Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster(bloomberg.com)
bloomberg.com
Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster
http://www.bloomberg.com/news/articles/2016-11-16/tesla-easter-egg-makes-the-world-s-fastest-car-even-faster
120 comments
Most jurisdictions call unsafely accelerating reckless driving or street racing. I own a car that will legitimately do 200 MPH but existing laws cover it too.
Top speed is a different beast altogether than acceleration, and I doubt you drive 200mph on public streets.
certainly not 200mph, but he i'm betting he breaks the speed limit. should we ban cars that go above 65mph?
on second thought, never mind, i probably know your answer.
"ban everything dangerous until there's no possible way anyone can get hurt" is not what freedom is.
on second thought, never mind, i probably know your answer.
"ban everything dangerous until there's no possible way anyone can get hurt" is not what freedom is.
should people have freedom to drive however they want, on roads used by plenty of other people too?
that seems like a good way to increase road fatalities
that seems like a good way to increase road fatalities
it's already illegal to do what you're describing. let me repeat that, for effect: already. illegal. it's against the law. you will literally be arrested and go to jail if you do that.
but don't let that stop you from passing 20 more laws, and then banning people from driving altogether after you realize that, as it turns out, criminals don't follow the law.
which is already happening, just look at the autonomous driving effort. which i'm sure makes you very happy. soon, nobody will drive, we will all be living in a perfect harmonious utopia of robotic sentience.
but don't let that stop you from passing 20 more laws, and then banning people from driving altogether after you realize that, as it turns out, criminals don't follow the law.
which is already happening, just look at the autonomous driving effort. which i'm sure makes you very happy. soon, nobody will drive, we will all be living in a perfect harmonious utopia of robotic sentience.
what are you arguing against then? no body even came near the topic of banning cars, other than you?
Unthought, kneejerk reaction.
Driving while eating a cup noodles is extremely dangerous too, I don't see any laws on the books against that.
Driving while eating a cup noodles is extremely dangerous too, I don't see any laws on the books against that.
Cars that can go this fast or close enough have been around for decades.
Indeed. But people who own supercars and other kit cars capable of such feats were rare and expensive.
Electric vehicles are going to take something, once rare, and make it common. Once it becomes common, the accident incidents will be more than just statistical noise, and legislative action may follow.
The NHTSA and FMCSA are currently working on a proposal for large commercial vehicles that would artificially limit their maximum speed to 68 mph. So it isn't unheard of for legislation to be created to target new vehicles which aims to improve public safety.
Electric vehicles are going to take something, once rare, and make it common. Once it becomes common, the accident incidents will be more than just statistical noise, and legislative action may follow.
The NHTSA and FMCSA are currently working on a proposal for large commercial vehicles that would artificially limit their maximum speed to 68 mph. So it isn't unheard of for legislation to be created to target new vehicles which aims to improve public safety.
The point is not that they're more common. Anyone that has wanted a fast car in the last 60 years could either buy or build one. Even a regular old car is plenty enough to kill yourself and plenty of other people if you're reckless enough. Besides that, it's much easier to create a stupidly dangerous car through sheer neglect of tires/brakes than to actually buy one that way.
Your argument is comparable to banning sharp knives because someone started selling them cheaper than butter knives. Both types have always been sufficiently available and dangerous that making one more common than the other isn't going to change anything
Your argument is comparable to banning sharp knives because someone started selling them cheaper than butter knives. Both types have always been sufficiently available and dangerous that making one more common than the other isn't going to change anything
sigh. knee-jerk reaction to ban dangerous things.
first of all, a minivan can kill you doing 10mph.
second, cars with this much power (and more importantly, top speed), have been around for a long time. you can build an 8-second quarter mile car in your garage and drive it on the street.
more nanny-state nonsense. "think of the children".
first of all, a minivan can kill you doing 10mph.
second, cars with this much power (and more importantly, top speed), have been around for a long time. you can build an 8-second quarter mile car in your garage and drive it on the street.
more nanny-state nonsense. "think of the children".
That "nanny state nonsense" witnessed road deaths fall from 25 per 100K in 1930 to 10 per 100K since 2010. We've halved road deaths per every 100K of population! I'll take my nanny state nonsense where people are still alive, over the libertarian wet dream where they're dead.
I really think it boils down to that some people value their own personal enjoyment over other people's safety. The sad truth is that you could absolutely enjoy vehicles like that but without endangering safety, by going to a race track. There's literally race days even for road-legal vehicles.
I really think it boils down to that some people value their own personal enjoyment over other people's safety. The sad truth is that you could absolutely enjoy vehicles like that but without endangering safety, by going to a race track. There's literally race days even for road-legal vehicles.
