Honda has rolled out its re-engineered third-generation Odyssey minivan for 2005. Aside from increasing interior comfort, flexibility and safety features, Honda provided a new Odyssey gasoline powertrain that increases performance and fuel economy while lowering emissions. But for all the great improvements in technology, the fuel economy and emissions fall far short of the potential of an expected hybrid gasoline-electric version.

The new Odyssey engine is a 3.5-liter 24-valve V-6 aluminum-block-and-head design that is both lightweight and powerful. Two engine configurations are available: the standard 255 horsepower VTEC V-6 and a 255 horsepower i-VTEC V-6 with Variable Cylinder Management(VCM).

VTEC (Variable valve Timing and lift Electronic Control) optimizes the flow of fuel/air mixture for high RPM operation while maintaining smooth and economical low RPM operation—it’s another way of getting more from an engine without increasing its size and hence fuel consumption. (Honda was an early innovator in this technology, introducing the first VTEC system in 1988.)

Variable Cylinder Management increases fuel efficiency by shutting off three of the engine’s six cylinders during cruising and deceleration. For performance, the engine operates on all six cylinders during acceleration and heavy load situations. The system works seamlessly and is transparent to the driver in feel and sound.

The resulting new powertrain delivers a 15 horsepower (6%) boost compared to the 2004 model and an increase in EPA highway fuel economy by as much as 12% on models with the i-VTEC VCM engine. The i-VTEC VCM models yield 20/28 mpg city/highway.

To ensure quiet operation, Honda equipped the VCM models with Active Noise Control (ANC) technology that works with the audio system to cancel inherent noise produced by the VCM system (along with some road noise). Additional dampening occurs through the use of an Active Control Engine Mount System (ACM) that uses electrically activated dampers to minimize engine vibration.

In addition to providing class-leading fuel economy, the 2005 Odyssey qualifies as a LEV2-ULEV (Ultra Low Emissions Vehicle in California and some Eastern states) and Tier 2 Bin 5 in the Federal emissions program. To achieve Tier 2-Bin 5 classification, a vehicle must reduce NO_x emissions by at least 75 percent over pre-existing levels.

In comparing the 2005 Odyssey to its gasoline-engine competition, it is evident that Honda has moved ahead—but that the competition is not that far off.

It’s interesting to note that although the 2005 Odyssey is the heaviest of the models compared, it also offers the best fuel economy, due to the improvements in the engine. This is a fairly consistent reflection of what happens in the current marketplace, where engine and technology enhancements are offset by increases in size, weight and power-draining accessories.