I don't know if you have noticed a phenomenon, when you go to the store to look at cars, many users are even more professional than salespeople. The professional terms such as silicon carbide, 5C charging, L113, end-to-end, and AI big model are all very clear.
Whether the sales pressure is significant or not, it is inevitable that car companies will spend more time on promotion. After all, everyone has tried it before, and if you want to make someone exclaim 'NB', you have to bring something real out.
Especially in the past two years, with such fierce competition, car companies have been thinking about showcasing their muscles in a French way. Tesla has AI Day, Xiaopeng has 1024 Technology Days, NIO has NIO IN Technology Day, and Guangzhou Automobile Group, SAIC Motor, and Dongfeng Motor also have their own Technology Days.
So that the ideal of ranking first among the new forces in sales has been roast by everyone that "there is no unique skill":
But in reality, the ideal is not completely devoid of core technology, it just adds skill points to details such as cockpit interaction, PQ perception quality, end-to-end+visual language model, and even wind resistance coefficient.
Taking NVH as an example, in @ Dr. Zheng Barton's dynamic NVH test, the performance of the Ideal MEGA and L series ranked among the top few on the list. Not only does it outperform a luxury car, but it is also much stronger than the Ideal ONE a few years ago.
If we only look at it from this perspective, the ideal can really be called 'the best within 5 million'.
So, what does NVH really mean? Is it what people call mysticism? How should we optimize it?
Today, let's have a good talk about NVH.
01. Is NVH mysticism?
Whether it's at car companies' press conferences, offline sales introductions, or online discussions, the frequency of the letters NVH is not low. But correspondingly, NVH is almost never the protagonist every time it appears.
For a car, people are more concerned about its range, energy consumption, space performance, comfort, and performance. If NVH happens to be mentioned, just take a look by the way; If it's not mentioned, I won't deliberately study it.
After all, the most widely spread statement about NVH is' NVH is mysticism '!
Indeed, NVH, as a shorthand for Noise, Vibration, and Harshness, is a comprehensive perception that carries a great deal of subjectivity when evaluated.
Noise and vibration, everyone knows what they mean.
But even with the same sound, everyone will have different feelings because different people's ears can receive different frequencies and hear different levels of loudness (which affects hearing, that is, deafness).
Taking the president himself as an example, he couldn't accept the resonance of the tailgate of a friend's car at all. He felt deafening just a little faster. But the friend himself appeared completely indifferent, indicating that human joys and sorrows are not interconnected.
Vibration is the same. Some people feel uncomfortable walking on gravel roads, while others think it's not as strong as using a seat for massage; Some people think that seat massage (a slow paced vibration) is very comfortable, while others feel that it is not exciting at all
Not to mention the "mysterious yet mysterious" roughness of sound and vibration - this is a purely subjective feeling used to describe how uncomfortable people feel when noise and vibration change.
For example, when the range extender works desperately in a low power state, it is much more unpleasant than when it is not low on power.
Because NVH is so difficult to tune, almost one-third of faults are related to the vehicle's NVH; Car companies also need to allocate nearly 20% of their research and development expenses to solve the NVH problem of vehicles.
But! This NVH is not really mysticism, but true science.
Physics still exists, and the decibel level of noise is objective. If it is high, it will be noisy, and if it is low, it will be quiet; Whether the range extender shakes or the chassis shakes is also objective data that can be measured.
This also means that NVH can be optimized through data quantification and subjective evaluation by NVH engineers.
So, how can we improve NVH performance? To be honest, it's a bit difficult.
Because NVH is not something that can be solved by a single department, but requires collaborative system engineering.
For example, reducing the wind noise of a vehicle is not just about optimizing the body shape or replacing the double-layer laminated glass. It is also very important to ensure sufficient adhesion between the glass and the car body, as well as between the metal surfaces of the car body.
To reduce gaps, it involves issues of body structure design and manufacturing processes... like dominoes, one pull can move the whole body.
Even if all the above chains are run through, it will be found that the effort has been wasted for a long time, and in the end, it is only reduced by one or two decibels. But the manpower and material resources expended are not insignificant.
Tens of thousands of components in cars, over 30% of which are related to NVH!
So when it comes to overall accounting, optimizing NVH is a bit like an investment that doesn't pay off, with little return but significant investment.
Unless pursuing the ultimate, blindly pursuing NVH is not in line with the thinking of engineers. After all, there is no end to the car, and trade-offs must be made under limited costs, and NVH is the one that is prioritized after performance, space, and comfort.
Therefore, for a long time, it was luxury brands that could sell at a high premium that pursued NVH, which indeed brought a driving quality stronger than ordinary brands.
As the founder of Ogilvy Advertising wrote for Rolls Royce in 1959, "At 60 miles per hour, the biggest noise inside this latest Rolls Royce comes from its electronic watch
02. In the era of new energy, has NVH changed?
This situation has undergone significant changes in the era of new energy vehicles.
The addition of electric motors has made the engine and gearbox a complete burden. For the vast majority of household cars, people will no longer hear the continuously increasing roar as they step on the accelerator, let alone the annoying loud noise during rapid acceleration.
