Hybrid Car Review

Toyota released the Lexus LS 600h and 600h L today in Japan. The new luxury hybrid will show up in the North America, Europe and other markets starting in June. (The L stands for Long and the h is for hybrid.) Set to sell for over $100,000, this vehicle is not for the light of pocket.

The LS 600h is a full hybrid, capable of operating in electric-only mode for short distances at low speeds. The 5.0-liter V8 gasoline engine is mated to two powerful electric motors and a 288-volt DC Nickel Metal Hydride (Ni-MH) compact battery pack installed behind the rear seat that is lighter and extremely quiet. Lexus engineers claim the V8 is equivalent to a conventional 12 cylinder in power.

At the same time, the fuel economy is set to what a luxury six cylinder is capable of. The preliminary EPA ratings set the LS 600h L at 20 mpg city, 22 mpg highway, 21 mpg combined.

LS hybrid is expected to receive a Super Ultra Low Emission Vehicle (SULEV) rating. A SULEV rating means it will be nearly 70 percent cleaner smog forming emissions than vehicles with a conventional internal combustion engine.

Since the gas engine can and will shut down when the vehicle comes to a stop, the power-steering system and air-conditioning compressor are electrically powered to reduce parasitic losses to the engine. The trunk also contains a 12-volt auxiliary battery that powers the audio, navigation, and other systems. A regenerative braking system further boosts fuel efficiency by recapturing energy normally lost in braking.

The performance of the AWD system is accomplished through a new transfer case that is ultra quiet, compact and equipped with a unique Torsen® limited-slip differential (LSD) that is 30 percent lighter in size and weight than previous Torsen® systems. To maximize the AWD system's performance, the LSD features a rear biased torque distribution of 40:60 under normal straight-line driving. The LSD automatically and continually adjusts power distribution between the front and rear wheels according to changing speed and road conditions.

The LS hybrid engine delivers a combined 438 horsepower with a dual-stage electronically controlled continuously variable transmission. The luxury hybrid is capable of accelerating from zero-to-60 mph in just 5.5 seconds. Even more impressive, the electric motor assists the gas engine in passing maneuvers. The LS 600h L rapidly accelerates from 50-70 mph in a rapid 3.5 seconds.

The new V8 is tuned to reduce vibration and sound by adding additional sound insulating materials around the cylinder head covers. Additional NVH reduction is achieved by reducing damper pulley tensions and perfecting engine mount sizes and locations through repeated testing by Lexus engineers.