Vehicle Operation; Instrument Cluster - Blue Bird TC/2000 Owner's Manual

VEHICLE OPERATION

Efficiency of Energy
To maintain smooth operation of the vehicle and efficiency of energy, the bus should be operated with a
constant easy pressure on the accelerator. The battery energy per mile required to move the bus increases
with speed. The range decreases with speed. A ten (10) MPH difference in speed will bring about a ten (10)
mile difference in vehicle range. Properly inflated tires have less rolling resistance than under inflated tires.
Warm tires have less rolling resistance than cold tires.
The motor will not produce torque or power if the brake pedal is pressed at all. A slight touch of the brake
will disable the motor controller, prevent it from applying any further acceleration power, and initiate elec-
tronic braking called regenerative braking.
Rolling
WARNING: There is no parking pawl to hold the electric vehicle. When brake pedal or parking brake is
not applied, the bus will roll forward or backward, depending on the slope of the road surface, whether or
not the vehicle is in neutral. While the bus is stopped, always have a foot on the brake pedal or engage the
parking brake.
When starting from a stop, the bus will roll freely after release of the brake until the motor torque acceler-
ates the bus, unless accelerating torque is applied prior to release of the parking brake. Be careful of
people/objects in front of or behind the bus when moving from a stopped condition.
Regenerative Braking System
The electric vehicle is equipped with a regenerative braking system that provides additional braking
assistance to the standard school bus hydraulic braking system. The regenerative braking system operates as
follows. Upon application of the hydraulic brake pedal, the motor becomes a generator and provides addi-
tional braking to the bus. The mechanical energy of the moving bus is converted into electrical energy that is
returned to the Traction Battery Packs. The energy that is returned to the Traction Battery by the regenerative
braking will increase the range of the bus. This increase can be as much as 20 % as compared to a system
without regenerative braking.
The first movement of the brake pedal applies the regenerative braking by responding to a small rise in
hydraulic brake fluid pressure. The regenerative brakes will provide aggressive braking for the vehicle dur-
ing the first part of the brake pedal movement with very little pedal effort. If more aggressive braking or a
panic stop is required, the hydraulic power disc brakes are still present and can be fully activated by pressing
the pedal with normal foot pressure. Under most conditions, the regenerative brake will provide almost all of
the necessary braking. This braking combination will extend the natural life of the friction brakes. It will not
"hurt" the bus or the regenerative brakes to "ride" the regenerative brakes down a long hill which under
normal circumstances will overheat or destroy hydraulic friction brakes if used in this manner.

INSTRUMENT CLUSTER

Most of the features on the instrument cluster are typical for all school busses. This section will cover the
changes to the instrument cluster that are specific to the operation of the all electric school bus.
1. Amp Hour Gauge - This gauge represents the available energy of the electric vehicle. This indicates
range much in the same way a combustion engine fuel gauge provides the status of gasoline available.
As in a combustion engine operation the range is determined by the efficiency of driving and the
speed of the vehicle. Use this gauge as an indicator of the % of a full battery charge available. The
amp hour reading multiplied by the battery pack voltage is the remaining energy in the battery pack
in units of watt hours.
Volt Meter - Shows the voltage of the 12 volt battery system that operates the vehicle 12 volt electron-
ics. This gauge will read the same as if the vehicle was a standard internal combustion powered
vehicle.
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