EP0695395B1 - Valve control means - Google Patents
Valve control means Download PDFInfo
- Publication number
- EP0695395B1 EP0695395B1 EP94910474A EP94910474A EP0695395B1 EP 0695395 B1 EP0695395 B1 EP 0695395B1 EP 94910474 A EP94910474 A EP 94910474A EP 94910474 A EP94910474 A EP 94910474A EP 0695395 B1 EP0695395 B1 EP 0695395B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cam
- follower
- valve
- follower means
- valve control
- 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 - Lifetime
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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
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0036—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
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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
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
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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
- F01L1/14—Tappets; Push rods
- F01L1/143—Tappets; Push rods for use with overhead camshafts
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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
- F01L1/20—Adjusting or compensating clearance
- F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
- F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
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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
- F01L1/20—Adjusting or compensating clearance
- F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
- F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
- F01L1/245—Hydraulic tappets
- F01L1/25—Hydraulic tappets between cam and valve stem
Definitions
- the present invention relates to valve control means for an internal combustion engine.
- valve control means of the present invention will be described by reference to use of the valve control means in the internal combustion engine of an automobile, but the invention should not be considered limited to such use.
- valve control means for controlling the inlet and exhaust valves of an internal combustion engine.
- a camshaft having a first cam and a second cam having a different cam profile from the first cam.
- Means are provided for relaying the camming action of the cams to an inlet or exhaust valve of the engine.
- the means for transmitting the reciprocating movement comprises a first cam follower member which engages an inlet or exhaust valve and a second cam follower member which is moveable relative to the first cam follower member and locking means which can link the two cam follower members to move together.
- the locking means of the system described in WO91/12413 is operable under the control of hydraulic pressure.
- the locking means is controlled so that the lift of the controlled valve is controlled by the cam profile of one of the cams at low engine speeds and by the cam profile of the other cam at high engine speeds.
- the valve control means described in WO91/12413 includes a hydraulic lash adjuster.
- Hydraulic lash adjusters are well known in the art and are used to compensate for wear of components in the valve drive trains.
- a hydraulic lash adjuster will expand to ensure that the components of the valve control means remain in contact with each other despite wear.
- valve control means There are tight constraints on the packaging of valve control means in modern day engines. This is particularly the case in engines which use four valves per cylinder. For this reason, valve control means used should be kept as small as possible.
- the first cam follower member of the valve control means of WO91/12413 is a bucket tappet slidable in a bore provided in the second cam follower member. Bucket tappets are well known in prior art engines. In the system of WO91/12413 the hydraulic lash adjuster acts between the bucket tappet and the controlled valve, with the stem of the controlled valve directly abutting the hydraulic lash adjuster. A more detailed description of the valve control means of WO91/12413 will be given later with reference to one of the drawings of this application.
- Bucket tappets used in conventional engines are of a diameter typically in the range 19mm to 40 mm.
- the tappets must be of such a size to give the required mechanical advantage for the cam profiles used in conventional engines.
- Mechanical advantage is gained by distancing the point of contact between the tappet and the lift portion of the cam from the central axis of the tappet.
- a minimum distance must be allowed and thus a minimum area of tappet provided. There is thus a geometrical relationship between the lift velocity of a cam profile and the area of tappet used.
- hydraulic lash adjusters are known in which one of the components which defines the expandable chamber for hydraulic fluid directly abuts a cam and the other component which defines the chamber is connected to a push rod.
- a lash adjuster has never to the applicant's knowledge been used in an overhead camshaft engine and furthermore the lash adjusters used to date in the push-rod engines have typically had an external diameter of 19mm or above since they are required to have a minimum area by the cam profiles used in the push-rod engines.
- the present invention provides valve control means for use in an overhead camshaft internal combustion engine which has a poppet valve, cam means comprising a rotatable camshaft having a first portion and a second portion having a different cross-section from the first portion, the valve control means comprising first follower means engageable with the poppet valve and engageable with the first portion, which first follower means comprises hydraulic lash adjuster means having a first member which defines a closed bore, a second member movable in the bore of the first member and defining with the first member a variable volume chamber for hydraulic fluid, conduit means for allowing flow of fluid to the chamber and check valve means for controlling the flow of fluid to the chamber, second follower means movable relative to the first follower means and engageable with the second portion, said second follower means defining a bore wherein the first follower means is located with at least a portion of the first member of the hydraulic lash adjuster means being slidable in the bore, and linking means to enable the first and second follower means to be linked together, wherein in use
- one of the follower members of the present invention is designed to be driven by a low lift cam (or no lift lobe as will be described later) designed for low speed operation, the area of the follower member engaging the cam can be reduced.
- the bucket tappet of WO91/12413 is no longer needed and the valve control means can be reduced in size.
- valve control means of WO91/12413 could be used in certain existing engines which have bucket tappets and hydraulic lash adjusters, the valve control means being simply positioned in the bores provided in the engine for the bucket tappets and the hydraulic lash adjusters.
- the valve control means of WO91/12413 could only be installed in a restricted range of such engines because of the overall size of the valve control means. Since the valve control means of the present invention can be made smaller than the valve control means of W091/12413, the valve control means can be installed in a greater range of engines.
- first and second follower means are cylindrical and the first follower means has a diameter in the range of 8 to 18mm.
- the bucket tappets of the prior art typically have diameters in the range of 19 to 40mm.
- the first follower means is thus of a first diameter and the second follower means of a second larger diameter. Both diameters must at least be of a certain minimum to allow for the lifts of the first and second cams (if two cams are used). However in operation, the first follower means will engage a cam of lower lift (or a lobe of no lift as will be described later) than the second follower means and thus the first diameter can be smaller than the second diameter.
- the present invention also has the advantage that the valve drivetrain can be made lighter since a bucket tappet is not included in the valve drivetrain.
- the engagement means comprises a recess in the exterior surface of the first member of the hydraulic lash adjuster means and the linking means comprises a locking pin in the second follower means and extendable from the second follower means to engage the recess.
- the first portion of the cam shaft is a first cam having a first cam profile
- the second portion of the camshaft is a second cam having a second cam profile different to the first cam profile
- the first follower means comprises first cam follower means engageable with the first cam
- the second follower means comprises second cam follower means engageable with the second cam.
- the first portion of the camshaft can be a portion of circular cross-section which imparts no lift to valve means
- the second portion of the camshaft is a cam
- the second follower means comprises second cam follower means engageable with the cam.
- the present invention also provides an internal combustion engine having valve control means as previously described wherein a wear surface is provided on an exterior surface of the first member of the hydraulic lash adjuster means and the wear surface directly abuts the first portion of the camshaft.
