Hi guys, more hybrid news! :wink:
This is a picture of the latest experimental BMW X5, only just revealed to the press this week. I thought you might be interested because, for the first time in history, this BMW is a Hybrid. 8)
Of course BMW have never been all that interested in fuel economy and arent about to start now. Instead, BMW reckon customers will only be prepared to pay the hefty price premium required for hybrid vehicles is if they can demonstrate not a gain in economy, but a significant gain in performance.
To this end, theyve basically tripled the low rev urge of their X5 with electric assist. The standard torque of the 4.4 litre engine is about 470lbft. However, with electric assist, this jumps to a massive 1,350lbft (yes, you did read that correctly!) :shock:
Of course traditional batteries (unless unfeasibly enormous) just dont have the enormous discharge rate required for this kind of brutal output. Instead, BMW have achieved their power hike by fitting the X5 with a bank of ultracapacitors. Unlike batteries, ultracapacitors can be fully charged or discharged in seconds with massive power outputs, over millions of cycles with no appreciable degradation (vs ~1,000 for the best batteries, or ~10,000 for 60% discharges in the Prius battery).
Lying somewhere in between batteries and standard capacitors in format, todays ultracapacitors have energy densities about 1/10th that of the NiMH technology used in the Prius. This means that the BMW can discharge at full power for only 7 seconds before all charge is depleted. HOWEVER, because charge can be put back into the capacitor just as quickly, it means a lot more energy can be recouped from regenerative braking than into a battery without a buffering capacitor.
http://www.autoexpress.co.uk/?previews/previews_story.php?id=38421
This is a picture of the latest experimental BMW X5, only just revealed to the press this week. I thought you might be interested because, for the first time in history, this BMW is a Hybrid. 8)

Of course BMW have never been all that interested in fuel economy and arent about to start now. Instead, BMW reckon customers will only be prepared to pay the hefty price premium required for hybrid vehicles is if they can demonstrate not a gain in economy, but a significant gain in performance.
To this end, theyve basically tripled the low rev urge of their X5 with electric assist. The standard torque of the 4.4 litre engine is about 470lbft. However, with electric assist, this jumps to a massive 1,350lbft (yes, you did read that correctly!) :shock:
Of course traditional batteries (unless unfeasibly enormous) just dont have the enormous discharge rate required for this kind of brutal output. Instead, BMW have achieved their power hike by fitting the X5 with a bank of ultracapacitors. Unlike batteries, ultracapacitors can be fully charged or discharged in seconds with massive power outputs, over millions of cycles with no appreciable degradation (vs ~1,000 for the best batteries, or ~10,000 for 60% discharges in the Prius battery).
Lying somewhere in between batteries and standard capacitors in format, todays ultracapacitors have energy densities about 1/10th that of the NiMH technology used in the Prius. This means that the BMW can discharge at full power for only 7 seconds before all charge is depleted. HOWEVER, because charge can be put back into the capacitor just as quickly, it means a lot more energy can be recouped from regenerative braking than into a battery without a buffering capacitor.
http://www.autoexpress.co.uk/?previews/previews_story.php?id=38421