
    Jan 2007
    Location
    Fort Riley KS
    Posts
    515
    Haha nice writeup!

    It's all about perceived temp then.. got it =] I don't think I'm going to go THAT far with my setup, but, if needed, I will at a later date

    As for the A/C control.. If you interface the brain to the switch on the dash for the A/C swtich/setting, then the climate controls dont know any better and should still behave like they do from the factory.. I know for a fact that my A/C compressor will shutoff during full throttle, which is controlled by the ECU. There should be no reason to remove the ECU from the loop, nor should you have to remove whattever error catching system is in place for the error codes.

    If you make the brain press buttons and turn knobs just like a human would, the car knows no difference =]
    cashtexts - Earn money for receiving text messaged offers
    cashtexts review not a scam
    Space Navigator - 6 Axis input device: Take it apart - Driver App
    RRCam - Video/webcam capture, text overlay, and recording: 2.0 Stable

  8. #18
    FLAC
    Join Date
    Oct 2006
    Location
    Las Vegas
    Posts
    1,286
    Yeah, hopefully it works for most everyone who tries this the same as it does for me; shortly after writing that I re-learned that the HVAC modules usually send a compressor engage request to the engine controller, the Engine controller takes that and checks for 'compressor-off' conditions, the ECU is what decides when the compressor turns on.

    My plans involve throwing my manual HVAC controller on the shelf when I'm done, so I wont have the luxury of interfacing and letting OEM engineering do the thinking for me. That would probably be the easier route, hacking a functional module with the brain, but I think this will be more fun, and perhaps more universal.

  9. #19
    inh
    inh is offline
    Maximum Bitrate
    Join Date
    Jan 2007
    Location
    Fort Riley KS
    Posts
    515
    See, thats your problem right there! My car doesnt do any thinking, so I'll probably just lop the connectors off the back of my climate control ,and wire up the brain =] Though the japanese CRX's had an optional automatic climate control, but that would be too easy

    Good luck with yours, I'll definitly be paying attention!
    cashtexts - Earn money for receiving text messaged offers
    cashtexts review not a scam
    Space Navigator - 6 Axis input device: Take it apart - Driver App
    RRCam - Video/webcam capture, text overlay, and recording: 2.0 Stable

  10. #20
    FLAC
    Join Date
    Oct 2006
    Location
    Las Vegas
    Posts
    1,286
    Ok trying to make a working model now, but it's going to take me some time. I have to make all of the functions that react to the inputs an GUI, taking real world time into consideration so that things happen smoothly.
    I'm writing it as a simple software simulator,without using IO.
    I am not real good at it, so it will take a little time (I need the practice). Writing it as a simple software program will help me sort out a lot of things, and will be in a format that will be easy to translate to the skin (I hope). Here's what it looks like (on top).

Similar Threads

  1. AIMEE Climate Control POLL
    By Danceheaven in forum Software & Software Development
    Replies: 25
    Last Post: 01-14-2010, 09:38 AM
  2. Replies: 85
    Last Post: 07-09-2007, 04:44 AM
  3. Digital dash and climate control???
    By yamathegreat in forum General Hardware Discussion
    Replies: 3
    Last Post: 10-31-2005, 04:41 PM
  4. System control wire on amp
    By dudah85 in forum General Hardware Discussion
    Replies: 3
    Last Post: 09-13-2001, 08:09 AM
  5. Replies: 22
    Last Post: 08-13-2001, 01:42 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •