What are the stuck links in domestic engine manufacturing?

Stuck in the neck means that there are areas and products that are obviously monopolized by foreign companies.

Simply put, there are 3 extremes, basic materials, system applications and industrial software. As for independent hardware components, China’s purely local enterprises can already do well. It is common for joint ventures to use Chinese factories as global benchmark factories for manufacturing. Many Chinese local brand OEMs also have many names of their own micron factories. Gone are the days when local companies in the 2010s bought third-hand production lines from South Korea.

Let’s take a few examples:

Basic Materials:

When carrying out some coating processes, especially those related to physical vapor deposition (PVD), some ultra-pure metal materials are required, all of which need to be imported from Europe.

The valve spring of the engine, from wire drawing to spring manufacturing, has already been localized. However, the steel used in valve springs, from China’s joint venture car companies to the most cost-effective independent companies, no Chinese car company dares to use domestic materials. The reason is that the characteristics of the valve spring require ultra-pure steel, and the control of the poor structure of the steel is less than 1% or even less than one thousandth of the normal spring steel. China’s steel mills have been working on engine valve spring steel since the 1980s. More than 40 years have passed, and many samples have been made, but none of them have been successful. In this regard, some of my colleagues and I are currently working on development projects with Nanjing Iron and Steel, providing confirmation of benchmarking and development certification, as well as third-party material analysis and comparison and engine simulation support to help Chinese steel mills achieve this. We have been working alone for more than 4 years, which is our contribution to China’s steel industry.

The purpose of doing this is not only to make valve springs, but because spring steel is the pearl of special steel technology, and engine valve spring steel is the pearl of the pearl. This means that this steel mill has mastered the ability to smelt special steel with ultra-high strength, ultra-purity, and ultra-stable stability, and can guarantee stability in batches. This is strategic work.

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Iron powder used in powder metallurgy and powder metallurgy forging techniques.

Powder metallurgy is a very common technology. Many high-tech machinery companies are doing it, and there are also many small workshops doing it. The traditional process itself is relatively simple, and it is good to sinter after pressing. The key here is the iron powder. The more technically demanding parts are, the more powder imported from overseas is needed, mainly from U.S. factories such as GKN. The reason why high-end powders rely on imports lies in the complexity of their manufacturing methods.

The approximate technical model is that molten high-purity molten iron is poured down from a high place in a furnace. The whole furnace is partially vacuumed with inert gas, and then the molten iron is blown up with inert gas under controlled conditions. Then the molten iron is blown and broken into regular and rounded small particles and cooled.

Most of the domestic powder adopts physical pulverization method or chemical method, which is far inferior to the large-scale atomization method abroad in the field of high-quality performance requirements.

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Powder metallurgy forging is a more special technology. Traditional powder metallurgy sintering is just fine. Powder metallurgy forging is further forging on the basis of sintered powder metallurgy. There are many special processes for the mold and subsequent sintering.

But the core of powder metallurgy forging technology is not only the process, but also the material development based on these processes. At present, the tensile strength of the best forged steel materials for engines is about 1150MPa, and the best new powder metallurgy forging materials in the United States can achieve a tensile strength of 1950MPa. And it can also achieve that the hardness is not too high, and it can achieve that the hardness is not too high. Controlling hardness is beneficial for tool protection during large-scale machining. This material is currently used in the United States in military and high-end auto parts, and may be embargoed to China. At present, the tensile strength of 1250MPa can be achieved for domestic use. Those who study the material know what they know. The first time I saw the 1950MPa material, I thought they spelled it wrong. until I actually saw the material.

The reason why they are incompetent in material development in the short term is that these companies have invested a lot in the basis of materials, and they have continued to invest for a long time. For example, for many materials, the domestic mechanical properties are basically finished at room temperature. An American powder metallurgy material company has made hundreds of different materials and powder metallurgy materials with different formulations from low temperature to high temperature. Then more than a dozen new materials are made every year.

Absolute monopoly of non-metallic materials:

The more high-end plastic granule formulations are, the more absolutely monopolized by foreign companies. Many so-called plastic formula companies in China are also porters of plastic formula;

We all know that there is a thing called GPF in China VI emission. At present, there are some domestic companies doing this thing, which is also a very remarkable thing. But there is basically only one company with the GPF carrier (before coating) in it. This company is well known by girls and is called Corning. As my country’s emission regulations are typically ahead of the National VI, the progress is too fast, and the intake and exhaust and after-treatment are the hardest hit areas that are monopolized by overseas materials and key structural designs. And it should be unresolved for a long time.

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Monopoly of engine oil additives:

As we all know about engine oil, many people also use engine oil brands provided by domestic enterprise groups such as PetroChina and Sinopec, and they are also good. But the oil is mainly divided into two parts, 1 is the base oil, 2 is the additive. The main profit is in the additive segment. At present, there are many base oils in China, but the research and development of engine oil additives is mainly carried out by foreign companies, such as Idemitsu, Afton, Lubrizol, Infineum, Castrol and so on.

system application

Here mainly refers to the electronic control and fuel injection system. The domestic substitution of diesel engines is relatively good, mainly due to a long period of development. The progress of my country’s diesel technology regulations is about 5-6 years slower than that in Europe, and there is a relatively long time for domestic development in China. . On the other hand, it is also because my country has not taken the road of high-speed diesel engines for vehicles in Europe, and the complexity of the control strategy of diesel engines in the field of commercial vehicles and the processing accuracy requirements of related parts are still weaker.

In fact, there are already many companies that can make injectors, wiring harnesses, and some electronically controlled sensors and accessories, including direct matching as aftermarket parts in the market. However, because there are still a few main developers of electronic control systems: UMC (Bosch), Delphi, Denso, etc., they generally only use their own supporting parts to make the system.