Even if the fuel tank must be kept, the engine appears most of the time as a range extender, searching for its most comfortable RPM, like a quiet 'handsome man'.
In contrast, the noise of the motor is high-frequency noise, which does not produce uncomfortable low-frequency resonance and has lower decibels than engine noise, which means that new energy has a natural advantage in NVH.
But this advantage doesn't seem absolute either.
For example, a Tesla Model 3 owner in the United States conducted a test: on the same interstate highway, a Tesla driving at a constant speed of 70 miles per hour had a noise level of 74 decibels; And his Lexus ES350 only has 67 decibels!
This pot is not backed by new energy.
The sources of noise are not only the engine and motor, but also road noise from tires and the ground, wind noise between the air and the body, and even interior noise from seat ventilation fans/seat massage motors, air conditioning vents, and so on.
Although the engine no longer exists, other noises inside the car have not disappeared. Even without the "cover" of the engine, these noises become more obvious and difficult to accept, which actually disrupts the balance of the overall sound of the vehicle.
To some extent, the excellent innate conditions of electric vehicles are both a blessing and a curse. It has put forward higher requirements for the quietness of vehicles, forcing OEMs to optimize the overall noise situation of the vehicle.
This also means that car companies need to spend more money on NVH optimization.
But compared to the engineering mindset that prioritizes cost and functionality, product thinking is different.
The logic of product thinking is that everything starts from user experience, and the product is optimized based on what users perceive. As long as users really need to optimize NVH and distinguish themselves from other car models, then this money is worth it!
This kind of user thinking is the reason why car companies want to vigorously promote NVH.
03. How to optimize NVH?
Li Xiang, the strongest product manager in the automotive industry, is not just a name for himself. The refrigerator, TV, and sofa have indeed improved comfort and usability, and have received unanimous praise from everyone when placed in any car.
You should know that this' new three electricity 'is not a groundbreaking technology. But before, there were no car companies or models willing to delegate these to household users, instead allowing them to serve as a "watershed" between flagship products and ordinary products.
NVH， It was also for this reason that Li Xiang fiercely caught him.
In the development process of the Ideal L9, they proposed that the NVH of L9 should be benchmarked against BMW X7, and that "the NVH index of L9 should comprehensively exceed that of X7, not just meet the 85% level".
To this end, the Ideal L9 has installed resonance blocks on the upper fork arms, protective plates below the chassis threshold, and uneven thickness wheel covers to reduce noise from the chassis;
The refrigerant expansion valve in the thermal management system has also been optimized, even if it will increase the cost by 140 yuan per vehicle.
In an ideal world, optimizing the slight hiss sound emitted by the air conditioner means making the noise go from audible to inaudible, and the money is well spent.
In terms of vibration, in addition to jointly developing and tuning with range extender supplier Xinchen Power (authorized by BMW technology), over 90% of ideal models are equipped with air suspension and self-developed "magic carpet system", which can filter out most of the fine vibrations in comfort mode.
At MEGA, the ideal was further developed by collaborating with suppliers for better NVH performance.
A typical example is the solution proposed by the Ideal NVH team to transform the fan blades into nine biomimetic wavy blades in response to the fan noise emitted by the thermal management system.
In addition, with multiple optimizations at the vehicle level such as vibration absorption on the seat frame and the use of acoustic laminated glass as the third row windows, the NVH performance of the Ideal MEGA has been further improved, finally reaching the level of many million dollar luxury cars.
From this, it can be seen that optimizing NVH is not just about "stuffing some sound insulation cotton" as many netizens say. It requires a certain level of technical strength, and more importantly, car companies need to come up with "real money and silver".
04. Write at the end
I believe everyone can feel the texture represented by NVH.
But the most unpleasant thing is not that the car is particularly noisy (Ferrari should be loved by many people even if it is noisy), but rather the inexplicable noise.
Even a million dollar luxury car, after driving tens of thousands of kilometers on bumpy roads such as gravel roads and speed bumps, is inevitably prone to interior noise, with various causes——
When you notice that there are large gaps in the interior, loose decorative panels, or aging sealing strips... in short, it is difficult to ignore them, and for people with OCD, it is as uncomfortable as scratching their hearts with a hundred claws.
This also makes many people start to doubt themselves: I spent so much money on buying a car, why is it so bad?
In recent years, our automotive market has developed rapidly, and car companies are also growing together with users.
20 years ago, most users' wish was just to buy an entry-level car that could provide shelter from wind and rain;
Ten years ago, the wish of most users was to buy a family car that was easier to drive and had more space;
Nowadays, user demands are becoming increasingly diverse and demanding. Our Chinese brands should also keep up with this development and satisfy users with more details.
Previously, Chinese brands may not have the energy and financial resources, let alone the ability to value NVH. But now, as cars are no longer luxury items for ordinary Chinese families, these details will gradually become familiar to users.
Car companies that are not yet ready to get involved in details and technology need to tighten their grip!