Technologue 2002: An engineer's guide to the auto show

Automotive Industries, Dec, 2001 by Don Sherman

You are the engineer's engineer -- an avowed authority in your field of expertise. You know everything there is to know about Ravigneaux gear sets, insulated-gate bipolar transistors, or closed-loop stability control. But you probably don't have a clue what your counterparts down the hall or at a venture-partner's facility across the globe are doing. An occupational hazard in this business is that you seldom see how your critical chunks of the puzzle fit the big picture.

All the pieces comprising that picture are available at Detroit's North American International Auto Show (NAIAS). The only problem is the shiny fenders and sequined hostesses seem more like a kaleidoscope than the telescope on the auto industry you really need. That's where we come in. Consider AI's preview of coming technological attractions to be your tool for twisting the NAIAS kaleidoscope into focus. A few minutes boning up on emerging trends here will arm you with all the perspective you'll need to separate this year's frivolous concept-car feature from next year's indispensable product attribute.

Powertrain

If you've written off pistons and pushrods as obsolete 20th-century artifacts, you're ahead of the game. While it's true that the quest for zero emissions and higher efficiency is driving global transportation toward a hydrogen-based fuel-cell future, the broad-scale implementation of these space-age technologies won't occur for at least a decade. Honda and Toyota are racing feverishly to field the first demonstration vehicles (due sometime in 2003), but there are monumental infrastructure, engineering and cost problems to solve. In the meantime, automakers will boost efficiency while maintaining or improving performance with a creative blend of new and old -- the best internal-combustion engines ever to roam the planet teamed up with battery-powered electric motors.

Hybrid-electrics are meaningful stepping stones on the path toward a pure-electric fuel-cell future. Combining the attributes of two complimentary energy converters yields significant mileage and emissions gains, particularly in urban driving. The current poster child for hybrids is the 2002 Honda Civic, a second-generation production model on the heels of the interesting but impractical (and unprofitable) Insight. Now that there are two 50-mpg family sedans -- the Civic, plus Toyota's Prius -- hybrid momentum will build, setting the stage for the first gas-and-electric-powered trucks due from domestic makers in 2004.

Expectations are that hybrid technology will boost their mileage at least 15 percent with no loss of performance. A recent J.D. Power study forecasts half-a-million hybrid sales by mid-decade.

In spite of the electric ground swell, never in the history of Nicolaus Otto's age-old invention has there been such a burst of interest and innovation in piston engines. Thanks in part to the advent of electronic controls, engineers are trimming losses, perfecting combustion, boosting volumetric efficiency and raising redlines. With one-stop shopping, you can find several of the most advanced engine features under the hood of BMW's new 745i flagship. Variable valve timing (VVT) on both the intake and exhaust tracts benefits idle smoothness, speeds catalyst warm-up and enhances high-rpm breathing. A separate mechanism alters intake-valve lift through a wide range to eliminate the throttle plate and associated pumping losses. Eight rotating drums inside the Bimmer's intake manifold continuously optimize the length of induction passages to maximize torque throughout the rev range. The bottom line is a 14-percent gain in output and fuel efficiency over the 4.4L V-8 still powering other BMW models.

VVT is quickly becoming standard practice. General Motors Corp.'s twist on that concept is an experimental V-8 with two cams in the block instead of the heads. By separating the lobes that open the intake valves from those that operate the exhaust valves, GM will be able to combine the power, smoothness and emissions advantages of VVT with the cost and packaging benefits inherent to pushrod-type valvetrains.

Shutting down cylinders when they're not needed is an old idea that Mercedes-Benz revived for its thirsty V-12 engines. GM calls the approach "displacement on demand" and will use it extensively to help its truck V-8s emulate V-6s at the gas pumps. Honda's new Civic drops three of its four cylinders off-line during deceleration to reduce engine braking, thereby enhancing that hybrid's regenerative-braking capability. Another standard hybrid trick is to simply switch off the IC engine at stoplights.

Transmissions are also enjoying a glorious day in the sun. Continuously variable (CVT) designs have finally moved out of the curiosity category and into the mainstream. Audi scored a major technological breakthrough by switching the drive chain from compression to tension, thereby almost doubling the torque capacity of its Multitronic transmission (available in both A4 and A6 lines) compared with previous CVTs. Step-change automatic transmission engineers have responded to this turf challenge with initiatives of their own. Both ZF and Aisin have developed 6-speed automatics with broad ratio spreads. The first production applications for the ZF unit are at BMW (7-Series) and Jaguar (S-Type). Aisin's design is for future front-wheel-drive models. Another notable transmission development is the addition of servomotors to manual gearboxes to automate clutching and shifting. This concept trickled down from Formula One racing to Ferrari's road models and is spreading through the exotic ranks (Aston Martin, Maserati ) on its way down market.