Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





Toyota Prius

1206207209211212230

Comments

  • peraltaperalta Posts: 94
    The PSD is similar to an axle differential but with uneven split (ex 1/3:2/3) instead of the equal 50:50 split.
  • toyolla2toyolla2 Posts: 158
    Hi Peralta,
    you're close, but like most of us there is always the one piece of the puzzle missing. The short answer is that the Prius relies on the gearing equation to be true : -
    MG1 = ICE x 3.6 - MG2 x 2.6
    If you put MG2 on the rear axle then theoretically this should work if the road is dry and traction is good. The problem comes when wet and icy weather causes severe rear wheel slippage. Then the output of the front wheels will drop significantly because if MG1 is no longer able to send appreciable power MG2, then the mechanical power from the PSD will drop in exact ratio on the front wheels. This will cause the vehicle to slow down even if the front wheels had had good traction at the time. And the rear wheels will still be spinning. Take the power off those wheels and the PSD will feed even less to the front wheels in a vicious circle that could end with the vehicle moving very slowly and its back wheels spinning a few mph faster than the front and unable to gain traction.

    Clearly using the strip of road between the front and rear tires as a 'coupler' is not a great idea after all.

    When you put : -
    " The 1/3 torque is routed to a generator (MG-1), mainly for generation of traction current. The current goes to MG-2 or battery storage."

    The 1/3 torque must be routed to a generator of which the electric power must be absorbed by MG2.
    At max torque MG1 produces 100 amps which is way too rich for the battery which will only accept 50 amps worth and then for a very limited time (orders of a few minutes). When the battery is charged the system is depending on MG2 to absorb all that MG1 can throw at it. Clearly the ability of an MG2 on the rear wheel axle that could drop load by skidding off into hyper space speeds would be a no no.
    I hope this helps.
    T2
  • peraltaperalta Posts: 94
    "Clearly using the strip of road between the front and rear tires as a 'coupler' is not a great idea after all. "

    I don't see that as a problem since toyota aready has the hardware for that, the VCM. It will be programmed similar to the priciple of MB 4matic, clipping any of the four spinning tires.
  • toyolla2toyolla2 Posts: 158
    Peralta, I'm not familiar with the MB 4matic but I did consider the case of clipping power from the rear wheels (which would be attempted by shutting down MG2's controller) similar to that case you just mentioned.
    I wrote :-

    "Take some power off those wheels and the PSD will feed even less to the front wheels in a vicious circle that could end with the vehicle moving very slowly and its back wheels spinning a few mph faster than the front and unable to gain traction."

    May I delicately suggest what I think you may not be understanding about the Prius. The mechanical direct-thru' power, that you want for the front wheels of your proposed drive system, comes as long as power can be expended from MG1 in its generating role. If MG1 can't do its first job of power generation because MG2 is skidding its wheels on sheet ice (let's say) and won't absorb the 30kw of electrical power that MG1 needs to generate, then there ain't going to be no direct-thru' power for the front wheels either. And in that the Prius system is intransigent and adamante. Hence in the Lexus RX400h they leave MG2 where it is and created MG3 for the rear wheels. When they did that they retained a captive load in MG2 which they absolutely need as I have tried to explain above. MG3 - which was mentioned by a knowledgeable poster previously - now becomes an add-on with its own electronic inverter able to fully control the rear end without affecting significantly the torque being supplied to the front end.
    Peralta, I think this should fix things for you otherwise I give up. In passing I would like to say keep on with that day dreaming. I do a lot of that myself. I say it is a necessary activity to advance you beyond the status quo. It's also my standard answer to the question "Are you sleeping over there ?"
    T2
  • peraltaperalta Posts: 94
    The MB 4matic uses a center differential with 40/60 split front to rear. All differentials are open front, rear and center.

    As you said, this kind of set up is a no-no and I had the same thought before since any one of the 4 wheels that will be on a slippery surface will drain all the power there, leaving the rest of non-spinning wheels helpless.

    I was also doubtful of MB approach of 4 ETS, clipping any of the spinning wheels since this involve continuous computer operation and possibility of brakes overheating.

    Well, the result spoke for itself. It turns out that 4 ETS is very much needed at zero and near zero speed, after that it can even be turned off as demonstrated by one of MB staffs comparing ETS on and ETS off in a slippery road course. The ETS off gave a faster time.

    My AWD suggestion will have similarity to 4matic with the PSD acting as center differential, the front gets 72% of torque split. The remaining 28% goes to MG1 where it is then absorbed by MG2 to the rear.

    Any one of the wheels that spins can drain the power there just like the 4matic but 4ets took care of it.

    Peace.
  • peraltaperalta Posts: 94
    Continuation.

