Abstract:
An apparatus and method for controlling a plurality of charge motion control devices in the air intake manifold. In a first aspect of the invention, the valves are controlled through a single common drive shaft. In a second aspect, the runners each include an air flow bypass positioned between the valve and the cylinder head mounting end of the runner such that the valve is positioned further away from the combustion chamber.

Description:
TECHNICAL FIELD 
     The present invention relates to flow control devices and methods in an internal combustion engine, and more particularly relates to a charge motion control device and method for improved control of air flow through the intake manifold of the engine. 
     BACKGROUND OF THE INVENTION 
     It is generally known in the art of internal combustion engine design to use charge motion control valves in an intake manifold. The “charge” is understood to mean the air-fuel mixture being delivered to the combustion chamber. “Charge motion” is a purposely induced, preferential movement of the charge for more efficient burning in the combustion chamber. There are basically two main types of induced charge motion: tumble and swirl. “Tumble” is understood to mean air turbulence about an axis perpendicular to the longitudinal axis of the cylinder. “Swirl” is air turbulence rotating about an axis generally parallel to the cylinder axis. Today&#39;s prevalent method for inducing tumble and/or swirl in an engine is through the use of valves that are configured to preferentially direct air flow through the intake runners and/or combustion chamber. The valves may be programmed to work during certain selected engine conditions to improve the homogeneity of the charge which will thus burn more effectively. For example, tumble is particularly desirable and effective during the first 20 seconds of a cold engine start and also at light engine load conditions (e.g., less than about 3,000 rpm). 
     Prior art tumble control valves generally comprise a valve body having an internal cavity and a valve flap or blade pivotally disposed within the internal cavity of the valve body. The valve blade pivots between fully open and fully closed positions. When in the fully closed position, the blade lies substantially perpendicular to the longitudinal axis of the valve body. In this position, the bottom edge of the blade lies in close relationship to the bottom wall of the internal cavity, thus effectively sealing off this area to air flow. Conversely, the top edge of the blade lies in spaced relation to the top wall of the internal cavity to define a gap wherethrough air may flow. Thus, in the fully closed position of the valve blade, maximum tumble is generated since the air flow is forced to pass through the gap defined along the top wall of the internal cavity of the valve body. When engine conditions indicate tumble or swirl are not needed, the valve opens to allow air flow through the runner in the normal manner. 
     The charge motion control valves are typically positioned in each air intake runner in close proximity to the inlet to the engine head port and intake valve. If the valves are located at too great a distance, the tumble or swirl effect is reduced or eliminated before the air intake charge enters the combustion chamber. In some applications, a shelf or flow divider is placed in the runner, just downstream of the charge motion valve, to extend the biased flow closer to the intake valve in the head. Because of the need to have the charge motion control valves close to the intake valve in the head, V6 and V8 applications of tumble and swirl control require two sets of valves, one set for the right bank and one set for the left bank of the engine. 
     A common actuator is usually employed to drive both sets of motion control valves. An exposed linkage extends from either side of the actuator to drive each of the two sets of valves. This linkage arrangement between the two sets of valves has drawbacks such as wear and breakage of the linkage parts, the added parts cost and space requirements within the engine compartment, for example. Although two shafts and associated linkages to the actuator are not required in a straight, in-line engine, the fact that the tumble control valves must be placed close to the cylinder heads places limitations on engine and manifold design and creates possible valve failure due to the high heat environment in the vicinity of the combustion chambers. It would therefore be desirable to have a design and method for controlling motion control valves of an engine which do not have the above-mentioned drawbacks of present day motion control valve drive arrangements. 
     SUMMARY OF THE INVENTION 
     The present invention successfully addresses the shortcomings of the prior art by providing in a first aspect of the invention a charge motion control device and method that utilizes a common drive shaft to drive both the right and left bank set of charge motion valves. In another aspect of the invention, a runner close-off valve is positioned in the runner with a runner bypass wherethrough air is directed when the valve is closed. Since the runner bypass induces the desired motion close to the cylinder head, the valve can be positioned further away from the high temperature environment of the combustion chamber. Although detailed description of the preferred embodiment herein will be directed to a V-type engine, it is understood that the invention is useful in both in-line and V-type engine designs. 
