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Davmart, I would like to speak to your comment as one who has relied on public transit until recently and is also a very minor stockholder in Tesla Motors, to which you just made an oblique reference. But first, on public transport. When service frequency is sub ten minute, public transport is akin to being chaufeured around town by the government which is of course somewhat fiscally responsible, I suppose, in hi density areas. The problem is that when authorities are charged with providing a suburban route at a price that makes financial sense it ends up with you, the consumer, being constrained by a 30 minute service with the circle route that puts you on the twenty minute neighbourhood tour you would rather not make. It's really hard to be anywhere near cost effective when the chauffeur has to be paid at a rate consistent with possessing an equivalent AZ license (about 3 times minimum wage against what most of the passengers are probably earning) while motoring around in an eight ton vehicle. Outside of North America some transit authorities are addressing the cost issue by adopting the use of microbuses, for their feeder routes I assume, similar to the airport shuttles with which most of us are familiar. In the mean time private companies here in NA are not eligible to bid on the established routes which are operated by members of a public service union. There is also the hidden cost, paid for though property taxes, of the significant damage these larger vehicles do to the roads they frequently travel. Tesla will continue to make cars for the rich since this early stage company needs the high margin sales while in expansion mode so they can be ready to support the market when the demand escalates for the entry level luxury models at around $50K sometime in the next four years. Despite the fact they sell product that meets current legal requirements, I too would like to see a world where 7sec cars and 100mph represent the upper limits on speed and acceleration. I apologise if these comments seem facile to you. I have had to put up with comments on the Tesla website where there seems to be a breed of car enthusiasts out there who want every car Tesla puts out to be a track car. You can see the frustration when another poster responded "so if I have got this right you are wanting almost the same performance as a Model S has now but at $50K, in other words then what you're really asking for is for Tesla to knock $40k off their price for a Model S and you would be good to go !! LOL"
Good video. Thanks. I posted a link to it from Tesla Motors site. I can't make them smarter over there so at least I can assist them to be informed ! The video runs for more than an hour. Here's what I took from it. The video begins with Prof Dahn of Dalhousie U. discussing battery longevity issues brought on by charging. It is known that charging cells when cold is beneficial to slow the formation of a coating on the surface of the cathode material. Consequently a useful strategy is to ensure a limit to the time that the cell is heated by the charging process. It follows that speeding up the process at a rate of around 1.5C gets the process over quickly so that the cell can be cooled immediately and so curtail the time window for the coating to form. Throughout this video, made last year, Prof Jeff Dahn makes several references concerning Tesla Motors. In particular mention is made that one of the original researchers, Aaron Smith, had moved over to Tesla in March of 2012. At Dalhousie, Smith was involved with the assembly of test equipment to measure the exothermic generation, at the tens of nanowatt level, during the parasitic formation as separate from other heat sources within the cell. Prof Dahn goes on to say that apparently discerning the difference between microwatts and nanowatts is key in predicting the coulomb efficiency drop off. Of course when the cell cathode is totally plastered -so to speak - and drop off in performance now becomes more rapid, well that particular condition remains harder to quantify. However the enhanced measuring techniques mean that you don't have to put a cell through thousands of cycles to determine when its useful end of life (80%) is likely to be. Further insight into cell design was given that it is not just one compound that improves longevity but the synergism of several additives and that is making scientific progress difficult. It appears that a twentyfold increase in cycle life can be made by a mere 1% addition of one new substance providing other electrolyte additives are present in the right quantity. On the other hand if you're not optimising the additives but think that you can just try to figure out the mechanism of why they work the way they do then you're CRAZY ! That's with the equipment now being used at the current SOTA, I am assuming. Bottom line. As a first choice it is actually more preferable to be using Superchargers than even L2 chargers but only if the cells are cold. Racing between superchargers thus needing to visit more supercharger stations on your route - assuming circumstances permit - is not so much a good idea, unless the Thermal Management System has been able to precool the pack. Charging from 110Vac won't introduce much heating, of course, but it might be better to be doing it when the battery is known to be cold. I guess the use of these techniques requires a name analogous to hypermiling.
