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2010 Fisker Karma Hybrid - Preview

2010 Fisker Karma Hybrid - Preview

"Still, the Karma's Q-Drive powertrain, developed with a company called Quantum Technologies, does have a gasoline engine: an efficient, turbocharged 2.0-liter four-cylinder, provided by General Motors, generating 260 horsepower. The gas engine is mated to a compact generator under the hood, and generates electricity to charge the battery pack. Fisker says the Karma's fuel tank will be large enough to give it a minimum 300-mile range between fuel stops, in the absence of any plug-in charging."

 

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Nice ride, but with that $98,000 price tag, it is destined to become another feel good eco toy for the affluent. But the technology is impressive.

Hopefully the Chevy Volt (using the same basic power train design) will actually get out to market some day. And although not near as sporty, will at least be a little more attainable.

The only question I haven't seen answered by anyone is: what will happen to the national power grid if we all end up driving these type of cars? The overnight load increase will have to be significant.
 

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Can anyone explain to me why this car needs a 260 hp motor?

I assume the Fisker is like the Chevy Volt, meaning it is driven by electric motors only. The gas motor is only used to run the generator that provides juice to the motors, not the battery.

The Volt has a 53 KW generator which needs only around 79 horsepower to run (assumes 92% mechanical efficiency). GM claims this is enough power to run the volt at 70 miles per hour with the A/C running. 260 hp translates to 193 KW, I'm guessing they won't want to run the motor at the redline, so assuming a more reasonable power draw of, say 200 HP would imply a generator capacity of around 149 KW, almost 3 times the size of the Volt.

But why would you need this amount of power? Remember GM says you only need 70 or 80 HP to run an electric car at highway speeds. Is Fisker planning to run this car at triple digit speeds on the generator only? Or are they planning to both drive the car and recharge the battery at the same time? This is much more inefficient as you are suffering power losses going from the gas motor to the generator, then losses again going from the generator to the battery, and finally a third set of losses going from the battery to the electric drive motors powering only the electric drive motors eliminates the power losses going to and from the battery.

I also find it interesting that Fisker wants to use a relatively expensive engine, considering it does not actually drive the car. It seems to me, a much simpler and less costly engine could have been used.

Needless to say there is a lot about this car that I don't understand. I guess the rational for their design decisions will become apparent as time goes by.
 

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Can anyone explain to me why this car needs a 260 hp motor?


But why would you need this amount of power? Remember GM says you only need 70 or 80 HP to run an electric car at highway speeds. Is Fisker planning to run this car at triple digit speeds on the generator only?
I was wondering about this as well. I think it is a matter of required "reserve" power generation. Since the car is a true electric drive, like the Volt; then you need the extra HP to spin up that generator enough in high draw situations (battery reserves depleted from previous evenings charge because you have already driven 50 miles, but still wanting to pass someone at 120 mph. :lol::lol:) There is why they are packing enough power generation capabilities, to satisfy the "sports car" requirements all the time.

Ideally, the LNF would probably be running only about 2000 RPM for "normal" power generation. So well below turbo boost kicking in and running at peak efficiency. (don't know the HP numbers there, but guessing in the neighborhood of only 150 or so) But, it has the potential of going full turbo boost and 5500 RPM when required to spin up that generator for max generation. (now at 260 HP/Torque)

No matter what, I agree that it does seem to be a little bit of over kill. But I think they are covering their bases for the sports car enthusiast crowd. I know that GM has the little 1.5L version of the LNF deployed in Europe. I can't remember the exact numbers, but peak HP under boost was somewhere around 200 HP. So I would think that non boost, 2000 RPM running would come in closer to the 120 HP mark. That might be a really good alternative power plant that would be a little more efficient, but still offer enough "potential" HP/Torque under full boost to satisfy the "sports car" power generation requirements.:thumbs:
 

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GS Stage 1, I think what you say makes sense. Looks like Fisker is biasing their car more towards performance than efficiency, although I bet they will still advertise it as a "green car" so that wealthy actors and such won't be ashamed to be seen in it.
 

