Heavy Truck Hybrids: Technology Basics

Hybrid electric vehicles (HEVs) combine electricity and internal combustion engine power. The net result is a more efficient vehicle and a cleaner one. Essentially, a heavy-duty HEV has the following components/systems: an internal combustion engine an electric motor/generator, a rechargeable energy storage system (batteries and/or ultracapacitors), a power electronics system, and regenerative braking.

Internal Combustion Engine

A typical V 8 diesel engine is present on a heavy-duty HEV. As with any truck engine, it burns diesel and turns it into mechanical energy that powers the vehicle. Research is conducted to design and develop more efficient diesel engines that produce less emissions (less contaminants).

Electric Motor/Generator

In addition to the traditional diesel engine, heavy-duty HEVs have an electrical motor that is used to create or increase the torque that drives the truck's wheels. However, this electric motor/generator has a dual purpose: it can either use electricity to create torque, or by reversing the process it can use the use torque to generate electricity.

Rechargeable Energy Storage System

Th energy created by the electrical motor/generator has to be stored within the car for further use. Usually batteries are set up in the truck to store electricity. These are advanced systems for storing energy not simple batteries. Sometimes ultracapacitors are used, in addition to or in conjunction with batteries. These system have electrical, thermal, and safety control features.

Power Electronics System

The Power electronic system is a vey important component of a heavy-duty HEV. It converts, manage, and distribute electrical power and in the various hybrid vehicle applications. This system include converters, inverters, sticks, cooling Systems. In heavy HEVs, converters and inverters control the electrical signal between the energy storage unit and the motor/generator to provide power at critical times.

Regenerative Braking

Through regenerative braking it is possible to generate extra energy that would otherwise be lost (in form of heat and sound) when the vehicle decelerates. This is the purpose of regenerative braking. Basically as the driver decelerates a heavy HEV, the Enghien and electrical motor becomes an electricity generator and uses the kinetic energy of the vehicle to generate more energy (electricity) that is stored for later use.

Sources:

Advanced Heavy Propulsion Systems

K. D. Povey. 2006. Hybrid cars. KidHaven Press,ISBN 0737734841, 9780737734843