Otis, from your previous two comments I see that you are pushing for larger batteries until battery tech catches up. Here's the problem I see with that. When is enough enough ? I think even at $150/Kwh the 24Kwh Nissan Leaf would have a $3600 pricetag. Not surprisingly there are many out there who are demanding double that for what they consider to be a viable car. However the case for future transport should be that "the purpose of cars is to primarily transport people and not the carriage of tons of chemical material through the streets". A single occupancy Model S weighing over 4000lbs is not the answer when some are purchased to gain unbridled access to the HOV lanes. My deal is with the Superchargers which permit range extension for any size battery and the way in which they are being introduced to the market. In particular the free use aspect. When free use is permitted on anything, like supercharging in this case, then most people are going to want to capitalise on it. Again human nature being what it is, a better strategy may be to impose a minor fee per use. Overtly this stategy might discourage bunching up around supercharger sites which is very likely to occur as the population of Tesla vehicles escalates, while achieving the underlying purpose of serving to avoid or mitigate any possible, but as of yet unproven, acceleration in the deterioration of battery capacity. A condition vehemently denied by Tesla supporters and something I hope will turn out not to be the case when more data is available. However you have to be aware that a negative outcome carries the risk of additional financial implications to Tesla since the company has pledged to support the resale price to the original owner. The idea is that providing a backstop on the residual price will enhance the value of the brand and encourage future sales. Meanwhile at Tesla, software designers may be taking advantage of the vehicle knowing - through the touch screen - when the vehicle is about to be visiting a SC site and will use the intervailing time by supercooling the battery enclosure in anticipation of the event. This proaction should ameliorate the effect of heat which will eminate from those 8000 individual cells during the subsequent sustained recharge at an ~2C rate. Marketing at Tesla has taken the stance of saving on cost and to rely on word of mouth advertising, in which case they might try an assurance to remind consumers that " Whenever you leave home you start off with a FULL TANK". A sentiment that costs nothing but may dispel thoughts of range anxiety. Is it also too much to ask that marketing will better connect consumers to the effect of speed on range ? I find it somewhat circumspect to benchmark range at 55mph in order to enhance vehicle capability on paper. Is it safe to say that no one who has paid out close to $100k for a Tesla is going to be satisfied by driving it at that speed unless, of course, they happen to be in a 40mph zone ?
Which battery chemistry can be charged at 3C regularly and be economically warranted for 8 years and 100000 miles with no more than 20% capacity loss ? - Otis Good question. I also have raised concern over Mr Musk's assertion - at a press conference in England recently - that Tesla users should use Superchargers all they want. Trouble is I brought it up on Tesla's Forum. This was in rebuttal to comments from new owners, made on the "potential buyers" thread for Model S where they immediately called me a troll. I was asked to provide a valid source for my assertion. Well my experience is with the DIY crowd using Pb-acid batteries. We made sure our members were informed of the care and feeding of Pb_acid battery packs from our monthly newsletter. Apparently this was not good enough for the moderators (admin). They said Li-Ion was not the same as Pb-acid in other words I was making an orange to lemons comparison. At which point I challenged them. I said that since they were the ones making the claims they should be the ones providing the proof and not the anecdotal proof that some members came up with. Anyway their response was to move my subsequent posts to the OFF TOPIC section. Why did Musk make the assertion ? I'll apologise for him. He is very much an engineer and you can often see him choosing his words slowly and wisely unless he has opportunity for a canned reply in which case he reels off a professional delivery. In this case I think he was tired and the journalists caught him off guard. Three things you need to consider. The Supercharger option is free to those with the Model S equipped with the 85Kw pack which is a high proportion of the approximately 40,000 cars made. Most of the vehicles are still less than two years old. Any data collected by the more than 2600 Roadsters now approaching four years old is non applicable since their internal circuitry will not allow them to accept the 120Kw DC charging from the Supercharger. Bottom line is that supercharger use should be judiciously taken until we have more data. About ten years ago Sean O'Keefe, chief administrator at NASA, in a televised address, mostly to Nasa employees regarding the transformation that NASA would be making to avoid another Columbia disaster, made a particularly honest appraisal of the situation. Apparently when it was first noticed that lumps of ice were breaking away from the upper part of the LOX tank and striking the re-entry heat tiles on the undersurface of the SST as it lifted off the pad, the reaction from observers was subdued. No one would blow the whistle on it - most could make the case that it wasn't in their job anyway - and subsequent successful launches gradually dispersed those who had been accused of unwarranted paranoia. As the shuttles began to be reused any broken tiles that appeared on the heat shield were replaced as a matter of course. Ice falling on to the heat shield was no longer considered a problem. Everthing was fine for many years. Then 2003 happened. Later on, investigators were able to pull down lots of video with sheets of ice raining down onto the shuttle's shield. Perhaps the risk being assessed as being marginal was in fact not the case. How about that any statement inferring minimal ice damage to the orbiter was less than true in fact could it be a big fat lie ? Mr O'Keefe continued. You have a developing situation at Tesla where a $100K car can be leased with little investment from the driver. Then you set up a situation where high power chargers are free to use as often as needed. If the battery pack is degraded by this practice it will be the shareholders - that's where I come in - who will carry the can for the warranty replacements. Nissan's battery warranty protects the company by specifying 1100miles/month + 25c /mile overage or something like that. Finally Proof of Life is not set out for when these vehicles become CPOs in the automobile market. The battery is a big part of an EV. How accurately can the state of the battery be measured for a future buyer ? Owners report that even on-board range estimation still leaves a lot to be desired.
