Alex, clutches and two-speed transmissions probably work for WrightSpeed's business plan. If I remember more than 30 years ago Eaton Corp was working on a similar idea and abandoned it. Their team had problems getting the hydraulic actuators to work consistently. Much later Tesla tried the same thing, it failed, and Musk couldn't even get Magna onboard to build that type of system. There are easier ways to go. Tesla's problem was not difficult to solve but it was a case where the design team needed someone with a better grasp of the fundamentals. In essence they needed a motor with a larger magnetic circuit that would be capable of driving to 60 mph in four sec but with the motor turning at only 7000rpm rather than 14000 rpm. Then for those speeds exceeding 60 mph and approaching 125 mph they needed a Prius style voltage upconverter of around 100Kw. This would allow the controller to preserve the V/F ratio going forward. Acceleration would continue at constant power all the way to top speed and there would be an inverse torque drop off during this period but not as drastic as there would have been if the V/F had to suffer through the lack of an upconverter. Tesla didn't take this route, however. They chose a friendlier top gear ratio, moved 650 amp transistors up to 850 amp and did something to the motor on which there were no specific details. I think that progress is made when moving away from mechanical systems. Linamar's twin motor rear drive unit described on GCC this month is a case in point. Despite dispensing with a differential and a hollow shaft motor, the agregate power of two smaller motors could be 26% greater than one purely on considerations of surface/volume ratios alone. Thanks for the links BTW

@Alex Well, I would have to agree that a quadrature system would meet a constant power minimal torque ripple requirement. And as you imply it could be implemented with just four NPN power devices if each phase winding was center tapped. The downside of powering each half winding alternately would mean a 1/root2 derating compared to a bridge. Notwithstanding there is always that added benefit to have IMs operate to 14000 rpm. I don't understand why Honda, in the first place, would even consider a 12Kw automotive electric drive specifically within its 0-1500 rpm range. Finally their Accord Hybrid due out this year is using a 125Kw motor operating to 15,635 rpm which will probably be the same size.

Honda is designing this motor for the IMA system which is focussed on the 0-1800 rpm range mainly. It is generally accepted that it is particularly difficult to get high effcy levels at 60Hz excitation levels, consequently all this effort to do with alternative magnetic structures. It should be pointed out that the standard induction motor efficiency will rise with applied frequency perhaps exceeding 95%. A property of the induction motor that I've noted is that constant copper loss is expended per unit torque i.e. rotations from 1 rpm to 10,000 rpm will incur a constant loss while providing constant torque. It is therefore evident that effcy must therefore improve with rpms. Of course iron loss is to be expected rise with the increasing frequency of excitation in order to gain those rpms however these iron losses can be mitigated with the use of thinner stator laminations as in those 400Hz motors employed in the avation industry. This new Honda motor is application specific to the company's IMA system and is not going to be suitable as an EV traction motor, but then neither are MG1 and MG2 on the Prius for that matter. However I wouldn't be surprised if it found further use as the generator on later variants of the new 2014 Accord hybrid design.

Whoa !! Did I read that article right ? Or do my eyes deceive me ? Regardless. Combat Engine = Me Want You may have felt, as have I, that there was some automotive need not yet fulfilled - but for no longer it appears. Finally for the aggressive driver, the one ingredient we've been missing all these years - the Combat Engine - may soon be available. In your dreams Honda with your "Earth Dreams" powertrains, the Combat Engine is for me. I can see me now whizzing down the road with the C.E. on WOT. Oops did I just nod off, sorry. But then this new engine is to be a two cylinder while an earlier report had recommended that a 3-cylinder configuration was optimal for exhaust gas flow when seeking to avoid unfavorable interactions with the discharge from the adjacent cylinders. (Or was this yet another technical article I clearly didn't comprehend). But then would even a 3 cyl 3.0 litre engine be enough to propel a tank ? I sure don't know. They mention a possible hybrid spinoff application. Really ? In case someone from the project is reading this I can save you heap of dough. Hybrids happen to need constant torque engines on account of the fact that +70Kw alternators have constant field excitation due to those expensive Neodymium magnets that you may have read about. But then diesel torque characteristically drops off above 2400 rpm. This infers that the allowable current generated will have to be proportionally reduced as the engine proceeds beyond that point towards top speed. And all just to reach that final 25% of max power. Not good. I would have thought that hybrid design - particularly the two machine variety - is difficult enough already without having to make that concession. Just where is Rafael Siedl when you need him ?

