Chapter 165： Competition heats up

"I am the president of the university (

(Note: The math and analog competition involved in the novel is not taken from this year, but from last year's topic. There is a lot of information about last year on the Internet, so I will take the 2019 math and analog competition)

To solve the problem, you must first analyze the problem.

There are three questions in total.

Among them, question 1 and question 3 also have 2 small questions to summarize:

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

(2) Under the working times of the injector, the size of the high-pressure oil pipe and the initial pressure given in Question 1, determine the angular velocity of the cam, 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 injector, each nozzle has the same fuel injection law, how should the fuel injection and fuel supply strategy be adjusted? Please give the control scheme of the high pressure oil pump and pressure reducing valve.

【Question one:

The first small question: 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 check valve each time. Second, it proposes...

Second small question: The question asks us to adjust the system pressure from 100MPa to 150MPa at different times and make it stable. This requires us to first...]

[Question 2: This question redefines the oil inlet and outlet method. At this time, the oil inlet method will be related to the angular velocity of the cam, which requires us to re-describe the oil inlet and outlet method on the basis of Question 1, and set the decision variables... 】

[Question three:

The first small question: On the basis of the second question, a new fuel injector is added to the system, and the oil output mode will be changed. Because of whether the fuel injection time of the newly added fuel injector is the same as...

The second question: On the basis of the previous question, a pressure relief valve is defined. Since the problem does not accurately describe how it works, we need to define how the pressure relief valve works...]

After the analysis of the problem is completed, then clarify the idea of ​​​​the problem, and then divide the labor, solve the problem and model, find the literature, prepare the thesis template, and write the program.

"Zhang Lei, go to CNKI to check some literature for me, and prepare the paper template."

Lu Zhou didn't lift his head and continued, "Old Zheng, you should familiarize yourself with the next topic first. After I build the model, you can prepare for programming."

The two nodded and waited.

Just then, there was a knock on the door.

The three looked at the door and saw Chen Hao standing impressively.

Chen Hao walked in with three cups of Starbucks in his hand.

"Classmates, what's the matter, is the problem difficult?" Chen Hao put the coffee on the table and said with a smile, "Drink some coffee to refresh your mind, I also ordered takeout of Kaifeng dishes for you. I can come."

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

On the contrary, Zheng Tianyu scratched his head a little embarrassedly and said, "Principal, this is too expensive for you."

Now, in this classroom, not only a 3-tatami bed is made in the corner, but a box of instant noodles, red bull and snacks are piled on the side.

This preparation made the three of them feel really warm.

I also made up my mind that I must achieve a good result.

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

After a while, I read it, and I also had a little belly draft in my heart.

During the competition, it is impossible to discuss topics with the instructor and outsiders, so Chen Hao cannot 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 quite simple. But I can't teach you guys, come on, I'll look at Lu Zhou's problem-solving ideas first." Chen Hao finished speaking easily and stood up behind Lu Zhou.

Lu Zhou is waving one hand on the A4 paper, and the formulas on the blank paper are getting more and more. While calculating on the paper, he muttered:

"Since the pressure change of the fuel is proportional to the density change, and the title gives the relationship between the proportional coefficient and the former, then the equation of state of the fuel can be obtained:

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

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

"Ok." Zheng Tianyu just took a sip of coffee and quickly typed on the keyboard according to the data given by Lu Zhou.

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

rhospan=[0.850.9];

p0=100;

[rho, p]=ode15s(@(rho, x)(fitresult.p1*x^6+...

...

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

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

After all, time is tight, only 72 hours.

Chen Hao looked at Lu Zhou's problem-solving ideas and nodded, somewhat relieved.

"Come on, do the questions well, and remember to pay attention to rest."

After the warning, Chen Hao left directly.

And because the topic of this Mathematical Modeling Contest is too perverted, the Internet is directly frying!

On CNKI, Wanfang and other journal websites, the top three most searched keywords are: airport taxis, concentric drums, and high-pressure oil pipes.

These three are the three questions of this year's Mathematical Contest in Modeling.

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

Discussions on the topic of digital and analog competitions on Weibo are also getting hotter.

"The menstrual period disorder is half a month ahead of schedule The chair in the computer room has been stained with blood. It's just a good job, and none of the key issues have been resolved..."

"The carnival of science and engineering schools, the whining of finance and economics schools!"

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

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

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

Beijing, in the computer room of Peking University.

Although it is rumored that top elite schools like Tsinghua University and Peking University do not like to participate in external 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 resumes of the top academics in those prestigious schools are all with award-winning records and journal papers...

There are 21 people in seven groups in the computer room, and each group is rubbing shoulders and pointing at the higher education club cup.

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

"Choose question A." Lu Ziming explained the reason indifferently, "Question A is the most difficult, we are going to start, this time we must win the Higher Education Club Cup."

The three majors in the team are mathematics + physics + letter science. They face the problem of high-pressure oil pipes without difficulty at all.

Their opponent is...

Lu Ziming looked around at the classmates in the computer room with sharp eyes.

As long as you defeat the classmates in the same computer room, as well as the top teams of Tongji, Nankai, NTU, and Huake, the championship will be secured!

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

ps: Ask for a recommendation ticket! There are still more than 300 votes to break 10,000, please support! ! !

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