2006 Honda Civic Hybrid vs. 2006 Toyota Prius

There are three technical explanations for this splendid showing: the motor's greater power (up 54 percent), the engine's new three-mode VTEC valvetrain, and the car's smarter means of recapturing energy while braking (a 170 percent efficiency gain, claims Honda). The previous IMA Civic's VTEC offered two induction modes: normal or with three of its four cylinders deactivated. The 2006's three-stage i-VTEC adds to the normal mode, both a higher-performance induction setting and, when the occasion arises, deactivation of all four cylinders. The last situation mostly occurs while decelerating, whereupon all the valves close as the pistons just spring off their cylinders' repeatedly compressed air. While not as efficient as Toyota's complete halting of the crankshaft, it's considerably better than becoming a purposeless air pump. It's also a condition that allows the Civic to be propelled by its electric motor alone--that is, when the speed is low enough, the batteries replenished enough, and several planets are in alignment. Under these rather limited circumstances, at least, it can kinda, sorta claim to be a full hybrid just like Toyota's Hybrid Synergy Drive (HSD).

Which brings us to the Prius's magical powertrain. Don't feel badly if you don't get it. Shortly after the first-generation Prius was introduced to the U.S. market, the government asked Argonne National Laboratory to dissect the thing, and from reading its report, even the big foreheads in New Mexico were wrinkled.

2006 Honda Civic Hybrid Engine

Think of it as an open differential, but working in reverse--that is, the driveshaft is now the output. Into one axle goes the engine's power while the electric motor's contributes directly to the driveshaft. How about the other axle? It's fed by a second, small electric motor that sometimes acts as the engine's starter, sometimes as a generator, plus offering up whatever forces are needed to make the planetary gearset do double duty as a CVT. Conducting this rabble is software of Toscaninian virtuosity.

2006 Toyota Prius Engine

In operation, the Civic and Prius offer distinct high-mileage experiences. Whereas the Prius frequently whispers around at low speeds in George Jetson golf-cart mode--undetectably lighting off its engine whenever load demands--the Civic's auto-start is apparent but quick (the engine's running before your right foot gets from the brake to the throttle). More relevant is the Civic's comparative slowness.