Pre-vehicle design largely determines the comfort of the vehicle

Gu Yan, Senior Expert, Technical Center, Shanghai Automotive Co., Ltd.

Gasgoo.com: With the increase in consumer comfort requirements for automobiles, the control of NVH (noise, vibration, and comfort) of the vehicle has always been a topic discussed and studied by technicians. Do you think that the current NVH control process is the largest? What are the problems and challenges?

Gu Yan: The biggest problems at the moment are noise sources, control of engine powertrains and accessories. Everyone commented that the good vibration noise control in Japan is due to the fact that the engine is good, the engine is light, and the vibration is relatively small, so the whole is easier to control. Another point is the issue of teamwork and process management. Because the entire vehicle noise control is the control of the entire process of R&D, procurement, manufacturing, and sales, it is fed back to the R&D, procurement, manufacturing, and other departments to continuously improve the process through the sales end.

Gasgoo.com: In the NVH control process, do you think the most effective control method is NVH's early design? The most critical technical point is the application of innovative materials or the solution to other key technical issues?

Gu Yan: First of all, it must be market-oriented. For example, the market needs cars like Hyatt and Long Yi. Then use this as an early analysis of competing cars to understand what their vibration and noise conditions are and what we need to do to achieve this goal. do? For example, in order to achieve the goal of a comfortable brand, vibration noise needs to achieve what kind of goals, while forming the corresponding data goals. Followed by how to implement data, you need to form a corresponding strategy. For example, to achieve such standard noise, then we need two seals, and the engine mount must have a hydraulic mount. After the strategy is formed, it needs to be decomposed into the performance requirements of various components. For example, if the engine requires hydraulic suspension, then the performance and stiffness of the hydraulic suspension need to meet certain standards. Then with the supplier to design and develop the corresponding requirements of the product, after the design is completed and installed on the car to check whether there are still problems. The vibration noise needs to be constantly adjusted. It also requires a lot of CAE work in the early stage.

Innovative materials cannot be used for innovative materials but innovative materials. In fact, traditional materials are very good because automobiles are not a very high-tech thing. They do not mean that they need to use innovative materials to represent technology. Therefore, many parts manufacturers are willing to introduce innovations. Material products, but the actual effect is the need to balance, for example, the performance is indeed very obvious, the cost is not high or low, then the whole car factory will be happy to use, if the cost is very high and the effect is not obvious that it is not very happy to apply. It is generally better to consider how to do it on the basis of existing materials.

Gasgoo.com: What position do you think the NVH control of the car body is currently in the NVH control process of the vehicle?

Gu Yan: The body NVH control is very important. The body provides a shell to protect the occupants for collision. NVH also plays a protective role and plays the role of sound insulation. The body is a very good natural acoustic material, such as the body. Sheet metal is very heavy, it is a very good natural sound insulation material. However, it is very important for car body design personnel not to consider the sound insulation material, because the car body is also a structure that carries a lot of pressure, noise and vibration from the outside world. Sealing technology is a very important magic weapon in the body NVH control, in addition to sound insulation, improve structural capacity, improve the body steel and other methods. At the same time, the purpose of reducing noise is to reduce the friction between body accessories by optimizing the design of the body.

Gasgoo.com: Statistics show that about one-third of the vehicle failures are related to the NVH problem of the vehicle. Nearly 20% of the research and development expenses of major companies are spent on solving NVH problems. Do you understand the current situation?

Gu Yan: The proportion of NVH problems in the whole vehicle breakdown problem has not been counted, but the NVH problem has always existed, and consumers have complained that the problem is abnormal noise. Abnormal sound problems can be generally divided into two kinds: one kind of situation is that abnormal noise is abnormal, for example, a certain screw loose sound of the engine, the user's revelation is that the car has problems, need repair. Everyone thinks that NVH is pejorative, but in fact NVH should be neutral, except that the sound is not noise. The sound just gives the user a kind of information. The user can only feel the information through vision, touch and smell. The problem that is reflected is the NVH problem, but in fact it is caused by an abnormality in one part of the car. So this type of abnormal sound problem is completely a matter of component damage, abnormal work, rather than the NVH control problem. Another part of the situation is a user complaint caused by the sound caused by the failure of parts and components. Such complaints are NVH control problems. For example, common NVH complaints include brake noise. Most of the research and development costs of NVH problem control are spent on the development of parts and components. Because in the early development, there are requirements for noise reduction and shock absorption of parts, so more expenses are invested in the research and development of parts and components. Another part of the cost is the technical department's test costs.

Gasgoo.com: In the course of improving the NVH characteristics of automobiles, the current rise in automobile raw materials will have a great impact on the choice of vehicle NVH materials.

Gu Yan: There are impacts. OEMs usually use cheap materials as much as possible. This is something that some parts manufacturers do not want to see. Of course, sometimes good materials do not necessarily represent expensive. Not only the technical department but also the purchasing department will make comprehensive decisions to determine the overall choice for cost control. In fact, the application of materials is only one aspect of NVH control. It is important to look at the design. If the design is good, cheap materials can do well. In addition, if the source of the engine can be controlled well, cheap materials can be applied very well.