Hosted by IDTechEx
Electric Vehicles Research
Posted on June 22, 2012 by  &  with 3 Comments

Range extender arrays?

Paul Janson writes to us to say that he has applied for a patent on a new range extender concept based on arrays of range extenders. It is based on "a scalable charging system involving multiple independent combustion engine chargers that can be controlled independently of each other. The engines would be of small displacement thus decreasing fuel consumption and increasing total range of the vehicle. The system basically operates the chargers in parallel. The following invention would be using Rotary Engines but it could also utilize micro turbine engines or conventional piston driven generators."
He says that, "The invention consists of 2 or more independent onboard internal combustion engine electric generators capable of charging an electric vehicle battery pack. The Engines would operate independently of each other so that their operation could be controlled to conserve fuel. The engine generators could be of the same wattage and bore displacement or they could be of varying outputs and displacement. It would be a scalable charging system dependant on the power requirements.
The Generators could operate at different rpm depending on the vehicles charging needs. For example when the vehicle is stopped one generator could still be running and the rest could be shut down to conserve fuel. Another purpose of the invention is the sum total of the generators operating at full power would still consume less fuel than a large single engine generator. The way this could be accomplished would be to use small displacement highly fuel efficient engine generators.
Another way this invention could extend the range of the electric vehicle is by switching on only one engine as the battery starts to drain and as the battery continues to drain to switch on each successive engine at a point in time so as to enable the electric vehicle to go far beyond the range now dictated by current battery technology but still using as little fuel as possible and allowing the vehicle to get back to its charging station. The idea behind this is that as the battery starts to deplete the engine generator that comes on would cause the battery to discharge at a lesser rate and as the second charger comes on the battery discharge would be at an even lower rate and so on with the next engine powering up.
Another scenario would be where the driver selects a mode based on the distance they think they will drive. For instance if they know they can make a round trip within the batteries capability no charger engines would start and they would make it back to recharge and no fuel is used. If they change their mind somewhere on the road and go further they could override the initial choice. If they know they will go further past the battery capability say one engine charger could come on early to get them past the point of total discharge but just enough to get back to the charger station. This would conserve fuel because on the existing cars a multi cylinder engine starts up using more fuel. Another example where this might be utilized is in stop and go traffic on a freeway where fuel economy is greatly compromised.
At some point if the vehicle has finally expended its battery all the engines would be operating and the battery would be charging fully. Ultimately this array of engine chargers would allow for more flexibility and fuel efficiency. The engine array could be operated with computer hardware and software so that the optimum mix of charging power and fuel efficiency could be reached. The independent engines could be aggregated together physically so that they could share the same oil and cooling resources .This would also allow the engines a smaller more compact size. The engines can also be run on a variety of fuels such as gasoline, diesel, natural gas, biodiesel hydrogen etc."
At IDTechEx we are not too sure that this makes sense. Comments please.
For more on range extenders, read the IDTechEx report, Range Extenders for Electric Vehicles.
More IDTechEx Journals