CA1329077C - Valve operating mechanism in an internal combustion engine - Google Patents
Valve operating mechanism in an internal combustion engineInfo
- Publication number
- CA1329077C CA1329077C CA000545383A CA545383A CA1329077C CA 1329077 C CA1329077 C CA 1329077C CA 000545383 A CA000545383 A CA 000545383A CA 545383 A CA545383 A CA 545383A CA 1329077 C CA1329077 C CA 1329077C
- Authority
- CA
- Canada
- Prior art keywords
- cams
- cam followers
- engine
- cam
- valve operating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/12—Transmitting gear between valve drive and valve
- F01L1/18—Rocking arms or levers
- F01L1/181—Centre pivot rocking arms
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
- F01L1/267—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder with means for varying the timing or the lift of the valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
- F02F1/24—Cylinder heads
- F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
- F02F1/4214—Shape or arrangement of intake or exhaust channels in cylinder heads specially adapted for four or more valves per cylinder
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
- F02F1/24—Cylinder heads
- F02F2001/244—Arrangement of valve stems in cylinder heads
- F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis
Abstract
ABSTRACT
Valve operating apparatus for an internal combustion engine in which plural intake valves and exhaust valves are associated with each cylinder. The respective valves are operated in one engine-operating condition in response to the action of a first set of cams and in another engine-operating condition in response to the action of a second set of cams coupled to the first cam set. The cams operating the intake valves impart a different valve operating action than those operating the exhaust valves.
Valve operating apparatus for an internal combustion engine in which plural intake valves and exhaust valves are associated with each cylinder. The respective valves are operated in one engine-operating condition in response to the action of a first set of cams and in another engine-operating condition in response to the action of a second set of cams coupled to the first cam set. The cams operating the intake valves impart a different valve operating action than those operating the exhaust valves.
Description
1 3~9~71 VALVE OPERATING APPARATUS FOR
AN INTERNAL COMBUSTION ENGINE
BACKGROUND OF THE INVENTION
The present invention relates to a valve operating apparatus for an internal combustion engine. More particularly, the ; invention involves valve operating apparatus capable of changing the modes of operation of both the intake valves and the exhaust valves associated with the cylind~r of an internal combustion , engine according to varying operating conditions of the engine.
Japanese Laid-Open Patent Publication Nos. 59-226216 and 61-19911 are directed to valve operating mechanisms of the described type~ These mechanisms are designed such that the intake valves and the exhaust valves have substantially the same operating modes. Since exhaust gas emitted from an engine has a high temperature and flows at a high velocity, it is desirable that, under certain conditions, the exhaust valve have a cross-sectional area of valve opening which is smaller than that of the intake v lve. Where the above prior art valve operating mechanisms are designed to operate the intake and exhaust valves ~: i -~ in accordance with substantially the same operation modes it is , ,~ . .
impossible to operate the respective valves to accommodate changing the exhaust valve opening appropriately under these , certain conditions.
It is to the amelioration of this problem, therefore, that ..-the present invention is directed.
SllMMARY OF THE INVENTION
` According to the present invention, the intake and exhaust valve operating mechanisms are arranged such that the operation modes of the intake and the exhaust valves operated thereby can be different from each other. Since the respective intake and :" ~
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~, exhaust valves can be made to operate ln dlfferent modes of j operatlon they can each be accurately operated in such :~ dlfferent modes of operatlon.
It is, therefore, an ob~ect of the invention to provlde a valve operatlng apparatus for an lnternal combustion engine capable of opening and closlng the respective intake and exhaust valves accurately ln their respectlve operatlon modes.
According to a broad aspect of the invention there ls provlded valve operating means for controlling the operatlon of lntake and exhaust valve rneans ln an internal combustion . engine, comprislng:
`~ camshaft means rotatable in synchronism with rotation of sald engine;
a first set of cam followers operatively connected to said lntake valve means;
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a second set of cam followers operatlvely connected to ,,~ said exhaust valve means;
,~s,~ means for selectlvely connectlng the cam followers of the ~ respective sets for either independent or unlted operatlon;
.~: 20 a plurality of cams rotatably driven by said camshaft .i : means lncludlng a flrst set of cams for operatlny sald flrst . ~ .
. set of cam followers and a second set of cams for operatlng ,; sald second set of cam followers under an operating mode different from that of said flrst cam followers;
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said flrst set of cams belng effectlve to operate the cam .~i ~. followers of said first set mutually identically under each "."r, respective conditlon of englne operatlon; and . ., 1, ~., said second set of cams being effective to operate the cam .v followers of said second set mutually differently under one condition of engine operatlon and mutually identlcally under : another condltion of engine operatlon.
; Accordlng to another broad aspect of the lnvention ~ B 2 ~' there ls provided valve operatlng means for controlling the . operation of a plurality of intake valve and a plurallty of exhaust valves ln an internal combustion engine, comprising:
camshaft means rotatable in synchronism wlth rotation of said engine;
a flrst set of cam followers operatlvely connected to said intake valves~
~ a second set of cam followers operatlvely connected to ,~ said exhaust valves;
~ 10 means for selectlvely connecting the cam followers of the .j respective sets for elther lndependent or unlted operatlon;
~ a plurallty of cams rotatably driven by sald camshaft :.s means lncludlng a flrst set of cams for operatlng said first .'. set of carn followers and a second set of cams for operatlng , said second set of cam followers under an operatlng mode dlfferent from that of sald first carn followers?
sald flrst set of cams belng effectlve to operate each of said intake valves mutually ldentically under each respectlve s~ condltlon of englne operatlon; and said second set of cams belng effectlve to operate each of sald exhaust valves mutually differently under one condition of 's. englne operatlon and mutually ldentlcally under another v con~ltlon of engine operation.
,` For a better understandlng of the lnvention, lts sperating advantages and the speclflc ob~ectlves obtained by ~ lts use, reference should be made to the accompanylng drawlngs ;.~ and descrlptlon whlch relate to a preferred embodlment thereof.
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BRIEF DESCRIPTION OF THE DRAWINGS
Flgure 1 ls a sectlonal elevatlonal view of an lnternal combustlon englne lncorporatlng the present lnventlon;
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~ Flgure 2 ls a partlal plan vlew of the lnternal .
` 1 32qo77 combustlon englne of Flgure l;
Flgure 3 ls a sectional view taken along llne III of Figure 2;
Flgure 4 ls a diagram lllustrating various valve operating profiles;
.~ Figure 5 is an enlarged sectlonal vlew taken along line V-V of Figure 1 illustratlng an intake valve operating mechanism ln its disconnected state;
: Flgure 6 ls a view slmilar to Figure 5 lllustrating , 10 the intake valve operatlng mechanism ln its interconnected -~; state;
Flgure 7 is an enlarged sectional view taken along llne VII~VII of figure 1 lllustratlng the exhaust valve . operating mechanisrn~
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Figure 8 is a partial plan view similar to Figure 2 illustrating a second embodiment o the present invention; .
Figure 9 is a is a sectional elevational view illustrating a third embodiment of the present invention; ::
Figure 10 is a partial plan view of the embodiment of Figure 9; and Figure 11 is a partial plan view illustrating a fourth embodiment o the present invention.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS OF T~E INVENTION
In Figure 1, which shows a first embodiment of the present invention, a piston 3 is reciprocally movable in the cylinder 2 of an engine body 1. A cylinder head 4, which covers the cylinder 2, has a pair of intake holes 6a, 6b provided adjacent to each other and communicating with intake ports 5. The cylinder head 4 also contains a pair of exhaust holes 8a, 8b provided adjacent to each other and communicating with exhaust ports 7.
Both the intake holes 6a, 6b and the exhaust holes 8a, 8b open into a combustion chamber 9. Intake valves 10a, 10b are openably and closably disposed in the respective intake holes 6a, 6b and exhaust valves lla, lb are similarly disposed in the respective exhaust holes 8a, 8b. The intake valves lOa, lOb are movably inserted through a pair of guide sleeves 12 extending vertically through the cylinder head 4, and the exhaust valves lla, llb are similarly movably inserted through a pair of guide sleeves 13 extending vertically through the cylinder head 4. Retainers 14 14b, and 15a, 15b are mounted on the upper ends of the intake valves 10a, 10b and the exhaust valves lla, llb, respectively.
The intake valves 10a, 10b and the exhaust valves lla, llb are normally urged to close the intake holes 6a, 6b and the exhaust ~ 32907-~
holes 8a, 8b, respectively, un~er the bias of valve sprinys 16a, 16b and 17a, 17b interposed between the respective retainers 14a, 14b and l5a, 15b and the cylinder head 4. The intake valves lOa, lOb are openably and closably driven by the respective intake and exhaust valve operating mechanisms 18 and 19 disposed above the cylinder head 4.
