Patent Grant
6976464
The present invention relates to a valve assembly suitable for use with an internal combustion engine, and more specifically, a semi-rotating valve assembly configured to reduce the consumption of fuel and the emission of pollutants.
Most modern internal combustion engines utilize a four stroke operating sequence known as the Otto cycle. The Otto cycle comprises an intake stroke, in which an intake valve opens and a mixture of air and fuel is directed into the cylinder of the engine. A compression stroke then occurs in which the piston compresses the mixture of fuel and air to increase the pressure in the cylinder. A spark provided by a spark plug ignites the mixture just before the piston reaches the top of the cylinder, causing the piston to be forced down the cylinder in the power stroke. An exhaust valve then opens in the exhaust stroke, in which burned gases are forced out of the cylinder. The four strokes are repeated continuously during operation of the engine.
Internal combustion engines operating on the Otto cycle generally utilize spring-loaded poppet valves that selectively open and close the intake and exhaust ports during each cycle. In most engines, a crankshaft is coupled to a timing belt or chain, which in turn is coupled to a camshaft that rotates to open the intake and exhaust valves during the intake and exhaust strokes, respectively. A spring associated with each valve closes the valve during the other cycles.
There are several drawbacks associated with the use of such spring-loaded poppet valves. One drawback is that the valves protrude into the cylinder during each cycle, and there is an inherent risk that the piston may contact an open valve at a high force and cause substantial engine damage. Additionally, valve timing events may be limited due to the protrusion of the valve head into the cylinder.
Another disadvantage with the use of poppet valves in conventional internal combustion engines is that a relatively stiff spring is used to close the valves. Therefore, a relatively strong force is required to overcome the resistive force of the spring to open each valve during each cycle, reducing the efficiency of the engine. Moreover, due to the stiff resistive force provided by the springs, valve timing events may be limited. For example, there generally is a short time period during which both the intake valve and the exhaust valve are open when conventional poppet valves and stiff springs are employed. During this overlap period, unburned hydrocarbon molecules may remain in the combustion chamber for a subsequent cycle, thereby adversely affecting dynamic compression and reducing engine efficiency.
Yet a further disadvantage associated with the use of conventional poppet valves is that energy is lost as a result of an obstruction of the orifice, i.e., because a portion of a poppet valve protrudes through the orifice and into the cylinder. Moreover, flow into the cylinder through the intake port is disrupted when it contacts the head of the poppet valve, i.e., the portion of the valve that seals the orifice in the closed state. The intake valve head may cause turbulence and dead air space within the cylinder, which in turn reduces the efficiency of the engine. Furthermore, when the head of the exhaust valve protrudes into the cylinder during the exhaust stroke, burned gases may not efficiently flow out of the cylinder, which further reduces combustion capabilities.
Various rotational valve designs, which may be used in conjunction with internal combustion engines, have been developed that seek to overcome several of the drawbacks associated with conventional poppet valves. One primary advantage of a rotational valve assembly is the capability to have a substantially unobstructed flow path through a port of a rotating valve. Specifically, because a conventional poppet valve is not employed, and therefore does not obstruct the flow path through an intake or exhaust port, a rotational valve has the potential to significantly increase airflow capability into a cylinder. Moreover, since the stiff spring used in conjunction with conventional poppet valves may be omitted, rotational valve assemblies may achieve reduced mechanical loads.
Previous rotary valve assemblies have included rotating discs, cylinders, sleeves and other spheroidal rotating mechanisms. Such previously known rotational valves rotate a full 360 degrees and are timed such that their apertures overlap with the cylinder during the intake and exhaust strokes. However, due to their 360 degree rotation and continuous motion, such fully rotational valves may experience high temperatures and extreme friction, resulting in high rates of wear imposed on the valve and any related sealing mechanisms.
Moreover, such fully rotational valves generally have fixed aperture sizes, i.e., the size of the aperture in registration with the cylinder may not be varied as the valve rotates. Accordingly, fuel consumption and emissions may be increased by providing a relatively large aperture, particularly during idling conditions.
