by Brett Davis

BMW has announced it is working on Turbosteamer and Thermoelectric Generator (TEG) technologies that aim to make better use of the energy that is lost as heat in combustion engines and exhausts.

According to BMW, up to 60 per cent of the energy created by an internal combustion engine is lost in heat, with half of it going to exhaust heat and the other half going to the cooling system. BMW’s EfficientDynamics engineers are working on systems which will capture this heat energy and turn it into electrical energy.

The electricity stored from this process will be able to provide power for various external accessories of the car, putting less strain on the petrol engine and reducing overall fuel consumption and emission levels.

The Turbosteamer is essentially a miniature gas turbine generator that will use the heat from the exhaust to create steam and in the process, turn a gas turbine. Team leader for thermal energy converters at BMW Group Research and Technology, Jürgen Ringler, explains,

“A heat exchanger recovers heat from the engine exhaust, and this energy is used to heat a fluid which is under high pressure – this heated fluid then turns into steam, which powers an expansion turbine that generates electrical energy from the recovered heat.”

As for the weight and likely production forecast, BMW says it should have a Turbosteamer system up and running ready for production in around 10 years. BMW says the system would only add around 10 to 15kg to the car’s weight while providing enough electric power to run all auxiliaries during highway and country road driving conditions. This would free up the engine reducing fuel consumption by “up to 10 per cent”.

Meanwhile, BMW is also working on Thermoelectric Generator (TEG) technology which, similarly, works by converting heat energy into electrical energy. A TEG will convert heat directly into electricity, similar to the way space probes are powered. NASA developed the technology, also known as Seebeck Effect, and has been using it for more than 40 years.

TEGs take the principal that an electrical charge can be created between two thermoelectric semiconducters that have different temperatures. Recent improvements in materials have increased efficiencies of the technology and opened it up to a range of new possible applications, such as in the automotive field.

In 2008, BMW released a TEG system integrated into an exhaust system that was capable of generating 200 watts. BMW says improvements have since been made in increasing overall efficiency of TEGs and says the company is now reporting power levels of up to 600 watts – or a bit less than what is required to power a small microwave oven. BMW says 1000 watts is just around the corner.

BMW says fuel and emissions reductions of up to five per cent are already accessible, and that for every 250 watts generated, a two per cent increase in fuel efficiency and a two per cent drop in emissions can be achieved.

As mentioned, these technologies are still under development but could be ready for production in around 10 years. It may sound complicated but if there’s energy being wasted, surely harnessing it and returning it back through the car is a good thing.

What do you think? Well done to BMW, or should more development be poured into hybrid and EV research instead?

  • Force-15

    This is old news, but it’s good to see that BMW are still developing this technology.

  • Eric

    Cruise liner have a crud version using the heat from the exhaust and engine water to run other things on the ship.

    I had an engine room tour on the Splendor of the Seas last year.

    but I forget how much energy (in %) they re-captured

    • davie

      Its not a new concept but I congratulate BMW for pushing the envelope and increasing efficiency.

      I remember reading about the Titanic that used a turbine to re-use the exhaust steam from the main two engines which otherwise would have been lost. That is why the Titanic had a 3rd (much smaller) propeller.

      • Oh Well

        I seem to recall the Titanic sank.

  • Nick

    You could even stick little Stirling engines on the exhaust manifolds. – at 12.5% efficiency for an average petrol engine, it would be hard to think of ways to make it LESS efficient !

  • Z

    Nothing from BM. All marketing.

  • fbholden

    Why don’t they have a normal turbo spinning a generator instead of forced air in the inlet manifold?
    I’m sure there’s a reason as it seems too simple of someone not to have come up with that one before.

    • Hugh Jorgan

      A “turbo” places a restriction in the exhaust. I can only guess the inefficiency of the restriction in the exhaust overrides the generator output.

    • MK

      Not a lot of energy, low mass flow rate.

    • Freddo

      Because its using the heat and not the exhaust pressure

    • AS

      Why can’t we attach electric generators to the wheels of an electric car and have them recharge the batteries. Then there will be no need to plug them in to a power point?

      • LastCommentIsVerySmary


  • Shak

    Why not. BMW have the cash and know-how to do it, and anything that improves fuel efficiency in ICE cars is a good thing.

  • Charger

    I look forward to BMW’s new Steam powered Range id love to try out a 520S :)

  • Jacob

    Could they use the heat to distil water?

    That would be great in Adelaide or 3rd world countries.

  • Ben

    ok. Good idea.. anything as has been said, that improves efficiency has to be a good thing. But, am I the only one that look at this and went 10 years??? Really 10.

    Maybe it is just me?

  • scatman

    I have been working on a huge steamer for sometime. almost time to release it to the public

  • Prasanthgopal578

    i lik  tis working system….

  • Dave Borrelli

    I think that this technology, coupled with hybrid electric technology is a very useful wa to increase effieciency from the ICE used in almost all automotive applications. Even a Prius or Chevy Volt still to some degree relies on an ICE. That means they still use a power source that dumps most of it’s energy out the tailpipe and cooling system. So this technology could be used to impove effiecincy for any ICE application. Imagine an across the board increase of uel economy on the order of even just 5-10%? That means 18 wheelers, SUVs, Pickups, Vans, Sedans, Hatchbacks, Sports Cars, etc, gasoline or diesel, conventional or hybrid, all improving 5-10% or more. This is a very worthwhile pursuit.