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How do Hybrids work? Newbie questions encouraged!

SylviaSylvia Posts: 1,636
Have you ever wondered how hybrids work? What is the technology behind them? What is the difference between Toyota's Prius and Honda's Insight? Here is the place to ask your questions.
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Comments

  • rfruthrfruth Posts: 630
    Whats the deal with iPod and BMW ? Are they (Apple) getting into the car business http://www.apple.com/ipod/bmw/ or am I reading too much into this ?
  • SylviaSylvia Posts: 1,636
    Hi Rob - probably a question better suited to the News & Views board. This discussion is geared towards how hybrids work. Thanks!
  • SylviaSylvia Posts: 1,636
    What are the different types of hybrid cars and who is using what technology? Short list would do fine.
  • rfruthrfruth Posts: 630
    Prius & Escape = full hybrid = parallel hybrid


    Insight Civic and Accord = IMA = serial hybrid

    Silverado/Sierra = ? = starter/generator control module

  • stevedebistevedebi LAPosts: 3,786
    Insight Civic and Accord = IMA = serial hybrid

    A serial hybrid uses the engine to run the batteries, and has only electric propulsion. At least that is my understanding.

    I think the Honda IMA is a parallel system, because both the ICE and electric motors are engaged at the same time.
  • rfruthrfruth Posts: 630
    I stand by my original statement that the Insight Civic and Accord = IMA = serial hybrid
    however howstuffworks.com and Insightcentral.net http://www.insightcentral.net/encyclopedia/enhybrid.html say what you are saying and that is IMA is a parallel system, if you ask me (and others) IMA is just that integrated motor assist, it (the IMA electric motor) is in series with the gas motor, the vehicle can't move without the gas motor thus its a serial hybrid. Prius / Escape can use either or both thus a parallel hybrid.
  • stevedebistevedebi LAPosts: 3,786
    I'm not asking anyone's opinion, I'm stating facts. The words parallel and series have special meanings when it comes to hybrids. Here is the link for those who haven't seen it:

    http://auto.howstuffworks.com/hybrid-car2.htm

    "You can combine the two power sources found in a hybrid car in different ways. One way, known as a parallel hybrid, has a fuel tank, which supplies gasoline to the engine. But it also has a set of batteries that supplies power to an electric motor. Both the engine and the electric motor can turn the transmission at the same time, and the transmission then turns the wheels."

    Note that both Honda and Toyota hybrids fit this definition, though many Prius enthusiasts insist that the planetary gearset does not meet the qualification of a transmission. But it powers the wheels, so cut some slack here... the two terms refer to how the electric motors are used.

    "By contrast, in a series hybrid the gasoline engine turns a generator, and the generator can either charge the batteries or power an electric motor that drives the transmission. Thus, the gasoline engine never directly powers the vehicle."

    Emphasis is mine...

    Many Prius enthusiasts make their own definitions, based on the difference in the HSD, but that doesn't change the scientific literature. In implementation, the HSD does have the electric and ICE operating at the same time (different parts of the planetary gearset), and in the IMA the electric is in line with the transmission. This causes some confusion. I suppose that is why we have this forum...
  • stevedebistevedebi LAPosts: 3,786
    "IMA is just that integrated motor assist, it (the IMA electric motor) is in series with the gas motor, the vehicle can't move without the gas motor thus its a serial hybrid. Prius / Escape can use either or both thus a parallel hybrid. "

    Just to claify for the newbies:

    The IMA (Honda Hybrid) can move with or without the electric motor, at any speed, since the ICE is used at all times. It won't perform so well or get very good MPG though.

    The HSD (Toyota Hybrid) cannot move without the electric motor - battery power is all it uses up to about 15 MPH. At least, I've never seen any Prius enthusiasts claim it will move from a standing start with ICE only.
  • rfruthrfruth Posts: 630
    FYI do you consider howstuffworks.com scientific literature ? It doesn't really matter but I do know know the difference between a parallel and series hybrid - do note that the Prius can move without its electric motors and to say thats all it uses up to 15 MPH is just plain wrong, I don't know where you heard that but ask that source if the ICE ever runs when they are in reverse or at slow speeds (yes it does thus the parallel label, it can ((and does)) use either or both motors as needed)))
  • stevedebistevedebi LAPosts: 3,786
    "FYI do you consider howstuffworks.com scientific literature ?"

    I figured you'd probably catch that. No, not really, though I haven't ever caught them in a factual mistake (I've only checked the automotive stuff). I suppose I should have said "reliable" or "known factual" source.

    "do note that the Prius can move without its electric motors and to say thats all it uses up to 15 MPH is just plain wrong, I don't know where you heard that but ask that source if the ICE ever runs when they are in reverse or at slow speeds (yes it does thus the parallel label, it can ((and does)) use either or both motors as needed)))"

    Can you please quote me a "reliable" and "factual" source that says the Prius can start up from a standstill on ICE only? The ICE engine will engage at low speeds - to charge the batteries and power the electric motors. At least that is my understanding of the system from the Toyota web sites, which include some very nice animated graphics of the HSD system.