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Yes the car at it's current price is kind of a waste. Much better cars can be had at the price and people that can afford the car really are not interested in fuel prices anyway. With the lack luster performance from the car the only person I can see buying this is a Rich Ecofag and thinks it looks pretty. He won't ever drive it and the battery will probably go bad from the lack of use.

Just chalk it up to more Eco-crap to clog the arteries of history and our landfills.

:cheers:
 

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I was wondering about this as well. I think it is a matter of required "reserve" power generation. Since the car is a true electric drive, like the Volt; then you need the extra HP to spin up that generator enough in high draw situations (battery reserves depleted from previous evenings charge because you have already driven 50 miles, but still wanting to pass someone at 120 mph. :lol::lol:) There is why they are packing enough power generation capabilities, to satisfy the "sports car" requirements all the time.

Ideally, the LNF would probably be running only about 2000 RPM for "normal" power generation. So well below turbo boost kicking in and running at peak efficiency. (don't know the HP numbers there, but guessing in the neighborhood of only 150 or so) But, it has the potential of going full turbo boost and 5500 RPM when required to spin up that generator for max generation. (now at 260 HP/Torque)

No matter what, I agree that it does seem to be a little bit of over kill. But I think they are covering their bases for the sports car enthusiast crowd. I know that GM has the little 1.5L version of the LNF deployed in Europe. I can't remember the exact numbers, but peak HP under boost was somewhere around 200 HP. So I would think that non boost, 2000 RPM running would come in closer to the 120 HP mark. That might be a really good alternative power plant that would be a little more efficient, but still offer enough "potential" HP/Torque under full boost to satisfy the "sports car" power generation requirements.:thumbs:
Here is a quote from the website Karma by Fisker Automotive

Karma uses Q-DRIVE plug-in hybrid technology, developed exclusively for Fisker Automotive by Quantum Technologies. A fully-charged Karma burns no fuel for the first 50 miles. Venture further and the gasoline engine turns a generator to charge the lithium ion battery. Once the 50-mile electric range has been exceeded, the car operates as a normal hybrid vehicle. This balance of electric and gas range makes it entirely possible that Karma drivers who charge their car overnight and commute less than 50 miles a day will achieve an average fuel economy of 100 mpg (2.4L/100km) per year.
 

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Nice ride, but with that $98,000 price tag, it is destined to become another feel good eco toy for the affluent. But the technology is impressive.

Hopefully the Chevy Volt (using the same basic power train design) will actually get out to market some day. And although not near as sporty, will at least be a little more attainable.

The only question I haven't seen answered by anyone is: what will happen to the national power grid if we all end up driving these type of cars? The overnight load increase will have to be significant.
According to the website Karma by Fisker Automotive the Fisker Karma lists for $87,900 and may be eligible for a $7500 tax credit. The convertible does not have pricing yet.

http://karma.fiskerautomotive.com/files/karma_pre_order_form_2008.pdf
 

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Can anyone explain to me why this car needs a 260 hp motor?
Performance!

I forgot the details, but if memory serves me, the engine not only charges the battery but can directly drive the electric motor. The driver can be environmentally friendly by driving nicely and going electric, only using the engine to charge the batteries when range is extended....OR, the driver can say "to hell with green" and take advantage of the batteries AND the engine simultaneously to drive the electric motor. This gives the Karma exceptional sports car like performance.

Also, while the engine is 260HP, I believe its optimal run point is at an RPM well below the 260HP point. So, while it is capable of delivering 260HP, I doubt it ever reaches that point. The car gets it sports car performance from the COMBINED battery and engine.

Edit: Here you go, from an earlier thread, http://www.skyroadster.com/forums/f24/rl-gxp-engine-moves-upscale-28858/index2.html#post404725:. The LNF only runs at about 134HP.

(data extracted from C&D, March 2009):

Battery Pack (full charge): 200KW -> 268HP
LNF: 100KW -> 134 HP

Sports mode: 268 + 134 = 402HP

But it's a heavy car (4600lbs!!!), so the 400HP gets it to 60 in just under six seconds.

And if you're wondering why the LNF is only producing 134HP vice the rated 260HP....it's because it runs at around 3000 RPM for fuel efficiency and, reportedly, charge efficiency.
 
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