#Talking Progress© Photo credit : Shutterstock
Hybrid trucks featuring jet turbines
|The expert : Ian Wright, founder and CEO of Californian company Wrightspeed, co-founder of Tesla Motors, developer of the X1, the world’s fastest electric vehicle.|
What’s the idea behind the turbine and electric motors?
Ian Wright: The turbine always rotates at the same speed. It’s about choosing the best speed for power generation by the generator so that it’s always operating at maximum efficiency. The batteries then act as a buffer, powering the electric motors, which drive the wheels, as needed. The key point is to drive the turbine at an optimal speed. Electric motors are more efficient in terms of adapting to load variations (acceleration, deceleration, etc.).
Another key point is reliability: there is almost no maintenance required for a turbine and electric motors. This represents a significant source of savings for a truck fleet. The third key point is pollution. It’s an excellent solution when it comes to meeting current and future standards. With our system, there’s no need for a catalytic converter to ensure compliance with Californian regulations.
|A truck fitted with the Route system. The two electric motors can be seen between the wheels. The braking energy recovery system is also located here. In blue, the lithium-ion batteries (from A123 Systems). Under the cab, at the front, the Fulcrum turbine sits where the heat engine would be. © Wrightspeed|
Why do you believe the solution is best suited to trucks?
The best results have been obtained with vans or delivery trucks, which have stop-and-go drive cycles. It’s this type of use that makes them so fuel-intensive. Our turbine, however, always rotates at the same speed. What’s more, our system recaptures braking energy. And a lot of it: the fuel savings generated are 10 times higher than those of a hybrid-powered vehicle. And don’t forget that the batteries can charge overnight: trucks are powered up to set off with a range of 45 kilometres. The system is ideal for refuse trucks, which make frequent stops. We are already fitting out fleets of this kind in the US.
Why has no one thought of it before?
The difficulty lies in producing a small turbine that is both powerful and efficient. Small models are single compressors, and efficiency is inadequate. But the Fulcrum turbine has two compressors, that's what's new!
|The secret is in the Fulcrum turbine|
Whatever you do, don’t tell Ian Wright that his company sells hybrid engines. His two products, Route and Route HD, are range-extended powertrains powered entirely by electricity. That’s where the future of electric vehicles lies, at least in the medium term, according to Ian Wright and many car experts. Several methods are being explored, such as hydrogen. The Wrightspeed solution is a small proprietary turbine, named Fulcrum. It’s a combustion turbine like those that drive jet engines or turboprop propellers. It can run on fuel of different kinds, such as kerosene or biofuels. The idea of adapting this type of engine goes way back. Renault’s famous “Étoile filante” (Shooting Star) car broke the world speed record in 1956, reaching 308.85kph over five kilometres. But turbines are heavy, costly and poorly suited to a normal car’s variations in power.
However, if they run at a steady or almost steady speed (100,000 revolutions per minute in the case of the Fulcrum), their reliability far outweighs that of a piston engine. That is why they are so commonplace in aviation. They are already being used to generate power, especially in airliners’ auxiliary power units, which supply on-board electricity.
The key to it all, and this is what Ian Wright, a passionate mechanic who has worked with Lotus engineers, has discovered, is to produce a small turbine with two compressors to give it optimum power and efficiency. According to Wrightspeed, fuel consumption is 50 to 60 percent lower than a conventional heat engine.
You are not selling trucks or cars but a powertrain. Why?
I’ve been with Tesla Motors. I know what’s involved in designing a car. It’s very complicated! Wrightspeed is selling a simple solution: you bring in a truck whose engine needs to be changed (which fleet managers regularly do) and we will replace it for you with our Route (for 5 to 13 tonne models) or Route HD system (for heavier models). We will also sell these solutions to companies that assemble trucks.
|Diagram of the Fulcrum turbine. It weighs just 113 kilogrammes and generates 80 kW (108 hp). The rotating parts are on the left. The two pipes are connected to the cooling system and sit on either side of the electronic controller. © Wrightspeed|
Can the solution be used for cars?
Yes, the powertrain can work in a car, but it is the most economically compelling for heavy and medium duty trucks with a hard drive cycle, so we're focused on meeting those market demands.
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