Many friends know that the engine oil needs to be changed when the vehicle is maintained, but many people don’t know what the function of engine oil is and how to choose engine oil. Today, Xiao Jia will introduce you to the knowledge about engine oil!

Automobile lubricating oil can be generally divided into three types because of its different functions: engine oil, gearbox and differential oil, and grease (butter). The most common thing in vehicle maintenance is to change the engine oil.

Engine oil has five functions.

Lubrication function: the function of engine oil is to fill and lubricate the surfaces of moving parts and reduce the friction between moving parts. Its working principle is: the engine oil is pressurized by the oil pump and transported between the rotating parts, and an oil film is formed on the two friction surfaces to separate them, thus reducing the contact surface between moving parts, thus reducing wear and prolonging the service life of parts. There is surface friction between piston and cylinder, crank-connecting rod mechanism, cam valve train, gear rotating mechanism, etc., which must be lubricated by engine oil to ensure normal working conditions.

Cooling function: engine oil can bring back part of the heat generated between the rotating parts of the engine to the oil pan, and achieve the cooling effect through the oil pan wall. Some engines are also equipped with special engine oil radiators to achieve better cooling effect, so as to ensure the normal temperature between the rotating parts of the engine and keep the engine in normal working condition for a long time.

Sealing function: The engine oil also has a sealing function. For example, the engine piston ring and the cylinder wall are filled with engine oil, so that the contact surface and the gap have both a lubricating function and a sealing function, so that the piston can reduce air leakage when inhaling and compressing, and ensure the normal working compression ratio. If the piston ring and cylinder wall are worn, the sealing effect of engine oil can be improved by adjusting the viscosity of engine oil or adding engine oil additives, thus improving the working condition of the engine.

Cleaning function: The engine oil is pressurized by the oil pump and transported between the rotating parts of various parts for lubrication and heat dissipation. At the same time, it can also wash and clean the rotating working surface of the parts, bring the dust particles entering the engine and the garbage generated by the work to the oil pan, and keep the engine parts, rotating working surface and oil passage clean and smooth through the oil collection net and oil filter, thus ensuring the normal operation of the engine.

Rust-proof function: The working environment of the engine is complicated, and the climate change in spring, summer, autumn and winter will easily cause the metal parts to rust and deform, which will affect the normal operation of the engine and shorten its service life. The oil is pressurized by the oil pump and supplied to all parts and metal surfaces through the oil passage to form an oil film to isolate the air, which can prevent the metal surface from oxidation and rust and improve the service life of the engine.

If the engine is likened to the heart of a car, then the engine oil is the blood of the engine, which is a necessary condition to ensure the normal operation of the engine. Understanding the knowledge of engine oil, correctly selecting and using engine oil, and regularly replacing and maintaining it are very important to ensure the normal operation of the engine and prolong its service life.

More car maintenance tips

Please pay attention to Monday to Friday at 17:00.

Jiading China National Radio

FM 100.3 MHz "Where to Go After Work" program

Written by Yang Chen, video.

Editor: Wang Lihui, Wu Lirong

[car home Dalian Preferential Promotion Channel] Recently, preferential promotion activities are being carried out in Dalian, with a maximum preferential amount of 20,000 yuan and a minimum starting price of only 159,900 yuan. In order to get more discounts, please click "Check the car price" in the quotation form.

Magotan’s exterior design is full of modernity and dynamic, and the front face design is simple and atmospheric, and the family-style air intake grille design is adopted, showing a dynamic visual effect. The overall style tends to be steady and exquisite, and the body lines are smooth, creating a strong sense of movement. Magotan can show its unique charm in both business occasions and daily travel.

Magotan’s body size is 4866*1832*1479 mm, and the wheelbase is 2871 mm, providing passengers with spacious and comfortable seating space. Its side lines are smooth and dynamic, with a front track of 1584 mm and a rear track of 1570 mm, which enhances the stability and handling of the vehicle. Magotan is equipped with 215/55 R17 tires. With the fashionable rim design, it not only improves the visual effect of the vehicle, but also ensures excellent grip and driving stability.

