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An Anonymous Coward writes:
Until now, electric cars could be broken down nicely -- at the high end there is Tesla S & X, and then there is everything else (possibly including Tesla 3). A few possible competitors either quit early (Fisker) or haven't made it to production yet (Lucid, Faraday Future). This split covered price, luxury and range. Now there is a serious competitor from Jaguar and Motor Trend tested the I-Pace in Europe. While they report trouble finding charging points (it's a new car after all), they generally seemed to be impressed.
As BEV platforms go, the I-Pace’s skateboard layout is conventional. There’s a motor at each end, one driving the front wheels, the other the rear, and in between is a liquid-cooled 90-kW-hr battery pack with 432 lithium-ion cells that also provides structural integrity for the chassis. The Jaguar-developed motors are synchronous permanent magnet units with concentric transmissions that align the motors with the axles. Total output is 394 hp and 512 lb-ft.
[...] Much of Germany’s autobahn is subject to speed limits, so we spend a lot of time at 75–80 mph. There’s not much wind today, but the higher speed boosts consumption to 43 kW-hr per 100 miles. On one derestricted stretch I wind the I-Pace up near its 124-mph Vmax. It gets there easily, but I burn 6 miles of range in the process (and yes, a gasoline version would also burn fuel with such a surge). Feeling guilty at the extravagance, I back off and settle down to 75–80 mph again.
(Score: 3, Interesting) by aiwarrior on Saturday June 09 2018, @01:25PM (20 children)
The motors while sounding special in the article are nothing, well, special. There has not been much improvement in motor design since the early 1900's. Where everything improved was in the control(oh boy did it improve) and driving
.
The transmission though is very interesting. I thought the future of electric was going to be in-hub motors with the differential electronically controlled, saving space, weight and parts in transmission and gears. The only reason I can think for this is that, by controlling where the motor sits they can put a a bigger, powerful and efficient motor.
Another detail which struck me was how can a very reactive chemical be used for structural integrity? Are they using the requirements for containment of the lithium as being useful for general crash worthiness? I find this similar to saying that the gasoline tank is a structural element in a car.
Regardless, interesting article!
(Score: 4, Interesting) by Anonymous Coward on Saturday June 09 2018, @02:11PM (6 children)
> I thought the future of electric was going to be in-hub motors...
The allure of hub motors is packaging space, but that is not the full story. The ratio of unsprung weight (tire/wheel/hub/suspension_parts) to sprung weight (the rest of the vehicle) is fundamental to good road holding -- where this is defined as maintaining a roughly constant force between tire and road. Of course there are many other contributing factors, but (at high speed) adding the mass of an in-hub motor would make any vehicle skittish on rough roads, particularly one as fast as this Jag.
From the suspension designer's point of view, the styling trend to large diameter wheels is bad enough--they weigh considerably more than "traditional" wheels of 13" to 15" diameter. When the "dubs" aftermarket fad started (22" wheels) some years back, there were reports of suspension and suspension-mount (body/frame structure) failures in vehicles that had not been designed for or tested with such heavy wheels and/or such low-aspect-ratio vertically-stiff tires. It took a few years for the manufacturers to catch on and design for the increased loads.
There have been many prototype "city cars" build with hub motors and they are probably OK for city speeds. Just don't expect them to be good on a rough freeway.
> ... with the differential electronically controlled
It's a safety thing--if an electronic diff fails, the car can become one wheel drive (or other asymmetric situations with all wheel drive). Since all the wheels are offset from the centerline of the car, additional drive force at any one wheel will tend to steer the car, sometimes violently. A normal "open" differential is inherently safe in this respect since it splits torque nearly evenly between the two outputs. Of course there are edge cases that can cause other problems (drive will be lost with one wheel on ice or lifted off the ground) but these are inconveniences, not an instant spin-out.
Electronic diffs offer a lot of control, with a new vehicle. Around here we have a lot of salt on winter roads and the idea of relying on electronics for a safety critical function, in a wet salty environment, is not something that I would consider buying. For the long term I'll take good old high strength steel (in the diff) over silicon (computer and power electronics) and insulated wiring.
