Patent Application
20060112939
1. Field of the Invention
The present invention relates to an air intake system for an engine. In particular, the present invention relates to an air intake system for an internal combustion engine. The present invention also relates to an auxiliary intake device of the air intake system for an engine.
2. Description of the Related Art
A typical internal combustion engine generates power by combusting air-fuel mixture in a combustion chamber in each cylinder. Reciprocating motion of a piston in the respective cylinder drives a drive shaft to thereby turn the wheels of an automobile with the engine. The air-fuel ratio is one of the important factors of smooth operation of the engine. The theoretical ideal air-fuel ratio is about 17:1. However, the actual air-fuel ratio varies in response to the speed of the engine. It is therefore the goal of the designers in the art to obtain the optimum air-fuel ratio at different speeds.
Generally, fresh air is introduced into the combustion chamber during the downward stroke of the piston, which results in a vacuum to suck ambient air into the cylinder. However, the intake valve(s) is(are) closed before sufficient air enters the combustion chamber when the engine exceeds a certain speed. The higher the speed of the engine is, the poor the volume efficiency is. A solution to solve this problem is to forcibly introduce fresh air into the combustion chamber to increase the pressure in the combustion chamber. By this arrangement, more power is output, as more air is introduced into the combustion chamber. There are two approaches for boosting the pressure in the combustion chamber: mechanical boosting and turbo boosting. The power source for mechanical boosting is the power from the engine itself, resulting in a burden to the engine. The power source for turbo boosting uses the exhaust gas after combustion, which results in a lag in the operation (known as turbo lag).
An objective of the present invention is to provide an auxiliary intake device and an air intake system, allowing the engine to output higher power at higher speeds.
Another objective of the present invention is to provide an air intake system that allows instant boosting of the pressure in each cylinder of the engine.
In accordance with an aspect of the invention, an auxiliary intake device for an engine is provided and comprises a bypass tube and a control valve mounted on the bypass tube. The bypass tube includes a first end connected to an air cleaner and a second end connected to an intake tube at a position between an intake manifold and a throttle that is mounted in an intake tube between the air cleaner and the intake manifold. The control valve is closed when a speed of an engine is below a predetermined value. The control valve is opened when the speed of the engine is equal to or greater than the predetermined value, allowing additional air from the air cleaner to enter the manifold via the bypass tube and the control valve.
In accordance with another aspect of the invention, an air intake system for an engine is provided and comprises an air cleaner, an intake manifold, an intake tube mounted between the air cleaner and the intake manifold, a bypass tube including a first end connected to the air cleaner and a second end connected to the intake tube at a position between the intake manifold and a throttle mounted in the intake tube, and a control valve mounted on the bypass tube. The control valve is closed when a speed of an engine is below a predetermined value. The control valve is opened when the speed of the engine is equal to or greater than the predetermined value, allowing additional air from the air cleaner to enter the manifold via the bypass tube and the control valve.
The control valve may be an electromagnetic valve. A fan motor may be provided for driving air into the manifold. Preferably, the fan motor is mounted on the bypass tube.
Preferably, the control valve further includes an adjusting member for adjusting an amount of the additional air entering the manifold.
Preferably, a switch is connected between an accelerator pedal and the control valve. The switch is activated to open the control valve when the accelerator pedal is depressed through a predetermined distance. Preferably, a relay is mounted between the switch and the control valve and electrically connected to a power source. Alternatively, the switch is mounted adjacent to an accelerator rod. The switch is activated to open the control valve when the accelerator rod is moved through a predetermined distance.
Other objectives, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
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Adjustment of the adjusting member 226 of the control valve 22 allows the gap between the plug 222 of the stem 221 and the peripheral wall delimiting the inlet 211 of the coupler 21 to be adjusted, controlling the amount of fresh air passing through the inlet 211 of the coupler 21 and preventing intake of excessive additional fresh air.
The switch 3 may be activated by an accelerator rod (not shown) connected to and driven by the accelerator pedal 13. In other words, the control valve 22 is opened when the accelerator rod is moved through a predetermined distance.
Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the essence of the invention. The scope of the invention is limited by the accompanying claims.
