Chapter 105: The Term "NVH"

Zhao Guoyang’s words were not merely arrogant; they bordered on outright audacity.

Not only did Mo Xiaotian find it hard to believe, but even Zhu Maotao was taken aback.

Mo Xiaotian did not take offense; instead, he smiled and said, “Oh, Section Chief Zhao, please do enlighten us. I, Mo, am all ears.”

Zhao Guoyang gave a short “hmm” and pointed plainly at the book, saying without hesitation, “First of all, sharing this question with Researcher Zhao was quite inappropriate.”

“As your senior, you should know she’s only a first-year graduate student. Her knowledge of vehicle performance is limited, and her thinking is rather constrained. Asking her to tackle such a challenging problem is asking too much.”

After Zhao Guoyang finished speaking, Zhao Siyan looked at her teacher Zhu Maotao in surprise.

In fact, when Mo Xiaotian initially shared the question with Zhao Siyan, Zhu Maotao had expressed similar reservations.

However, due to Zhao Siyan’s proactive insistence, he reluctantly agreed.

But Professor Zhu had also warned that Zhao Siyan should only try to conceive some ideas and not delve too deeply, fearing she might become stuck in a dead-end.

Zhao Guoyang, unaware of the exchange between Zhao Siyan and Professor Zhu, continued confidently: “Brother Mo, your project is essentially an offshoot of ‘NVH’—Noise, Vibration, and Harshness—set within the specific context of comparing the Beijing Jeep and the Songjiang Santana.”

“NVH?” Mo Xiaotian looked at Zhao Guoyang blankly, as if he had never heard the term before.

Jiang Hong, Liu Renhe, and Liu Yaohong exchanged glances, equally confused.

Only Wang Ziqing and Zhu Maotao looked at Zhao Guoyang with sharp interest.

Especially Zhu Maotao, who stared at Zhao Guoyang as if he had discovered a new world, eyes wide and unblinking.

Seeing the bewilderment on Mo Xiaotian’s face, Zhao Guoyang paused briefly and then realized: the term “NVH” had only started spreading from Western countries in the late 1980s and was not yet popular domestically.

It was no surprise that Mo Xiaotian was unfamiliar with it.

“The term NVH stands for Noise, Vibration, and Harshness,” Zhao Guoyang explained calmly. “It is a comprehensive measure of automotive manufacturing quality, giving the user’s experience in the most direct and superficial way.”

“By current trends, NVH issues have become a major concern among the world’s leading automotive manufacturers and parts suppliers. In the future, as people’s demands for vehicle comfort increase, its importance will only grow.”

Zhao Guoyang spoke fluently, as if transported back to the days when he addressed major conferences.

“You must be aware, Researcher Mo, that a vehicle’s performance is typically measured by various data indicators. For example, power is evaluated by top speed, acceleration, and maximum climb angle; economy by fuel consumption per 100 kilometers and maintenance costs. But how do you measure comfort?”

Noticing Mo Xiaotian’s astonished expression, Zhao Guoyang smiled and continued: “From the NVH perspective, as long as the noise, vibration, and impact experienced by occupants during driving stay within certain limits, comfort is deemed acceptable. Hence, comfort is primarily evaluated by the subjective feelings of the passengers.”

“But here lies the problem. Because each person’s psychological and physical sensitivities differ greatly, their sensitivity to NVH varies significantly.”

“This is much like aesthetics: opinions differ widely. Sometimes, what you consider an ‘okay’ car exterior might not appeal to someone else at all.”

“Beyond individual sensitivity differences, we must also consider the nature of different vehicle types. For example, a sports car must have the roar of the engine to convey a sense of control; while an off-road vehicle is favored for its strong impact sensations.”

“So, NVH requirements vary by vehicle type, which presents challenges during the initial design phase.”

At this point, everyone listened intently, barely breathing, afraid to miss any of this captivating explanation.

Even Zhao Siyan, who had long held a grudge against him, supported her chin with both hands and stared at him with wide, glistening eyes without blinking.

Zhao Guoyang took a sip from his thermos, cleared his throat, and continued: “Take this defense question as an example. It asks you to analyze the performance differences between the Beijing Jeep and the Songjiang Santana.”

“You built this simulation optimization model to compare their climbing ability, speed, and comfort. There’s nothing wrong with that. But is it comprehensive and objective? That is another matter.”

“For instance, the Beijing Jeep’s comfort on flat highways and expressways cannot compare to the Santana’s. But if you take it to the Gobi Desert, sandy beaches, or muddy terrain, it definitely has the edge.”

“In this regard, the two vehicles are simply incomparable! So what meaning does your simulation model have?”

Tapping lightly on the table, Zhao Guoyang said, “In fact, simulation optimization is indispensable during vehicle development. To some extent, it can greatly reduce the development cycle.”

“Take ordinary structural strength optimization as an example. If simulation shows a weakness somewhere, we can immediately consider changing materials, adding reinforcements, or optimizing the structure. This approach effectively and accurately improves the body structure, and simulations match real-world tests quite well.”

“But regarding NVH, despite numerous simulation methods, vibration tests, and whole-vehicle vibration experiments, it is still impossible to obtain precise, objective conclusions.”

“Most of the time, simulation results differ greatly from actual measurements, making it difficult to reduce costs and production cycles effectively.”

“Therefore, in my opinion, your project has been headed in the wrong direction from the very beginning!”

Zhao Guoyang’s final words struck like thunder, shaking everyone present.

Zhu Maotao restrained his excitement and asked carefully, “Xiao Zhao, if it were you defending this project, how would you approach it?”

Zhao Guoyang had been speaking with great enthusiasm, unaware of the reactions around him. Hearing Professor Zhu’s question, he naturally did not slack off, promptly standing to share his thoughts.

“Professor Zhu, if I were to tackle this project, I wouldn’t focus on building simulations or control systems. Instead, I would concentrate on the after-sales service of the Songjiang Santana and Beijing Jeep.”

“First, I would gather common feedback issues from the after-sales reports of both vehicles. Then, based on the solutions to these problems, I would create a comparative data table.”

“This table would include both vertical and horizontal comparisons. The vertical comparison tracks the same vehicle’s feedback before and after problem resolution; the horizontal comparison contrasts how similar issues are handled between the two models.”

Zhao Guoyang concluded, “Once these comparisons are made, the difficult question posed by you, Professor Zhu, would basically be resolved.”