Air suspension applications are declining, and local suspension system suppliers are actively exploring breakthroughs

In recent years, with the vigorous development of my country's new energy vehicle market and the continuous efforts of domestic brands in the field of high-end new energy, a more advanced suspension system has begun to appear frequently in new high-end models of domestic brands. It is the air suspension system that is currently very popular in the market.

Compared with ordinary suspension systems, air suspension systems can significantly improve vehicle handling and comfort by controlling vehicle height, vehicle inclination, and adjusting vibration damping force, while also improving the intelligence level of the vehicle chassis. Based on this, since 2017, high-end new models under independent brands such as NIO, Hongqi, Lantu, and Zeekr have begun to be equipped with air suspension systems one after another, and use it as a major promotional point.

Electronically controlled shock absorbers, the perfect partner for air suspension

From the perspective of system composition, the biggest change in the air suspension system is that the coil springs currently commonly used in passenger cars are replaced with air springs. However, in fact, the system has a complex structure, mainly including air springs, air supply units (compressors, air tanks, distribution valves, etc.), control systems, air pipelines, etc. In addition, the air suspension system also needs to be used with electronically controlled damping shock absorbers.

Passenger car electronic suspension system structure; Image source: Aerospace Dingxin

It is understood that compared with ordinary shock absorbers, the electronically controlled shock absorber system has achieved a major breakthrough from traditional mechanical control to electrical control, and has better performance in vehicle comfort and handling stability. Usually, when evaluating the chassis performance of a vehicle, the industry will consider the two aspects of smoothness and handling stability. Smoothness determines the comfort of the vehicle, and handling stability emphasizes the safety of the vehicle, but these two indicators often appear in opposition. Ordinary passive shock absorbers can only choose a fixed state between the two, while electronically controlled shock absorbers can perfectly balance the smoothness and handling stability of the vehicle. When the vehicle needs smoothness, it will give a damping force output for smoothness, and when it needs handling stability, it will give a damping force output that satisfies handling stability.

Specifically in the air suspension system, the electronically controlled shock absorber and the air suspension promote and enhance each other: on the one hand, the air suspension can better isolate vibrations and provide better comfort based on the shock absorber; on the other hand, the electronically controlled shock absorber can match the corresponding damping force when the air suspension height is raised or lowered, providing a good frequency deviation and safety state for the entire vehicle; in addition, the electronically controlled shock absorber can share controllers and sensors in the air suspension system, providing the entire vehicle with better smoothness and handling stability performance.

Seizing market opportunities, local suspension system suppliers actively explore

In the field of passenger cars, the air suspension system is an advanced configuration, which has been mostly used in luxury brand models such as Porsche, BBA, and Volvo. The price of these luxury models with standard air suspension systems is more than 700,000 yuan, and the optional ones start at 500,000 yuan.

The reason why models equipped with air suspension systems are so expensive is largely due to the limited supply of the system and the technical barriers to related components. For example, foreign suppliers of electronically controlled shock absorbers have become the main suppliers of this component because they started earlier and have more advanced technology, while domestic companies rarely have the opportunity to get involved.

Yan Leiming, executive director of Zhejiang Dingxin Aerospace Technology Co., Ltd. (hereinafter referred to as: Aerospace Dingxin), analyzed the reasons for the supply situation of electronically controlled shock absorbers and pointed out that there are three main reasons:

First, from the demand side, most electronically controlled shock absorbers are used in high-end models. In the past, high-end models were mostly joint venture models, and joint venture models habitually use products from foreign-funded enterprises.

Second, the mid-to-high-end shock absorber products have long been dominated by foreign companies. Domestic shock absorber companies started late, and there is a gap in technology and production processes with foreign countries, and they have no say in the market;

Third, shock absorbers, especially electronically controlled shock absorbers, are relatively complex and are the most frequently used automotive components. The springs, piston rods, valve plates, rubber parts, etc. of the shock absorbers all have an impact on the product.

