Fedex to develop and test hydraulic series hybrid delivery van
Fedex Ground is teaming up with hydraulic component manufacturer Parker Hannifin to develop and field test a hydraulic hybrid delivery van. The van will use a series hybrid layout similar to one developed by FEV that is being tested by UPS. The internal combustion engine will drive a hydraulic pump which will generate pressurized fluid to drive a hydraulic motor-pump. The second motor-pump will drive the rear axle. Under braking, the rear axle will drive the motor-pump to charge a high pressure hydraulic accumulator, capturing kinetic energy. During acceleration, the high pressure accumulator can provide driving force to the motor-pump to move the truck. The hydraulic hybrid setup has the advantage of being able to absorb energy more quickly than a battery, recapturing up to seventy percent of the kinetic energy compared to thirty percent for a typical battery. Unfortunately the capacity is limited. However it works well for this type of application that has a lot of stopping and starting and low speeds. The prototype is expected to be ready for testing by Fedex sometime in 2008.
[Source: Parker-Hannifin, via Green Car Congress]
Reader Comments (Page 1 of 1)
why not the LS2/LS7? 12:08PM (12/10/2007)
Hydraulic drive never seems to pan out on fast-moving vehicles, probably because the fluid is viscous.
It's great for load handlers, but I'll be surprised if this works on the street.
I'm not against hydraulic accumulators as energy stores, but putting the engine output through hydraulic drive even in stead-state driving seems like it's going to limit top speed and waste a lot of energy, lowering efficiency.
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