Can We Rebuild the NASA Stirling Engine Car?

I am certain NASA continued with Stirling engine development and design work (it is a cycle) with an eye toward incorporating electric generator with engine, and succeeded.

NASA Stirling converter generator

55% Carnot efficiency, fixed operating frequency by design. Can obviously run on solar, nuclear heat, fuel combustion, etc.

With this improvement, the car engine should be much simpler to build unless running on nuclear pile for heat, then the lead would make engineering a bit challenging.

Electric drive to the wheels, light weight frame, etc. The 45% waste heat is still available for cabin comfort, (cooking lunch), etc.

If you look at the older design, there are issues in fabricating the many passages for the regenerator and the cooler design is slightly cumbersome to fabricate as well, although these could possibly be done with additive manufacturing (3D printing).

Nice catches on the two videos. That one hour build is a complete hoot!

https://sites.suffolk.edu/agarciadelis/2014/03/06/67/

Great for desktop toy....

https://www.astro.uni-koeln.de/node/331

..."Tests conducted with the 1979 AMC Spirit, as well as a 1977 Opel and a 1980 AMC Concord revealed the Stirling engines "could be developed into an automotive power train for passenger vehicles and that it could produce favorable results."^[8] However, progress was achieved with equal-power spark-ignition engines since 1977, and the Corporate Average Fuel Economy (CAFE) requirements that were to be achieved by automobiles sold in the U.S. were being increased.^[9] Moreover, the Stirling engine design continued to exhibit a shortfall in fuel efficiency^[9] There were also two major drawbacks for consumers using the Stirling engines: first was the time needed to warm up – because most drivers do not like to wait to start driving; and second was the difficulty in changing the engine's speed – thus limiting driving flexibility on the road and traffic.^[10] The process of auto manufacturers converting their existing facilities and tooling for the mass production of a completely new design and type of powerplant was also questioned.^[9]

The MOD II project in 1986 produced one of the most efficient automotive engines ever made. The engine reached a peak thermal efficiency of 38.5%, compared to a modern spark-ignition gasoline engine, which has a peak efficiency of 20-25%. The Mod II project replaced the normal spark-ignition engine in a 1985 4-door Chevrolet Celebrity notchback. In the 1986 MOD II Design Report (Appendix A) the results showed that highway gas mileage was increased from 40 to 58 mpg_-US (5.9 to 4.1 L/100 km; 48 to 70 mpg_-imp) and achieved an urban range of 26 to 33 mpg_-US (9.0–7.1 L/100 km; 31–40 mpg_-imp) with no change in vehicle gross weight. Startup time in the NASA vehicle was a maximum of 30 seconds,while Ford's research vehicle used an internal electric heater to quickly start the engine, giving a start time of only a few seconds. The high torque output of the Stirling engine at low speed eliminated the need for a torque converter in the transmission resulting in decreased weight and transmission drivetrain losses negating somewhat the weight disadvantage of the Stirling in auto use. This resulted in increased efficiencies being mentioned in the test results.^[11][12]

The experiments indicated that the Stirling engine could improve vehicle operational efficiency by ideally detaching the Stirling from direct power demands, eliminating a direct mechanical linkage as used in most current vehicles. Its prime function used in an extended-range series electric hybrid vehicle would be as a generator providing electricity to drive the electric vehicle traction motors and charging a buffer battery set. In a petro-hydraulic hybrid the Stirling would perform a similar function as in a petro-electric series-hybrid turning a pump charging a hydraulic buffer tank. Although successful in the MOD 1 and MOD 2 phases of the experiments, cutbacks in funding further research and lack of interest by automakers ended possible commercialization of the Automotive Stirling Engine Program.^[5]"...

https://en.wikipedia.org/wiki/Applications_of_the_Stirling_engine

Stirlings are one thing, external combustion with 2500 psig steam is quite another, and in these, it is possible to have a suitable dynamic range of engine output. I don't know what became of cyclone power (www.cyclonepower.com), but it seems they had the concepts down. Perhaps there was an issue with water liquid film on teflon as lubricant, no oil.

True, you could have a full head of steam taking off when the light changes. But I'm wondering how soon you can start off from a cold start in the morning.

Maybe a steam/electric hybrid might get you going right away, with just enough batteries needed to run until the steam pressure builds up.

I do believe they ran tests on their engine at -30 F, and it was designed to recycle heat to that out the condensate tank/pump/lines, and warm up to full head of steam in 60 seconds.

IF that is not good enough, certainly there is the option of using electric heater with breakaway connection, so you just jump in and drive off instantly.

Normal above freezing conditions, the warm up is less than 30 seconds. I have to warm up my normal ICE at least 1 minute in the winter, due to thick oil, and probably the wrong oil filter (one without a dern check valve from the cheap A$$ oil change place.).

Interesting video about the blue pickup truck, kinda of reminded me of a Walt Disney video of jiminy cricket.

Geez, 50 mph top speed, " cool and clean exhaust ", meets emissions standards, maybe in 1985.

NASA getting into the car engine business,,, they must of thought there wasn't much of a future in the rocket flying business.

Why wasnt this further experimented ? I reckon todays cars are much lighter, and we could fit a stirling into a 'smart car' in a similiar way NASA did.

They are using them for spaceship power generators....

https://tec.grc.nasa.gov/rps/stirling-research-lab/advanced-stirling-convertor/

I feel that a modern "Plug in" Hybrid car is a far better choice if you are looking for efficiency and good MPG....

The Mitsubishi does well over 150 miles per gallon (Imp). See here:-

Mitsubishi outlander-phev