As shown in Figure 2t the intake valve operating mechanism 1~ has a pair of low-speed cams 21 and a high-speed cam 22, each of which are integrally formed on a camshaft 20a. The camshaft 20a is rotatable in synchronism with the rotation of the engine, desirably at a speed ratio of 1/2 with respect to the speed of rotation of the engine. First, second, and third intake rocker arrns 24, 25, 26 are pivotally supported as intake cam followers on a rocker shaft 23 parallel to the camshaft 20a.
The exhaust valve operating mechanism 19 has a low-speed cam 27 and a high-speed cam 28 which are integrally formed on a camshaft 20b. Th~ camshaft 20b is similarly rotatable in synchronism with rotation of the engine at a speed ratio of 1/2 with respect to the speed of rotation of the engine. First and .
second exhaust rocker arms 30, 31 are pivotally supported as exhaust cam followers on a rocker shaft 29 parallel to the camshaft 20b.
Xn the intake valve operating mechanism 18, the camshaft 20a is rotatably disposed above the cylinder head 4. The low-speed cams 21 which operate the intake valves lOa, lOb~ are integrally formed on the camshaft 20a. ~he high-speed cam 22, which is also integrally formed on the camshaft 20a~ is located between the respective low-speed cams 21.
~ he rocker shaft 23 is fixed below, and extends parallel to, the camshaft 20a. The first, second, and third intake rocker :
: ~ 329~77 arms 24, 25, 26 are pivotally s~pported on the rocker shaft 23.
The first and second intake rocker arms 24, 25 have base portions swingably supported on the rocker shaft 23 and extend to positions above the intake valves lOa, lOb. The first and second intake rocker arms 24, 25 have on their upper portions cam slippers 32, 33 held in sliding corltact with the respective low-.~ ~ speed cams 21. Tappet screws 34, 35 are threaded through the ends of the first and second intake rocker arms 24, 25 above the intake valves 10, lOb, and are engageable with the upper ends of the intake valves lOa, lOb. The intake valves lOa, lOb are thereby operatively coupled to the first and second intake rocker ; arms 24, 25~ respectively, by the tappet screws 34, 35.
. As also shown in Figure 3, the third intake rocker arm 26 is .. pivotally supported on the rocker shaft 23 between the first and second intake rocker arms 24, 25. The third intake rocker arm 26 extends slightly from the rocker shaft 23 toward the intake valves lOa, lOb, and has on its upper portion a cam slipper 36 :x~ held in sliding contact with the high-speed cam 22. A hollow . cylindrical lifter 37 has its closed end held against the lower ;
surface of the end of the thîrd intake rocker arm 26. The lifter ~: 37 is normally urged to move upwardly by a lifter spring 38 ' interposed between the cylinder head 4 and the lifter 37. The s~ cam slipper 36 of the third intake rocker arm 26 is thus held in ~; sliding contact with the high-speed cam 22 at all times by the .~ spring-biased lifter 37.
. In the exhaust valve operat ng mechanism 19, the camshaft 20b is rotatably disposed above the cylinder head 4 and extends :
; parallel to the camshaft 20a. The low-speed cam 27 i integrally -~ formed on the camshaft 20b in a position to operate the exhaust `~ valve lla, and the high-speed cam 28 is integrally formed on the camshaft 20b in a po5ition to operate the exhaust valve llb.
~ 3~c~077 - The low-speed cam 27 of the exhaust valve sperating mechanism 19 is of a different cam profile than that of the low-speed cams 21 of the intake valve operating mechanism 18~ The low-speed cams 21 of the intake valve operating mechanism 18 have a valve operating profile as indicated by curve A in Figure 4, whereas the low-speed cam 27 of the exhaust valve operating mechanism 19 has a valve operating profile as indicated by curve B. Similarly, the high-speed cam 28 of the exhaust valve operating mechanism 19 is of a different cam profile than that of the high-speed cams 28 of the intake valve operating mechanism ~ 18. The high-speed cams 22 have a valve operating profile as `~ indicated by curve C in Figure 4, whereas the high-speed cam 28 has a valve operating profile as indicated by curve D therein.
The rocker shaft 29 over the exhaust valves lla, llb is positioned below and extends parallel to the camshaft 20b. The 1 first exhaust rocker arm 30 is pivotally supported on the rocker shaft 29 in a position to operate the exhaust valve lla, whereas the second exhaust rocker arm 31 is pivotally supported on the ~......... rocker shaft 29 in a position to operate the exhaust valve llb.
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~' The exhaust rocker arms 30, 31 extend to positions overlying ~he ~ exhaust valves lla, llb, respectively. Tappet screws 39, 40 are ;t' threaded through the ends of the exhaust rocker arms 30, 31 and ~ are engageable with the upper ends of the respective exhaust :`~ valves lla, llb so that the exhaust valves lla, llb are operatively coupled to the respective exhaust rocker arms 30, 31. The exhaust rocker arms 30, 31 have on their upper portions cam slippers 41, 42 held in sl.iding contact with the respective . low- and high-speed cams 27, 28.
.' As illustrated in Figure 5, the first, second and third ~ intake rocker arms 24, 25 and 26 of the intake valve operating ~.' ~` -6-i ''.
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-" ~ 3~9077 mechanism 18 have their lateral sides held in mutually sliding contact and a select;ve coupling 43 is disposed beween the rocker arms 24 through 26.
The selective coupling 43 comprises a first coupling pin 44 capable of connecting the first and third intake rocker arms 24, 26 and a second coupling pin 45 capable of connecting the third and second intake rocker arms 26, 25. The second coupling pin 45 is held coaxially against the first coupling pin 44. Also provided is a stopper 46 for limiting the movement of the first and second coupling pins 44, 45, and a spring 47 for urging the coupling pins 44, 45 to disconnect the rocker arms from each other.
The first intake rocker arm 24 has a first guide hole 48 extending parallel to the rocker shaft 23. The hole 43 is closed at one end and has its other end opening toward the third intake rocker arm 26. The first coupling pin 44 is slidably fitted in the first guide hole 48. The closed end of the first guide hole 48 and the adjacent end of the first coupling pin 44 cooperate to define a hydraulic pressure chamber 49 therebetween. The first intake rocker arm 24 has a hydraulic passage 50 communicating with the hydraulic pressure chamber 49. The rocker shaft 23 has a hydraulic passage 51 extending axially therethrough and communicating with a hydraulic pressure source (not shown). The hydraulic passages 50, 51 are held in communication with each other at all times irrespective of the extent to which the first intake rocker arm 24 is angularly moved, through a hole 52 d fined in the side wall of the rocker shaft 23.
The first coupling pin 44 has a projection extending from one end thereof, which is engageable with the closed end of the first guide hole 4d. The iirst coupling pin 44 is provided with ~' ~ 3~9077 ~` :
an axial length such that, when the abutting projection 53 abuts against the closed end of the first guide hole 48, the opposite end of the first coupling pin 44 is positioned at the interface between the first and third intake rocker arms 24, 26.
The guide hole 54 defined in the third intake rocker arm 26 extends parallel to the rocker shaft 23 and opens at the opposite sides of the third intake rocker arm 26. The guide hole 54 is thus capable of registry with the first guide hole 48. The :
second coupling pin 45 is slidably fitted in the guide hole 54, and has a length equal to the length of the guide hole 54. The outside diameter of the second coupling pin 45 is the same as the outside diameter of the first coupling pin 44.
The second intake rocker arm 25 contains a second guide hole 55 having one end closed and its other end opening toward the third intake rocker arm 26, such that it is capable of registry with the guide hole 54. A generally cylindrical stopper 46, which is of the same outside diameter as that of the second coupling pin 45, is slidably fitted in the second guide hole 55. A shaft 56 is coaxially joined to the stopper 46. The second intake rocker arm 25 has a guide hole S7 defined coaxially through the closed end of the second guide hole 55 to receive the shaft 56 for sliding movement therethrough.
A coil spring 47 is disposed around the shaft 56 between the stopper 46 and the closed end of the second guide hole 55. The stopper 46 and the first and second coupling pins 44, 45 are thus :,..
i~ resiliently urged toward the closed end of the guide hole 48 in .} the first intake rocker arm 24 under the bias of the spring 47.
J When no hydraulic pressure is applied to the hydraulic `. pressure chamber 49, the abutting projection 53 on the first coupling pin 44 is held in abutment against the closed end of the ~: -8-"
,.
t 3~9~77 `-first guide hole 48 by the spring 47. In this condition, the abutting surfaces of the first and second coupling pins 44, 45 are located at the interface between the first and third intake rocker arms 24, 26, and the abutting surfaces of the second coupling pin 45 and the stopper 46 are located at the interface between the third and second intake rocker arms 26, 25.
