I Am the President of the University

The latest website: (Note: The mathematical model competition involved here is not taken from this year, but from last year's topic. There are more information about last year on the Internet, so I will take the 2019 digital model competition)

There are three questions in question A.

There are also two small questions in question one and question three. The summary is:

(1) When the pressure in the high-pressure oil pipe is stable at 100MPa, how to set the opening time of the one-way valve each time? The pressure in the high-pressure tubing increases from 100 MPa to 150 MPa and stabilizes at 150 MPa after about 2 s, 5 s, and 10 s, respectively. How should the opening time of the one-way valve be adjusted?

(2) Determine the angular velocity of the cam under the number of injector operations, the size of the high-pressure oil pipe and the initial pressure given in question 1, so that the pressure in the high-pressure oil pipe is as stable as possible at about 100MPa.

(3) On the basis of Question 2, add another fuel injection nozzle. Each nozzle has the same fuel injection pattern. How should fuel injection and fuel supply strategies be adjusted? Please give the control scheme of the high-pressure oil pump and the pressure reducing valve.

To solve a problem, you must first analyze it based on the problem, and the analysis is not difficult for Lu Zhou.

It didn't take a while to finish the analysis of the problem.

[Question one, the problem defines a constant oil outlet method, and the defined oil inlet method is only related to the system pressure and the opening time of the one-way valve each time. Secondly...]

[Question two, this question redefines the way of oil inlet and outlet. At this time, the way of oil inlet is related to the angular velocity of the cam. This requires us to re-describe the way of oil inlet and outlet on the basis of question 1, and set the decision variables... 】

[Question 3, this question is based on question 2, and a new fuel injector is added to the system, so the fuel delivery method will be changed, because whether the injection time of the newly added fuel injector is the same as...]

Next, clarify the idea of ​​the problem, and then start the division of labor. Problem-solving modeling, searching literature, preparing paper templates, and writing programs.

"Zhang Lei, please go to CNKI to check some documents for me, and prepare a paper template."

Lu Zhou didn't lift his head and continued, "Old Zheng, you will be familiar with the next topic first, and you will be ready to program when I build the model."

The two nodded and waited.

At this moment, a knock on the door sounded.

The three of them looked towards the door and stood Chen Hao impressively.

With three cups of Starbucks in his hands, Chen Hao walked in with a smile.

"Students, how's it going, is the topic difficult?" Chen Hao put the coffee on the table and said with a smile: "Drink some coffee to refresh yourself. I also ordered Kaifeng dishes for you. I'll just wait. I can get there."

"Thank you principal!" Zhang Lei stepped forward with a happy face and distributed the coffee.

But Zheng Tianyu scratched his head embarrassedly and said, "Principal, this is too costly for you."

Now in this classroom, not only is there a three-tatami bed in the corner, but a box of barreled instant noodles, red bull and snacks are stacked on the side.

This preparation made the three of them really warm.

I also made up my mind to get a good result.

"It's okay, the game is important, I'll look at the topic." Chen Hao said with a smile, sitting in the position where Zhang Lei let out, looking at the topic on the screen.

After reading it in a while, I also typed a bit in my heart.

During the competition, it was not possible to discuss topics with the instructor and outsiders, so Chen Hao could not help them.

Zheng Tianyu looked at Chen Hao curiously and asked, "Principal, do you think this question A is difficult?"

"It's okay, it's pretty simple. But I can't teach you guys, come on, let me first look at the student Lu Zhou's problem-solving ideas." Chen Hao finished speaking lightly, standing behind Lu Zhou.

Lu Zhou was waving a hand on the a4 paper, and there were more and more formulas on the blank paper. Calculating on the paper, talking about:

"Since the change in fuel pressure is proportional to the change in density, and the question also gives the relationship between the proportional coefficient and the former, the fuel state equation can be obtained:

dP/dρ=E(p)/ρ, where P is the pressure and ρ is the density. "

After chanting, Lu Zhou looked up, looked at Zheng Tianyu beside him, and said, "Old Zheng, you can use the software to help me calculate p(ρ)."

"OK." Zheng Tianyu just took a sip of coffee and quickly tapped the keyboard based on the data given by Lu Zhou.

