Chapter 369 Fault Recurrence, Problem Confirmed
“Okay, stop.”
Zhu Xuefeng already knew in his mind that the engine cannot increase the speed without cooling down. This is a diesel engine , the temperature has a great influence on the compressed mixed air in the cylinder, and the cylinder may explode.
The experiment lasted less than two minutes in total. The temperature of the cylinder did rise a lot, but in general, it was not completely high. After all, the time was too short.
“The time is too short, and the engine temperature has not had time to really rise, which means nothing.”
“It is that such a short time cannot prove high reliability.”
< br>"The cylinder is hot, and the fault has not recurred. What did this experiment prove..."
There was a lot of discussion at the scene, and everyone expressed their opinions. The navy representative came over.
"Comrade Xiao Zhu, what exactly did your experiment just prove? I am very curious about what conclusion you came to. Can you share it with everyone."
"Representative Niu, I have a preliminary conclusion, and I still need to discuss it with the seniors.”
At this time, Director Zhao also hurried back with his people. They checked the entire casting process and found that there were no major problems.
Finally, a release form was found. The factory also admitted that the accuracy was a little worse than the drawing requirements. The designer and the military both recognized it after passing the review and signed the "Super Tolerance Substitute Release Form".
A blackboard was set up at the experimental site, and Zhu Xuefeng drew an inverted tree branch on the blackboard according to his own sketch.
"Dear seniors and experts, I have some ideas here. I am trying to show my embarrassment here. I hope you won't laugh at me."
"I call this picture a fault tree. , also called a fishbone diagram, this is a fault, let’s analyze the reason for holding the tank..."
There are many discussions below, and there are many methods of analysis. I have never seen it so directly and clearly. It does look like a tree. It is also like removing the fish bones from the flesh. It is a good method. This way the logic is indeed clearer and more organized, and it is not easy to miss relevant possibilities.
"So your final suspicion is still the cooperation between the cylinder and the piston. Although your verification this time is strange, it seems to have verified that the cooperation is okay."
Facing the doubt, Zhu Xuefeng said with a smile . "You are right to say that. It can still operate normally at 7,000 rpm. There should be no problem with the coordination."
The designer did not agree with Zhu Xuefeng's terminology and pointed out on the spot.
“There should be no problem in what it means. Many engines have this matching size, so there should be no problem.”
"Senior, our analysis is not over yet. Do you want to hear if this possibility exists?"
"With the normal size, there is no problem. When the temperature of the engine block rises, the water cooling system starts to work. The heat dissipation effect of the cylinder and the piston is inconsistent, causing the piston to get stuck! "
The designer still can't understand, "But our previous matching dimensions were like this, and we have verified it many times, so there is no problem."
"About this, I would like to explain three issues. Through measurement, the dimensional deviations of the cylinder and piston are slightly larger than the design requirements."
Looking at the factory personnel raising their hands below, Zhu Xuefeng, although Even if you are interrupted, you still give a polite gesture.
“Please tell me if you have anything to say.”
“This time the designer’s accuracy requirements have been improved a lot. This time we also used your factory’s technology in production, and the accuracy has also been improved a lot. , It should be better matched than the previous engine, although it is a little worse than the designer's requirements, this is the highest accuracy our factory has achieved in recent years."
Zhu Xuefeng nodded and pointed to the designer who was eager to explain. .
"Please also express your opinion."
"Their accuracy is as high as this, which is much better than before, so we signed a concession and let it go. We just press your factory The accuracy requirements were raised, and even if they didn't meet them, we don't think that was the reason."
The military also nodded. They signed the agreement after discussing the concession and release before they could start the next step.
Zhu Xuefeng retracted his hand, "I also agree with you. This is not the root cause. Through measurements, I know that the piston has a negative tolerance. This error will cause a slight decrease in engine power and will not cause cylinder locking."
“Let’s talk about another issue. Previous engines have not reached such a high speed, and the friction heat was underestimated, which also has a certain impact.”
No one objected at this time, Zhu Xuefeng continued said.
“I think there is a problem with the design of the matching dimensions. The new material used this time is slightly different from the expansion coefficient of cast iron in the past. Using mature matching dimensions is a hidden danger at this time.”
“It is not obvious when the temperature is not high. The speed continues to rise and the temperature changes sharply. Then water cooling leads to inconsistent temperatures between the cylinder and the piston, and the problem arises. I don’t know if all seniors and experts agree with me. ….”
