[gwyllion]

Originally Posted by knighty

2 x 75KW - very interesting.....yep same spec but the axle based motor generator is a very different design to the porsche system which was a huge mother, it now looks buch more compact

well it now sounds like the Audi system is only 10-20Kg lighter that Toyotas solution, which is not a huge amount, but noteworthy none the less........

Earlier this year we already discussed the weight and power output of the Porsche/Williams hybrid system: http://tentenths.com/forum/showthrea...78#post3011078

The weight of Porsche/Williams flywheel accumulator is 47 kg. The whole Porsche hybrid solution weighs 105 kg in total, mainly because of its heavy front axle motor/generator. So Audi was able to shed off around 20 kg with a more compact front axle and shorter electric wiring and cooling tubing.

The original Supra hybrid system, when it was put in the open Dome S101.5 in late 2008, reportedly weighed a massive 200 kg. Toyota has not released weight numbers of the THS-R solution in the TS030, but there are some hints in the RCE article.

'Our hybrid system is huge and heavy,' admits a surprisingly candid Murata. 'We have to keep to the minimum weight of 900 kg. Usually without the hybrid system, the car is around 750-800 kg. The heaviest sub-system on the car is the hybrid, but we can also carry ballast.'

'The TS030 chassis has clearly been designed to be able to accommodate the four-wheel drive system and the wheelbase and overall weight distribution have taken that into account. When we use the rear system we have to put ballast in the front. The ACO does not limit the weight of the hybrid system, but it is difficult to keep to the 900 kg, and the ballast is actually very small," explains Murata.

So knighty's estimate of 100 kg seems accurate. The front system is probably a bit heavier than the rear system.

The additional weight of the Toyota solution can be explained by the difference in capacity. The Nisshinbo supercapacitors in the Toyota TS030 can store 1 MJ, whereas the Williams flywheel in the Porsche 911 and therefore probably also in the Audi R18 e-tron quattro can only store around 700 kW.

http://www.popularmechanics.com/cars...ybrid-flywheel explains that Porsche choose the flywheel accumulator instead supercapacitors because it weighs less for the same energy capacity.