Magotan’s interior design is simple and exquisite, and the center console adopts a well-defined layout, with an 8-inch or 9.2-inch central control screen, creating a full-fledged atmosphere for the car. The steering wheel is made of genuine leather, which feels comfortable and supports manual adjustment up and down and back and forth, ensuring the driver’s comfort and convenience. The car is equipped with rich multimedia and charging interfaces, including USB and Type-C interfaces, which meet the needs of daily use. In addition, Magotan is also equipped with wireless charging function of the front mobile phone, which greatly facilitates the driver. The seat is made of high-quality imitation leather, and the main and auxiliary seats have the functions of front and rear adjustment, backrest adjustment and height adjustment, which improves the riding comfort. The rear seats can be laid down in proportion, providing more space for storage.

Magotan is equipped with a 1.4T 150 HP L4 engine with a maximum power of 110kW and a maximum torque of 250N·m, which is matched with a 7-speed dry dual-clutch gearbox and has excellent power performance.

The owner of car home said that Magotan’s exterior design is calm and atmospheric, and the raindrop intake grille makes him feel young and dynamic, while the horizontal chrome-plated strip adds the atmosphere of business and gentleman. The waistline design makes the car look slender, the duckling tail design at the rear is sexy and plump, and the design of four exhaust pipes is sporty and publicity, which shows the extraordinary charm of Magotan.

????On April 20, 1994, China realized full-function connection with the Internet, thus opening the Internet era. These Internet-related pictures, no matter big or small, make us feel that the Internet has profoundly changed the lives of China people in the past 20 years.

????In 1996, a round of home computer craze rose in Shanghai. According to the survey at that time, the penetration rate of home computers in the city reached 5‰, 486 microcomputers were common, 586 microcomputers began to enter families, and a few families were connected to the Internet. Zhang Jianmin (left) is the general representative of a foreign company in Shanghai. His personal computer is connected to the international network. Every day after work, he sits at home and keeps in touch with foreign companies quickly and conveniently (photo taken in 1996).Xinhua News Agency reporter Zhang Mingshe

????During the "May 1" holiday, netizens surfed the Internet in Chongqing Reader Club (photo taken in May 2001). Xinhua News Agency reporter Zhou Hengyi photo

????On April 17th, 2004, a player in Beijing Division of China E-sports Games waved excitedly to the audience after scoring a goal in the FIFA football match. On the same day, the first China E-sports Games (CEG for short) was held simultaneously in Beijing, Changsha, Wuhan and Xi ‘an. Xinhua news agency

????On April 11th, 2006, the staff of Baidu Company introduced the signature wall of Baidu employees. In August, 2005, Baidu went public on NASDAQ, setting a record of the highest increase in the IPO of NASDAQ in the five years since the Internet bubble in 2000. Xinhua News Agency reporter Li Shilei photo

　　Who is responsible for the traffic accident on the way to work? Similar problems still plague many "riders". Recently, Beijing Tongcheng Bing Technology Co., Ltd. lost a lawsuit in a motor vehicle traffic accident liability dispute trial, which caused more than 20,000 yuan to the plaintiff in traffic accident compensation, and was also recognized as "having a labor relationship with the courier". However, in the cooperation agreement signed between the courier and the company, Tongcheng Bing Company still defines the business model of "platform+individual" as "business cooperation relationship", which is not adjusted by labor laws and regulations. To this end, many couriers have questioned whether such a cooperation agreement is reasonable and legal.

　

　　◎ Text/Figure Shandong Business Daily Su Bao News Network reporter Sun Wei Li Yuxin

　

　

A courier on the streets of Jinan

　

　　After the flash was awarded more than 20 thousand yuan, the plaintiff dropped the lawsuit

　

　　A few days ago, a civil judgment issued by the Dongcheng District People’s Court in Beijing showed that on March 25, 2021, a traffic accident occurred between the citizen He Mou and the flash driver Li Mou, causing the plaintiff He Mou to be injured and the contact part of the vehicle damaged. The traffic management department determined that Li, the flasher, was fully responsible for the accident, and He sued Beijing Tongcheng Bing Technology Co., Ltd., the company to which the flasher belongs, for compensation.