Limited range EVs make sense only UNTIL batteries price drop to $100/kWh. - HarveyD JB Straubel, CTO at Tesla, has stated, and it's on Youtube now that I remember, that the absolute lowest cost with an acceptable profit margin looks to be $120/Kwh. But he hastens to add that you don't even need to wait until then since it is believed that by the $150/Kwh price point you will already be seeing the death of the ICE passenger vehicle.
International Rectifier supplies the major semiconductor modules for the current Tesla Model S and the previous Roadster. Details on the IR website. Hopefully the fact that a German company is now involved with Tesla will cause a spurt in sales to Germany which have not been all they could be. Teutonic pride and all that.
As someone who codes microprocessors in real time apps and has spent a couple of years studying thermodynamics bringing these two disciplines together is quite interesting. On the electronic side, as a real life example, Chrysler 4 cylinder engines use a set of crankshaft negative-going strobe pulses with intervals at 69,49,29 and 9 degrees before TDC for each pair of cylinders. 1&4 or 2&3 resp. That way the piston velocity can be accurately computed using input compare registers to time stamp these pulses. This enables the second operation which takes a previously computed ignition point (in degrees) and loads it as a time value into the output compare register such that when this value compares to an incremental 16 bit free running counter the output pin on the chip will change state and activate the igniter. Those not in the business may be unaware that this can be done with half a microsecond accuracy without any regard to processor latency. This is in sharp comparison to the timing variability exhibited by old style switch contacts on a distributor shaft with a degree of wobbility. However.... The elephant in the room is that the mere firing of the igniter at precisely the right time has very little to do with accuracy of the ignition of the fuel. The flame wave front as the fuel burns is less predictable in time. It follows a bell curve type distribution so it is difficult to get a perfectly running engine at slow speeds, despite the timing being crystal locked to the rotation of the crankshaft as I described. In the past solutions have entailed the fitting of dual spark plugs or more complex firing patterns of several pulses. The industry seems more motivated, now that the hybrid premium is being gradually whittled away, to get the efficiency of non-hybrids raised. A spark that is 1000 times should do it ! With that sort of energy I am thankful that it is accomplished within the body of the plug
E-P , I remember that policy being enacted in 1975 when a cartel was formed to allow the Canadian Govt to harvest more of the windfall profits of nuclear energy. (can't let the public have power too cheap !) Gary, you brought up $500/Kwhr battery storage. Elon Musk's intention is that the imminent building of vertically integrated Gigafactories for Tesla will be an initial attempt to bring lithium cells down to $200/Kwhr and make viable the supply of EVs to the masses. BTW if $150/Kwhr is ever achievable, the gasoline engine becomes a museum piece shortly after. Looking further ahead some have pointed out that even that accomplishment could turn out to be merely a sideline business. The real thrust will be in energy storage to challenge the electrical utilities - for those who continue to favor the idea of centralised distributed power. Although storage is absolutely essential for wind and solar, there is no reason I can see why nuclear power couldn't benefit also. Surely there is significant financial advantage to be gained when permitting load levelling to take place such that nuclear reactors could remain at 100% output for the complete duration of their service life, that is until decommissioning becomes necessary ? Obviously this would allow the displacement of the burning of much fossil fuel. What has to change is the very idea that it is acceptable to use the oxygen of the air as a resource when it is an absolute necessity to human life.