(Score: 2) by Arik on Saturday June 09 2018, @03:50PM (5 children)
Which is exactly why I had expected something a bit more sophisticated than simply sticking the wheel in the hub, but retaining the concept of independent engines for each wheel. It seems to me that if you put the engine at the other end of a short shaft, just a shaft with no gears or other complications, just to put a little distance between it and the wheel, then mount this assembly to the suspension in between the two correctly; you could actually tune your effective ratio by shifting the attachment point one way or the other just a touch, and your 'drivetrain' of 4 quite short and simple shafts should still be considerably lighter and easier to construct than a conventional drive train. Thought there was a name for this design but I can't seem to remember it or rediscover it quickly.
"Electronic diffs offer a lot of control, with a new vehicle. Around here we have a lot of salt on winter roads and the idea of relying on electronics for a safety critical function, in a wet salty environment, is not something that I would consider buying. For the long term I'll take good old high strength steel (in the diff) over silicon (computer and power electronics) and insulated wiring."
I take your point there, but the strong trend in industry seems to be to ignore folks like us. And IIRC Subaru AWD has been computer controlled for a long time, in terms of transmission and differential it's all automatic and it's all computer controlled and it works well. As long as it stays isolated and doesn't wind up getting integrated into the entertainment system or rewritten in css or something, it should be possible to adapt that sort of system to 4 independent motor packages driving 4 independent wheels and see it work just as well, no?
I am not an automotive engineer.
If laughter is the best medicine, who are the best doctors?
(Score: 1, Interesting) by Anonymous Coward on Saturday June 09 2018, @04:05PM (1 child)
> It seems to me that if you put the engine at the other end of a short shaft, just a shaft with no gears or other complications,
As a minimum it's going to need a constant velocity (CV) joint at the wheel for steering and reasonable suspension geometry. For a non-steered (rear) wheel there is swing axle suspension (Beetle, Corvair, etc) that has no outer joints, but expectations for handling have gone beyond swing axles...
> IIRC Subaru AWD has been computer controlled for a long time
Audi, Subaru and many others have used electric/electronically controlled diffs for quite awhile. I believe that these generally (don't know about every kind) default to a reasonable passive system *when* the electronics fails.
(Score: 3, Interesting) by Arik on Saturday June 09 2018, @05:45PM
Well yes, correct, I should have been less categorical, let's say *minimum* of gears and other complications, obviously there has to be a linkage to let the shaft change attitude without tilting the wheel and vice versa, but that's something every (modern) car has regardless if I'm not badly mistaken here. I looked up swing-axle and this is nothing like what I am thinking of. It would basically be a wishbone suspension, well I guess it really would be a wishbone suspension, because what would change is only the bit that's carrying the power, not the suspension itself.
Reading back on that, I'm sure my wording is confusing and that's not entirely unrelated to the writer being a bit confused as well. But the basic point I'm trying to make is that four engines per wheel does not require actually mounting in the hubcap to eliminate a lot of heavy gear, just mounting them closer to the wheel would still eliminate a lot of heavy and expensive gear. You can even tune the weight-distribution by moving them in or out slightly, even if the way I described it initially was confused. And since it's going to be computer controlled either way, whether with a central powerplant and drivetrain or separate powerplants, that doesn't seem like a good objection.
"Audi, Subaru and many others have used electric/electronically controlled diffs for quite awhile. I believe that these generally (don't know about every kind) default to a reasonable passive system *when* the electronics fails."
I mentioned Subaru because it's the one I have a lot of experience with. It's always worked very well for me and I'm not aware of any major problems with it. I was skeptical when they went to that - I LIKED my fully manual Subaru I learned to drive on that car and I knew I could trust it. But the new transmissions have earned respect, they have always worked quite well for me.
Of course when I say 'new' transmission that's all relative, I haven't drive a truly recent one. For all I know they have finally rewritten it in javascript as a webapp running through the entertainment system already.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by Runaway1956 on Saturday June 09 2018, @05:17PM (2 children)
I can't say that I've seen you write a lot of silly stuff. But, you've screwed things up this time.
