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How do Hybrids work? Newbie questions encouraged!



  • falcononefalconone Posts: 1,726
    I acutally can't imagine Einstein driving anything else other than a Prius. He wouldn't have any payments because Toyota would have given it to him for being the spokesperson. Hybrids... gotta love them!!!
  • acutally can't imagine Einstein driving anything else other than a Prius. He wouldn't have any payments because Toyota would have given it to him for being the spokesperson.

    That's the only way it would be cheap to operate a hybrid.
  • PFFlyer@EdmundsPFFlyer@Edmunds Pennsylvania Furnace, PAPosts: 5,808
    And this discussion of Einstein has WHAT to do with how hybrids work? :confuse:

    Let's contain the pros and cons of hybrids to appropriate topics please. Can't have it bleed into every topic.


    Moderator - Hatchbacks & Hybrid Vehicles

  • falcononefalconone Posts: 1,726
    So far my sister has told me that her Prius has been the cheapest most reliable car to date. So does CR. :P :P
  • Really.
    What were her other cars?
  • falcononefalconone Posts: 1,726
    Her prior cars were a 1999 Acura TL (good until the transmission died). Other one was a 1984 Toyota Supra my mom gave her. Started acted up last year with electrical issues. The TL had transmission problems, BUT Acura was nice and fixed it out of warranty for free. Now she has a Prius and her husband and her share a new Rav 4 (05).
  • otis1otis1 Posts: 142
    Hopefully this won't turn into a discussion about Einstein- so I'll keep my question as specific as possible.

    in reading a lot of these forums, there's a notion out there that the more you run on electric-only mode, the better your overall FE will be. (in the HH forum, seems like that has been discussed lately) So for the sake of this discussion, let's just talk about toyota systems.

    The way I understand hybrids to work (please correct me if I'm wrong) is that a gas engine is inneficient at low speeds. whereas an electric motor has an even torque band across the range of rpms. so hybrids use the electric motor to accelerate from a standstill and uses gas once the car is just cruising to maximize efficiency. So it would make sense to charge the battery while the car is "cruising" along when the ICE is running most efficiently.

    OK so here's my problem understanding why forcing the car to run at electic is good. why would you run the car at cruising speed in electric mode, when the gas engine is already at its most efficient "zone?" By depleting the battery, you are going to have to force the engine to charge it up at a later time perhaps when the engine is not runnig efficiently. as someone has already pointed out, transfering power from one source to another is not 100% efficient. (and let's ignore regen braking for the moment because the recomended fuel savings techniques tell you to anticipate stops and to minimize brake use.)

    wouldn't it make sense to selectively force the engine into running on electric-only. let's say you knew there was a down hill coming a mile after the red light so that you deplete the battery by running electric only, and you recharge it as you go down the big hill. But if you knew there was a big up hill coming, you might want to get that battery charging so that you could use the electric assist to climb up the hill.

    I know the computer in the car is programmed to seemlessly optimize when to charge and when to run on electric. But the computer cant sense the traffic ahead, the slope of the road, whether you're getting on/off the highway... etc.

    So ultimately is my thinking correct? Is the notion of arbitrarily trying to run in electric only mode a good one, or should we try to be more selective in when we try to force the car in electric mode?
  • toyolla2toyolla2 Posts: 158
    Hi Otis,
    You wrote "Hopefully this won't turn into a discussion about Einstein" I second that !!

    Here's maybe what you are missing in your knowhow.
    Internal combustion engines typically have a maxx efficiency point around a 38% power loading.
    Lower power loadings are less efficient because fixed losses predominate. Higher loadings are less efficient because losses proportional to engine speed predominate. A 38% power loading is still too high for just plain cruising at any speed below 65mph.

    -- Others may wish to know what good this is well....

    Prius hypermilers who want to travel efficiently below a steady 42mph can use a pulse and glide technique. They slowly come up to within 42mph in electric mode so the ICE won't have an excuse to start and gradually deplete the battery.
    This is the glide part of course. Then at around 20% state of charge (SOC) the engine will fire up automatically. The ICE now has two jobs, provide motive power and charge the battery. If the battery is warm it will have full capacity and charge in a few minutes to 90%. This double loading operates the ICE at its most optimum power for a short period which is known as the pulse. The driver monitors the display to know when 90% SOC is reached and will then momentarily slow to encourage the ICE to stop. Then 'feathers' the speed back up to within 42 mph under electric power only to begin the whole glide process over again.
    I hope this explanation answers some questions for you and helps a bunch more who are new to Prius. Visit for more Prius stuff.

    As another poster wrote " I can try explain it for you, but I cannot understand it for you". !
  • I have a 2006 Prius and would like to know if there is a way to force the battery to fully charge. This can be useful in case you have to leave it parked at an Airport for several weeks during the winter. If I want to show off the possible MPG I can reset the gas mileage just as my friend hops in my car with a fully charged battery.

    What kind of driving can best charge the battery to 8 bars? Should I set the transmission to B instead of P? If I am at 6 bars, I cannot seem to get the battery to continue charging unless it is cold out or I am going down a long hill.

    Any help will be appreciated.

  • Two ways to do it. The information come from PriusChat and I have not try it.

    Manual Charging

    With the Ready light on and the gear in P, press the accelerator padel. ICE will start and charge the HV battery

    Automatic Fast Charging

    1. Start the car
    2. Put it in Drive
    3. Depress both the brake and gas pedal simultaneously to the floor.
    4. The car will recognise that you want to charge the battery and move into a special "fast charging" mode.
    5. This can take up to 5 minutes depending on the charge state of your battery (you can even get it up to 100% - FULL GREEN)
    6. The car will NOT overrev and will adjust the engine speed back as the battery charges.

