It's not yet in dealerships, but the 2013 Lexus GS 450h offers a big boost in gas mileage for buyers of mid-size sport sedans.

The all-new GS 450h hybrid is expected to be rated at 29 mpg city, 34 mpg highway, for a combined rating of 31 mpg.

In comparison, the 2012 Infiniti M35h hybrid sport sedan, also a mid-size entry, is rated at 27 mpg, 32 mpg highway, and 29 mpg combined. Infiniti has promoted the hybrid M sedan as the sole car offering both 350 horsepower and a highway rating above 30 mpg.

The new Lexus GS hybrid model doesn't quite hit that mark, with a total combined power of 338 hp to the rear wheels from its 286-hp 3.5-liter V-6 engine and pair of motor-generators, which have maximum peak outputs of 134 kilowatts (180 hp) and 147 kW (200 hp) respectively.

Unlike the Infiniti's lithium-ion battery pack, the new 2013 Lexus GS 450h continues with Toyota's traditional nickel-metal-hydride chemistry. Those cells are heavier and bulkier for a given energy content, but they're well-proven in more than 3 million hybrids from Toyota and Lexus since 1997.

2013 Lexus GS 450h

2013 Lexus GS 450h

Among other features of the all-new luxury hybrid sport sedan are LED headlamps and the Lexus Dynamic Handling System, essentially a variation on four-wheel steering to keep the car more stable as it corners.

Down the road, Lexus may launch a plug-in hybrid version of the GS sedan, according to an interview with GS chief engineer Yoshihiko Kanamori. That car is most likely targeted at European cities with zero-emission city centers, but it may well arrive in the U.S. as well further down the road.

The 2013 Lexus GS 450h made its world debut at the Frankfurt Motor Show in September. It will arrive at Lexus dealers in the U.S. early next year.


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