The third generation of a highly successful Mercedes-Benz that began the industry trend toward SUVs with a more car-like ride, the dramatically styled M-Class is instantly recognizable as a sport utility vehicle. With its large wheel openings and 'two-box' profile of its nose and cabin, this eye-catching interpretation of a modern SUV makes a strong presence that projects trend- setting design and quality. The M-Class line for 2013 is comprised of four models, all with direct injection – the thrifty ML350 BlueTEC diesel (240 horsepower, 455 lb.-ft. of torque), the popular ML350 with its V6 gasoline engine (302 hp, 273 lb.-ft.), the biturbo V8- powered ML550 (402 hp, 443 lb.-ft.) and the high-performance ML63 AMG (518 hp, 516 lb.-ft., and 550 hp, 560 lb.-ft. with the AMG Performance Package).
Four M-Class Models
All four models come with proven Mercedes-Benz 4MATIC all-wheel drive (the ML350 is also available with rear-wheel drive). As modern all-wheel-drive systems become more refined, they are becoming more popular, especially in the luxury car market. With negligible weight and fuel-efficiency tradeoffs, full-time four-wheel drive provides year-round traction and stability benefits on both wet and dry roads. Fuel efficiency has been optimized, due to a number of innovative measures that minimize the energy needed to turn the extra gears and shafts.
4MATIC Four-Wheel Drive Sets a Trend
The M-Class line is equipped with a transmission that provides even better fuel mileage, more responsive driving, quieter operation and increased durability. The latest transmission features a more advanced torque converter lock-up clutch and is designed to work best with a new type of low-viscosity ATF transmission fluid, colored blue instead of the usual red.
With 302 horsepower and 273 lb.-ft. of torque, the 3.5-liter V6 gasoline engine is assembled in a new block with 60-degree cylinder angles, so it doesn't need a balance shaft for smooth operation. The engine features aluminum cylinder heads, pistons and cylinder block (with cast-in Silitec cylinders), as well as a crankshaft, connecting roads and valves made of special forged steel.
302-Horsepower V6 Engine for the ML350
Based on its highly successful 5.5-liter predecessor, the 4.6-liter V8 engine has 20 percent smaller displacement but generates more power than the previous engine – 402 horsepower and 443 lb.-ft. of torque. Its smaller displacement is more than offset by the power boost of its twin turbochargers – one for each bank of cylinders. Piston crowns are thicker to handle the higher combustion pressures, while shorter connecting rods allow existing block dimensions to be retained.
402-Horsepower V8 for the ML550
AMG uses its own 5.5-liter version of the 4.6-liter Mercedes-Benz biturbo V8 that also produces more power and better fuel economy simultaneously. Replacing AMG's normally aspirated 6.3-liter V8, the smaller engine features twin turbochargers, direct fuel injection, and multi-spark ignition. Compared to the 4.6-liter biturbo, the ML63 AMG powerplant makes use of more displacement (a larger cylinder bore and longer crankshaft stroke), higher turbocharger boost, and slightly lower compression. Identified inside the company as the M157, the AMG twin-turbo V8 produces 518 horsepower and 516 lb.-ft. of torque. With the optional AMG Performance Package, these figures increase to 550 hp and 560 lb.-ft.
518-Horsepower V8 for the ML63 AMG
All three gasoline engines (ML350, ML550 and ML63 AMG) make use of industry-leading electronics technology first used on Mercedes-Benz diesels – electronic fuel injectors that spray gasoline directly into the combustion chambers rather than indirect port fuel injection most gasoline engines used in the past. Featuring a piezo-ceramic crystalline element that changes shape instantly when electrical current is applied, blazingly fast piezo injectors make it possible to design very sensitive and precise injection systems, including the ability to program several small injections with each piston stroke. The first injection is sprayed into the combustion chamber as the piston is descending on the intake stroke. Depending on speed, load and temperature conditions, another injection or two takes place during the compression up- stroke before ignition, forming a stratified mixture. A fourth injection can stabilize combustion if it's needed.
Direct Fuel Injection
Working together with direct injection, a rapid multi-spark ignition system begins combustion with the first spark, but has the capability to recharge and deliver up to three more sparks within a single millisecond, creating a gas plasma with more expansion than conventional ignition. The time lapse between sparks is adjustable, so combustion duration can actually be controlled, resulting in two percent better fuel economy, and a total of four percent improvement in combination with direct fuel injection.
Multi-Spark Works with Multi-Squirt
Mounted on the ends of the intake and exhaust camshafts, the hydraulic camshaft adjusters that vary valve timing are 35 percent faster than in the past, and with a wider range of 40 crankshaft degrees. Despite their improved performance, they're also more than a half inch smaller in height and width. Smaller valve timing adjusters are made possible by a new cam chain drive system, in which the crankshaft drives an intermediate shaft above the crank. In turn, the intermediate shaft drives two short chains – one for each cylinder bank – that loop around the intake and exhaust camshaft drive sprockets. The latest chain drive results in less tension and lower chain dynamics, for even lower friction and less noise. A fourth chain drives a variable vane-type oil pump in the bottom of the engine. At low engine speed and load, the oil pump only generates about 28 psi (or two bar) of oil pressure, and nozzles that spray cooling oil on the pistons are off. As engine speed and load increases, oil pressure goes up, and the oil spray nozzles are turned on. In this way, less energy is used when less cooling and lubrication is needed.
