US20030213452A1

US20030213452A1 - Rotary driven reciprocating mechanism and method

Info

Publication number: US20030213452A1
Application number: US10/150,853
Authority: US
Inventors: Dan Pomerleau
Original assignee: 42 Inc A Corp OF CANADA
Current assignee: 42 Inc A Corp OF CANADA
Priority date: 2002-05-17
Filing date: 2002-05-17
Publication date: 2003-11-20
Also published as: AU2003240216A8; WO2003098073A2; WO2003098073A3; AU2003240216A1

Abstract

A rotary driven reciprocating mechanism and method permit a rotary motion to be converted into a reciprocating motion that may be used to control the operation of various devices. For example, in a preferred embodiment, the rotary driven reciprocating mechanism may be used for electronic valve timing control in an internal combustion engine. The rotary driven reciprocating mechanism may also be used as a pump valve timing mechanism or for any other purpose in which it is desirable to convert rotary motion into reciprocating motion.

Description

FIELD OF THE INVENTION

The invention relates generally to a rotary driven reciprocating mechanism and in particular to a mechanism that converts rotary motion into a reciprocating motion in order to control the operation of a device.

BACKGROUND OF THE INVENTION

It is desirable to be able to convert a rotary motion into a reciprocating motion to control the operation of a device. For example, the valve timing system and valve system of a typical automobile having an internal combustion engine is an example of a mechanism that converts rotary motion (the camshaft being rotated) into a reciprocal motion (the valve opening and closing) in order to control the operation of the automobile. As is well known, the breathability of an internal combustion engine is directly related to its performance. In more detail, the timing of the opening and closing of the valves of the internal combustion engine are critical to the performance of the automobile, and most particularly to the power and fuel economy of the engine.

As described above, the valve timing in a typical internal combustion engine is provided by a rotating camshaft. The rotating camshaft has cam lobes with a surface profile which define the time during the engine cycle when the valve is open, the duration that the valve remains open and the speed with which the valve opens. In the operation of an internal combustion engine, it is desirable, in order to enhance the performance characteristics of an engine, that the valve timing sequence is varied according to engine speed (so that the valve timing changes depending on the speed of the engine). For example, it is desirable, for almost all internal combustion engines, that the idle speed is low to maximize fuel economy, but that acceptable torque is provided at higher engine speeds (rpms). Unfortunately, the standard internal combustion engine has a fixed cam lobe profile which is a compromise between such competing design parameters. Therefore, in the standard internal combustion engine, it means that regardless of the operating speed of the engine, the valve timing sequence is fixed with the result that engine idle must be inefficiently high and/or that high end performance is compromised.

Various solutions to this problem have been proposed in the past. Most notably, engine designs which incorporate the use of axially displaceable camshafts have been proposed, including Applicant's co-pending application Ser. No. 09/770,179 filed on Jan. 29, 2001 and Ser. No. 09/924,041 filed on Aug. 7, 2001. While each of these designs provide effective ways of varying the timing sequence of internal combustion engine valves as a function of engine speed, they have limited value and utility in that a specific hardware configuration must be physically installed in an internal combustion engine. Accordingly, there has been a need for a valve timing system which enables the valve timing sequence to be controlled by a software program which eliminates the need for a specific hardware configuration of a variable profile camshaft to be installed in the internal combustion engine.

By developing a true Variable Valve Timing system it is possible to eliminate the throttle body and intake manifold (as it exists today) from the air intake system of an internal combustion engine (“engine”). The throttle body is a device used to control air delivery to the intake manifold and from there to the cylinder in an engine. The throttle body is necessary for fixed form camshaft engines since those engines would not be controllable without this type of restriction. In particular, the throttle body reduces the air available to the engine when the engine operator requires the engine to operate at low rpm's. This type of restrictive action produces a vacuum condition in the typical common plenum intake manifold. This vacuum can be as high as 20″ Hg at sea level. This vacuum condition creates an instability in fuel air delivery or charge as it is drawn into the cylinder when the intake valve opens. In more detail, when the intake valve opens to deliver the charge to the cylinder, the vacuum in the intake manifold has to be overcome by the downward movement of the piston during the intake stroke. In most engines, the exhaust valve will also be partially open during a segment of the intake stroke exposing the pressure filled exhaust manifold to this vacuum condition. The inevitable result of this imbalance is that some of the exhaust gases remain in the cylinder inhibiting the effective burning of the fresh intake charge during the power stroke. By using a variable timing system (such as the one described below), it is possible to eliminate the existing throttle body with its common plenum from the air delivery component of the engine. By using the intake-valve(s) to control the air delivery directly, the vacuum condition is eliminated at the intake valve opening and atmospheric pressure is used to push in the new charge and also reduce the ability of the exhaust gases to remain in the cylinder during the intake stroke. This will significantly improve the burning of the charge and increase engine efficiency. (See “Scientific Design of Exhaust and Intake Systems 3 ^rdEdition by Philip H. Smith and John C. Morrison ISBN 0-8376-0309-9) More generally, there is also a need for a new mechanism that converts rotary motion into a reciprocating motion. Such a mechanism may be used for the variable valve timing of an internal combustion engine (as described above), but it may also be used to control a pump and the opening and closing of a pump valve. Thus, it is desirable to provide a rotary driven reciprocating mechanism and method and it is to this end that the present invention is directed.

SUMMARY OF THE INVENTION

The rotary driven reciprocating mechanism in accordance with the invention provides a mechanism for converting rotary motion (from a rotating shaft of a motor) into reciprocating motion (such as the open and closing of a valve). In the context of an internal combustion engine that has a valve timing system that incorporates the rotary driven reciprocating mechanism, the invention provides several advantages. First, the invention provides variable average lift (since the lift of the valve is dependent on the cam track design that can be varied) and the average transit time of the rotary motion can be adjusted to give a greater or lesser average lift during the opening cycle, variable duration (since the speed of the motor during a cycle may be increased or decreased. The invention also provides variable valve phasing between intake and exhaust. The invention provides an extremely light, spring-less valve system capable of supporting extremely high levels of engine rpms. The invention also permits the design of an internal combustion engine with no starter.

