Azure Dynamics series hybrid bus completes US government tests
Public transit agencies in the US will now be able to buy series hybrid shuttle buses from Azure Dynamics and get federal subsidies. One of the CitiBus Hybrid HD Senator buses successfully completed a durability test program at a facility in Altoona, Pennsylvania. The test simulates seven years of use in an urban transit environment. Like the Chevy Volt, the Azure bus is driven only by the electric motor. The motor gets electricity either from a battery pack or the engine-generator set which uses a GM 4.8L V-8.
[Source: Azure Dynamics]
Reader Comments (Page 1 of 1)
why not the LS2/LS7? 5:42PM (12/02/2007)
Okay. Where's the batteries? I don't see them in that pic. If you have a 200HP engine to recharge your batteries, then you most definitely have a big-ass battery pack.
So where is it and how much does it cost?
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Sam Abuelsamid 5:54PM (12/02/2007)
See Energy Storage System (aka battery pack, cost unknown
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Joseph 6:29PM (12/02/2007)
Although the engine is continiously recharging the batteries, it still looks too small to supply the required power; it's shown as about the same size as the inverter!!!
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Dad 6:00PM (12/02/2007)
Great use of hybrid technology. Buses are the perfect platform, given their location (cowded city streets) and duty cycle (stop and go). Bravo!
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Chris M 8:31PM (12/02/2007)
Most of the power the IC engine generator produces goes directly to the motor. It doesn't need to be very big, as its power is supplemented when needed by the batteries.
The batteries are charged by regenerative braking, and when the IC engine generator is producing more power than is needed to propel the bus.
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rick smith 10:41PM (12/02/2007)
it might be an ultracap-battery combo made by maxwell/lishen thats been in publicized lately..
http://www.electronicstalk.com/news/maw/maw140.html
http://www.edn.com/index.asp?layout=blog&blog_id=1470000147&blog_post_id=450017845
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rick smith 10:43PM (12/02/2007)
confirmation???...
http://www.greencarcongress.com/2007/06/azure-dynamics-.html
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why not the LS2/LS7? 2:06AM (12/03/2007)
The "Energy Storage System" in that pic is not large enough to store a useful amount of energy. It wouldn't store enough energy to allow the engine to turn off except at stoplights.
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Chris M 3:46AM (12/03/2007)
LS2/LS7: You're judging the size of the "energy storage system" by a drawing, which might not be to scale?
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GoodCheer 5:55PM (12/03/2007)
I think the image in the article is to scale. But if the vehicle isn't a plug-in, then there's no point in storing more energy than it would take to accelerate the vehicle up to highway speed, plus a safety factor (unless you have long AND steep hills to go up or down):
Let's see, KE = 1/2 mv^2 :
I'll estimate 22,000 # and 67 mph because those numbers are nice and round in metric.
1/2* 10,000kg * (30 m/s)^2 = 4.5MJ = 1.25 kWh.
Lead acid batteries have an energy density of ~65 Wh/l, so the battery would need to be 20l of lead. That's about 0.7 ft^3.
I haven't added a safety factor here yet, or factors to reduce the duty cycle of the battery, so let's say we'll quadruple that number to be comfortable; 2.8 ft^3.
Let's now assume that packaging the battery doubles the pack volume-> 5.6 ft^3.
Just eyeballing from the image in the post, I would say the pack is ~1' x 1.5' x 4' = 6.0 ft^3.
I'm just pulling numbers out of my hat, but I don't see any problem with the ESS size. LS2/LS7: What are you basing your statement "not large enough to store a useful amount of energy." on? What do you consider a useful amount of energy? Remember energy goes as the square of speed, so the pack I described could accelerate the bus to 33 mph 4 times with the restricted duty cycle.
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Domenick 4:23AM (12/04/2007)
All math aside, it (energy storage system) looks plenty big to me. ^_^
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