Dual power: 2006 Prius hybrid is no longer a compact

Friday, February 10, 2006

Toyota makes the best-selling hybrid on the planet, but they didn't make the first one. In the mid-50s I was driving around in my own hybrid of sorts. My plywood miniature car was powered by an old Briggs and Stratton 1-hp lawnmower engine, but to get it moving I had to push it, jump in, give it full throttle and engage the hand clutch. Away I'd go, to the envy of every boy in the neighborhood.

A hybrid is simply a combination of different forms of propulsion, and the technology is used in locomotives, marine vessels, even airplanes. The Prius combines a small gasoline engine with an electric motor and battery.

Redesigned in 2004, the Prius is larger, more fuel efficient and cleaner-running than the original, and now has an all-electric climate control system that keeps the passengers comfortable even when the gas engine is not running, as when sitting at a stop light. It is a midsize car, whereas the original Prius was a compact. The name comes from the Latin word for "before." With an attractive purchase price of a tad over $20,000 and a reputation as the most fuel-efficient sedan on the market, it has become the darling of Hollywood.

Prius' efficiency doesn't detract from passenger comfort or cargo capacity. It's a little smaller than other midsize sedans, but somehow tall passengers have adequate room even in the rear seats. Ample use of glass gives the cabin on open, airy feel. The use of quality interior materials creates an upscale image. Trunk space measures an impressive 16.1 cu. ft. and cabin volume is a spacious 96.2 cu. ft. (A Toyota Camry is only slightly larger, with 101.7 cubic feet. )

Driving the Prius is a unique experience. The moment I slid into the driver's seat I knew technology had taken me into new territory. Where I expected to see gauges and warning lights there were none. The main instrumentation is in the center of the dashboard, where a multi-function screen displays the "Hybrid Synergy Drive" power flow in action. The digital speed indicator is slightly to the right of the steering wheel where the windshield meets the dashboard.

You don't really "start" this car -- you "turn it on" by pushing a POWER button on the dashboard. With the "Smart Entry and Smart Start" option the driver has the key fob in a pocket or purse. When the driver touches the door handle a sensor receives a signal from a transponder in the fob and unlocks the door. The fob is inserted in a slot in the instrument panel and the POWER button is depressed. The central information panel wakes up as electrical energy surges from a 202-volt sealed nickel-metal-hydrid battery, and the climate control system comes alive. But the engine does not start. Even as you move the stubby gearshift control on the dashboard into Drive, the engine does not start. Even as you press the accelerator on the floor and move with the traffic, the engine does not start. You begin moving totally on electric power that is routed to a 67-hp AC motor capable of 295 lbs.-ft. of torque. Only when you reach about 30 mph does the gas engine come alive, assuming you keep a light foot on the accelerator.

Keeping the battery charged and providing additional power when needed is a 1.5-liter aluminum 4-cylinder engine producing 76-hp at an amazing 13-to-one compression ratio. It provides good acceleration when pulling in unison with the electric motor. Zero to sixty seconds arrive in about 11 seconds.

A generator (actually the electric motor working as a generator) recharges the battery when the vehicle is coasting, braking or the gas engine is spinning the generator. Coasting creates an excess of electricity, as does applying the brakes gently. Apply the brake pedal harder and normal braking occurs, creating heat and wasting energy, as in a typical car. But apply the brakes gently and the generator captures the energy and charges the battery -- a process called "regeneration".

Prius uses independent MacPherson struts with stabilizer bars front and rear, and torsion beam suspension at the rear. The ride is tuned to the plush side, in typical Toyota fashion. The ride is quiet and smooth, the transmission is of the constant velocity type, and the transition from electric to gas propulsion is seamless.

Toyota guarantees the battery for 8 years or 100,000 miles. That's in addition to the standard Toyota powertrain warranty of 5 years/60,000 miles and the basic three-year/36,000 mile warranty. There is a Federal tax incentive for purchasers of hybrids. There are more than 650 Prius hybrid patents. And to think I built one before Toyota got the idea!

Steve Robertson of Robertson's Creative Photography is a car enthusiast and former staff writer/photographer for the Southeast Missourian. Contact him at SteveR@cablerocket. com

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