Therefore, the first and third intake rocker arms 24, 26 are relatively angularly movable while holding the facing ends of the first and second coupling pins 44, 45 in sliding contact with each other. The third and second intake rocker arms 26, 25 are similarly relatively angularly movable while holding the facing ends of the second coupling pin 45 and of the stopper 46 in sliding contact with each other. With the selective coupling 43 thus in its disconnected state, the first and second intake rocker arms 24, 25 are angularly moved by the low-speed cams 21, whereas the third intake rocker arm 26 is angularly moved by the high-speed cam 22.
When the passage 51 and, concomitantly, the hydraulic pressure chamber 49 is supplied with hydraulic pressure, the first coupling pin 44 pushes the second coupling pin 45 and the stopper 46 against the resiliency of the spring 47, thereby . ~
forcing a portion of the ~irst coupling pin 44 to extend into the guide hole 54 and a portion of the second coupling pin 45 to extend into the second guide hole 55, as shown in Figure 6. With the pins disposed in this position, the first through third intake rocker arms 24 through 26 are prevented from swinging relative to each other, but, instead, are caused to swing in unison. Since the amount of angular movement of the third intake rocker arm 26 held in sliding contact with the high-speed cam 22 is greatest, the first and second intake rocker arms 24, 25 swing _g_ 1 32~77 with the third intake rocker arm 26 according to the cam profile of the high-speed cam 22.
As shown in Figure 7, the lateral sides of the ~irst and second exhaust rocker arms 30, 31 of the exhaust valve operating mechanism l9 are held in mutually sliding contact, and a selective coupling 60 is disposed between them~ The selective coupling 60 comprises a coupling pin 61 movable between a position in which it interconnects the first and second exhaust rocker arms 30, 31 and a position in which it disconnects them from each other. Stopper 62 is operative to limit the movement of the coupling pin 51, and a spring 63 is operative for urging the stopper 62 to move the coupling pin 61 toward the position to disconnect the exhaust rocker arms 30, 31 from each other.
The second exhaust rocker arm 31 has a guide hole 64 extending parallel to the rocker shaft 29. The hole 64 is closed at one end and has its other end opening toward the first exhaust rocker arm 30. The coupling pin 61 is slidably fitted in the guide hole 640 The closed end of the guide hole 64 and the coupling pin 61 cooperate to define a hydraulic pressure chamber 67 therebetween. The second exhaust rocker arm 31 has a hydraulic passage 68 communicating with the hydraulic pressure chamber 67. ~he rocker shaft 29 has a hydraulic passage 70 held in communication with the hydraulic passage 68 at all times through a hole 69 defined in a side wall of the rocker shaft 29.
The coupling pin 61 has an axial length selected such that, when one end thereof abuts against the closed end of the guide hole 64, the opposite end is positioned at the interface between the first and second exhaust rocker arms 30, 31.
A guide hole 75 is defined in the first exhaust rocker arm 30 and opens toward the second exhaust rocker arm 31. The guide , } --1 0--:
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~ 3~9~77 hole 75 has the same diameter as that of the guide hole 64 and is capable of registry with the guide hole 54. The circular stopper 62 is slidably fitted in the guide hole 75. The first exhaus~
rocker arm 30 has a smaller-diameter hole 72 co~munica~ing with the guide hole 70 with a step 71 therebetween. A still smaller-diameter guide hole 73 coaxial with the hole 72 penetrates the .
closed end of the first exhaust rocker arm 30. A shaft 74 is coaxailly joined to the stopper 72 and is movable through the guide hole 73.
The coil spring 63 is concentrically disposed around theshaft 74 between the facing surface of the stopper 62 and that of the closed end of the hole 72. The stopper 62 and the coupling pin 61 are thus urged toward the closed end of the guide hole 64 :
~ in the rocker arm 31 under the bias of the spriny 63.
i: When no hydraulic pressure is applied to the hydraulic ; pressure chamber 67, the coupling pin 61 is held in abutment against the closed end of the guide hole 64 by ~he spring 63. In :~ this condition, the abutting surfaces of the coupling pin 61 and the stopper 62 are located at the înterface between the first and ~ second exhaust rocker arms 30, 31. Therefore, the first and : third exhaust rocker arms 30, 31 are relatively angularly , .
movable~ while the abutting surfaces of the coupling pin 61 and the stopper 62 are held in sliding contact with each other. The first exhaust rocker arm 30 is thus angularly moved by the low-speed cam 27, whereas the second exhaust rocker arm 31 is angularly moved by the high-speed cam 2B.
When the hydraulic pressure chamber 67 is supplied with hydraulic pressure, the coupling pin 61 is caused to push the stopper 62 against the resiliency of the spring 63 to thereby force a portion of the coupling pin 61 into the guide hole 70.
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''-` ' 1 32qo77 In this position, the first and second exhaust rocker arms 30, 31 are prevented from swinging with respect to each other, but instead, are caused to swing in unison. Since the amount of angular movement of the second exhaust rocker arm 31 held in - sliding contact with the high-speed cam 28 is greater, the first exhaust rocker arm 30 is caused to swing with the second exhaust rocker arm 31 according to the cam profile of the high-speed cam 28.
;The operation of the above-described arrangement is as follows. During low-speed operation of the engine, no hydraulic pressure is supplied to the hydraulic pressure chambers 49, 67 of the selective couplings 43, 60. At this time, the selective couplings 43, 60 are in their disconnecting position, so that the first through third intake rocker arms, 24, 25 and 26, are all relatively angularly movable. The first and second exhaust rocker arms 30, 31 are also relatively anglarly movable.
. ., Therefore, the intake valves lOa, lOb are opened and closed .
according to the valve operating profile shown by curve A in Figure 4 and dependent on the cam profile of the low-speed cams 21~ The exhaust valve lla, on the other hand, is opened and closed according to the valve operating profile shown by curve B
in Figure 4 and the exhaust valve llb is opened and closed :1, according to the valve operating profile shown by curve D in -; Figure 4.
During high-speed operation of the engine, hydraulic pressure is supplied to the hydraulic pressure chambers 49, 67 of the selective couplings 43, 60. Thus, the selective couplings :
43, 60 are in their respective connecting positions, so that the first through third intake rocker arms, 24, 25 and 26, are angularly moved in unison and the first and second exhaust rocker . .. .
s -12-( ~.' .:-.~,, ` 1 329077 arm~ 30, 31 are also angularly moved in unison. Therefore, the intake valves lOa, lOb are opened and closed according to the valve operating profile shown by curve C in Figure 4 and the exhaust valves lla, llb are opened and closed according to the valve operating profile shown by curve D in Figure 4.
From the above it will be appreciated that the operation modes of the intake valves lOa, lOb and the exhaust valves lla, llb, i~e., the opening and closing timings and the amounts of lift thereof, are made different from each other when the engine is in either low-speed or high-speed operation. In the exhaust valve operating mechanism 19, the exhaust valves lla, llb engage the two exhaust rocker arms 30, 31, such that no lifter such as that indicated as 37 is required. Accordingly, the exhaust valve operating mechanism 19 is reduced in weight and cost.
As a modification of the above-described embodiment of the invention, either one of the low-speed cams 31 in the intake valve operating mechanism 18 may be of such a shape as to provide a valve operating profile as indicated by curve E in Figure 4 whereby the associated valve is caus~d to open only slightly.
Figure 8 shows a second embodiment of the present invention in which parts that correspond to those of the first embodment are denoted by identical reference characters. In this embodiment the exhaust valve operating mechanism 19 has a circular raised portion 78 disposed on the camshaft 20b corresponding to the first exhaust rocker arm 30, and a cam 76 disposed on the camshaft 20b corresponding to the second exhaust rocker arm 31. The cam 76 is of a cam profile different from that of the cams 21, 22 of the intake valve operating mechanism.
,~, i 1 3~9077 In this second embodiment, during low-speed operation of the engine~ the first exhaust rocker arm 30 is held in sliding contact with the ircular raised portion 78 and hence is not angularly moved, thereby keeping the exhaust valve lla closed.
The second exhaust rocker arm 31, on the other hand, is angularly moved by the cam 76, thereby enabling the other exhaust valve llb to be opened and closed at the timing and lift dictated by the profile of the cam 76~ During high-speed operation of the engine, by actuation of the exhaust valve operating mechanism 19, both exhaust rocker arms 30, 31 are angularly moved by the cam 76, thereby enabling both exhaust valves lla, llb to be opened and closed at the timing and lift according to the profile of the cam 76.
With the exhaust valve lla remaining closed during low-speed operation of the engine, any friction produced by the valve operation during low-speed engine operation can be reduced.
Moreover, in a resonant rotation range ~2,000 rpm to 3,000 rpm) of a timing belt (not shown) for driving the camshaft 20b, the maximum load on the timing belt can be reduced by keeping the exhaust valve lla closed, so that the width of the timing belt can be reduced or the safety factor thereof increased.