I do not see any error Take another look. I was referring to the graph for the gasoline version, not the diesel.

The DOE never seems to tire of throwing money at the problem of supply side management. At least here in Ontario we have put wind turbine installations on hold but you have to wonder how these projects get ramped up so rapidly. Oh right, lobbyists ! Meanwhile there seems to be precious little interest in promoting improvements that could be immediately beneficial on the demand side instead. Sure there is Time of Day metering with its punitive rates at peak periods, but no domestic electric water heater control that could allow power operators to remotely dump these significant low priority loads as peak periods are encountered. Other low tech solutions bring into question the reason for the poor availablility of LED fixtures for residential housing. It seems that unless you are prepared to use AA batts or wall sockets there seems to be a dearth of LED powered ceiling fixtures to be found in local stores.

The first engine graph has Torque and Power designations reversed !

Electric vehicle design always involves that quick or fast tradeoff. The reduction gear ratio chosen here allows for a fast 100mph top end but results in a disappointing 10sec to 60mph accel ramp. I would say that most drivers including myself would accept a lower 80mph limit if it came with a quicker 8 second ramp. Thoughts anyone ?

When taken out of park, the gearbox enables increased torque output while allowing for lower motor input speeds, an attribute that conserves battery energy and extends range. ?????? Very confusing. How does the single speed gearbox enable greater torque, surely the job of the controller ? Unless it's meant that controller current output is limited until the parking pawl is totally removed at which point motor current is allowed to increase to its maximum. As a point of good design all controllers must have a "creep" mode to avoid the vehicle falling backwards on a hill. OTOH killing initial acceleration to conserve energy - are they nuts ? Generally you want a good launch from those lower speeds to compensate for the lack of raw horsepower the EV will encounter at higher speeds. Further benefitting the refinement, the single-speed gearbox helps maintain the correct installed axle-shaft angles of the driveline. IOW something required of any gearbox mounting on the planet.

Hmm so the differential cage is connected to the planet carrier, and of course needs the hollow motor shaft also. I visualize this concept of an electrical drive train assembly as being somewhat of a "civil engineering project" when I consider the physical size and therefore special handling to be required as it proceeds from manufacture to test. Can't help thinking that two motors each with integral planetary would be simpler to fabricate in mass production and be lighter to handle and at the same time not be such a formidable assembly for the test dept to manage. Then there is the logistics of shipping and storing of this item in quantity. Since auto plant production managers are already conditioned to accept extensive engine and transmission assemblies when they marry the body to the chassis the cost of messing around with this particular incarnation probably doesn't raise red flags in their circles.

-john McAvoy A LEAF can be leased for $249 a month today. I've owned one now for 18 months. I have never accidentally run down my battery in 20,000 of driving. I thought that Nissan was supposed to screen out customers that drive more than 1000 miles/month. Apparently not. The rate of mileage you are putting on will prematurely kill your battery. I hope you have only a 3 year lease because that battery is going to be 50% down in range capacity very soon. -Kit P making your own power is just not cost effective Not with photovoltaics it isn't, I agree. But a 2HP engine running on NG certainly is if the waste heat can be captured for space heating and if about 5Kwhr of lead-acid storage is installed to support peak electrical loads. The result is perhaps a 20% higher gas bill more than offset by the absence of an electric utility bill.{Honda FREEWATT}

This 16 cell monitor is fine if you can guarantee robust cell interconnection. However for the vibrations that are encountered in an automobile environment that could be a big if. At the AEVA site a team has embarked on a one micro per cell design in a 228 cell string using an optocoupler half duplex loop with but a single host micro which interfaces to a laptop. The pcb for each micro allows for direct mounting on to 40Ah Li-ion cell terminals which simultaneously supply 3.4V power and a monitoring point. The cell voltage charges a 1.0F supercapacitor which allows stable operation to the circuit despite 120Amp bursts during vehicle operation. The pcb also sports the necessary bypass resistors, led indicators and piezo speakers. The latter allow for both audio and visual error signalling in the absence of the laptop. The Toshiba chips look fine for applications up to 96 Volts but the approach described above originally contemplated for 750Vdc is now operational on 375Vdc.