    As with the 4matic ETS, drive power is maintained (not reduced or cut off) and the spinning wheels are braked so that power can be redistributed to the non spinning wheels.

    Peace

    Other people invited to chip in.

    Inviting larsb to chip in.

    Host, can we tranfer a copy of these messages to hybrid engineering course discussion.
  • carquerycarquery Posts: 35
    Hi,
    I'm about to retire the family SUV and am considering something smaller that gets better mileage for my sub-40mph city drive lifestyle (Mazda 5, Prius are the top choices right now), but am wondering about the trunk space. I'm about to set up test drives, but would love to know if anyone has some real world experience out there. I've got 2 kids in the back, and need to tote around the folding stroller and have room for the "emergency kid kit" (back up outfit, diaper kit...) and then the several bags of groceries from the weekly shopping trip. Is this realistic with the Prius' trunk space? Thanks!
  • kdhspyderkdhspyder Posts: 7,160
    depending on the sized of the stroller collapsed, I'd say you'd have some room to spare.

    Kid kit, umbrellas, 4 bags of groceries, first aid kit, roadside emergency kit, galoshes, and still nooks to store things. You will be amazed.
  • pathstar1pathstar1 Posts: 1,015
    I just checked out the Pius on Saturday. Looks like, at least here in Edmonton, they are no longer "order one and wait". They have them in stock on the lot. I really like the look of the car. On the outside it's a small car (Corolla size), but inside it is amazing! I was shocked by all the rear seat leg room. Lots of storage space as well - very efficient use of space! Even if it wasn't a hybrid, I'd consider buying it just for the efficiency of the design. When you go to look at one check out the storage tray under the rear hatch carpet. You lift the tray out to get at the spare tire. Nice. Notice also the aluminum hood. The rear seats fold flat with the hatch area. All very impressive.

    I then compared it to a Honda V6 Accord hybrid. Rather funny, that. If you buy a Honda V6 Accord manual transmission you will beat the mileage of the V6 Accord hybrid, by quite a bit. Ditto for the Hybrid Civic.

    My conclusion is the only real fuel saving hybrid is the Prius, even if the bean counters say you will not realize overall savings due to the higher purchase cost. Now I just have to arrange my finances to purchace one (and sell the vehicle it's going to replace).
  • kneisl1kneisl1 Posts: 1,689
    I have heard that Toyota sells the Prius for less than it costs to make. Is this true? If so, does anyone have any figures as to what costs Toyota actually incurs in the production of the Prius?
  • stevedebistevedebi LAPosts: 3,785
    "I have heard that Toyota sells the Prius for less than it costs to make. Is this true? If so, does anyone have any figures as to what costs Toyota actually incurs in the production of the Prius?"

    Toyota lost money on every first generation (1999-2003) Prius they sold. They claim they are now making money on the car.

    No one knows just how much it actually costs to produce a Prius. But the fact that they are making more and more hybrids indicates they are making some money.
  • backybacky Twin CitiesPosts: 18,695
    Toyota lost money on every first generation (1999-2003) Prius they sold.

    Untrue. The following is from an October 2003 story in Automotive Industries Magazine. The "current generation" Prius they refer to is the first generation car:

    While the rest of the automotive world is struggling to make a business case for hybrids, Toyota Motor Company is making money. According to Toyota, the last few month's worth of the current generation Prius brought in a small profit (industry insiders say about $1,100 dollars per vehicle).

    http://www.ai-online.com/Adv/Previous/show_issue.php?id=308
  • stevedebistevedebi LAPosts: 3,785
    In October 0f 2003, the current generation would be the Gen 2, not Gen 1.
  • grandtotalgrandtotal Posts: 1,207
    No way does it cost $35K to build a Prius, let alone $40K.
  • kdhspyderkdhspyder Posts: 7,160
    As noted above this is incorrect. Originally in the first year that they were out the $35000 figure was mentioned on 2000-3000 units. Last year in the US alone 105,000 were delivered plus HH and 400h for a total approaching 150,000 just for this market. Likely there was another 150K units in the rest of the world ( est ).

    Now add the TCH from Japan and KY plus production of the Prius in China plus the units licensed to Nissan and they may be approaching 500,000 units annually.
  • kneisl1kneisl1 Posts: 1,689
    Selling for $35-40k actually.
  • kdhspyderkdhspyder Posts: 7,160
    Sorry you are right from a closer reading. It said cost but in the context I guess that was to the Chinese consumer. WOW! I'll pass. ;)

    What a discussion they must be having on the boards over there comaparing a Chery to a Prius and trying to justify the extra cost.. whoowheee
  • kneisl1kneisl1 Posts: 1,689
    It seems strange to me why so much because I would have to think the safety standards would be a lot less in China.
  • backybacky Twin CitiesPosts: 18,695
    Maybe you could read the article? It is about the brand-new, not-yet-for-sale (at that time; the article would have been written in August 2003, maybe September, to make an October 2003 magazine issue) 2004 Prius. The quote makes no sense if it is applied to the 2004+ Prius. It is clear it applies to the Gen 1 Prius, pre-2004 MY.

