Anyone know of a way to disable the cabin air filter timer?

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by PiPLosAngeles, May 10, 2016.

  1. PiPLosAngeles

    PiPLosAngeles Member

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    Every day for the last four years the timer on the air filter drives me crazy. It insists on switching from filter to outside air after three minutes, which sucks back in all the Diesel fumes and dust I just finished filtering. I would very much like to disable the timer. I'm not afraid of cutting wires.
     
  2. mrbigh

    mrbigh Prius Absolutum Dominium

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    Are you talking about the " electrostatic air cleaner " I guess?
    No changes are available..................
     
  3. PiPLosAngeles

    PiPLosAngeles Member

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  4. gallde

    gallde Active Member

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    All the incoming air goes through the filter regardless. The button just runs the fan a few minutes at high speed with the outside air intake closed to maximize cleaning of the air already in the cabin.
     
  5. PiPLosAngeles

    PiPLosAngeles Member

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    Weird. Mine doesn't work that way. When I press that button the fan speed doesn't go to high, it goes to whatever speed the fan was on when I last turned off the car (at least I think it's that - the speed that results from pushing that button changes. Sometimes it's low, sometimes it's medium, and sometimes it's high. Sometimes pressing that button makes the A/C button also illuminate and sometimes not.).

    If the air is always going through that filter, what does pressing that button do when outside air is selected?
     
  6. macman408

    macman408 Electron Guidance Counselor

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    All air goes through the air filter, as mentioned, whether fresh or recirculated. When the selector is on the fresh air setting, it still draws something like 10-20% recirculated air (for better efficiency). When it's on the recirculate setting, it still draws 10-20% fresh air (to make sure that O2 and CO2 levels stay normal, as well as flushing out anything else accumulating in the cabin air). However, pressing the micro filtration button makes it go to 100% recirculated air, from what I understand, which is one reason why it is time-limited. It also switches to the face vents to make sure that you feel the filtered air, and to blow away whatever was annoying you. The behavior is the same whether you had it set to fresh or recirculate to begin with.

    If you're annoyed by the smell of diesel fumes, you can use recirculate, which will make it less noticeable because there is less fresh air. If you're stuck behind a particularly smelly car, you can use the filter button to reduce the smell for long enough that you should be able to get yourself stuck behind a different, less-smelly car. If you're really annoyed, you can replace the cabin air filter with a different one; they come in a variety of grades, from the thin-and-cheap to thick-and-expensive to thick-and-expensive-and-containing-activated-carbon.
     
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  7. PiPLosAngeles

    PiPLosAngeles Member

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    When driving on a busy freeway or major street, one is always driving in a stream of pollution that is particularly damaging to the lungs and heart. A one-hour commute with outside air intake doubles your exposure to ozone and particulates. If you commute for two hours a day like I do you are tripling your exposure. To combat this I always run the vents on recirculate while on busy roads or freeways, and I have installed a HEPA filter in my Prius that is powered by an inverter and it runs whenever the car is on.

    The problem I have with the filter button is the way in which the Prius behaves when the 3-minute timer expires. Often it automatically switches from recirculate back to 100% outside air, which is then drawing in the unhealthy air from outside. Worse is that there is no indicator that this has happened other than the lights on the buttons. If you are busy watching the road you can go some time without noticing that your Prius is trying to kill you. This is also a problem when running the A/C as the Prius often automatically switches from recirculate to 100% outside air all on its own without asking me.
     
  8. macman408

    macman408 Electron Guidance Counselor

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    ...so don't use the filter button? It's not terribly dissimilar from just leaving the ventilation system off the whole time you're driving. And as far as I'm aware, it will stay on recirculate if you press the button to set it there, until you press the Auto button (or maybe the filter button, too) again.

    Honestly, you're probably more likely to die fiddling with the A/C knobs if you're doing it all the time. (Hence the original question, of course. But now that you know that the air is *always* going through the filter, maybe you can just set it to recirculate and live with it? And if you're really still worried, go find the highest-quality cabin air filter you can.)
     
  9. PiPLosAngeles

    PiPLosAngeles Member

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    Of course not using a feature of the car that doesn't work the way I would like is an option, but I'd rather be able to use the feature without fighting with my car to get it to work the way I want.

    If you have the A/C on it will switch back and forth between outside air and recirculate depending on the temperature outside. As far as I know there is no way to control this behavior.

    Which is why it's such a mystery to me why Toyota designed the climate control system to behave the way it does. I can't think of world where it makes sense to give the user manual controls just to have the system override the user's input. If the ventilation system is going to do what it wants anyway, why are the buttons and knobs even there?
     
  10. bisco

    bisco cookie crumbler

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    if you stay on 100% recirc for an hour, is there enough air in the cabin?
     
  11. PiPLosAngeles

    PiPLosAngeles Member

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    An average human at rest expels 20 liters per hour of CO2. At 2g/L, that's 40g per hour. OSHA allows workers to be exposed to up to 9g per cubic meter for 8 hours a day. The interior volume of the PiP is 3.265 cubic meters, which means we can fill it with up to 29.4g of CO2 before reaching the 8 hour exposure limit for CO2. The air does start out with somewhere around 1.3g of CO2 in it, leaving 28.1g for us to work with. If we target that level, and the cabin was otherwise airtight, it would be about 45 minutes before we reached that level. Since we've only been in the car 45 minutes at that point instead of the 8 hours a person can be exposed to that level of CO2, it's safe to say we'd be fine with higher levels. Cal-OSHA allows workers to be exposed to 9 times that much CO2 for 15 minutes. If the relationship between exposure time and CO2 level is linear, we could safely remain in an airtight PiP for about three hours. If the relationship is exponential it would be a tad over two hours.
     
    #11 PiPLosAngeles, May 13, 2016
    Last edited: May 13, 2016
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  12. bisco

    bisco cookie crumbler

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    you could probably play around with the duct system, so that recirc was 100% recirc all the time.
     
  13. Okinawa

    Okinawa Senior Member

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    I live in a Chicago suburb. The air is very dirty here. My wife and I have allergies. I use the Toyota brand charcoal type cabin filter in my car. It is a little expensive but I can tell it makes a big difference.
     
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  14. bisco

    bisco cookie crumbler

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    if you're doing 100% recirc, what the point of a filter?
     
  15. Redpoint5

    Redpoint5 Senior Member

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    Walter White had a solution for pollution...

    [​IMG]
     
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