First I have to say that this topic has attracted the more responsible responses, perhaps I haven't been visting this site as often as I should. But definitely a change. Hopefully the trolls have finally given up, but we will see. There probably is no business case for the Corvette, only that this marque can suck off the General Motors teat makes it at all possible. It is probably true that may be the case for many of the other large manufacturers producing low volume performance vehicles as well. And always spewing the "need for a flagship car" Kool Aid. I notice that even Aston Martin has trouble going it alone and is now in the process of seeking new investors. As regards GM it is one of the pitfalls of providing a taxpayer bailout that has effectively allowed this formerly distressed corporation to avoid a necessary restructuring. The corporate culture remains unchanged and therefore not deterred in its mission to cater to a small group of consumers who like to publicly demonstrate that they can burn as much fuel as they can afford - the urban atmosphere be damned. BTW I find the statement most fuel-efficient Corvette ever at a whopping 9L/10Km on the highway is nothing to write home about for a two seater. I have nothing against high power sports cars for the track but I have issues seeing them as daily drivers on the public roads. No-one needs to be finding themselves suddenly competing with them at intersections where their superior acceleration makes them unpredictable and therefore highly dangerous to every other driver as well. You can see examples from dashboardcamera.com. That said, this technology was more than likely developed on those single cylinder test rigs and the findings will be equally applicable throughout a range of 2,3,4 cylinder engines if GM decides to move in that direction.

The Japanese companies are making a number of their plug in cars compatible with charging the home, after experiencing how useful it would be after the tsunami Couple of immediate problems with that. The increased cost of burning a fuel with a heavy road tax attached in order to provide domestic electrical energy is unlikely to be economic. A residential house - despite being required to have a 200 Amp service entrance - only needs 1kw on average. That said, the inefficiency of an idling 70Kw generator must be evident. If you happen to be interested in CHP for the home you might know that Honda makes a small 1.5Kw generator which runs on natural gas and extracts thermal energy from the exhaust for space heating. The Freewatt CHP system is available in the States but not in Canada where a marketing start up was prematurely shut down in 2010 - I presume because CHP has the propensity to allow the natural gas companies to provide competition to the electric utilities since you could effectively run off-grid. I read somewhere that although the residential energy demand is one third of the load, residential billing provides two thirds of the funding. Sure the authorities allow you to put up a 20Kw PV array or even annoy the locals with a private wind turbine tower, but a CHP system the size of a fridge is dangerous disruptive technology since its widespread adoption could prevent the privatisation of profits and socialising of costs necessary to support the electrical infrastructure for govt and industry. /rant mode off. Anywhere in the snow belt I would rather see the use of 4WD to be encouraged for safety reasons rather than putting folks through the mandatory procedure for storing and installing snow tires as required in some areas right now. The Mitsubishi 4WD system has the advantage of dispensing with the mass of a transfer case and the mechanical inefficiency of turning power through 90 degrees to each axle. A win win there I think.

Honda plans to offer a lower cost version with a smaller battery than the present 6.7Kwhr which will follow on later next summer. As a reminder to those who choose not to go deep on the flagship Prius technology, its battery is 1.3Kwhr and I expect Honda to select something of that size. Personally I would prefer the idea of just having an electric transmission minus the expensive "boutique" battery part. In the absence of this high voltage battery, regeneration could be made through a radiator mounted braking resistor. Who knows perhaps this could happen later. I am not a particularly great fan of BEVs so I welcome the so called series hybrid approach with the engine coupled in by a simple clutch arrangement. I haven't seen the actual layout but I would assume that the motor to wheel ratio of around ten would be accomplished in two successive steps of 2.5:1 and 4:1, if so, then it would make sense to clutch the engine onto the intermediate gear shaft of that arrangement.

I'm not sure I follow you on the other stuff, but maybe you should elucidate. I would prefer to take technical discussions over to AEVA or DIYelectric car where you can still locate the thread or topic months or years later. Unlike say,on GCC. For AEVA, "How to convert a hybrid" has some thoughts on base speed placement. On the motor controllers forum, I've just started a "14000rpm motor" topic where I intend to discuss the narrow interest of induction motor rewinds for fractional V/Hz and single stage reducers. Perhaps later, if you have the time that is.

