Chevy To Make Spark E.V

CiniO

CiniO wrote: »

Where is the torque and RPM you stated calculated?
On the exit from the electric motor, or after going through this reducing gear?
Because on all fuel and diesel engines it's calculated on the engine, so I assumed, it's the same with electric motors.

No Idea, I just go by the figures given for the different cars which I'm sure are calculated the same. So the Leaf has 230 or so lbs torque, I would expect the Spark ev with 400 to accelerate with far more force.

CiniO wrote:

This again proves you have no clue what you are talking about.
Power of any engine at 0rpm will be 0. Nothing will change it.

Yes engine, but not electric motors. An engine has to take in air compress it and so on an electric motor doesn't and not only that a motor is 80+ % efficient compared to 25 or so % of an engine, so a 107 hp engine will not have the same power as an electric motor.

CiniO wrote: »

It is, as what you said above is not correct.
Power is a measure of the rate at which work is performed. At 0 rpm, there is no work performed at all.

Yes in an engine, an engine needs to spin at a few thousand rpm to produce enough torque a motor produces it all from 0 rpm.

CiniO wrote: »

Still not sure what you mean by that.
Voltage on batteries in EV is always the same.
There surely is control system which can adjust electric motor speed and cause accelerating.

More voltage means more rpm meaning the motor will spin faster meaning a faster top speed, dumping more current means more torque and it will accelerate faster, SO the final speed is not just determined by voltage alone but by gearing and software. There is a trade off in electrics where the high rpm of the motor is converted to low rpm for better efficiency at slow speeds resulting in a slower top speed. But you can increase the voltage more but would mean a bigger battery.

CiniO wrote: »

Combustion engine can't work below some RPM (usually around 700 - 800) and indeed its torque varies a lot through rpm range, while in electric motor torque is usually quite stable through all rpm range.
But what is has to do with things we are talking about?

Lost you here ? and I'm heading to bed but we can discuss this again tomorrow.

CiniO

Deleted User wrote: »

No Idea, I just go by the figures given for the different cars which I'm sure are calculated the same. So the Leaf has 230 or so lbs torque, I would expect the Spark ev with 400 to accelerate with far more force.

It's the power parameter that you need to look at, not torque.
Leaf AFAIK has 107 HP. Spark will have 130 HP. Assuming they are similar weight, most likely spark will be slightly faster.

Fact that Spark has nearly double the torque doesn't reveal any info without knowing the gear ratios, tyre sizes, etc.
But power in BHP is enough to know approximate performace rate for those cars.

Yes engine, but not electric motors.

I meant both. Sorry.

An engine has to take in air compress it and so on an electric motor doesn't and not only that a motor is 80+ % efficient compared to 25 or so % of an engine, so a 107 hp engine will not have the same power as an electric motor.

It will.
107 HP power is 107 HP power no matter if it's generated by combustion engine or electric motor, or anything else.

Yes in an engine, an engine needs to spin at a few thousand rpm to produce enough torque a motor produces it all from 0 rpm.

Torque - yes.
But I think you are forgetting (or are not aware of) that power = torque * revolutions.

So if revolutions are 0, then there can't be any power, no matter if we are talking about electric motor or engine.

More voltage means more rpm meaning the motor will spin faster meaning a faster top speed, dumping more current means more torque and it will accelerate faster, SO the final speed is not just determined by voltage alone but by gearing and software. There is a trade off in electrics where the high rpm of the motor is converted to low rpm for better efficiency at slow speeds resulting in a slower top speed. But you can increase the voltage more but would mean a bigger battery.

You can the same get 15,000rpm from 500volts as well as 1.5volts.
It all depends on electric motor.
Anyway - this voltage and currant talk has very little to do with rpm and torque.

Wheres My ForkandKnife

I'd say you two would be popular at parties:D.

However if that chevy farted €20 notes from the exhaust I wouldn't drive it as it's pig ugly.It make the prius look like a hot hatch.

However I am interested in the technology of the ev and the prius.Or at least I was until I read mad lads posts about them.The one on "learning to drive" them would put anyone to sleep.And when you tell a lad with a dpf problem to get a prius it borders on seeking help.

I get the whole fanboy thing about the prius and ev's but you take saving money to a whole new level.Following your logic I feel like hopping in the coffin now, when I think of all the money I'm wasting on food and other neccessities.Sure I won't be able to have a drink of water when the water charges come in:pac:

ARGINITE

CiniO wrote: »

Torque - yes.
But I think you are forgetting (or are not aware of) that power = torque * revolutions.

So if revolutions are 0, then there can't be any power, no matter if we are talking about electric motor or engine.

