TECH OVERVIEW OF THE 2005 IMPORTS

Motor,  Dec 2004  by Weissler, Paul

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Cylinder deactivation, direct fuel injection, broader hybrid applications, variable valve lift and timing and several other innovations are described in this year's import report.

The Year of the Car, it turns out, doesn't apply only to the 2005 domestic cars (see last month's tech report). Import nameplates have their own lists of new offerings, and although some of the technology on the various makes and models is similar, there also are major differences.

Subaru has new-generation Legacy sedans and Outback wagons with major new powertrain arid chassis designs to go with the new styling. Honda has a new Accord hybrid and Odyssey minivan, and its Acura line moves the RL further upscale. Volvo has introduced a new S40/V50 series, based on a Ford world platform also used by the Mazda 3, but with a Volvo powertrain and trademark safety features. Audi's new A6 hits its first directinjection gasoline V6 for the U.S. market. The Mercedes SLK may be a familiar nameplate, but the 2005 model has the company's first V6 with variable valve timing. It also gets the sevenspeed automatic transmission introduced last year on the E-Class.

And there's more, as you'll see. Here's what's coming out of the impoit camps for 2005.

Honda

Of immediate interest to independent shops is that the new Odyssey becomes the first high-volume vehicle to have Michelin FAX System (so-called runflat) tires, which have a run-flat structural insert and a special bead attachment. Other vehicles, such as the Dodge Viper, Corvette and Cadillac XLR, use a different technology, which adds stiffness to the sidewalk. According to Michelin, PAX tire punctures can be repaired with conventional patching and plugging, and the tires can be mounted and removed with many existing changers with a new adapter kit (available from Hunter, Corghi and Accu-turn at this time). Furthermore, Michelin has distributed to all Honda dealers and designated independent repair shops the Odyssey "hatboxes," which are plastic containers containing a complete assembly-tire and wheelready for inflation and mounting.

All 2005 Odysseys are equipped with a 255-hp, 3.5L V6, an engine with variable valve timing and variable lift. However, that engine in the Touring and EX versions also is Hondas first with cylinder deactivation. It runs on just three cylinders in deactivation mode, when the rear bank is disabled. This choice was made because the transverse engine's front bank can be cooled more effectively when its running solo. The method is unique to Honda, which builds on the variable valve lift system using a hydraulic circuit with a dual feed through a threeway solenoid-type spool valve.

Normal operation is all six cylinders with variable valve timing and variable intake valve lift, using Honda's three-rocker intake valve system with oilpressure-controlled pistons switching the valve operation from individual lift profiles to the rocker with greater lift at high rpm. With cylinder deactivation, the pistons switch the intake and exhaust valves to rockers with zero lift cam lobes. Because cylinder deactivation occurs at relatively low rpm (vs. high rpm for the increase in valve lift), it takes a new oil pumping system to provide the pressurized oil.

A three-cylinder engine could be noisy and rough at low rpm, so Honda took two innovative steps-front and reai" vibration-canceling, electronically controlled, fluid-filled engine mounts and active noise cancellation (ANC). The powertrain computer calculates engine vibration for the rpm and a solenoid-controlled metal diaphragm in each engine mount creates a countervibration against the fluid to cancel the engine vibration. Similar mounts have been used by Lexus and Honda to improve idle smoothness, but the Honda system is the first to work over a wide rpm range. ANC is an out-of-phase "noise" broadcast by the sound system to mask any engine booming noise that is not controlled completely by the engine mounts. The counteracting noise also is broadcast as the engine is started and is idling.

Does this lead into a change in a technicians thought processes for diagnosis of engine roughness? Obviously, because if it occurs at idle or in three-cylinder mode, it might not be caused by spark plugs, valves, etc., but by a malfunctioning engine mount or even a problem with the vehicle s sound system.

Cylinder deactivation is combined with a hybrid electric powertrain system on the Honda Accord hybrid, which uses a 3.0L version of the 240-hp V6. Honda does not produce a "true hybrid," because the Civic and now Accord versions (along with the original Insight) do not run on electricity alone. The Integrated Motor Assist provides an acceleration boost for the gasoline engine. But in the real world, our tests demonstrated that the fuel economy is there; the Civic hybrid electric got 45 mpg in mixed driving, mostly highway. The EPA ratings for the Accord V6 hybrid electric are 30 city/37 highway, which are more typical of four-cylinder engine numbers. This model also will be equipped with an electrically operated hydraulic power steering pump, eliminating the belt drive.