It became quiet all of a sudden. Everyone is a leader in the industry. A different expansion coefficient explains everything. This experiment indeed proved that when the temperature is the same, there is no big problem. When the temperature difference occurs, , the fault will definitely occur.
After a while of discussion, applause slowly broke out and gradually became louder and louder. Unexpectedly, it was the change in the material that caused the expansion coefficient to be different. The size that did not cause problems before was now inappropriate. .
“Of course, this is just our current judgment. Is it a problem with heat dissipation and size matching? I think we should verify it with a test drive.”
“Didn’t we verify it just now? ?”
Zhu Xuefeng shook his head, "This speed has only reached 7,000 rpm, which is far from the designer's requirements. The cylinder has been damaged just now and is not suitable for high-speed experiments. Didn't we make three sets at one time? Those two sets are just here. Do a comparative experiment. "
Everyone feels a little distressed. This one requires a lot of money. If we test two more, everyone will feel distressed.
"Representative Niu, those two units should be the same as this one. They cannot be put into normal use. Although they have not been tested yet, they must be considered waste products."
Although Zhu Xuefeng's words were harsh, but Thinking about it, it can only be a waste product. Representative Niu nodded.
"Then let's try it according to the experimental plan of the rolling mill to ensure that we find the problem accurately."
The two engines are placed far away, more than twenty meters apart, in order to Avoid surprises.
“According to the plan, we start directly from 5,000 rpm. Each speed lasts for ten seconds and changes once every 1,000 rpm. The No. 1 machine does not need water cooling for heat dissipation, and the No. 2 machine does not use water cooling for heat dissipation.”
Speed speed Soon it reached 7,000 rpm again, and surprisingly, none of the cylinders held the cylinder.
"Rise to 8000 rpm."
Zhu Xuefeng has been staring at the hot piston carefully. There was a burst of exclamation from outside, it was too dangerous. He was surprised that there was no lockup just now. Now an accident occurred. The No. 1 engine was still running normally at 8,000 rpm. The No. 2 engine was forced to shut down after holding on at 7,000 rpm for a few seconds. A cylinder lock occurred and the fault recurred.
"Rise to 9,000 rpm, maintain for one minute, and shut down."
The accident occurred again, and the No. 1 unit was still working normally at 9,000 rpm! After a minute, everyone was relieved when the phone was turned off.
The shipyard representative was a little confused. "Why is this happening? It can run without cooling, but malfunctions with cooling? But if it does not dissipate heat for a long time, the machine will also burn out."
The representative of the diesel engine factory still knew very well. After all, he is an industry insider. "Without heat dissipation, everyone will expand in the same way. Of course there is no problem. Once the heat is dissipated, the design of the matching size will of course come out."
This experiment once again verified the existence of the coordination between temperature, expansion coefficient and matching size. Question, the designer also blushed.
“I’m sorry, it’s true that we didn’t think it through well and ignored this problem. We will recalculate it when we get back and try to make it right as soon as possible.”
The designer focused on the strength and toughness of ductile iron , it was true that significant modifications were made to the original engine, but this inconspicuous factor was ignored.
“Our factory has several sets of product matching dimensions that can be provided for your reference. Of course, individual engines vary greatly, so this is just a reference.”
The designer understands this truth , I can’t copy it, but I still want to thank you.
Logically speaking, there would be nothing left to do with the steel rolling mill, but the factory, the military, and the designer all proposed that the comrades in the steel rolling mill should stay for a few more days to wait for the new drawings and samples to come out, and then leave after a smooth test run.
There is no way, a few people can only stay. This is a key task and must be successful. Zhu Xuefeng was specially invited to participate in the redesign of the engine.
I have learned a lot. This kind of giant engine is something Zhu Xuefeng has never thought about or been exposed to. Many ideas and ideas have strong guiding significance. .
In the remaining few days, Zhu Xuefeng and others briefly visited the shipyard under the leadership of the military and the factory.
Actually, it’s just a look outside. You are not allowed inside the factory.
"This is the ship this time. How about it, it's big."
A completed large ship is parked in a large factory building in a hidden bay.
"It is indeed quite big, it should be a frigate."
"Well, this is the latest frigate, just developed, weighing 115 tons. If our own engine is built, this The speed should be able to reach 35 knots. By then, no one in this area can outrun us in terms of speed. Even the bald eagle is here and it can’t outrun us.”