- the hydraulic lash adjuster means abuts a bucket tappet which then abuts a portion of a camshaft. This followed the accepted practice of providing bucket tappets with hydraulic lash adjusters located within. The present invention breaks away from accepted practice.
- valve control means such as the valve control means described in WO91/12413
- the hydraulic lash adjuster means can directly abut a portion of a camshaft (without the interposition of a bucket tappet) and therefore the valve control means can be of an overall diameter which is appreciably smaller than the diameter of the valve control means of the prior art.
- FIG. 1 a camshaft 10 having a first cam 11 of a first cam profile and two further cam members 12 and 13 each having the same cam profile, the cam profile being different to the cam profile of the cam 11.
- the figure 1 illustrates the valve control means of the prior art in a first operating condition, in which an inlet valve 14 is controlled by the profile of the cam 11.
- Valve control means 15 of the prior art system can be seen in figure 1 to comprise an outer cam follower member 16 which takes the form of a cylinder and an inner cam follower member 17 which is slidable within a bore of the outer cam follower member 16.
- the inner cam follower member 17 comprises a bucket tappet 18, well known in the prior art.
- a hydraulic lash adjuster comprising members 19 and 20 is located within the bucket tappet 18.
- the member 20 abuts the top of the inlet valve 14 and has a portion of an external diameter which corresponds to the internal diameter of the bucket tappet 18.
- the member 19 abuts the bucket tappet 18 and is slidable within the member 20.
- the members 19 and 20 define cetween them a chamber and a check valve is provided to control flow of fluid into the chamber. Fluid can be admitted into the chamber, but the check valve prevents fluid from flowing from the chamber.
- the members 20 and 19 move relative to each other to expand the chamber defined between them to compensate for wear in the components of the valve control mechanism, eg. wear of the cam member 11, follower member 18 or valve 14.
- the inner cam member thus comprises a bucket tappet 18 and a hydraulic lash adjuster located to act between the bucket tappet 18 and the valve 14.
- valve control means according to the present invention.
- the valve control means according to the present invention comprise a first cam follower member 100 which is movable in a bore provided in a second cam follower member 150.
- the first cam follower member 100 provides hydraulic lash adjustment.
- the first cam follower member 100 comprises an upper member 101 which provides a wear surface for engaging a cam.
- the upper member 101 in figure 2 is formed of two parts 101A and 101B which are attached to each other. Part 101A will typically be made of alloy cast iron and part 101B will typically be made of steel.
- the upper member 101 is generally cylindrical in form. There is an upper cavity 102 provided in the member 101 which communicates with the exterior of the member 101 via a passage 103. The cavity 102 is also in communication with the engagement surface of the member 101 via a passage 104. The cavity 102 is cylindrical and at the lower end of the cavity 102 there is provided a passage 106 leading downwardly from the cavity 102.
- the member 101 also has a lower cavity which is of greater diameter than the upper cavity 102. In the lower cavity a lower member 107 of the first cam follower member 100 is slidable relative to the member 101.
- the lower member 107 and the upper member 101 define between them a chamber 108.
- the chamber 108 can communicate with the chamber 102 via the passage 106.
- Check valve means are provided to control the flow of fluid through the passage 106.
- the check valve means comprise a valve retainer 109, a ball 110, a light spring 111 acting between the ball 110 and the valve retainer 109 and a spring 112 acting between the upper member 101 and the lower member 107.
- the lower member 107 of the first cam follower means 100 has an external diameter which corresponds to the diameter of the lower cavity of the upper member 101.
- the second cam follower means 150 comprises a first member 151 which provides a surface which is engageable by a cam.
- the member 151 is generally cylindrical in nature and will typically be made of cast iron alloy.
- Attached to the member 151 is a skirt 152 typically made of steel, again of a generally cylindrical nature.
- the outer diamater of the outer steel skirt 152 corresponds to the greatest diameter of the member 151.
- the skirt 152 has a portion of reduced diameter which defines an annular recess 154.
- the portion of reduced diameter also defines an annular seat 155 engageable by a spring.
- annular cavity 156 communicates with the annular recess 154 via passages 157.
- Locking pins 160, 161 and 162 can be seen in figure 3. Locking pin 160 can also be seen in figure 2.
- the locking pins 160, 161 and 162 are identical to each other and are mounted in the member 151 in identical fashion. Therefore, we will only discuss in detail the locking pin 160.
- the locking pin 160 is slidable in a radially extending bore in the member 151.
- a spring 163 is provided to act between an increased diameter portion of the locking pin 160 and the member 151, to bias the locking pin 160 radially outwardly.
- the locking pin 160 is biased by the spring 163 into abutment with the steel skirt 152. Since the rear portion of the locking pin 160 is flat whilst the inner surface of the skirt 152 is cylindrical, a cavity 167 is maintained between the locking pin 160 and the skirt 152 even when the locking pin 160 abuts the skirt 152.
- a passage 164 is provided in the member 151 to allow communication between the cavity 167 and the cavity 156.
- the locking pin 160 is designed to slide radially in the bore in the member 151 to engage a recess 165 defined in the exterior surface of the member 101 of the first cam follower means.
- a bore 166 is provided through the locking pin 160 to allow communication between the recess 165 and the cavity defined between the locking pin 160 and the member 151.
- a groove 168 is provided on the surface of the member 101 to allow communication of the recess 165 via a passage 170 with the bottom surface of the member 101.
- a pin 149 is provided to extend inwardly from the cam follower means 150 to engage a groove 148 which extends axially down the cam follower means 100.
- the pin 149 prevents relative rotation between the cam follower means 100 and 150.
- valve control means can be seen in use in an internal combustion engine in figures 4 and 5.
- FIG 4 the low speed operation of the internal combustion engine is shown.
- an inlet valve 180 of a cylinder of an internal combustion engine There can also be seen three cams 181, 182 and 183 provided on a camshaft 185 for rotation therewith.
- the cam 181 has a first low lift cam profile and the cams 182 and 183 each have the same high lift cam profile.
- the inlet valve 180 is a poppet valve provided with a spring retainer 186.
- a valve spring 187 acts between the spring retainer 136 and the cylinder head of the engine shown generally at 188. The spring 187 acts to bias the poppet valve 180 into its valve seat 189.
- the valve control means of the invention is provided in a bore in the cylinder head 188, and is slidable in the bore.
- An oil gallery 190 is provided in the cylinder head 188, which communicates with the annular recess 154 of member 152 when the valve control means is located in the bore.
- a spring 192 is provided to act between the spring seat 155 of the valve control means and the cylinder head 188 and the spring 192 biases the second cam follower member 150 into abutment with the two cams 182 and 183.
