Matt, Mouse,

What do you guys think of these?

Matt Farnsworth Wrote:
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> I drive for Pullman Transit (Pullman WA). Our new
> bus purchases since 2013 have been Gillig
> Hybrids.
>
> Some of the frills have changed, and I can tell
> the radiator tank arrangement has changed from
> 2014 - 2017 but the basic layout of them has
> remained the same. Very similar to a diesel
> locomotive, with the addition of batteries. There
> is a Cummins ISB diesel engine. It is not
> connected to the wheels in any way. It only
> powers a generator. This generator provides
> electricity to the batteries which are located in
> the large hump on the rear of the roof. These
> batteries then power a traction motor that is
> connected to the rear differential. No
> transmission other than reduction gearing in the
> motor itself. I know these have a maximum speed
> of 60-65 MPH, above that the traction motor spins
> too fast and is at risk of damage.
>
> One thing that is very interesting about these is
> the diesel engine speed is totally independent of
> the vehicle speed. When first started up the
> engine idles for a minute, then reves up very high
> to get the batteries fully charged then drops back
> to idle. When driving the engine stays at idle
> for a few minutes then slowly reves up.
>
> Braking is primarily accomplished through
> regenerative braking. The traction motor is
> turned into a generator, the diesel engine drops
> to idle and the traction motor is used to charge
> the batteries. This regen braking is VERY
> powerful, only a very light touch is needed on the
> brake pedal. It works down to about 2-3 MPH, at
> which point it cuts out and braking is then
> accomplished only by the air drum brakes. The air
> brakes continue to work at any vehicle speed, but
> rarely are needed. There is a switch on the dash
> to turn off the regen braking, sometimes this is
> needed in slick snowy conditions as the regen
> braking can cause the wheels to lock up and slide
> in the snow and ice.
>
> Pullman has a lot of steep hills similar to
> Seattle and San Francisco. Because of the
> electric traction and regen braking these hybrids
> do wonderfully on our hilly routes.
>
> Matt Farnsworth
> Pullman Washington