    It's only a side note anyway, since both IMA and HSD are not designed to work ICE only.
  • rfruthrfruth Posts: 630
    Glad you've seen the toyota.com FAQs for the Prius cause the very last one (# 25) reads Does Toyota support the modification of my Prius to be a plug-in Hybrid and run on electric only mode and the answer is NO (the ICE is sometimes used at slow speeds) but hey I'm no expert (although everything I've said I believe to be true) but you hybrid owners need to jump in here and tell us your experianes.
  • robertsmxrobertsmx Posts: 5,525
    Honda recently showcased a hybrid scooter prototype. It utilizes dual mode hybrid system (Series and Parallel, depending on situation). Here is how Honda differentiates between the two…

    “The hybrid scooter's internal combustion engine and direct rear-wheel-drive electric motor function in two distinct modes. In series mode, when riding on flat ground and when high output is not required, the engine alone powers the electric motor. In parallel mode, used during acceleration and when high output is required, the electric motor assists the engine. ”

    Based on this description, Insight and Civic Hybrid would qualify as Parallel Hybrid since IMA is an assist system. HowStuffWorks seems to describe it in a similar way.

    BTW, Honda FCX utilizes Fuel Cell Stack to help keep the ultra capacitor pack charged (no batteries in this case). This charge in the ultra capacitors is used by the electric motor to drive the vehicle.

    Technically…
    Series: One source transforms energy into a form that is utilized by another source to drive the vehicle (a “series flow”).
    Parallel: Multiple sources are used to drive the vehicle at the same time (in parallel). IMA or any assist mode hybrid would be a parallel hybrid.

    IMA also operates in series mode when necessary. Rolling down a hill, or when batteries need to be recharged, the electric motor doesn’t assist the ICE, but sends energy to recharge the battery pack.
  • john1701ajohn1701a Posts: 1,897
    > The HSD (Toyota Hybrid) cannot move without the electric motor - battery power is all it uses up to about 15 MPH.

    No offense, but that is totally incorrect.

    The limit for electric drive is 10kW.

    If you exceed 10kW, which usually happens when accelerating, the engine starts up.

    Cruising doesn't require that much electricity. So you actually can sustain speeds up to 42 MPH. And there is typically enough battery power available to do that for a mile or 2. Under ideal conditions, you can drive up to 3 miles using the battery.

    Then, it only takes about 10 minutes of driving at speeds above 42 MPH to replenish the charge-level to cruise on electricity for awhile again.

    > At least, I've never seen any Prius enthusiasts claim it will move from a standing start with ICE only.

    That's true... since HSD wasn't designed to do that. 100 percent of the time thrust is being sent to the wheels by the engine, electricity is also being generated. Remember, the A/C, steering, 2 small heaters, and many of the accessories (like the lights) require that electricity to run anyway.

    JOHN
  • stevedebistevedebi LAPosts: 3,786
    John, the quiestion was would the Prius work without a battery pack (pack totally depeleted, or whatever). That was what I was speaking of. Do you know if it will work, i.e., if the pack is totally depeleted, will the car drive without it?

    I realize, as I said before, that it is a moot point for the HSD, since it wasn't designed for that mode.
  • john1701ajohn1701a Posts: 1,897
    How exactly would you completely drain the battery-pack?

    The system has quite a few protective mechanisms preventing that from ever happening.

    JOHN
  • robertsmxrobertsmx Posts: 5,525
    Let us say a malfunction.
  • john1701ajohn1701a Posts: 1,897
    Any component in a vehicle can malfunction.

    Unless there is more than just a remote possibility of it actually ever happening, discussing it doesn't have a point.

    In other words, there is a higher statistical chance of being in an accident. So why focus on someless even less probable?

    JOHN
  • robertsmxrobertsmx Posts: 5,525
    Most people are wary of electrical systems in a hybrid, and how it interfaces with the rest of the drive train, than they are of any other system. So, it is logical to bring up that probability.

    But, my point was to bring out a scenario where electric supply fails for a moment. Would the gasoline engine be able to move Prius by itself?
  • Toyota's Hybrid Synergy Drive is the most advanced automobile technology ever created. If I recall, the Prius (and all HSD vehicles) are equipped with at least five computers on-board to make constant calculations and adjustments. For all practical purposes, Toyota's hybrids (and now Ford's, as they're using the 1st generation Toyota technology), are supercomputers on wheels.

    Now, should the "electrical system" fail, what can you expect? Your car is broken. I speculate (though certainly can't confirm) that you can't drive because the car has an eCTV (electronically-controlled continually variable transmission). This isn't something to worry about, though. We're not talking artificial intelligence here, capable of destructing the world if it gets out of control... it's still a car. You should be more worried about a flat tire.
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