In accordance with the invention, the rotary driven reciprocating mechanism has a rotary drive mechanism for each cylinders intake valve or valves and a drive for each exhaust valve or valves. By using a single drive motor for each valve, one can exercise a degree of control beyond anything achievable with a camshaft. For example, on an engine that has a plurality of intake and exhaust valves per cylinder, it would be possible to not only open and close valves at a variety of lift and durations but also to selectively open and close valves, or vary the lift and duration of each intake valve on a cylinder and likewise with the exhaust valves.

The invention is embodied by two slightly different designs. The first design is a driving system wherein the rotary unit has a maximum open and maximum closed format with a transition phase in between. When used on an internal combustion engine (hereinafter “engine”) this system would require significant positional control by the driving mechanism. Specifically, the opening and closing of the “Valve” would necessitate accurate stopping and starting of the drive mechanism. The second design uses a “bent ring or rings” which allow the drive motor to operate continuously without the necessity of stopping and starting. In this design, the driven motor speed may be varied during a single 360° rotation which further optimizes this system. The bent section of the ring which in the drawings provides the open phase of the valve would typically be less than 160° of the ring design though greater sections could be envisioned. As described above, the invention contemplates two different valve designs (which can be used with both of the designs described above) including a standard one piece valve which would necessitate the rotation of the valve even when it is closed and a segmented valve so that the valve does not rotate when it is closed.

In one embodiment, the motor continuously rotates so that the cam follower rotates about the cam track continuously. This embodiment uses either a single piece valve (that rotates as the motor rotates) or a segmented valve which does not rotate with the motor. This embodiment may be used with a higher RPM engine. In this embodiment, a bent-ring cam track is used which permits the motor and cam follower to continuously rotate. In another embodiment, the motor only operates when the valve is being opened or closed and a slanted cam track is used. This embodiment is particularly suited to a lower RPM engine since the motor starts and stops.

Thus, in accordance with the invention, a rotary driven reciprocating mechanism that causes the reciprocating motion of a member is provided. The mechanism comprises a motor that produces a rotational output and a reciprocating member that is coupled to the rotational output of the motor. The mechanism further comprises a cam track affixed to a rigid member wherein the cam track has a track having a first portion and a second portion wherein the first and second portions are at different vertical locations. The reciprocating member further comprises a follower member attached to the reciprocating member so that the follower member rotates around the track in the cam track as the reciprocating member is rotated by the motor so that the reciprocating member moves between an first vertical position when the cam follower is in the first portion of the cam track and a second vertical position when the cam follower is in the second portion of the cam track.

In accordance with another aspect of the invention, a method for imparting a reciprocating motion to a reciprocating element is provided. The method comprises producing a rotary motion using a motor and coupling the rotary motion to a reciprocating member so that the reciprocating member rotates. The rotary motion of the reciprocating member is then converted into an axial motion wherein the reciprocating member travels between a first vertical position and a second vertical position in response to the rotary motion produced by the motor.

In accordance with yet another aspect of the invention, a rotary driven reciprocating mechanism that causes the reciprocating motion of a member wherein the mechanism comprises means for producing a rotational output and a reciprocating means coupled to the rotational output means. The mechanism further comprises means for converting the rotational motion of the rotational output means into a vertical motion of the reciprocating means wherein the converting means further comprising a track having a first portion and a second portion wherein the first and second portions are at different vertical locations. The reciprocating means further comprises following means attached to the reciprocating means wherein the follower means rotates around the track in the track at the reciprocating member is rotated by the motor so that the reciprocating member moves between an first vertical position when the cam follower is in the first portion of the track and a second vertical position when the cam follower is in the second portion of the track so that the reciprocating member moves between the first vertical position and the second vertical position due to the rotation of the motor.

In accordance with still another aspect of the invention, a system for controlling the actuation of valves having a valve stem within a cylinder head in an internal combustion engine is provided. The system comprises a cam track operatively connected to the internal combustion engine where the cam track defines a valve timing path and a cam track follower operatively connected to the valve stem for following the valve timing path defined by the cam track. The mechanism further comprises a motor operatively connected to the cam track follower for causing rotational movement of the cam track follower relative to the cam track and an electronic control system operatively connected to the electric motor for controlling the speed of the motor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a rotary driven reciprocating mechanism in accordance with the invention that may be used as an electronic valve control system in an internal combustion engine; [0014]
FIG. 2 is a front plan view of the rotary driven reciprocating mechanism shown in FIG. 1; [0015]
FIG. 3A is a side cut-away view of the rotary driven reciprocating mechanism shown in FIG. 1 when the valve is in a closed position; [0016]
FIG. 3B is a side cut-away view of the rotary driven reciprocating mechanism shown in FIG. 1 when the valve is in an open position; [0017]
FIG. 3C is a close up view of the cam track and following mechanism shown in FIGS. 3A and 3B; [0018]
FIG. 3D is a chart illustrating the variable valve timing using the rotary driven reciprocating mechanism; [0019]
FIG. 4A is a side cut-away view of a second embodiment of the rotary driven reciprocating mechanism having a slightly different cam track when the valve is in a closed position; [0020]
FIG. 4B is a side cut-away view of the second embodiment of the rotary driven reciprocating mechanism having a slightly different cam track when the valve is in an open position; [0021]
FIG. 4C is a close up view of the cam track and following mechanism shown in FIGS. 4A and 4B; [0022]
FIGS. 5A and 5B are cutaway plan side views of a third embodiment of a rotary driven reciprocating mechanism in accordance with the invention, in a valve open position and a valve closed position, respectively, that serves as an electronic valve control system; [0023]
FIG. 5C is a more detailed view of the follower mechanism shown in FIGS. 5A and 5B; [0024]
FIG. 6A illustrates a fourth embodiment of the rotary driven reciprocating mechanism in accordance with the invention in a valve open position; [0025]
FIG. 6B illustrates the fourth embodiment of the rotary driven reciprocating mechanism in accordance with the invention in a valve closed position; [0026]
FIG. 7 is a side view of a fifth embodiment of the rotary driven reciprocating mechanism in accordance with the invention; [0027]
FIG. 8 is a perspective view of the fifth embodiment of the rotary driven reciprocating mechanism in accordance with the invention; [0028]
FIGS. [0029] 9A-9F are diagrams illustrating further details of the fifth embodiment of the rotary driven reciprocating mechanism in accordance with the invention;
FIG. 10 is an exploded assembly diagram showing the parts of the fifth embodiment of the rotary driven reciprocating mechanism in accordance with the invention; and [0030]
FIGS. 11A and 11B illustrate another embodiment of the rotary driven reciprocating mechanism in accordance with the invention. [0031]

