Exhaust Heat Recovery optional?

Discussion in 'Gen 3 Prius Main Forum' started by HTMLSpinnr, Apr 30, 2009.

  1. GasperG

    GasperG Senior Member

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    Any pictures of this exhaust system that is seen under the car? Would like to check if my base model (from Europe) has it.
     
  2. Sergio-PL

    Sergio-PL Member

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    I think that EU versions have this system. At least Toyota mention it in Polish manual. Maybe just go to your local dealer and ask (based on your cars VIN) of how much coolant you need to buy? :)
    I'm sure they do know. Question is whether they are going to share with you that knowledge.

    EHRS has 3 main purpouses on Prius:
    1) Faster coolant warm-up => faster initial engine warm-up => lower fuel consumption
    2) Cooling down catalyst converter => possiblity to have higher exhaust gases without destroying it
    3) User comfort feature => heat that would be lost in other way gets back to the system in winter and heats up cabin instead of using electricty => lowering winter fuel consumption (slower engine cool down, longer spans with ICE off, and most important on winter, short trips point nr 1).
     
  3. David Beale

    David Beale Senior Member

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    Hmm, that diagram appears to show the coolant flowing if the engine is running, warm or not. I would suspect this is the case, as the coolant would overheat if the flow were to stop. It's not nice to overheat the coolant! ;)
    So the valve is mechanical, operated by exhaust pressure, not temperature.
     
  4. David Beale

    David Beale Senior Member

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    If you look you should see a largish stainless steel canister with coolant hoses (heater hose size) running into it. It's right after the cat. There were pictures on this forum of it.
     
  5. Sergio-PL

    Sergio-PL Member

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    It must circulate. Other way the car cooling system would fail due to overheat ;)
    But Prius have electric water pump that varies it speed depending on cooling/heating efect needed so the coolant flow is futher optimised.
     
  6. David Beale

    David Beale Senior Member

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    The exhaust heat recovery part of the system is not the whole system. Even if you removed it and blocked the lines coolant would still flow through the engine and rad. Similar to the in-car heater circuit.
     
  7. Pollymath

    Pollymath Junior Member

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    I'm going to bring this back from the dead, mostly because in the 8 years since this thread was posted, we've learned a lot about the shortcomings of the 3rd Prius EGR system and it's blow-by issues.

    I wonder if these EHR cans get plugged up the same way the EGR system does?

    My very badly plugged up EGR Cooler Equipped 2010 Prius is now throwing codes for the catalytic converter not reaching efficiency, which means that if I've got a lot of junk in the cats, I probably also have a lot of junk in the EHR. Which might mean, along with replacing the catalytic converters, I've also got to clean out the EHR.

    Has anyone taken a look inside a high-mileage EHR system?
     
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