Description of the Related Art Air intake manifolds for internal combustion engines are used to transport and direct air and fuel to the cylinders of the internal combustion engine. The intake manifold receives the air from a plenum. Once the air leaves the plenum, the manifold directs the air to the individual cylinders where it is received and used in combustion.

The geometry of each of the runners in the intake manifold dictate how efficient the transportation of the air to the cylinders of the internal combustion engine is. The length and the cross-sectional area of the runners directly affect the pressure and velocity at which the air reaches the cylinders.

The design of the runner is typically made to optimize the performance of the internal combustion engine at a specific speed thereof. While optimization occurs at a specific speed, compromises in performance are made at every other speed in which the internal combustion engine operates. Therefore, there is a need to successfully control the pressure and velocity of the air as it passes through the runners of the intake manifold allowing optimization of the internal combustion engine performance at a plurality of speeds.

United States Patent 4,210, 107, issued to Shaffer on July 1,1980, discloses a tunable intake manifold. The intake manifold includes a plurality of intake runners, each having a side wall that is adjustable throughout the length of each of the intake runners. The adjustable side walls move transversely inwardly and outwardly with respect to the flow direction of the air throughout the intake runner to correspondingly decrease and increase the through flow cross-sectional area. While such an adjustable side wall may adjust the cross-sectional area of each of the runners, the side wall creates a space between the side wall and the side of the runner that the side wall has

moved away from. This unused volume is not sealed and may receive portions of the air as it passes thereby, which will reduce the effectiveness of the device and create inefficiencies in the intake runners. In addition, these spaces may induce unwanted turbulence in the intake runners.

Summary Of The Invention According to one aspect of the invention, a tunable intake manifold is provided for directing a flow of air between a plenum and an internal combustion engine. The tunable intake manifold includes a manifold housing defining an interior.

The manifold housing has a plurality of runner walls extending through the interior.

The tunable intake manifold also includes a slider having a plurality of slider walls extending through the interior of the manifold housing. The plurality of slider walls corresponds to the plurality of runner walls to define a plurality of runners. Each of the plurality of runners has a defined cross sectional area for transporting the flow of air therethrough. The slider is slidably engaged with the manifold housing for moving the plurality of slider walls relative to the plurality of runner walls to selectively change the defined cross sectional area of the plurality of runners, such that the volume of air passing therethrough changes with the movement of the slider.

Brief Description Of The Drawings Advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: Figure 1 is a cut-away perspective view of a plenum and tunable intake manifold incorporating one embodiment of the invention; Figure 2 is a perspective view of the plenum and intake manifold; Figure 3 is an end view of the intake manifold; Figure 4 is a cut-away perspective view of the intake manifold with a portion of a manifold housing removed therefrom; and

Figure 5 is a cut-away perspective view of an alternative embodiment of the intake manifold with a portion of the manifold housing removed therefrom.

Detailed Description Of The Preferred Embodiments Referring to Figures 1 through 4, a tunable intake manifold is generally indicated at 10. The tunable intake manifold 10 extends between a receiving end 12 and a transmitting end 14. The transmitting end 14 includes an end plate 15 that defines a plurality of ports 17 corresponding to the cross section of a fully open runner, discussed in greater detail subsequently. The tunable intake manifold 10 includes a manifold housing 16 that extends between the receiving end 12 and the transmitting end 14. The manifold housing 16 defines an interior 18 and a plurality of runner walls 20 extending through the interior 18.

The tunable intake manifold 10 receives air from a plenum 21 that is fixedly secured to the receiving end 12 of the tunable intake manifold 10. The plenum 21 includes an inner cavity 21a that is used as a reservoir for air. The plenum 21 also includes a plurality of outlets 23 adjacent the receiving end 12 of the housing 16 and each generally corresponding to each of the opposing plurality of ports 17. While it is contemplated that the tunable intake manifold 10 is used with an internal combustion engine that incorporates fuel injection, it should be appreciated by those skilled in the art that the plenum 21 may hold an air/fuel mixture should the internal combustion engine be fitted with a carburetor or central fuel injector to transmit fuel for combustion.

The air is transmitted through the tunable intake manifold 10 for subsequent combustion in an internal combustion engine operatively connected to the transmitting end 14 of the tunable intake manifold 10. It should be appreciated that while the tunable intake manifold 10 is configured to work in conjunction with an I-4 internal combustion engine, the tunable intake manifold 10 may be designed to work cooperatively with any internal combustion engine configuration having any number of cylinders.

The tunable intake manifold 10 also includes a slider 22 that extends through the interior 18 of the manifold housing 16. The slider 22 slidingly engages the manifold housing 16 for transverse movement within the interior 18. The slider 22

includes a platform 24 that abuts against an interior surface 26 of the manifold housing 16. The interior surface 26 is longer than the platform 24 allowing the platform 24 to slide with respect to the interior surface 26.