When the exhaust valve lla remains closed during low-speed operation, the valve lla may stick to it5 valve seat, or the load on the camshaf 20b may vary to a large extent upon starting the valve lla from the closed position. To avoid these problems, the circular raised portion 78 may be replaced with an ultra-low-speed cam which only slightly opens the exhaust valve lla. With this arrangement, the problems of valve sticking and increased load change can be eliminated while substantially keeping the advantages arising from continuously closing the exhaust valve lla.
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~., ,., Figures 9 and 10 illustrate a third embodiment of the present invention in which parts that correspond to those of the previous embodiments are designated by identical reference characters. According to this embodiment, a single camshaft 20, such as is characteristic of single overhead cam internal combustion engines, is shared by intake and exhaust valve operating mechanisms 18a, l9a, and is rotatably disposed between the rocker shafts 23, 29. The camshaft 20 has low-speed cams 21 held in sliding contact with first and second intake rocker arms 24~ 25 and a high-speed cam 22 held in sliding contact with a third intake rocker arm 26. A circular raised portion 78 is held in sliding contact with a first exhaust rocker arm 30 and a cam 76 held in sliding contact with a second exhaust rocker arm 31.
The first through third intake rocker arms, 24 though 26, have a selective cvupling which is of the same structure as that of the selective coupling 43 described above, and the first and second exhaust rocker arms 30, 31 have a selective coupling which is of the same structure as that of the selective coupling 50 described above.
Figure 11 shows a fourth embodiment of the present invention. According to this embodimPnt the intake valve operating mechanism 18b has only two intake rocker arms 24', 25' similar to the previously described exhaust valve operating mechanism but both intake valves lOa, lOb are operatively coupled to one of the rocker arms 24'. In this embodiment, the number of cams and the number of rocker arms are reduced, thereby producing a valve operating arrangement of smaller size.
It will be appreciated that, by means of the hereindescribed invention, the intake and exhaust valve operating mechanisms are configured and arranged such that the intake and exhaust valves, ' ~ -15-;
whose operation they control, can be imparted with opening and closing movements that correspond precisely with the movements desired in the various operating modes of the engine.
Although certain preferred embodiments of the invention have been shown and described it should be understood that various changes can be made therein without departing from the scope of the appended claims.
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AN INTERNAL COMBUSTION ENGINE
BACKGROUND OF THE INVENTION
The present invention relates to a valve operating apparatus for an internal combustion engine. More particularly, the ; invention involves valve operating apparatus capable of changing the modes of operation of both the intake valves and the exhaust valves associated with the cylind~r of an internal combustion , engine according to varying operating conditions of the engine.
Japanese Laid-Open Patent Publication Nos. 59-226216 and 61-19911 are directed to valve operating mechanisms of the described type~ These mechanisms are designed such that the intake valves and the exhaust valves have substantially the same operating modes. Since exhaust gas emitted from an engine has a high temperature and flows at a high velocity, it is desirable that, under certain conditions, the exhaust valve have a cross-sectional area of valve opening which is smaller than that of the intake v lve. Where the above prior art valve operating mechanisms are designed to operate the intake and exhaust valves ~: i -~ in accordance with substantially the same operation modes it is , ,~ . .
impossible to operate the respective valves to accommodate changing the exhaust valve opening appropriately under these , certain conditions.
It is to the amelioration of this problem, therefore, that ..-the present invention is directed.
SllMMARY OF THE INVENTION
` According to the present invention, the intake and exhaust valve operating mechanisms are arranged such that the operation modes of the intake and the exhaust valves operated thereby can be different from each other. Since the respective intake and :" ~
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~, exhaust valves can be made to operate ln dlfferent modes of j operatlon they can each be accurately operated in such :~ dlfferent modes of operatlon.
It is, therefore, an ob~ect of the invention to provlde a valve operatlng apparatus for an lnternal combustion engine capable of opening and closlng the respective intake and exhaust valves accurately ln their respectlve operatlon modes.
According to a broad aspect of the invention there ls provlded valve operating means for controlling the operatlon of lntake and exhaust valve rneans ln an internal combustion . engine, comprislng:
`~ camshaft means rotatable in synchronism with rotation of sald engine;
a first set of cam followers operatively connected to said lntake valve means;
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a second set of cam followers operatlvely connected to ,,~ said exhaust valve means;
,~s,~ means for selectlvely connectlng the cam followers of the ~ respective sets for either independent or unlted operatlon;
.~: 20 a plurality of cams rotatably driven by said camshaft .i : means lncludlng a flrst set of cams for operatlny sald flrst . ~ .
. set of cam followers and a second set of cams for operatlng ,; sald second set of cam followers under an operating mode different from that of said flrst cam followers;
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said flrst set of cams belng effectlve to operate the cam .~i ~. followers of said first set mutually identically under each "."r, respective conditlon of englne operatlon; and . ., 1, ~., said second set of cams being effective to operate the cam .v followers of said second set mutually differently under one condition of engine operatlon and mutually identlcally under : another condltion of engine operatlon.
; Accordlng to another broad aspect of the lnvention ~ B 2 ~' there ls provided valve operatlng means for controlling the . operation of a plurality of intake valve and a plurallty of exhaust valves ln an internal combustion engine, comprising:
camshaft means rotatable in synchronism wlth rotation of said engine;
a flrst set of cam followers operatlvely connected to said intake valves~
~ a second set of cam followers operatlvely connected to ,~ said exhaust valves;
~ 10 means for selectlvely connecting the cam followers of the .j respective sets for elther lndependent or unlted operatlon;
~ a plurallty of cams rotatably driven by sald camshaft :.s means lncludlng a flrst set of cams for operatlng said first .'. set of carn followers and a second set of cams for operatlng , said second set of cam followers under an operatlng mode dlfferent from that of sald first carn followers?
sald flrst set of cams belng effectlve to operate each of said intake valves mutually ldentically under each respectlve s~ condltlon of englne operatlon; and said second set of cams belng effectlve to operate each of sald exhaust valves mutually differently under one condition of 's. englne operatlon and mutually ldentlcally under another v con~ltlon of engine operation.
,` For a better understandlng of the lnvention, lts sperating advantages and the speclflc ob~ectlves obtained by ~ lts use, reference should be made to the accompanylng drawlngs ;.~ and descrlptlon whlch relate to a preferred embodlment thereof.
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BRIEF DESCRIPTION OF THE DRAWINGS
Flgure 1 ls a sectlonal elevatlonal view of an lnternal combustlon englne lncorporatlng the present lnventlon;
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~ Flgure 2 ls a partlal plan vlew of the lnternal .
` 1 32qo77 combustlon englne of Flgure l;
Flgure 3 ls a sectional view taken along llne III of Figure 2;
Flgure 4 ls a diagram lllustrating various valve operating profiles;
.~ Figure 5 is an enlarged sectlonal vlew taken along line V-V of Figure 1 illustratlng an intake valve operating mechanism ln its disconnected state;
: Flgure 6 ls a view slmilar to Figure 5 lllustrating , 10 the intake valve operatlng mechanism ln its interconnected -~; state;
Flgure 7 is an enlarged sectional view taken along llne VII~VII of figure 1 lllustratlng the exhaust valve . operating mechanisrn~
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Figure 8 is a partial plan view similar to Figure 2 illustrating a second embodiment o the present invention; .
Figure 9 is a is a sectional elevational view illustrating a third embodiment of the present invention; ::
Figure 10 is a partial plan view of the embodiment of Figure 9; and Figure 11 is a partial plan view illustrating a fourth embodiment o the present invention.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS OF T~E INVENTION
In Figure 1, which shows a first embodiment of the present invention, a piston 3 is reciprocally movable in the cylinder 2 of an engine body 1. A cylinder head 4, which covers the cylinder 2, has a pair of intake holes 6a, 6b provided adjacent to each other and communicating with intake ports 5. The cylinder head 4 also contains a pair of exhaust holes 8a, 8b provided adjacent to each other and communicating with exhaust ports 7.
Both the intake holes 6a, 6b and the exhaust holes 8a, 8b open into a combustion chamber 9. Intake valves 10a, 10b are openably and closably disposed in the respective intake holes 6a, 6b and exhaust valves lla, lb are similarly disposed in the respective exhaust holes 8a, 8b. The intake valves lOa, lOb are movably inserted through a pair of guide sleeves 12 extending vertically through the cylinder head 4, and the exhaust valves lla, llb are similarly movably inserted through a pair of guide sleeves 13 extending vertically through the cylinder head 4. Retainers 14 14b, and 15a, 15b are mounted on the upper ends of the intake valves 10a, 10b and the exhaust valves lla, llb, respectively.
The intake valves 10a, 10b and the exhaust valves lla, llb are normally urged to close the intake holes 6a, 6b and the exhaust ~ 32907-~
holes 8a, 8b, respectively, un~er the bias of valve sprinys 16a, 16b and 17a, 17b interposed between the respective retainers 14a, 14b and l5a, 15b and the cylinder head 4. The intake valves lOa, lOb are openably and closably driven by the respective intake and exhaust valve operating mechanisms 18 and 19 disposed above the cylinder head 4.