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The invention is particularly applicable to a valve timing mechanism for an internal combustion engine and it is in this context that the invention will be described. It will be appreciated, however, that the rotary driven reciprocating mechanism and method in accordance with the invention has greater utility since the rotary driven reciprocating mechanism and method may be used in any situation in which it is desirable to convert rotary motion into reciprocating motion. For example, although the invention is described with reference to an engine valve timing mechanism, the invention may also be used as a pump valve timing mechanism. [0032]
In accordance with a preferred embodiment of the invention, the rotary driven reciprocating mechanism may be used for an electronic valve timing system for an internal combustion engine. More specifically, the preferred embodiment of the invention provides a system for electric and mechanical control of the valves in an internal combustion engine which enables computer control of the timing of the valves at different engine speeds. The rotary motor may be driven by compressed gas or fluid as well. Now, the electronic valve timing mechanism will be described in more detail. [0033]
FIG. 1 is a perspective view of a first embodiment of a rotary driven [0034] reciprocating mechanism 20 in accordance with the invention that may be used as an electronic valve control system in an internal combustion engine and FIG. 2 is a front plan view of the rotary driven reciprocating mechanism shown in FIG. 1. As an overview, the system provides an electromechanical means for the actuation and control of the valves in an internal combustion engine. As shown, a cylinder head 1 of an internal combustion engine includes a reciprocating valve 15 as is well known that is used to control the flow of fuel and air into the combustion chamber (a piston) and/or the flow of exhaust gases out of the combustion chamber.
In accordance with the invention, a rotary driven [0035] reciprocating mechanism 20 in accordance with the invention is coupled to the valve in order to convert the rotary motion of a motor into the desired reciprocating motion of the valve. The rotary driven reciprocating mechanism 20 may include a motor 13 and a transmission (including a driven gear 10 and a drive gear 11 in one embodiment) for providing the rotational motion to the valve. The invention is not limited to any particular transmission since any mechanism for transferring the rotational motion of the motor to the valve may be used. Accordingly, in this embodiment as described in more detail below, the actuation of the motor 13 causes the valve 15 to spin within the cylinder head. A cam follower 5 (shown in FIGS. 3A and 3B and 3C) projects outwardly of the valve stem and is rigidly fixed to the valve shaft. Thus, as the valve spins, the cam follower spins about the valve stem.
A [0036] cam track 4 is rigidly fixed to the cylinder head 1 and an end portion of the cam follower 5 travels around the cam track as described in more detail below. In general, the cam track 4 defines a circular shape inclined with respect to the axis of the cam follower. The end portion of the cam follower 5 engages with the cam track 4 so that the spinning of the valve stem (and thus the cam follower) causes the cam follower 5 to travel around the cam track 4 thereby imparting an axial reciprocating movement to the valve stem which causes valve opening and closure as shown in FIGS. 3A and 3B, respectively. As the cam track 4 in accordance with the invention causes both the valve opening and the valve closure, the valve stem does not require a valve spring as is typically required with other well known electronic valve control systems.
Returning to FIGS. 1 and 2, the first embodiment of the rotary driven [0037] reciprocating mechanism 20 is located adjacent to and attached to the cylinder block 1 as shown. For a thirty-two valve engine, there would be thirty-two rotary driven mechanisms (one for each valve of the internal combustion engine). The rotary driven reciprocating mechanism 20 comprises a first and second track mount members 2 a, 2 b that are attached to the cylinder block 1 and are located adjacent to each other and are generally parallel to each other. The two track mount members 2 a, 2 b have a cam track 4 rigidly fixed in between them as shown so that the cam track is rigidly fixed in position with respect to the cylinder block 1. In a preferred embodiment, the cam track 4 may be a tube into which the desired tracks are cut. The rotary driven reciprocating mechanism 20 further comprises an upper support 7 which maintains the proper distance between the cam track mount members 2 a, 2 b and supports the driven gear 10. As shown in FIG. 2, the rotary driven reciprocating mechanism 20 further comprises a driven gear 10 and a drive gear 11 that are located adjacent to each other at approximately a right angle to each other wherein the teeth of the drive gear 11 mesh with the teeth of the driven gear 10. In operation, the motor 13, which may be an electric stepper or servo motor with an appropriate feedback position system in a preferred embodiment of the invention, rotates the drive gear 11. The drive gear 11, whose teeth are meshed with the teeth of the driven gear 10, causes the driven gear 10 to rotate which in turn causes the valve 15 to rotate since the valve is fixed to the driven gear 10. In this manner, the activation of the motor 13 causes the valve 15 to rotate. In this embodiment of the invention, the motor 13 is continuously activated so that the valve 15 is continuously rotating with respect to the cylinder block 1. The rotation of the valve 15 in turn causes the opening and closing of the valve as will now be described with reference to FIGS. 3A-3C which show more details of the rotary driven reciprocating mechanism 20.
FIG. 3A is a side cut-away view of the rotary driven [0038] reciprocating mechanism 20 shown in FIG. 1 when the valve is in a closed position, FIG. 3B is a side cut-away view of the rotary driven reciprocating mechanism shown in FIG. 1 when the valve is in an open position and FIG. 3C is a close up view of the cam track and following mechanism shown in FIGS. 3A and 3B. The rotary driven reciprocating mechanism 20 further comprises the cam follower 5 that is attached to the valve 15 (See FIG. 3C) so that the cam follower 5 rotates with the valve. Thus, as the valve and the cam follower rotate, the cam follower 5 follows the cam track 4 which imparts an axial motion on the valve 15 so that the valve moves between the closed position as shown in FIG. 3A and the open position as shown in FIG. 3B.