     The air intake manifold delivers air through individual runners, one for each cylinder head of the engine. Thus, in a V-6 engine for example, six individual runners extend to deliver air to the six cylinders of the engine, respectively. In the upper part of the manifold, the runners are arranged in linear fashion. At the lower part of the manifold, one half of the runners (three in the V-6 example) branch to the right bank of cylinder heads while the other half of runners branch to the left bank of cylinder heads of the engine. Since the charge motion control valves are positioned in the runners prior to the point where they branch off to the right and left cylinder banks, the valves may be controlled through a common drive shaft which greatly improves the overall manifold design as discussed above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is an exploded isometric view of an air intake manifold in accordance with an embodiment of the invention; and 
         FIG. 2  is a cross-sectional view as taken generally along the line  2 - 2  in  FIG. 1 , in the assembled condition. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, there is seen in  FIGS. 1 and 2  a preferred embodiment of the inventive charge motion control device incorporated into an air intake manifold assembly designated generally by the reference numeral  10 . It is understood that intake manifold assembly  10  is provided for purpose of description only and the invention is not limited to the particular manifold design shown in the figures. Rather, the invention is applicable to any manifold design which could benefit from the advantages the present invention offers as further explained below. 
     Referring to  FIG. 1 , an air intake manifold having a first or upper manifold portion  12  and a second or lower manifold portion  14  is provided to deliver air to the combustion chambers of an internal combustion engine (not shown). In the illustrated embodiment, the upper manifold  12  includes six upper manifold runners  16   a - 16   f  although the number of runners in the particular manifold design being employed will vary depending on the number of engine cylinders for which the manifold is designed. The upper manifold runners  16   a - 16   f  extend and receive air from a main air intake port  18 . 
     A valve flange  20  having six runner openings  20   a - 20   f  is mounted to upper manifold  12  with the valve flange runner openings  20   a - 20   f  in registration with upper manifold runners  16   a - 16   f , respectively. While valve flange  20  is shown as a separate part, it may be formed integral with upper or lower manifold  12 ,  14  as desired. 
     Lower manifold  14  includes an upper mounting plate  22  having six runner openings  22   a - 22   f  formed therein. During assembly of the upper and lower manifold portions  12  and  14 , lower manifold runner openings  22   a - 22   f  are placed in registration with valve plate openings  20   a - 20   f , and thus also upper runners  16   a - 16   f , respectively. Each respective set of openings  16   a - 16   f ,  20   a - 20   f , and  22   a - 22   f  is arranged in linear fashion. 
     At lower manifold portion  14 , runner openings  22   a - 22   f  extend into respective lower manifold runners  24   a - 24   f  which branch off in opposite, non-linear fashion so that three outlet ends  24   b ′,  24   d ′ and  24   f ′ thereof may be aligned with and mounted in registration with the left bank of cylinder heads of a V-6 engine (not shown) while the other three outlet ends  24   a ′,  24   c ′ and  24   e ′ thereof may be aligned with and mounted in registration with the right bank of cylinder heads. In the preferred embodiment, lower manifold runners  24   a - 24   f  alternately branch away in different directions although this may vary as desired. As stated above, a V-6 engine application is only an exemplary embodiment of the invention and the particular number and arrangement of runners will depend on the engine for which the manifold is designed. 
     Six charge motion control valves  26   a - 26   f  which optionally include respective seals  40   a - 40   f  are positioned at or near lower manifold runner openings  22   a - 22   f , respectively. Since lower manifold openings  22   a - 22   f  are arranged in linear fashion as described above, motion control valves  26   a - 26   f  are likewise arranged in linear fashion. As such, a single drive shaft  28  may extend through and control movement of all six valves  26   a - 26   f . Drive shaft  28  is driven by a single actuator  30  via coupling  31  with no linkages being required as in the prior art where two separate drive shafts, one for each cylinder bank, are required and driven by a common actuator as explained above. Although the preferred embodiment herein described and shown does not include linkages between the actuator and drive shaft, it is possible that a simple linkage may be required if the actuator must be placed offset from the drive shaft. Such offsetting of the actuator with respect to the drive shaft may be necessary in some engine compartment designs. 
