BAE Systems, a leading developer and producer of hybrid electric technologies, has launched its parallel hybrid green propulsion system for Class 6, 7 and 8 vocational trucks. It is the latest version of the company’s HybriDrive green propulsion system.
The propulsion system - currently in service on more than 3,000 transit buses in cities around the world - meets the demands of urban transit duty cycles which require low average speeds and frequent stop-and-go operation, said Mike Mekhiche, BAE Systems’ director of programs, power and energy management.
The HybriDrive parallel system is designed to address the needs of vehicles with duty cycles that require higher operating speeds and less frequent stops,” he said.
“Vocational truck fleets that transition to our heavy duty HybriDrive system will experience fuel savings not before seen in these truck classes,” said Steve Trichka, vice president of power and energy management for BAE Systems. “Our HybriDrive parallel system is the optimal hybrid electric solution for vehicles that operate in diverse duty cycles beyond standard urban operational modes.”
With more than 200 million miles of revenue service, more than 10 million gallons of diesel fuel saved, and more than 100,000 tons of carbon dioxide emissions prevented, the HybriDrive series system has proven itself to be one of the most efficient hybrid systems for the transit bus sector and has provided significant environmental benefits, according to Mekhiche.
HybriDrive series and parallel technologies both use simplified and proven components and controls to deliver their capabilities, he explained. While the series system does not use a transmission, the HybriDrive parallel system is based on a single electric machine integrated between the engine and the transmission.
The system can be installed with minimal impact to the vehicle, and enhances propulsion through an optimized blending of internal combustion engine power and electric power. The system’s energy management and control capabilities ensure all energy flow - such as propulsion and recuperation - occurs in a highly efficient fashion, resulting in lower fuel consumption and reduced emissions.
Main components
There are four main components to the HybriDrive system:
1. Energy storage system - Provides power during acceleration using proven lithium-ion batteries. The system is flexible and can be integrated between the truck’s frame rails and saddle bag or at the back of the cab.
2. Integrated electronic unit - Consisting of a power inverter and system/motor controller, it is the controller for the HybriDrive system. Based on vehicle speed, it controls when power is drawn from the engine and electronic power sources and efficiently blends them to provide optimum fuel usage.
It also controls when energy should be stored during deceleration.
3. Integrated drive unit - Consisting of a motor/generator and a hybrid transmission, it receives signals from the integrated electronic unit and connects with the appropriate power source for efficiency.
When the vehicle is accelerating, it is drawing power from the electrical power source (stored power). Once the vehicle is at an ideal speed, the power is drawn from the engine. During vehicle deceleration, energy is converted and stored in the electronic storage system.
For additional fuel and emissions savings, the HybriDrive system has an efficient “stop/start” function. When the vehicle is in idle position, the integrated electronic unit signals the engine to power off to eliminate drive line losses.
4. Engine - The HybriDrive system can be configured to operate with any heavy or medium duty engine.
The HybriDrive parallel systems’ power and torque ratings range from 95 to 145 hp and 300 to 400 lb-ft torque. The system is designed to support large bore heavy duty power plants ranging from 350 to 600 hp, with associated torque ratings of 750 to 2,150 lb ft.
BAE Systems’ HybriDrive series systems power vehicles by the world’s leading bus manufacturers, including Daimler and New Flyer in the United States, and Alexander Dennis and Irisbus Iveco in Europe.
The HybriDrive parallel system, in final stages of development, will see it first road trials this spring and is expected to be deployed in markets around the world in 2012.
For further information, visit www.baesystems.com.