- the oil pressure in oil gallery 190 is kept at a low level.
- the fluid pressure is communicated from the oil gallery 190 via the recess 154 of the valve control means to the annular cavity 156 of the valve control means.
- the fluid pressure is then relayed by the passages 164 to the cavities 167 defined behind the locking pins (locking pin 160 being shown in the figure).
- the low oil pressure is insufficient to overcome the biasing effect of the spring 163 and therefore the locking pin 160 (and the other locking pins 161 and 162) remain retracted within the cam follower member 150 and the cam follower member 150 is not linked in any way to the cam follower member 100.
- cam follower members 100 and 150 are not linked, they move independently of each other.
- the cam follower member 100 engages the surface of the cam 181 and will transmit the camming action of the cam 181 to the inlet valve 180. This imparts to the valve 180 a lift A shown in figure 4.
- Control means will be provided in the internal combustion engines to control the pressure of the fluid in the oil gallery 190.
- the control means will typically switch the oil pressure from a low pressure to a high pressure when a particular engine speed is reached.
- the pressure in the oil gallery 190 has been switched to a high pressure and the high pressure oil has been communicated to act on the locking pins 160, 161 and 162, which have engaged the inner cam follower member 100 and have linked the cam follower members 100 and 150, so that they move together.
- the inlet valve 180 is thus controlled by the profile of the cams 182 and 183, which is a higher lift profile than the profile of the cam 181.
- the increased lift of the valve is indicated at B in the figure 5.
- cams 182 and 183 have a higher lift than cam 181, the inner cam follower member 100 will not engage the cam 181 whilst the cam follower member 150 engages the high lift portions of the cams 182 and 183. This can be seen in figure 5.
- the hydraulic lash adjustment means of the invention is supplied with oil in both operating conditions when the cam follower members 100 and 150 engage the base circle portions of the cams 182, 181 and 183.
- the spring 112 acts to push the member 107 away from the member 101 and to draw oil into the bottom chamber 108 from the top chamber 102 via the passage 106.
- the spring 112 is of greater resilience than the light spring 111 which merely serves to locate the ball 110 adjacent to the passage 106.
- the member 107 can only move away from the member 101, since the ball 110 will act to stop fluid flowing from the chamber 108 into the chamber 102 when a compressive force is applied on the two members 101 and 107.
- the chamber 102 is supplied with hydraulic fluid via the passages 103 and passages 179 with the fluid being supplied from the cavity 156 which is in turn supplied through passage 157 and annular cavity 154 from the oil gallery 190.
- the passage 104 serves to allow a fluid to flow from the chamber 102 to the top surface of the cam follower members 100 and 150, the hydraulic fluid then lubricating the cam follower surfaces and minimising wear and preventing air being trapped in cavity 102.
- the hydraulic lash adjustment means of the invention has advantageous features not present in the hydraulic lash adjustment means of the prior art since it does not require a bucket tappet and therefore allows the valve control means of the present invention to be smaller than the valve control means of the prior art.
- one of the members which defines the variable volume chamber of the hydraulic lash adjuster has a wear surface which is engageable directly with a cam (or with a rocker arm positioned between the cam and the follower member, as seen in one embodiment of WO91/12413).
- the member has a recess defined on its exterior surface which can be engaged by locking pins.
- the diameter of the bore of the external cam follower means 151 can be reduced in comparison to the bores of the prior art valve control means since the bore does not have to accomodate a bucket tappet.
- the cross-sectional area of the bore can be as small as the cross-sectional area of the largest part of the largest of two members which define the expandable chamber of the hydraulic lash adjuster.
- FIG. 6 a second preferred embodiment of the invention can be seen.
- the second preferred embodiment is in most respects identical to the first preferred embodiment and like components have been given similar reference numerals with the prefix 200 being used instead of the prefix 100.
- the second cam follower member 250 has a slightly different shape, but remains generally cylindrical.
- An inner steel skirt 230 is provided in the second embodiment, which is attached to the body 251 of the cam follower member 250 and which is also attached at its lower end to the outer steel skirt 255.
- the locking pins 260, 261 and 262 are of an L-shape in cross-section.
- Springs 263 are provided to act between the lower portion of the locking pins and the inner steel skirt 230.
- Apertures such as 278 are provided in the inner steel skirt to prevent hydraulic locks by allowing the cavities defined around the springs 263 to be vented to a groove 229 running axially along the exterior of the cam follower member 200.
- the locking pin 260 can be seen to have a groove 228 on the top surface thereof.
- the groove 228 allows fluid to flow from the recess 265 provided on the exterior of the cam follower member 200 to the groove 229 which allows the fluid to flow to the top surface of the cam follower members.
- FIGS 8 and 9 a third preferred embodiment of the invention can be seen.
- the third preferred embodiment is very similar to the second preferred embodiment already described and only differences will be discussed.
- the first important difference between the second and third embodiments is that the third embodiment uses only two locking pins 360 and 361.
- the locking pins 360 and 361 are again of an L-shaped cross-section.
- the venting of the cavities surrounding the biasing springs 363 is provided for in a different manner in the third embodiment.
- the locking pins 360 and 361 each have a tapered portion at the front end thereof and a passage running through the locking pins which allows the cavities surrounding the springs 363 to communicate with the recesses 365 defined on the exterior of the cam follower member 300.
- the tapered portions of the locking pins 360 and 361 also allow fluid to flow from the recesses 365 through grooves such as grooves 368 defined on the exterior of the cam follower member 300. The grooves relay the oil to the top surfaces of the cam follower members 300 and 350.
- valve control means are designed to be free to rotate within a bore in a cylinder head, thereby reducing wear by allowing the cams to act on different portions of the surfaces of the cam follower members.
- the inner cam follower member comprises a hydraulic lash adjuster which engages a cam without the need for a bucket tappet.
- the inner cam follower means can be reduced in diameter from those of the prior art, with a corresponding reduction in the overall diameter of the valve control means. This is very important to meet packaging constraints within an engine.
- the low lift cam can be replaced by a lobe of circular cross-section such that at low engine speeds the valve can be deactivated (the circular lobe imparting no lift).
- the locking pin arrangement when interlocking the inner and outer cam follower members will allow some downward movement of the outer cam follower member from its position in engagement with the base circles of the two cams engaged thereby to a position in which it starts to move the inner cam follower member downwardly.
- This can be achieved by suitable sizing of the recess in the exterior of the inner member.
- This feature allows for misalignment created by wear and ensures that the force of the valve spring is transmitted to the base circle portion of the low lift cam (or no lift lobe) at low and high engine speeds.
