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updated 3/14/2011 2:10:33 PM ET 2011-03-14T18:10:33

 

Coming to the U.S. in 2011 is tiny techno-gadget that few Americans will recognize: The tiny Fiat 500 automobile. When it starts arriving on American roads it will be perhaps the most visible early effect of Italian automaker Fiat's takeover of the troubled Chrysler. Along with its corporate significance this little Fiat will bring with it some technical wizardry few American drivers or even car dealers have ever seen.

The Fiat 500 is a very small car even by European standards. At 139.6 inches (3546mm) in length it's six inches shorter than the already-diminutive MiniCooper. And like the MiniCooper, which in name, appearance, and spirit harkens back the iconic MiniCooper of 50 years ago, the Fiat 500 is the modern-day incarnation of a classic 1950s Fiat mini-car. The original Fiat 500 was so named for its tiny engine, a 500cc two-cylinder motorcycle-sized engine that made the car slow but also cheap and fuel-efficient, just what was needed in Italy's post-WWII economy.

The new Fiat 500 is substantially larger than its 1950s namesake and, though still called "500" its engine is considerably larger than 500cc. But just like the re-born MiniCooper, in appearance and style the new Fiat 500 is remarkably reminiscent of its cult-idol ancestor. (In the animated film Cars the Italian tire dealer, Luigi, voiced by actor Tony Shalhoub, is a yellow 1959 Fiat 500.)

Technical wizardry

This stylish little Fiat will bring with it some innovations virtually unknown on American roads. One of them seems at first impossible: It has no throttle. It has a gas pedal, but no true throttle per se.

In a gasoline engine the " throttle " is well-named: It's a valve that progressively opens or closes the air intake to the engine, thereby "throttling" (choking down) the flow of air so the engine produces only the amount of power the driver requires. Whether the engine has an old-fashioned carburetor or modern fuel injection, opening or closing this valve (via the gas pedal) is how the driver "opens up" the engine for more power or "throttles down" for less power. But the Fiat 500 has no throttle valve at all. The air intake is always wide open and unobstructed.

Driving with no throttle

Instead of a throttle valve the Fiat 500's engine computer detects the position of the gas pedal and uses little electric motors to adjust each individual engine valve (four per cylinder, two for intake and two for exhaust, sixteen altogether) so that the engine itself only sucks in just enough air and injects just enough fuel to provide the amount of power the driver is requesting. It's a Fiat innovation known as "MultiAir" and it's very clever, but it's not done for the sake of cleverness: By eliminating the obstruction and air turbulence caused by the physical throttle valve blocking the air intake it makes the engine more efficient, allowing it to deliver more power as well as better economy. While variable-valve technology has been seen on some other advanced engines (such as BMW and Infiniti) in recent years, none have the Fiat 500's ability to adjust each valve individually, a bit of technical sophistication that significantly enhances efficiency.

Power to burn

The little Fiat also incorporates two innovations that make the most of its small 1.4-liter engine. One optional feature, turbocharging, has been known for decades as a means to make use of otherwise-wasted energy -- the flow of exhaust gases -- to spin a tiny (hand-size) turbine to extremely high speed, sometimes reaching 100 000 rpm. The spinning turbine is directly connected to a compressor impeller on the other side of the turbine housing, which compresses the air going into the intake of the engine. By compressing and forcing more air (and therefore more oxygen) into the engine it's able to burn more fuel and therefore producd more power.

This gives the small 1.4-liter engine the power and feel of a much bigger engine, but without the extra weight, size, and low-RPM inefficiency of a larger engine.

The innovation in the 500's turbocharger is that it's a a variable geometry turbocharger, meaning the turbine blades are not fixed, but are variable in pitch angle, just like the vanes on large jet engines. Adjusting the pitch angle of the the turbine vanes allows the angle to be optimized for the speed of revolution so the turbocharger can provide high flow at low RPM while not creating excessive pressures at higher speeds. This ability to optimize the turbine vane angle allows the engine to have optimum turbo boost pressure, and therefore strong torque, at all RPMs. That ability to generate strong torque at all RPMs is what gives this small engine the feel or a larger engine.

The turbocharger is an option on the Fiat 500 and on the American version it bumps the engine's output from 100 horsepower to 170 horsepower -- a huge increase in power. Combined with the Fiat's very light weight (about 2200 lbs / 1000 kilos, compared with about 3600 lbs / 1600 kilos in a typical family car), the 70 percent boost in power dramatically alters the feel of the Fiat 500 from that of an economy car with adequate power to a very quick little coupé. Those who have driven the turbo version report it feels like a little sports car, its agile performance belying its soft, rounded teddy-bear shape.

Something for nothing?

Another innovation used in the 1.4-liter engine, direct fuel injection, is relatively new and seems to provide something for nothing. Previous fuel-delivery systems, both carburetors and conventional fuel injection, mixed gasoline with air inside the air intake, creating a sort of gasoline fog, then allowed each cylinder to suck in some of the gas-fog mixture in each intake stroke. Direct fuel injection, however, injects a tiny jet of exactly the right amount of fuel at exactly the right time directly into the cylinder. This ensures optimum fuel delivery under all conditions and the result is both increased fuel efficiency and increased power.

But it's not quite something for nothing: To implement direct fuel injection requires a more sophisticated, more expensive fuel injection system (to operate a higher pressures and with injectors that can withstand much higher heat and pressure). It also requires smarter and faster engine computers that can make the millions of computations each second based on hundreds of engine-condition readings each second and precisely adjust and control thousands of injection cycles with microsecond precision.

The computer that does that is the same engine computer that simultaneously provides the microsecond-accurate control of valve positioning cited above, all based on simultaneous real-time sample of dozens of sensors hundreds of times per second, and manages in real time many other aspects of engine and transmission operation.

So if there's any real magic in the technical wizardry of the Fiat 500, it's not in the gears and valves, it's in the silicon and software that resides in a small, nondescript metal box that few will ever notice.

Champagne features on an economy budget

The combination of clever technologies that make the Fiat 500 a tiny technical marvel are not unique to the Fiat 500, though relatively few cars have them and fewer yet combine them all in one car. What is remarkable is that they have all been brought together in a very small, low-priced car. Though none others offer the same combination of technologies at the same price, some, such as the Volkswagen GTI and Mazdspeed3, though larger, more powerful, and somewhat more expensive, come close.

What all such cars point to is the future of gas-powered cars: Smaller, yes, but also more powerful, amazingly efficient, environmentally cleaner, and in many ways safer, all thanks to the huge gains and lower costs of computer power.

And not just in the computers in the car: Some of the advances in the Fiat 500's mix of technologies are possible only because of advances in super-computers and complex fluid dynamics and flame propagation computer simulations, which in turn have led to breakthroughs in understanding how the combustion process works. Those in turn have allowed the creation of software and hardware to implement new paradigms of how a gasoline engine should work.

And finally, one more trick

The Fiat 500 is being built in a Chrysler plant in Mexico for sale in the U.S. starting in 2011. But in 2012 Chrysler will unveil one more "trick" from the Fiat 500: An all-electric version. Chrysler has not yet released specs on it, but rumors are that it will be competitive with other upcoming small, all-electric cars such as the Nissan Leaf.

That would indicate a predicted range of at least 100 miles, capable of self-charging at any 120- or 240-volt outlet (faster recharge with 240 volts, but still several hours), and a price likely in the range of $30 000 to $35 000. How well it will sell is an interesting question: With the gasoline-powered 500 already very efficient and economical, will there be many willing to pay a premium of 50 percent or more, plus much shorter range and much slower fill-ups, just to go all-electric?

We'll see -- Fiat and Chrysler will certainly give it a try.

 

© 2012 TechNewsDaily

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