What is a diesel electric-hybrid bus? A hybrid vehicle is one that takes its power from more than one source. In the case of the Volvo B5LH diesel electric-hybrid buses, these two power sources are the traditional but much smaller diesel engine and an electric motor/generator powered by a 600 volt lithium-ion battery.
How do these hybrid buses work?
The Volvo B5LH chassis uses a parallel hybrid system to power the bus. This system enables the small diesel engine and electric motor to work independently or in combination with each other, depending on driving conditions, further reducing fuel consumption. The battery is charged using the electric motor that also acts as a generator, to capture energy that would usually be lost as heat into the atmosphere during braking. This energy is stored in the battery for later use.
What makes this hybrid bus different to other buses?
The diesel engine and electric motor are used to power the vehicle. What makes these buses different to traditional buses is that both units can work independently or together. When the bus accelerates away from a bus stop, the electric motor works independently and uses the stored energy in the battery to power the bus. During this time, the diesel engine is shut down as it is not required. Not only does this save fuel, it also removes emissions and noise pollution as the electric motor is virtually silent! It's only when the bus reaches speeds of about 10mph (17kph) that the small diesel engine starts and works in combination with the electric motor to power the vehicle, giving the battery an opportunity to recharge during braking.