> That "nanny state nonsense" witnessed road deaths fall from 25 per 100K in 1930 to 10 per 100K since 2010
I think the better metric is the number of deaths per billion vehicle-km. In your metric most European countries have half the deaths than the US, but it's mostly explained by the fact that we drive less. I guess people had fewer cars and drove less in the 1930…
EDIT:
I found the stats: in 1930 you had 15.12 deaths per 100 million miles vehicle, in 2014 1.08. So the reduction is not 2.5x, but 15x!
I think the better metric is the number of deaths per billion vehicle-km. In your metric most European countries have half the deaths than the US, but it's mostly explained by the fact that we drive less. I guess people had fewer cars and drove less in the 1930…
EDIT:
I found the stats: in 1930 you had 15.12 deaths per 100 million miles vehicle, in 2014 1.08. So the reduction is not 2.5x, but 15x!
> I'll take my nanny state nonsense where people are still alive, over the libertarian wet dream where they're dead.
Don't assume that everybody will.
Don't assume that everybody will.
Your reasoning is extremely flawed. We have fewer deaths on the road because we added safety features and have road features designed to address what caused accidents in the past. Newer cars have way more horsepower and acceleration than in the past, yet deaths have gone down. You are arguing for something different, arbitrarily restricting acceleration.
Uhh... I'm pretty sure vehicle safety improvements have more to do with that than anything.
And obviously we all drive much much faster on average than people did in the 1930s, yet we are much much safer.
Which are enacted largely through legislation.
Crumple zones, seat belts, and air bags are a far cry from setting hard limits on performance characteristics of the vehicle, even if those same requirements may have had a negligible impact on vehicle performance.
I guess the question is where the line is drawn between sensible and "nanny-state" regulation.
I guess the question is where the line is drawn between sensible and "nanny-state" regulation.
to me, the rule of thumb is: does this regulation encourage innovation, or curtail it? it isn't black or white, but i think it brings it into focus a bit more.
But isn't banning top velocity on the manufacturer-level much more lower-hanging fruit than banning top acceleration? Just make it so your vehicle can't even go over legal speed limit. It should be clearer to us today how speed kills in some of the most wide-reaching ways.
Velocity is a much more obvious policy knob to tune for the goal of less vehicular deaths and injuries.
Velocity is a much more obvious policy knob to tune for the goal of less vehicular deaths and injuries.
Not being able to go over the legal speed limit can be dangerous (e.g. if the other cars on the road are, and you're not, you could actually be driving relatively slowly enough that it's unsafe, and you can even technically get a ticket for that under the right circumstances).
Similarly, in most places, speed limits are actually a little lower than they would be in the ideal world where everybody obeys them, to account for the fact that most people actually go a bit over the speed limit. And there are still highways that have absurdly slow speed limits that date back to the 1973 oil crisis (federal law set a maximum speed limit of 55mph, and not all highways have recovered from that yet).
Similarly, in most places, speed limits are actually a little lower than they would be in the ideal world where everybody obeys them, to account for the fact that most people actually go a bit over the speed limit. And there are still highways that have absurdly slow speed limits that date back to the 1973 oil crisis (federal law set a maximum speed limit of 55mph, and not all highways have recovered from that yet).
That's incredible. I don't think anyone will say electric cars are slow again!
Not sure I agree with the terminology of the article (fast rather than quickest accelerating), but I thought this quote was special:
> Speeds like this offer more Gs than Earth, so the rate of acceleration is faster than falling. It can feel difficult to support your head and shoulders if you don’t lean back on the headrest.
> Speeds like this offer more Gs than Earth, so the rate of acceleration is faster than falling. It can feel difficult to support your head and shoulders if you don’t lean back on the headrest.
1 g is nothing.
"A hard slap on the face may impose hundreds of g-s locally"
"Early experiments showed that untrained humans were able to tolerate 17 g eyeballs-in (compared to 12 g eyeballs-out) for several minutes without loss of consciousness or apparent long-term harm" https://en.m.wikipedia.org/wiki/High-G_training
"A hard slap on the face may impose hundreds of g-s locally"
"Early experiments showed that untrained humans were able to tolerate 17 g eyeballs-in (compared to 12 g eyeballs-out) for several minutes without loss of consciousness or apparent long-term harm" https://en.m.wikipedia.org/wiki/High-G_training
from the paper(o) in citation 3 from the linked wiki article(i):
> The terms "eyeballs in" "eyeballs out," and "eyeballs down" correspond to acceleration fields AX, -Ax, and AN, respectively, where AX, -Ax, and AN refer to the direction of acceleration forces measured in the conventional airplane body-axis coordinate system.
> AN acceleration factor, ratio of acceleration force to weight, positive when directed upward along spinal axis (i.e., from seat to head )
> AX acceleration factor, ratio of acceleration force to weight_ positive when directed forward transverse to spinal axis (i.e., from back to chest)
(o) https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/199802...
