Automotive Black Technology Chapter 170: : Drag coefficient
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In the wind tunnel laboratory of the Nanjing Automotive Research Center, Li Fanyu and several students have worked together to fix the actual car-scale A4 clay model on the test bench.
The wind tunnel laboratory is not really a "hole". It is a combination of tunnels and giant wind turbines. If there is a huge knife and the room where Li Fanyu is located is cut horizontally, you can see that the entire laboratory is actually a back-shaped structure.
The room where Li Fanyu was located, with a large hole at each end, was actually just a section of the tunnel.
Although the staff of Nanjing Automobile are curious, they have already received instructions from their immediate superiors - stay away from people of good faith and do not provoke them.
So in the laboratory at this time, there were only Li Fanyu, Wang Dazui, and a few students.
In order to better distinguish the white smoke that marks the airflow, the 1:1 scale model of the A4 has been painted blue.
A student checked again, and after confirming that the preparations were correct, he came to Li Fanyu and stood next to him: "Brother, it's all done. Can we start?"
Li Fanyu asked Wang Dazui with his eyes, and the latter prepared the camera and nodded.
"Okay, let's start!"
As the working gate was closed, a windmill-like sound came from the two large holes in the room, and the giant fan began to operate slowly.
About ten minutes later, a huge airflow spurted out from the air outlet at one end of the laboratory.
Air resistance is the largest and most important external force that a car encounters when driving.
There are generally three types of air resistance that a vehicle encounters while driving; the first is the resistance caused by the airflow hitting the front of the vehicle. This kind of resistance is easy to understand. You can feel it if you hold a wooden board and walk against the wind on a windy day. The second type is frictional resistance, but this frictional resistance is so small that it can almost be ignored.
Then there is the shape resistance. Generally speaking, when the vehicle is driving at high speed, the shape resistance is the main source of air resistance. This resistance is caused by the airflow passing through the car body at high speed, creating a vacuum zone at the rear of the car. Vacuum will produce pulling force, so generally a car with a better tail streamline will be less affected by the vacuum zone and run faster.
This wind tunnel test was mainly conducted on frontal resistance and shape resistance.
Six streaks of white smoke blew against the A4 model along with the strong wind. Looking at the slowly rising wind power value on the instrument, Li Fanyu felt a little anxious.
Because the appearance has been changed after all, if a mistake causes excessive wind resistance, then all the work and efforts during this period will be in vain.
Wang Dazui took the SLR, adjusted the focus slightly, and took two pictures of the model. When he turned around and saw Li Fanyu looking a little anxious, he smiled and patted him on the shoulder.
"Brother, don't worry. This is just the first test. It doesn't matter if the values are not good, just go back and modify it. None of the models I have followed and reported before can be finalized in one go."
Li Fanyu forced a smile and nodded.
Wang Dazui's comfort did not have much effect, because Li Fanyu was too concerned about this test.
You know, regardless of the performance of the engine, the drag coefficient is the decisive factor that determines the fuel consumption and speed of a car.
Let's put it this way, when a car is driving, the resistance it has to overcome include the frictional resistance of parts, the road resistance produced by the tires, and air resistance.
But as the vehicle speed increases, air resistance becomes the largest driving resistance. When the vehicle speed reaches more than 200KM/H, air resistance accounts for almost 85% of all driving resistance!
Cars, especially sports cars and sedans. If the drag coefficient is not controlled well, the fuel consumption will skyrocket.
Li Fanyu was not afraid of failure, he was afraid that he would not have time. The production lines of several workshops have been decided, and Pan Qiang visited several domestic production line placement companies but could not find a suitable one. In the end, An Ning came forward and introduced an old French production line through foreign relationships. Although it is expensive and broken, it can be used at any time.
Just such a production line cost almost Li Fanyu's entire worth. More than 400 million, plus the subsequent installation and debugging, it would be good to stop at 500 million.
Now the entire Zhengxin is relying on the income from the second-hand car platform. If the A4 takes a year or two to come off the production line, the company will have no new revenue, and it will really be a dog-lead rhythm.
The wind resistance coefficient test is automatically calculated as the wind speed in the wind tunnel gradually increases. Li Fanyu looked anxious, so he turned and walked to the door.
Wang Dazui saw that he was acting strangely and knew that he was anxious, so he took out a cigarette from his pocket and handed it to him.
"Go out and smoke a cigarette to get some fresh air. The results will come out when you come back later."
Li Fanyu didn't smoke, but couldn't bear to be upset, so he took it in his hand and turned around and went out.
The sky outside was a little hazy, and it looked like it was going to snow. He looked around and sat down on a stone pier at the entrance of the laboratory.
Wang Dazui is an old smoker and cannot stop smoking one pack a day. So even though this guy’s salary now exceeds 40,000 yuan a month, he still smokes a box of Hongtashan worth 7.50 yuan.
Li Fanyu took out one and stuffed it into his mouth, then lit it in a decent manner. As soon as I took a puff, I was choked by the spicy smoke and felt like I was vomiting.
He hurriedly threw the cigarette on the ground, covering his mouth and coughing for a while.
Hey, it would be great if the production capacity of the X super production line could keep up.
He suppressed the feeling of nausea and thought dullly.
But as soon as he thought about it, he immediately gave up the idea.
My choice is not wrong. Sooner or later, I will go down this road. I can't always count on X black technology.
Although Xapp can create huge benefits in a short period of time and make quick money, it is water without roots. If you want to achieve the goals you have set, you will have to take this road sooner or later.
Now that you have made your choice, you must go on unswervingly. The rest is left to time to verify whether it is right or wrong.
He sat silently on the stone pier, took out the eyes from the cigarette case one by one, and crushed them.
Time passed like this minute by minute, and crystal snowflakes fell from the sky at some point.
I don’t know how long it took, but a student named Wang Rui came out of the laboratory. After looking around, he saw Li Fanyu sitting with his back in the corner and ran over.
"Brother! The test results are out!"
Li Fanyu was startled by his shouting. He quickly came to his senses and stood up suddenly.
He threw the tobacco leaves in his hand to the ground and asked anxiously: "How much!?"
"What do you think?"
Li Fanyu had a mouthful of old blood stuck in his chest; I guess you are my sister! How long have you been playing innocently with me? !
He is about the same age as the students. These people always like to joke after getting to know each other well. Wang Rui knew that he was anxious, so he deliberately whetted his appetite.
That would be enough in normal times. Li Fanyu was worried and had no intention of playing with him, so he decided to kick him.
Wang Rui saw that Li Fanyu was really anxious and quickly stepped away: "Brother, have mercy! The drag coefficient is 0.23!"
0.23?
Beautiful!
When Li Fanyu heard this number, he felt that the sky was bright. (To be continued.)