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Hybrid Vehicles Toyota Prius What to expect from the next model year Prius
311 messages, Last post on Apr 26, 2009 at 5:43 AM
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Replying to: pathstar1 (Nov 13, 2007 12:14 pm) I think it's documented and confirmed by scantool that MG2's controller will current limit to a battery bus draw of 100 Amps. The two packs should share this current since the volt drop in their internal impedances may force a current equalising effect, not perfect but close enough for new packs and in the short term. I don't want to debate whether this is a good idea for reliability going forwards, perhaps not. But right now this is a test about the human interface response to an extended driving range. MG2 will have benefit from the upconverter that normally transforms the 201v pack voltage towards 500v as the vehicle goes from 20mph to 50mph, of which you may have forgotten. So connecting packs in series is not an issue here. As the vehicle gains speed over this range the current will have to reduce inversely of course to observe the nominal 21kw limitation on battery power specified with the Gen II Prius (NHW-20). And I suppose it goes without saying that as long as 21kw exceeds the power needed to cruise, the vehicle will continue to accelerate. You've not addressed my concern of MG1 approaching 10,000rpm as the vehicle nears 60mph which may setup an audible whine. This speed was promised earlier for the Li-ion pack which is why I bring it up. Have you seen these ? The following contain useful temperature / power graphs For CY1997-2000 NHW-10 Prius, 7.2V X 40 modules (cylindrical) For CY2000-2003 NHW-11 Prius, 7.2V X 38 modules (old prismatic) (They used to have a comparison page, but it was gone.) For CY2003-2005 NHW-20 Prius, 7.2V X 28 modules (new prismatic) For CY2005 HH/RX400h, 9.6V X 30 modules (metal prismatic) T2 |
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I'll try once more ! For CY1997-2000 NHW-10 Prius, 7.2V X 40 modules (cylindrical) http://www.peve.panasonic.co.jp/catalog/e_maru.html For CY2000-2003 NHW-11 Prius, 7.2V X 38 modules (old prismatic) (They used to have a comparison page, but it was gone.) For CY2003-2005 NHW-20 Prius, 7.2V X 28 modules (new prismatic) http://www.peve.panasonic.co.jp/catalog/e_kaku.html For CY2005 HH/RX400h, 9.6V X 30 modules (metal prismatic) http://www.peve.panasonic.co.jp/catalog/e_kinnzoku.html T2 |
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Replying to: toyolla2 (Nov 12, 2007 9:43 pm) Thanks, interesting link. I'm wondering if the cost is prohibitive vs. performance for the consumer market. Businesses can depreciate costs, so their equipment can be more expensive and still be economically viable. Also, delivery vans don't generally run long distances at high speeds; I wonder how that would work out with consumer vehicles...
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Replying to: stevedebi (Nov 15, 2007 5:43 pm) Need a hybrid, but the current Prius interior and dash layout are not to my liking for the money spent. Wish they had a more standard dash layout, than I would jump on it. Though some pictures are around of a possible new hybrid Prius in 09, none of which have a interior shot. Toyota, I hope will make the follow on Prius much better inside. Still like the exterior, but that to now needs a refresh. If anyone in the know, has some rumors about what the new Prius follow on interior looks like, please post a link. Thanks |
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Those interested in what the 2009 Prius may look like, check the March issue of Motortrend. There is a drawing based on information or rumors from employees inside Toyota. The drawing shows a very sleek machine, although drawings are often exaggerated. Also mentions that the engine will be a 1.8 litre, and initially will use the current battery pack.
