The higher the tire pressure, the more fuel-efficient, but we can't blindly pursue high tire pressure in order to save fuel.
Just like cooking dinner, you add some salt and chicken essence: "Wow! Fresh and delicious. " You try. If you add 2 scoops and 2 scoops, you can't eat. The more, the better.
The higher the tire pressure, the more fuel-efficient it is.
First of all, why is the higher the tire pressure, the more fuel efficient it is?
A large part of the car's fuel consumption is to overcome the resistance on the tires.
Wang Chuanzhu said in the paper "Performance Matching Analysis of Tire and Automobile" published in Tire Industry: Statistics show that the fuel consumption of tires to overcome rolling resistance accounts for about 20% of vehicle fuel consumption.
It's like: when running, a large part of your strength is used to overcome the friction between the sole and the ground.
The higher the tire pressure, the smaller the contact area between the tire and the ground, the smaller the friction force and the smaller the rolling resistance of the tire.
Yun Xin, Xie Weizhong and others published a paper "The Influence of Tire Pressure on Automobile Performance" in "Automotive Practical Technology" and also did experiments.
When the tire pressure is increased from 240kPa to 260kPa, the rolling resistance coefficient can be reduced by 4.4% to 7.7%, the rolling resistance is reduced, and the fuel consumption is naturally reduced.
In this way, the higher the tire pressure, as long as there is no puncture, it can save fuel.
What is the high tire pressure?
It's not that simple. In order to pursue the highest possible fuel-saving effect, there are hidden dangers
It will accelerate the wear of tires.
First of all, high tire pressure will accelerate tire wear and affect the service life of tires.
Huang Haijun, Nanjing University of Science and Technology, Master's thesis, "Research on Automobile Fuel Consumption Optimization under the Background of Experimental Design", said above.
When the tire pressure is too high, the contact area between the tire and the road surface decreases, which increases the load per unit area and accelerates the wear in the middle of the tire crown. In addition, too high tire pressure will reduce the ride comfort of the car and accelerate the wear and damage of the car parts.
It's like riding a bike. I'm so angry. Does my ass hurt? Right? Tires will soon break down.
Will affect the braking performance of the car.
Excessive tire pressure not only affects the service life of tires, but also affects the braking performance of automobiles to some extent.
Yang Chao of Jilin University has a master's thesis, "Study on Tire Steady-state Model Considering the Influence of Tire Pressure", and made an experiment.
What is the name of this dialect when the vehicle speed is 100km/h and the tire pressure increases from 250kPa to 350kPa? For "2.5 kg" and "3.5 kg", the braking time of the car will increase by about 0. 1s, and the braking distance will increase by about1.5m..
1.5m sound ok? But in many cases, this difference is very small, which determines whether the collision or accident occurs.
The fuel-saving effect will also decrease.
In addition, when the tire pressure reaches a certain level and then increases, the reduction of rolling resistance will become smaller.
Master thesis of Kunming University of Science and Technology in Han Yan is shared with you, "Research on Vehicle Economy Based on Driving Resistance", in which an experiment was done.
When the tire pressure increases from 2. 1bar to 2.4bar, the rolling resistance decreases the most. When the tire pressure increases from 2.7 bar to 3.3 bar, the rolling resistance gradually decreases.
It's like: if you study hard, it's obviously not that difficult to get from 50 to 80, but it's even harder to get from 90 to 99 with the same effort.
From this point of view, if the tire pressure is too high, the fuel saving effect will not be improved too much, even in the back.
What is the most suitable tire pressure?
Even if you really want to save fuel by increasing the tire pressure, it is best not to exceed the upper limit of the original standard tire pressure.
Li Can, Ayla Zhang and others published a paper "Discussion on Passenger Car Tire Pressure and Its Standards" in the Proceedings of the 16th Henan Automobile Engineering Science and Technology Symposium, which said.
When the vehicle is used under non-full load, the light-load tire pressure can be appropriately increased based on the standard tire pressure technology, and the upper limit of full-load tire pressure can be kept as low as possible to ensure driving safety and fuel economy.
For example, the tire pressure of the rear wheel itself is marked "2.7bar" over there, which is "2.7 kg" in vernacular. You have to hit 3.0, which really saves fuel.
However, it is easier to have a flat tire, the tire life is also reduced, and the car will be more bumpy. It's not as advanced as it used to be, and it belongs to such things as "picking sesame seeds and throwing watermelons".
By the way, we should also pay attention to tire life. High tire pressure or low tire pressure is not good for tire life.
I went to Bridgestone official website to check: tire pressure increased by 25%, tire life decreased 15% to 20%; Tire pressure is reduced by 25%, and tire life is also reduced by about 30%. So it is not good for the tire pressure to be too high or too low.
Therefore, I advise my friends not to go to 4S stores every time. When it grows to three or six months, you let it tire.
1 month, there is a tire shop or car wash shop nearby. Check the tire pressure and make it up when it is not enough. That's good.
Plug in hard and wide, and I also sell air pumps at home. It is not only small and portable, but also can preset tire pressure. When it is full, it can automatically stop and put it in the trunk. Interested friends can go to my house to buy one.
Pushing up the tire pressure can save fuel, but it is not recommended.
Generally speaking, although pushing up the tire pressure can really save fuel, it is not advisable to blindly pursue high tire pressure for fuel saving.
Not to mention the increase in tire wear, it will also shorten the braking distance. For the sake of driving safety, write as much as you want, without using your own brains. If it gets higher and lower, just follow it.