Fortunately, with the development of domestic independent brands and the rise of new car-making forces, the application of air suspension systems is gradually decreasing, and at the same time, it has created a large number of market demand points for local companies in the field of electronically controlled shock absorbers. Therefore, seizing this development opportunity and achieving independent breakthroughs in electronically controlled shock absorbers or even domestic substitution has become an important issue for all local suppliers.

As a new explorer of new technologies in China's automotive intelligent suspension systems, Liao Anzhi, head of research and development of Aerospace Dingxin's intelligent suspension systems, said that from a technical perspective, the electronically controlled shock absorber itself is not difficult, and it can even be said that there are no barriers in terms of professional technology.

"This technology was proposed abroad in the last century, but it is difficult to improve the performance of key components, ensure consistency, control costs, and especially adapt to different vehicle models. For example, the solenoid valves used in shock absorbers, the performance of the current domestic solenoid proportional valves needs to be further improved. In addition to devices, the control algorithm of the electronically controlled shock absorber is also one of the difficulties of the electronically controlled shock absorber." Liao Anzhi said.

Image source: Aerospace Dingxin

It is worth mentioning that Aerospace Dingxin has made breakthroughs in the face of difficulties in the development of domestic electronically controlled shock absorbers. According to reports, Aerospace Dingxin is the first in China to use a new digital valve to replace the traditional proportional valve for shock absorber damping control, and has achieved modular development of all components of the electronically controlled shock absorber system, which can quickly respond to the development needs of the OEM. At present, the company has carried out cooperative pre-research with many OEMs and is carrying out synchronous development of electronically controlled shock absorber systems with several OEMs.

After years of R&D and continuous investment, Aerospace Dingxin is committed to developing its own intelligent suspension system

It can be said that the progress made by Aerospace Dingxin in the field of electronically controlled shock absorbers is a major boon to the related supporting facilities of the entire domestic automobile suspension system. As a local supplier of suspension systems and core components, Aerospace Dingxin's current breakthrough is inseparable from its deep technical accumulation.

It is understood that Aerospace Dingxin is affiliated to Sichuan Aerospace Industry Group of China Aerospace Science and Technology Corporation. Driven by the key development strategy of aerospace technology application industry, it has formed a mature product system with automotive shock absorber parts as the core in the automotive parts industry. Based on the research and development and production of shock absorbers, the company's R&D team has been developing electronically controlled shock absorbers since 2012, and has integrated mature and reliable aerospace technologies such as solenoid valves and electronic control systems into the development of system products, becoming one of the earliest manufacturers in China to make efforts in this field.

Image source: Aerospace Dingxin

Subsequently, the company formed an experienced and creative team to start in-depth research and development of the intelligent suspension segment. Among them, the technical research and development team composed of high-end talents such as doctors, masters, and researchers accounted for 30% of the company's total number of employees. At the same time, in order to promote the rapid conversion and implementation of scientific and technological achievements, Aerospace Dingxin actively communicated with industry experts and also conducted in-depth cooperation with domestic scientific research institutions such as Southwest Jiaotong University, Lanzhou University of Technology, and Xihua University. Adhering to the mentality of openness and cooperation, Aerospace Dingxin conducts joint research and development with car companies to quickly promote product innovation and iteration. For example, in the cooperation with the BAIC project, three iterations of the controller were completed in just 8 months.

Based on years of research and development and continuous investment, Aerospace Dingxin's self-developed DASS digital active suspension system has achieved significant improvements in intelligence and lightweight.

According to Liao Anzhi, in terms of intelligence, Aerospace Dingxin DASS can actively adjust height, stiffness, and damping, with faster response speed and better comfort. In particular, the innovative design of combining high-speed switching valves in the aerospace field with the solenoid valve drive circuit can achieve a digital valve drive response time of no more than 1 millisecond, which means that the digital valve can achieve vibration attenuation and suspension attitude adjustment, bringing more superior comfort. In terms of lightweight, for special application scenarios such as flying cars, DASS is expected to achieve a weight reduction of more than 20%.