　　In this regard, the same city Bing Company argued that there was no employment relationship with the flasher Li. However, after the court heard the case, it was determined that the company had an employment relationship with the courier Li, and the same city Bing was sentenced to pay He 20,770 yuan.

　　However, Bing Company in the same city appealed the verdict again last month. According to the judgment document of the second instance published on March 8, after the appeal of the same city Bing Company, the plaintiff He Mou applied to the court to withdraw the prosecution. As for the reasons for withdrawing the lawsuit, the reporter sent a letter to consult the Flash Brand Department, but as of press time, he did not receive a reply.

　

　　Flash delivery has been listed as the person subjected to execution for many times due to accident disputes.

　

　　The reporter found out that this kind of traffic accident liability dispute has become the main legal risk of Bing Company in the same city. Sky Eye Survey shows that the top three cases in the company are motor vehicle traffic accident liability disputes (95 cases), labor disputes (37 cases), and disputes over life, health and body rights (31 cases). In the first three months of this year alone, there were 19 court announcements or civil judgments issued by Tongcheng Bing Company.

　　It is noteworthy that Tongcheng Bing was listed as the executor by the local court several times. Eye-catching investigation shows that Beijing Tongcheng Bing Technology Co., Ltd. was enforced by the court seven times for failing to fulfill its legal obligations on time, at least four of which involved traffic accident liability disputes of flashers.

　　In August last year, the flasher Jiao Mou collided with the plaintiff, and the same city Bing Company proposed to recognize Jiao Mou’s accident in the process of sending "flashover" and agreed to bear the losses within a reasonable range of the plaintiff. The Chaoyang District People’s Court of Beijing ruled that Jiao and Bing Company in the same city jointly bear more than 5,000 yuan in compensation. However, on December 13, 2021, Tongcheng Bing Company and Jiao Mou failed to fulfill their legal obligations and were listed as executors with an execution target of 5,304 yuan.

　

　　Regarding the determination of the labor relationship of the "flash worker", Flash once replied to our reporter in September 2020 that the legal relationship between the flash worker and the platform is still inconclusive at the legal level, and the current effective judgments all determine that there is no labor relationship. However, after a year and a half, now looking at the trend of court decisions, it seems that the company can no longer easily "throw the pot".

　

　　Cooperation agreement can not avoid the identification of labor relations.

　

　　The reporter learned from the mouth of the courier that the basis for the "throwing pot" of the courier comes from the "Cooperation Agreement" signed between the courier and the platform. The agreement stipulates that the platform and the courier establish a business cooperation relationship, and there is no labor relationship between the employer and the laborer, which is not adjusted by labor laws and regulations.　　　

　　In this regard, many flashers openly questioned on the platforms such as Post Bar and Zhihu, emphasizing that the company needs to purchase specified equipment for single quantity assessment, which obviously goes beyond the so-called "cooperative relationship".

　　Is such a "cooperation agreement" reasonable and legal? Ma Sicheng, a lawyer of Shanghai Duanhe Duan (Jinan) Law Firm, said: The cooperation agreement does not conform to the provisions of the labor law. Now the legal judgment on such issues is in a transitional period and cannot be treated with a fixed eye. However, common problems such as injuries caused by riders, whether it is labor relations or labour relation, should be borne by the platform. At present, the people’s courts judge similar cases by using the legal provisions that laborers cause damage to people and providers cause damage to third parties.

　　At the National People’s Congress in 2022, Pi Jianlong, member of Chinese People’s Political Consultative Conference and director of Beijing Jintai Law Firm, pointed out in the proposal that the development of flexible employment and platform employment deformed the original "standard labor relations" and led to the establishment of multiple labor relations. In July, 2021, the Ministry of Human Resources and Social Security and other eight departments jointly issued the Guiding Opinions on Safeguarding the Labor Security Rights and Interests of Workers in New Employment Forms, but Pi Jianlong pointed out that the Guiding Opinions are policy norms and are not legally mandatory. It is necessary to further determine the protection of the rights and interests of workers in new formats in law and give them "strong protection" in the labor law.