@DaveD, I agree that a low c rate will prolong battery longevity and supercaps can help this by suppressing load peaks but that would appear to go against other determined efforts to encourage the use of even more trips to the Supercharger. I wonder if you are aware that Tesla has a design team investigating the use of supercooling the battery enclosure when the driver has indicated that the vehicle is to be stopping at the next supercharger site. The intention is to have the pack prepped such that it is less vulnerable to the effects of internal heating during high current recharging. I am concerned that the 10% degradation per year measured for continuous usage of a supercharger will make resale of Tesla vehicles or any EV, for that matter, a difficult process unless a verification of remaining battery life can be assured to the buyer.
Hi, Roger, I was trying to make the point that you should not be needing a dedicated upconverter to supply high voltage to run 3-phase motors in a BEV. But you still wrote Upping the voltage is important to reduce the size of the motor by running at higher rpm and in so doing, will reduce weight and cost. The fact that Toyota was using an upconverter inside its HSD is an entirely different application in which it was necessary to stabilise an otherwise wildly fluctuating bus voltage by augmenting the bus voltage to 500Vdc from a 201V battery source. In retrospect I now regret I even brought it up. On the other hand when used in a BEV, the use of upconverters would force a more complicated two stage process. It is obvious to me that the root of the problem could be solved by having the motor wound with the correct V/Hz in the first place. Such low V/Hz motors have been around in aircraft usage for decades. Mostly rated at 100Vac @ 400Hz meaning V/Hz = 0.25 and with direct online starting capability. Much different from the industrial machines of 480Vac/60Hz which have a V/Hz of 8.0. -DaveD wrote about the promise of supercaps ability to harvest regen energy and perhaps be pre-charged with enough energy (560Kj) to permit rapid acceleration from rest without caning the small battery in a HEV. Well, last year I might have even agreed with you on that, Dave, but today I see HEVs as bridge technology to keep us tied to the oil companies. Same reasoning to have us transition over to Hydrogen based FCEVs. Roger and DaveD it's time you came over to the Dark Side and joined me where passenger cars are concerned. In a future where you always charge at home and leave the house with a "full tank" every morning. And perhaps twice a year for those longer trips you'll be using one of them there superchargers somewhere out on the major hi-ways. At the moment you guys are thinking like my father once did. You were probably not around sixty years ago when most cars had a hole cut into the radiator at the front of the car where you could poke a starting handle whenever a flat battery required the engine to be hand cranked. Eventually the point was reached where manufacturers could abandon that convenience feature. Clearly that point was reached a little too early for my father. I remember his consternation about having to buy a newer vehicle with that radiator hole missing. "Starting handle anxiety" they would have called it.
DaveD wrote This is an incredibly important advancement. It's nearly as important as the batteries themselves as the inverters, converters, etc weigh as much as the electric motor Nope, I beg to differ, today's inverters are good enough. And "good enough" is not the enemy of best. Toyota has SiC technology as well but have said they won't be rolling it out until 2020 at the earliest. Side view mirrors being replaced with cameras would be a significant advantage when motoring at speeds beyond 50 mph and I would expect them to net significant gains. Public acceptance of slightly unusual aero dynamic body shapes would be helpful also. It is the rear of the car that needs fixing up with a boat tail. of course autonomous vehicles running in a close formation will mitigate aero losses as well. I would speculate that any 100 mile car @ 55mph would become at least 120 mile car @75 mph when travelling in a convoy. Don't expect profound battery improvements anytime soon. Real world improvements in battery technology seem not to be following Moore's Law. More like 7% per year.