     As stated above, lower manifold  14  openings  22   a - 22   f  are arranged in linear fashion with lower manifold runners  24   a - 24   f  alternately branching in opposite direction to align with the right and left backs of cylinder heads. Thus, lower manifold  14  openings  22   a - 22   f  feed both the right and left banks of the cylinder heads. Since the motion control valves  26   a - 26   f  are placed at the linearly arranged openings  22   a - 22   f , they also are arranged in linear fashion allowing them to be driven by a single drive shaft  28 . 
     Two of the alternately branching lower manifold runners are seen best in the cross-sectional view of  FIG. 2 . In  FIG. 2 , it is seen that lower manifold runners  24   e  and  24   f  each include a respective runner bypass  32   e  and  32   f . While description of the bypass runners herein relate particularly to runner  24   f , it is understood that each lower manifold runner  24   a - 24   f  has such a runner bypass. 
     The upper inlet end of each runner bypass  32   f ′ is positioned radially outwardly of the peripheral edge  26   f ′ of the respective motion control valve blade  26   f  when the valve  26   f  is in the closed position as seen in  FIG. 2 . When the valve is in this closed position, it extends in a plane substantially perpendicular to its respective runner (valve  26   f  and respective runner  22   f  seen in  FIG. 2 ) and thus blocks airflow through the corresponding lower manifold runner  24   f . Hence, air is diverted through the respective bypass  32   f ′ which is outboard of and thus not blocked by the closed valve blade  26   f ′. Although the closed valve  26   f  is illustrated in the preferred embodiment as substantially completely blocking air from flowing through lower manifold runner  24   f , it is understood that the valve geometry for a particular application may allow some air to pass through the runner even when the valve is completely closed. 
     The outlet end  32   f ′ of the runner bypass  32   f  is positioned and shaped to induce a preferred motion to the air flow as it enters lower manifold runner  24   f . In the preferred embodiment, the bypass outlet end is positioned close to one side of the respective lower manifold runner  24   f  preferably near the cylinder head mounting end  24   f ′ thereof. As such, tumble is induced in the lower manifold runner  24   f  in a position very close to the respective cylinder head. As explained above, it is desirable to induce tumble or swirl as close to the cylinder head as possible. 
     Alternate embodiments may position the bypass outlet end closer to or even directly at the center of the runner so long as the intended and preferred motion to the air flow is induced. For example, charge motion may be induced simply by orienting the outlet end to direct air in a direction transverse to the longitudinal extent of the runner, regardless of radial position of the outlet within the runner. 
     The engine control system (not shown) operates actuator  30  to move shaft  28  and thus also charge motion control valves  26   a - 26   f  in accordance with engine load conditions. When the system determines a charge motion such as tumble or swirl is required, actuator  30  drives shaft  28  to close the charge motion control valves  26   a - 26   f . As such, air is diverted through the bypasses  32   a - 32   f  in each lower manifold runner and motion such as tumble or swirl is induced to the charge. When the valves are open, air may continue to flow through the bypasses in addition to the lower manifold runners, however, this would not induce appreciable tumble or swirl since the air movement is not biased away from linearly following the longitudinal extent of the runner. If desired, another valve could be placed to close off the bypass during times when the charge motion control valve is open. The induced charge motion may of course be modified and fine-tuned to particular application requirements by changing the position and/or geometry of the bypass and/or respective runner. For example, various velocity and charge motion profiles can be designed through appropriate selection of bypass and manifold runner diameters and geometries. Such design selections and modifications are well within the abilities of those skilled in the art. 
     While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.