Automobile Chassis Air Suspension Core Reveal: In-Depth Analysis of Air Springs

Air Suspension System is a technology that adjusts the vehicle’s height and suspension stiffness by changing the air pressure inside air springs. This allows it to better adapt to road conditions and different driving modes, improving comfort and handling. Compared to fuel vehicles of the same class, electric vehicles are heavier, have a rearward center of gravity, and a larger initial torque. These factors place higher demands on the vehicle’s suspension. Especially in new energy vehicles, the power battery increases the vehicle's weight, and the air suspension optimizes airflow underneath the body, enhancing battery cooling and reducing road impact. As vehicle intelligence improves, combining sensors with innovative suspension technology allows the system to predict road conditions and adjust for better comfort and handling, making air suspension increasingly important in mid-range and high-end cars.

Introduction to Air Suspension Systems

Air suspension systems include several key parts: air springs, air supply units (such as compressors, tanks, and valves), electronic control units (ECUs), and sensors (body height, acceleration sensors, etc.). Air springs usually work with variable damping dampers, with compressors and air springs being the most valuable and technically challenging components. The main purpose of air suspension is to adjust stiffness and body height by controlling air pressure in the springs based on road conditions and driving needs, improving the vehicle's comfort and stability. Air suspension is commonly used in luxury sedans and high-end electric vehicles, where it enhances dynamic response, comfort, and handling on complex road surfaces.

Key Component: Air Spring

The air spring is the core part of the air suspension system, using air pressure inside a rubber airbag as its elastic force. The air spring adjusts body height and suspension stiffness by changing the air inside the airbag. In the front, air springs and dampers are typically a single unit, while at the rear, they are often arranged separately. The compressed air in the spring acts as an adjustable elastic element that can vary stiffness based on the vehicle's needs for an optimal driving experience.

1. Body Height Adjustment: Inflating the airbag raises the vehicle’s ground clearance, improving off-road capability. Deflating it lowers the vehicle, enhancing stability, reducing wind resistance, and improving fuel efficiency.
2. Comfort and Load Adaptability: The air spring’s non-linear stiffness maintains a comfortable ride under different load conditions. When the load changes (e.g., from empty to fully loaded), the spring adjusts its stiffness to keep driving comfort consistent.
3. Vibration Suppression: The rubber in air springs helps isolate high-frequency vibrations and noise from the road. The rubber material and air’s properties provide better sound insulation, making the cabin quieter and more comfortable.

Technical Barriers of Air Springs

The core of the air spring lies in its rubber bladder design and manufacturing process. The bladder's durability directly affects the air spring's service life. Air springs are subjected to repeated movements and must withstand extreme temperatures, making durability crucial. The bladder consists of an inner rubber layer, an outer rubber layer, a cord layer, and wire rings vulcanized into place.

1. Inner and Outer Rubber Layers: Made of high-performance rubber that is weather- and oil-resistant. The inner layer is essential for ensuring the air spring is sealed.
2. Cord Layer: This supports most of the air spring’s load and consists of two cross-patterned layers. The cord material is key to the spring’s durability and compression resistance.
3. Wire Coils: Located at the ends of the air spring, these wire coils are vulcanized to ensure a long-lasting seal with no air leaks.

Developing air springs requires extensive testing, from optimizing the rubber formulation to refining vulcanization parameters. The final solution is reached through numerous fatigue tests. The assembly process, especially the buckling procedure, presents technical challenges that directly impact air spring performance. As a result, the bladder’s durability, sealing, and noise control are critical technical barriers, with even higher standards for high-end luxury brands.

Types and Development of Air Springs

There are three main types of air springs used in automobiles: single-chamber, dual-chamber, and triple-chamber. Each type differs in structural complexity and performance.

1.Single-Chamber Air Spring: This is the most common type, with a simple structure and low cost. It’s widely used in domestic passenger cars. However, its stiffness adjustment range is limited, meaning it can’t offer a more dynamic driving experience.

2. Dual-Chamber Air Spring: This adds a secondary air chamber, allowing for different driving modes. By adjusting the main and secondary chambers, the vehicle can switch between sporty and comfortable modes. It’s more complex and costly, so it’s mainly found in high-end vehicles.

3. Triple-Chamber Air Spring: With three chambers and two solenoid valves, this design offers four stiffness levels, providing the best performance. Triple-chamber air springs are typically found in luxury models like the Porsche Cayenne and Mercedes-Benz GLC.

Market Pattern of Air Springs

The global air spring market is largely dominated by overseas suppliers like Continental, Vibracoustic, and Firestone, which have strong expertise in rubber product manufacturing. Recently, domestic suppliers like KH Automotive and Baolong Automotive have also made progress in the development and production of air suspension systems.

1. Overseas Suppliers

Continental AG: A leader in the air suspension field, supplying systems for luxury brands like Audi and Volkswagen.

Vibracoustic: A subsidiary of Freudenberg, it holds a significant share of the global air spring market, with expertise in spring skin material.

Firestone: Known for its strong market share in China, particularly in commercial vehicles and buses.

2. China Suppliers

KH Automotive: Based in Zhejiang, it focuses on R&D and production of air suspension systems, particularly for domestic EV brands.

Baolong Automotive: Headquartered in Shanghai, this company has achieved mass production of air springs through product development and market expansion.

Tuopu Group: A major player in the research and development of air suspension systems, partnering with several mainstream manufacturers.

Development Trends of Air Springs

As the demand for vehicle comfort and handling continues to rise, the application of air springs is expanding. Future developments are expected to focus on:

1. Multi-Chamber Structures: Evolving from single- to multi-chamber designs for greater stiffness adjustment, offering better adaptability to various driving modes.
2. Intelligent Adjustment: Air springs will work with vehicle intelligence systems to collect real-time data and adjust air pressure for improved comfort and handling.
3. Lightweight and Durability Improvements: As environmental regulations tighten, manufacturers are focusing on making air springs lighter and more durable through better rubber formulations, cord materials, and production processes.

Conclusion

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