As shown in Figure 2t the intake valve operating mechanism 1~ has a pair of low-speed cams 21 and a high-speed cam 22, each of which are integrally formed on a camshaft 20a. The camshaft 20a is rotatable in synchronism with the rotation of the engine, desirably at a speed ratio of 1/2 with respect to the speed of rotation of the engine. First, second, and third intake rocker arrns 24, 25, 26 are pivotally supported as intake cam followers on a rocker shaft 23 parallel to the camshaft 20a.
The exhaust valve operating mechanism 19 has a low-speed cam 27 and a high-speed cam 28 which are integrally formed on a camshaft 20b. Th~ camshaft 20b is similarly rotatable in synchronism with rotation of the engine at a speed ratio of 1/2 with respect to the speed of rotation of the engine. First and .
second exhaust rocker arms 30, 31 are pivotally supported as exhaust cam followers on a rocker shaft 29 parallel to the camshaft 20b.
Xn the intake valve operating mechanism 18, the camshaft 20a is rotatably disposed above the cylinder head 4. The low-speed cams 21 which operate the intake valves lOa, lOb~ are integrally formed on the camshaft 20a. ~he high-speed cam 22, which is also integrally formed on the camshaft 20a~ is located between the respective low-speed cams 21.
~ he rocker shaft 23 is fixed below, and extends parallel to, the camshaft 20a. The first, second, and third intake rocker :
: ~ 329~77 arms 24, 25, 26 are pivotally s~pported on the rocker shaft 23.
The first and second intake rocker arms 24, 25 have base portions swingably supported on the rocker shaft 23 and extend to positions above the intake valves lOa, lOb. The first and second intake rocker arms 24, 25 have on their upper portions cam slippers 32, 33 held in sliding corltact with the respective low-.~ ~ speed cams 21. Tappet screws 34, 35 are threaded through the ends of the first and second intake rocker arms 24, 25 above the intake valves 10, lOb, and are engageable with the upper ends of the intake valves lOa, lOb. The intake valves lOa, lOb are thereby operatively coupled to the first and second intake rocker ; arms 24, 25~ respectively, by the tappet screws 34, 35.
. As also shown in Figure 3, the third intake rocker arm 26 is .. pivotally supported on the rocker shaft 23 between the first and second intake rocker arms 24, 25. The third intake rocker arm 26 extends slightly from the rocker shaft 23 toward the intake valves lOa, lOb, and has on its upper portion a cam slipper 36 :x~ held in sliding contact with the high-speed cam 22. A hollow . cylindrical lifter 37 has its closed end held against the lower ;
surface of the end of the thîrd intake rocker arm 26. The lifter ~: 37 is normally urged to move upwardly by a lifter spring 38 ' interposed between the cylinder head 4 and the lifter 37. The s~ cam slipper 36 of the third intake rocker arm 26 is thus held in ~; sliding contact with the high-speed cam 22 at all times by the .~ spring-biased lifter 37.
. In the exhaust valve operat ng mechanism 19, the camshaft 20b is rotatably disposed above the cylinder head 4 and extends :
; parallel to the camshaft 20a. The low-speed cam 27 i integrally -~ formed on the camshaft 20b in a position to operate the exhaust `~ valve lla, and the high-speed cam 28 is integrally formed on the camshaft 20b in a po5ition to operate the exhaust valve llb.
~ 3~c~077 - The low-speed cam 27 of the exhaust valve sperating mechanism 19 is of a different cam profile than that of the low-speed cams 21 of the intake valve operating mechanism 18~ The low-speed cams 21 of the intake valve operating mechanism 18 have a valve operating profile as indicated by curve A in Figure 4, whereas the low-speed cam 27 of the exhaust valve operating mechanism 19 has a valve operating profile as indicated by curve B. Similarly, the high-speed cam 28 of the exhaust valve operating mechanism 19 is of a different cam profile than that of the high-speed cams 28 of the intake valve operating mechanism ~ 18. The high-speed cams 22 have a valve operating profile as `~ indicated by curve C in Figure 4, whereas the high-speed cam 28 has a valve operating profile as indicated by curve D therein.
The rocker shaft 29 over the exhaust valves lla, llb is positioned below and extends parallel to the camshaft 20b. The 1 first exhaust rocker arm 30 is pivotally supported on the rocker shaft 29 in a position to operate the exhaust valve lla, whereas the second exhaust rocker arm 31 is pivotally supported on the ~......... rocker shaft 29 in a position to operate the exhaust valve llb.
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~' The exhaust rocker arms 30, 31 extend to positions overlying ~he ~ exhaust valves lla, llb, respectively. Tappet screws 39, 40 are ;t' threaded through the ends of the exhaust rocker arms 30, 31 and ~ are engageable with the upper ends of the respective exhaust :`~ valves lla, llb so that the exhaust valves lla, llb are operatively coupled to the respective exhaust rocker arms 30, 31. The exhaust rocker arms 30, 31 have on their upper portions cam slippers 41, 42 held in sl.iding contact with the respective . low- and high-speed cams 27, 28.
.' As illustrated in Figure 5, the first, second and third ~ intake rocker arms 24, 25 and 26 of the intake valve operating ~.' ~` -6-i ''.
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-" ~ 3~9077 mechanism 18 have their lateral sides held in mutually sliding contact and a select;ve coupling 43 is disposed beween the rocker arms 24 through 26.
The selective coupling 43 comprises a first coupling pin 44 capable of connecting the first and third intake rocker arms 24, 26 and a second coupling pin 45 capable of connecting the third and second intake rocker arms 26, 25. The second coupling pin 45 is held coaxially against the first coupling pin 44. Also provided is a stopper 46 for limiting the movement of the first and second coupling pins 44, 45, and a spring 47 for urging the coupling pins 44, 45 to disconnect the rocker arms from each other.
The first intake rocker arm 24 has a first guide hole 48 extending parallel to the rocker shaft 23. The hole 43 is closed at one end and has its other end opening toward the third intake rocker arm 26. The first coupling pin 44 is slidably fitted in the first guide hole 48. The closed end of the first guide hole 48 and the adjacent end of the first coupling pin 44 cooperate to define a hydraulic pressure chamber 49 therebetween. The first intake rocker arm 24 has a hydraulic passage 50 communicating with the hydraulic pressure chamber 49. The rocker shaft 23 has a hydraulic passage 51 extending axially therethrough and communicating with a hydraulic pressure source (not shown). The hydraulic passages 50, 51 are held in communication with each other at all times irrespective of the extent to which the first intake rocker arm 24 is angularly moved, through a hole 52 d fined in the side wall of the rocker shaft 23.
The first coupling pin 44 has a projection extending from one end thereof, which is engageable with the closed end of the first guide hole 4d. The iirst coupling pin 44 is provided with ~' ~ 3~9077 ~` :
an axial length such that, when the abutting projection 53 abuts against the closed end of the first guide hole 48, the opposite end of the first coupling pin 44 is positioned at the interface between the first and third intake rocker arms 24, 26.
The guide hole 54 defined in the third intake rocker arm 26 extends parallel to the rocker shaft 23 and opens at the opposite sides of the third intake rocker arm 26. The guide hole 54 is thus capable of registry with the first guide hole 48. The :
second coupling pin 45 is slidably fitted in the guide hole 54, and has a length equal to the length of the guide hole 54. The outside diameter of the second coupling pin 45 is the same as the outside diameter of the first coupling pin 44.
The second intake rocker arm 25 contains a second guide hole 55 having one end closed and its other end opening toward the third intake rocker arm 26, such that it is capable of registry with the guide hole 54. A generally cylindrical stopper 46, which is of the same outside diameter as that of the second coupling pin 45, is slidably fitted in the second guide hole 55. A shaft 56 is coaxially joined to the stopper 46. The second intake rocker arm 25 has a guide hole S7 defined coaxially through the closed end of the second guide hole 55 to receive the shaft 56 for sliding movement therethrough.
A coil spring 47 is disposed around the shaft 56 between the stopper 46 and the closed end of the second guide hole 55. The stopper 46 and the first and second coupling pins 44, 45 are thus :,..
i~ resiliently urged toward the closed end of the guide hole 48 in .} the first intake rocker arm 24 under the bias of the spring 47.
J When no hydraulic pressure is applied to the hydraulic `. pressure chamber 49, the abutting projection 53 on the first coupling pin 44 is held in abutment against the closed end of the ~: -8-"
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t 3~9~77 `-first guide hole 48 by the spring 47. In this condition, the abutting surfaces of the first and second coupling pins 44, 45 are located at the interface between the first and third intake rocker arms 24, 26, and the abutting surfaces of the second coupling pin 45 and the stopper 46 are located at the interface between the third and second intake rocker arms 26, 25.