As shown in FIG. 3C, the [0039] cam track 4 in this embodiment has a bent shape wherein a first portion 4 a of the cam track is flat and is at a vertically higher position than a second portion 4 b of the cam track. In accordance with the invention, the cam track 4 may have the first portion, a transition portion to the second portion, the second portion and then a transition portion back to the first portion to form a circular path. Thus, as the cam follower 5 moves from the first portion 4 a of the cam track to the second portion 4 b of the cam track, the cam follower moves in a vertical direction some predetermined distance, D, as shown in FIG. 3C, which in turn causes the valve 15 to move that same distance, D, as shown in FIG. 3B. The valve therefore moves from the closed position as shown in FIG. 3A (when the cam follower is in the first portion of the cam track) to the open position as shown in FIG. 3B (when the cam follower is in the second portion of the cam track) and back again to the closed position as the cam follower follows the cam track 4. Thus, the combination of the motor 13 and gears 10, 11 as well as the cam track 4 and cam follower 5 translate the rotational motion of the motor 13 into the vertical reciprocating motion of the valve so that the valve is controllable opened and closed. The speed of the valve opening and closing is dependent on the rotation speed of the motor which can be varied to achieve variable valve timing. The time during which the valve is open (the open valve dwell time) and the time during which the valve is closed (the closed valve dwell time) may be varied depending on the particular configuration of the cam track. For example, a longer flat first portion 4 a of the cam track would cause the valve to remain closed for a longer period of time. The particular configuration of the cam track may be varied in accordance with the invention. In a preferred embodiment, the cam track 4 may be a U-shaped track that has been cut into a tube as shown although other shaped tracks may also be used for the cam track and therefore the invention is not limited to any particular cam track shape or configuration. An example of a particular valve timing and achieving it using the rotary driven reciprocating mechanism will now be described.
A typical internal combustion engine will operate at between 400 and 6000 rpm. In order to operate the engine at 6000 rpm, the engine is operating at 100 Hz meaning that the valves open and close 100 times per second. Similarly, at 400 rpm, the valves are opening and closing at approximately 6.6 Hz meaning that the valves open and close 6.6 times per second. Accordingly, the speed of the [0040] motor 13 of the rotary driven reciprocating mechanism must be adjustable between these ranges. In addition to adjusting the speed of the motor 13, the speed profile of the motor must be variable within a single cycle so as to alter the duration of valve opening and closure and the average valve opening or lift. This can be achieved in accordance with the invention by adjusting the speed profile of the motor 13. Now, the connection between the cam follower 5 and the cam track 4 will be described in more detail.
FIG. 3C illustrates a preferred implementation of the connection between the [0041] cam follower 5 and the cam track 4, but the invention is not limited to any particular connection mechanism. As shown in FIG. 3C, the cam follower 5 may include a drive knuckle 22, a drive knuckle bearing 24 and one or more track follower devices 26. The track follower devices 26 may preferably be ball or bearings, but may also be wheels. The track follower devices slide along the inside of the cam track 4.
Returning to FIGS. 3A and 3B, the rotary driven [0042] reciprocating mechanism 20 further includes a motor mount 12 that secures the motor 13 in a predetermined position relative to the cylinder block 1 and the other elements of the rotary drive reciprocating mechanism. The rotary driven reciprocating mechanism further comprises an upper support bearing 8, an external driven spline 9, a Belleville washer 14 and a snap ring that help couple the rotary motion of the driven gear 10 to the valve 15. The mechanism 20 may further include one or more snap rings that are used to connect rotating elements of the mechanism together.
FIG. 3D is a chart illustrating the typical average rpm speeds of the drive motors used in the rotary driven reciprocating mechanism. In particular, given that each valve has its own drive motor, the intake and exhaust drive motors would have an average motor rotation speed equivalent to ½ of the engine speed. The intake and exhaust valves are 180° out of phase with each other. By varying the speed of the drive motors during the open and closed positions, the average lift, duration, overlap of the valve timing and the phasing can be varied for optimal engine performance. For a longer open valve position, a higher transition speed (the transition time from the open position to the closed position) for low RPMs and a lower transition speed at higher RPMs can be used. Now, a second embodiment of the rotary driven reciprocating mechanism will be described. [0043]
FIG. 4A is a side cut-away view of a second embodiment of the rotary driven reciprocating mechanism having a slightly different cam track when the valve is in a closed position, FIG. 4B is a side cut-away view of the second embodiment of the rotary driven reciprocating mechanism when the valve is in an open position and FIG. 4C is a close up view of the cam track and following mechanism shown in FIGS. 4A and 4B. The rotary driven reciprocating mechanism shown in FIGS. [0044] 4A-4C has many of the same elements and the same operation as the rotary driven reciprocating mechanism shown in FIGS. 3A-3C so that those similar elements and the operation of this embodiment of the mechanism will not be described in detail. In this embodiment, the cam track 4 has a slightly different configuration and shape as shown in FIG. 4C. In particular, the cam track has a U shape, but the walls of the cam track are not substantially perpendicular to the floor of the cam track as was the case in the embodiment shown in FIG. 3C. In addition, the transition between the first portion 4 a and the second portion 4 b of the cam track is more gradual and constant whereas the embodiment shown in FIG. 3C had a substantially flat first portion 4 a and transitioned over a short space to the second portion 4 b. Now, another embodiment of the cam track in accordance with the invention will be described with reference to FIGS. 5a-5 c.
FIGS. 5A and 5B are cutaway plan side views of a [0045] third embodiment 30 of a rotary driven reciprocating mechanism in accordance with the invention, in a valve open position and a valve closed position, respectively, that serves as an electronic valve control system and FIG. 5C is a more detailed view of the cam follower mechanism shown in FIGS. 5A and 5B. Again, this embodiment has many of the same elements and operation as the prior embodiments so those similar elements and the operation of this embodiment of the invention will not be described herein. In this embodiment, the cam track 4 has a slightly different configuration and shape. In particular, the first portion of the cam track 4 a is substantially flat along its entire length as shown while the second portion 4 b is gradually sloped as shown. Using this embodiment of the rotary driven reciprocating mechanism, the valve 15 will remain in the closed position for a longer time (since the first portion 4 a is substantially flat) and then will gradually open due to the gradual slope of the second portion 4 b. Now, yet another embodiment of the invention will be described.
