The crumple zones, seatbelt tensioners and airbags in cars have moved beyond the realm of low-end products and have begun to enter the ranks of high-tech products. These new safety technologies are fully reflected in the new Mercedes-Benz CL sedan.

The most outstanding automobile safety protection system is the active safety protection system Presafe safety warning device designed after summarizing the experience of Mercedes-Benz S-Class sedans. Its reaction is as fast as a reflector, and it can provide safety protection similar to evaluating intuition. Mercedes-Benz applies this automation technology to automobile manufacturing because the results of modern traffic accident analysis and research show that two-thirds of serious traffic accidents are related to the driver's driving skills. Based on this understanding, Mercedes-Benz realizes that it should adopt more advanced "conditional reflex technology", that is, take more effective measures. In the Mercedes-Benz CL sedan, the vehicle dynamic driving data provided by the ESP system and the information provided by the 77GHz long-range radar that adjusts the distance and speed of the vehicle and the 24GHz short-range radar can accurately reflect the driving conditions of the vehicle. The electronic system of the car evaluates and analyzes this information and data, and makes the following adjustments to the active spine protection system to prevent all possible collision accidents:

□ Adjust the height and length, as well as the tilt angle of the front passenger seat headrest and the car seat backrest to ensure that the seat belts and airbags can play their protective role normally;

□ Create the best protective air pressure in the air cushion of the multifunctional protective seat to provide better safety protection for the driver and co-pilot;

□ Close the side windows and movable roof at the front seats to prevent the occupants from being thrown out of the car, and also to prevent foreign objects from entering the car; in addition, the head airbags of the front seats and side windows can better play a role in safety protection;

□ When the driver of a Mercedes-Benz CL car steps on the brake pedal, the optimal braking force is calculated and the braking preparation is quickly made.

□ If the driver does not respond in time to the dangerous situation identified by the automatic control system, the brake assist system will automatically delay the braking measures after warning the driver: braking at a maximum braking deceleration of 0.4g, equivalent to a deceleration of 4m/s2 or 40% of the maximum braking power. This is also a very clear and last warning signal to the driver, requiring him to personally complete the final full braking. The braking function of the brake assist system and the Presafe safety warning system can be provided to users as optional components.

Night Vision System

The night vision system provided by Bosch can ensure that the car can see everything clearly even in the dark. It uses the two headlights in front of the car to emit infrared rays that are invisible to the human eye for observation. The infrared rays reflected by obstacles are captured by the infrared camera installed inside the car window glass. The CMOS complementary metal oxide semiconductor sensor and infrared camera electronically attenuate the interfering light, while improving the clarity of other images, so that the image reflected by the obstacle is clearly visible.

Working conditions of active safety protection system at night: Mercedes-Benz CL sedan uses night vision system produced by Bosch

Mercedes-Benz believes that grayscale image generation technology has more advantages than the active infrared technology used by BMW. Traffic signs, pedestrians, bicycles , cargo dropped from vehicles or other dangerous sources can be clearly seen on the display screen on the dashboard, with a maximum recognition distance of 200m. However, this information-rich display screen also exposes a weakness of the system, that is, it is difficult for the driver to find the dangerous source with a brief glance, and if the image on the display screen is carefully studied or viewed multiple times, it will hinder driving safety.

The night vision system developed and produced by Autoliv used by BMW is a night vision system based on another principle. BMW abandoned infrared headlights and only relied on thermal imaging cameras to monitor obstacles in front of the car. It receives infrared rays reflected by obstacles that are hotter than surrounding objects. Generally speaking, they are thermal radiation rays reflected by the high body temperature of people or animals. Since only the images generated by high-temperature objects are displayed on the screen, the amount of information it reflects is significantly reduced, making it easy to identify the source of danger. However, its disadvantage is that it cannot provide information about cold obstacles, such as stones lying across the road.

The two systems combined are a strong competitor to modern bismuth-xenon headlights. The night vision system of the Mercedes-Benz CL sedan can see obstacles 200 meters away at night, and the night vision system of BMW can see 300 meters away.

The new rural headlight (right) clearly illuminates the roadside and shines farther and brighter on the driver's side than the original headlight

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The Mercedes-Benz CL sedan uses not only bismuth-xenon headlights, but also networked these headlights through an electronic control system. The control system illuminates the headlights under the control of control data according to different driving conditions, so that the lighting emitted by the headlights is suitable for the requirements of the driving environment. For example, the so-called "country road lighting" in the Mercedes-Benz CL sedan replaces the original anti-glare lamps, which can illuminate the roadside more clearly and make the lighting on the driver's side farther and brighter than before. When the speed exceeds 90km/h, it automatically switches to the lighting state of the highway lights, increasing the driver's sight distance by 60%. The power of this bismuth-xenon headlight has also been increased from the original 35W to 38W. When the speed reaches 110km/h, the lighting intensity of the bismuth-xenon headlight on the driver's side is slightly increased, and the high beam is turned on. The focusing plate in front of the high beam can form a clear boundary between light and dark on the road surface, effectively avoiding dazzling the other vehicle. According to Mercedes-Benz, the illumination distance of this new highway light can reach 120m, which is 50m farther than the traditional anti-glare light.