    I have seen other statements about the profitability of the Gen 1 Prius late in its life. They were actually posted here about 3 years ago when this very same point came up, and was debunked. Urban legends die hard sometimes.
  • kneisl1kneisl1 Posts: 1,689
    The article was written 12/05 and dealt with car for sale in 2006. I dont understand anything of what you said.
  • backybacky Twin CitiesPosts: 18,695
    We have a couple of threads going here and are discussing two different articles. It helps to use the "Reply" button so we know which thread you are replying to.
  • stevedebistevedebi LAPosts: 3,785
    "Maybe you could read the article? It is about the brand-new, not-yet-for-sale (at that time; the article would have been written in August 2003, maybe September, to make an October 2003 magazine issue) 2004 Prius. The quote makes no sense if it is applied to the 2004+ Prius. It is clear it applies to the Gen 1 Prius, pre-2004 MY.

    I have seen other statements about the profitability of the Gen 1 Prius late in its life. They were actually posted here about 3 years ago when this very same point came up, and was debunked. Urban legends die hard sometimes."

    Maybe you should re-read the article; I read it in 2003.

    I remember the debate about profitability of the Gen1, and I remember that I disagreed that it made money for Toyota. The Gen 1 was heavily subsidized when it was introduced, and I doubt it ever made money.

    However I will grant that Toyota claimed it made money at the end. I just don't believe them. For one thing, I doubt that Toyota ever recouped the investment costs (even up to the current date). So the question is how do you define making money...

    The Gen 2, on the other hand, should have made Totyota some money. I have not seen Toyota number to prove this theory. But as I said before, they wouldn't have expanded hybrids if it was losing that much $$.

    So I think my answer to correct; the Gen 1 was not a profitable vehicle for Toyota. OK, let's accept Toyota's claim of end-of-gen1 sales. How many months did it lose $$ as opposed to those few months it made 1100 per vehicle? Add that to the investment costs and it was a major money loser.
  • kdhspyderkdhspyder Posts: 7,160
    Since the Prius was the precursor it might be right to amortize all the costs onto it or more likely to amortize them over all the HSD vehicles during the first 10 yrs. It's essentially the same technology just more sophisticated.

    Gen1 Prius, Gen2 Prius, 400h/HH, Estima van, Crown/Camry hybrid, Others??

    If development and R&D was $100 Million (?) $300 Million (?) the amortization over 500,000 vehicles by the end of this year ( yr 10 ) would be $200/ veh and $600/ veh respectively.

    Now is the variable cost to make these hybrids significantly higher than a standard ICE? On that I have no clue only guesses.
    Less cost:
    No traditional transmission

    More cost:
    Battery pack
    MG1 + MG2
    PSD
    Hybrid Warranty

    I agree with you steve that the Gen1's ( future unknown ) were likely loss leaders. Now I'd be surprised if every hybrid vehicle didn't return a close to normal profit/return.
  • backybacky Twin CitiesPosts: 18,695
    So the question is how do you define making money...

    There are well-defined GAAP policies to cover that, which Toyota and any other company must follow or risk getting in major trouble.

    Toyota invested for the future with the first-gen Prius. The fact that they were making money on those cars before the end of that generation is quite an achievement I think.
  • stevedebistevedebi LAPosts: 3,785
    "There are well-defined GAAP policies to cover that, which Toyota and any other company must follow or risk getting in major trouble."

    GAAP deals with how a company reports or accounts for their money. I don't doubt that the R&D was listed separately from the production costs of the Gen 1.
  • kneisl1kneisl1 Posts: 1,689
    In addition to the plug in option, I understand Prius will come with the following scooter to extend range:

    http://www.electric-scooters-galore.com/2000x.html
  • explorerx4explorerx4 Central CTPosts: 9,621
    i know it has electric assist, but someone told me it is total drive-by-wire(no physical connection). i think it just electric assist. anyone know for sure? tia.
  • jrct9454jrct9454 Posts: 2,363
    It's an electrical assist. With the engine off and no electrical connections at all [everything shut down], you can turn the steering wheel and the wheels will move through their full range - it's a conventional linkage with an electrical [rather than hydraulic] assist. Not particularly ususual these days, actually...
  • explorerx4explorerx4 Central CTPosts: 9,621
    thanks for the reply. our '96 taurus sho had the same thing.
Sign In or Register to comment.