More Power, Efficiency and Traction for the Mercedes-Benz CLS
The eye-catching Mercedes-Benz CLS63 AMG coupe has been fitted with 4MATIC all-wheel drive for the 2014 model year, and its 5.5-liter V8 is now rated at 550 hp and 531 lb.-ft of torque. A new higher-performance version of the CLS63 AMG called the S-Model, also with 4MATIC, produces an astonishing 577 hp and 590 lb.-ft. of torque. Rounding out the CLS line is the 4.6-liter CLS550 4MATIC, with 402 horsepower and 443 lb-ft. of torque. All three CLS models are powered by biturbo, direct-injection V8 engines.
The Benefits of 4MATIC All-Wheel Drive
AMG, the high-performance division of Mercedes-Benz, is fitting an increasing number of its models with 4MATIC full-time all-wheel drive. In addition to the CLS63 AMG and the popular AMG sport utility models – ML63 AMG, G63 AMG and GL63 AMG – the E63 AMG and new-generation S63 AMG sedans all boast standard-equipment 4MATIC for 2014. Distributing engine torque through all four wheels instead of just two has proven to be the best possible way to get power to the road, especially with high-performance cars. With only half the torque at each wheel (but twice the wheels receiving power), wheel spin is noticeably reduced, so acceleration and handling are even better. For example, with 4MATIC, the CLS63 AMG S-Model now accelerates from zero to 60 mph in an eye-bulging 3.6 seconds (est.).
As modern all-wheel-drive systems become more refined, they are becoming increasingly 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.
In addition to conventional differential units at the front and rear that distribute power to the left and right wheels, the Mercedes-Benz 4MATIC system uses a center differential to distribute engine torque to the front and rear wheels. And, the center differential is equipped with a "breakaway" clutch that provides the traction benefits of a limited-slip differential while allowing the front wheels to rotate faster in turns. In addition, the system uses an innovative four-wheel traction control system to limit wheel spin when conditions are slippery, allowing power to go to the wheels with more grip.
The 4MATIC system is cleanly integrated into the automatic transmission so it fits right into the standard body and utilizes the existing front suspension. Fuel efficiency has been optimized, due to a number of innovative measures that minimize the energy needed to turn the extra gears and shafts.
World's First Four-Door Coupe
Possibly the most striking Mercedes-Benz in the line-up, the CLS coupe combines the emotional appeal and dynamic design of a conventional two-door coupe with the comfort and functionality of a four-door sedan. The CLS fits between the S-Class-based CL and the E-Class two-door to form a family of Mercedes coupes that makes efficient use of existing chassis and powertrain layouts while preserving their unique individual identities.
All CLS coupes are equipped with electrically assisted power steering and a seven-speed automatic transmission with paddle shifters. Standard Mercedes safety technology includes PRE-SAFE, ABS anti-lock brakes with Brake Assist, ATTENTION ASSIST and ESP electronic stability control. DISTRONIC PLUS with PRE-SAFE Brake is optionally available, as well as Active Blind Spot Assist and Active Lane Keeping Assist.
Eco Start-Stop System
Now standard on all CLS coupes for 2014, an innovative Eco Start-Stop system improves engine efficiency by more than 20 percent. Whenever the car stops in "D" or "N" with the brake pedal depressed, the engine is automatically turned off to save fuel. As soon as the driver touches the accelerator pedal, the engine computer decides which piston is in the best position for first ignition, and the direct fuel injection and multi-spark systems work with a starter motor to re-start the engine almost instantly.
Fuel-Efficient Seven-Speed Transmission
The CLS550 features a seven-speed automatic transmission with an advanced torque converter lock-up clutch that provides optimal fuel mileage, responsive driving, quiet operation and impressive durability. The transmission is also designed to work best with a new type of low-viscosity ATF transmission fluid – colored blue instead of the usual red. Together with special planetary gears, bearings and internal seals, the "FE-ATF" fluid provides less friction and improved fuel mileage. Lower hydraulic pressure and enhanced electronic software helps provide even smoother shifting.
