What are the principle of variable valve? Variable valve timing and lift what are the advantages of the technology

by:DEFUS     2020-06-22
Automobile engine valve timing mechanism and technology, also known as continuous variable valve timing system, the high performance engine is generally equipped with the system. Through equipped with control and execution system, the system of engine CAM phase or adjusted valve lift, thus achieve the goal of optimization engine distribution process. The next and we explain the principle of variable valve have? The advantages of variable valve timing and lift technology have? What are the principle of variable valve for high speed and low speed, the Angle of the valve timing on engine thermal efficiency and power are obvious, the influence of high speed can make full use of the air intake of inertia and improve the efficiency of air inflow and scavenging, so the valve on night off early, low speed, on the contrary, most engines now have the technology. The origin of the variable valve piston four-stroke engines are made by four air intake, compression, power, and exhaust stroke is complete, we focus on the valve opening degree of the engine air intake. Cylinder inlet is the basic principle of 'negative pressure', is the difference of gas pressure of cylinder inside and outside. When the engine running at low speed, the valve opening degree must not excessive, such easy to cause the cylinder inside and outside pressure equalization, negative pressure decreases, and thus intake enough, for the valve's work, the degree of 'small open' needs by way of short stroke control; And on the contrary, high-speed rotating speed at 5000 RPM, if the valve is still harm sheepishly refused to open, the engine air intake will be blocked, so we need long stroke valve lift. More often than not, the engineers should give attention to both the torque characteristics of the engine at low speed area, and want to extract the power characteristics of high speed area, can only take a 'compromise' thinking, in the end the engine high speed have no power, short of torque at low speed. So in that case, you need a device to adjust the valve lift, or what we say 'variable valve timing technology. The technology can not only guarantee the high torque at low speed, and can obtain high power, high speed for engine is a great breakthrough. In the 80 s, many enterprises begin to research into the variable valve timing, 1989 Honda was first issued a 'variable valve with gas phase and valve lift electronic control system', the English full name 'VariableValveTimingandValveLifeElectronicControlSystem, also is our common VTEC. Since then, the development companies, to today has been very mature, Toyota has developed the VVT - Almost every enterprise has its own variable valve timing technology. A series of variable valve technology, although different brand name, its design ideas are very similar. Variable valve timing and lift technology what are the advantages of the engine valve is usually driven by a camshaft, ordinary engine with variable valve timing technology is concerned, the inlet and exhaust opening and closing time is fixed, but the valve timing is difficult to take into consideration of the fixed to the working condition of engine at different speed and needs. Said in front of the engine intake and exhaust processes are like human breathing, but the 'breathing' rhythm of fixed block to promote the efficiency of the engine. If you are involved in long distance race, can deeply understand the importance of breathing rhythm of body - — Too fast or deliberately holding your breath can increase fatigue, reduce running desire. So, when we are in a long distance race is often need to constantly to adjust breathing rate according to the running pace, so that always provide enough oxygen to body. For automobile engine, this truth applies. Variable valve timing and lift technology is to let the engine under various load and speed adjustment 'breathing', so as to improve dynamic performance, increase the combustion efficiency. More about 'what are the principle of variable valve? Variable valve timing and lift technology content, what are the advantages of the 'all hope useful for everyone.
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