Noise Control of Intake Valves
The intake valve of an internal combustion engine is designed to control the amount of air that is fed into the engines combustion chamber. The opening and closing of the intake valve is controlled by either a camshaft or a by an electronic control module, depending upon the type of engine. Intake valves can produce a significant amount of noise when opened, particularly during high speed operation. This noise can be unbearable at times and can lead to driver fatigue and other safety issues. To reduce this noise, a variety of techniques have been employed to control the intake valve noise.
One of the most effective techniques used to reduce intake valve noise is the use of acoustic damping materials. These materials are designed to absorb and dissipate the sound waves created by the intake valve. The material is usually mounted onto the intake valve itself or on the valve train to absorb and dampen the sound waves. By absorbing the sound energy, the amount of noise produced is reduced.
Another approach to reducing intake valve noise is to reduce the actuation speed of the intake valve. By reducing the actuation speed, the sound waves produced by the intake valve are reduced. This technique is especially beneficial when the intake valves are operating at very high speed, such as during high-performance racing applications.
Another approach to reduce the intake valve noise is to employ a variable ratio valve lift. Variable ratio valve lift systems can be used to reduce the speed of the intake valves during certain operating conditions. A variable ratio valve lift system takes advantage of the fact that the intake valves will remain open longer and produce less sound energy at lower speeds. By using a variable ratio valve lift system, the sound energy produced by the intake valves is reduced.
In addition to the above noise control techniques, the actual design of the intake valves themselves can be changed to reduce the noise produced. Intake valves can be designed with a quenching chamber, which is a special chamber designed to dissipate the sound energy created by the opening and closing of the valve. By dissipating the sound energy, the overall noise produced by the intake valves is reduced.
Finally, the engines exhaust system can be designed to reduce the noise produced by the intake valves. The exhaust system can be designed to absorb and dissipate the sound waves created by the intake valves. The exhaust system can also be designed to reflect the sound waves away from the listening area, reducing the overall noise output.
In summary, there are a variety of techniques that can be used to reduce the noise produced by the intake valves. By using acoustic damping materials, reducing the actuation speed of the valves, employing a variable ratio valve lift system, changing the intake valve design, and designing the exhaust system to absorb and dissipate the sound waves, the overall noise produced by the intake valves can be significantly reduced. This will not only reduce driver fatigue but also improve overall safety.