Therefore, the first and third intake rocker arms 24, 26 are relatively angularly movable while holding the facing ends of the first and second coupling pins 44, 45 in sliding contact with each other. The third and second intake rocker arms 26, 25 are similarly relatively angularly movable while holding the facing ends of the second coupling pin 45 and of the stopper 46 in sliding contact with each other. With the selective coupling 43 thus in its disconnected state, the first and second intake rocker arms 24, 25 are angularly moved by the low-speed cams 21, whereas the third intake rocker arm 26 is angularly moved by the high-speed cam 22.
When the passage 51 and, concomitantly, the hydraulic pressure chamber 49 is supplied with hydraulic pressure, the first coupling pin 44 pushes the second coupling pin 45 and the stopper 46 against the resiliency of the spring 47, thereby . ~
forcing a portion of the ~irst coupling pin 44 to extend into the guide hole 54 and a portion of the second coupling pin 45 to extend into the second guide hole 55, as shown in Figure 6. With the pins disposed in this position, the first through third intake rocker arms 24 through 26 are prevented from swinging relative to each other, but, instead, are caused to swing in unison. Since the amount of angular movement of the third intake rocker arm 26 held in sliding contact with the high-speed cam 22 is greatest, the first and second intake rocker arms 24, 25 swing _g_ 1 32~77 with the third intake rocker arm 26 according to the cam profile of the high-speed cam 22.
As shown in Figure 7, the lateral sides of the ~irst and second exhaust rocker arms 30, 31 of the exhaust valve operating mechanism l9 are held in mutually sliding contact, and a selective coupling 60 is disposed between them~ The selective coupling 60 comprises a coupling pin 61 movable between a position in which it interconnects the first and second exhaust rocker arms 30, 31 and a position in which it disconnects them from each other. Stopper 62 is operative to limit the movement of the coupling pin 51, and a spring 63 is operative for urging the stopper 62 to move the coupling pin 61 toward the position to disconnect the exhaust rocker arms 30, 31 from each other.
The second exhaust rocker arm 31 has a guide hole 64 extending parallel to the rocker shaft 29. The hole 64 is closed at one end and has its other end opening toward the first exhaust rocker arm 30. The coupling pin 61 is slidably fitted in the guide hole 640 The closed end of the guide hole 64 and the coupling pin 61 cooperate to define a hydraulic pressure chamber 67 therebetween. The second exhaust rocker arm 31 has a hydraulic passage 68 communicating with the hydraulic pressure chamber 67. ~he rocker shaft 29 has a hydraulic passage 70 held in communication with the hydraulic passage 68 at all times through a hole 69 defined in a side wall of the rocker shaft 29.
The coupling pin 61 has an axial length selected such that, when one end thereof abuts against the closed end of the guide hole 64, the opposite end is positioned at the interface between the first and second exhaust rocker arms 30, 31.
A guide hole 75 is defined in the first exhaust rocker arm 30 and opens toward the second exhaust rocker arm 31. The guide , } --1 0--:
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~ 3~9~77 hole 75 has the same diameter as that of the guide hole 64 and is capable of registry with the guide hole 54. The circular stopper 62 is slidably fitted in the guide hole 75. The first exhaus~
rocker arm 30 has a smaller-diameter hole 72 co~munica~ing with the guide hole 70 with a step 71 therebetween. A still smaller-diameter guide hole 73 coaxial with the hole 72 penetrates the .
closed end of the first exhaust rocker arm 30. A shaft 74 is coaxailly joined to the stopper 72 and is movable through the guide hole 73.
The coil spring 63 is concentrically disposed around theshaft 74 between the facing surface of the stopper 62 and that of the closed end of the hole 72. The stopper 62 and the coupling pin 61 are thus urged toward the closed end of the guide hole 64 :
~ in the rocker arm 31 under the bias of the spriny 63.
i: When no hydraulic pressure is applied to the hydraulic ; pressure chamber 67, the coupling pin 61 is held in abutment against the closed end of the guide hole 64 by ~he spring 63. In :~ this condition, the abutting surfaces of the coupling pin 61 and the stopper 62 are located at the înterface between the first and ~ second exhaust rocker arms 30, 31. Therefore, the first and : third exhaust rocker arms 30, 31 are relatively angularly , .
movable~ while the abutting surfaces of the coupling pin 61 and the stopper 62 are held in sliding contact with each other. The first exhaust rocker arm 30 is thus angularly moved by the low-speed cam 27, whereas the second exhaust rocker arm 31 is angularly moved by the high-speed cam 2B.
When the hydraulic pressure chamber 67 is supplied with hydraulic pressure, the coupling pin 61 is caused to push the stopper 62 against the resiliency of the spring 63 to thereby force a portion of the coupling pin 61 into the guide hole 70.
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''-` ' 1 32qo77 In this position, the first and second exhaust rocker arms 30, 31 are prevented from swinging with respect to each other, but instead, are caused to swing in unison. Since the amount of angular movement of the second exhaust rocker arm 31 held in - sliding contact with the high-speed cam 28 is greater, the first exhaust rocker arm 30 is caused to swing with the second exhaust rocker arm 31 according to the cam profile of the high-speed cam 28.
;The operation of the above-described arrangement is as follows. During low-speed operation of the engine, no hydraulic pressure is supplied to the hydraulic pressure chambers 49, 67 of the selective couplings 43, 60. At this time, the selective couplings 43, 60 are in their disconnecting position, so that the first through third intake rocker arms, 24, 25 and 26, are all relatively angularly movable. The first and second exhaust rocker arms 30, 31 are also relatively anglarly movable.
. ., Therefore, the intake valves lOa, lOb are opened and closed .
according to the valve operating profile shown by curve A in Figure 4 and dependent on the cam profile of the low-speed cams 21~ The exhaust valve lla, on the other hand, is opened and closed according to the valve operating profile shown by curve B
in Figure 4 and the exhaust valve llb is opened and closed :1, according to the valve operating profile shown by curve D in -; Figure 4.
During high-speed operation of the engine, hydraulic pressure is supplied to the hydraulic pressure chambers 49, 67 of the selective couplings 43, 60. Thus, the selective couplings :
43, 60 are in their respective connecting positions, so that the first through third intake rocker arms, 24, 25 and 26, are angularly moved in unison and the first and second exhaust rocker . .. .
s -12-( ~.' .:-.~,, ` 1 329077 arm~ 30, 31 are also angularly moved in unison. Therefore, the intake valves lOa, lOb are opened and closed according to the valve operating profile shown by curve C in Figure 4 and the exhaust valves lla, llb are opened and closed according to the valve operating profile shown by curve D in Figure 4.
From the above it will be appreciated that the operation modes of the intake valves lOa, lOb and the exhaust valves lla, llb, i~e., the opening and closing timings and the amounts of lift thereof, are made different from each other when the engine is in either low-speed or high-speed operation. In the exhaust valve operating mechanism 19, the exhaust valves lla, llb engage the two exhaust rocker arms 30, 31, such that no lifter such as that indicated as 37 is required. Accordingly, the exhaust valve operating mechanism 19 is reduced in weight and cost.
As a modification of the above-described embodiment of the invention, either one of the low-speed cams 31 in the intake valve operating mechanism 18 may be of such a shape as to provide a valve operating profile as indicated by curve E in Figure 4 whereby the associated valve is caus~d to open only slightly.
Figure 8 shows a second embodiment of the present invention in which parts that correspond to those of the first embodment are denoted by identical reference characters. In this embodiment the exhaust valve operating mechanism 19 has a circular raised portion 78 disposed on the camshaft 20b corresponding to the first exhaust rocker arm 30, and a cam 76 disposed on the camshaft 20b corresponding to the second exhaust rocker arm 31. The cam 76 is of a cam profile different from that of the cams 21, 22 of the intake valve operating mechanism.
,~, i 1 3~9077 In this second embodiment, during low-speed operation of the engine~ the first exhaust rocker arm 30 is held in sliding contact with the ircular raised portion 78 and hence is not angularly moved, thereby keeping the exhaust valve lla closed.
The second exhaust rocker arm 31, on the other hand, is angularly moved by the cam 76, thereby enabling the other exhaust valve llb to be opened and closed at the timing and lift dictated by the profile of the cam 76~ During high-speed operation of the engine, by actuation of the exhaust valve operating mechanism 19, both exhaust rocker arms 30, 31 are angularly moved by the cam 76, thereby enabling both exhaust valves lla, llb to be opened and closed at the timing and lift according to the profile of the cam 76.
With the exhaust valve lla remaining closed during low-speed operation of the engine, any friction produced by the valve operation during low-speed engine operation can be reduced.
Moreover, in a resonant rotation range ~2,000 rpm to 3,000 rpm) of a timing belt (not shown) for driving the camshaft 20b, the maximum load on the timing belt can be reduced by keeping the exhaust valve lla closed, so that the width of the timing belt can be reduced or the safety factor thereof increased.
