Explanation: rpm (revolutions per minute) engine can only work stably after reaching a certain speed, which is called idle speed. Above this speed, the engine works normally, and below this speed, the engine will stop working.
In addition, each engine will define a maximum speed, and the maximum speed of the engine varies with different structures. Increasing speed can increase power. The maximum rated speed that an engine can achieve usually corresponds to the maximum power, and the power value of the engine in technical data usually refers to the maximum power that can be achieved at the maximum speed. It is often easy to reach the highest rated speed when going downhill in low gear. The maximum rated speed is related to the engine displacement, but generally speaking, the engine speed level is on the rise.
At present, the average speed of four-stroke engine at idle speed is 600-800 rpm. As for the engine speed at the maximum power, according to the internal structure, displacement and number of cylinders of the engine, it is generally between 5000 and 6500 rpm.
The maximum rated speed of the car can reach an astonishing 12000 rpm, or even higher. The maximum torque value usually appears between 2500 and 4000 revolutions. Some engines will have so-called high-end "throttle loss" because the air intake can't inhale enough air. , causing natural speed limit. The appearance of the highest speed is often accompanied by valve flapping (valve floating), which not only brings uncomfortable noise, but also is harmful to the engine. Excessive speed will not only damage the valve, but also damage the piston and bearing and the lubricating oil film because the contact surface slides too fast.
In addition, if you downshift at high speed, the inertia force will suddenly increase. If there is no fuel power to follow up and pray for the balance of inertia force, it will easily lead to the fracture of connecting rod, piston and crankshaft. At present, due to laws and regulations and safety considerations, the maximum speed of the engine is forced to be limited to a low level. Limiting the maximum speed of the engine can effectively prolong the life of the machine and improve its reliability.
For example, Regal (Shanghai) 2.5GL 2.5LV6 engine has a maximum power of 1 12Kw/5600rpm, but when the engine speed reaches 4200rpm, the fuel supply will be automatically cut off, and when the vehicle speed exceeds 170Km/h, the fuel supply will also be limited, so it is 0 ~ 65440.
Extended data
It is the easiest to install RPM files in Linux system. Take the famous image processing software XV as an example, and its RPM package XV-3.10a-13.i386.rpm can be downloaded from the home page of the program.
In Terminal, the basic installation instructions are as follows:
rpm-I XV-3. 10a- 13 . i386 . rpm
If your internet speed is fast enough, you can also install the application software directly from the network, just add the appropriate URL path before the file name of the software.
As a software package management tool, RPM manages the data of all RPM program components installed in the system. We can also use RPM to uninstall related applications.
rpm -e xv
Commonly used parameters of RPM also include:
-VH: shows the installation progress;
-u: upgrade the software package;
-qpl: lists the file information in the RPM software package;
-qpi: lists the description information of the RPM software package;
-qf: Find which RPM package the specified file belongs to;
-VA: Check all RPM packages and find the missing files;
-QA: find the corresponding file, such as rpm -qa mysql.
Baidu encyclopedia: RPM