(i) https://en.m.wikipedia.org/wiki/High-G_training
> The terms "eyeballs in" "eyeballs out," and "eyeballs down" correspond to acceleration fields AX, -Ax, and AN, respectively, where AX, -Ax, and AN refer to the direction of acceleration forces measured in the conventional airplane body-axis coordinate system.
> AN acceleration factor, ratio of acceleration force to weight, positive when directed upward along spinal axis (i.e., from seat to head )
> AX acceleration factor, ratio of acceleration force to weight_ positive when directed forward transverse to spinal axis (i.e., from back to chest)
(o) https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/199802...
(i) https://en.m.wikipedia.org/wiki/High-G_training
At 2.6-sh second mark your car accelerates with more than 9.8m/s^2 to get to 60.
But even lower accelerations will glue you to the seat because gravity acceleration affects every part of your body. Where as the car grabs you by the butt and yanks you forward.
So - I think he has probably some vague idea of Newtonian physics but just didn't manage to produce coherent sentence.
But even lower accelerations will glue you to the seat because gravity acceleration affects every part of your body. Where as the car grabs you by the butt and yanks you forward.
So - I think he has probably some vague idea of Newtonian physics but just didn't manage to produce coherent sentence.
> But even lower accelerations will glue you to the seat because gravity acceleration affects every part of your body. Where as the car grabs you by the butt and yanks you forward.
The feeling of weight we associate with gravity is not distinguishable from elevator-style or car-style acceleration (not counting vibrations; or tiny gradients in the field). You don't feel gravity gluing you to the ground, you feel the ground continuously shoving you skyward to stop the free fall.
See: equivalence principle https://en.wikipedia.org/wiki/Equivalence_principle
The feeling of weight we associate with gravity is not distinguishable from elevator-style or car-style acceleration (not counting vibrations; or tiny gradients in the field). You don't feel gravity gluing you to the ground, you feel the ground continuously shoving you skyward to stop the free fall.
See: equivalence principle https://en.wikipedia.org/wiki/Equivalence_principle
How is more than one g accelleration possible?
There is one g making the friction between the tyre and the road.
I think this is intuitively wrong for a vehicle with a gear wheel locked to geared track: the gears push against each other and acceleration would be possible even in a zero g environment. Now, cars don't have gear wheels, but I assume the same principle applies.
Edit - here's a more stringent discussion: http://physics.stackexchange.com/questions/75032/maximum-acc...
Edit - here's a more stringent discussion: http://physics.stackexchange.com/questions/75032/maximum-acc...
Cars can do more than 1G even without downforce. Sports car street tires commonly ~1.2g, race tires commonly ~1.5g+
High school friction is wrong.
Source: various of my cars (in the past, I just have lame hybrids now) and a g meter
High school friction is wrong.
Source: various of my cars (in the past, I just have lame hybrids now) and a g meter
> High school friction is wrong.
No, it's at least mostly correct. High school friction says
If it's failed you, it's failed in failing to mention that the tire-road interface can have a coefficient of friction greater than one, and in failing to mention that the normal force can be increased with aerodynamic downforce.
No, it's at least mostly correct. High school friction says
F = mu * W
If it's failed you, it's failed in failing to mention that the tire-road interface can have a coefficient of friction greater than one, and in failing to mention that the normal force can be increased with aerodynamic downforce.
High school physics tends to claim that the coefficient can't be greater than one.
Source: note all the people here who thought it couldn't be greater than one.
Source: note all the people here who thought it couldn't be greater than one.
How is that due to high school physics rather than naive intuition?
Mine never implied that, and I could have easily disproved it with the grippy pads on my giant calculator.
Because the coefficient of friction could be greater than 1. And the "sticking" force is proportional to the tire area. And the air pushes you down while you move.
As long as the torque is lower than friction you should be fine.
As long as the torque is lower than friction you should be fine.
There's only one answer to that: the Lotus 78.
https://en.m.wikipedia.org/wiki/Lotus_78
https://en.m.wikipedia.org/wiki/Lotus_78
I don't understand the question. The car is accelerating horizontally, the gravity acts vertically.
The cars also gets pressed down by aerodynamics.
But downforce isn't appreciable until over 50mph (80kph), short of having stupidly oversized wings (which would drastically slow your acceleration) or active downforce (fans etc).
This is actually why a lot of expensive sports cars have 0-60 times of 2.9 seconds. Unless you design specifically for it, it's difficult to generate much downforce at low speeds.
Related: if you've ever wondered why some drag cars (e.g. Funny cars) have short exhaust pipes angled up and back, now you know.
Related: if you've ever wondered why some drag cars (e.g. Funny cars) have short exhaust pipes angled up and back, now you know.
