New Wrightspeed Micro-turbine Range Extender Introduced



The new Wrightspeed micro-turbine range extender is 30% more efficient than any existing turbine powered generator. Wrightspeed is a start-up created by Ian Wright, one of the co-founders of Tesla Motors. He disagreed with the way Elon Musk was running the company, so he cashed in his stock and walked away. That decision cost him millions. That’s just crazy, right?

Crazy like a fox, maybe. He founded his own company called Wrightspeed to produce electric powertrains for heavy duty vehicles — like garbage trucks. Wright says his each of his trucks can save fleet operators as much as half a million dollars over its useful life, thanks to lower fuel and maintenance costs.

The Wrightspeed micro-turbing range extender generator is a cutting edge new design. Named Fulcrum, the 80 kW unit uses a two stage compression process and a novel recuperation design that makes it 30% more efficient while tripling usable power according to Green Car Congress. The turbine can run on diesel, CNG, LNG, landfill gases, biodiesel, kerosene, propane, heating oil, or any other combustible fuel.

Turbine technology has been tried in automotive applications before, but the results were always disappointing. Turbines are not well suited to the changes in operating speed required by stop and go driving. The key to the Fulcrum micro-turbine is that it operates only at its most efficient speed of around 100,000 rpm. To increase efficiency, the Fulcrum recovers a portion of the exhaust heat by using a heat exchanger called a recuperator to increase the energy of the gases entering the expansion turbine. “Without a recuperator,” says Wright, “efficiency is just horrible.”

The Fulcrum micro-turbine generator weighs far less than a traditional piston engine powered generator. It’s exhaust is so clean, it requires no catalytic converter to meet California’s stringent emissions standards. Weighing just 250 lbs, the Fulcrum has a remarkably high power to weight ratio of 750 kW per kilogram. It has also been designed to be affordable by minimizing  manufacturing costs.

Wrightspeed emphasizes the use of high-power batteries rather than high-energy batteries in its powertrain. Says Wright:

One of the things that enables the story is that the batteries have become extremely reliable and long life, even when at high power. We use the smallest pack we can. In general, we save fuel in three separate ways: first is with a grid charge; second is regenerative braking—we run very high power regen, much, much higher than anyone and we pretty much avoid the use of friction brakes; and third is running the engine at the sweet spot.

Elon Musk’s quest is to build high performance cars for the fortunate few. Ian Wright’s mission is to make the vehicles that pick up our trash and deliver our packages as efficiently as possible in order to dramatically reduce the amount of carbon dioxide they add to the atmosphere each year. Musk gets all the headlines, but which man is making the more important contribution to the environment?

About the Author

I have been a car nut since the days when Rob Walker and Henry N. Manney, III graced the pages of Road & Track. Today, I use my trusty Miata for TSD rallies and occasional track days at Lime Rock and Watkins Glen. If it moves on wheels, I'm interested in it. Please follow me on Google + and Twitter.
  • Dave Oh

    So let me get this straight: with a power-to-weight ratio of 750 kW per kg, this 80 kW power plant would weigh a little over 100 grams? Sign me up!!!

    • Joe Viocoe

      That isn’t how it is calculated.

      There are minimums. And it means that any additional power, would increase the weight by that much.

      • Dave Oh

        I know how power-to-weight ratio is calculated, and it is as I have calculated it, as is defined and evaluated in the industry. What you described might be called a “marginal” power-to-weight, but the way it has been stated in the text without additional context, this is not it.

        • Dave Oh

          Having said that, reading the GCC article linked above, it’s a typo in this article – GCC quotes the power-to-weight ratio at 750 W – not kW – per kg, a much more plausible value.

      • GrumpyCat

        What part of kW/kg * kg do you not understand the kg’s cancel leaving only kW? Are dimensional units not taught in Common Core? 30 years after graduation it has proven to be the single most useful thing I learned in Engineering school.

    • Shane 2

      According to Wright in an EVWorld podcast the average electricity usage across the work cycle for a garbage truck is around 40 kW, if you include regen braking. The 80 kW turbine gets max efficiency when run at only 50 kW. The plan is to keep the battery topped up with 50 kW turbine output. When the battery gets to a set % of max charge, the turbine cuts out. There is no point in running the turbine at lower than optimum 50 kW output when you have a battery buffer system.

  • BlackTalon53 .

    So what is the actual efficiency of the turbine running at the sweet spot? better than the 43% demonstrated by the Achates opposed-piston engine prototype?

  • John Hansen

    “Musk gets all the headlines, but which man is making the more important contribution to the environment?”

    Musk, because I see Teslas on the road every day, but never a Wrightspeed.

    • You won’t see a “Wrightspeed” … I think he just does powertrains that other people use.

  • James

    “Elon Musk’s quest is to build high performance cars for the fortunate few”. Well we know that this is wrong. Elon stated from Day One that his quest is to have (not necessarily make) affordable EVs for the masses. The only way to get there is from using the higher priced models (Roadster, Model S) to finance the lower priced ones (Model 3). And he is right on track.

    As for Wrightspeed – It is all good. Solutions are urgently needed for all weight classes. Tesla, VTrux, Wrightspeed and others.

  • J_JamesM

    “Without a recuperator,” says Wright, “efficiency is just horrible.”

    So essentially what they’ve done is build an external combustion engine, with an actual turbine as the heat source. Clever, I say.

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  • jburt56

    How about ultracapacitors?

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  • The future has arrived in auto tech. I have long thought that the best application for a gas fired turbine is to power an electric generator as turbines are their most efficient at a constant speed. Now it is here and it works. This is exciting. It want to see diagrams on how it is designed.