The fog lights will illuminate when the vehicle speed reaches 100 km/h and the fog lights are turned on. The bismuth-xenon headlight on the driver's side rotates outward by 8°, and the light beam is also tilted downward. This prevents the driver from being dazzled by the light reflected back from the fog. The turn signal in the Mercedes-Benz CL car's headlight system has also added new functions. It is the first headlight to adopt the legally recognized active headlight adjustment technology ECE standard.

The new Mercedes-Benz CL sedan also features the Ultrasonic Parking Assist system, which is standard equipment. This system uses an expensive reversing camera installed in the rear cargo lid; the image from the camera is displayed on the central display. The reversing controller calculates the best reversing path and shows the optimal reversing line on the display with colored lines.

The Presafe safety warning system reports the risk of collision to the driver. As the possibility of a collision increases, the acoustic and optical warning signals become more and more urgent.

During the reversing control process, six radar sensors help complete the reversing process and continuously monitor the distance within 11 meters behind the vehicle, which is much larger than the traditional ultrasonic parking control system. The distance between the four corners of the vehicle and obstacles can be displayed on the display screen of the dashboard or on the ceiling above the rear of the vehicle, and an alarm is also used to remind the driver to pay attention.

Safety in use

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Mercedes-Benz has, as always, attached great importance to operational safety. The frame structure of the new Mercedes-Benz CL sedan also adopts a composite material design, with a combination of steel, aluminum, manganese and plastic materials. However, it is obvious that more steel is used, replacing aluminum. The only aluminum parts are the engine hood, front fenders, door skins, front and rear bumper brackets, the baffle behind the rear seat backrests and the rear cargo box partition. In the old model, the car's outer skin and some structural parts still used a lot of light alloy materials. Similarly, Mercedes-Benz has reduced the number of plastic parts in the CL model, and only uses these materials in the trunk lid and spare wheel module. It can be observed that all parts that can excite self-vibration, such as the front plastic fenders, have been eliminated in the new model. They are replaced by aluminum. The frame structure inside the door is made of manganese alloy.

Among the steels used, the proportion of high-strength and ultra-high-strength deep-drawn alloy steels has increased (steel accounts for 44% of the frame weight, deep-drawn steel accounts for 26%). In high-load components, Mercedes-Benz even uses heat-resistant steel with a tensile strength three times higher than that of traditional steel.

Adhesives for bonding frame materials complement joining technologies such as spot welding and laser welding as well as technologies without or with minimal processing. They allow bonding of large sheet materials, thereby increasing their load-bearing and force-transmitting capacity. The number of brazing and MAG gas shielded welding connections between sheet parts is also significantly reduced.

Safety protection in case of collision

When a vehicle collision occurs, the front and rear aluminum stamped curved beams absorb part of the collision energy together with the collision buffer. A slight collision will not cause any damage to the frame. In the bonded frame components, the impact force during the collision is transmitted along multiple vertical and horizontal planes (such as along the longitudinal beams, side frames, middle bottom channel, rear axle frame). This energy dispersion has a good protective effect on the occupants of the Mercedes-Benz CL sedan and also reduces the damage to the other party in the accident.

Using radar sensors and assisted parking control systems to tell the driver how to park

The active spinal protection system in the car is controlled by the car controller. The controller calculates the severity of the accident based on the data from 11 sensors and adjusts the angle of the seat back, such as the angle of the front passenger seat back, according to actual needs. Depending on the load (whether there is someone in the seat, whether it is an adult or a child, and the weight of the person), the front passenger airbag, side airbags, seat belts and other safety protection mechanisms start to work, or not work at all. The sensors in the doors of the Mercedes-Benz CL sedan are also an innovation. They control the operation of the side airbags based on the changes in the air pressure inside the door, which reacts much faster than traditional control methods.

In addition to eight airbags in the front, sides and windows, the four occupants of the Mercedes-Benz CL are protected by three-point automatic seatbelts with belt tensioners and belt force limiters. The Mercedes-Benz CL will not "abandon" its occupants after a collision. For example, after a certain collision, it will automatically cut off the engine's fuel supply system and automatically turn on the warning light system. After the airbag pops out, all side windows will open a narrow gap to facilitate ventilation and exhaust in the car; at the same time, all door locks will automatically open. In addition, according to Mercedes-Benz designers, the doors can also be stuck by the fenders to prevent the occupants from falling out of the car. The markings on the rear window will tell emergency personnel: where to disconnect the car's C-pillar to rescue the occupants in time.