FIG. 6A illustrates a fourth embodiment of the rotary driven [0046] reciprocating mechanism 40 in accordance with the invention in a valve open position and FIG. 6B illustrates the fourth embodiment of the rotary driven reciprocating mechanism in accordance with the invention in a valve closed position. As with the above embodiments, this embodiment has many of the same elements and operates in a similar manner so that similar elements will not be described. The overall operation of this embodiment is similar as well except for several differences. In particular, this embodiment of the invention has several additional elements including two cam track first portions 4 a, 4 a′, two cam track second portions 4 b, 4 b′, two cam follower portions 5, 5′ and a rotation joint 42 in the valve. In this embodiment, the cam follower has the two portions 5, 5′ which more evenly distributes the forces associated with moving around the cam track and places those forces on both sides of the valve. In some applications, it may be desirable to distribute the forces in this manner. To accommodate the two cam follower portions, this embodiment also has two cam track first portions 4 a, 4 a′ and two cam track second portions 4 b, 4 b′ as shown which also distributes the forces associated with the valve movement. The rotation joint 42 shown permits an upper portion 44 of the valve to'rotate along with the rotation of the driven gear 10 and the motor 13 (not shown) while a lower portion 46 of the valve does not rotate. In some applications, it may be desirable that the lower portion of the valve does not rotate. In accordance with the invention, the rotation joint 42 may be used with any of the different embodiments of the invention described herein.
All of the embodiments of the invention described above have a continuously rotating [0047] motor 13 so that the above embodiments are particularly applicable to a high RPM engine, such as engines that achieve RPMs as high as 20,000. Now, another embodiment of the invention will be described wherein the motor 13 does not continuously rotate so that this embodiment of the invention is more applicable to lower RPM engines.
FIG. 7 is a side view of a fifth embodiment of the rotary driven [0048] reciprocating mechanism 50 in accordance with the invention and FIG. 8 is a perspective view of the fifth embodiment of the rotary driven reciprocating mechanism. In this embodiment, the motor 13 does not continuously rotate. In particular, the motor 13 will be activated when it is necessary to move the valve between the open position and the closed position, but will otherwise stop. FIGS. 7 and 8 illustrate this embodiment of the invention wherein many of the elements are similar to the prior embodiments and will not be described herein. Except for the fact that the motor 13 stops during the operation of the mechanism, the operation of the mechanism is similar and also will not be described here. FIGS. 9A-9D are further diagrams of this embodiment of the invention wherein the valve is in the closed position whereas FIGS. 9E and 9F are diagrams illustrating the mechanism when the valve is in the open position. FIG. 9C is a sectional view taken along line A-A in FIG. 9A when the valve is closed while FIG. 9E is the same sectional view taken along line A-A in FIG. 9A when the valve is open. To further explain this embodiment of the invention, FIG. 9F will be used which is a close up view of the elements of the mechanism 50 shown in circle C in FIG. 9E.
FIG. 9F illustrates this embodiment of the rotary driven [0049] reciprocating mechanism 50 wherein the motor 13 is only energized when the valve is moving between the open position and the closed position. As shown, the cam track 4 has the first portion 4 a and the second portion 4 b wherein the cam track is a slanted track as shown wherein the valve is closed when the cam follower 5 is in the position shown in FIG. 9C and the valve is open when the cam follower 5 is in the position as shown in FIG. 9F. Unlike the prior embodiments, there is not a flat section of the cam track during which the valve remains closed despite the cam follower 5 moving in the cam track. Thus, when the valve is to be open, the motor is energized so that the cam follower moves in the cam track to the open position. Then, when the valve is to be closed, the motor is again energized so that the cam follower moves in the cam track to the closed position. FIG. 10 is an exploded assembly diagram showing the parts of the fifth embodiment of the rotary driven reciprocating mechanism 50 in accordance with the invention.
In an alternate embodiment of the rotary driven reciprocating mechanism (that is not shown), a tiltable cam track is provided wherein the angle of tilt of the cam track may be varied under control of an actuation system. In this alternative embodiment, the uppermost point of the cam track is pivotally connected to the support system and the lowermost point of the cam track is operatively connected to a linear actuation system which may set the angle of tilt of the cam track as described below in more detail. [0050]
In summary, the invention is embodied by two slightly different designs. The first design is a driving system wherein the rotary unit has a maximum open and maximum closed format with a transition phase in between (See FIGS. [0051] 7-10). When used on an internal combustion engine this system would require significant positional control by the driving mechanism. Specifically, the opening and closing of the “Valve” would necessitate accurate stopping and starting of the drive mechanism. The second design (See FIGS. 1-6) uses a “bent ring or rings” which allow the drive motor to operate continuously without the necessity of stopping and starting. In this design, the driven motor speed may be varied during a single 360° rotation which further optimizes this system as described below. The bent section of the ring would typically be less than 160° of the ring design. As described above, the invention contemplates two different valve designs (which can be used with both of the designs described above) including a standard one piece valve which would necessitate the rotation of the valve even when it is closed and a segmented valve so that the valve does not rotate when it is closed. Now, the actuation system for varying the rotation speed will be described in more detail.
The speed at which the cam track is traced by the cam follower is determined by the rate of rotation of the motor and associated gearing. The rate of rotation of the motor can be controlled by an external engine controller computer, in conjunction with location feedback from the valve assembly. In more detail, the variable speed motor can be either a digitally controlled stepper motor or an analog controlled servomotor depending on the desired characteristic of the overall valve system. [0052]
The location feedback may be a rotary sensor that can track the angular position of the cam follower and/or the position of the valve can be monitored by a linear displacement sensor. These sensors provide the feedback and location information to the engine controller. The sensor may provide analog or digital signals to the engine controller. These signals could be discrete signals at each reference point or continuous, absolute position signals. This information can be used to detect and set the initial position of the valves for engine start and also allow the controller to track the position of the valve as a double check during normal operation. [0053]