If successful, the project will allow technologies to be considered for possible future mass production. The Australian Government’s Green Car Innovation Fund is contributing A$3.55 million to the project. Let me see if I've got this right. "It will be considered for possible future mass production, if successful." So as I understand it - being successful is not going to be enough ? It will still need to be "considered". Who decides that ? And if they decide not to, do the Australian taxpayers then get their $3.55million back ? I have a better idea. How about not running these cars around for two years racking up the miles ? How about getting them into limited production first (like Tesla did) and let the market decide ? Early adopters will always find some problems a lot quicker than an evaluation team can ever hope to do. Or is this really about trade protection for Holden against Nissan ? Let's see, a Leaf is $37-39,000 in North America but with the help of the Australian govt is jacked up to $59,000 in Australia. Hmm.. Isn't that price differential going to diminish the number of possible Australian sales big time ? Excessive tarriff barriers on tested EVs that happen to be available right now has turned out to have been a fairly successful policy so far. It was found recently there to be only around 59 registered EVs on Australian roads today according to AEVA members who have been checking- see their website. With Nissan pushed out of the way Holden et al. are free to dawdle their way into the future selling two more years of gasoline only cars while greenwashing themselves with the Innovation Fund.

I see that MG2's planetary has been replaced by the yellow gearset (in the diagram). The path from MG2 to the wheel axle is therefore about 5% more efficient while stiil achieving approx the same reduction ratio. For myself I am waiting for the fully decoupled engine. Hopefully the introduction of BEVs will optimise the elctric powertrain so that a performance two cylinder engine-generator can replace the $12,000 battery pack to give us effectively the first affordable fully electric transmission. IOW the Fisker Karma without the Justin Beiber price !

-E-P thanks for responding. Perhaps I can convince you. It's times like this a telephone would come in handy ! I wrote: "Now let's increase both input frequency and voltage, and speed that machine to 12000 rpm while still providing the same torque and drawing the same current. At the finish the motor will be putting out eight times the mechanical power..." You responded: No. You've only doubled the input power (voltage * current); you cannot get 8x the output when losses were only 8% to begin with. In my example I was multiplying by eight not two. I should have been more explicit. Normally we rewind for a lower V/Hz for EV work so that voltages stay within reason. For our immediate purposes we could assume this to be a 100Vac motor @ 50Hz going to 800Vac @ 400Hz. An eight fold increase in rpm and voltage, with current and torque held constant. But You are correct that if I began with 8% loss, then I really started with 92% output not 100% ! At 400Hz it will be absorbing eight times the electrical energy and outputting 800%-8% =792% So the hypothetical power ratio is 792/92 = 8.6 not 8.0. So far, no one has disputed that 792/800 = 99% overall figure however. You are the first to point out that initial error in my argument however. Thanks. In the past people that I've run my argument past say they are just uncomfortable that running a motor faster under certain conditions can improve the efficiency of the machine. It kind of goes against the laws of nature and smells of the fictious "free lunch". But to continue..... Accepting that copper loss is independent of rpm is one thing, but of course no-one with integrity could neglect the effects of the iron loss which are expected initially to be equal to the copper loss at rated power. They would naturally get worse, hysterisis at frequency and eddy currents at frequency squared. In actuality it appears that you don't get anywhere near all the iron loss that text books would have you believe. Sure car alternators get very lossy if you keep constant field and rev the engine. But look at the lamination's thickness. When the bean counters are watching your back you get the thickest and therefore cheapest lams money can buy that still allow you to make spec. But that's in the auto biz. Industrial motor design is usually to a higher order due to IEC regs and with the newer high efficiency motors even more so. So eight times the hysterisis iron loss works out to be eight times practically nothing. Eddy currents appear to follow a 0.7 exponential law in real life, with the 4 times frequency testing, done privately, so far. Assuming constant current and torque as before, then inputting 4 times the frequency and receiving four times the rated power is one thing, in practice only a 4^0.7 = 2.6 continuous rating is useable however. In other words motor case temperature remains the same, admittedly with the fan working harder, if you pull only 2.6 times and not 4. The transient power needed for vehicle acceleration remains available at a true 4 times. And there is still a 3.5 times current increase over that to pullout, but then you're buying into 10 times the copper loss. For the few seconds needed it may be cost effective, if the battery can bear it that is. Other losses including friction and windage of the rotor are minimal, although removal of the integral fan and installation of an external blower, temperature controlled, has been suggested. I mainly wish to make the point to others that high rpm motors will always show better efficiency figures by virtue of their rpm and it is not something to get too excited over. That said this GE motor is mighty small for a 30Kw continuous output, too bad it is made out of unobtainium for the rest of us. This is the size of motor they should option for the Nissan Leaf for use in the inner city with gearing for 100Km/hr rather than the 150Km/hr 80Kw it currently has. I omitted to discuss slip strategies here - but it would take more pages than the moderators would want. Suffice it to say that you describe slip as a %age but I was seeing it as a fixed value for constant torque, independent of rpm. The back emf would be in proportion to the velocity of the rotating flux. Beyond that I haven't given slip too much thought since the modern idea is to keep the stator further away from voltage saturation by employing inverters with much higher current capability and even lower V/Hz motor windings, which allow base speed to move higher up within the total speed range, than would have been done in the past. Optimising for the motor rather than the inverter, if you will. Concern over slip has taken a back seat but I will consider the ramifications I might be overlooking so thanks for that.