The slider 22 also includes a plurality of slider walls 28. Each of the plurality of slider walls 28 is paired with each of the plurality of runner walls 20. The plurality of runner 20 and slider walls 28 cooperate with each other to define a plurality of runners 30. The plurality of runners 30 extend between the respective plurality of ports 17 and plenum outlets 23. Each of the runners 30 defines a defined cross- sectional area and volume. It is through the runners 30 that the air is transported from the plenum 21 to the internal combustion engine. As best shown in Figure 3, each of the plurality of runner walls 20 and plurality of slider walls 28 includes a curved end 31,33. Each of the plurality of runner walls 20 and plurality of slider walls 28 includes a lateral surface 32,34 that extends transversely from the curved end 31,33.

The curved ends 31,33 of the plurality of runner walls 20 and slider walls 28 cooperate with the lateral surfaces 34,32 of the plurality of slider walls 28 and runner walls 20, respectively, to define a plurality of openings 37 through which the flow of air enters each of the plurality of runners 30. The size of the plurality of openings 37 contracts and expands with corresponding transverse movement of the plurality of slider walls relative to the plurality of runner walls. The curved ends 31,33 and the lateral surfaces 32,34 are lip-shaped to maximize the efficiency of the air passing therethrough by minimizing flow losses.

To ensure unwanted cavities are not created, the slider 22 includes a plurality of end walls 35 that extend generally perpendicularly between the platform 24 and each of the plurality of slider walls 28. The end walls 35 close each of the plurality of ports 17 and each of the plurality of outlets 23 as the slider 22 moves to reduce the volume of the runners 30. It should be appreciated by those skilled in the art that the slider 22 can be formed of a single piece or it can be formed from a plurality of pieces fixedly secured together.

As best shown in Figure 4, a seal 36 extends along a runner distal end 38 for sealing the runner walls 20 against the platform 24 of the slider 22. Likewise, a seal 40 extends along a slider distal end 42 to seal each of the slider walls 28 against a second interior surface 44 of the manifold housing 16. Therefore, the runners 30 are

sealed channels through which the air is transported from the plenum 21 to the internal combustion engine. Preferably, the seal 36,40 is made from an elastomeric or polymeric material. The seal 36,40 may be fixedly secured to the distal end 38,42 by any suitable means, such as adhesives or interference fit. The seal 36,40 may also be integrally formed onto the distal end 38,42.

The tunable intake manifold 10 includes a drive assembly, generally shown at 46. The drive assembly 46 is fixedly secured to the manifold housing 16 and is operatively connected to the slider 22 to move the slider 22 transversely along the manifold housing 16 to change the defined cross section thereof. Changing the defined cross section of each of the plurality of runners 30 changes the volume of air passing therethrough. Because the slider 22 is infinitely adjustable along the interior surface of the manifold housing 16, an infinite number of adjustments may be made to the size of the runners 30 allowing optimization of volumetric efficiency in the transport of air to the internal combustion engine. This allows optimization over any speed at which the internal combustion engine is operating.

The drive assembly 46 includes an electronic actuator 48 and a drive screw 50.

The drive screw 50 is a worm gear that rotates with respect to the slider 22.

In the preferred embodiment, the electronic actuator 48 is a motor that receives signals based on the speed of the internal combustion engine and rotates the drive screw 50 accordingly to move the slider 22 to the proper location to maximize the volumetric efficiency of the internal combustion engine. The drive screw 50 engages a driven wall 52 that extends out from the platform 24 of the slider 22 perpendicularly thereto. The driven wall 52 includes a threaded aperture 54. The drive screw 50 threadingly engages the threaded aperture 54, such that the slider 22 moves relative to the manifold housing 16 in response to rotation of the drive screw 50.

By restricting and expanding the volume of the runners 30 using the tunable intake manifold 10, the volumetric efficiency of the internal combustion engine may be maximized or controlled over the entire range of engine speeds. By adjusting the cross section of the plurality of runners 30 by movement of the slider 22 instead of varying the runner length, the tuneable intake manifold 10 of the invention improves over conventional adjustable manifolds by having no increased frictional losses due to

increased wall length. The tunable intake manifold 10 is compact in size and simple in construction. Because the length of the runners 30 does not change, the tunable intake manifold 10 retains its compact size throughout its performance range.

Further, the tunable intake manifold 10 can be used to maximize the beneficial effects of the reflected suction wave created by the drawing of the piston down into the cylinder of the internal combustion engine. The tunable intake manifold 10 also permits optimization of the velocity of the flow of air entering the internal combustion engine. By doing so, the inertial supercharging of the internal combustion engine can be enhanced.

Referring to Figure 5, an alternative embodiment of the drive assembly 46'is shown, wherein a slider extension 60 protrudes outwardly from the platform 24'. The slider extension 60 includes an aperture 62. The drive screw 50'threadingly engages the aperture 62, such that the slider 22'moves relative to the manifold housing 16'in response to rotation of the drive screw 50'. The drive screw 50'is rotatably drive by the motor 48'.

It should be appreciated by those skilled in the art that the invention 10 could alternatively include any number of motors for moving the slider 22 relative to the manifold housing 16.

The invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.