Upconverters have been successfull in automotive applications for quite a few years. Toyota happens to use them in 650Vdc circuits using just silicon devices. The introduction of an upconverter from 2004 onwards in the Toyota HSD powertrain for the Prius was undoubtably a game changer in HEV performance. For one thing it allowed the previous battery voltage to be lowered from 273v to 201v which permitted the use of fewer cells in the battery pack and a useful cost reduction. You have to bear in mind that the original 273V battery held only a miniscule 1.3Kwhrs of energy yet required 38 sets of battery modules each consisting of six 1.2v NiMH cells. However the major advantage of an upconverter in this application was that it enabled the inverter system bus to run at 500 Vdc even when the generator MG1 was forced to rotate well below its max rpm which would have otherwise crippled the operation of the traction motor MG2. The circuit which employed a dual mosfet upconverter performed both the role of raising the 201Vdc battery pack to 500Vdc while at other times returning power back to the battery pack when circumstances allowed or when the battery was needed as a 10Kw power sink during regenerative braking. As regards HEVs, in a climate which finds increasing numbers of roadside superchargers being installed, I see less and less need for an ICE in the vehicle to be necessary either. The HEV is a bridge technology whose time is running out for passenger cars and delivery vans. Except for transport trucks where it may become the niche market. I also don't have any enthusiasm for the installation of supercaps and flywheels also mentioned above. All I see is a complication with a questionable cost justification. In the situation of a pure BEV I just don't see the need for modulating the main bus voltage in this way. High current devices with low V/Hz motors are the way to go. I certainly would not advocate the implementation of an artificial 750Vdc bus just to permit the use of lower current devices in the traction inverter. If the goal is seriously to improve effcy then maxing out top speeds in the vicinity of 65mph should be the goal, that way punitive aero losses can be prevented. It seems that funding for SiC semiconductors is being used here for studying different powertrain architectures. May I suggest one useful research direction which I believe deserves investigating specifically is the use of multiple traction motors: Given TWO motors is it better to have each of them installed on the same axle for individual wheel drive or is it better to have each of them installed on different axles for AWD ? At least Tesla, for one, seems to be taking that latter approach with AWD for its Model X slated for limited production in 2015. My preference in powertrain improvement is any move towards the elimination of the open differential. Anyone agree it's time we abandonned this rube device of the nineteenth century together with its unpredictable tendency to lose traction in adverse conditions. So there it is, I am viewing individual wheel drive on the rear axle as preferable with the additional opportunity to provide torque vector steering and traction control. Perhaps a motorsport company should be taking a look at this.
For the longest time I was an enthusiast of gasoline electric HEVs but I finally caved this year when Tesla began installing continent-wide, a Supercharger network providing free usage with Tesla models equipped to use them. Someday Peter Martens & co. should try out a drive in a Tesla Model S. Perhaps then Volvo might reconsider changing their course away from the ice-age era.
Biff, supercaps tech is currently at 10Wh/kg while the best lithium cells are capable of 270Wh/kg. OTOH I'll agree supercaps are great for supplying peak power for acceleration but for energy storage, not so much. I agree re flogging small motors, probably not much gain there. The problem is that when the mass of a large motor is swamped by the mass of the vehicle it is installed in, then for equal performance it is probably to be expected that even a smaller and lighter engine will end up consuming the same amount of fuel. Sure, the smaller motor should offer the option to obtain higher mileage but if the driver chooses not to do so - then perhaps the problem with fuel economy lies with the driver and not the powertrain.
GM ranked No. 1 in total fuel cell patents granted in 2013, and continues to lead all companies in total fuel cell patents granted since 2002 And are these partially taxpayer funded patents going to be made open domain as Tesla just did with theirs to further the cause ?
Marketing needs to get their nose out of this project. R19 tires ?? The use of a parallel twin engine should have been considered. Modern three cylinder engines will develop enough power to exceed 100mph - seems no sacrifice there. I would have expected they would be looking to develop both a lighter and less powered vehicle. Dropping down to the two cylinder arrangement permits slightly more power per cylinder since with the 3-cylinder thermal limitations will apply to the center cylinder. Savings in the electrical component complexity also since only one igniter coil is necessary as opposed to the 3-cyl which will require three. The Fiat 500 does quite well with its 900cc twin, although it is moderately turbocharged to 85Hp - but its 65Hp version when N/A isn't shabby either. I predict that in ten years when Elon Musk gets around to implementing his skateboard style of EV powertrain onto this size of vehicle, automotive gasoline engines are going to be consigned to history anyway.
I would comment on the use of graphical presentations by Audi marketing particularly when they are used for comparitive purposes. They might give thought to having them redrawn with equivalent scaling or better yet provide the torque curves and power curves on separate graphs.