Similar to the Red Bull F1 car's exhaust-blown diffuser: http://jalopnik.com/5892403/the-exhaust-pipe-that-made-red-b...
Imagine the tires were velcro'd to the ground. Or that they had giant spikes stabbing down for traction. Clearly you could go over 1g with that, right?
The same kind of thing (not literally, but analogously) is already happening at the atomic level, giving the tires a coefficient of friction of more than 1.
The same kind of thing (not literally, but analogously) is already happening at the atomic level, giving the tires a coefficient of friction of more than 1.
Indeed. My weak Google-fu indicates that the coefficient of friction of tyres against a dry road surface is something like 0.9, so there must be some improvement in tyre technology here just to make the thing go without creating a thick black smelly line on the road.
A car doesn't drag along the road. The tyres are in relatively static contact (unless you're drifting etc.). Static and dynamic friction are quite different.
As an aside: Spinning-rust hard drives are rated in the hundreds of Gs. While the earth only pulls with 1G, if you drop the drive onto a hard surface, the sudden stop is an acceleration of hundreds of Gs, due to the very short time frame.
Acceleration of more than 1g is probably not possible for 0-60; there isn't much of that speed range that would allow for downforce (downforce would only start have a tangible effect after approximately 50mph (80kph)), and there is no other appreciable way for the car to generate more friction with the road that doesn't scale with vehicle mass.
I suspect what the OP was trying to get at is the vector addition of gravity plus the forward acceleration of the car means that the apparent scalar force feels substantially higher than normal (i.e. 1g downwards); it's just poorly worded.
I suspect what the OP was trying to get at is the vector addition of gravity plus the forward acceleration of the car means that the apparent scalar force feels substantially higher than normal (i.e. 1g downwards); it's just poorly worded.
No they actually mean what they write - 1g gives you 0-60 in 60*1609/3600/9.81 = 2.73 seconds. The way to get that friction is probably to use a particular combination of tires and road. It's equivalent to standing still on a 45 degree slope -- not impossible, but definitely a risk of slipping there.
but there is four tires!
and 4/4ths of a car
With rear-wheel drive, acceleration transfers most of the vehicle weight to the rear wheels. That's why funny cars do wheelies. That doesn't work so well for front-wheel drive, so those vehicles can't accelerate as quickly as rear-wheel drive vehicles. With four-wheel drive, weight transfer cuts both ways, but more rubber on the road helps, for sure. Low center of gravity helps too, I think.
right-left-brake-right-left-gas-left-gas-right-brake-right-left-gas-brake-brake-left
Is it still called the "gas" pedal on an electric car?
You mean "gas-gas-brake-brake-left-right-left-right-lights-radio-eject"?
"Gas, Brake, Honk. Gas, Brake, Honk. Honk, Honk, Punch."
You need to tell "Power Overwhelming" to the car
At what battery percentage? Let alone, why? I want range, range, and more range. I could not give a damn about how fast I get to the next stop light or supercharger. Brag when you get 500 miles a charge, even fifty miles more range is more impressive than a tenth of a second off your acceleration "with a full charge"
> I want range, range, and more range. I could not give a damn about how fast I get to the next stop light or supercharger.
You're not the target audience for their top-of-the-line P100D. It's aimed at people who would otherwise buy Bugatti Veyrons, Ferraris, etc., and range probably doesn't even come up in their decision making process. The Veyron has a range of 50 miles at top speed, for example.
You're not the target audience for their top-of-the-line P100D. It's aimed at people who would otherwise buy Bugatti Veyrons, Ferraris, etc., and range probably doesn't even come up in their decision making process. The Veyron has a range of 50 miles at top speed, for example.
No... it's not.
People in the market for supercars at up to $2MM are not in the same market as the P100D.
Range may not come up as an issue, as you say with the Veyron. The fact that the Veyron can actually accomplish it's top speed for those 50 miles will, however. Just like Tesla cannot complete a lap of a race course at top speed without thermal shutdown / limiting.
People in the market for supercars at up to $2MM are not in the same market as the P100D.
Range may not come up as an issue, as you say with the Veyron. The fact that the Veyron can actually accomplish it's top speed for those 50 miles will, however. Just like Tesla cannot complete a lap of a race course at top speed without thermal shutdown / limiting.
And that's about the range of the tires at top speed as well.
"aimed at people who would otherwise buy Bugatti Veyrons, Ferraris"
More like Porsche 911 Turbo, Mercedes SLS, Audi R8 buyers.
More like Porsche 911 Turbo, Mercedes SLS, Audi R8 buyers.
No, I think more like Dodge Charger Hellcat buyers. Those who pony up for a 911, SLS or R8 want a car that'll go faster around the Nürburgring than a Honda Civic Type R. Which I think even the P100D won't be able to (too heavy, brakes and motors overheat).
