Diesel Electric Hybrid Vehicles

Hydrogen fuel cell technology is maybe years away from begin used in vehicles.  In the near term the most promising hybrids might be using the humble old diesel engine.  Diesel engines get about 30% more miles per gallon than gasoline which are real savings in any driving condition.  Diesel emits up to 20% less carbon dioxide that gasoline.  Diesel engines offer constant power for long periods while suffering less wear than gasoline engines and at the same time giving higher efficiency. 

Diesel electric hybrid vehicles are all around us.  Most trains are diesel electric hybrids.  Diesel electric buses are used in Seattle.  Giant mining trucks and some submarines are diesel electric hybrid vehicles.

Advanced diesel technology is here and ready to be used in hybrid vehicles. Diesel power will play a central roll in reducing emissions and fuel consumption using diesel electric technology.  Hybrid electric vehicles are powered by two sources.  In the case of the diesel electric hybrid vehicle it is powered by a both a diesel engine and an electric motor. 

The diesel engine in a diesel hybrid vehicle is tied to a generator which generates electricity for an electric motor or batteries and/or super capacitors to store electricity of use later in the electric motor.  Removing the need for a separate transmission for the diesel engine increases the efficiency of a hybrid vehicle.  In some cases the diesel engine in addition to turning a generator also directly supplies power to the vehicle.  This is called a parallel hybrid vehicle. 

In a petroleum electric hybrid vehicle mechanical energy is transferred into electricity and then back into mechanical energy which normally decreases the energy efficiency.  What will bring diesel engines ahead of all other currently developed gasoline electric hybrid vehicles is a diesel hybrid electric vehicle is more energy efficient.

A conventional diesel powered vehicle requires a larger engine compared to diesel hybrid.  The diesel hybrid can use a smaller more efficient engine because an electric motor will be providing partial or total power to the vehicle.  The hybrid diesel when designed properly will operate the diesel engine only at the engine’s optimum power output and speed.  This works best in a hybrid serial application where the diesel engine is only used to power the generator.  When the engine is runs at its optimum lower emissions and increased fuel efficiency is the result.

The engine in a diesel hybrid can be temporarily shut off during idle or coasting when enough electricity is available to the electric motor to propel the vehicle.  This also reduces emissions and increases fuel efficiency. 

Regenerative Braking will add to the energy efficiency of a diesel hybrid. Regenerative braking collects the kinetic energy normally lost to heat when using friction braking by turning small generators which provides electricity for batteries and/or super capacitors.  This stored energy then can be used later by the electric motor.  The diesel engine usage is lowered to generate electricity.

Unlike hydrogen powered vehicle, a diesel hybrid vehicles can use be refueled at conventional fueling stations.  Diesel hybrids provide performance equal to conventional vehicles. 

Automakers are producing diesel engines that are quieter and cleaner every year.  The 2008 Ford heavy duty series diesel trucks will include the cleanest burning diesel engine of that class ever offered by Ford.  Chrysler’s Mercedes division has come out with their BlueTec diesel providing ultra low emissions.  The key for automakers profit is lower emissions.  Lower emissions mean more sales.

Learn More:  
Heavy Diesel Electric Hybrids
Diesel Electric Delivery Trucks
Relfex Diesel Hybrid

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