In the case of the stepper motor, the engine controller may send a series of pulses to the stepper motor to cause it rotate, either clockwise or counter-clockwise, a fixed amount. By adjusting the timing of these pulses, the engine controller can alter the speed of the stepper motor as it traverses the track. The stepper can also be temporarily stopped at any point in the track to sustain a valve position. In this way, the valve timing can be controlled by controlling the timing of the stepper motor pulses—the valve cycle time can be increased or decreased under direct control of the engine controller. [0054]
By slowing the pulse train while the cam follower is in the portion of the track associated with valve closing, this system allows the valve to close in a slow, controlled manner to prevent the valve from slamming into the valve seat (Note: Track design geometry in the “Bent Track format” and “Tilt Track” causes vertical velocity of the valve to decrease as the valve approaches its seat). By stopping the stepper motor at any position in the cam track will allow the “valve closed” portion of the track to be a much smaller portion of the trace track compared to a constant rate motor. Additionally, the ability to stop at any point in the trace would permit the controller to open the valve to a position less than fully open to allow the engine controller to control the valve lift during the cycle. The ability to change the direction of rotation of the stepper motor will allow the controller to turn the cam follower down the valve opening slope to the desired opening amount, hold that position for the desired time, and the retrace back up the track to close the valve. [0055]
In the case of the servomotor, the engine controller sends an analog signal to the servo motor to cause it rotate, either clockwise or counter-clockwise, a relative amount. By adjusting the amplitude and duration of these pulses, the engine controller can alter the speed of the servo motor as it traverses the track. The servo motor can also be temporarily stopped/stalled at any point in the track to sustain a valve position. In this way, controlling the amplitude and duration of the servo motor control signal can control the valve timing—the valve cycle time can be increased or decreased under direct control by the engine controller. [0056]
By decreasing the amplitude of the servo motor drive signal while the follower is in the portion of the track associated with valve closing, this system allows the valve to close in a slow, controlled manner to prevent the valve from slamming into the valve seat. By stopping the motor at any position in the trace will allow the “valve closed” portion of the trace to be a much smaller portion of the trace track compared to a constant rate motor. Additionally, the ability to stop at any point in the trace would permit the controller to open the valve to a position less than fully open to allow the engine controller to control the valve lift during the cycle. The ability to change the direction of rotation of the servo motor will allow the controller to turn the follower down the valve opening slope to the desired opening amount, hold that position for the desired time, and the retrace back up the track to close the valve. This allows the trace to take a spiral form with multi-turns rather than limiting it to a single 360-degree circle. [0057]
In accordance with the invention, a servo motor system could be constructed with a rotary potentiometer or a proximity sensor attached to either the valve stem or the drive gears. A linear potentiometer could be used to track the vertical displacement of the valve stem. The signals from these sensors could be calibrated against the corresponding valve displacement with a circuit that will provide a displacement signal (analog or digital) to the motor controller. This same signal could be used to automatically adjust the amplitude of the servo motor control signal to adjust the speed of transversal during certain portions of the track either independent from or in conjunction with the engine controller (i.e. the motor control function could be an analog circuit with no micro-controller required). This adjustment allows the track tracing speed to be vaned along the trace allowing a spiral, multi-turn track with a reverse trace. [0058]
In accordance with the invention, instead of the valve being coupled to the motor so that the valve rotates when the motor rotates as described above, the cam track may be connected to the motor so that the cam track rotates as the motor rotates. In this embodiment, the drive apparatus (the motor) may be coupled to the cam track which would be contained in a cylinder wherein the cylinder with the cam track may be rotated by the drive apparatus while the valve remained in a fixed position. The rotating cylinder with the cam track would then transfer an axial displacement to the valve. [0059]
In another embodiment, the “unbent” track (either within a rotating cylinder or in the embodiment described above) is displaced in a manner which allows one end of the track to rise and fall away from and toward the horizontal. For this embodiment, an axle or similar axis pointed located at one end of the track and an axial displacement device are provided wherein the axial displacement device may be actuated by something similar to the electronic valve displacement device herein described or by something as crude as a rotating mechanical camshaft. In the case of a rotating cylinder the cylinder itself would be problematic to tilt in a similar fashion but this can be achieved. [0060]
FIGS. 11A and 11B illustrate another embodiment of the rotary driven [0061] reciprocating mechanism 60 in accordance with the invention wherein a cross track cam track 4 is used. For clarity, the motor and gears are not shown in this embodiment although the same motors and gears described above may be used with this embodiment. This embodiment also operates in the same manner as the other embodiments and therefore the operation of this embodiment which is the same as the prior embodiments will not be described. In this embodiment, the cam track 4 may have the shape shown in FIG. 11A. This cam track permits longer open and closed positions of the valve 15 since there are long flat portions 62, 64 of the cam track 4 wherein the valve is closed when the cam follower 5 is in the flat portion 62 (as shown in FIG. 11A) and the valve is open when the cam follower 5 is in the flat portion 64. The transitions between the open and closed positions are shorter due to the shape of this cam track. FIG. 11B illustrates a top view of the rotary driven reciprocating mechanism 60. It should be understood that a variety of different cam track designs may be used with the invention (although only several illustrative examples are described herein) and the invention is not limited to any particular cam track design.
While the foregoing has been with reference to a particular embodiment of the invention, it will be appreciated by those skilled in the art that changes in this embodiment may be made without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims. [0062]