Ah I think I misread your quote, you are saying power and not torque.

Wheres My ForkandKnife

Wheres My ForkandKnife wrote: »

I'd say you two would be popular at parties:D.

However if that chevy farted €20 notes from the exhaust I wouldn't drive it as it's pig ugly.It make the prius look like a hot hatch.

However I am interested in the technology of the ev and the prius.Or at least I was until I read mad lads posts about them.The one on "learning to drive" them would put anyone to sleep.And when you tell a lad with a dpf problem to get a prius it borders on seeking help.

I get the whole fanboy thing about the prius and ev's but you take saving money to a whole new level.Following your logic I feel like hopping in the coffin now, when I think of all the money I'm wasting on food and other neccessities.Sure I won't be able to have a drink of water when the water charges come in:pac:

LOL that was funny,

Hey I didn't get the Prius for the (main) reasons of saving money, people seem to misunderstand.

I got the Prius because while looking for another Diesel car to replace the A4 I just couldn't accept buying a diesel with 30-40K more miles on the clock at the time and for 3-4 grand more money. I got a good bargain on the Prius, so it would have been foolish not to have bought it.

I also wanted to own one because I'm a huge technology nut and one reason I enjoy driving the Prius, I also love driving the CRV. Which if they open a LPG station near buy I'll certainly be converting it and will cost similar to run as the Prius on petrol.

Anyway another reason for getting the Prius after was because of it's proven reliability and low enough maintenance.

The fact it's great on petrol for it's size and being automatic was a great benefit, and the lack of the rattle and noise of a diesel.

I can also say that with the miles we clock up the Prius is the most reliable vehicle I've owned by far.

So it's not just down to saving money on fuel.

CiniO

CiniO wrote: »

It's the power parameter that you need to look at, not torque.
Leaf AFAIK has 107 HP. Spark will have 130 HP. Assuming they are similar weight, most likely spark will be slightly faster.

The Spark will only be faster if GM allow it in the controller software.

CiniO wrote: »

Fact that Spark has nearly double the torque doesn't reveal any info without knowing the gear ratios, tyre sizes, etc.
But power in BHP is enough to know approximate performace rate for those cars.

Yes if you compare EV with EV.

Remember that an engine is rated at it's peak output usually high in the rev band, while a motor can produce it at mostly all of it, and also the motor converts more power a lot more efficiently so comparing the 2 isn't the same.

That's why the Leaf with only 107 HP feels very fast off the line.

CiniO wrote: »

107 HP power is 107 HP power no matter if it's generated by combustion engine or electric motor, or anything else.

Yes HP is HP but in the case of the electric car that HP can be used for more acceleration or more top speed, and so the top speed is limited in an e.v by software you can use that HP for more acceleration instead.

CiniO wrote: »

Torque - yes.
But I think you are forgetting (or are not aware of) that power = torque * revolutions.

So if revolutions are 0, then there can't be any power, no matter if we are talking about electric motor or engine.

You could have 0 rpm and no output to the wheels you mean ?

But you can have a stalled motor still producing power but that would be converted to heat very quickly.

That's why the motor in an e.v spins very fast because motors are a lot more efficient at high rpm and the need for the reducer gear because the wheels can't spin that fast. And another reason wheel hub motors are a challenge because output would be proportional to the rpm of the motor and so a very steep hill could cause over heating as the motor wouldn't be efficient at low rpm.

CiniO wrote: »

You can the same get 15,000rpm from 500volts as well as 1.5volts.
It all depends on electric motor.
Anyway - this voltage and currant talk has very little to do with rpm and torque.

Voltage and current do have a lot to do with torque Hp etc.

voltage x current = watts watts =power = torque = hp

Current gives more torque, voltage gives more speed to the motor, it's that simple, Kv of the motor and final gearing do matter also.

colm_mcm

I've seen prices of $25,000 after tax rebate and $32000 before guessed for this car. Isn't this more expensive than a leaf?

Matt Simis

ARGINITE wrote: »

Ah I think I misread your quote, you are saying power and not torque.

It doesnt matter, if the "power" discussed is horsepower for rotating objects and its not even moving, then it has no effective torque or power, it cannot be measured.
EDIT: Thats actually incorrect, you can have torque without movement but you cannot have power. Torque without movement is important for moving a stopped train.. not so much for a car.

horsepower = torque x revolutions per minute / 5,252.

400ft-lbs * 0rpm / 5252 = 0 power.

And, as Cino already said, 400ft-lbs peak torque with 130hp =
RPM formula = HP x 5,252 / torque
Spark EV = 130 x 5252 / 400 = 1706rpm at peak power.