When the exhaust valve lla remains closed during low-speed operation, the valve lla may stick to it5 valve seat, or the load on the camshaf 20b may vary to a large extent upon starting the valve lla from the closed position. To avoid these problems, the circular raised portion 78 may be replaced with an ultra-low-speed cam which only slightly opens the exhaust valve lla. With this arrangement, the problems of valve sticking and increased load change can be eliminated while substantially keeping the advantages arising from continuously closing the exhaust valve lla.
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~., ,., Figures 9 and 10 illustrate a third embodiment of the present invention in which parts that correspond to those of the previous embodiments are designated by identical reference characters. According to this embodiment, a single camshaft 20, such as is characteristic of single overhead cam internal combustion engines, is shared by intake and exhaust valve operating mechanisms 18a, l9a, and is rotatably disposed between the rocker shafts 23, 29. The camshaft 20 has low-speed cams 21 held in sliding contact with first and second intake rocker arms 24~ 25 and a high-speed cam 22 held in sliding contact with a third intake rocker arm 26. A circular raised portion 78 is held in sliding contact with a first exhaust rocker arm 30 and a cam 76 held in sliding contact with a second exhaust rocker arm 31.
The first through third intake rocker arms, 24 though 26, have a selective cvupling which is of the same structure as that of the selective coupling 43 described above, and the first and second exhaust rocker arms 30, 31 have a selective coupling which is of the same structure as that of the selective coupling 50 described above.
Figure 11 shows a fourth embodiment of the present invention. According to this embodimPnt the intake valve operating mechanism 18b has only two intake rocker arms 24', 25' similar to the previously described exhaust valve operating mechanism but both intake valves lOa, lOb are operatively coupled to one of the rocker arms 24'. In this embodiment, the number of cams and the number of rocker arms are reduced, thereby producing a valve operating arrangement of smaller size.
It will be appreciated that, by means of the hereindescribed invention, the intake and exhaust valve operating mechanisms are configured and arranged such that the intake and exhaust valves, ' ~ -15-;
whose operation they control, can be imparted with opening and closing movements that correspond precisely with the movements desired in the various operating modes of the engine.
Although certain preferred embodiments of the invention have been shown and described it should be understood that various changes can be made therein without departing from the scope of the appended claims.
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Claims (12)
1. Valve operating means for controlling the operation of intake and exhaust valve means in an internal combustion engine, comprising:
camshaft means rotatable in synchronism with notation of said engine;
a first set of cam followers operatively connected to said intake valve means;
a second set of cam followers operatively connected to said exhaust valve means;
means for selectively connecting the cam followers of the respective sets for either independent or united operation;
a plurality of cams rotatably driven by said camshaft means including a first set of cams for operating said first set of cam followers and a second set of cams for operating said second set of cam followers under an operating mode different from that of said first cam followers;
said first set of cams being effective to operate the cam followers of said first set mutually identically under each respective condition of engine operation; and said second set of cams being effective to operate the cam followers of said second set mutually differently under one condition of engine operation and mutually identically under another condition of engine operation.
camshaft means rotatable in synchronism with notation of said engine;
a first set of cam followers operatively connected to said intake valve means;
a second set of cam followers operatively connected to said exhaust valve means;
means for selectively connecting the cam followers of the respective sets for either independent or united operation;
a plurality of cams rotatably driven by said camshaft means including a first set of cams for operating said first set of cam followers and a second set of cams for operating said second set of cam followers under an operating mode different from that of said first cam followers;
said first set of cams being effective to operate the cam followers of said first set mutually identically under each respective condition of engine operation; and said second set of cams being effective to operate the cam followers of said second set mutually differently under one condition of engine operation and mutually identically under another condition of engine operation.
2. The valve operating means according to claim 1 in which said first set of cams includes first cams having corresponding cam profiles for operating said cam followers in said first set identically under one condition of engine operation when said first set of cam followers operate independently of one another and another cam having a cam profile different from that of said first cams for operating said cam followers in said first set identically when said first set of cam followers are united under another condition of engine operation.
3. The valve operating means according to claim 2 in which said first set of cam followers operate independently during low speed operation of said engine and in unison during high speed operation thereof.
4. The valve operating means according to claim 2 in which said second set of cams includes cams of different cam profiles and being operative to operate said second set of cam followers mutually differently under one condition of engine operation when said second set of cam followers operate independently of one another and identically according to the profile of one of said cams under another condition of engine operation when said second set of cam followers operate in unison.
5. The valve operating means according to claim 4 in which the cam followers in each of the respective sets operate independently during low speed operation of said engine and in unison during high speed operation of said engine.
6. Valve operating means for controlling the operation of a plurality of intake valves and a plurality of exhaust valves in an internal combustion engine, comprising:
camshaft means rotatable in synchronism with rotation of said engine;
a first set of cam followers operatively connected to said intake valves;
a second set of cam followers operatively connected to said exhaust valves;
means for selectively connecting the cam followers of the respective sets for either independent or united operation;
a plurality of cams rotatably driven by said camshaft means including a first set of cams for operating said first set of cam followers and a second set of cams for operating said second set of cam followers under an operating mode different from that of said first cam followers;
said first set of cams being effective to operate each of said intake valves mutually identically under each respective condition of engine operation; and said second set of cams being effective to operate each of said exhaust valves mutually differently under one condition of engine operation and mutually identically under another condition of engine operation.
camshaft means rotatable in synchronism with rotation of said engine;
a first set of cam followers operatively connected to said intake valves;
a second set of cam followers operatively connected to said exhaust valves;
means for selectively connecting the cam followers of the respective sets for either independent or united operation;
a plurality of cams rotatably driven by said camshaft means including a first set of cams for operating said first set of cam followers and a second set of cams for operating said second set of cam followers under an operating mode different from that of said first cam followers;
said first set of cams being effective to operate each of said intake valves mutually identically under each respective condition of engine operation; and said second set of cams being effective to operate each of said exhaust valves mutually differently under one condition of engine operation and mutually identically under another condition of engine operation.
7. The valve operating means according to claim 6 in which said first set of cams includes first cams having corresponding cam profiles for operating said intake valves identically under one condition of engine operation when said first set of cam followers operate independently of one another and another cam having a cam profile different from that of said first cams for operating said intake valves identically when said first set of cam followers are united under another condition of engine operation.
8. The valve operating means according to claim 7 in which said first set of cam followers operate independently during low speed operation of said engine and in unison during high speed operation thereof.
9. The valve operating means according to claim 7 in which said second set of cams includes cams of different cam profiles and being operative to operate said exhaust valves mutually differently under one condition of engine operation when said second set of cam followers operate independently of one another and identically according to the profile of one of said cams under another condition of engine operation when said second set of cam followers operate in unison.
10. The valve operating means according to claim 9 in which the cam followers in each of the respective sets operate independently during low speed operation of said engine and in unison during high speed operation of said engine.
11. The valve operating means according to claim 9 in which one of said cams of said second set is a circular raised portion operative to maintain the associated exhaust valve substantially closed.