U.S. Pat. No. 4,944,261 to Coates describes a rotary valve assembly for use in an internal combustion engine. The assembly comprises a two-piece cylinder head that accommodates rotary intake valves and rotary exhaust valves mounted on independent shafts. Each intake valve has two passageways for the introduction and interruption of fuel/air mixture into the cylinder, and each exhaust valve has two passageways for the evacuation and interruption of spent gases from the cylinder.
As the intake valve shaft rotates a full 360 degrees, as driven by a crankshaft, the passageways of the intake valves are selectively placed in registration with the cylinder during intake strokes only. Similarly, the passageways of the exhaust valves are placed in registration with the cylinder during exhaust strokes only. At all other times of rotation, fluid communication is inhibited. By using two passageways on each valve, and by employing independent shafts, the Coates patent states that the valves rotate at a one-quarter speed in relationship to the crankshaft, thereby reducing overall wear on the valves and enabling cooler operating temperatures.
One drawback associated with the rotary valve system described in the Coates patent is that each intake and exhaust valve is fully rotational, i.e., each valve rotates continuously 360 degrees. Accordingly, even though the valves rotate at a one-quarter speed in relationship to the crankshaft, the continuous motion of the valves is still expected to result in relatively high levels of friction, heat and wear.
Moreover, because the valves described in the Coates patent are continuously rotating, the size of the aperture in registration with the cylinder may not be varied. Specifically, while the rotational speed of the valves may be varied in response to the crankshaft rotation, the actual aperture size of the valves remains fixed. It would be advantageous to provide a mechanism configured to vary the aperture size to further improve efficiency at a variety of engine speeds.
Furthermore, while the spherical rotary valve assembly described in the Coates patent may be actuated using a plurality of gears, the assembly does not appear to be easily adaptable for use with other means for actuating, for example, camshafts, solenoids, and other mechanisms. The capability to employ such other means for actuating may afford more design flexibility.
U.S. Pat. No. 6,308,677 to Bohach et al. (Bohach) describes an overhead rotary valve assembly fitted into a cylinder head of an internal combustion engine. The rotary valve comprises diametrical polygonal openings formed therein to bring intake and exhaust ports into and out of alignment with passages leading to and from the combustion chamber. Sprockets that are mechanically driven by the crankshaft are employed to cause the rotary valve assembly to rotate continuously in a 360 degree motion.
The rotary valve system described in the Bohach patent has several drawbacks, many of which are similar to drawbacks described hereinabove with respect to the Coates patent. Specifically, the rotary valve system of the Bohach patent is fully rotational, i.e., rotates continuously 360 degrees. The continuous motion of the valve is expected to result in relatively high levels of friction, heat and wear. Additionally, because the valve described in the Bohach patent is continuously rotating, the size of the aperture in registration with the cylinder may not be varied, as described hereinabove with respect to the Coates patent. Finally, while the rotary valve system described in the Bohach patent is actuated using a plurality of sprockets operatively coupled to the crankshaft, the assembly does not appear to be easily adaptable for use with other means for actuating, such as camshafts, solenoids, etc., which may afford more design flexibility.
Another rotary valve system is described in U.S. Pat. No. 6,293,242 to Kutlucinar. The Kutlucinar patent describes a rotary valve assembly having an elongated valve body mounted in a housing positioned above a head port of an engine. The rotary valve includes an intake port and an exhaust port defined by a valve body, and is arranged for periodic communication with the head port and combustion chamber as the valve rotates. The rotary valve system also includes a secondary intake port for controlling the flow of intake gases into the rotary valve.
The Kutlucinar patent also discloses a sealing system intended to seal the rotary valve in the longitudinal and radial directions. In operation, the sealing elements mounted on the rotary valve dynamically change position depending on the stage of the combustion cycle, for example, the sealing system is configured to form a tighter seal during the combustion stage than during the intake stage.
Additionally, the Kutlucinar patent discloses a throttle control for the rotary valve that has a sliding throttle plate configured to vary the effective size of the intake port opening to compensate for differences in engine speed. The sliding throttle plate may move back and forth in a longitudinal direction within the rotary valve, such that the longitudinal movement of the sliding throttle plate may cover the intake port different amounts at different engine speeds.
