NVH measurement technology to shape a new scheme for automobile innovation

Now, out of concern for environmental issues, countries have begun to implement increasingly stringent carbon dioxide emission regulations, which has brought earth shaking changes to the product R & D of the automotive industry. As far as automotive power system is concerned, the transformation from traditional internal combustion engine to electric powertrain makes NVH engineering development face many challenges. To this end, Qishile launched an efficient measurement solution with ultra-high flexibility to actively meet the challenges of the new era. NVH, namely "noise, vibration and sound vibration roughness smoothness", covers all aspects of vehicle sound and vibration performance. Optimizing the NVH performance of automobile or powertrain helps manufacturers produce reliable products with longer service life. Therefore, the industry pays more and more attention to these problems. In addition, optimizing NVH performance can also greatly affect the evaluation of vehicle quality by vehicle drivers and passengers. The ultimate goal of automobile innovation in the new era is to improve driving comfort, driving interest and brand image to an unprecedented level. The above changes also make NVH one of the core factors of automobile innovation. From the perspective of NVH, the characteristics of internal combustion engine and motor are fundamentally different. However, it is not difficult for even laymen to distinguish. The motion performance and mechanical power of internal combustion engine generally produce harsh mechanical sound, while the propulsion force of motor only produces soft sound similar to whistle. Now, the latter is gradually replacing the former. For the end customer, the high-frequency tone emitted by the motor is a new auditory experience, but it may not bring a pleasant feeling. On the other hand, in the process of automobile operation, the noise of internal combustion engine can bring "shielding effect"; Electric vehicles obviously do not have this feature. Therefore, the noise generated by roads, tires, wind and ventilation system is clearer, which is bound to have a negative impact on users' ride comfort. What changes will the NVH optimization of electric vehicles bring? The main tasks of NVH engineers include quantifying the noise and vibration generated by the powertrain and understanding their impact on passengers. Deepening the understanding of this problem is very important to meet users' expectations for vehicle design. According to engineering practice, noise is generally divided into two categories: structural noise and air noise. The structural noise is mainly generated by vibration. The structural noise is transmitted from the power system to the vehicle frame through bearings and installation points, affecting passengers; The air noise mainly comes from the power assembly and is transmitted through the air through the engine compartment, thus affecting passengers. It is not easy to separate the transmission paths of these two kinds of noise, but if this problem can be solved in the design stage, the NVH performance of the vehicle will be fundamentally improved. In practical application, it is not difficult to find such a phenomenon: because the power system properties of internal combustion engine and motor are different, the air noise will be significantly reduced after using motor to replace internal combustion engine. However, the noise performance of the motor may lead to some local high-frequency noise. In addition, after replacing the engine, although it is not obvious, the structural noise will also be reduced; More importantly, the low noise level has been significantly improved. In fact, the above optimization results from the great difference in dynamic behavior between motor and internal combustion engine. Therefore, the force transmission path from the powertrain to the vehicle frame is the key to improve the vehicle noise. It is imperative to measure and study this path. In addition to the above factors, the transmission of structural noise is also affected by the vehicle structure - and technological changes in this area are also under way. Electric vehicles use batteries as the energy source, and the bulky battery pack will have a great impact on the overall NVH footprint of the vehicle. At present, major OEMs are committed to improving the driving range and battery capacity of electric vehicles. Reducing the weight of battery pack is not an achievable goal in the short term. Therefore, vibration impact assessment is very important for the effective optimization of NVH performance. How to measure the vibration on the transmission path of structural noise is the primary problem to be solved urgently. If you want to effectively measure the vibration in the vibration frequency range, you must design a special acoustic solution. In addition to affecting the vehicle architecture and development process, these changes and challenges also put forward new requirements for the accuracy and reliability of the measurement chain. The first requirement is to improve the flexibility of measurement. To this end, Qishile is always ready to provide excellent, simple and easy-to-use NVH measurement solutions for automobile manufacturers and developers. Customized force measurement solutions for specific applications In order to accurately evaluate structural noise transmission, it is necessary to understand the stress at the connection between vibration source (such as powertrain) and vehicle frame. The stress analysis results are also the key input data of common processes such as body in white structure optimization, transmission path analysis (TPA) and blocking force measurement. These measurement applications require specific geometric constraints and unique working load conditions, which largely exceed the measurement capacity of traditional force sensors. In order to meet these demanding requirements, Qishile launched a customized solution based on piezoelectric (PE) measurement technology. Each scheme is customized according to specific applications, which can accurately measure the stress at the connection. PE sensor has high rigidity, so it has high natural frequency and wide measurement range, and can capture dynamic forces of different orders of magnitude. In addition, PE measurement technology also has the advantages of overload protection design and ultra long cyclic loading life. It is a powerful measurement equipment suitable for NVH measurement applications. At present, in terms of meeting the challenges brought by mobile travel, PE measurement technology can be described as an ideal solution; Even in the future, its advanced nature can not be replaced. With more than 60 years of experience in the field of PE measurement technology, Qishile provides the industry with a complete measurement solution, which can accurately measure up to six components (three forces and three moments) to meet the geometric and load requirements of each customer. Qishile solution covers a complete application process, from design, engineering to production, to commissioning and service, bringing customers a comprehensive one-stop experience.