Claims

1. A rotary driven reciprocating mechanism that causes the reciprocating motion of a member, comprising:

a motor that produces a rotational output;

a reciprocating member that is coupled to the rotational output of the motor;

a cam track affixed to a rigid member, the cam track having a first portion and a second portion connected together wherein the first and second portions are at different vertical locations; and

the reciprocating member further comprises a follower member attached to the reciprocating member wherein the follower member rotates around the track in the cam track at the reciprocating member is rotated by the motor so that the reciprocating member moves between an first vertical position when the cam follower is in the first portion of the cam track and a second vertical position when the cam follower is in the second portion of the cam track so that the reciprocating member moves between the first vertical position and the second vertical position due to the rotation of the motor.

2. The mechanism of claim 1, wherein the motor and follower member rotate continuously during the operation of the mechanism.

3. The mechanism of claim 2, wherein the first portion of the cam track further comprises a flat portion so that the remains in a closed position for some predetermined time during the rotation of the motor and follower member.

4. The mechanism of claim 3, wherein the rotation speed of the motor is varied during an engine cycle to provide variable valve timing.

5. The mechanism of claim 3 further comprising a second follower member and a second cam track wherein the second follower member is located on an opposite side of the follower member to balance the forces of the reciprocating member and wherein the second follower member rotates around the second cam track.

6. The mechanism of claim 2, wherein the reciprocating member further comprises one piece reciprocating member that rotates continuously when the motor rotates.

7. The mechanism of claim 2, wherein the reciprocating member further comprises a rotation joint between an upper portion and a lower portion of the reciprocating member so that the lower portion of the reciprocating member is not required to rotate when the motor rotates.

8. The mechanism of claim 1, wherein the motor and follower member rotate periodically during the operation of the mechanism wherein the motor rotates when the reciprocating member moves between the first and second positions.

9. The mechanism of claim 8, wherein the cam track further comprises a slanted track between the first portion and the second portion.

10. The mechanism of claim 9, wherein the rotation speed of the motor is varied during an engine cycle to provide variable valve timing.

11. The mechanism of claim 9 further comprising a second follower member and a second cam track wherein the second follower member is located on an opposite side of the follower member to balance the forces of the reciprocating member and wherein the second follower member rotates around the second cam track.

12. The mechanism of claim 8, wherein the reciprocating member further comprises a one piece reciprocating member that rotates continuously when the motor rotates.

13. The mechanism of claim 8, wherein the reciprocating member further comprises a rotation joint between an upper portion and a lower portion of the reciprocating member so that the lower portion of the reciprocating member is not required to rotate when the motor rotates.

14. The mechanism of claim 1, wherein the reciprocating member further comprises a one piece reciprocating member that rotates when the motor rotates.

15. The mechanism of claim 1, wherein the reciprocating member further comprises a rotation joint between an upper portion and a lower portion of the reciprocating member so that the lower portion of the reciprocating member is not required to rotate when the motor rotates.

16. The mechanism of claim 1, wherein the rigid member further comprises an engine block and wherein the reciprocating member further comprises a valve in an internal combustion engine.

17. The mechanism of claim 16, wherein the first vertical position comprises a valve open position and the second vertical position further comprises a valve closed position.

18. The mechanism of claim 1, wherein the rigid member further comprises a pump body and wherein the reciprocating member further comprises a pump valve.

19. The mechanism of claim 1 further comprising a transmission that couples the rotational output of the motor to the reciprocating member.

20. The mechanism of claim 19, wherein the transmission further comprises a drive gear connected to the motor and a driven gear located adjacent to the drive gear wherein the teeth of the drive gear are meshed with the teeth of the driven gear.

21. A method for imparting a reciprocating motion to a reciprocating element, the method comprising:

producing a rotary motion using a motor;

coupling the rotary motion to a reciprocating member so that the reciprocating member rotates;

converting the rotary motion of the reciprocating member into an axial motion wherein the reciprocating member travels between a first vertical position and a second vertical position in response to the rotary motion produced by the motor.

22. The method of claim 21, wherein the converting step further comprises providing a follower member to the reciprocating member wherein the follower member rotates around a track in a cam track and the reciprocating member is rotated by the motor so that the reciprocating member moves between an first vertical position when the cam follower is in the first portion of the cam track and a second vertical position when the cam follower is in the second portion of the cam track so that the reciprocating member moves between the first vertical position and the second vertical position due to the rotation of the motor.