Herman: Reading between the lines of the front end of your post I see that basically you're clinging to the ideal of the superior energy density of gasoline but retaining the option to adopt an electric mode at speeds below 10mph where it makes more sense, since it takes the equivalence of a continuous 5Hp or more just to rotate an idling engine. In the past I would have been in agreement with that position. Today, however, the ability to get a supercharge anytime with location help from an Android/Iphone app has changed my mind. Leasing as you are doing is a safe bet which leaves the risk of the residual value with the lessor. At the end of lease I would be surprised if the dealer doesn't have some device to check on the state of the battery. Regarding risk I remember that in the early days Toyota would not even lease a Prius and the finance on the purchase never received the beneficial rates offered to Corolla and Camry buyers. The early Prius were amortised over six or more years because their owners wouldn't accept the poorer offers. Fortunately for you the take rate on the Leaf has been somewhat lacklustre so the lease model had to be introduced to save them from languishing on dealer's lots. That said I expect that the cost of your lease already reflects a low residual price. Harvey: I have been following battery chemistry since around 1980. Sodium-sulphur and aluminum-air were both said to be promising at that time. I wouldn`t hold out much hope for 2035. People will eventually accept that these electric cars are going to become universal and form a disruptive technology to the automotive industry, possibly not here at GCC - Holdout Central - but perhaps most everywhere else. I recommend you go over to Youtube and take in Clay Christensens June 13th 2013 Clarendon Lecture at Oxford University. It's a corker and well worth spending the hour it takes to run and although he won't be telling you WHAT to think he may help explain on HOW to think when you face a disruptive technology. Which the vehicles from Denza and Tesla are going to be. The essence is that disruptive technology transforms complicated and expensive products into simple and eventually more affordable ones. This process is taking place right now. And the reason this process is happening right now, today, is because Elon Musk has drawn the conclusion that although billions have been spent in electrochemistry research the improvements have been merely incremental compared to Moore's Law applied to flash memory and until recently microprocessor clock speeds. Case in point, after ten years of using Panasonic cells, Tesla Motors is about to replace the original 3.1AH 18560 cell with improved chemistry that delivers only 4.0AH. I am not betting that this recent 5-5-5 program to improve storage cells is going to materialise either - other than a money pit - but as I said before Elon has already decided to go with what we have now. Ford GM and Chrysler; Toyota and Honda with their hydrogen fuel cells clearly use them as a stalling technique since they all prefer doing business as they always have. Sure Toyota came up with the Prius hybrid but you may have noticed that in almost 20 years improvements in that technology, specifically regarding mpg, results have been minimal. Those hoping to find some low cost remnant of ICE technology to be included in future vehicles should be prepared to be disappointed. Such vehicles will include more complicated and expensive internals compared to pure electrics where the mantra will be simplicity and affordability. I should disclose that I do not yet have an electric vehicle, my daily driver is a Toyota subcompact and I hold some TSLA stock.
If Tesla will settle for a 10-kWh PHEV, then Tesla's investment in the battery factory will be 1/8th as much. Clearly Roger you don't understand where Elon Musk, the man behind Tesla and SpaceX, is going with this. He is not just supplying a high end premium electric sports sedan. His mission is to use this disruptive technology to displace ICE vehicles including hybrids everywhere. Much as we like the Prius, that and similar hybrid cars today are merely a bridge. If Musk were just supplying a different sort of car into the market, that would be one thing, but he realises that the infrastructure to support long distance travel with electric vehicles requires providing both the 85Kwhr battery packs inside the cars as well as providing a network of Supercharger installations externally. In that regard 100 Superchargers are already up and running across the United States. Last week he visited Shanghai where they have three Superchargers installed already.While there he was gifted with 3000 vehicle plates worth $16,000 each, since new vehicles can only be sold and registered there after an existing vehicle has been removed. Apparently it is not just North America that seeks freedom from harmful emissions. This maybe didn't make the news because the media was preoccupied with the Ukraine crisis. For those who may not be aware these Superchargers are designed to bring a discharged 85Kwhr battery pack safely up to around 80% State-of-Charge in about twenty minutes allowing the driver to put on a further 200 miles until the next refill. People who need to make longer trips will probably opt for jet travel anyway. Incidentally there are some observers who are convinced that even demolishing the established automotive industry model may turn out to be just a sideline business ! The real goal is certainly to bring battery storage down to $150/Kwhr with economy of scale and extreme vertical integration manufacturing. Attaining that price point will certainly threaten coal fired utilities since it will allow existing nuclear power stations to run very close to a 100% loading 24/7 by installing battery farms in close proximity to urban load centers. The location of these farms would utilise existing feeder capabilities which are equally under-utilised during the off peak periods. I am going to overlook your enthusiasm for 100mph and stop light Grand Prix's since automatic two speed gearboxes will add considerable expense for very little gain. There are always going to be holdouts like you Roger who yearn for the status quo but may I remind you that gasoline has peaked at $1.3CAN/liter in some places in Canada right now. OTOH a Nissan Leaf owner on the radio today offered that his car can deliver 140Km on $2Can of electricity.
