2011 Mercedes Benz Glk Class Glk 350 4matic

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2011 Mercedes Benz Glk Class Glk 350 4matic

The 2011 Mercedes-Benz GLK 350 4MATIC, a compact luxury SUV, represented Mercedes-Benz's entry into a rapidly growing segment. While its boxy styling may not have appealed to everyone, its engineering was undeniably robust and refined. This guide delves into the technical aspects of the GLK 350 4MATIC, exploring its engine, transmission, all-wheel-drive system, suspension, and braking system.

Engine: The M272 V6

At the heart of the 2011 GLK 350 4MATIC resides the M272 E35 engine, a naturally aspirated 3.5-liter V6. This engine is a member of Mercedes-Benz's M272 engine family and is constructed with an aluminum engine block and cylinder heads, contributing to weight reduction. The M272 features dual overhead camshafts (DOHC) and four valves per cylinder (24 valves in total), optimized for both performance and efficiency. This configuration allows for precise valve timing, enhancing engine breathing and improving power output across the rev range.

Key Engine Features:

  • Displacement: 3.5 liters (3498 cc)
  • Bore x Stroke: 92.9 mm x 86.0 mm
  • Compression Ratio: 10.7:1
  • Fuel Injection: Multi-port fuel injection (ME 9.7 engine management system)
  • Power Output: 268 horsepower (200 kW) at 6,000 rpm
  • Torque Output: 258 lb-ft (350 Nm) at 2,400-5,000 rpm

The M272 engine utilizes a sophisticated ME 9.7 engine management system. This system constantly monitors various engine parameters, including intake air temperature, throttle position, crankshaft position, and camshaft position, to optimize fuel injection and ignition timing. It also incorporates adaptive learning capabilities, allowing the engine to adjust to varying driving conditions and fuel qualities. The engine's variable intake manifold also plays a crucial role in optimizing performance. By changing the intake runner length based on engine speed, the system enhances both low-end torque and high-end power.

The use of aluminum in the engine block and cylinder heads contributes significantly to the GLK's overall fuel efficiency and handling. Reducing weight is a key engineering principle.

Transmission: 7G-TRONIC Automatic

The 2011 GLK 350 4MATIC is equipped with Mercedes-Benz's 7G-TRONIC seven-speed automatic transmission. This transmission, designated as the 722.9, is electronically controlled and hydraulically actuated. Its primary function is to efficiently transfer the engine's power to the wheels while providing a wide range of gear ratios for optimal acceleration, fuel economy, and cruising comfort.

Key Transmission Features:

  • Number of Gears: 7 forward, 2 reverse (though only one reverse gear is typically used)
  • Type: Electronically controlled automatic with torque converter
  • Shift Modes: Comfort (C), Sport (S), and Manual (M)
  • Torque Converter: Features a lock-up clutch for improved fuel efficiency

The 7G-TRONIC transmission utilizes a planetary gear set design, which allows for a compact and efficient packaging. Its electronic control unit (ECU) communicates with the engine management system to optimize shift points based on driving conditions and driver input. The driver-selectable shift modes (C, S, and M) provide a degree of customization, allowing the driver to prioritize fuel economy (Comfort), performance (Sport), or direct control (Manual). In Manual mode, the driver can shift gears using the shift lever or optional steering wheel-mounted paddle shifters.

The torque converter is an integral part of the automatic transmission, responsible for smoothly transferring power from the engine to the transmission. The lock-up clutch, which engages at higher speeds, eliminates slippage within the torque converter, further improving fuel efficiency.

4MATIC All-Wheel-Drive System

The "4MATIC" designation indicates that the GLK 350 is equipped with Mercedes-Benz's all-wheel-drive system. This system is designed to enhance traction and stability in various driving conditions, particularly on slippery surfaces such as snow, ice, or gravel.

4MATIC System Overview:

  • Type: Full-time all-wheel drive
  • Torque Distribution: Typically 45% front, 55% rear (fixed split)
  • Differential: Open front and rear differentials with electronic traction control (4ETS)

The 4MATIC system on the 2011 GLK 350 utilizes a single-speed transfer case to distribute torque between the front and rear axles. The torque split is fixed at 45% to the front wheels and 55% to the rear wheels, providing a slightly rear-biased driving feel. While the system uses open differentials at both the front and rear axles, it relies on Mercedes-Benz's 4ETS (Electronic Traction System) to simulate the effect of limited-slip differentials. When a wheel loses traction, 4ETS applies braking force to that wheel, transferring torque to the wheels with more grip.

4ETS Functionality: This system uses the ABS sensors to detect wheelspin. Upon detecting wheelspin, the system automatically applies the brakes to the spinning wheel. This process effectively transfers torque to the wheel with more grip, allowing the vehicle to maintain traction and continue moving forward. The 4ETS system works seamlessly and automatically, requiring no driver intervention.

Suspension System

The GLK 350 4MATIC features an independent suspension system on both the front and rear axles, designed to provide a comfortable ride and responsive handling.

Suspension Components:

  • Front Suspension: MacPherson strut with lower control arms, coil springs, and stabilizer bar
  • Rear Suspension: Multi-link independent suspension with coil springs and stabilizer bar
  • Dampers: Gas-filled shock absorbers

The MacPherson strut front suspension provides a good balance between handling and ride comfort. The multi-link rear suspension allows for independent control of wheel movement, further enhancing ride quality and handling precision. The stabilizer bars, located at both the front and rear axles, reduce body roll during cornering, improving stability. The gas-filled shock absorbers provide damping force to control suspension movement and absorb road imperfections.

Braking System

The GLK 350 4MATIC is equipped with a four-wheel disc brake system with anti-lock braking system (ABS), brake assist (BAS), and electronic stability program (ESP).

Braking System Components:

  • Brakes: Four-wheel disc brakes with ventilated front rotors
  • ABS: Anti-lock braking system
  • BAS: Brake assist
  • ESP: Electronic stability program

The four-wheel disc brakes provide ample stopping power. The ventilated front rotors dissipate heat more effectively, reducing brake fade during heavy braking. The ABS prevents wheel lockup during hard braking, allowing the driver to maintain steering control. The BAS detects emergency braking situations and automatically applies maximum braking force to reduce stopping distance. The ESP monitors vehicle stability and intervenes by applying brakes to individual wheels to prevent skidding and maintain directional control. These systems work in concert to provide a safe and controlled braking experience.

In conclusion, the 2011 Mercedes-Benz GLK 350 4MATIC is a well-engineered vehicle that blends luxury with capability. Its robust engine, sophisticated transmission, capable all-wheel-drive system, and advanced safety features contribute to a refined and confidence-inspiring driving experience. Understanding the technical aspects of these systems provides a deeper appreciation for the engineering that went into creating this compact luxury SUV.

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