Mercedes-Benz ML450 HYBRID SUV

13 November, 2009 03:07:00

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Mercedes-Benz announced today that on Nov. 16 it will launch the ML450 HYBRID SUV, first European full hybrid vehicle to be offered in the US.

The ML450 HYBRID joins Mercedes-Benz’s existing lineup of fuel-efficient and environmentally compatible vehicles that includes the S400 HYBRID and the BlueTEC diesel models.

The new ML450 HYBRID will be offered as part of a special lease only option (no purchase) for a monthly lease price of $659 per month for 36 months and $549 per month for 60 months.

Featuring V8-like power with four-cylinder fuel economy, the ML450 HYBRID comes with two electric motors and a 275-hp V6 gasoline engine that work together to provide impressive hybrid power with fuel economy estimated at 21 miles per gallon around town and 24 mpg on the highway.

The new Mercedes-Benz ML450 HYBRID uses a 3.5-liter V6 gasoline engine, two magneto-electric motors and sophisticated hybrid electronics to produce more than 46 percent better fuel economy than a comparable V8-powered ML550 model.

Integrated within the modified automatic transmission, each electric motor serves a specific purpose. Dedicated to pulling away under electric power, the motor on the transmission output shaft generates 80 hp and 192 lb.-ft of torque. Located closer to the gasoline engine, the other electric motor is set up specifically for acceleration and is rated at 83 hp and 173 lb.-ft of torque. Working with both electric motors when full power is needed, the gasoline engine develops 275 hp and 258 lb.-ft. of torque.

The electric motors are powered by a liquid-cooled, 288-volt nickel-metal-hydride battery that’s hidden under the rear cargo floor. A powerful computer controls the hybrid system, recalculating the best operating mode 160 times a second. Capable of up to 50 million calculations per second, the system works to maintain an ideal balance between fuel economy and performance.

During parking and low-speed operation, the ML450 HYBRID runs on the electric drive only. On hard acceleration, the gasoline engine is started automatically, and it works seamlessly with the two electric motors for surprisingly good performance. The hybrid system includes a convenient start-stop function that turns off the gasoline engine – for example, when coasting up to a red light – and re-starts it during acceleration. When the ML450 HYBRID is at a traffic light, for example, the gasoline engine is off, but the AC compressor and steering pump are operated electrically, so air conditioning and power steering are fully operational.

During braking, the electric motor acts as a generator, slowing the SUV and recovering kinetic energy. Under heavy braking, the vehicle’s conventional brakes also come into play. Recovered energy is stored in the battery and re-used whenever the car runs only on the electric motors.

Mercedes-Benz engineers optimized the 3.5-liter V6 engine for good fuel economy by taking advantage of the Atkinson principle. By delaying the closing of each intake valve, the intake stroke effectively becomes longer than the compression stroke, increasing thermal efficiency, which reduces fuel consumption and exhaust emissions.

Although Atkinson engines inherently produce less low-speed torque and throttle response, they are ideal for hybrid vehicles because the electric motors compensate for this disadvantage by working with the V6 to provide excellent throttle response on acceleration. The Atkinson-cycle V6 engine has different cylinder heads, pistons and camshafts as well as modified variable valve timing control and a low-load oil pump for good fuel economy.

The ML450 HYBRID fulfills the same crash test requirements and offers outstanding active safety with stability control systems such as ESP, ABS and BAS, as well as 4MATIC all-wheel drive. The integration of the hybrid technology has been engineered to require no additional packaging space that would compromise comfort or functionality. The space available in the passenger cabin is as generous as before and the trunk capacity remains fully intact. From the outside, the ML450 HYBRID is recognizable by its modified hood, the BlueEFFICIENCY logo on the fender and by the HYBRID badge on its tailgate.

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