Edit: why the downvotes? It's well documented that the P90D is no quicker than a Civic Type R around a proper racetrack.
Edit: why the downvotes? It's well documented that the P90D is no quicker than a Civic Type R around a proper racetrack.
I think the P90D/P100D buyers are not the types to necessarily by a Charger or Challenger. They're fun cars but a bit louder... just got a 2016 392 Scat Pack Shaker Challenger a few months ago, very fun car... but not in any way similar to any Tesla. It's just a different feel.
That said, most aren't in a position to really push their cars, and they don't... It's mostly bragging and any car with a 0-60 under 5 seconds will give a lot of that fun.
That said, most aren't in a position to really push their cars, and they don't... It's mostly bragging and any car with a 0-60 under 5 seconds will give a lot of that fun.
You're not thinking of the right social category of buyers.
The people buying Veyrons are doing it for status. They're not going to replace their >$2 million car with one <$2 hundred thousands.
The people buying Veyrons are doing it for status. They're not going to replace their >$2 million car with one <$2 hundred thousands.
> The Veyron has a range of 50 miles at top speed, for example.
That top speed being 250mph. Who drives 50 miles at 250mph? And where do they do it?
And, more importantly, they can refill in the blink of an eye and travel 50 more.
That top speed being 250mph. Who drives 50 miles at 250mph? And where do they do it?
And, more importantly, they can refill in the blink of an eye and travel 50 more.
Well, if you have to refuel every eight minutes, then the time to fill up becomes quite relevant. Not to mention that the main problem will be tyres, as those likely won't do a whole lot of miles at such speeds. Qoute: "In testing Michelin had run the Veyron’s massive meats on its tire dyno at 270 mph — the fastest it can spin — for 20 seconds, then at 250 mph for 20 seconds. It repeated that cycle two more times. Then the tires exploded." http://www.motortrend.com/news/bugatti-veyron-grand-sport-vi...
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The tires also cost tens of thousands of dollars. The wheels need to be replaced fairly frequently as well, and they also cost tens of thousands of dollars. Supposedly there are Veyron owners who ship their car to a destination and then follow along in their private jet because that's cheaper than driving the car there. The P100D isn't cheap, but the Veyron is a whole different category of expensive.
There's a lot of cars that are like that. Cost in Fuel, Miles and general depreciation. Just ship it. Its not that crazy.
Also if anyone wants to see someone do a full on heavy run of the Veyron check out Ben on Goldrush 2015? He ran his I think to 255mph if memory serves me right...
Also if anyone wants to see someone do a full on heavy run of the Veyron check out Ben on Goldrush 2015? He ran his I think to 255mph if memory serves me right...
What's crazy about the Veyron isn't that it's cheaper to ship it than to drive it. It's that it's cheaper to ship it and fly there on your private jet than to drive it. Your car needs to be pretty expensive to operate for that to be a net win.
Maybe there are still "a lot" of cars like that in the realm of million-dollar supercars. But I think it qualifies as crazy when the context is a family sedan that's fairly cheap to operate.
Maybe there are still "a lot" of cars like that in the realm of million-dollar supercars. But I think it qualifies as crazy when the context is a family sedan that's fairly cheap to operate.
James May only goes 30 miles. On a closed track... https://www.youtube.com/watch?v=LSFX9vrwJf8
You know Tesla has non-performance models too?
Is Tesla so fast compared to the price because is an electric car or this is totally unrelated and was just designed to have such an acceleration, without help from the fact it's an electric car? Thanks.
EDIT: Thank you for the replies!
EDIT: Thank you for the replies!
The reason why an EV would outperform most motors is mutli-fold
1. No cold starting. The engine is on as soon as you push power in.
2. Equal torque at all speeds
3. The lack of a need for a transmission. All "gears" can be controlled by how much power you're feeding
There's a 4th you're missing: lower reciprocating mass.
Low mass connected to the wheels(aside from the stator) combined with near instant torque control means they can adjust power to the wheels in a sub-ms(supposedly) range. Once you break traction it's really hard to get it back and you're fighting the momentum of an ICE engine in the non-EV case. You also have two completely independent motors so you don't have to fight with any transfer case or torque converter and it can just instantly shift power to where traction is available.
All I know is I can floor our 85D in the rain and it doesn't even shimmy, just plants and takes off.
Low mass connected to the wheels(aside from the stator) combined with near instant torque control means they can adjust power to the wheels in a sub-ms(supposedly) range. Once you break traction it's really hard to get it back and you're fighting the momentum of an ICE engine in the non-EV case. You also have two completely independent motors so you don't have to fight with any transfer case or torque converter and it can just instantly shift power to where traction is available.
All I know is I can floor our 85D in the rain and it doesn't even shimmy, just plants and takes off.