Javascript, man. You may choose between Chrome/Chromium, or Mozilla, but it's going to be javascript, either way. Javascript is the future!
(Score: 3, Funny) by Arik on Saturday June 09 2018, @05:47PM
If laughter is the best medicine, who are the best doctors?
(Score: 2) by MostCynical on Saturday June 09 2018, @09:45PM
differential need oil change and virus removal!
"I guess once you start doubting, there's no end to it." -Batou, Ghost in the Shell: Stand Alone Complex
(Score: 4, Interesting) by ledow on Saturday June 09 2018, @02:30PM (8 children)
Electric cars are nothing special either.
For most of the 60's/70's/80's, any British child would be woken in the morning by the whine of the electrically-powered "milk float" with its cargo of bottles tinkling down the road at 4am.
Entire towns, short stop, single-purpose (morning delivery, afternoon charging) electric vehicles. A bank of lead-acid under the hood, no transmission, almost dodgem-like controls (an "on/off" foot pedal that was more like a button), road-legal. Not huge great hulking things, not fast (famed for not being fast, but could do 30mph easily because that's all you want on an open-back vehicle carrying milk and eggs), but there.
Suddenly, 50 years later, there's a fuss about electric vehicles, almost appearing out of the blue 20+ years after they died out on the roads as a reliable and iconic symbol of good electric vehicle use. No better usage of a electric vehicle that takes hours to charge, doesn't have to do long journeys, and doesn't need to be complicated.
The fact that NOBODY bothered to anything with the technology between the 60's and 90's, and nothing for almost 20 years after that when they basically disappeared, tells you that we really have little interest in them. It's not that the technology wasn't there. It's that nobody cared. Suddenly, we care - despite the fact that the reason we care is supposedly "environmental" nowadays. It's not, it's to do with being different.
To be honest, to British eyes, the Tesla is nothing more than a glorified milk float, technology wise, with some ridiculous self-driving shite tacked on. Maybe a proper electric Jag could change that.
(Score: 2) by Immerman on Saturday June 09 2018, @03:15PM (2 children)
Heck, electric cars predate the internal combustion engine. *All* early cars were electric, though the much greater range of ICE vehicles helped them swiftly dominate the market. And by the time Ford's Model T started bringing cars to the masses, electric had become nothing more than a footnote. (actually... there were a few steam-powered cars early on, not sure how they fit in though)
What has changed about electric is the details - the invention of AC motors dramatically improved efficiency while lowering maintenance, while modern electronic control systems make it possible to vary their speed (or use brushless DC motors), and much lighter, higher capacity batteries gave them the range to be "good enough" for many modern drivers acclimated to ICEs. And of course the falling prices of those batteries has started making the whole shebang economically viable in a world that has developed around the range of ICE vehicles. As someone said decades ago "There's nothing wrong with electric cars that a battery with twice the capacity for half the price wouldn't solve". We're still not there yet, but it's improved to the point that they're at least becoming viable as luxury novelties.
(Score: 0) by Anonymous Coward on Saturday June 09 2018, @03:36PM (1 child)
> *All* early cars were electric
Citation needed.
https://en.wikipedia.org/wiki/Benz_Patent-Motorwagen [wikipedia.org]
> The Benz Patent-Motorwagen ("patent motorcar"), built in 1885, is sometimes regarded as the world's first 'production' automobile,[1] that is, a vehicle designed to be propelled by an internal combustion engine. The original cost of the vehicle in 1885 was 600 imperial German marks,[2] approximately 150 US dollars (equivalent to $4,086 in 2017).
>...
> Benz unveiled his invention to the public on 3 July 1886, on the Ringstrasse in Mannheim.
>
> About 25 Patent-Motorwagens were built between 1886 and 1893.