All the relevant formulas wrote:

Horsepower = torque x RPM / 5,252
TORQUE FORMULA= T = HP x 5252 / RPM
RPM formula = HP x 5,252 / torque

Mad_Lad, I dont think its correct to state that there is some "difference" in Electric vs Combustion motors regarding stated power and torque. These are measurements, source of power doesnt matter. A 130hp EV would have the same peak power as a 130hp Passat TDI and with similar gearing and weight, pretty much the same performance. The aforementioned A6 3.0TDI produces 370ft-lbs of torque from 2200 to 3400 RPM (and I think there are faster versions of the engine), which is far more "power" than 400ft-lbs at 1700rpm (peak).

Its also not correct to state that Electric motors "go to 15000rpm" and have the same torque from near 0rpm, they dont on either account, they loose torque as RPM increases and they mostly do not rev anywhere near 15,000RPM in EV applications. There is also a significant difference between DC and AC motors, which in its own world is like comparing the merits of Petrol vs Diesel.


DC Motor for EVs:


AC Motor for EVs:

colm_mcm

colm_mcm wrote: »

I've seen prices of $25,000 after tax rebate and $32000 before guessed for this car. Isn't this more expensive than a leaf?

Probably make it around 25,500 Euros after Government rebate of 5,000 then you stick on a nice profitable 23% VAT, though that doesn't include import taxes or import duties ?

maybe it will be made in Europe ?

The Leaf currently cost €27,500 but they have cheaper options for the updated version along with battery rental options for the first time.

The Cheapest trim leaf will be available in the U.K for €18,750 without battery or rental starts at around 75 pounds or so a month up to 129 Pounds a month for 15,500 miles a year.

Someone on the Leaf UK forum stated that with the excess mileage charge it would actually work out a lot cheaper to rent at a lower package than you need and pay the excess.

You can also buy the battery.

Interestingly enough, if you buy the car with the battery it adds 5,000 pounds, so does that mean the battery costs 5,000 pounds ? if so that is a huge drop in the last 2 years alone.

So probably cost 2,000 for a new one by the time you need a new battery in 8-10 years.

If you fast charge all the time then you'd be better to lease, though they do state that fast charging multiple times a day every day will degrade the battery quicker and they might not cover that.

I don't think fast charging once a day for 10 mins or so would have a bad effect.

ei9go

They think in the US that this is what they call a "compliance car" and will not be built in any volume and will probably be only available in about 12 states who have California type laws.

ei9go

ei9go wrote: »

They think in the US that this is what they call a "compliance car" and will not be built in any volume and will probably be only available in about 12 states who have California type laws.

That was the initial plan, they are going to mass produce it, it comes to Europe next year.

They are also going to make a 200 mile range spark and offer the two and see what people actually buy.

Sesshoumaru

The official website say 0 to 60 mph in less than 8 seconds.

http://www.chevrolet.com/spark-ev-electric-vehicle.html#technology_section

Spark EV features an innovative electric propulsion system drive unit paired with the lithium-ion battery. This mini car has big bite and boasts instant torque. The connection is direct: head, right foot, power, pavement. Without the traditional transmission, torque has nowhere to go except to the tires and road. This helps explain why Spark EV feels so powerful and exhilarating while also achieving 0 to 60 mph in under eight seconds. Tuned specifically for its electric propulsion system, Spark EV puts power in all the right places at the moment it’s needed for a sporty and responsive ride. And Spark EV features a turning radius of 32.6 feet, which beats out the Mini Cooper, so parallel parking in the city is seamless and simple.

I don't know what else you could compare it to, but in comparison to a Mini Cooper, it is faster to 60mph. 10.4s is quite slow for the Mini Cooper Automatic.

http://www.mini.co.uk/model-range/hatch/mini-cooper/information/



It's no Mercedes SLS AMG E Drive, but it looks like it could be fun little car to drive

Big Nasty

colm_mcm wrote: »

the chinese rip off is called the Chery QQ


You can even put the doors from the chery on the Chevy and they'll fit.

That's just the way the Chinese pronounce Chevy silly! :eek:

Matt Simis

Matt Simis wrote: »

It doesnt matter, if the "power" discussed is horsepower for rotating objects and its not even moving, then it has no effective torque or power, it cannot be measured.


400ft-lbs * 0rpm / 5252 = 0 power.

And, as Cino already said, 400ft-lbs peak torque with 130hp =
RPM formula = HP x 5,252 / torque
Spark EV = 130 x 5252 / 400 = 1706rpm at peak power.