The rotary valve system described in the Kutlucinar patent also has several drawbacks, many of which are similar to drawbacks described hereinabove with respect to the Coates and Bohach patents. In particular, the rotary valve system of the Kutlucinar patent is fully rotational, i.e., rotates continuously 360 degrees. The continuous motion of the valve is still expected to result in relatively high levels of friction, heat and wear, despite the fact that a cooling system is employed. Additionally, because the rotary valve system described in the Kutlucinar patent is actuated using a plurality of gears operatively coupled to the crankshaft, like the above-referenced patents, the assembly does not appear to be easily adaptable for use with other means for actuating that may afford more design flexibility.
Another drawback associated with the Kutlucinar patent is the complexity of the sealing system. Specifically, the sealing system employs a significant number of seals, particularly small seals, as depicted in
In view of these drawbacks of previously known systems, it would be desirable to provide apparatus and methods for a semi-rotating valve assembly that is configured to be easily incorporated into existing internal combustion engine designs.
It also would be desirable to provide apparatus and methods for a semi-rotating valve assembly that improves fuel efficiency relative to known fully rotating valve assemblies.
It further would be desirable to provide apparatus and methods for a semi-rotating valve assembly that reduces the emission of pollutants.
It still further would be desirable to provide apparatus and methods for a semi-rotating valve assembly that improves horsepower and torque.
It still further would be desirable to provide apparatus and methods for a semi-rotating valve body that is configured to rotate less than 360 degrees with respect to a valve housing, thereby reducing friction, heat and wear on the valve body and related sealing components.
It yet further would be desirable to provide apparatus and methods for a semi-rotating valve assembly having an improved sealing assembly configured to effectively seal the valve in radial and longitudinal directions.
It still further would be desirable to provide apparatus and methods for a semi-rotating valve assembly having a means for cooling configured to further reduce valve temperatures and exhaust emissions.
It yet further would be desirable to provide apparatus and methods for a semi-rotating valve assembly that may be actuated using any number of means for actuating to afford more design flexibility.
It still further would be desirable to provide apparatus and methods for a semi-rotating valve assembly that may be used in conjunction with means for varying an aperture size associated with the valve, the means for varying compensating for differences in engine speed to improve engine efficiency and reduce fuel consumption and emissions.
In view of the foregoing, it is an object of the present invention to provide apparatus and methods for a semi-rotating valve assembly that is configured to be easily incorporated into existing internal combustion engine designs.
It is also an object of the present invention to provide apparatus and methods for a semi-rotating valve assembly that improves fuel efficiency relative to known fully rotating valve assemblies.
It is a further object of the present invention to provide apparatus and methods for a semi-rotating valve assembly that reduces the emission of pollutants.
It is yet another object of the present invention to provide apparatus and methods for a semi-rotating valve body that is configured to rotate less than 360 degrees with respect to a valve housing, thereby reducing friction, heat and wear on the valve and body related sealing components.
It is still another object of the present invention to provide apparatus and methods for a semi-rotating valve assembly having an improved sealing assembly configured to effectively seal the valve in radial and longitudinal directions.
It is yet another object of the present invention to provide apparatus and methods for a semi-rotating valve assembly having a means for cooling configured to further reduce valve temperatures and exhaust emissions.
It is yet another object of the present invention to provide apparatus and methods for a semi-rotating valve assembly that may be actuated using any number of means for actuating to afford more design flexibility.
It is still a further object of the present invention to provide apparatus and methods for a semi-rotating valve assembly that may be used in conjunction with means for varying an aperture size associated with the valve, the means for varying compensating for differences in engine speed to improve engine efficiency and reduce fuel consumption and emissions.
These and other objects of the present invention are accomplished by providing a valve body having a substantially cylindrical shape, and further having a first side port disposed in a first lateral surface of the valve body and a second side port disposed in a second lateral surface of the valve body. A passage extends between the first side port and the second side port to allow fluid communication therebetween.