- the hydraulic lash adjuster thus adjusts for wear of the most worn component (the low lift cam or no lift lobe) in all conditions. This arrangement ensures that the valve is returned to its valve seat securely at low and high engine speeds, despite differences in wear between the cams of the camshaft (or the no lift lobe and the cam of the camshaft).
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Abstract
Description
- The present invention relates to valve control means for an internal combustion engine.
- The valve control means of the present invention will be described by reference to use of the valve control means in the internal combustion engine of an automobile, but the invention should not be considered limited to such use.
- In WO91/12413 there is described valve control means for controlling the inlet and exhaust valves of an internal combustion engine. In each of the illustrated embodiments of the specification there is shown a camshaft having a first cam and a second cam having a different cam profile from the first cam. Means are provided for relaying the camming action of the cams to an inlet or exhaust valve of the engine. The means for transmitting the reciprocating movement comprises a first cam follower member which engages an inlet or exhaust valve and a second cam follower member which is moveable relative to the first cam follower member and locking means which can link the two cam follower members to move together. When the first and second cam follower members are not linked the camming action of the first cam is transmitted by the first cam follower member to the controlled valve, the lift of the valve following the profile of the first cam. When the first and second cam follower members are linked together the camming action of the second cam is relayed to the controlled valve via both of the first and second cam follower members, the lift of the controlled valve being controlled by the profile of the second cam.
- The locking means of the system described in WO91/12413 is operable under the control of hydraulic pressure. The locking means is controlled so that the lift of the controlled valve is controlled by the cam profile of one of the cams at low engine speeds and by the cam profile of the other cam at high engine speeds. This gives an advantage over the previously known engines, because the relationship between valve lift and crankshaft position can be varied at different engine speeds to optimise engine efficiency.
- The valve control means described in WO91/12413 includes a hydraulic lash adjuster. Hydraulic lash adjusters are well known in the art and are used to compensate for wear of components in the valve drive trains. A hydraulic lash adjuster will expand to ensure that the components of the valve control means remain in contact with each other despite wear.
- There are tight constraints on the packaging of valve control means in modern day engines. This is particularly the case in engines which use four valves per cylinder. For this reason, valve control means used should be kept as small as possible.
- The first cam follower member of the valve control means of WO91/12413 is a bucket tappet slidable in a bore provided in the second cam follower member. Bucket tappets are well known in prior art engines. In the system of WO91/12413 the hydraulic lash adjuster acts between the bucket tappet and the controlled valve, with the stem of the controlled valve directly abutting the hydraulic lash adjuster. A more detailed description of the valve control means of WO91/12413 will be given later with reference to one of the drawings of this application.
- Bucket tappets used in conventional engines are of a diameter typically in the range 19mm to 40 mm. The tappets must be of such a size to give the required mechanical advantage for the cam profiles used in conventional engines. Mechanical advantage is gained by distancing the point of contact between the tappet and the lift portion of the cam from the central axis of the tappet. To achieve the acceleration of the valve required by a cam profile suitable for all speed or high speed engine operation of an engine a minimum distance must be allowed and thus a minimum area of tappet provided. There is thus a geometrical relationship between the lift velocity of a cam profile and the area of tappet used.
- In certain push-rod engines, hydraulic lash adjusters are known in which one of the components which defines the expandable chamber for hydraulic fluid directly abuts a cam and the other component which defines the chamber is connected to a push rod. However, such a lash adjuster has never to the applicant's knowledge been used in an overhead camshaft engine and furthermore the lash adjusters used to date in the push-rod engines have typically had an external diameter of 19mm or above since they are required to have a minimum area by the cam profiles used in the push-rod engines.
- The present invention provides valve control means for use in an overhead camshaft internal combustion engine which has a poppet valve, cam means comprising a rotatable camshaft having a first portion and a second portion having a different cross-section from the first portion, the valve control means comprising first follower means engageable with the poppet valve and engageable with the first portion, which first follower means comprises hydraulic lash adjuster means having a first member which defines a closed bore, a second member movable in the bore of the first member and defining with the first member a variable volume chamber for hydraulic fluid, conduit means for allowing flow of fluid to the chamber and check valve means for controlling the flow of fluid to the chamber, second follower means movable relative to the first follower means and engageable with the second portion, said second follower means defining a bore wherein the first follower means is located with at least a portion of the first member of the hydraulic lash adjuster means being slidable in the bore, and linking means to enable the first and second follower means to be linked together, wherein in use of the valve control means, when the first and second follower means are not linked the motion of the poppet valve is controlled by the first follower means and the poppet valve is given in each engine cycle the lift of the first portion, when the first and second follower means are linked the motion of the poppet valve is controlled by the second follower means and the poppet valve is given in each engine cycle the lift of the second portion, characterised in that the cross section of the bore defined in said second follower means matches in shape and size the cross-section of the portion of the first member of the hydraulic lash adjuster means slidable in the bore, the second member of the hydraulic lash adjuster abuts the poppet valve, and engagement means is provided on the exterior surface of the first member of the hydraulic lash adjuster means, the engagement means enabling the linking means to link together the first and second follower means.
- The applicant has realised that since one of the follower members of the present invention is designed to be driven by a low lift cam (or no lift lobe as will be described later) designed for low speed operation, the area of the follower member engaging the cam can be reduced. Thus the bucket tappet of WO91/12413 is no longer needed and the valve control means can be reduced in size.
- The valve control means of WO91/12413 could be used in certain existing engines which have bucket tappets and hydraulic lash adjusters, the valve control means being simply positioned in the bores provided in the engine for the bucket tappets and the hydraulic lash adjusters. However, the valve control means of WO91/12413 could only be installed in a restricted range of such engines because of the overall size of the valve control means. Since the valve control means of the present invention can be made smaller than the valve control means of W091/12413, the valve control means can be installed in a greater range of engines.
- Preferably the first and second follower means are cylindrical and the first follower means has a diameter in the range of 8 to 18mm. The bucket tappets of the prior art typically have diameters in the range of 19 to 40mm.
- The first follower means is thus of a first diameter and the second follower means of a second larger diameter. Both diameters must at least be of a certain minimum to allow for the lifts of the first and second cams (if two cams are used). However in operation, the first follower means will engage a cam of lower lift (or a lobe of no lift as will be described later) than the second follower means and thus the first diameter can be smaller than the second diameter.
- The present invention also has the advantage that the valve drivetrain can be made lighter since a bucket tappet is not included in the valve drivetrain.
- Preferably the engagement means comprises a recess in the exterior surface of the first member of the hydraulic lash adjuster means and the linking means comprises a locking pin in the second follower means and extendable from the second follower means to engage the recess.