　　Man made glass more than 5000 years ago. Archaeological evidence shows that in Egypt and Mesopotamia in 3000 BC, people have made some small handicrafts such as amulets and beads with glass.

　　By around 1500 BC, people’s skills in making glass were becoming more and more mature, and the first glass container appeared in human history. The ancient Egyptians also mastered the technology of coloring glass. They know that adding copper powder to glass can make red glass, adding cobalt powder can make blue glass, and adding tin powder can make white glass … These colored glasses are used by some unscrupulous businessmen to pretend to be jewelry, deceiving many people.

　　In the 1st century BC, Syrians invented the technology of blowing glass. With this technology, making glass becomes simple, fast and cheap. Since then, the glass industry has flourished in the Roman Empire and quickly spread to other countries under the rule of the Roman Empire.

　　Around the 1st century A.D., the Romans discovered that adding a proper amount of manganese dioxide to glass could make colorless glass, so they began to make windows out of glass and install them on buildings. Although the optical performance of glass at that time was very poor, glass windows were still "standard" for buildings in Rome, Pompeii and other places.

　　In the 8th century, Venice concentrated a large number of glass workers and became the glass manufacturing center at that time. Later, with the progress of science and art, people "played" more tricks, such as dyeing paint on glass and drawing colorful patterns. Many churches we see now have stained glass windows, which is the architectural style left over at that time.

　　In the mid-15th century, a glass worker in Venice invented a new type of super transparent glass. Soon, this new type of glass was used to make telescopes, thermometers, flasks, microscopes and other scientific instruments, which led to many important scientific discoveries.

　　Around the 18th century, the glass manufacturing center in Europe moved from Venice to Britain. At that time, the output of British glass factories was very high. At one time, the British government would levy taxes based on the number of windows in each house, on the grounds that wealthy families would install more windows, and of course they should pay more taxes. However, "there are policies above and countermeasures below", and many families simply blocked the windows in order to avoid paying taxes-this story shows that the use of glass was quite common in Britain at that time.

　　Since the industrial revolution, steel and glass have become important building materials for modern architecture. In 1851, Britain built a "Crystal Palace", which only used steel and glass. This miraculous building was also the exhibition hall of the first World Expo in London. In 1950s, a German architect innovatively covered the facade of the building with a layer of glass, which made the appearance of the building look unprecedented. This innovative design can be successful, on the one hand, because there is a reinforced frame inside the modern building, and the facade does not need to bear the weight of the whole building; On the other hand, because the strength of glass has become higher. So many skyscrapers we see now have glass facades.

　　Nowadays, scientists and engineers have developed a variety of glasses, which have important uses in many fields. For example, there is a kind of glass that can quickly transmit network information, that is, optical cable, which is filled with thousands of glasses as thin as hair, in which communication signals shuttle in the form of light and quickly transmit information to all parts of the world.

　　Sand and glass

　　The main component of glass is silica, that is, Shi Ying, which is one of the most common minerals on the earth. The sand that can be seen everywhere is actually a small particle in Shi Ying. When Shi Ying is heated to 1400℃, it will melt, then become soft and become a transparent, viscous liquid-then it will be cooled and shaped, and then the glass will be finished.

　　How did sand become glass?

　　On the atomic scale, silicon dioxide is composed of silicon atoms and oxygen atoms, and they are arranged in order in Shi Ying. For example, a group of silicon atoms and oxygen atoms are neatly arranged to form a "queue" with specific arrangement rules, and the whole "queue" is Shi Ying particles. A structure like this, which consists of a large number of microscopic substance units (such as atoms and ions) arranged in an orderly manner according to certain rules, is called a crystal.