The valve body is disposed substantially within a cylindrically-shaped bore of a valve housing. The valve body is configured to rotate less than 360 degrees with respect to the valve housing, thereby selectively enabling and prohibiting fluid communication between the passage of the valve body and a cylinder of an internal combustion engine. Specifically, partial rotation of the valve body in a first direction enables fluid communication, while partial rotation of the valve body in an opposing direction inhibits fluid communication with the cylinder.
Advantageously, because the valve body rotates less than 360 degrees with respect to the valve housing, friction, heat and wear on the valve body and related sealing components may be reduced compared to known fully rotational valves. Moreover, because a valve body provided in accordance with the present invention may dwell when not in use, e.g., an intake valve body does not substantially move during the compression, power and exhaust strokes, friction, heat and wear is further reduced.
Means for actuating a semi-rotating valve, provided in accordance with the present invention, also are provided. Any number of means for actuating may be employed to cause partial rotation of the valve body. For example, camshafts, solenoids, rocker arms, chains, gears, belts, hydraulics, pneumatics, electric actuators, and/or other means may be employed to cause partial rotation of the valve body. Advantageously, the present invention allows considerable flexibility with respect to the number of different means for actuating that may be employed, particularly compared to prior art rotational valve assemblies that rely solely on gearing mechanisms to provide rotation of the valve. Such design flexibility provides various advantages, for example, partial rotation of the valve body and the attainment of variable aperture sizes and timing events, as generally described hereinbelow.
In accordance with another aspect of the present invention, an interlocking sealing mechanism is used in conjunction with the semi-rotating valve of the present invention. The interlocking sealing mechanism comprises a plurality of interlocking components configured to seal the valve assembly in both radial and longitudinal directions. Several of the components have tapered portions configured to mate with other tapered components. Other sealing components are configured to be seated within cavities of other components, thereby providing an interlocking feature that enhances sealing capabilities. Moreover, the interlocking sealing mechanism of the present invention employs relatively few seals compared to known sealing mechanisms.
In a preferred embodiment, the semi-rotating valve assembly of the present invention further comprises at least one cooling passage disposed in a valve body substantially adjacent to the valve housing. The cooling passages preferably at least partially surround the valve housing, and are configured to carry heat away from the valve bodies by circulating coolant through the passages. Advantageously, when such cooling passages are used in conjunction with an exhaust valve, cooler exhaust temperatures and lower NOx emissions may be achieved.
In a preferred embodiment of the present invention, means for varying an aperture size associated with the semi-rotating valve of the present invention also are employed. The means for varying is configured to vary the aperture size by varying a degree of rotation of the semi-rotating valve based on operating conditions. For example, the means for varying an aperture size may increase aperture size associated with the valve during an acceleration period, and may reduce aperture size during idling conditions, thereby improving engine efficiency and reducing fuel consumption and emissions.
Apparatus and methods for using a semi-rotating valve assembly in conjunction with a conventional internal combustion engine, whereby a first semi-rotating valve of the present invention is employed as an intake valve, and a second semi-rotating valve is employed as an exhaust valve, also are provided.
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments, in which:
Referring now to
In
Referring still to
As depicted in
Side seals 36a–36c preferably comprise tapered ends 43, as depicted in
The interlocking sealing mechanism of semi-rotating valve 20 further preferably comprises lock ring seals 50 and tapered seals 54. Each lock ring seal 50 is configured to be seated in recess 59 of tapered seal 54. Each lock ring seal 50 comprises cavities 51a–51c, which correspond to grooves 35a–35c of valve body 30. Accordingly, end regions of side seals 36a–36c may be seated within cavities 51a–51c of lock ring seals 50 when valve 20 is assembled, as shown in
In the assembled state, first and second bearings 60 are configured to be seated within respective bearing housings 65 formed in end seals 64a and 64b, as shown in
End seal 64a comprises back wall 68, while end seal 64b comprises a back wall having central bore 69, as shown in
Valve shaft region 34a of valve body 30 preferably has a shorter longitudinal length than valve shaft region 34b. Accordingly, valve shaft region 34a is configured to be disposed through lock ring seal 50, central bore 58 of tapered seal 54 and central bore 62 of bearing 60. Valve shaft region 34a does not extend fully through end seal 64a, but rather abuts back wall 68 of end seal 64a, as shown in
Each tapered seal 54 comprises tapered edge 57, which is configured to sealingly engage tapered rings 66 of end seals 64a and 64b in the assembled state (see
In a preferred embodiment, first and second circular springs 47 are disposed over valve shaft regions 34a and 34b, as depicted in
As described hereinabove, the interlocking sealing mechanism of semi-rotating valve 20 is configured to seal the valve assembly in both radial and longitudinal directions. Advantageously, the interlocking sealing mechanism employs relatively few seal components, relative to previously known sealing mechanisms. Moreover, it is expected that the interlocking characteristics of the seals, including the manner in which various tapered regions mate together, is expected to further improve sealing capabilities during operation.
