Wednesday, December 10, 2008

The EXTERNAL Combustion Engine!

I first noticed this blog write-up about a week ago:

At first I didn't really pay attention to what the author was saying, but when further explained  the MDI Compressed Air Engine as an engine with a THERMODYNAMIC CYCLE, it actually began to make sense...

In essense, what Guy Nègre has managed to develope is the...


Basically, the fuel or heating source is completely external to the engine and acts as a pressure multiplier for the compressed air powering the motor itself. This means that the combustion process or heating process is continuous at lower temperatures and therefore an extremely efficient burn; almost all of the heat energy produced by the pre-burner will be used to expand the compressed gasses creating an increased power output per unit volume of compressed air. 

In the internal combustion engine, a pulsed fuel explosion creates extreme heat and exhaust vapor in each burn cycle. This "waste" heat and exhaust vapor is then completely purged from the system via the exhaust and cooling systems. This is why the efficiency of the standard internal combusion engine is so low! All of the heat energy is considered waste, but in the EXTERNAL combustion engine, heat is a fuel multiplier,  therefore a SOURCE of energy!


So, in essence, the system is similar to a regular engine, but one which heat is used as an input and not simply viewed as a by-product of the whole process... WOW!

*I realize that my explanation is an extreme oversimplification of the MDI engine theory, but that's how I wrapped my head around the whole heater/fuel concept.

Imagine an engine that's not an internal combustion engine, nor a complete external combustion engine like the steam engine, but a HYBRID compressed air AND external combustion engine... ASTONISHING!

*FlowAir = dual-energy engine!

Now, I can already hear people using the argument that we still need to fill the compressed air tank, and this takes energy.

True! But...

We could use our existing infrastructure for compressing air without taxing our electrical grid what-so-ever...  by charging the compressed air tanks at night!

Typical power grid demand (sample):

Notice how demand drops during each night and peaks midday. The thing to remember is that power generation does not stop; current power generating systems keep the grid availability above demand levels at all time, otherwise the grid browns out or fails outright. All of the available power being generated at night is simply wasted...

Apparently our current power generation is enough to charge a whole generation of electric powered vehicle during each night cycle, or perhaps built-in compressor units for each MDI powered vehicle. (imagine that!)

At any rate, it appears the whole concept of the MDI External Combustion Engine is a valid mechanism for replacing the current model.

I really hope to see these vehicles out in the market ASAP.

It's time for a change from the old status-quo... and remember...

"the future is air" - Guy Nègre


  1. When I viewed how Guy Negre's engine worked in animation, I already noticed the heater coil connected to the intake manifold. I was immediately amazed! It all made a lot of sense! Heat expands the air, letting more pressure into the cylinder. The result? More power! Great design!

    Although I wouldn't really use the term "combustion". The heat produced is more likely electrical rather than from any combustion process.

  2. Better read the MDI website:

    "In the case of dual-energy engines, an energetic adjuvant (petrol, diesel, oil, alcohol or gas) is burned in an external continuous combustion chamber."

    FlowAir = dual-energy engines. Now it really makes sense why they chose this design for high speed vehicles... excellent energy return on minimal heat input.

  3. Does MDI have any working models yet?

    Has any auto magazine ever been able to test any of the MDI prototypes to independently verify their operating range?

    MDI is great at press releases, but not so good at actually delivering what they claim.

    Virtually every year since 2000 they have announced production staring in 12-24 months, yet we are all still waiting for even one car to be built and sold!

    No explanations of what happened to the e.Volution car. No explanations of what happened to the Eolo car. No explanations of why they repeatedly take in additonal investor money and never deliver.

    Maybe this time will be different, but I'm not holding my breath.

  4. Review these Google results and they tell us why any of MDI's claims should be believed.

    What is amazing is that bloggers and journalists ignore history. We should learn WHY all of those promises weren't kept and try to avoid repeating that same problem.

    On the other hand, perhaps the problem is that MDI is not a car manufacturer. Their business model is to make money by selling licenses and franchises. In that business model good press is important, actually delivering a working product is secondary.

  5. Another anonymous comment... how very interesting...

    I would imagine that even a simple comment would at the very least deserve the courtesy of a pseudonym, or maybe even a valid Blogger ID.

    I will leave these comments here for now, but unfortunately all further comments will have to be moderated.

    Please attach a valid ID or email address to have new comments posted.

    Thanks; gnomædh

  6. Do you have any substantive response to the questions?

    For example, MDI says they made a pilot production lot of 11 CityCat 1 vehicles. What is the actual, tested autonomous range of those vehicles?

    Have they ever let an independent tester, such as an automagazine road test one of this pilot production run. A very basic check of performance, such as maximum speed, noise levels, operating range, etc ???

  7. DO you have any substantive response to the questions raised above?

    MDI says they have built a pilot production run of 11 CityCat 1 vehicles. Have these been tested?

    If they have been tested, what is the operating range?

    Has any independent person, such as a reporter for an auto magazine been allowed to road test one of the pilot production run? Have they been allowed to do the normal, simple road tests such as general observations on noise, acceleration, suspension; and quantitative tests such as maximum speed and operating range?

    If MDI has not let their pilot production run be observed and tested, why??? Is it a case where the actual performance is very much less than the claims?

  8. That's a valid question, Charlie. I really don't have a good solid answer for you, but please remember...

    The reason that I started this little blog in the first place was to make people aware that there are many potential technologies to replace the internal combustion engine, but most of them are ridiculed, squashed, bought-out by big competing industries, or blocked by government agencies. The GM EV1 is a prime example of this ("Who Killed the Electric Car") and so is the ZENN low-speed electric car built in Quebec, Canada:

    I guess the best that we can do is wait for the Auto Xprize run in the spring of 2009 to see efficiency related test data on the MDI dual-energy engine.

    On that note, good luck to all Xprize competitors and may the best CONCEPTS (*plural) replace the standard petrol engine, ASAP!

  9. If your goal is to make people aware of potential technolgies, independent of whether or not that company is an investment scam, then another company you should be making people aware of is "Magnetic Air Car, Inc" of San Jose, Calif, USA.

    The performance of their car is even most astounding and revolutionary than the MDI air car performance claims. Once the tanks of the Magnetic Air Car are charged, you nver have to recharge them as the car will do that itself while driving.
    "What we are building is similar to an electric car but with compressed air tanks instead of expensive rechargeable batteries that can only provide short driving distances. We believe our engineers have developed a solution for manufacturing air while the vehicle is in motion which may provide an unlimited driving range"


    "Eastwood: How are you able to keep the air car’s tanks filled?

    Parks: Our air tank system design supplies air pressure to our patent pending cold air bearing turbocharger and Air Cycle Machine™. We do not care about air flow since our motor creates enough pressure to drive any load. "


    Like, MDI, the claims of Magnetic Air Cars have not been independently verified.


Comments are always appreciated, yet moderated! All new comments will be reviewed before being posted, time permitting. Thanks ~ author...