The fundamental explanation is that electric drivetrain's efficiency curve is rather flat, meaning that you can build a powerful drivetrain without sacrificing efficiency (= range in electric car).
With ICE, you have to choose either power or efficiency, i.e. the engine is tuned for specific load and the efficiency sacks when heavily under loaded. (Constant legal-speed driving makes only a fraction of load of heavy acceleration.)
With ICE, you have to choose either power or efficiency, i.e. the engine is tuned for specific load and the efficiency sacks when heavily under loaded. (Constant legal-speed driving makes only a fraction of load of heavy acceleration.)
The "cold starting" issue isn't as significant as it might seem. Most acceleration tests on ICE vehicles are started with the brakes down and the throttle up. It is very hard on the vehicle and doesn't match what you would likely do in the real world, but it does mean power is available right from the start.
It's not equal torque at all rpm.
So, torque is defined as Tau = P / omega where P is power, omega is angular velocity and Tau is torque. In an ICE, P varies a lot with rpm (i.e. angular velocity) giving a sort of inverse-bathtub curve whereas in an electric motor the power curve is pretty much flat. In an ICE at startup (so essentially zero plus epsilon rpm or angular velocity) the power is quite low, so torque is also low. In the electric motor the power output will be essentially whatever it is rated at, so the torque will be highest at this point, getting lower as rpm (angular velocity) increases.
For a much better explanation than I can provide, see https://en.wikipedia.org/wiki/Power_band#Electric_Motors
For a much better explanation than I can provide, see https://en.wikipedia.org/wiki/Power_band#Electric_Motors
Effectively it's more equal then an ICE.
Also if you can get someone who has a lot of experience with motor control they can get you going pretty quickly. I'm assuming what's in the Tesla is a brush-less DC motor and there are a few things you can do (especially since you're on some serious batteries in the Tesla) to push some serious torque at the startup curve. You're probably only running a modulated power start for a few seconds. After the first few seconds you're shoving the full amperage into the motor.
Also if you can get someone who has a lot of experience with motor control they can get you going pretty quickly. I'm assuming what's in the Tesla is a brush-less DC motor and there are a few things you can do (especially since you're on some serious batteries in the Tesla) to push some serious torque at the startup curve. You're probably only running a modulated power start for a few seconds. After the first few seconds you're shoving the full amperage into the motor.
As pointed out in other comments Tesla actually uses AC induction machines (asynchronous AC) instead of brushless machines (synchronous AC). To a first approximation an AC induction machine can produce constant torque up to a fixed speed. Above this speed the torque falls off as approximately 1/speed.
You are right about the startup torque. AC induction machines can produce full breakdown torque at zero speed, but this does require high current (but luckily not high power because the applied voltage is still low due to low motor speed).
Another limit is the junction temperature of the power semiconductors in the inverter(s). I think Tesla uses liquid cooled inverters, but this typically means there isn't much mass to act as a heatsink (relying on the liquid coolant instead), so overload times are typically very short. I'd would guess this is actually the limit in their design. In other words they can put very high currents into the motor for a long period of time before it thermally overheats, but way before that time they have to reduce the current in order to protect the power semiconductors in the inverter.
You are right about the startup torque. AC induction machines can produce full breakdown torque at zero speed, but this does require high current (but luckily not high power because the applied voltage is still low due to low motor speed).
Another limit is the junction temperature of the power semiconductors in the inverter(s). I think Tesla uses liquid cooled inverters, but this typically means there isn't much mass to act as a heatsink (relying on the liquid coolant instead), so overload times are typically very short. I'd would guess this is actually the limit in their design. In other words they can put very high currents into the motor for a long period of time before it thermally overheats, but way before that time they have to reduce the current in order to protect the power semiconductors in the inverter.
To my knowledge the essence of an electric engine is that is has max traction almost independent of the rpm. Where a petrol engine has an optimal rpm (4000 for instance) where it provides most power, the electric car does not. Consequence is that a petrol car needs a gearbox to keep the engine around this optimal RPM (and thus most power) while the electric engine does not need one - it accelerates and keeps on accelerating...
So the Tesla is so fast because it is electric, not because it has other features.
Max torque, not traction.
That, and being able to do all wheel drive efficiently and with less weight penalty and with less risk to drivetrain parts helps the quick acceleration.
But you still have to make tons of power and not be too heavy of course.
But you still have to make tons of power and not be too heavy of course.
Yes and no. While the grandparent post was clearly confusing traction and torque quite a bit, the answer is still mostly about traction.
At the supercar level, you can basically assume infinite power when looking at acceleration in the lower speed ranges. The limit is traction, not torque. A sufficiently strong EEV can continuously max out traction. An ICE supercar does the same, but with a few tiny gaps for shifting that add to the total time. The ICE supercars do not need a stronger engine to come closer to the Tesla, they need faster transmissions to minimize shifting gaps. I think that this is also the prime reason why manual transmissions are disappearing/have disappeared from supercar territory, dual clutch automatics provide shorter gaps.