- Preferably the first portion of the cam shaft is a first cam having a first cam profile, the second portion of the camshaft is a second cam having a second cam profile different to the first cam profile, the first follower means comprises first cam follower means engageable with the first cam and the second follower means comprises second cam follower means engageable with the second cam.
- Alternatively, the first portion of the camshaft can be a portion of circular cross-section which imparts no lift to valve means, the second portion of the camshaft is a cam and the second follower means comprises second cam follower means engageable with the cam.
- The present invention also provides an internal combustion engine having valve control means as previously described wherein a wear surface is provided on an exterior surface of the first member of the hydraulic lash adjuster means and the wear surface directly abuts the first portion of the camshaft.
- In engines using the valve control means of W091/12413, the hydraulic lash adjuster means abuts a bucket tappet which then abuts a portion of a camshaft. This followed the accepted practice of providing bucket tappets with hydraulic lash adjusters located within. The present invention breaks away from accepted practice.
- The present invention is therefore advantageous over valve control means such as the valve control means described in WO91/12413, because the hydraulic lash adjuster means can directly abut a portion of a camshaft (without the interposition of a bucket tappet) and therefore the valve control means can be of an overall diameter which is appreciably smaller than the diameter of the valve control means of the prior art.
- Preferred embodiments of the present invention will now be discussed with reference to the accompanying drawings in which:-
- Figure 1 shows prior art valve control means;
- Figure 2 shows a cross-section of a first embodiment of valve control means according to the invention, the cross-section being taken along the line BB of Figure 3, in the direction of the arrows shown;
- Figure 3 shows a cross-section of the valve control means of the first embodiment shown in Figure 2, the cross-section being taken along the line AA shown in Figure 2, in the direction of the arrows shown;
- Figure 4 shows a cross-sectional view of the valve control means of the first embodiment in use in an internal combustion engine in a first operating condition;
- Figure 5 shows a cross-section of valve control means according to the first embodiment of the invention in use in an internal combustion engine in a second operating condition;
- Figure 6 shows a cross-section of a second embodiment of valve control means according to the present invention, the cross-section being taken along the lines DD of Figure 7, in the direction of the arrows shown;
- Figure 7 shows a cross-section of the second embodiment shown in Figure 6, the cross-section being taken along the lines CC of the Figure 6, in the direction of the arrows shown;
- Figure 8 shows a cross-section of a third embodiment of valve control means according to the invention, taken along the line FF shown in figure 9, in the direction of the arrows shown;
- Figure 9 shows a cross-section of the third embodiment shown in figure 8 taken along the line EE shown in figure 8, in the direction of the arrows shown.
- Turning first to describe the prior art valve control means, as shown in WO91/12413, there can be seen in figure 1 a
camshaft 10 having a first cam 11 of a first cam profile and twofurther cam members 12 and 13 each having the same cam profile, the cam profile being different to the cam profile of the cam 11. - The figure 1 illustrates the valve control means of the prior art in a first operating condition, in which an
inlet valve 14 is controlled by the profile of the cam 11. - Valve control means 15 of the prior art system can be seen in figure 1 to comprise an outer
cam follower member 16 which takes the form of a cylinder and an innercam follower member 17 which is slidable within a bore of the outercam follower member 16. - In the prior art embodiment the inner
cam follower member 17 comprises a bucket tappet 18, well known in the prior art. A hydraulic lashadjuster comprising members - The
member 20 abuts the top of theinlet valve 14 and has a portion of an external diameter which corresponds to the internal diameter of the bucket tappet 18. Themember 19 abuts the bucket tappet 18 and is slidable within themember 20. In a known manner, themembers members follower member 18 orvalve 14. - It should be appreciated that the inner cam member thus comprises a
bucket tappet 18 and a hydraulic lash adjuster located to act between thebucket tappet 18 and thevalve 14. - Referring now to figure 2 there can be seen valve control means according to the present invention. The valve control means according to the present invention comprise a first
cam follower member 100 which is movable in a bore provided in a secondcam follower member 150. - The first
cam follower member 100 provides hydraulic lash adjustment. The firstcam follower member 100 comprises anupper member 101 which provides a wear surface for engaging a cam. Theupper member 101 in figure 2 is formed of twoparts 101A and 101B which are attached to each other.Part 101A will typically be made of alloy cast iron and part 101B will typically be made of steel. - The
upper member 101 is generally cylindrical in form. There is anupper cavity 102 provided in themember 101 which communicates with the exterior of themember 101 via apassage 103. Thecavity 102 is also in communication with the engagement surface of themember 101 via apassage 104. Thecavity 102 is cylindrical and at the lower end of thecavity 102 there is provided apassage 106 leading downwardly from thecavity 102. - The
member 101 also has a lower cavity which is of greater diameter than theupper cavity 102. In the lower cavity alower member 107 of the firstcam follower member 100 is slidable relative to themember 101. - The
lower member 107 and theupper member 101 define between them achamber 108. Thechamber 108 can communicate with thechamber 102 via thepassage 106. Check valve means are provided to control the flow of fluid through thepassage 106. The check valve means comprise avalve retainer 109, aball 110, alight spring 111 acting between theball 110 and thevalve retainer 109 and aspring 112 acting between theupper member 101 and thelower member 107. - The
lower member 107 of the first cam follower means 100 has an external diameter which corresponds to the diameter of the lower cavity of theupper member 101. - The second cam follower means 150 comprises a
first member 151 which provides a surface which is engageable by a cam. Themember 151 is generally cylindrical in nature and will typically be made of cast iron alloy. Attached to themember 151 is askirt 152 typically made of steel, again of a generally cylindrical nature. The outer diamater of theouter steel skirt 152 corresponds to the greatest diameter of themember 151. - The
skirt 152 has a portion of reduced diameter which defines anannular recess 154. The portion of reduced diameter also defines anannular seat 155 engageable by a spring. - Between the
member 151 and theskirt 152 there is defined anannular cavity 156. Theannular cavity 156 communicates with theannular recess 154 viapassages 157. - Locking pins 160, 161 and 162 can be seen in figure 3. Locking
pin 160 can also be seen in figure 2. The locking pins 160, 161 and 162 are identical to each other and are mounted in themember 151 in identical fashion. Therefore, we will only discuss in detail thelocking pin 160. - The
locking pin 160 is slidable in a radially extending bore in themember 151. Aspring 163 is provided to act between an increased diameter portion of thelocking pin 160 and themember 151, to bias thelocking pin 160 radially outwardly. Thelocking pin 160 is biased by thespring 163 into abutment with thesteel skirt 152. Since the rear portion of thelocking pin 160 is flat whilst the inner surface of theskirt 152 is cylindrical, a cavity 167 is maintained between the lockingpin 160 and theskirt 152 even when thelocking pin 160 abuts theskirt 152. Apassage 164 is provided in themember 151 to allow communication between the cavity 167 and thecavity 156. - The
locking pin 160 is designed to slide radially in the bore in themember 151 to engage arecess 165 defined in the exterior surface of themember 101 of the first cam follower means. - A
bore 166 is provided through thelocking pin 160 to allow communication between therecess 165 and the cavity defined between the lockingpin 160 and themember 151. Agroove 168 is provided on the surface of themember 101 to allow communication of therecess 165 via a passage 170 with the bottom surface of themember 101. - A
pin 149 is provided to extend inwardly from the cam follower means 150 to engage agroove 148 which extends axially down the cam follower means 100. Thepin 149 prevents relative rotation between the cam follower means 100 and 150. - The first preferred embodiment of the valve control means can be seen in use in an internal combustion engine in figures 4 and 5.