-MG I agree, let's see those numbers. Otherwise I too, am not impressed. Regarding this motor - its maximum rpm is 14000 rpm. Or perhaps more accurately, still only 14,000 rpm. Should you want to find an AC permanent magnet motor exceeding 14,000 rpm today, then look no further than the Prius in the back lot of your local Toyota dealer. Under the hood you will find not one but two similar machines, one in particular is rated 60Kw. So, certainly no earth-shaking mechanical improvement there. Anyway the aircraft industry have been using 12000rpm 400Hz motors for years. They are not foreign to GM either. Their first experimental AC powered car, the Electrovair II used a motor which maxxed out at 13,200 rpm and was also liquid cooled and this was way back in 1966. Some 40yrs later the Tesla Roadster has to manage with a motor that barely exceeds 13,000rpm also. I would point out that since these motors are coupled to single gear ratio reducers, faster would be better. So GE's research comes up empty in the one parameter that certainly would be of interest. Let's discuss efficiency. I have put forward that the copper loss i.e. the electrical loss in the stator wiring is constant per unit torque. This holds whether the motor does 10 rpm or 10,000 rpm. If you accept that premise then it follows that efficiency improves with rpm. For example a 1500 rpm machine having 92% efficiency. It must therefore have a loss of 8%, you would agree ? Now let's increase both input frequency and voltage, and speed that machine to 12000 rpm while still providing the same torque and drawing the same current. At the finish the motor will be putting out eight times the mechanical power while incurring the exact same copper loss it did at the start. The same current remember, the current itself was not changed and remained constant. So if we have the original electrical loss accompanied by an increase of output power of eight times, this can only mean that the effective efficiency must have increased to a figure of 99%. But what about the iron loss in the stator shouldn't that increase big time ? Well, No. Build the stator with thinner laminations - like those found in 400Hz aircraft motors - and problem solved. Next steps include a four-year project, during which time GE engineers will seek to produce a motor with similar performance characteristics, yet with no rare-earth magnets. The problem with rare-earth magnets is that they are temperature sensitive. If the motor is allowed to get too warm they begin to lose their magnetic properties. Hence the necessary liquid cooling. The other disavantage with magnets is the fact that they are always "ON", so when coasting in an electric vehicle there is always going to be some drag from that previously mentioned iron loss despite the use of thinner iron laminations. This braking effect offsets their very slightly higher efficiency obtained when motoring. Ordinary induction motors can run safely at higher temperatures and may obviate the necessity for liquid cooling in some applications. Perhaps GE is going to investigate them next. Look - in case any entrepreneur happens to be reading this - what the industry or the aftermarket could probably use is a SRM or induction motor design with a 3 : 1 planetary reducer built into the end bell of the motor which can be coupled into any front wheel drive vehicle out there, after removing the clutch and gearbox. Engaging the final differential gives the overall 10 : 1 ratio that a hi-speed machine needs, since most auto gearboxes will not accept anything like 12000rpm in their 1st and 2nd gears.