Refined Cam Chain Drive
Even the cooling system is significantly refined in the direct-injection engine, beginning with a two-stage flow circuit through the cylinder head. This improved coolant flow results in better heat dissipation, despite lower coolant pressure, so that the water pump uses less engine power. A three-phase cooling system helps the engine warm up very quickly. When the engine is first started, no coolant circulates. Then, as the engine warms up, coolant begins to circulate within the engine, but not through the radiator. Only when the coolant temperature reaches 221 degrees Farenheit (or 189 degrees F. under high load), coolant also circulates through the radiator. Coolant circulation through the heating system for the car's interior is controlled separately.
Three-Phase, Low-Load Cooling System
With 30 percent better fuel economy than a comparable gasoline engine, the ML350 BlueTEC is powered by a purpose-built 3.0-liter V6 diesel producing 240 horsepower and an astonishing 455 lb.-ft. of torque. The ML350 BlueTEC begins with a four-valve-per-cylinder diesel featuring centrally located piezo- electric injectors, CDI direct injection, a variable-nozzle turbocharger and exhaust gas recirculation. Building on this foundation of advanced engine design, the ML350 BlueTEC incorporates several modular after-treatment units in the exhaust stream – an oxidizing catalytic converter, a maintenance-free particulate filter, an SCR converter and an NOx storage converter. In the 'denox' storage converter, nitrogen oxides are absorbed temporarily, and during brief regeneration pulses of a richer fuel-air mixture, the nitrogen oxides are released, reacting with other exhaust gas to form harmless nitrogen. These regeneration pulses also raise temperatures in the particulate filter, which automatically burns off the deposits.
BlueTEC – A Blueprint For The World's Cleanest Diesels
Among the many standard life-saving features on the M-Class is the innovative ATTENTION ASSIST system that can alert the driver to the first signs of drowsiness, a factor that causes more than 100,000 accidents a year in the U.S. A steering sensor is coupled to smart software that uses 70 parameters to establish a unique driver profile during the first 20 minutes of driving. Between 50 and 112 mph, the system identifies the erratic steering corrections drivers make as they begin to get drowsy and triggers an audible warning, and a 'Time for a Rest?' message with a coffee cup icon appears in the instrument cluster.
ATTENTION ASSIST Cautions 'Time For A Rest?'
Other examples of trailblazing M-Class innovations include: Lane Keeping Assist, which alerts the driver by simulating rumble strip vibration in the steering wheel if the car drifts from its lane without the turn signals on. It operates at speeds above 37 mph via a system that recognizes lane markings, thanks to a small camera in the windshield and a computer that analyzes the video images. Blind Spot Assist monitors both blind spots behind and to the side of the vehicle. Whenever a turn signal is activated with a vehicle in the blind spot, the driver gets visual and audible warnings. A separate option, Active Lane Keeping Assist and Active Blind Spot Assist incorporate an intervention feature, in which ESP braking automatically helps correct the car's course if the driver doesn't heed the initial warning. Adaptive Highbeam Assist uses a small video camera to sense both headlights and taillights, then softly and automatically transitions between high and low beam operation to avoid dazzling other drivers. With this system, the range of the headlights can be varied infinitely from their current 220 feet to up to 1,000 feet.
More Safety Systems Assist the Driver
The M-Class comes with an electrically-assisted rack-and-pinion steering unit. Not only does the new electric steering provide built-in speed-dependent power assist, but it also offers fuel savings. The engine no longer has to turn a hydraulic power steering pump, and the new steering only uses electrical power when the wheel is being turned. The electric steering also makes other innovative systems possible, such the optional Active Parking Assist, which makes parallel parking a stress-free cinch. Below about 20 mph, a 'P' icon appears in the dash to show that an electronic parking space search is active. Whenever an adequate-size parking space is found, an arrow appears next to the 'P' icon. When reverse is engaged and the driver confirms Advance Parking Assist is desired, the system initiates automatic steering as the driver controls acceleration and braking at speeds below 7 mph. The system allows two forward corrections, after which the wheels are straightened.
Electric Rack-And-Pinion Steering
PRE-SAFE® is a revolutionary safety system that can actually sense an impending collision before it happens and take measures to protect occupants during those valuable seconds before impact. The PRE-SAFE system tightens the front seat belts before a possible impact. Whenever the PRE-SAFE system is triggered, the side windows also close to provide better support for the window curtain air bags. If the system senses an impending rollover, the sunroof also closes.
PRE-SAFE® Gives M-Class Reflexes to Protect Occupants
Along with the GL-Class, the M-Class sport utility vehicle is produced at the Mercedes-Benz plant in Tuscaloosa, Alabama. The Tuscaloosa plant began production in 1997 with the first generation M-Class. In 2011, the plant produced more than 148,000 vehicles and employed more than 2,800. Starting in 2014, the Tuscaloosa plant also will produce the successor generation of the current C-Class for the North American market. By 2015, Daimler AG will have invested more than $4.4 billion into the facility.
The Mercedes-Benz Alabama Plant
Mercedes-Benz USA (MBUSA), headquartered in Montvale, New Jersey, is responsible for the distribution, marketing and customer service for all Mercedes-Benz products in the United States. MBUSA offers drivers the most diverse line-up in the luxury segment with 13 model lines ranging from the sporty CLA-Class four-door coupe to the flagship S-Class and the SLS AMG GT. MBUSA is also responsible for the distribution, marketing and customer service of Mercedes-Benz Sprinter Vans, and smart products in the U.S. More information on MBUSA and its products can be found at www.mbusa.com, www.mbsprinterusa.com and www.smartusa.com.
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