At the supercar level, you can basically assume infinite power when looking at acceleration in the lower speed ranges. The limit is traction, not torque. A sufficiently strong EEV can continuously max out traction. An ICE supercar does the same, but with a few tiny gaps for shifting that add to the total time. The ICE supercars do not need a stronger engine to come closer to the Tesla, they need faster transmissions to minimize shifting gaps. I think that this is also the prime reason why manual transmissions are disappearing/have disappeared from supercar territory, dual clutch automatics provide shorter gaps.
Which is only partly right. Also electric drives have a dependency of torque to rpm(1).
But it is much more easy to control than an ICE.
(1): http://lancet.mit.edu/motors/motors3.html
(1): http://lancet.mit.edu/motors/motors3.html
It also depends on how you define "Worlds fastest car" While there is no doubt this is a fast car and that time is a stonking 0-60 time. I am lead to believe it can't complete a full flat out lap of the Nurburgring as constant high speed/full throttle use heats up the battery to the point where performance has to be limited.
So while it will be great to "hoon about" in and should be a win at the traffic light gran prix there are probably much better track day cars.
So while it will be great to "hoon about" in and should be a win at the traffic light gran prix there are probably much better track day cars.
> It also depends on how you define "Worlds fastest car"
... and here they defined it so the P100D is the fastest. Welcome to the tautology club.
Meanwhile, Wikipedia has three cars above the P100D on its quickest 0-60 list: the Porsche 918, the LaFerrari, and the Bugatti Veyron.
https://en.wikipedia.org/wiki/List_of_fastest_production_car...
Note also that Tesla has also been called a bit "optimistic" with their 0-60 times as compared to other manufacturers (e.g. by Top Gear when testing P90D against Audi RS6 this year).
... and here they defined it so the P100D is the fastest. Welcome to the tautology club.
Meanwhile, Wikipedia has three cars above the P100D on its quickest 0-60 list: the Porsche 918, the LaFerrari, and the Bugatti Veyron.
https://en.wikipedia.org/wiki/List_of_fastest_production_car...
Note also that Tesla has also been called a bit "optimistic" with their 0-60 times as compared to other manufacturers (e.g. by Top Gear when testing P90D against Audi RS6 this year).
Wikipedia still shows the old 0-60 time for the P100D. At 2.4 seconds, it will be ahead of the Veyron, even with the LaFerrari, and behind the 918.
And Tesla only compares with cars currently in production. The LaFerrari and 918 are not.
Definitely some definitional tweaking to get the "right answer," but not quite a tautology.
And Tesla only compares with cars currently in production. The LaFerrari and 918 are not.
Definitely some definitional tweaking to get the "right answer," but not quite a tautology.
"the old 0-60 time"
The _current_ 0-60 time, you mean. Especially with this:
"And Tesla only compares with cars currently in production."
considering this is only a teaser tweet, there's a slight hint of irony there. "Currently in production" is also very different from "fastest production cars". Very selective.
This happened last time Tesla announced something like this - people fell over themselves to install it in the Wikipedia page for fastest production cars. Even though it was: 1) not yet available, 2) not verified, and 3) described even by Tesla themselves as an "expected result". i.e. a press release.
When that didn't work, they took to the page to add a new column to the list of accepted results, to add, effectively "manufacturer projected results", with the end result looking entirely silly and forced - a top 20 chart with Tesla being the only one to have a result in a "not real, not yet" column.
The _current_ 0-60 time, you mean. Especially with this:
"And Tesla only compares with cars currently in production."
considering this is only a teaser tweet, there's a slight hint of irony there. "Currently in production" is also very different from "fastest production cars". Very selective.
This happened last time Tesla announced something like this - people fell over themselves to install it in the Wikipedia page for fastest production cars. Even though it was: 1) not yet available, 2) not verified, and 3) described even by Tesla themselves as an "expected result". i.e. a press release.
When that didn't work, they took to the page to add a new column to the list of accepted results, to add, effectively "manufacturer projected results", with the end result looking entirely silly and forced - a top 20 chart with Tesla being the only one to have a result in a "not real, not yet" column.
One of the meanings of "old" is "former or previous."
And I see no irony. The teaser tweet is stated using the future tense. It will be the fastest car in production once it comes, unless some other car maker has a big surprise between now and then.
As for the Wikipedia stuff, I offer no defense of it, but I'm not surprised. Wikipedia suffers from plenty of fanboyism.
And I see no irony. The teaser tweet is stated using the future tense. It will be the fastest car in production once it comes, unless some other car maker has a big surprise between now and then.
As for the Wikipedia stuff, I offer no defense of it, but I'm not surprised. Wikipedia suffers from plenty of fanboyism.