　　After Shi Ying melted, its internal crystal structure was destroyed, or the original "queue" was disrupted, and silicon atoms and oxygen atoms began to "run" freely, making Shi Ying change from solid to liquid. Of course, if the liquid Shi Ying can be cooled quickly, the crystal structure will be re-formed, just like the silicon atoms and oxygen atoms that "run" at will "stand" in the original position in the queue again.

　　However, if the cooling speed is too fast, so that silicon atoms and oxygen atoms can’t return to their original positions, then they can only be condensed in their current positions. Therefore, the final glass is like a snapshot of liquid Shi Ying. Scientists have a special name for this state of solid, called "amorphous solid", which means that this kind of solid is different from crystal, and there is no orderly arrangement rule in its internal structure.

　　Why is glass transparent?

　　We can’t go straight through the glass, but our eyes can see the objects on the other side through the glass. Why?

　　We can see an object because the light is reflected or scattered after it reaches this object, which makes some light enter our eyes and let us see the shape and color of the object. Only a part of light energy is received by our eyes, and the rest is absorbed or intercepted by objects.

　　How much light an object can intercept depends on the kind of molecules or atoms that make it up.

　　Most of the atoms in the glass don’t intercept light, and almost all the light that reaches the glass can be received by the eyes (glass can intercept ultraviolet light, but our eyes can’t see ultraviolet light). In addition, glass is not crystal, and there is no edge edge edge of crystal structure inside, so it will not scatter light. So, when the light reaches the glass, it will go straight through without changing its direction.

　　However, if a piece of glass is slightly thicker in some places, the propagation path of light will be bent, which is the working principle of a prism.

This article is from Science Illustrated.

[car home Weifang Preferential Promotion Channel] At present, preferential promotion activities are being carried out in Weifang market, with the highest preferential margin of 112,900 yuan and the lowest starting price of 327,000 yuan. If you are interested in buying this model, you may wish to click "Check the car price" in the quotation form to get a higher discount.

The BMW i4 adopts a unique front face design, and the air intake grille adopts a closed design, with sharp LED headlights, which shows a sense of modernity and technology. The body lines are smooth, and the waistline on the side is simple and dynamic, creating a sense of movement. The overall style is both luxurious and futuristic, which leaves a deep impression on people.

Bmw i4 adopts streamlined design, with body size of 4785*1852*1455mm, wheelbase of 2856mm, front tread of 1601mm and rear tread of 1630mm. The side lines of the car body are smooth, with 18-inch rims, which are 245/45 R18 in front of tyre size and 255/45 R18 in rear of tyre size, showing a dynamic style as a whole.

The interior design of BMW i4 is simple and exquisite, which highlights the perfect combination of luxury and technology. The steering wheel is made of genuine leather, which feels comfortable and supports manual adjustment up and down and back and forth to meet the needs of different drivers. The center console is equipped with a 14.9-inch touch screen with smooth operation and clear interface. Support the voice recognition control of multimedia system, navigation, telephone and air conditioner, which makes the driver more convenient during driving. The car is also equipped with multiple USB and Type-C interfaces, which provides convenience for passengers to charge. The front seats are made of imitation leather, genuine leather or leather /Alcantara mixed material, which provides a variety of choices. The front seats also have heating function, which brings passengers a comfortable driving experience. In addition, both the main seat and the auxiliary seat support a variety of adjustment methods, including front and rear adjustment, backrest adjustment, height adjustment, leg rest adjustment and lumbar support, to meet different driving needs. The front row is also equipped with wireless charging function, so that drivers do not have to worry about charging problems. The rear seats can be laid down in proportion, which increases the flexibility of storage space.

The BMW i4 is equipped with a powerful motor, with a maximum power of 210 kW and a peak torque of 400 Nm, providing excellent power output and driving experience for drivers.

The owner of car home spoke highly of the BMW i4, and he specifically mentioned that the vehicle has excellent sound insulation effect, strong power performance, and the appearance is even more king-class. Especially the volcanic red interior, he feels that the design is unique and not inferior to Mercedes-Benz.