BMW Megacity Electric Car

[WhiteBlue]

http://www.autocar.co.uk/News/NewsArtic ... rs/249050/

BMW's Project i Megacity electric car will be launched in 2013.
It will be a full five-seater in the Golf class, it will be rear-engined and rear-wheel drive, establish a new design language for electric cars and will be constructed from lightweight carbonfibre. However, it is expected to feature signature BMW design features, such as the kidney grille and Hofmeister kink.
The Megacity will also be marketed under its own brand, and will eventually feature a range of cars, including sports versions.
BMW believes that it has developed a radical, lower-cost, mass-market-compatible means of producing carbonfibre monocoque bodywork that will dramatically reduce the Megacity's potential weight, improving not only its range but acceleration too.

That sounds like an interesting concept. McLaren's MP4-12C carbon monocoque numbers will be quickly eclipsed by the Megacity I reckon.

[Just_a_fan]

They'll do well to produce a 5-seater monocoque weighing less than 80Kg...

[Pandamasque]

Stefan Automotive will soon be on par with them, I reckon.

[JohnsonsEvilTwin]

What will a carbon monocoque look like after an acccident?
And will NCAP be as forthcoming with the results?

I realise the trend for lighter cars, but within the same design parameters heavier cars are safer as they can absorb more impact......Just a thought.

[autogyro]

What will a carbon monocoque look like after an acccident?
And will NCAP be as forthcoming with the results?

I realise the trend for lighter cars, but within the same design parameters heavier cars are safer as they can absorb more impact......Just a thought.

Simple, make the roads safer and ban all heavy vehicles.
Brilliant, no more of those pig ugly 4x4s with little girls driving them.
Oh by the way, put all the freight on railways, far more efficient and it would free up space on the roads.

[RH1300S]

This is the way to go in the future - reduce weight. Less energy is required to achieve the same performance. Smaller tyres required etc. etc.

Lighter cars will have accidents with less energy. Roads full of heavy cars have a lot of energy to dissipate when they do hit each other.

You might argue that it would be quite easy (ish...)to design a light car with good safety features - giving it good passive safety. Additionally the active safety of a light car is better (less mass to stop/turn in avoidance).

[marcush.]

This is the way to go in the future - reduce weight. Less energy is required to achieve the same performance. Smaller tyres required etc. etc.

Lighter cars will have accidents with less energy. Roads full of heavy cars have a lot of energy to dissipate when they do hit each other.

You might argue that it would be quite easy (ish...)to design a light car with good safety features - giving it good passive safety. Additionally the active safety of a light car is better (less mass to stop/turn in avoidance).

the future is in the past...for decades the buzzword was aerodynamics..not a mention of weight ...until a Golf had reached 1200kilo curb weight thats a cool 505 increase from where the Golf started...thats development at its best...
then we had the Airbag and safety hype ,very good thinking to carry 15 kilos of pyrotechnics in all cars to help save the life of those who actually get involved into an accident where the bag is actually needed.
On a sidenote ,just look beneath the cover of a current passenger car seat or the
hard plastic mouldings of the passenger compartment...i bet if you start the design of components under the aspect of avoiding them doing harm to the passengers you could possibly do away with a lot of these questionable inventions.

light cars... you do not even need a reverse gear for this.. :
http://www.stefan-arold.de/pics-fifties ... ittger.jpg

[raceman]

light cars... you do not even need a reverse gear for this.. :

+1 for perfect caption marcush.

[JohnsonsEvilTwin]

Autogyro fair point, and Im in agreement.

However do you really think we will see a carbon monocoque Range Rover in the next 15 years? The chelsea tractor crew would not stand for such clear thinking....

[Mysticf1]

So if you damage the monocoque in an accident, will it be repaired or thrown away?

[marcush.]

So if you damage the monocoque in an accident, will it be repaired or thrown away?

You will throw away a Elise ,so why not a Smart ...

Audi has come up with special trained and equipped repair centres for their ASF Aluminium bodywork ...so to perform repairs with carbon fibre in a controlled
certified manner with dedicated repair methods seems to me even more stright forward than repairing aluminium spaceframes.
For that matter ,have you even tried to weld one of those thin gauge high tensile strength steels currently used in steel structures ? I doubt and in any case its forbidden anyways... theres actually no drawback in composite repair if it is done correctly .time moves on.

[RH1300S]

the future is in the past...for decades the buzzword was aerodynamics..not a mention of weight ...until a Golf had reached 1200kilo curb weight thats a cool 505 increase from where the Golf started...thats development at its best...

Agreed! Don't get me started on that one! Cars are generally far too heavy these days.

A couple of comments about the carbon monocoque - I applaud BMW for aiming light not using carbon composites. While I'm at it -- let's put in a round of applause for Gordon Murrays T25 concept too.

I can't claim to know too much about composites, but it seems to me that at some point any type of chassis construction reaches the point where it can't be repaired. It happens everyday with steel cars. There's no reason why a composite chassis should be a poorer proposition - in fact there are opportunities to make it easier to repair. F1 tubs can survive sizeable crashes with only the crash structures needing replacement.

[Just_a_fan]

What will a carbon monocoque look like after an acccident?
And will NCAP be as forthcoming with the results?

I realise the trend for lighter cars, but within the same design parameters heavier cars are safer as they can absorb more impact......Just a thought.

They use subframes at the front and rear. These deform in the impact and thus deal with the energy. The central c/f bit is left intact.

At least that's what McLaren have done and their MP4-12C c/f tub was used for three crash tests. That's the same tub used three times!

And a heavier car is only better off in a head-on crash against a light car - it carries more energy for the same speed and the lighter car comes out badly because for a given speed (assuming both cars at that speed in a head-on crash) the lighter car will probably end up being pushed backwards which means its occupants will experience larger accelerations and thus are more likely to be injured.

The McLaren F1 is the only car that was able to be driven after its crash test and it was pretty light (<1100kg).

[WhiteBlue]

The Megacity aims at a main market segment with the Golf size. The German government aims at 1 million electric vehicles on German roads in 2020. BMW will go for at least 10% of that market if not 15%. This means that they will have to ship 150.000 vehicles in six years. The average production capacity for the German market would be 25.000 cars per annum. Upscaled to world demand and BMW market share you can multiply this by five. So an educated guess at BMW production capacities for this carbon composite bodied car would be 125.000 cars per annum. This is substantially above anything McLaren can ever expect to produce. If the plan works out this will probably be one of the biggest carbon fiber based projects of the decade and significant economy of scale benefits should be expected.

[Just_a_fan]

@WB

Indeed, the volume figures are large: makes me wonder how much of the dreaded CO2 will be produced making all of that c/f...

BMW will have to use the types of systems being pioneered by McLaren (and Lamborghini for the Gallardo replacement I believe (and also by BMW for the roof of the M3?)). Traditional c/f just isn't practical for mass production but the new systems are. The MP4-12C tub is a single piece rather than lots of 'bits' stuck together as the F1 was.

All of these electric cars are going to need some serious increases in grid generation too. The UK won't have any electric cars in 10 years time. Why? Because we won't have any electricity to charge them with!

I find it ironic that the only way we'll be able to power all of these green cars is by building several dozen nuke power stations. As a fan of nuke power I'm all for that happening but the greens will be most put out!