- In figure 4, the low speed operation of the internal combustion engine is shown. In the figure there can be seen an
inlet valve 180 of a cylinder of an internal combustion engine. There can also be seen threecams camshaft 185 for rotation therewith. Thecam 181 has a first low lift cam profile and thecams - The
inlet valve 180 is a poppet valve provided with aspring retainer 186. Avalve spring 187 acts between the spring retainer 136 and the cylinder head of the engine shown generally at 188. Thespring 187 acts to bias thepoppet valve 180 into itsvalve seat 189. - The valve control means of the invention is provided in a bore in the
cylinder head 188, and is slidable in the bore. Anoil gallery 190 is provided in thecylinder head 188, which communicates with theannular recess 154 ofmember 152 when the valve control means is located in the bore. - A
spring 192 is provided to act between thespring seat 155 of the valve control means and thecylinder head 188 and thespring 192 biases the secondcam follower member 150 into abutment with the twocams - In the operating condition shown in the figure 4, the oil pressure in
oil gallery 190 is kept at a low level. The fluid pressure is communicated from theoil gallery 190 via therecess 154 of the valve control means to theannular cavity 156 of the valve control means. The fluid pressure is then relayed by thepassages 164 to the cavities 167 defined behind the locking pins (lockingpin 160 being shown in the figure). The low oil pressure is insufficient to overcome the biasing effect of thespring 163 and therefore the locking pin 160 (and the other locking pins 161 and 162) remain retracted within thecam follower member 150 and thecam follower member 150 is not linked in any way to thecam follower member 100. - Since the
cam follower members cam follower member 100 engages the surface of thecam 181 and will transmit the camming action of thecam 181 to theinlet valve 180. This imparts to the valve 180 a lift A shown in figure 4. - Control means will be provided in the internal combustion engines to control the pressure of the fluid in the
oil gallery 190. The control means will typically switch the oil pressure from a low pressure to a high pressure when a particular engine speed is reached. In figure 5, the pressure in theoil gallery 190 has been switched to a high pressure and the high pressure oil has been communicated to act on the locking pins 160, 161 and 162, which have engaged the innercam follower member 100 and have linked thecam follower members inlet valve 180 is thus controlled by the profile of thecams cam 181. The increased lift of the valve is indicated at B in the figure 5. Since thecams cam 181, the innercam follower member 100 will not engage thecam 181 whilst thecam follower member 150 engages the high lift portions of thecams - When the engine speed returns below the chosen level, the pressure in the
oil gallery 190 will be returned to a low level and thesprings 163 will move the locking pins 160, 161 and 162 out of engagement with the innercam follower member 100, so that thecam follower members valve 180 is again controlled by the profile of thecam 181. - Engagement of the locking pins with the inner
cam follower member 100 can only occur when the cam follower means 100 and 150 are in alignment during the base circle portions of thecams cam follower member 100, the locking pins can only be retracted while the cam follower members engage the base circle portion of thecams - When the locking pins 160, 161 and 162 are moved radially inwardly under fluid pressure, it is important to ensure that a hydraulic lock does not occur due to fluid trapped between the locking pins and the
cam follower member 150. This is prevented in the first preferred embodiment of the invention described above by the provision of thepassage 166 which allows fluid to flow out of the chamber defined between the lockingpin 160 and thecam follower member 150 when thelocking pin 160 is moving radially inwardly. The fluid flows from the chamber through thepassage 166 into therecess 165 defined on the exterior of the innercam follower member 101 and from therecess 165 down thegroove 168. - The hydraulic lash adjustment means of the invention is supplied with oil in both operating conditions when the
cam follower members cams valve 180 wears, thespring 112 acts to push themember 107 away from themember 101 and to draw oil into thebottom chamber 108 from thetop chamber 102 via thepassage 106. It will be appreciated that thespring 112 is of greater resilience than thelight spring 111 which merely serves to locate theball 110 adjacent to thepassage 106. Themember 107 can only move away from themember 101, since theball 110 will act to stop fluid flowing from thechamber 108 into thechamber 102 when a compressive force is applied on the twomembers - The
chamber 102 is supplied with hydraulic fluid via thepassages 103 andpassages 179 with the fluid being supplied from thecavity 156 which is in turn supplied throughpassage 157 andannular cavity 154 from theoil gallery 190. - The
passage 104 serves to allow a fluid to flow from thechamber 102 to the top surface of thecam follower members cavity 102. - The hydraulic lash adjustment means of the invention has advantageous features not present in the hydraulic lash adjustment means of the prior art since it does not require a bucket tappet and therefore allows the valve control means of the present invention to be smaller than the valve control means of the prior art. Instead one of the members which defines the variable volume chamber of the hydraulic lash adjuster has a wear surface which is engageable directly with a cam (or with a rocker arm positioned between the cam and the follower member, as seen in one embodiment of WO91/12413). The member has a recess defined on its exterior surface which can be engaged by locking pins. Thus the diameter of the bore of the external cam follower means 151 can be reduced in comparison to the bores of the prior art valve control means since the bore does not have to accomodate a bucket tappet. Instead the cross-sectional area of the bore can be as small as the cross-sectional area of the largest part of the largest of two members which define the expandable chamber of the hydraulic lash adjuster.
- Turning now to figures 6 and 7 a second preferred embodiment of the invention can be seen. The second preferred embodiment is in most respects identical to the first preferred embodiment and like components have been given similar reference numerals with the
prefix 200 being used instead of theprefix 100. - We will only discuss the differences between the second preferred embodiment and the first preferred embodiment.
- In a second preferred embodiment, the second
cam follower member 250 has a slightly different shape, but remains generally cylindrical. Aninner steel skirt 230 is provided in the second embodiment, which is attached to thebody 251 of thecam follower member 250 and which is also attached at its lower end to theouter steel skirt 255. - The locking pins 260, 261 and 262 are of an L-shape in cross-section.