(Score: 2) by Immerman on Saturday June 09 2018, @07:59PM
First (model) electric car: 1828. They didn't start becoming practical until the invention of the lead-acid battery in 1859
"English inventor Thomas Parker, ... , built the first production electric car in London in 1884"
https://en.wikipedia.org/wiki/History_of_the_electric_vehicle [wikipedia.org]
(Score: 2) by Runaway1956 on Saturday June 09 2018, @05:25PM (3 children)
I would presume that Jaguar will have some expertise in the applications of magic smoke. US companies never really got it right, IMO.
http://www3.telus.net/bc_triumph_registry/smoke.htm [telus.net]
(Score: 0) by Anonymous Coward on Saturday June 09 2018, @05:44PM
Maybe once they knew about the prince of darkness (Lucas)...but it is a new day at Jaguar Land Rover. Now owned by Tata Motors, part of the giant Indian Tata Group.
(Score: 2) by frojack on Saturday June 09 2018, @09:00PM (1 child)
Jaguar is owned by Mumbai-based Tata Motors. Any edge in technology or quality that they ever had was lost when it was sold to Ford, who then pawned it off on Tata after ruining the brand and raping it of intellectual property.
I'm not sure Tata has the moxie to make this work on any grand scale. While they did restore some of the quality in Jaguar that Ford had ruined, the future is not that clear. [fool.com]
For many years, Tata manufactured cars that could not be sold anywhere on earth except India because they were simply dangerous. Jaguar was intended to be their quality play. But they are years behind the other big players in EVs.
No, you are mistaken. I've always had this sig.
(Score: 1, Interesting) by Anonymous Coward on Saturday June 09 2018, @09:12PM
> Any edge in technology or quality that they ever had was lost when it was sold to Ford, ...
Beg to differ on this part of your rant -- before Ford and its corporate quality edicts, Jaguar quality was terrible.
imo, the one dumb thing that Ford did was to make a lower cost Jag that was based on a Ford platform. It might have made some money, but didn't help the Jaguar image at all.
The sale to Tata was under the gun of the recession,
https://www.birminghampost.co.uk/business/business-news/jlr-would-ruined-ford-says-7398872 [birminghampost.co.uk]
Jaguar was bleeding badly and Ford didn't have the cash to keep it going, along with the main Ford operations. Remember that Ford didn't take US Gov't bail out money, but they did sell off a lot of assets to survive.
(Score: 2) by Phoenix666 on Sunday June 10 2018, @01:25PM
That portrayal is quite distant from the experience of driving modern EVs. I've driven Teslas, the Nissan Leaf, and BMW i3's. All of them deliver a superior driving experience to gas cars. First, the acceleration is instant, linear, and precise. That makes changing lanes, merging, and generally maneuvering on the road so much easier. Second, they're quiet. You can have a conversation or listen to your music at less than deafening levels.
Washington DC delenda est.
(Score: 2) by rleigh on Saturday June 09 2018, @07:51PM
We didn't have brushless DC motors back then.
(Score: 3, Interesting) by Immerman on Saturday June 09 2018, @08:11PM (1 child)
> how can a very reactive chemical be used for structural integrity?
I suspect you're right about the protective battery *case* being the structural component. However, I don't think there's any fundamental reason why the more volatile components of a battery couldn't be structural - chemical volatility and structural stability are rather independent variables. For example, if lead weren't so soft, you could use the electrode plates in a lead-acid battery for structural strength.
Of course, the trend seems to be towards using the minimum amount of material possible for electrodes, electrolyte, etc. Which makes sense - why waste material on the inside of the electrode, when only the surface is actually important to the functioning of the battery. But anything that reacts chemically is going to tend to change dimensions when it does so, which rather complicates using it for structural purposes.
(Score: 1, Informative) by Anonymous Coward on Sunday June 10 2018, @12:57AM
(Score: 2) by frojack on Saturday June 09 2018, @08:51PM
In hub motors proved to be very shock (impact) sensitive as various military organizations found out when deploying them.
Hub motors are still heavy, and being un-sprung weight they take a beating, and beat up the tires, and they are subject to water and
difficult to seal with any long-lived integrity.
So a short lateral drive shaft is still the best option.
No, you are mistaken. I've always had this sig.