  • "Why in the world would someone design something where the ICE power is converted into electrical power of the MG1 which is immediately converted into supply power for the MG2. Then the MG2 acts as a motor further converting power with additional energy loss. Why not use the power directly from the ICE? Double and triple conversion of energy is just not an efficient design."

    Why? Because that's the basic principle of E-CVT. Yes, that's how HSD transmission works in a nutshell. The ICE make only 82 lbs-ft torque. It does not produce enough twisting power to properly accelerate the Prius. This situation prevents the ICE from making it's maximum power since it can't rev the RPM fast enough (already too hard to twist).

    So what does it do? The Power Split Device comes to the rescue. It spins the MG1 so fast that it generates electricity. This allows ICE to make maximum (or necessary) power while MG1 steals away that energy. MG1 generating electricity and supplying it to MG2 creates massive (295 lbs-ft) torque -- equivalent of 1st gear. Now, all the power of ICE is going out to the wheel.

    E-CVT stands for electrically controlled variable transmission. How does it control electrically? Well, it depends on the speed of MG1 -- how much electricity it generates. If you stop the MG1, you loose the control and it can't be variable anymore. You might as well call it E-NCST (Electrically Not Controlled Static Transmission).

    "In my higher math, before calculus of several variables, I thought that 66 was greater than 51."

    You do not need Calculus for this, just Arithmetic and Common-sense. You are comparing 1.0 liter Insight ICE to 1.5 liter Prius ICE. Why don't you look at the Civic Hybrid 1.3 liter highway 47 mpg? Which is greater? 51 or 47?

    By looking at the results, Honda's IMA is less efficient because 1.3 liter engine is getting less mpg on the highway than Prius 1.5 liter engine. Prius is even bigger than Civic.

    "Why is the highway mileage of the Prius less than the City mileage while the Insight is higher?"

    Because Insight simply sux in the City, even though there is less air drag in low speed city driving. Prius is equally good in both City and Highway. The reason Highway mpg is lower is due to air resistance at high speed.

    PS: I know I am replying to a very old post because no one actually addressed it.

  • midnightcowboymidnightcowboy Posts: 1,978
    LOL- how to justify energy conversion losses. You should become a politician :)
  • Less energy loss than traditional and IMA implementation. Just look at the results.
  • melskimelski Posts: 3
    I am looking into buying a HH. I currently have a 4Runner and a preschooler with alot of stuff. Can you tell me anything about the car. How it drives, stops (I read about the breaking problem), anything you feel could be helpful to me. Also if anyone knows of a better car. I want a Hybrid for the green factor and to hopefully save a few pennies. I would like to hear from people who love their car and why. I also want to know what you hate abouy it. Are the cupholders in a good place. I am still a woman and we like to know these trival things. THANK YOU all in advance for any help,ideas.
  • Kirstie@EdmundsKirstie@Edmunds Posts: 10,676
    Hi melski,
    You can get tons of feedback on this vehicle in our Toyota Highlander Hybrid discussion. Lots of current owners participate there.

    Need help navigating? - or send a private message by clicking on my name.

  • enrolbenrolb Posts: 4
    Having just recently purchased a Toyota Prius. I find it amazing that when the ICE starts it is so seamless, less noticeable than a typical automatic transmission shift! I was wondering if the ICE internals where always moving with the CVT therefore no spinup time is required?

  • toyolla2toyolla2 Posts: 158
    Hi enrolb,

    The quick answer is for speeds below 42mph you'll find the engine is fully stopped quite often. It is always fully meshed with the drive train same as an auto transmission. However the similarity ends there because there are no slipping clutches or hydraulic torque converters employed here.

    What there is is just this differential gear that the engine feeds to. A small but powerful servo feeds this differential gear system also. Power takeoff to the wheels is through a third gear. It is this gear which drives directly to the wheel axle with a 4:1 stepdown.

    If the wheels are turning and the engine is not required then the Prius computers will instruct the small servo to rotate precisely at the right speed so that the crankshaft can remain stationary.

    But how does it do it is a whole other question !
    If you want to know more, first take a look at the line dwg on Post #470 on the Toyota Camry Hybrid board. That top drawing is your car.

    See the planetary gear in the centre ? Well it's not clear from the drawing, at least not as clear as it could be, but the crankshaft of your engine is connected to the planetary carrier which supports the planet gears which race around the sun.

    The sun gear itself is driven by a hollow shaft from the smaller servo (if you can call 30kw (42Hp) small ! ) commonly referred to as MG1.

    Now here's the tricky part. In order for the crankshaft to meet the planet carrier it has to go through the hollow center of MG1 and its shaft and then proceed through to the other side of the side of the planetary assy where it can then join rigidly to the carrier.

    The third part of a planetary gearbox is the outer ring gear. This is the internal tooth gear the planets run around inside. It also connects directly to MG2, your main 67Hp traction motor. And eventually the wheels as the diagram shows.

  • I'm thinking about buying a Camry Hybrid. I'm in sales and during the summer, in between sales calls, I will sit in my car for 1/2-1hour, with the airconditioner running. My question is, will I be able to do this in the Camry Hybrid, or will it ruin the battery?
  • stevedebistevedebi LAPosts: 3,719
    "I'm thinking about buying a Camry Hybrid. I'm in sales and during the summer, in between sales calls, I will sit in my car for 1/2-1hour, with the airconditioner running. My question is, will I be able to do this in the Camry Hybrid, or will it ruin the battery?"

    No, the engine will come on to charge the battery when needed. You will use up gasoline, of course... are you sure you will have enough cargo room for your sales stuff? I actually think the Prius may be a better choice for carrying cargo.
  • Thanks so much for your quick reply :D
This discussion has been closed.