Mad_Lad, I dont think its correct to state that there is some "difference" in Electric vs Combustion motors regarding stated power and torque. These are measurements, source of power doesnt matter. A 130hp EV would have the same peak power as a 130hp Passat TDI and with similar gearing and weight, pretty much the same performance. The aforementioned A6 3.0TDI produces 370ft-lbs of torque from 2200 to 3400 RPM (and I think there are faster versions of the engine), which is far more "power" than 400ft-lbs at 1700rpm (peak).

Its also not correct to state that Electric motors "go to 15000rpm" and have the same torque from near 0rpm, they dont on either account, they loose torque as RPM increases and they mostly do not rev anywhere near 15,000RPM in EV applications. There is also a significant difference between DC and AC motors, which in its own world is like comparing the merits of Petrol vs Diesel.


DC Motor for EVs:


AC Motor for EVs:

I think were getting confused ? I think we're all thinking about different things ?

For an ac permanent magnet motor such as the Leaf, torque is a function of current and rpm voltage.

SO turn up the amps and you can get 400 lbs of torque without needing to increase rpm, you also increase the total HP out and watts consumed.

Matt Simis

Deleted User wrote: »

I think were getting confused ? I think we're all thinking about different things ?

For an ac permanent magnet motor such as the Leaf, torque is a function of current and rpm voltage.

SO turn up the amps and you can get 400 lbs of torque without needing to increase rpm, you also increase the total HP out and watts consumed.

Well certainly there is some confusion somewhere!
What we are stating is it doesnt matter how the power was developed (ICE, EV, Wind), power and torque are measurements, to compare disparate things.. that was infact the whole reason Horsepower was invented, to compare "powered" mills to horse drawn mills.

It doesnt/shouldnt matter that a DC motor varies torque from Volts or an AC from Frequency+Volts or an ICE from increased fuel injection/rpm or human from muscle flex etc.


I'm actually a fan of DIY EVs, this is one of the sites I read:
http://www.electric-cars-are-for-girls.com/electric-car-motor.html

Torque and Electric Car Motor Poles
Question: So what's torque got to do with it? Is that a constant, related to the type/size of motor, and moved to the right or left on the graph by the number of poles? I've never understood the poles bit very well. More poles means more low-end torque, less high-end torque? Is there a limit to the number of poles a motor can have?

Answer: Most AC electric car motors are 4 or 6 pole. The more poles, the slower the motor will turn. If both motors have the same horsepower, the 6 pole motor will have more torque and less speed. HP = speed * torque.


Motor torque is related to "slip". Slip is the difference between actual electric car motor speed and commanded motor speed. For example a DC car at a stop can generate lots of torque because 100 volts will produce 2000 rpm of slip. Once you achieve 1900rpm, the torque is limited because now you can only produce 100rpm of slip. With an AC electric car motor, the slip is not limited by voltage, it is limited by frequency, which is basically unlimited. So the motor can produce torque even at high rpms. The constant power nature of the AC electric car motor makes it feasible to drive 0-75mph in only one gear.
Picture a car with a big coil spring on the rear bumper. If you want to accelerate the car slowly, you would push on the spring with slight force, and this would compress the spring slightly "small amount of slip". If you want to accelerate quickly, you would command a large "slip", basically compressing the spring a lot.

DC Motors spin a certain rpm per volt. If 1 volt = 20 rpm, 2 volts will =40 rpm, and 200v will = 8000rpm.

AC motors will spin a certain rpm per cycle. If 1 cycle/second = 20rpm, 60 cycles/second will = 1200rpm. The motor controller can command any frequency it wants to the motor, and of course you need enough voltage and current to produce torque.
...for a DC motor, voltage will limit the max speed of the motor. Unless the motor has a separately wired field, this is true.

The concept of "slip" in the electric motor world is largely analogous to higher torque/acceleration at crank vs wheels in a regular car. I think..

Matt Simis

Matt Simis wrote: »

Well certainly there is some confusion somewhere!
What we are stating is it doesnt matter how the power was developed (ICE, EV, Wind), power and torque are measurements, to compare disparate things.. that was infact the whole reason Horsepower was invented, to compare "powered" mills to horse drawn mills.

It doesnt/shouldnt matter that a DC motor varies torque from Volts or an AC from Frequency+Volts or an ICE from increased fuel injection/rpm or human from muscle flex etc.


I'm actually a fan of DIY EVs, this is one of the sites I read:
http://www.electric-cars-are-for-girls.com/electric-car-motor.html



The concept of "slip" in the electric motor world is largely analogous to higher torque/acceleration at crank vs wheels in a regular car. I think..

Good Website, thanks.

Yes polls will effect torque also motor winding and current.