Referring now to
In
In a preferred embodiment of the present invention, valve body 92 comprises first cylindrically-shaped bore 94 that defines intake valve housing 93, as shown in
Referring still to
Valve body 92 further preferably comprises intake port 96 and exhaust port 196, which preferably are formed as holes bored into valve body 92, as depicted in
As will be described in greater detail hereinbelow with respect to
Referring still to
In
At this time, a mixture of air and fuel may be directed into combustion chamber 82 of engine 80 via intake passage 95, passage 76, and intake bore 96. As will be apparent to one skilled in the art, fuel alternatively may be directly injected into combustion chamber 82 using a direct fuel injection port (not shown), while air is still provided via intake passage 95, passage 76, and intake bore 96.
As will be described hereinbelow with respect to
During the intake stroke of engine 80, exhaust valve 120 is provided in a closed state, whereby first side port 131 of exhaust valve body 130 does not overlap with exhaust passage 195, and second side port 132 of exhaust valve body 130 does not overlap with exhaust port 196, as shown in
Referring now to
In the closed state, intake valve body 30 is positioned such that first side port 31 does not overlap with intake passage 95, and second side port 32 does not overlap with intake port 96, thereby inhibiting fluid communication between combustion chamber 82 and intake passage 95, as depicted in
To close intake valve 20, intake valve body 30 is rotated in a direction that is the opposite direction used to open intake valve 20. For example, if a clockwise rotation of less than 360 degrees is used to open the valve, as depicted in
Referring still to
After the power stroke, an exhaust stroke occurs whereby the means for actuating employed causes exhaust valve body 130 to be partially rotated with respect to exhaust valve housing 193, thereby forcing burned gases out of cylinder 81. The exhaust stroke of engine 80 is depicted in
Advantageously, in accordance with one object of the present invention, the use of semi-rotating intake and exhaust valves is expected to significantly reduce friction, heat and wear imposed on the intake and exhaust valves, as well as related sealing components. This is primarily because the valve bodies are configured to rotate less than 360 degrees with respect to their respective valve housings. As depicted in
Additionally, in accordance with another object of the present invention, the interlocking sealing mechanisms of intake valve 20 and exhaust valve 120 are expected to provide improved sealing capabilities during operation. For example, when there is an increased pressure in the combustion chamber, the interlocking components form a tight seal to prevent leakage in both radial and longitudinal directions, in part due to the manner in which various tapered regions mate together. Because the interlocking sealing mechanisms form a tight seal, power and efficiency may be improved, while emissions may be reduced. Moreover, the interlocking sealing mechanisms may be configured to assume relaxed states when significant pressures from the combustion chamber are no longer imposed, thereby further reducing rates of wear.
Referring now to
In a preferred embodiment of the present invention, wear sleeve 78 is disposed between valve body 30 of
In
Block 92 further comprises spark plug housing 89, as shown in
Referring still to
In operation, a suitable coolant may be circulated through intake cooling passages 71a–71c, and similarly through exhaust cooling passages 171a–171c. Coolant may be continuously recirculated through the cooling passages during operation of engine 80. Advantageously, circulation of coolant through cooling passages 71a–71c and 171a–171c is expected to carry considerable heat away from intake valve body 30 and exhaust valve body 130, respectively. Furthermore, the provision of cooling passages 171a–171c is expected to facilitate cooler exhaust temperatures and, therefore, lower NOx emissions may be achieved.