Innovative MCT Transmission
The high-performance CLS63 AMG and it S-Model sibling feature an AMG-developed MCT (multi-clutch technology) sports transmission with an innovative start-up clutch instead of a conventional torque converter. Providing the direct feel of a manual transmission with the convenience of an automatic, the MCT seven-speed transmission offers impressive versatility and faster shift times.
In addition to larger brakes and wider wheels and tires, the CLS63 AMG also sports a unique combination of steel coil springs at the front and AIRMATIC suspension at the rear, which provides especially responsive handling from the front suspension, while AIRMATIC at the rear maintains consistent ride height, regardless of load.
Along with a tubular front stabilizer bar, the CLS63 AMG is fitted with special front control arms and wheel hub carriers that provide wider track and more negative camber for even better grip in high speed curves. The CLS63 AMG rear suspension includes new track rods and push-pull rods as well as more rigid sub-frame mounts that all contribute to enhanced cornering.
Direct-Injection Engines
The range of biturbo V8 engines in the CLS coupe feature direct fuel injection, twin turbochargers and multi-spark ignition. The two V8 engines in the CLS are similar, with 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.
The CLS engines make use of industry-leading electronic fuel injectors that spray gasoline directly into the combustion chambers. Featuring a piezo-ceramic crystalline element that changes shape 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.
Multi-Spark Works with Multi-Squirt
Working together with the spray-guided 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 its companion direct fuel injection system.
Refined Variable Valve Timing
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.
More Efficient Cam Chain Drive
Smaller valve timing adjusters are made possible by a revised cam chain drive, 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 inactive. As engine speed and load increases, oil pressure rises, and the oil spray nozzles are turned on. In this way, less energy is used when less cooling and lubrication is needed.
Three-Phase, Low-Load Cooling System
Even the cooling system is significantly refined, beginning with a two-stage flow circuit through the cylinder head. This 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, coolant also circulates through the radiator. Coolant circulation through the heating system for the car's interior is controlled separately.
The Building Blocks
Assembling the biturbo V8 engine underscores its efficient design. An exceptionally stiff forged-steel crankshaft is bolted into a pressure-cast aluminum block, and an aluminum oil pan also contributes to block rigidity.
Aluminum pistons are mounted on the connecting rods, then slid into the silicon-aluminum sleeves, which are an integral cast-in part of the block. Connecting rods must be made in two pieces for assembly on the crankshaft, and Mercedes engines use hollow, forged steel rods that initially are made in one piece, then hydraulically "cracked," instead of being machine-cut and reground. The irregular fracture provides a very strong, durable fit, even at high engine speeds, and shortens the production process since re-grinding isn't necessary. The two cylinder heads are bolted onto the block, and twin camshafts are installed in each head, with cam drive chains looping around the intake and exhaust cam sprockets. Double-wall piping keeps the exhaust air as hot as possible leading to a catalytic converter below each cylinder bank.
Advanced COMAND
In the cabin, the COMAND system comes with a seven-inch color display, hard-drive GPS navigation, a ten-gigabyte music storage hard drive, an SD card slot, voice control and a six-disc CD/DVD changer.
The system includes a Bluetooth interface for wireless audio streaming and hands-free phone operation, HD/AM/weatherband radio, an FM phase-diversity twin tuner, Sirius-XM satellite radio and a USB port in the center console. The navigation system offers many advanced features, including a 3D city-map display, a compass overlay and the ability to show alternate routes before choosing as well as to record routes while driving.
mbrace2
Mercedes-Benz was the first manufacturer to make emergency calling a standard feature, and its mbrace2 system represents the next generation of telematics innovation that gives drivers top-of-the-line features related to safety, infotainment, personal assistance and vehicle care. Standard equipment on the new CLS, mbrace2 includes the ability to remotely update all software modules via cloud networks, so mbrace2 users always have the latest technology in their vehicles and at their fingertips. New services are also added to the mbrace2 Mobile Application, which is compatible with both iPhone and Android smartphones.
