Lexus recently debuted the all-new 2013 GS350 at the Pebble Beach Concours d�Elegance, but waited until the Frankfurt auto show to reveal the new GS450h hybrid variant. As we found out driving a prototype of the new GS350, Lexus�s new GS platform is sportier than the last one, and the new hybrid version should be no different. But more central to the GS450h�s fuel-sipping mission, Lexus made several tweaks to its hybrid system to extract a significant efficiency boost over the outgoing car.
Speedy Hybrid
The original GS450h was quicker than its non-hybrid GS350 counterpart, but didn�t quite deliver when it came to the expected bump in fuel economy. This must have rubbed Lexus the wrong way, because this time around, the company is claiming a fuel-efficiency improvement of more than 30 percent versus the old car�with similar performance. Engineers took Lexus�s corporate 3.5-liter, port- and direct-injected V-6 engine, increased the compression ratio from 10.5:1 to 13.0:1, and adapted it to run on the Atkinson combustion cycle. In an engine running the Atkinson cycle, the intake valves stay open longer to reduce energy losses and convert combustion to engine power more effectively. For extra green points, Lexus is going after a Super-Ultra Low Emissions Vehicle II classification for the GS. The updated engine teams up with an electric motor and a generator, and sends power to the 450h�s rear wheels through a continuously variable transmission, same the previous generation.
The electric side of the new GS450h�s propulsion equation also received some attention. The 2013 450h features an upgraded power control unit that limits the voltage sent to the drive motor when the driver selects Eco mode and boosts it when one of the two Sport modes is engaged. Drivers tailor their drive by choosing from among Eco, EV, Sport S, and Sport S+ modes. Lexus reduced the electric motor�s friction, and the generator was made more effective by expanding the regenerative-braking operating window.
Despite the improvements to the GS450h�s engine and electronics, the 2013 model produces a combined 338 hp�2 fewer than before. Nevertheless, Lexus thinks the GS450h will be able to run from 0-to-60 mph in 5.6 seconds. The last GS450h we tested made it to 60 mph in 5.5 seconds, so that�s probably a good guess. Finally, the hybrid�s rear-mounted nickel-metal hydride battery pack was repackaged to reduce trunk intrusion.
Handsome Hybrid
Lexus gave us a peek at the 2013 GS450h earlier this month, and just as we suspected, the hybrid looks pretty much the same as the GS350. This means the 450h has the same chunky road stance and techno-style of the gas-only GS. The key differentiators between the GS350 and 450h are the hybrid�s bug-like tri-lamp headlights, which are laced with the standard car�s LED array, hidden exhaust outlets, and blue-tinged Lexus badges front and rear. Like the exterior, the hybrid GS�s interior is almost exactly the same as what you�d find in a GS350 except for a more-efficient climate-control system Lexus has dubbed �S-Flow,� a bamboo-trimmed steering wheel, and Lexus�s hybrid monitor that displays the system�s happenings to the driver.
Based as it is on the 2013 GS350, the new 450h should be a more engaging drive than the old one. The GS hybrid rides on the same more-rigid platform as the new 350 and features its revised control-arm front and multilink-rear suspension, In addition, Lexus will offer its Dynamic Handling system for those who want a bit more sportiness. Dynamic Handling integrates Lexus�s variable suspension, rear steering, and variable-ratio steering. Standard 17-inch and optional 18-inch wheels not only should help the plethora of available electronics keep the GS450h going where you point it, but also look good. We�re curious to see if the new 450h is a dynamic match for the similarly powerful Infiniti M35h hybrid, but we�ll just have to wait until the new GS450h hits dealerships sometime in 2012. View Photo Gallery
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2013 Lexus GS450h Hybrid car new and review photo and info
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