12. The valve operating means according to claim 11 in which said one cam of said second set maintains the associated exhaust valve substantially closed during low speed operation of said engine.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JPP61-200956 | 1986-08-27 | ||
| JP61200956A JPS6357806A (en) | 1986-08-27 | 1986-08-27 | Valve mechanism for internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1329077C true CA1329077C (en) | 1994-05-03 |
Family
ID=16433102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000545383A Expired - Fee Related CA1329077C (en) | 1986-08-27 | 1987-08-26 | Valve operating mechanism in an internal combustion engine |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4844022A (en) |
| EP (1) | EP0258061B1 (en) |
| JP (1) | JPS6357806A (en) |
| CA (1) | CA1329077C (en) |
| DE (1) | DE3777725D1 (en) |
Families Citing this family (31)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4964375A (en) * | 1987-12-08 | 1990-10-23 | Nissan Motor Co., Ltd. | Valve operating mechanism |
| US5123397A (en) * | 1988-07-29 | 1992-06-23 | North American Philips Corporation | Vehicle management computer |
| JPH02140407A (en) * | 1988-08-01 | 1990-05-30 | Honda Motor Co Ltd | Cylinder head structure of multiple cylinder engine |
| JPH0242108A (en) * | 1988-08-01 | 1990-02-13 | Honda Motor Co Ltd | Valve mechanism for internal combustion engine |
| JP2935237B2 (en) * | 1988-10-11 | 1999-08-16 | 本田技研工業株式会社 | Knocking control device for internal combustion engine |
| US4960094A (en) * | 1988-10-11 | 1990-10-02 | Honda Giken Kogyo Kabushiki Kaisha | Knocking control system for internal combustion engines |
| JP2816554B2 (en) * | 1989-02-07 | 1998-10-27 | 本田技研工業株式会社 | Valve train for internal combustion engine |
| US5081971A (en) * | 1989-04-07 | 1992-01-21 | Honda Giken Kogyo Kabushiki Kaisha | Intake system for internal combustion engine |
| JPH086568B2 (en) * | 1989-04-13 | 1996-01-24 | 日産自動車株式会社 | Engine valve operation control device |
| JP2736997B2 (en) * | 1989-04-27 | 1998-04-08 | 本田技研工業株式会社 | Valve drive device and valve drive method for internal combustion engine |
| JP2712544B2 (en) * | 1989-05-11 | 1998-02-16 | 日産自動車株式会社 | Valve timing control device for internal combustion engine for vehicle |
| KR960007963B1 (en) * | 1990-02-16 | 1996-06-17 | 그룹 로튜스 피엘씨 | Valve control means for internal combustion engine |
| US5253621A (en) * | 1992-08-14 | 1993-10-19 | Group Lotus Plc | Valve control means |
| GB9003603D0 (en) * | 1990-02-16 | 1990-04-11 | Lotus Group Plc | Cam mechanisms |
| JP2517078Y2 (en) * | 1990-04-13 | 1996-11-13 | 本田技研工業株式会社 | Valve train for internal combustion engine |
| JPH0811930B2 (en) * | 1990-04-13 | 1996-02-07 | 本田技研工業株式会社 | SOHC type multi-cylinder internal combustion engine |
| JP2986955B2 (en) * | 1991-04-26 | 1999-12-06 | 株式会社ユニシアジェックス | Engine Valve Actuator |
| US5331866A (en) * | 1991-06-28 | 1994-07-26 | Volkswagen Ag | Camshaft arrangement having a deactivatable cam |
| US5239885A (en) * | 1991-06-28 | 1993-08-31 | Volkswagen Ag | Camshaft with a deactivatable cam |
| JP2612788B2 (en) * | 1991-09-04 | 1997-05-21 | 本田技研工業株式会社 | Valve train for internal combustion engine |
| JP3200131B2 (en) * | 1991-10-23 | 2001-08-20 | 株式会社ユニシアジェックス | Engine Valve Actuator |
| US5239952A (en) * | 1991-11-08 | 1993-08-31 | Atsugi Unisia Corporation | Valve actuating apparatus |
| US5445116A (en) * | 1992-12-22 | 1995-08-29 | Unisia Jecs Corporation | Hydraulic variable lift engine valve gear |
| JP3358887B2 (en) * | 1994-09-20 | 2002-12-24 | 本田技研工業株式会社 | Cylinder number control internal combustion engine |
| JP4466897B2 (en) * | 2001-04-03 | 2010-05-26 | ヤマハ発動機株式会社 | High and low speed switching valve mechanism for internal combustion engine |
| US6561146B2 (en) * | 2001-07-25 | 2003-05-13 | Borgwarner, Inc. | Method of controlling resonances in internal combustion engine having variable cam timing |
| US7000581B1 (en) * | 2002-09-10 | 2006-02-21 | Nagesh S. Mavinahally | Mono-shaft four-stroke engine |
| JP5139112B2 (en) * | 2008-02-19 | 2013-02-06 | ヤマハ発動機株式会社 | engine |
| JP5139113B2 (en) | 2008-02-19 | 2013-02-06 | ヤマハ発動機株式会社 | Variable valve gear |
| US20120137995A1 (en) * | 2010-12-01 | 2012-06-07 | Kia Motors Corporation | Direct acting variable valve lift apparatus |
| JP6839576B2 (en) * | 2017-03-21 | 2021-03-10 | 本田技研工業株式会社 | DOHC type internal combustion engine |
Family Cites Families (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1003568A (en) * | 1947-01-24 | 1952-03-19 | Valve device for engine and engines with application | |
| US3168083A (en) * | 1962-10-22 | 1965-02-02 | Lucian F Buchanan | Internal combustion engine exhaust valve assembly |
| DE1526312A1 (en) * | 1963-07-23 | 1969-02-13 | Maschf Augsburg Nuernberg Ag | Multi-cylinder, air-compressing reciprocating piston engine, in particular four-stroke internal combustion engine |
| FR2448032A1 (en) * | 1979-02-05 | 1980-08-29 | Semt | PROCESS FOR IMPROVING THE EFFICIENCY OF AN INTERNAL COMBUSTION ENGINE, ESPECIALLY SUPERCHARGED |
| US4327676A (en) * | 1980-03-03 | 1982-05-04 | Mcintire Ray G | Method and apparatus for a low emission diesel engine |
| FR2493915B1 (en) * | 1980-11-13 | 1985-12-06 | Renault | VARIABLE DISTRIBUTION DEVICE FOR INTERNAL COMBUSTION ENGINE |
| FR2510182A1 (en) * | 1981-07-27 | 1983-01-28 | Renault | Adjustable engine rocker gear - has auxiliary rockers giving higher lift sliding into engagement with main rockers |
| US4584974A (en) * | 1982-07-27 | 1986-04-29 | Nissan Motor Co., Ltd. | Valve operation changing system of internal combustion engine |
| US4534323A (en) * | 1982-12-23 | 1985-08-13 | Nissan Motor Co., Ltd. | Valve operation changing system of internal combustion engine |
| US4499870A (en) * | 1983-04-26 | 1985-02-19 | Nissan Motor Company, Limited | Multi-cylinder internal combustion engine |
| AU551310B2 (en) * | 1983-06-06 | 1986-04-24 | Honda Giken Kogyo Kabushiki Kaisha | Valve actuating mechanism |
| JPS608407A (en) * | 1983-06-29 | 1985-01-17 | Honda Motor Co Ltd | Valve operation control device in intenral-combustion engine |
| US4535732A (en) * | 1983-06-29 | 1985-08-20 | Honda Giken Kogyo Kabushiki Kaisha | Valve disabling device for internal combustion engines |
| JPS6027717A (en) * | 1983-07-27 | 1985-02-12 | Honda Motor Co Ltd | Lubricator |
| US4523550A (en) * | 1983-09-22 | 1985-06-18 | Honda Giken Kogyo Kabushiki Kaisha | Valve disabling device for internal combustion engines |
| JPS60128915A (en) * | 1983-12-17 | 1985-07-10 | Honda Motor Co Ltd | Valve interrupting equipment of multi-cylinder internal-combustion engine |
| DE3523531A1 (en) * | 1984-07-02 | 1986-02-13 | Honda Giken Kogyo K.K., Tokio/Tokyo | VALVE ACTUATING DEVICE WITH LOCKING FUNCTION FOR AN INTERNAL COMBUSTION ENGINE |
| JPS6131610A (en) * | 1984-07-24 | 1986-02-14 | Honda Motor Co Ltd | Valve operation pause device for internal-combustion engine |
| JPS6131613A (en) * | 1984-07-24 | 1986-02-14 | Honda Motor Co Ltd | Valve operation pause device for internal-combustion engine |
| US4741302A (en) * | 1984-12-10 | 1988-05-03 | Mazda Motor Corporation | Internal combustion engine |
| US4627391A (en) * | 1984-12-24 | 1986-12-09 | General Motors Corporation | Engine valve train system |
| US4690110A (en) * | 1985-04-26 | 1987-09-01 | Mazda Motor Corporation | Variable valve mechanism for internal combustion engines |
| US4726332A (en) * | 1985-04-26 | 1988-02-23 | Mazda Motor Corporation | Variable valve mechanism for internal combustion engines |
| CA1284069C (en) * | 1985-07-31 | 1991-05-14 | Yoshio Ajiki | Valve operating mechanism for internal combustion engine |
| JPS62121811A (en) * | 1985-07-31 | 1987-06-03 | Honda Motor Co Ltd | Tappet valve device for interanl combustion engine |
| JP3144910B2 (en) * | 1992-10-01 | 2001-03-12 | 松下電子工業株式会社 | Discharge lamp |
| JPH06181510A (en) * | 1992-12-11 | 1994-06-28 | Fuji Photo Film Co Ltd | Method and device for picture processing |
-
1986
- 1986-08-27 JP JP61200956A patent/JPS6357806A/en active Granted
-
1987
- 1987-08-26 CA CA000545383A patent/CA1329077C/en not_active Expired - Fee Related
- 1987-08-27 US US07/089,973 patent/US4844022A/en not_active Expired - Lifetime
- 1987-08-27 EP EP87307616A patent/EP0258061B1/en not_active Expired - Lifetime
- 1987-08-27 DE DE8787307616T patent/DE3777725D1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0258061B1 (en) | 1992-03-25 |
| US4844022A (en) | 1989-07-04 |
| JPH0323723B2 (en) | 1991-03-29 |
| DE3777725D1 (en) | 1992-04-30 |
| EP0258061A1 (en) | 1988-03-02 |
| JPS6357806A (en) | 1988-03-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |