Have your HP and pass the pump!
Today's consumers are hungry for horsepower and thirsty for fuel economy. The problem facing auto manufacturers is more power usually means lower fuel economy.

In the past, automakers have tried supercharged or turbocharged engines as a way of melding the craving for horsepower with the demand for fuel efficiency. The problem with super- or turbocharged engines is a Jekyll and Hyde personality-lots of power or lots of economy, but not a happy medium.

GM's Displacement on Demand V8s include a solenoid control valve and a collapsable rocker that deactivates valve actuation to transform a powerful V8 into an economical 4-cylinder in an instant.

As a result, many manufacturers are turning to technology to produce more-efficient engines. One avenue that's in current favor is the variable-displacement engine. The theory follows: Use all cylinders for maximum power and half of the cylinders when cruising or in deceleration to save fuel. A variable-displacement engine essentially converts a V8 into a four-cylinder or a V6 into a 3-cylinder when power is not in demand.

According to John Biel, Editor-in-Chief for Collectible Automobile magazine, Cadillac offered variable-cylinder displacement in 1981 on its V8 engine. Called the "8-6-4," the unique engine was developed by Eaton and could run in 8-, 6-, or 4-cylinder mode depending on power demand. The engine was costly to produce and had numerous mechanical problems. It lasted only one year.

Fast-forward 20-plus years: Engines have gotten more advanced, electronics are now computerized, and horsepower is still king. Enter modern variable-displacement engines. General Motors, Chrysler Corporation, and Honda currently offer vehicles that sport engines with variable-cylinder displacement.

The biggest hurdle facing today's engineers is how to operate in two cylinder modes and maintain clean tailpipe emissions. The best way to do that is to close the valves on any cylinders that are deactivated. Though this sounds simple, it's not. However, that's where computers and technology come to the rescue.

In all variable-displacement engines, the intake and exhaust valves of the deactivated cylinders are kept closed by using computers and advanced hydraulics. According to Nick Richards at GM Powertrain, "This reduces pumping losses and helps ensure clean tailpipe emissions." GM calls their variable-displacement system Displacement on Demand (DOD). It is available on V8 versions of the Chevy Trailblazer, Buick Rainier, and GMC Envoy. In 2006, DOD availability will expand to include some V8-powered versions of Chevy and Pontiac cars and other V8-powered SUVs.

Chrysler also offers variable-cylinder displacement in the passenger-car version of its Hemi V8 engine. Called Multi-Displacement System (MDS) it is found in the Chrysler 300, Dodge Charger, and Dodge Magnum.

Honda offers variable-displacement on the V6 engine offered in the top trim levels of its Odyssey minivan. Because this V6 operates in 3-cylinder mode at times, Honda had to come up with unique electronic engine mounts to quell vibrations and employ active noise cancellation to reduce engine noise.

As consumer demand for more-powerful and more-efficient engines grows, expect to see variable-displacement in more and more engines.

Leave your CDs at home
Just when you thought you had it all figured out, here comes another new technology designed to make your ride time more enjoyable. You've heard of high-definition television, now there's HD Radio.

Consider the quality difference between a cassette tape and a CD. Well, supporters of HD Radio claim that AM will sound like FM and FM sound like a CD. In addition, HD Radio offers data-streaming. Broadcast along with the audio signal, this data stream could warn drivers of weather or traffic alerts or it could contain programming, song, and artist information.

In theory, HD Radio works exactly like conventional radio. Analog sound, digital sound, and data, however, can all be sent out in the same signal. Click on image to enlarge.HD Radio is the only standard for radio broadcasts that has been approved by the FCC, and a company called Ibiquity Digital (http://www.ibiquity.com/) holds the rights to licence the technology to radio stations and equipment manufacturers. According to Vicki Stearn at Ibiquity Digital, "there are more than 318 stations coast-to-coast that broadcast in HD Radio and will be more than 2,200 within three years."

Currently there are three aftermarket suppliers that produce car radios with the ability to receive and decode HD Radio: Panasonic, JVC, and Kenwood. But more are coming. In addition, Stearn claims that within two years auto manufacturers will be selling vehicles with HD Radio-capable head units. One advantage HD Radio has over satellite radio is that no special antenna is required.

Racing to the street
In NASCAR racing the phrase has always been, "Win on Sunday, sell on Monday." But that's because it was supposed to be stock-car racing. Even though the only thing stock about a NASCAR race car today is the decal on the fender, the phrase still rings true. In NASCAR they race a facsimile of the Dodge Charger, Ford Taurus, and Chevy Monte Carlo that you can buy in the showroom.

The front row for the 2005 Indy 500 features the the red-and-white Toyota of San Hornish flanked the Hondas' of Scott Sharp (left) and polesitter Tony Kanaan (right).

One strictly American form of racing where the vehicle technology translates directly to the road is Indy Car racing. Today, advanced overhead-cam V8 engines power the cars that compete at the Indianapolis 500. These engines, though highly tuned, are similar to the V8 engines found in larger cars, SUVs, and sports cars on the street.

With the end of May and the arrival of Memorial Day weekend comes the pinnacle of Indy Car racing: The Indianapolis 500. This year, cars powered by the Honda Indy V8 dominate. But wait, Honda doesn't have a V8 passenger-car engine, so how can the technology applied to this engine translate to your street car?

According to Robert Clarke, general manager of Honda's racing programs in the United States, "Honda racing culture runs very deep, starting with Mr. Honda who was a racer, engineer, and mechanic. Today, Honda uses its Indy Car and Formula One racing programs to achieve three goals. One, to develop people. Two, to develop technology. Finally, to promote the Honda name."

Honda's powertrain engineers are cycled through the Indy Car and Formula One engine programs. This gives Honda engineers a better understanding of how engines operate in extreme situations. How certain metals perform and what happens when things break. Perhaps the most noteworthy improvement for passenger cars to come from racing programs is variable-valve timing or VTEC. By constantly adjusting the intake and exhaust valve openings, the engine can be more powerful at high RPM and still deliver the low-pulling torque American drivers expect.

When Honda engineers return to their normal jobs, they take the knowledge gained in their experiences with the racing program and apply it to passenger-car and light-truck engines, making them more powerful, more efficient, and more reliable. And sure, it helps when Honda can advertise another Indy 500 win come Monday.

Skipping the middle man
Today, nearly every engine that powers a passenger car or light truck is fuel-injected. Not so 20 years ago. At that time, many engines still utilized a carburetor to mix the fuel and air an engine burns to produce power. But, much like the carburetor faded into oblivion, so to will fuel injection.

It will be replaced by direct injection. In a fuel-injected engine, the fuel is squirted into the air stream of the intake runner that leads to the cylinder. In a direct-injection engine, the fuel is injected directly into the cylinder.Direct injection allows for precise control of the fuel/air mixture. This allows engineers to tune the engine for more power, better fuel economy, or a mixture of both. Downsides to direct injection are cost and emissions.

Audi's direct-injection 3.2-liter V6. Click on image to enlarge.

Fuel pressures must be higher in a direct-injection engine because the fuel is being injected directly into the cylinder. Higher fuel pressures mean more-expensive fuel pumps and more-expensive fuel delivery hoses. Secondly, direct-injection engines can produce more NOx emissions. To combat this problem, a second catalytic converter might be necessary.

Isuzu offered a direct-injection engine on the 2004 Axiom, but that vehicle is no longer in production. Today, Audi, BMW, and Volkswagen offer direct injection on a few gas engines. According to Doug Clark, director of PR at Audi America, "the direct-injection 2.0- and 3.2-liter engines offered by Audi and VW offer more power, more torque, and greater fuel efficiency."

Because of increased manufacturing costs, direct-injection technology remains focused on luxury models where profit margins are higher. As volume increases, however, this power- and economy-increasing technology will find its way into less-expensive model