Springs 263 are provided to act between the lower portion of the locking pins and theinner steel skirt 230. Apertures such as 278 are provided in the inner steel skirt to prevent hydraulic locks by allowing the cavities defined around thesprings 263 to be vented to agroove 229 running axially along the exterior of thecam follower member 200. Thelocking pin 260 can be seen to have agroove 228 on the top surface thereof. Thegroove 228 allows fluid to flow from therecess 265 provided on the exterior of thecam follower member 200 to thegroove 229 which allows the fluid to flow to the top surface of the cam follower members. - In figures 8 and 9 a third preferred embodiment of the invention can be seen. The third preferred embodiment is very similar to the second preferred embodiment already described and only differences will be discussed.
- The first important difference between the second and third embodiments is that the third embodiment uses only two locking
pins - The venting of the cavities surrounding the biasing springs 363 is provided for in a different manner in the third embodiment. The locking pins 360 and 361 each have a tapered portion at the front end thereof and a passage running through the locking pins which allows the cavities surrounding the
springs 363 to communicate with therecesses 365 defined on the exterior of thecam follower member 300. The tapered portions of the locking pins 360 and 361 also allow fluid to flow from therecesses 365 through grooves such asgrooves 368 defined on the exterior of thecam follower member 300. The grooves relay the oil to the top surfaces of thecam follower members 300 and 350. - It should be appreciated that in all of the above-noted embodiments, the valve control means are designed to be free to rotate within a bore in a cylinder head, thereby reducing wear by allowing the cams to act on different portions of the surfaces of the cam follower members.
- It will be appreciated that the three preferred embodiments of the invention share the common inventive feature that the inner cam follower member comprises a hydraulic lash adjuster which engages a cam without the need for a bucket tappet. Thus, the inner cam follower means can be reduced in diameter from those of the prior art, with a corresponding reduction in the overall diameter of the valve control means. This is very important to meet packaging constraints within an engine.
- Instead of providing two cams of different profiles, the low lift cam can be replaced by a lobe of circular cross-section such that at low engine speeds the valve can be deactivated (the circular lobe imparting no lift).
- The applicant envisages that the locking pin arrangement when interlocking the inner and outer cam follower members will allow some downward movement of the outer cam follower member from its position in engagement with the base circles of the two cams engaged thereby to a position in which it starts to move the inner cam follower member downwardly. This can be achieved by suitable sizing of the recess in the exterior of the inner member. This feature allows for misalignment created by wear and ensures that the force of the valve spring is transmitted to the base circle portion of the low lift cam (or no lift lobe) at low and high engine speeds. The hydraulic lash adjuster thus adjusts for wear of the most worn component (the low lift cam or no lift lobe) in all conditions. This arrangement ensures that the valve is returned to its valve seat securely at low and high engine speeds, despite differences in wear between the cams of the camshaft (or the no lift lobe and the cam of the camshaft).
Claims (6)
- Valve control means for use in an overhead camshaft internal combustion engine which has a poppet valve (180), cam means comprising a rotatable camshaft (185) having a first portion (181) and a second portion (182) having a different cross-section from the first portion (181), the valve control means comprising:first follower means (100) engageable with the poppet valve (180) and engageable with the first portion (181), which first follower means comprises hydraulic lash adjuster means (101A, 101B,102, 103, 104, 106, 107, 108, 109, 110, 111, 112)having a first member (101A, 101B) which defines a closed bore, a second member (107) movable in the bore of the first member (101A, 101B) and defining with the first member (101A, 101B) a variable volume chamber (108) for hydraulic fluid, conduit means (102, 103, 106) for allowing flow of fluid to the chamber (108) and check valve means (109, 110, 111, 112) for controlling the flow of fluid to the chamber (108),second follower means (150) movable relative to the first follower means (100) and engageable with the second portion (182), said second follower means (150) defining a bore wherein the first follower means (100) is located with at least a portion of the first member (101A,101B) of the hydraulic lash adjuster means being slidable in the bore, andlinking means (160, 163, 167) to enable the first (100) and second (150) follower means to be linked together, wherein in use of the valve control means,when the first (100) and second (150) follower means are not linked the motion of the poppet valve (180) is controlled by the first follower means (100) and the poppet valve (180) is given in each engine cycle the lift of the first portion (181),when the first (100) and second (150) follower means are linked the motion of the poppet valve (180) is controlled by the second follower means (150) and the poppet valve (180) is given in each engine cycle the lift of the second portion (182),characterised in that:the cross section of the bore defined in said second follower means (150) matches in shape and size the cross-section of the portion of the first member (101A, 101B) of the hydraulic lash adjuster means slidable in the bore,the second member (107) of the hydraulic lash adjuster abuts the poppet valve (180), andengagement means (165) is provided on the exterior surface of the first (101A, 101B) member of the hydraulic lash adjuster means (101A, 101B, 102, 103, 104, 105, 106, 107, 108, 110, 111, 112), the engagement means (165) enabling the linking means (160, 163, 167) to link together the first (100) and second (150) follower means.
- Valve control means as claimed in claim 1, wherein the first (100) and second (150) follower means are cylindrical and the first follower means (100) has a diameter in the range 8 to 18mm.
- Valve control means as claimed in any one of the preceding claims, wherein the engagement means comprises a recess (165) in the exterior surface of the first member (101A, 101B) of the hydraulic lash adjuster means and the linking means (160, 163, 167) comprises a locking pin (160) in the second follower means (150) and extendable from the second follower means (150) to engage the recess (165).
- Valve control means as claimed in any one of the preceding claims wherein the first portion (181) of the camshaft (185) is a first cam having a first cam profile, the second portion (182) of the camshaft (185) is a second cam having a second cam profile different to the first cam profile, the first follower means (100) comprises first cam follower means engageable with the first cam and the second follower means (150) comprises second cam follower means engageable with the second cam.
- Valve control means as claimed in any one of claims 1 to 3 wherein the first portion (181) of the camshaft (185) is a portion of circular cross-section which imparts no lift to the valve means (180), the second portion (182) of the camshaft (185) is a cam and the second follower means (150) comprises second cam follower means engageable with the cam.
- An internal combustion engine having valve control means as claimed in any one of the preceding claims wherein a wear surface is provided on an exterior surface of the first member (101A, 101B) of the hydraulic lash adjuster means (101A, 101B, 102, 103, 104, 106, 1007, 109, 110, 111, 112) and the wear surface directly abuts the first portion (181) of the camshaft (185).