[[Fitresult, gof]=createFit(p, K);

rhospan=[0.850.9];

p0=100;

[rho,p]=ode15s(@(rho,x)(1*x^6+...

...

figure;plot(rho,p);(\'fuel density(\'pressure p\')】

As for Chen Hao on the side, the two of them were too busy to take care of them.

After all, time is tight, only 72 hours.

Chen Hao nodded as he looked at Lu Zhou's thoughts on solving the problem, somewhat relieved.

"Come on, do the questions well, and remember to take a break."

After the exhortation, Chen Hao left directly.

And because the topic of this year's mathematical modeling contest is too perverted, it is directly fried on the Internet!

On the journal websites such as CNKI and Wanfang, the top three most searched keywords are: airport taxi, concentric drum, high-pressure oil pipe.

These three are the three questions of this year's mathematical modeling competition.

Zhihu also raised a hot search, "How to evaluate the 2020 Mathematical Contest in Modeling?"

Discussions on the topic of digital model competition on Weibo are also getting hotter.

"The menstrual period is disordered half a month earlier, and the chair in the computer room has been stained with blood. It's fine if you do a good job, none of the key issues have been solved..."

"The carnival of science and engineering schools, the wailing of financial schools!"

"I can't understand question A, question B won't count, and question C has no data."

"I made up fluid mechanics, hydraulic transmission, and process control in one night, and I still looked confused when I looked at the problem."

"From the opening of the question to the change of the question, and then from the change of the question to making up..."

Peking University at 2 am.

Every computer in the computer room is lit, and it seems that every teammate participating in the competition will not feel sleepy.

Although it is rumored that scholars from top universities like Tsinghua and Peking University do not like to participate in outside competitions and are more keen on intramural competitions, the first place in the national competition is still very attractive.

Especially when competing for special scholarships, the top academic bachelors in those prestigious schools have all their resumes and journal papers...

There are seven teams of 21 people in the computer room.

The team member beside Lu Ziming asked, "Ziming, which question do we choose?"

"Choose question A." Lu Ziming said lightly. "Question A is the most difficult. We are ready to start. This time we must win the Higher Education Club Cup."

The three majors in the team are Mathematics + Physics + Letters. Facing the problem of high-pressure tubing, there is no difficulty at all.

Their opponent is...

Lu Ziming looked around the classmates in the computer room, his eyes were sharp.

As long as you beat the classmates in the same computer room, as well as the top teams of Tongji, Nankai, Nanda, and Huake, the championship will be stable!

As for the other schools...sorry, they are not among the imaginary enemies.

...

"Do you think those students at Peking University will stay up late to solve problems?" Zhang Lei yawned and looked at Zheng Tianyu.

On the table next to him, there are family buckets of Kaifeng dishes and wrapping paper for hamburgers.

"Should it?" Zheng Tianyu answered casually while staring at the screen.

He doesn't know if Peking University's Xueba will be a student. He just wants to know if he can win the championship this time.

"Elbow, the two programming of the first question are already OK here."

Lu Zhou was still immersed in the calculation of the problem~www.readwn.com~ during which he looked up at Zhang Lei, and said: "Zhang Lei, the data of question 1 model and programming are all handed over to you. You can give part of the paper of question 1 as soon as possible. Write it down."

"I'm calculating problem two." Lu Zhou said, looking at the time, and continued: "It will be calculated before about 6 o'clock, and I plan to squint after it is calculated."

Zheng Tianyu nodded and said: "Okay, then I will go to bed for a sleep meeting, set an alarm clock at 6 o'clock and start to do the programming part of the second question."

"Lao Zhang, after you finish writing part of the essay for question 1, go to bed and call you to get up after I have compiled the programming for question 2."

Zheng Tianyu got up, exercised his muscles and bones, and slept directly on the bed beside him.

The night gradually dissipated, and the day fell...

ps: Ask for a recommendation ticket! It's more than 300 votes to break 10,000, please support! ! !

I checked the information in this chapter for more than 2 hours in the early morning, and I really vomited, but don't spray water...I quickly transitioned out, it was too difficult to write the details.