Spokane Transit Hybrid Coaches

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Spokane Transit Hybrid Coaches










The GM drive system is similar to other hybrid vehicles in that it uses a blending of diesel
and electric powerbut is different than most passenger vehicle systems because the diesel
engine must idle at all times to operate the power steering and other accessory systems such
as the air-conditioning.
When driving less than 10 miles per hour, the hybrid buses use the low-torque power from
the electrical drive system to move the vehicle. To sustain higher speeds, the hybrids must
use the power generated from the diesel engine. This blending is controlled by an on-
board computer that uses an extensive series of sensors to accelerate the diesel engine and
manage the power transition.
The electrical drive unit (the e-drive) takes the place of the transmission in the drivetrain.
The power to engage and accelerate the vehicle from a stop is delivered to the e-drive by a
large insulated cable that can deliver as much as 900 volts from the battery pack located on
the top of the vehicle.
The drive system uses an automatic traction control system like most new traditional diesel-
powered buses, but the braking system also serves as a generator to recharge the batteries.
This regenerative braking makes the vehicle slow down quicker than a regular diesel-pow-
ered bus when not under acceleration.
The integrated hybrid system is completely automatic and requires minimal training for
drivers to operate. The main point of emphasis with drivers is to be aware of the lack of
coasting speed when not under power.
Fuel savings over a twelve-year life cycle is expected to be between 31 and 35 thousand gal-
lons when compared to the fuel consumption of a standard diesel-powered coach.
Over the same life-cycle period, a hybrid coach will produce 352 tons less carbon dioxide
than a traditional diesel-powered coach.
Spokane Transit recently purchased three
40-foot Gillig diesel-electric hybrid buses
as part of a larger purchas