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Replying to: lm2 (Feb 02, 2008 1:57 pm) As a counterpoint, I love the dash on my current Prius I hope that keep that in some form or another. |
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First, if we are going to speculate let's look at some numbers. To start with, I've never fully understood why the current Prius engine runs only to 5000rpm, whereas the 2.4L in the Camry Hybrid runs at the same speed as the engine in the non-Hybrid Camry which is 6000rpm. With that in mind I would expect that before upgrading engine capacity to 1.8L, from Im2's Motor Trend reference, that Toyota would be addressing this rpm issue with the original engine first. Sure I'm not expecting them to get the full 108Hp from the Echo's 1NZ-FE engine but 20% increase from the 76Hp Atkinsonised engines, that were installed starting with the 2004 Prius, would be welcome. The following is a rehash of my #104 post of three months ago. It was in answer to wwest regarding the suggestions of more horsepower via forced induction. This unfortunate 1.8L idea being also a step in this direction. Even though I don't own one yet my test drive of the Prius told me the car is powerful enough. And incidently that's from the vantage point of someone who happens to drive a Lexus. Clearly fuel economy will suffer with a 1.8L and the last time I looked the Prius is under no threat in the horsepower race. To continue with the simple expedient of merely increasing the engine rpm by 20% must needs the rest of the system to accomodate this. And inexpensively too I might add. The fact is you have to start with the MG2 system which will need upgrading 20% also, since at lower speeds the majority of the torque at the wheels comes from this machine - 259lbs-ft versus 59lbs-ft from the ICE. To do this the three stage reducer giving a 4.113 stepdown ratio needs to be stretched still further to 5.0. This will require MG2 to run at 7200rpm at 100mph and to do that will require the upconverter to supply a max of 650volts, up from the 500volts used previously. At the same time MG1 will need to reach 12000 rpm to generate this voltage also. All these things have been done with the Camry Hybrid by the way. The remaining gearing and motor currents will stay as before. Since voltage and rpm are 'free' only the minimal cost of the two gears being changed is the salient factor. Motor windings can remain the same since the engine torque is not being upgraded. The system continues to deal with the same torque as before but at a newer maximum rpm. Let's determine the max power point using ICE = 6000rpm, MG1= 12000rpm. Then 12000 - 3.6 x 6000 = - 2.6 x MG2, so MG2 = 3692rpm and since 7200rpm = 100mph..... The current Prius engine does not reach full power until 51.28mph, and the calculation shows this suggested new arrangement won't change things either. Of course MG2 would now be rated at 60kw with somewhat higher iron losses but these would be compensated by improved cooling. This is still the same vehicle so the rolling losses haven't changed, just the time the system can be run at full power at maximum acceleration has been reduced. It must be obvious to most that the more powerful you make the car the shorter the time you are going to have to use that power if top speed, as here, is clipped at 100mph. And this is what the designers are banking on. This also means that despite the expected performance uptick anyone who puts a towbar on this vehicle can still put the system at risk. In #104 replying to wwest earlier I wrote one of the problems with HSD is the ring gear and the components connected to it. Rotating this assembly beyond 6000rpm raises a serious balance issue. It represents the output shaft of the whole system and this rpm at 100mph is fine for a planetary connected to a 4 cyl engine, later on however it may turn out to be too slow for the higher speed small engines in the pipeline It will be interesting to see whether this ring gear increase is the choice Toyota will make. Everything has risk but it's not like the greater population are regularly driving or should be driving this vehicle above 85mph anyway that would repeatedly test 7200rpm speeds on this component. Finally I would like to see them copy the Camry design which has omitted the sprocket chain power takeoff - thereby possibly releasing a 6% gain in torque by my estimation. If you care to go to #470 on the Toyota Camry Hybrid board where USBSEAWOLF2000 has posted diagrams of the two systems you can see what I mean. I am fairly sure they won't go so far as to copy that second planetary used to raise the specific power of MG2 that you will also see there. For that matter I think HSD design will stagnate until the Chevy Volt appears or Honda returns with a new hybrid but not with their mechanical CVT that can't seem to reach 100k miles nor with the IMA which becomes ineffective when the HV battery is exposed to extended sub zero temperatures. T2
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Replying to: toyolla2 (Feb 04, 2008 12:19 pm) I don't know where these rumors begin, but I suspect it's magazines trying to sell copies, not real info. leaked from Toyota. Including the image showing a sleeker Prius. Do know that the "bean shaped" (my description, please don't read any of my feelings into that term)  concept car first shown last year at the German Auto show has many design ideas that, according to Toyota, will be used in the next iteration. I concur that the current car is powerful enough. And I'm comparing to a 2001 Nissan Pathfinder LE (240 HP 265 lb-ft of torque). My Prius passes better on 2 lane highways than the Pathfinder ever did! Probably a combination of lower weight, lower wind resistance, and electric motor torque assistance.
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Replying to: pathstar1 (Feb 04, 2008 12:41 pm) That being said a 'new' model has to offer something to make the next model attractive so as not to become stale. Increased fuel economy would be wonderful if it were to jump to to mid 50's under the new EPA standards; ( 1.8 gal / 100 mi driven or 4.28 l/100km ). With EV / ECON options it would be very appealing to certain groups of buyers. As for a new engine it appears that Toyota is going to the 'R' structure across the board beginning with the 1GR in the current 4R. That's been followed by the 2GR, 3GR, 1UR, 3UR and most recently the 2ZR 1.8L in the new Corolla and Matrix. A new 2.7L I4 is forseen in the new Venza in the fall, 1AR? Would it not make sense to standardize everything to Atkinsonize the current 1ZR 1.6L for the next Prius? |
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Just wondering if there is any info leaked out about if the new 2009 model will have better seats. If it had we would have bought one. Really needs a better drivers seat fro long trips even tho it's a city car. height adjustment as well as a more comfortable seat would be welcome. Any rumors? |
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