 So what kind of strange looking car is that? The styling is definitely European, which makes sense seeing as how the inventor of this amazing thing is French, Mr. Guy Negre. Maybe you've heard myths about engines that run on compressed air, or maybe you've seen the ads in the back of Popular Science for things equally as out-of-the-ordinary. Either way, this car is definitely no myth and the inventor is one incredibly smart (French) cookie! Mr. Negre has spent much of his life working in the race car industry, building and tweaking engines for maximum performance. One day he decided to apply his knowledge to build something that doesn't pollute, and we're certainly grateful he did. HOW he did this is nothing short of genius. I've read the banter in virtual forums on how such a thing could never work, how hundred's have tried and failed, and how there's no way compressed air can store enough energy to run a car any farther than a few feet. Well, like most pessimistic poopheads that spend their lives spreading negative energy (dream stealers I call them -- the ones who'd like to see us continue in the dark ages of black smoke and lung cancer), they were WRONG! :)
Performance?...Now, to be honest, the aircar isn't going to solve the world's ground transportation problems. The acceleration performance is less than stellar, actually a bit like a diesel engine's performance. The engine's maximum of 50 horsepower pushes the car along from zero to 30mph in 7 seconds (with a re-acceleration time from zero to 30mph of 3 seconds) and has a top speed of 80mph. The car's range is about 124 miles per tank of compressed air, although it is less if you spend the entire time going 80mph.  With these figures it comes as no surprise that the target markets for aircars are taxis, delivery trucks, and small pickup trucks (although a family sized car is also planned for production).
How does the air-engine do it?...How did Guy Negre manage to get so much energy recuperation out of compressed air? Well, as he puts it, the problem with piston engines is that they try to accomplish everything in one cylinder. As you can see in the picture at the right, Mr. Negre splits up the cycles (intake-compression, combustion, expansion- exhaust) into three different chambers. Outside air is allowed into the compression chamber and is compressed to a very high pressure (about 290psi). At the highest point of pressure the air becomes very hot (400 C). At that point, air from the storage tanks which is stored at ambient temperature, is injected into the combustion chamber. Since the injected air is relatively much colder than the air compressed by the piston, the injected air is heated almost instantaneously causing a sudden expansion of the air into the expansion and exhaust piston, thus moving the piston and causing torque. It's also interesting to note that since the exhausted air has  expanded so quickly, it causes the temperature of the air to drop very low. Thus you can see in one of their videos how the exhaust air looks like steam, much like the condensed water vapor rising off ice-cubes. Additionally Mr. Negre (seen left with his engine) uses the cold air from an intermediate heat exchanger to provide air conditioning to the passenger cabin! According to the inventor, the engine is also easily configurable to run on combustible fuels such as natural gas, hydrogen, gasoline, etc.. He suggests that ideally the engine would run on compressed air at low speeds and switch over to the combustible fuel for higher speeds (an American version would most definitely need such an alteration). This would pose little added complexity since the air tanks are already rated to store hydrogen and natural gas. As an added benefit for range, Mr. Negre has also incorporated a mechanism for recovering braking energy and converting it to compressed air (ala regen braking on electrics and hybrids).
So how is it refueled?...So how do you refuel an aircar? With air of course! Each car comes with an onboard air compressor unit that plugs into a 110/220V outlet. The compressor puts out about 812 cubic feet of compressed air per hour. The onboard storage tanks hold about 3200 cubic feet of air @4500psi. This equates to a refill time of about 3.5 hours if using the onboard unit. A refill station, however, would use an industrial sized air compressor and could refill the tanks in about 3 minutes! The four hour refill time for the onboard compressor is comparable to the refill time for a natural gas vehicle using a FuelMaker compressor. The energy used to compress the air is about 19.25kWh. This is a fair amount of electrical energy and one of the factors under consideration in the downtown areas of Spain. However, consider that a hydrogen electrolysis/compressor unit takes about 60kWh to fill the same sized tanks with hydrogen (although a FuelMaker CNG compressor only uses 1.2kWh to fill a tank -- but it's not portable)! When one begins to consider the implications of using air as a fuel, it's immediately obvious the incredible advantages that compressed air offers. First of all there are absolutely no emissions! In fact, the air in the storage tanks is passed through a scrubbing carbon filter prior to injection. This means that the air coming out of the exhaust pipe is CLEANER than the air that went into the tanks! This makes the aircar a true ACE (Air Cleaning Engine). Secondly, the fuel (air) is completely non-flammable, non-toxic, and about as safe as any fuel could ever be. This means no need for fuel transport, no need for gas pipelines, no need for drilling or mining, and no expensive batteries to ever replace. Anywhere you go in this world, where there's electricity, you can refuel. When you consider that the air compressor can be run off of renewable energy, you can see that the entire energy/fuel cycle can be zero-emission!
What about availability?...So when will you be able to go buy one at the nearest car dealership? Well that depends on where you live. If you live in France or Spain then you should be able to purchase one sometime in 2001. You can expect to pay the US equivalent of about $14,000, which is amazing considering the cost of other alternative fueled vehicles (hybrids and fuel cell cars for between $20k and $40k). Mr. Negre's concept of car production plants is about as revolutionary as the car itself. It's almost a cross between a car dealership and a fast food chain. Factory licenses (franchises) are sold to whomever wants one but the stipulation is that it must be built and operated according to MDI's specs (Moteur Development International, Mr. Negre's company -- check out the English version too). To date, Spain, South Africa, and South America have bought all of the factory licenses.  Spain is further along than South America in implementation with an operational plant scheduled to open in the Summer of 2001. South Africa expects to be producing cars no later than 2003 (check out their quality website). The response to this car outside the US has been phenomenal. Upon seeing a demonstration, Mexico City ordered 40,000 cars to replace their aging and polluting taxi fleet! The car has immense potential for large polluted cities since it indeed cleans the air as it operates (although to be completely "green" it should be insured that renewable energy powers the compressors). SunWater has been in contact with the company in Spain (it helps to know a little Spanish) that is building the first factory outside of France. I actually received notice on the 6th of June that Spain will be the home of five new aircar factories/dealerships! They asked me to spread the word here in America in hopes of finding someone that will invest in building a factory and selling the cars here. Heaven knows we need the air-cleaning capability of this car! To be honest however, the car would need to undergo a few restyling modifications if it ever hopes to attract American buyers. But if the tiny two-seat Ford Th!nk battery-electric car, with a top speed of 60mph and a range of only 50 miles, can find a niche market here then certainly the better performing, less costly, and roomier aircar should be able to do as well! All interested parties should check out the web pages on the Green Links page and email the company for more information (it helps if you can write in Spanish or French). Vive el coche del aire!
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