Indeed, the speed of 35 knots is amazing. , at this time, there were no ships that could run so fast. The key was that this frigate was small, only 115 tons, but it was still enough for offshore patrol and defense. There were no overly powerful naval ships in this area.
"Originally we wanted to import an engine. Lao Maozi's one is cheap and powerful, but it can only run for 450 hours and the engine will be scrapped. There is no way."
"Can such a small working time be called an engine?"
Zhu Xuefeng and his party were all surprised. According to this statement, he would be dead after running for less than twenty days. What the hell is this?
Representative Niu smiled awkwardly, "This engine is for torpedo boats, so it is designed to have such a long life." (Historical fact)
Everyone suddenly realized that torpedo boats It looks fast and sassy, but its existence is tragic.
At this time, the navy only had a reasonable number of torpedo speedboats. The weapons for offshore warfare were half-suicide speedboats. There was no way, the navy was poor.
The movie I watched as a child came to mind involuntarily. A group of torpedo speedboats circled around a giant destroyer, known as the wolf pack tactic, and forced the overwhelming destroyer to retreat. It was really sad, and the future generations. There is no essential difference between car bombs.
"Yes, the navy is still too poor and can only develop some offshore combat capabilities, mainly defensive."
Representative Niu nodded, "So later we wanted to import Minde The engine has 1,300 horsepower, but the gap is too big. We need at least 200 units, and the country can't afford it, so we gritted our teeth and developed a new engine."
"We have to thank you, the rolling mill. , we have developed new materials, new technologies, and technologies to improve engine power in a timely manner. Without these three, we would not be able to do it even if one of them is missing.”
If the Navy's engine can succeed this time, it is true that the three key technologies of the steel rolling mill are indispensable.
“After we designed it, we calculated that the maximum power can reach 1,600 horsepower, which is stronger than the imported one. Haha, it doesn’t cost a lot of money. When it is successful, we will report it to your factory. "
…
"Although our ship is not big, the naval guns and anti-aircraft artillery on the ship are very powerful. In our part of Asia, there is no more firepower than it. Fierce.”
Zhu Xuefeng also had the impression that this should be the Type 62 frigate of later generations, but he didn’t know if it was the final version. A total of nearly four hundred ships were produced in later generations, and seventy or eighty of them were sold out. , the rest have been regarded as the main ships of the navy for twenty years.
Although the Navy also has a few destroyers of several thousand tons obtained from Lao Maozi, they are too few and too precious after all.
The family is too poor to let these treasures participate in the war. It is more about cultivating talents for the navy. The ones who really pick up the bricks and rush forward to fight are those small gunboats with tens or hundreds of tons.
Thinking of the Navy using small gunboats to fight hand-to-hand with the enemy, I feel a little sad in my heart. I still remember the tragic scene of the fearless fishing boat ramming the Fuso frigate, and then returning to the port with its bow gloriously deflated.
The lack of large ships cannot be solved in a short time. The multiple difficulties of national strength and technology can only be left to time.
Looking at the neatly arranged small speedboats not far away, it goes without saying that these are torpedo speedboats. Sure enough, I heard the introduction from Representative Niu.
"This is our torpedo speedboat, which is currently the largest in the world in number. Its speed can reach up to 50 knots. No ship can escape its pursuit."
The rest of the words are not said, and everyone knows that if we catch up, we will catch up. There is a high probability that he himself will also be sacrificed. He has no defensive capabilities. The main weapon is torpedoes. The soldiers on the speedboat only have conventional light weapons, covered by the firepower of naval guns and ships...
The torpedoes of this period were also very unreliable, and the imitations were very immature. After Da Maozi left, the progress was not smooth, so every torpedo was a treasure and had to be fired closely.
…
The waterproof barrier of the torpedo boat being processed still inspired Zhu Xuefeng a lot. He didn’t know much about ships and ship structures, but the partition compartment to prevent sinking made him immediately Reminds me of the assault boats that were always available in later generations.
By the way, if there were a batch of assault boats in the summer of the next year, how many families and lives would have been saved. As a later-generation Beijinger who has experienced the baptism of floods, I know very well.
The overwhelming information made him remember that floods will occur in many places in the mainland in the next two years, especially the year after that, that is, in 2003, there will also be major floods caused by rare precipitation in Beijing, Hebei, and Tianjin. Countless people were displaced, causing great chaos in the capital.
(End of this chapter)