"We don't compare against cars not currently in production. Our car, not currently in production, is faster."
But it's not the biggest thing in the world. :)
But it's not the biggest thing in the world. :)
Replace "is" with "will be" and the strangeness goes away.
There's also the weird aspect that the car itself has been sold for months, they'll just become faster once the update hits.
There's also the weird aspect that the car itself has been sold for months, they'll just become faster once the update hits.
The first rule of Tautology Club is the first rule of Tautology Club
Car and Driver just compared another 20 or so cars at their resident Lightning Lap track a few months ago, including a Tesla. The Tesla was not fast, approx. 30 sec slower on a track that fast cars were finishing in the 2:45 range.
http://www.caranddriver.com/features/tesla-model-s-p85d-at-l...
http://www.caranddriver.com/flipbook/lightning-lap-2016-ever...
http://www.caranddriver.com/features/tesla-model-s-p85d-at-l...
http://www.caranddriver.com/flipbook/lightning-lap-2016-ever...
Acceleration is also relatively poor above about 100 MPH. It's an amazing beast, but yes certainly a traffic light car no sports car.
The fact is anything below 5 seconds 0-60 is a damned speedy car that you really won't get to push in day to day driving... As it is, I've been in a few Model S's and they are fun. I'll keep my Scat Pack Challenger though, far less expensive, only a second lower, and a higher top speed. Not to mention looking quite a bit cooler imho.
I guess the title is right if you don't have access to the German Autobahn...
https://www.youtube.com/watch?v=nF36JhHRm4I
https://www.youtube.com/watch?v=nF36JhHRm4I
Does anyone have an idea of what they did/could have done in terms of software to allow a performance improvement?
I have a guess: the limit in these designs isn't typically the motor, but instead the power semiconductors in the inverter (the motor has a much longer thermal time constant than the power devices). Therefore the limit is the junction temperature of the power devices. Most high performance drives have some kind of junction temperature estimation algorithm (it is difficult or impossible to put a sensor right at the junction without changing the electrical properties of the semiconductor). When the estimated temperature gets too high, they will start pulling back the current to protect the power devices from overheating. The more accurate the model, the closer they can push the devices to the limit without failure.
I'd bet they have been slowly improving their junction temp. estimation model and are now able to push the power semiconductors a little bit closer to their temperature limit, allowing them to produce more current (or the same current for a longer duration) before pulling back.
I'd bet they have been slowly improving their junction temp. estimation model and are now able to push the power semiconductors a little bit closer to their temperature limit, allowing them to produce more current (or the same current for a longer duration) before pulling back.
I've imagined Elon, still connected to childhood sci-fi dystopian futures, would most certainly include some secret "God Mode" backdoor that only he knows...
So, in a future where Tesla's are all over the roadways,and the earth falls under alien attack or some other crisis -- he could easily escape by speaking to any nearby Tesla, which would give him full access (maybe even unlocking faster speeds ;). Perhaps even having some sort of transponder to send the nearest Tesla's to his rescue, should that be required.
So, in a future where Tesla's are all over the roadways,and the earth falls under alien attack or some other crisis -- he could easily escape by speaking to any nearby Tesla, which would give him full access (maybe even unlocking faster speeds ;). Perhaps even having some sort of transponder to send the nearest Tesla's to his rescue, should that be required.
In the future where aliens land on Earth and start a ground assault[0], Elon can take all the Teslas left by fleeing civilians and use them as remotely controlled (soon to be autonomous) weapons to fight the invasion, all from the safety of his volcano lair. ;).
--
[0] - Why ground assault instead of orbital bombardment? Well, there aren't many alien vessels left in orbit after a massive onslaught of Falcon 9s and BFRs ;).
--
[0] - Why ground assault instead of orbital bombardment? Well, there aren't many alien vessels left in orbit after a massive onslaught of Falcon 9s and BFRs ;).
If I remember correctly, there is a scene in the book Daemon by Daniel Suarez where autonomous cars are used similarly.
wavefunction(4)
Zero to sixty in 2.5 seconds is fun, no doubt about it, but it is fun on a racetrack. You can go on YouTube right now and find dozens of people utilising Tesla's existing "ludicrous mode" on public streets.
And here's the thing, if people want to endanger their own lives that's fine. But they aren't just endangering their own lives, they're also endangering both other road users and pedestrians (when they eventually lose control).
I don't think anything has been done about this yet because Teslas are still pretty uncommon, and the features which unlock "ludicrous mode" are even more uncommon (like 1% of 1%). But once electric vehicles are the norm and the body count racks up, we'll see legislative action.
As an aside you could tie maximum acceleration into road conditions, including lowing it if the road is icy or wet, or increasing it on surfaces that provide superior grip (like freeways).