It will be apparent to one skilled in the art that, while three cooling passages are depicted partially surrounding each valve housing, greater or fewer cooling passages may be employed. Also, the circulation capacity of the cooling passages, along with the speed of circulation, may vary with various engine design requirements, such as displacement, compression ratio and aspiration.
Furthermore, the configuration of cooling passages 71a–71c may be varied, for example, cooling passage 71a may be provided with reduced area section 72a to permit circulation of coolant around intake passage 95. It will be apparent to one skilled in the art that the exact positioning of the cooling passages within valve body 92 may be varied to accommodate various design requirements.
Referring now to
In the embodiment of
As depicted in
In a preferred embodiment, the first set of actuation components used to actuate intake valve 20 is identical to the second set of actuation components used to actuate exhaust valve 120. Moreover, actuation of intake valve 20 occurs in a manner substantially identical to actuation of exhaust valve 120. Therefore, in
Finally, it should be noted that, in the embodiments of
Referring back to
The first end of rocker arm 110a is coupled to cam follower 106 via pin 113, while the second end of rocker arm 110a is coupled to connecting rod 111a via pin 114, as shown in
In a preferred embodiment, connecting rod 111a is operatively coupled to valve shaft region 34b of intake valve 20 via connecting link 74. Preferably, connecting link 74 is coupled to connecting rod 111a using pin 75, as shown in
In the schematic of
The second end of rocker arm 110a, which is coupled to connecting rod 111a, translates a downward movement to connecting rod 111a. Downward movement of connecting rod 111a causes a partial rotation of intake valve body 30 via connecting link 74 and pin 75. The partial rotation of intake valve body 30 causes first side port 31 of intake valve body 30 to at least partially overlap with intake passage 95 of valve body 92, as shown in
Referring now to
The second end of rocker arm 110b, which is coupled to connecting rod 111b, translates a downward motion to connecting rod 111b, which in turn actuates exhaust valve body 130. Exhaust valve shaft 130 is partially rotated to cause first side port 131 to at least partially overlap with exhaust passage 195 of valve body 92, as shown in
During the exhaust stroke, depicted in
As described in
It will be understood by one skilled in the art that fewer or greater parts may be employed to achieve the actuation results described in
Referring now to
The first rocker arm 210, which is coupled to intake valve 20, has first and second ends and a bore (not shown) that extends laterally through the rocker arm. The bore has a diameter that is slightly larger than an outer diameter of rocker arm shaft 102, thereby allowing rocker arm 210 to be moveably disposed on rocker arm shaft 102.
Alternative actuation assembly 100′ further comprises first sprocket 204 and second sprocket 208. Linkage 207, for example, a chain or belt, is coupled between first and second sprockets 204 and 208. As will be understood by one skilled in the art, first and second sprockets 204 and 208 have a plurality of teeth configured to engage a plurality of perforations of linkage 207, such that rotational motion of first sprocket 204 is translated into rotational motion of second sprocket 208.
Sprocket support member 212, which preferably is disposed atop valve body 92, comprises sprocket support rod 206 extending therefrom. A central bore of first sprocket 204 is disposed through sprocket support rod 206, thereby allowing first sprocket 204 to rotate on the sprocket support rod. Second sprocket 208 may be directly coupled to valve shaft region 34b of intake valve 20, as shown in
Rocker arm 210 comprises slot 211, which is disposed through the second end of the rocker arm, as depicted in
In a preferred method of operation, camshaft 101 rotates in a manner described in detail hereinabove with respect to
Rotation of first sprocket 204 causes rotation of second sprocket 208 via linkage 207. Second sprocket 208, which is coupled to valve shaft region 34b, then causes partial rotation of intake valve body 30 within valve housing 93 (see
After the intake stroke, and when cam lobe 105 no longer significantly urges cam follower 106 in an upward direction, torsional spring 112 causes rocker arm 210 to return to a relaxed, closed position. When rocker arm 210 is in the closed position, first and second sprockets 204 and 208 are rotated to a position that causes intake valve body 30 to be in the closed state, for example, as shown in
As will be apparent to one skilled in the art, a timing sequence may be arranged so that lobe 108 of cam 107 urges cam follower 109 in an upward direction during an exhaust stroke. When cam follower 109 is urged in the upward direction, the rocker arm coupled to exhaust valve 120 is actuated to cause partial rotation of exhaust valve body 130, in a manner similar to actuation of intake valve 20, as described hereinabove.