It is not that there is no domestic electronic control system in China. For example, Qinchuan Flair Automobile, which was later acquired by BYD in Shaanxi, once developed its own EFI system, and my graduate tutor was also responsible for the development of the core parts. Later, a part of the system was transplanted into the engine control system of a famous Chinese unmanned aerial vehicle (my graduate students are still traveling between the Qinling Mountains and Egypt and other countries)…

Another example is the methanol vehicles that Geely Automobile participated in national pilot projects in Gansu and other provinces. UMC refused the development task because there were too few methanol vehicles. Therefore, Geely Automobile developed a domestic electronically controlled injection system service provider, and then supported it all the way to the present. The data is said to be good.

However, as far as the traditional fuel field is concerned, these traditional suppliers are the most powerful. Moreover, due to the increasing requirements for electrified components and intelligent control in recent years, the development of control systems and calibration strategies has begun to shift to a virtual development model, and this distance will actually increase in the future. Moreover, the current uncertainty about the future of domestic fuel vehicle development policies has seriously affected the investment in this type of technology. Therefore, there will basically be no new catching-up enterprises in China in the future. However, if fuel vehicles are maintained because of alternative fuels, the follow-up gap will become larger and larger, because every time a domestic car company develops an engine, the other party accumulates a massive wave of data and models. With the current machine learning and virtual With the development of iterative development, there are better methods for the refinement of these model data and automatic learning iteration, so this kind of iterative experience will become more and more.

Industrial software

This is probably the weakest. Not to mention independent design and simulation software such as 3D modeling, calculation software, calibration software, NVH test software, structural simulation, fluid simulation, combustion simulation, vibration and noise simulation, temperature field simulation, etc., the future development path is more in-depth Design modeling and integration of CAD and CAE. You can understand that when you want to design something in the future, you can directly modify a few parameters, and the model will automatically start to build and consider process constraints such as minimum wall thickness and minimum chamfer, and then automatically check the space interference constraints to make avoid. After the design is completed, the simulation will automatically follow the simulation results. Where the safety factor is high, the meat will be automatically reduced, and where the safety factor is insufficient, the most reasonable part will be found to add meat according to the sensitivity.

The future industrial design will become simpler and simpler, but there are a large number of algorithm models behind it, and many simulation-related algorithm models are based on monitoring the high-precision real-time measurement values ​​of a large number of actually running parts, comparing them with the model simulation results, and then correcting the model. Finally, the model has the response characteristics of the real system. This is the so-called digital twin in the true sense.

Now many countries, especially the United States, are trying to build an “absolute advantage model” in various fields, even in the field of mechanical design, which we traditionally think is purely human labor. In the past few years, I gradually began to notice that many American suppliers and American research institutions that I cooperated with sent me design prototypes, and the structure became more and more beautiful. The so-called beauty means that the lines of the model are getting smoother and smoother, and more and more smooth surfaces appear. It has reached a state of elegance and beauty.

This made me panic, and sometimes even Ding Yi felt like when he saw water droplets. Because people who have really done structural design will know that when your design has to meet many process requirements, clamping positioning and interface requirements, it is difficult to appear smooth curves and surfaces, especially some must be designed first, and then Calculate, and then add meat or reduce meat at a specific position, and then meet the requirements. Even if you add the default round transition at the end, there must be a connection between multiple curves and surfaces in the model.

My vivid description is that when a normal person draws something, the normal thing is to first draw the basic structure, then gradually enrich and adjust it, and finally adjust to a suitable design.

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And I see it all the time now, and it feels like a one-off design. I feel that when a painter makes his first stroke, he already knows the whole Mona Lisa. In other words, an artist starts drawing the first hair, and immediately starts painting, because at this time he already knows where to draw from the position of the remaining hair on the head to the shoelaces on the feet.

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In fact, the industry has been calling the industry 4.0 wolf for many years. Many people think it is a gimmick. I once thought so, but in the past four years, I feel less and less, and I am also leading the way in this area. Work on the base model. These are not only on the design side. In the future, such models can be directly placed in the intelligent machining center. The machining center automatically allocates the processing volume of multi-tools and the clamping and processing points according to the difference between the blank model and the machined finished model. Step details, and then automatically compile the sub-process diagram and processing parameters.

In the future, you will find that you must buy a certain software to reduce design errors, you must order a certain software library to allow your engineers to complete the design, and you must purchase a complete set of machining centers from a certain company. In the case of manufacturing specialists, temporary workers recruited for very low salaries can complete complex parts manufacturing work.

The fundamental material science and model-based design revolution is what we should be most worried about getting stuck.


Many people actually think that since the internal combustion engine is so troublesome, wouldn’t it be better to just bypass it and not do it. But in fact, you will find that the engine has such a large inventory and tolerance of such a large manufacturing cost, which is precisely the basic platform to support advanced materials and advanced manufacturing applications. Because in modern industry, you must have enough manufacturing volume to support your development of materials, processes, designs, and software systems.

The car engine is actually equivalent to setting up an offline power station in the front cabin of each car. It is possible to extract ordered and high-quality mechanical energy from the lowest quality disordered combustion thermal energy in each vehicle, and the efficiency is not bad, and the cost can support popularization and most people can accept it. This is nothing short of an industrial miracle. Supporting this miracle itself is the iterative breakthrough of a large number of materials, processes, structures and design capabilities over the past century. You think you have bypassed this pit, but in fact, not to mention that you cannot bypass it at all, what I want to say is that the basic science behind it will silently wait for you to hit it on another track.

Source: Zhihu www.zhihu.com

Author: JackyQ

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Further reading:

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