The trend I've been noticing in the performance of the current crop of electric vehicles entering the market place is that they seem to all be geared for top speeds in the range of 150Km/hr (93mph). The power required to sustain these orders of speeds in the steady state is about 30Kw. If it can be said that normal mileage claims assume a draw of 10Kw at 110Km/hr (65mph) then I can accept that it is one thing to be concerned with range anxiety while using power at this rate but to install a drive system that has capability to drain the battery pack at triple that rate seems somewhat incongruous. I am not in any way suggesting that 80 Kw drives system should be downsized or in any way reined in. One of the advantages of electric powertrains that is becoming increasingly appreciated is how they scale up in power with remarkably reduced incremental costs and simplicity compared to their mechanical counterparts. It is what has given the Tesla Model S the edge with 180Kw when compared to similarly sized cars in the luxury segment. What I will say is that marketing would do well to specify, for those less sporty vehicles, maximum speeds around 125km/hr (75mph). In the case of the Denza an appropriate gear ratio change of 150/125 will return 20% more wheel torque making this an eight second car to 60 rather than the ten seconds it probably does right now.
Roger , you have to stop with this rooting for range extenders. The future is going to be BEVs with the help of Superchargers on major highways. And if that isn`t enough there will no doubt be a healthy business for mobile chargers utilising former tow trucks that have been upgraded for capability to make a 20 minute charge. Unless there is a 50km stretch of major highway in your daily commute it is possible that you will rarely need to visit a Supercharger anyway. Most charging locales will be at home rather than that special place we are forced to go out of our way to refuel a gasoline car. This preoccupation with ice-age machinery will continue to bring with it those frequently necessary visits plus those for regular fluid changes for engine cooling and lubrication. From that angle electrification seems to be somewhat attractive.
Many years ago I looked at this problem. The hydraulics lab happened to have had a free piston engine dating from 1964. One thing for sure, that device certainly was noisy when running. And just like hydrogen fuel cells - as someone noted here - it will be tomorrows solution. ALWAYS. But it forces you to appreciate rotary motion all the more. However regarding rotating pulsating energy systems, the current practice is to use a crankshaft flywheel and a damper disk to smooth pulsations to a 3-phase generator which of course would prefer a constant torque input delivery. Noting that flywheels and damper disks are large and not inexpensive there must be some way to eliminate both these middlemen ! The mechanically "stiff" flywheel is not sympathetic to pulsating power and despite the use of a damper disk it is the cause of subsequent engine vibration. An idea I suggest is to electronically switch the rectifier tank circuit of the generator so that it would efficiently absorb the energy into an LC network and provide more of a dampening effect to the crankshaft. Basically you are understanding and accepting that the adiabatic expansion that forces the piston down the cylinder bore must be received with a counterbalancing electromagnetic force. A mechanical phasor would be required initially in the lab - the printing industry has used double planetaries for colour registration for many years - to align the generator magnetic poles on the rotor with the point of maximum thrust from the crankshaft. Consider that a single cylinder engine will provide one mechanical power pulse every 720 degrees. Consider also that a two pole single phase generator will absorb one mechanical power pulse every 180 degrees. Clearly one match would be to use a 4:1 reducer gear between the engine and the generator. Or one could take a four cylinder engine which would provide one mechanical power pulse every 180 degrees and therefore directly connect it to the generator.
