USA: Cylinder deactivation, hybrid and new diesel technology make new 'best engines' list

By just-auto.com editorial team | 22 December 2004

Many of Ward's 10 best engines for 2005 highlight sophisticated new technology that not only improves mileage but also pumps up power.

The 10 are (engine and tested vehicle):

Audi AG FSI 3.2L DOHC V6 (Audi A6)
Audi AG 4.2L DOHC V8 (Audi S4)
DaimlerChrysler AG 5.7L Hemi Magnum OHV V8 (Chrysler 300C)
DaimlerChrysler AG Mercedes-Benz 3.2L DOHC I6 CDI Turbodiesel (Mercedes E320 CDI)
Ford Motor Co. 4.6L SOHC V8 (Ford Mustang GT)
General Motors Corp. Vortec 4.2L DOHC I6 (Chevrolet TrailBlazer)
Honda Motor Co. Ltd. 3L SOHC V6 IMA Hybrid (Honda Accord Hybrid)
Honda Motor Co. Ltd. Acura 3.5L SOHC V6 (Acura RL)
Mazda Motor Corp. 1.3L Renesis rotary (Mazda RX-8)
Nissan Motor Co. Ltd. 3.5L DOHC V6 (Infiniti G35 Coupe)

Cylinder deactivation, petrol-electric hybrids and advanced diesel technology all are represented by winners on this year's list.

Another important emerging technology that generates more power while also improving fuel economy, direct gasoline injection, gave Audi AG a win for its first North American application of its all-new "FSI" 3.2 litre DOHC V6. The 255-horsepower motor produces 35 more horsepower than the engine it replaces, yet delivers as much as 10% better fuel economy. Audi's direct- injection powerhouse also operates on the US regular-grade (87-octane) unleaded petrol.

Cylinder deactivation, which allows an engine to operate with half its usual number of cylinders when full power is not necessary, is another critical new fuel-saving technology featured on two best engines winners for 2005. Chrysler's now-famous 5.7 litre "Hemi" V8 incorporates the company's multi-displacement system to instantaneously shut down four cylinders when not needed.  Meanwhile, when power is required, MDS immediately reactivates the cylinders to generate the engine's full 340 horsepower.

Honda Motor also uses its own cylinder-deactivation system - Variable Cylinder Management - to boost fuel economy for the new 3 litre SOHC V6 used in the Accord Hybrid. The car also has Integrated Motor Assist hybrid-electric technology to boost power and increase fuel efficiency. While the Accord Hybrid is 15 horsepower stronger than its conventional counterpart, VCM and IMA combine to improve fuel efficiency by a startling 38% in the city and 23% on the highway.

Mercedes-Benz unit wins an award in the first year of availability of its new CDI 3.2L inline six-cylinder turbodiesel. As with Audi's FSI, the Mercedes diesel employs high-tech direct fuel injection and a host of other sophisticated electronic controls to create a diesel engine that generates spectacular torque and almost 40% better fuel economy than a similar-size petrol six-cylinder engine.

"Suddenly, there is a confluence of new engine technology that engineers can deploy to meaningfully increase fuel economy while not sacrificing -- and sometimes even improving -- power output," said Ward's senior technical editor Bill Visnic. "The speed with which these sophisticated new systems have come to market, for comparatively affordable engines, is stunning.

"Power and economy no longer are mutually exclusive development goals," he added. "Engine engineers are liberating genuinely remarkable new levels of performance."