Well said, TT In other news : Michael O’Brien, Ford electrified vehicle marketing manager. I wonder if there is an equivalent Ford gasified vehicle marketing manager.

A problem for introducing technology into the trucking industry is that the trailer is often used for storage and is not owned by the tractor company. Therefore you need to diminish the cost of the trailer. For that reason it is unlikely that the expense to install induction motor drive to the rear wheels will be justified. However I am still of the opinion that electric transmissions in the tractor unit make sense since the top speed range is much lower than for cars, 110km/hr, this encourages the adoption of a single gear ratio to be optimised for the acceleration needed at the lower speeds. Also an induction motor can hold its max rpm indefinitely unlike a reciprocating engine. Furthermore that speed can extend out into the 10k rpm range which multiplies the power of the motor. Eg a 50Kw frame size traction motor for 1500rpm becomes a 350kw motor at 10,500rpm, same weight and cost just different winding and a rotor balance. The same speed advantage can be used for the generator itself which would be geared up 1:4 from the diesel engine by a planetary perhaps a tad larger than the coke can sized Prius planetary which handles only 100Hp but nothing as large and as heavy and as complicated as a modern 14-speed mechanical unit. I would be remiss also if I didn't mention that traction motors are capable of delivering full torque from rest and in fact can deliver up to 300% torque with a 30 sec rating without requiring a corresponding increase in torque from the diesel although the engine controller may require it to run faster at this time.

-RP NiMH self discharges @ 18% /week LiPo battery much less, I don't have exact figure. The Prius GENII starting from MY2004 Prismatic cellpacks 7.2v 6.5Ah 1300W/Kg 46Whr/Kg 1040gms Prius NHW20 28 Packs to give 201.76v Total Energy 6.5Ahr x 201.76 = 1.3Kwhr Theoretically 1300W/kg @ 7.2v ~ 180 Amps Software imposes limits : Actually Max current when motoring 100 Amps Max current braking regeneration 50 Amps To depletion 6.5Ahr @100 Amps = 6.5/100 * 60 = 3.9 mins For 100% - 0%. SOC In practice only 80% - 20% range of SOC is used SOC (= State Of Charge) Total Power Although 180A x 201.76v = 36.4Kw available Software limited to a max of only 21Kw The Gen III with 27-Kw therefore is the same NiMH battery Why the previous de-rating ? standard reason : To reduce warrantee claims And I bet toyota engineers like to sleep nights. Expect the same when the NiMH is replaced for the 2014 MY with Li-ion, supposedly.

micro-turbines !! What !! no mention of photovoltaics, stirling cycle engines or hydrogen fuel cells ? Just as well, I woudn't want to be reaching out for the blood pressure pills. Any more than I'd want to be reaching out for that two speed gearbox if bringing down the top speed from 75mph to 65mph could make that disappear. And, jog my memory, but didn't Tesla abandon their own two speed box to save the company. I'm funny that way, if I see something mechanical like that then I start to think that if something can go wrong it will go wrong, and like ice dropping on the wings of the Spaceshuttle, failure won't be graceful. The software may be ironclad but what if a faulty sensor or a stiff actuator..... ? Can anyone be that sure ? I'd guess at those times investors will no longer seek out Mr Wright, they'll be looking for Mr Close Enough.

When diesels are considered in conjunction with multiratio transmissions it should borne in mind that there is a very restricted RPM range here with diesel fuel as compared to gasoline. Whereas modern gasoline engine design is good to nearly 7000rpm with constant torque, its diesel equivalent is only good to 2400rpm while its torque curve is firmly bent over with its shorts around its ankles by 4200rpm. Expect to see a 33% roll off and that's with turbocharging I might add. The perseverance to persuade what is almost a constant speed prime mover to be useful in a variable speed application - which is what a road vehicle is all about - never fails to surprise me. Hey fellas this is 2012 not 1950. I would've thought that 2 million Prii have more than proved that decoupling the engine from the wheels is the way to achieve the ultimate in downsizing. In most circles it has been acknowledged that the 1.5L Prius powerplant is more than able to match the performance of a more conventionally coupled 2.5L Camry engine. Yes A D I concur, this is your tax dollars at work