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9306221 | 1993-03-25 | ||
GB939306221A GB9306221D0 (en) | 1993-03-25 | 1993-03-25 | Valve control means |
PCT/GB1994/000619 WO1994021899A1 (en) | 1993-03-25 | 1994-03-25 | Valve control means |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0695395A1 EP0695395A1 (en) | 1996-02-07 |
EP0695395B1 true EP0695395B1 (en) | 1997-09-10 |
Family
ID=10732735
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP94910474A Expired - Lifetime EP0695395B1 (en) | 1993-03-25 | 1994-03-25 | Valve control means |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0695395B1 (en) |
JP (1) | JP3321167B2 (en) |
KR (1) | KR100299302B1 (en) |
DE (1) | DE69405555T2 (en) |
ES (1) | ES2107819T3 (en) |
GB (1) | GB9306221D0 (en) |
WO (1) | WO1994021899A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6739293B2 (en) | 2000-12-04 | 2004-05-25 | Sturman Industries, Inc. | Hydraulic valve actuation systems and methods |
US11187119B2 (en) | 2019-09-16 | 2021-11-30 | Eaton Intelligent Power Limited | Latch pin for use in valve lifter and valve lifter |
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DE4314619A1 (en) * | 1993-05-04 | 1994-11-10 | Schaeffler Waelzlager Kg | Pestle |
ES2141350T3 (en) * | 1994-05-03 | 2000-03-16 | Lotus Car | VALVE CONTROL MECHANISM. |
US6076491A (en) * | 1994-05-03 | 2000-06-20 | Lotus Cars Limited | Valve control mechanism |
US5431133A (en) * | 1994-05-31 | 1995-07-11 | General Motors Corporation | Low mass two-step valve lifter |
DE4436952A1 (en) * | 1994-10-15 | 1996-04-18 | Schaeffler Waelzlager Kg | Switchable tappet of a valve train of an internal combustion engine |
DE4440133A1 (en) * | 1994-11-10 | 1996-05-15 | Schaeffler Waelzlager Kg | Switchable cam follower |
DE4440469A1 (en) * | 1994-11-12 | 1996-05-30 | Peter Prof Dr Tenberge | Engageable tappet for valve drive in IC engine |
US5709180A (en) * | 1997-02-06 | 1998-01-20 | General Motors Corporation | Narrow cam two-step lifter |
WO2002029213A1 (en) * | 2000-09-30 | 2002-04-11 | Ina-Schaeffler Kg | Disconnectable support element |
DE10204673A1 (en) * | 2002-02-06 | 2003-08-07 | Ina Schaeffler Kg | Automotive drive switching element comprises diametrically opposed piston pair in groove mountings on inner and outer parts to run nontwistably in grooves. |
DE102006030162A1 (en) * | 2006-06-29 | 2008-01-03 | Schaeffler Kg | Locking device for a switchable valve drive member of a valve train of an internal combustion engine |
DE102007016740A1 (en) * | 2007-04-07 | 2008-10-09 | Schaeffler Kg | Switchable bucket tappets |
DE102007016739A1 (en) * | 2007-04-07 | 2008-10-09 | Schaeffler Kg | Switchable valve drive part |
KR101316459B1 (en) * | 2007-12-07 | 2013-10-08 | 현대자동차주식회사 | Variable tappet for vvl and cda |
KR100962195B1 (en) * | 2007-12-12 | 2010-06-11 | 현대자동차주식회사 | Variable valve lift apparatus |
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US5193496A (en) * | 1991-02-12 | 1993-03-16 | Volkswagen Ag | Variable action arrangement for a lift valve |
EP0608925A1 (en) * | 1993-01-28 | 1994-08-03 | General Motors Corporation | Compact valve-lifters |
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DE1958627A1 (en) * | 1969-11-21 | 1971-06-24 | Daimler Benz Ag | Adjusting device for valve lifts |
US3704696A (en) * | 1971-03-08 | 1972-12-05 | Eaton Corp | Hydraulic valve lifter |
DE3311280A1 (en) * | 1983-03-28 | 1984-10-11 | FEV Forschungsgesellschaft für Energietechnik und Verbrennungsmotoren mbH, 5100 Aachen | Hydraulic valve-clearance compensating element |
DE3347680A1 (en) * | 1983-12-31 | 1984-08-30 | Ernst 8450 Amberg Haubner | Valve timing system for internal combustion engines with two different valve timings |
CA1308977C (en) * | 1986-08-27 | 1992-10-20 | Tsuneo Konno | Valve operating device for internal combustion engine |
US5253621A (en) * | 1992-08-14 | 1993-10-19 | Group Lotus Plc | Valve control means |
CA2075960C (en) * | 1990-02-16 | 1995-09-05 | Clive Dopson | Valve control means |
-
1993
- 1993-03-25 GB GB939306221A patent/GB9306221D0/en active Pending
-
1994
- 1994-03-25 DE DE69405555T patent/DE69405555T2/en not_active Expired - Lifetime
- 1994-03-25 ES ES94910474T patent/ES2107819T3/en not_active Expired - Lifetime
- 1994-03-25 KR KR1019950704068A patent/KR100299302B1/en not_active IP Right Cessation
- 1994-03-25 EP EP94910474A patent/EP0695395B1/en not_active Expired - Lifetime
- 1994-03-25 WO PCT/GB1994/000619 patent/WO1994021899A1/en active IP Right Grant
- 1994-03-25 JP JP52083894A patent/JP3321167B2/en not_active Expired - Lifetime
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US5193496A (en) * | 1991-02-12 | 1993-03-16 | Volkswagen Ag | Variable action arrangement for a lift valve |
EP0608925A1 (en) * | 1993-01-28 | 1994-08-03 | General Motors Corporation | Compact valve-lifters |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6739293B2 (en) | 2000-12-04 | 2004-05-25 | Sturman Industries, Inc. | Hydraulic valve actuation systems and methods |
US11187119B2 (en) | 2019-09-16 | 2021-11-30 | Eaton Intelligent Power Limited | Latch pin for use in valve lifter and valve lifter |
Also Published As
Publication number | Publication date |
---|---|
KR960701282A (en) | 1996-02-24 |
EP0695395A1 (en) | 1996-02-07 |
JP3321167B2 (en) | 2002-09-03 |
DE69405555T2 (en) | 1998-02-19 |
JPH08508077A (en) | 1996-08-27 |
GB9306221D0 (en) | 1993-05-19 |
KR100299302B1 (en) | 2001-11-22 |
ES2107819T3 (en) | 1997-12-01 |
DE69405555D1 (en) | 1997-10-16 |
WO1994021899A1 (en) | 1994-09-29 |
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