January 29, 1886, the German Karl Mainz will be the development of its single-cylinder four-fuel engines installed on the car and a three patents obtained, the world truly began that day with cars. It can be said that the creation of a car engine.
The basic engine is constructed from a cylinder, Detroit 2, Link 3, 4, the main engine crankshaft components, each of at least two-valve cylinder, an intake valve (blue) and one exhaust valve (Orange) .
Valve Engine Valve device is an integral part of the body, work in the engine play a very important role. Fuel engine work has proceeded from Intake, compression, power and exhaust for the four process components. For continuous operation must be the engine to the four cycle process, the timing and sequence cycle work.
Two of them, the work process, intake and exhaust, and it is necessary to rely on the engine with gas agencies and accurately in accordance with the order of the work of conveying cylinder combustible gas mixture (gasoline engine) or fresh air (diesel engines), as well as from the combustion exhaust emissions.
The other two processes, compression and process for reactive power, it must be isolated from the outside world into the cylinder combustion chamber and exhaust channel, gas leaked from the engine to ensure normal work. Responsible for the mechanical work of the agency is in the allocation of gas valve. It can be compared to the respiratory system, the inhalation of breath and lack of it can not. Along with technological development, the car's engine speed has been getting higher and higher, the modern car engine speed usually ranging from 55 to more than a minute, and completed only four of 0.005 second time, the traditional two-valve has not competent in such within a very short time to complete ventilation, restrict the engine performance. Solve this problem is the only way to expand access to the gas space. In other words is to use space for time.
Multi-valve technology is the best way to solve the problem, until the 1980s to promote multi-valve engine technology only to have the overall quality of a qualitative leap. Multi-valve engine is a cylinder valve number more than two, two into an exhaust valve and valve-three doors, two exhaust intake valve and two-door four-valve, three and two intake valve of the exhaust valve of the five-door.
At present more cars on the multi-valve engine and four-valve. Four-cylinder engine with 16-valve, 6-cylinder engine with 24-valve, eight-cylinder engine has 32 valve. For example, in Japan LEXUS LS400 is the engine cylinder 32-valve 8. Valve increase the number will increase accordingly with gas agencies devices, more complex structures, generally two overhead camshaft cylinder in order to control both sides of the centerline of the valve chamber. Valve layout centres on both sides of the combustion chamber in the cylinder tilted position, which is, in order to maximize the diameter of the valve head, increase airflow through the area, improve the ventilation performance, create a spark plug in the central compact combustion chamber, to the mixture the rapid combustion.
Some people ask, since Valve good, why we did not see more than one valve 6-cylinder engine? Thermodynamic called a "screen area" concept, referring to the Park valve week multiplied by the valve lift, valve open space. "Curtain zone" that the greater the valve open space is, the greater the feed rate.
Audi 100 cars to the engine as an example, the four-valve "screens Area" value than the two-valve "screens Area" value, in the inlet to the state half of the state to exhaust the 7.0% 10. Of course, every one of the things it must have the scope valve is not to say that the more "screen area" of the bigger According to the experts when each of the cylinder valve to six, the "curtain district," it's worth it will be dropped, and the valve body more complex, the greater the cost.
?Therefore, at present, the multi-car engine fuel valve in each cylinder valve number are 3-5, which went four-valve is most common. The gasoline engine as an example, the multi-valve engine with the traditional two-valve engine, the former can be sucked into the air to mix more fuel combustion for power, fuel savings, faster emissions, less pollution emissions to increase the engine's power and the advantages of reducing noise, with the improvement of the environment and direction of development of energy-saving, multi-valve technology can rapidly widely.
?Multi-valve engine that fuel the rise of the beginning, some people think that it has a low technical flaws do not operate smoothly, the Boer, a German car company for the holders of this view. With technical improvements, multi-valve gas engines such technical defects have gradually overcome.
?Boer for the past few years the company's 944 S2 cars loaded with a four-cylinder four-valve engine, now, the world almost all the high-class cars are equipped with multi-valve engine fuel.