23. The method of claim 22, wherein the producing step further comprises continuously producing rotary motion.

24. The method of claim 23, wherein the producing rotary motion further comprises varying the rotation speed of the motor during an engine cycle to provide variable valve timing.

25. The method of claim 23, wherein the converting further comprises providing a second follower member and a second cam track wherein the second follower member is located on an opposite side of the follower member to balance the forces of the reciprocating member and wherein the second follower member rotates around the second cam track.

26. The method of claim 22, wherein the producing rotary motion further comprises periodically producing rotary motion wherein the motor rotates when the reciprocating member is moving between the first and second positions.

27. The method of claim 26, wherein the rotation speed of the motor is varied during an engine cycle to provide variable valve timing.

28. The method of claim 26, wherein the converting further comprises providing a second follower member and a second cam track wherein the second follower member is located on an opposite side of the follower member to balance the forces of the reciprocating member and wherein the second follower member rotates around the second cam track.

29. A rotary driven reciprocating mechanism that causes the reciprocating motion of a member, comprising:

means for producing a rotational output;

a reciprocating means coupled to the rotational output means;

means for converting the rotational motion of the rotational output means into a vertical motion of the reciprocating means, the converting means further comprising a track having a first portion and a second portion wherein the first and second portions are at different vertical locations; and

the reciprocating means further comprises following means attached to the reciprocating means wherein the follower means rotates around the track in the track at the reciprocating member is rotated by the motor so that the reciprocating member moves between an first vertical position when the cam follower is in the first portion of the track and a second vertical position when the cam follower is in the second portion of the track so that the reciprocating member moves between the first vertical position and the second vertical position due to the rotation of the motor.

30. The mechanism of claim 29, wherein the rotation producing means and follower means rotate continuously during the operation of the mechanism.

31. The mechanism of claim 30, wherein the first portion of the track further comprises a flat portion so that the valve remains closed for some predetermined time during the rotation of the rotation producing means and follower means.

32. The mechanism of claim 31, wherein the rotation speed of the rotation producing means is varied during an engine cycle to provide variable valve timing.

33. The mechanism of claim 31 further comprising a second follower means and a second track wherein the second follower means is located on an opposite side of the follower means to balance the forces of the reciprocating means and wherein the second follower means rotates around the second track.

34. The mechanism of claim 30, wherein the reciprocating means further comprises a one piece reciprocating member that rotates continuously when the rotation producing means rotates.

35. The mechanism of claim 30, wherein the reciprocating means further comprises a rotation joint between an upper portion and a lower portion of the reciprocating means so that the lower portion of the reciprocating means is not required to rotate when the rotation producing means rotates.

36. The mechanism of claim 29, wherein the rotation producing means and the follower means rotate periodically during the operation of the mechanism.

37. The mechanism of claim 36, wherein the track further comprises a slanted track between the first portion and the second portion.

38. The mechanism of claim 37, wherein the rotation speed of the rotation producing means is varied during an engine cycle to provide variable valve timing.

39. The mechanism of claim 37 further comprising a second follower means and a second track wherein the second follower means is located on an opposite side of the follower means to balance the forces of the reciprocating means and wherein the second follower means rotates around the second track.

40. The mechanism of claim 36, wherein the reciprocating means further comprises a one piece reciprocating means that rotates continuously when the rotation producing means rotates.

41. The mechanism of claim 36, wherein the reciprocating means further comprises a rotation joint between an upper portion and a lower portion of the reciprocating means so that the lower portion of the reciprocating means is not required to rotate when the rotation producing means rotates.

42. The mechanism of claim 29, wherein the reciprocating means further comprises a one piece reciprocating means that rotates when the rotation producing means rotates.

43. The mechanism of claim 29, wherein the reciprocating means further comprises a rotation joint between an upper portion and a lower portion of the reciprocating means so that the lower portion of the reciprocating means is not required to rotate when the rotation producing means rotates.

44. The mechanism of claim 29, wherein the rigid member further comprises an cylinder head and wherein the reciprocating member further comprises a valve in an internal combustion engine.

45. The mechanism of claim 44, wherein the first vertical position comprises a valve open position and the second vertical position further comprises a valve closed position.

46. The mechanism of claim 29, wherein the rigid member further comprises a pump body and wherein the reciprocating member further comprises a pump valve.

47. The mechanism of claim 29 further comprising a transmission that couples the rotational output of the motor to the reciprocating member.

48. The mechanism of claim 47, wherein the transmission further comprises a drive gear connected to the motor and a driven gear located adjacent to the drive gear wherein the teeth of the drive gear are meshed with the teeth of the driven gear.

49. A system for controlling the actuation of valves having a valve stem within a cylinder head in an internal combustion engine comprising:

a cam track operatively connected to the internal combustion engine, the cam track defining a valve timing path;

a cam track follower operatively connected to the valve stem for following the valve timing path defined by the cam track;

a motor operatively connected to the cam track follower for causing rotational movement of the cam track follower relative to the cam track;

an electronic control system operatively connected to the electric motor for controlling the speed of the motor.

50. A system as in claim 49, wherein the electric motor is operatively connected to the valve stem and the valve rotates with respect to the cylinder head.

51. A system as in claim 49, wherein the electric motor is operatively connected to the cam track and cam track rotates with respect to the valve stem.

52. A system as in claim 49 further comprising a linear actuation system operatively connected to the cam track and wherein the cam track is tiltable with respect to the valve stem and wherein actuation of the linear actuation causes tilting of the cam track with respect to the valve stem.

53. A system as in claim 49 wherein the electronic controller varies the speed of rotation within one rotation cycle.

54. A system as in claim 49, wherein the tip of the cam follower includes a biasing system.

55. A system as in claim 49, wherein the tip of the cam follower includes a roller.

56. A system as in claim 49, wherein the transmission system.

57. A system of claim 49, wherein the motor is powered by one of air and other fluids and gases.