January 13, 2009 In keeping with the strong theme of efficiency over gas-guzzling muscle at this year's Detroit NAIAS auto show, Lexus has introduced a new hybrid sedan to its lineup, slated to go on sale in Q3 2009. 30% more fuel-efficient than anything else in the Lexus range, the 187-horsepower, 4-cylinder HS 250h is an acknowledgement by the biggest-selling luxury car brand in the USA that even the cashed-up luxury market wants to control its use of fossil fuels. While the HS 250h is miserly on fuel (Lexus claim it will drink less per mile than the tiny Smart Fortwo) it's still a big spender on the interior, with some serious driver assist features, heads-up display, radar-governed cruise control, parking cameras and a voice-controlled nav/premium audio system.

Lexus are billing the HS 250h "the world's first dedicated luxury hybrid" - which sounds a lot more impressive than it is. The company has been offering hybrids since 2005, this is just the first one built from the ground up to take advantage of the dual powertrain's efficiency potential. Still, the results are impressive.

The engine is completely new - Lexus' first four cylinder donk is a highly efficient Atkinson-cycle engine with 2.4-litre displacement and VVT-i (Variable Valve Timing with intelligence) that allows the expansion/power stroke to be longer than the compression stroke to extract the maximum possible power from each combustion. The engine, in combination with the hybrid electric drive system, makes a reasonably healthy 187 horsepower.

Other fuel-saving considerations include an exhaust heat recovery system that allows the engine to stop more often and for longer without losing optimal temperature, infra-red blocking windshields to help cool the interior without aircon, and a slippery aerodynamic profile that reduces drag as well as wind noise. Put together, Lexus claim the HS 250h will return better fuel economy than the miniature Smart Fortwo, which makes 33mpg around town and 41mpg on the highway cycle.

Emissions control has played a significant part in the interior design, with the extensive use of plant based "bio-plastics," also known as ecological plastics, throughout the cabin. This material's carbon-neutral classification reduces the total carbon emissions of the vehicle by a whopping 20% over its expected lifespan.

In terms of driver assist, Lexus has incorporated a new lane keep assist system that takes advanage of the electrically driven power steering system to help keep the car in the centre of the lane. When the lane-marker cameras detect that the car might be drifting out of its lane, an audible warning is delivered to the driver, as well as tactile feedback through the steering wheel to 'encourage corrective action.' There's also stability control, and an optional pre-collision system with dynamic radar cruise control.

In the event of a crash, a whopping ten airbags and active front headrests will cushion the blow, while the Safety Connect system automatically informs the authorities. The system also allows the driver to call for emergency or roadside assistance, as well as phoning home its location in the event that the car is stolen.

The console and entertainment unit has plenty of goodies; Bluetooth phone connectivity, satellite radio, iPod connectivity, steering wheel controls, a retractable and well-positioned navigation screen, casual speech voice recognition, traffic weather, sports and stock information. Lexus Enform's Destination Assist feature lets drivers look up a range of businesses and points of interest and find them through the nav system. You can also plot up to 200 destinations on your PC, and send them to the car's computer for on-road use.

A late-summer (US) 2009 release date has been scheduled, but no pricing details are available as yet.

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