What is a matter with these people trying to put hybrid buses on freeway commuter lines? Are they idiots? We have the same idiots here in Washington state as they put hybrids to work in the same situation (sound transit express).

Then, they have to go to an engineering group and pay several hundred thousand dollars for a study which will say "use hybrids for normal stop-and-go bus routes not on commuter routes". When will they start to use their heads?

gasoline engines-give me a break! My understanding is that in RVs nobody uses gas engines on higher end vehicles due to their proclivity to overheat and wear out quickly- so why would one use them for transit buses?

Here's a MUCH cheaper solution: Instead of buying a fleet of $200,000 CNG-powered buses, why not mount solar panels on the relatively huge surface area of the hybrid bus's roof? A panel I saw at Epcot in Disney world that was made in 1992 or so was about 1/4 to 1/5 the area of a bus's roof and could provide up to 400 watts of electricity. I am sure a 1600 watt (or more, given today's new thin-film tech and other improvements) would be able to adequately recharge the battery systems to power A/C units- especially on the hot, sunny days when the units were failing.

But then again, what's better than wasting city budget on unnecessary measures?

Joey, 1600w is the equivilent of 2 horsepower. 2hp isn't going to make a bit of difference for a bus trying to do 60mph, which given the weight and aero drag, probably needs well over 100hp, possibly close to 200hp to get up to and hold that speed. I'm sure the 6.8 liter V10 provides a ton of power on it's own, and if even that isn't enough to get the job done, solar panels aren't going to help.

As much as anything else, the transit agency might have been seduced by the notion of being the first to go "100% hybrid." What escapes my comprehension, however, is their failure to anticipate problems on the highway routes. The fact that hybrid technology's strong card is stop-and-go traffic has been well known for years. The fact that a Ford V-10 gasoline engine is insufficient for powering a full size bus at highway speeds with air conditioning running against triple-digit heat should surprise no one. On the face of things, I blame the transit operator and bus purveyor in equal measures for not realizing that these problems might arise.

For a great example of the city/transportation planners placing the blame on the equipment when it was not used for its intended purpose go to sound transit's website (Washington State puget sound area) and look for their reviews of the Community Transit EXPRESS hybrid buses. They say it failed to meet the fuel economy expectations by a large degree...and they used these buses for EXPRESS routes where you would have 4-5 stops: 1 at a main park & ride transit center, 3-4 at highway stops within 3 miles of the transit center and then the bus would drive 20-30 miles by highway to reach Seattle. The buses for the regular city routes with a stop every 1-2 blocks? Standard Diesel or CNG...talk about backwards.

on power for air conditioning, each human being is roughly equivalent to 250 W. of course, that amount of heat into the bus is probably dwarfed by the hundred degree plus temperature on the outside and the energy inefficiency of a bus frame.

As for serial hybrids versus parallel on highways, I have not seen a good analysis of the relative efficiencies of the drive trains. Personally, I find serial hybrids aesthetically pleasing because it opens up interesting options with regards in wheel motors, dynamic Drive control, better antilock, antiskid braking, etc..

In order for a serial hybrids be effective at speed, the average energy output of the generator must exceed the average energy requirements of the rest of the system. Otherwise, you'll never charge the batteries and the system will slow until its energy consumption matches that of the generator output.

I can't help but wonder about the windows in these buses. How much solar heat do they let in? Hopefully they reflect a large portion of it because 100 plus temps in the Sacto area are not uncommon, IIRC. Is any effort made to insulate the interiors, i.e., is there any insulation in the roof, the sides, etc? This would all seem to help with the amount of a/c needed. Do these a/c systems just run continuously or do they monitor the interior temp and run as needed?

I Must correct my previous post.

It was Maxwell that made the capacitors.

By seaching for the buses I found that they do have a limited electric range perhaps 5 to 15 miles.

The gasoline engine seem to have enough generator capacity for the motors.

The spacings are modified but the pairs can be seen

Here are some of the comparisons with Ultracaps.

ZEBRA Battery Pack Thunderpack II
Ultracapacitor Pack

Usable Energy 18kWh 0.3 kWh
Power 32kW Over 150 kW
Energy Density 87 Wh/kg 4 Wh/kg
Power Density 0.16kW/kg 1.5kW/kg
Expected Life 2.5-5 year 10-12 years
System Cost 375 $/kW 100 $/kW
Life Cycle Cost $1125/kW 100$/Kw

System cost $ 667 /kWh $50,000 /kWh
Time at 30 HP 40 minutes 40 seconds
Time at rated power 34 minutes 7.2 seconds

Thunderpack II costs $15,000. It has .3 kwh of energy
storage; equal to 1/60 of the Zebra or equal to 1/4
the capacity of a deepcycle RV battery (12 volts at
100 amp hours or 1.2 kwh). Thundervolt II can produce
32kw for 33 seconds.

The Zebra Battery costs 375*32=$12,000. It can produce
32 kw (42 horse power) for at least 30 minutes.

The new Zebra Battery probably has a useful life of
10-12 years as well even though it is not guaranteed
for that long, so the life cycle cost is probably not
the $1125 $/kw or three times its new system cost.
Unlike lead batteries, the unit can withstand, without
repair, the failure of several cells perhaps as many
as ten percent of them with only a ten percent drop in
voltage and capacity. There is no maintenance cost, and there are no high power semiconductors in the battery to fail.

Stingray transit bus with 12 Zebra batteries can go 130
miles on battery alone.

Refitted school bus can go 50 with 6 Zebra Batteries.

The Elk Grove busses would have to have five or six zebra batteries to run at full power without engine running, but there might be some reason to add more to make it into a plug in hybrid.