Ferrite magnets ? It occurred to me that maybe we are misconceptioning the use of ferrite here. My familiarity with ferrite in applications is with high frequency transformers, specifically for its low hysterisis loss at high frequency, certainly not for its flux density or remanence. So that would make ferrite not a good candidate, I would think, to utilise on the rotor of a synchronous motor. However its use as stator material particularly at excitation frequencies approaching 600Hz would be an entirely different matter, especially since the stator is a lot easier to apply methods for cooling. Of course you would be looking at 18000 rpm with 4 pole machines although I would not rule out 6 pole machines for increased torque as long as the extra thermal load can be mitigated. My own preference is for the use of silicon steel since it will support flux densities up to 3X those of ferrite i.e. ~ 1.2T. I won't dispute the 2% efficiency advantage over ordinary induction motors, frankbank, but I wonder whether that figure allows for the fact that Field Oriented Controllers will automatically decrease the applied V/Hz on the stator when it is detected that the vehicle has attained its cruising speed and thus significantly reduce stator iron losses. Finally in the bigger picture, incremental aero losses at the upper speed range are more significant than motor efficiency. The problem is to find the most meaningful way to inform the driver. A Watt-hr per mile display doesn't quite cut it. Who knows what that figure should be ? Even the amperage is not the best indicator for the average driver as it will vary from vehicle to vehicle. OTOH if the expected Watt-hr per mile at 60mph, say, could be represented as 100% then at other vehicle speeds above/below this then specific consumption rate could be displayed as a percentage. The value rising above 100% as the driver slows down or falling below 100% as the driver begins to exceed 60mph. The hope is that the effect of the cube law on aero would be more dramatic in its presentation.
From 2011-2014 eh ! You can believe all the propaganda you want about this being a European effort but I see this predominantly as a German rebuttal to Elon Musk's Tesla Model S powertrain. Just 60kw today but obviously they will be scaling it up so that Merc, Audi and BMW will have something to fight with - when the time comes. Personally I believe they are already late for this party and the only thing I see holding back Tesla sales would be Teutonic Pride. Low cost powertrain packaging in the car is only one front they will have to defend. Not to forget that a good many of the 'no fee' superchargers have now been installed across Germany and the Bavarian region, prospective Tesla owners, like anyone else, will find the ability to avail themselves of this "Free stuff" compelling. Induction motors are the way to go since they are more resilient to high temperatures allowing them to tolerate a higher power density. Sure at low revs they don't compete well with magnet machines which provide flux fields with zero power loss. However the copper loss they incur to maintain unit torque remains constant, so as the induction motor spins up this loss becomes a smaller and smaller component of the increasing power being developed, ipso facto efficiency will improve proportionally with increasing rotational speed. I have found that the big problem is getting people to understand this since they are educated in an academia which is immmersed in the 60Hz world where slip is often referred to as a percentage rather than a constant which it in fact happens to be.
Herman, I could have been persuaded but a closer look at the KERS unit convinced me that their unit cannot possibly be manufactured for anything like $2000. But even if it was, there are still some serious doubts in my mind now that I think about it. A 60mph to rest energy capture is only about 600MJ in a Prius sized vehicle and that's if you can capture energy at an initial peak rate of 240Kw. And it pre-supposes you are going to be able to re-use that energy before the flywheel spins down. On the race track that is not a problem but in real life... ? Then there are these considerations at play. First, only the rear axle where the KERS mounts can actually harvest kinetic energy. Second, wheel skid would definitely occur if the system attempted to recuperate half of the KE (300MJ) in a reasonable short space of time. Third, it is only the front axle that has the ability to do any wild braking bearing in mind that the vehicle will attempt to stand on its nose during a severe emergency braking manouvre thus removing the downward pressure at the rear and therefore the wheel friction that the rear tires could exert. It also begs the question. How simple and reliable can a transmission be, that is able to slow down one mechanical system while speeding up another and shortly after have the capability to do the opposite ? Obviously this is race car technology that is looking for application in the mass automobile market. But where ? With an EV handling large amounts of regenerated power suddenly is never a problem. Whereas with a hybrid, braking power of only 10Kw seems to have significantly reduced brake wear, even though owners say it probably satisfies only 95% of braking opportunities.