Referring now to
In
In the embodiment of
As used herein, the term “aperture” generally refers to an opening caused by an at least partial overlap of first side port 31 with intake passage 95, and/or an opening caused by an at least partial overlap of second side port 32 with intake port 96. For example, referring to
In the embodiment of
In the embodiment of
Referring now to
When rocker arm 210 is actuated by a cam lobe of camshaft 101, as described hereinabove, rocker arm 210 moves between a first position (dashed line in
A reduced aperture size, associated with intake valve 20, may be achieved when means for varying 230a is in the position depicted in
Referring now to
When the solenoid 231 is actuated, and when rocker arm 210 moves between the first position (dashed line in
An increased aperture size, associated with valve 20, may be achieved when means for varying 230a is in the position depicted in
Similarly, reduced and increased aperture sizes, associated with exhaust valve 120, may be achieved using means for varying 230b, thereby allowing the aperture size of the exhaust valve to vary based on an engine's operating conditions.
It should be noted that relatively small variations in distances z1 and z2 may result in relatively significant changes in degrees of rotation ∝1 and ∝2, as depicted in
Advantageously, in accordance with one object of the present invention, varying aperture sizes associated with intake valve 20 and exhaust valve 120 may compensate for differences in engine speed to improve engine efficiency and reduce fuel consumption and emissions. For example, during acceleration periods, increased aperture sizes may be achieved when means for varying 230a is in the position depicted in
In accordance with another object of the present invention, selectively varying an aperture size associated with exhaust valve 120, using means for varying 230b, is expected to improve engine efficiency. Specifically, selectively providing an increased exhaust aperture size, based on engine conditions, may improve exhaust scavenging, thereby removing more unburned hydrocarbon molecules from the combustion chamber and allowing higher compression ratios.
Referring now to
In the embodiment of
The first end of pivoting member 270 comprises coupling point 271, as shown in
When a cable is employed, the cable may be configured to cause coupling point 271 to move in direction “a”, for example, during periods of acceleration. Movement of coupling point 271 in direction “a” causes rod 232′ to be moved in direction “b”, i.e., because pivoting member 270 pivots about pivot point 273.
As described in detail hereinabove with respect to
During cruising and/or idling operating conditions, the cable or other means coupled between the car's gas pedal and coupling point 271 may cause coupling point 271 to move in direction “b”. Movement of coupling point 271 in direction “b” causes rod 232′ to be moved in direction “a”, since pivoting member 270 pivots about pivot point 273.
As described in detail hereinabove with respect to
Referring still to
As will be apparent to one skilled in the art, various other mechanisms may be employed to actuate pivoting member 270 of
Referring now to
Means for actuating 300 comprises first and second solenoids 350a and 350b coupled to intake valve 20 and exhaust valve 120, respectively. Each solenoid is operatively coupled to a respective connecting rod 352. A first connecting rod 352 is coupled to valve shaft region 34b of intake valve 20, while a second connecting rod 352 is coupled to valve shaft region 134b of exhaust valve 120.
The first connecting rod 352 preferably is coupled to valve shaft region 34b using connecting link 374 having slot 377. Sliding pin 375 couples connecting link 374 to the first connecting rod 352, as depicted in
As will be apparent to one skilled in the art, the solenoids 350a and 350b may comprise either a hydraulic, pneumatic or electric solenoid. Actuation signals may be sent to coupling points 351, e.g., using a wire when an electric solenoid is employed. When an electric solenoid is used, an interruption in the provision of a current to coupling points 351 will cause connecting rods 352 to move in a downward direction, as illustrated by the arrows in
In the embodiment of
Referring now to
In
As will be apparent to one skilled in the art, any of the means for actuating described hereinabove with respect to
While preferred illustrative embodiments of the invention are described above, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the invention. The appended claims are intended to cover all such changes and modifications that fall within the true spirit and scope of the invention.
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