Heavy Diesel Hybrid Vehicles

Most locomotives are forms of a diesel electric hybrid vehicle.  The rail transport industry prefers this type of technology because of its reliability, durability and efficiency.  It provides more power at low speeds and improves the fuel efficiency of the diesel when used with electric engines.  Add regenerative braking and you increase the efficiency especially in stop and go conditions found in delivery trucks and transit buses.

The public transportation industry is pressured to lower fuel consumption and reduce emissions can take advantage of the diesel hybrid electric technology.  Diesel electric hybrid buses are now being used in New York, Seattle and Los Angeles.

New York City Transit has the largest fleet of diesel electric hybrid buses in the U.S. These buses use a serial hybrid platform where the diesel engine does not provide power to the transmission.  The smaller diesel engine in a serial hybrid vehicle turns a generator which charges on board batteries.  These batteries then provide power to the electric traction motor.  The batteries are also are charged by regenerative brakes which helps to slow and stop the bus.  This reduces the wear on the friction brakes. The diesel engine used in a serial hybrid is used only to power the generator.  This allow the engine to be much smaller than one used in a conventional diesel bus or even a parallel hybrid vehicle.  This smaller diesel engine can be run at constant optimum operating speeds further increasing the fuel efficiency of the vehicle while reducing the emissions.  This should also increase the life of the engine. 

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