Video: 30 Years Ago The Stirling External Combustion Engine Was Tested By The Government – Where Did It Go?


Video: 30 Years Ago The Stirling External Combustion Engine Was Tested By The Government – Where Did It Go?

We’ve heard of the Stirling External Combustion Engine before but we never knew that they were not only built but also used and tested by the US Government, specifically the Department of Energy. These “external” part of the engine means that the combustion is not happening in the cylinder but rather outside of it. The heat from the combustion is used to move the piston. Weird? Hell yes it is but according to this video, which is admittedly slanted in favor of the potential manufacturer of the engine, the thing beat any and all expectations. It raised fuel economy, exceeded emission standards without the use of a catalytic converter or other device, and gave trouble free service in a multitude of different locations and environments.

If there is ONE part of the video that raises an eyebrow it is the fact that the narrator says that the tchnology exists to put the engines into “limited production” today. We’re not sure why they would be “limited” in their production but there are a few potential reasons. The first would be advanced and complicated machining, thes second would be construction from hard to find materials that are not easy to source. Outside of those limiting factors we’re not sure what the blockage was with these. We’re also not sure why the government did not move forward with more.

Either way, this video is cool because it shows off the testing and talks about these engines being used in the real world, something we never knew happened!

Watch this wild 1992 video about the Stirling External Combustion Engine –


  • Share This
  • Pinterest
  • 0

20 thoughts on “Video: 30 Years Ago The Stirling External Combustion Engine Was Tested By The Government – Where Did It Go?

  1. Matt Cramer

    My guess is that it ran into the same problem with turbine engines – lousy throttle response and only delivering their promised fuel economy when ran at full power.

    1. Steve Wilkinson

      If youook up Stanley Mayer hydrogen engine…you will be impressed…I’ve studied his work closely

      1. Tony

        He was a scammer, ended up in court over false claims. A university professor evaluated his prototype for the court, and said it we just running off the very small battery, generating Hydrogen for combustion. Had a range of about 1 mile.
        In the end he was order to pay damages, didn’t, then dissappeared forever.
        You need to study Engineering not the work of scammers, then you will see what a lot of rubbish it was.

      1. Gomez Carcajou

        That is an internal combustion Wankel engine with plenty power, but lousy fuel economy and difficult to reduce emissions notwithstanding a chronic seal problem leading to excessive, high cost maintenance.

  2. big john

    small stirling engines are sold as kits on sales sites they are really pretty neat engines not overly complicated there is one you put on top of your wood stove and it runs a fan

  3. Pat Bergfalk

    External combustion engines have been around since the 1800’s. Mostly used to pump water.

  4. Darren Kornowske

    The Sterling engine was developed in 1816 I believe. A very simple engine with less technology to build than the internal combustion engine a hybrid vehicle. This engine can be combined with encapsulated salt tubes which are heated with infrared heat tubes to create free heating and cooling systems for your house and the hot side of the Sterling engine can be in your salt block to create the heat to run the engine which hook to a generator will produce all of your electricity for free as well.

    1. Michael Moyle

      It looks like the issue comes down to the cost of higher-temperature tolerant materials and the size of radiators to dissipate the required heat (I *DID* wonder why they replaced the pickup truck’s 95hp IC engine with a 75hp Stirling when surely comparing like to like would be a better test. Presumably a larger, higher-powered engine and the radiator needed to cool it wouldn’t have fit in the existing engine compartment.)

      According to Wikipedia:

      Disadvantages of Stirling engines compared to internal combustion engines include:

      Stirling engine designs require heat exchangers for heat input and for heat output, and these must contain the pressure of the working fluid, where the pressure is proportional to the engine power output. In addition, the expansion-side heat exchanger is often at very high temperature, so the materials must resist the corrosive effects of the heat source, and have low creep. Typically these material requirements substantially increase the cost of the engine. The materials and assembly costs for a high-temperature heat exchanger typically accounts for 40% of the total engine cost.[72]

      All thermodynamic cycles require large temperature differentials for efficient operation. In an external combustion engine, the heater temperature always equals or exceeds the expansion temperature. This means that the metallurgical requirements for the heater material are very demanding. This is similar to a Gas turbine, but is in contrast to an Otto engine or Diesel engine, where the expansion temperature can far exceed the metallurgical limit of the engine materials, because the input heat source is not conducted through the engine, so engine materials operate closer to the average temperature of the working gas. The Stirling cycle is not actually achievable, the real cycle in Stirling machines is less efficient than the theoretical Stirling cycle, also the efficiency of the Stirling cycle is lower where the ambient temperatures are mild, while it would give its best results in a cool environment, such as northern countries’ winters.

      Dissipation of waste heat is especially complicated because the coolant temperature is kept as low as possible to maximize thermal efficiency. This increases the size of the radiators, which can make packaging difficult. Along with materials cost, this has been one of the factors limiting the adoption of Stirling engines as automotive prime movers. For other applications such as ship propulsion and stationary microgeneration systems using combined heat and power (CHP) high power density is not required.[39]

  5. John Koloski

    I have a stirling engine powered refrigerator. The Stirling engine is used to pump heat. A DC electrical solenoid motor moves the Stirling engine, which pumps heat out of an insulated box. Google TwinBird Stirling Cooler.

  6. Britten

    You missed the point of the limited production statment. They can build as many as they want. However they can build them at low valume and still remain competitive cost wise. They don’t need to build millions to get the cost down.

  7. Paul

    They probably had a few catastrophic explosions since the working pressure would have been in the order of 1000 psi +

  8. Bob

    From a test by a leading automotive company the Stirling engine they build showed minimal wear. So from that, I guess it would last too long, longer that the car would last. So, they killed it.

Comments are closed.