Engine valve lifter assembly

Abstract

The present invention provides an engine valve lifter assembly, comprising: a plunger assembly configured to reciprocate in a plunger chamber in response to mechanical pressure from a cam, and comprising a latch compartment, a neck, a retainer, and a spring seat; a lifter body comprising the plunger chamber, a pair of fluid ports, and a pair of latch seats; a latch pin assembly comprising a hydraulically actuated pin; a cap-shaped retainer comprising a rim seated against the plunger chamber, wherein the retainer comprises a hole in a tip; and a plunger spring seated against the rim and extending above the retainer to bias against the spring seat, wherein the neck extends through the hole in the tip, and wherein the retainer is in the retainer.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application date of July 3, 2018, application number 201880044586.8, and invention name “Engine Valve Tappet Assembly”. Technical Field

[0002] The present application provides an engine valve lifter including a reciprocating inner plunger. The engine valve lifter can be configured with a sleeve valve or a latch box for selecting among variable valve actuation technologies. Background Art

[0003] Engine brakes ("EB") have been used for some time as a rocker arm-based solution for compression-release engine braking. Solutions that achieve engine braking via components mounted inside the engine block have not yet been proposed. Instead, complex overhead solutions have been developed. Summary of the Invention

[0004] The apparatus and method disclosed herein overcome the aforementioned shortcomings and improve upon the prior art by providing a modified engine valve lifter including a reciprocating internal plunger. The engine valve lifter can be configured with either a sleeve valve or a latch box, enabling selection between variable valve actuation technologies. The inclusion of a hydraulic lash adjuster allows for additional functionality. Furthermore, the lifter can be configured to be intermediate between a flat tappet and a roller-tappet design.

[0005] An engine valve lifter assembly includes a lifter body, a plunger assembly, and a spring. The lifter body includes an oil control portion, which includes an outer surface, an oil port, and an internal oil chamber, wherein the oil port passes through the lifter body from the outer surface and reaches the oil chamber of the lifter body. The plunger interface end includes an internal plunger chamber and a second spring seat. The selective reciprocating plunger assembly includes a piston end connected to reciprocate in the oil chamber and a cam input end including a spring seat. The spring is biased between the spring seat and the second spring seat. The spring is configured to push the cam input end away from the plunger chamber. A sleeve is connected around the oil control portion of the lifter body, and the sleeve is capable of sliding between a lower position and an upper position to selectively block and unblock the oil port.

[0006] Exemplarily, the oil ports include at least one upper port and at least one lower oil port.

[0007] Exemplarily, the oil control portion further includes an upper groove in fluid communication with the at least one upper port and a lower groove in fluid communication with the at least one lower port, and wherein the sleeve is further configured to selectively block and unblock the upper groove and the lower groove.

[0008] Exemplarily, the tappet body further comprises a cover seat, and wherein the assembly further comprises a cover in the cover seat.

[0009] Exemplarily, the assembly further includes a sleeve spring between the cover and the sleeve, and the sleeve spring is configured to bias the sleeve to the lower position.

[0010] Exemplarily, the assembly further includes an oil receiving step in the outer surface configured to distribute oil below the sleeve and around a portion of the tappet body.

[0011] Illustratively, the assembly further includes a pressurized oil supply device configured to supply pressurized oil to the oil receiving step to lift the sleeve to the upper position.

[0012] Illustratively, the cover includes a hydraulic lash adjuster.

[0013] Exemplarily, the cam input includes a flat portion and the flat portion is configured to act as a flat tappet for following a rotating cam profile.

[0014] Illustratively, the cam input includes a bearing assembly on a bearing shaft, the bearing assembly being configured to follow a rotating cam profile.

[0015] Exemplarily, the plunger chamber further comprises an anti-rotation slot, and wherein the bearing shaft extends into the anti-rotation slot.

[0016] Illustratively, the plunger interface end further includes an edge including a lift limiting side and a lobe following side, wherein the lobe following side is configured to follow a rotating cam profile, and wherein the lift limiting side is configured to act as a travel stop.

[0017] Exemplarily, the cam input end includes a guide cup surrounding the second spring seat, wherein the plunger interface end of the tappet body includes an extension, and wherein the extension is configured to reciprocate in the guide cup.

[0018] Illustratively, the plunger includes an anti-rotation feature for protruding into an anti-rotation groove of the engine block.

[0019] Illustratively, the lifter body includes an anti-rotation feature for protruding into an anti-rotation groove of the engine block.

[0020] An engine valve lifter for a V-type engine includes a plunger assembly, a lifter body, and a locking pin assembly. The plunger assembly is configured to reciprocate in a plunger chamber in response to mechanical pressure from a cam. The plunger assembly includes a latch compartment. The lifter body includes a plunger chamber surrounding the plunger assembly, a pair of fluid ports passing through the lifter body, and a pair of latch seats recessed in the plunger chamber. A latch pin assembly is located in the latch compartment. The latch pin assembly includes a hydraulically actuated pin, a return spring that biases the pins together, and an extension spring that pulls the pins together. The pins are biased to retract from the latch seats in the latch compartment to unlock the plunger assembly from the lifter body, and the plunger assembly is able to slide within the chamber. When hydraulic pressure is applied to the latch pin assembly through a pair of fluid ports, the latch pin extends into the latch seat to lock the plunger assembly to the lifter body.

[0021] Exemplarily, the plunger assembly further comprises a spring groove for accommodating the return spring, and wherein the return spring is in the form of a band.

[0022] Illustratively, the plunger assembly further includes a neck and a spring seat.

[0023] Exemplarily, the push rod further comprises a cap-shaped retainer including a rim seated against the plunger chamber, the retainer including a hole in a tip, and a plunger spring seated against the rim and extending above the retainer to bias against the spring seat of the plunger.

[0024] Illustratively, the neck extends through the aperture in the tip, wherein the neck includes a recess, and wherein the tappet further includes a retainer in the retainer, the retainer seated in the recess.

[0025] Exemplarily, the tappet further includes a hydraulic lash adjuster.

[0026] Illustratively, the plunger assembly includes a cam input configured to have a flat portion that serves as a flat tappet for following a rotating cam profile.

[0027] Illustratively, the plunger assembly includes a cam input including a bearing assembly on a bearing shaft, the bearing assembly being configured to follow a profile of a rotating cam.

[0028] Exemplarily, the pair of latch seats recessed in the plunger cavity include anti-rotation slots in the plunger cavity, and wherein the bearing shaft includes a shaft extension extending into the anti-rotation slots.

[0029] Exemplarily, the tappet further includes an oil receiving step adjacent the pair of fluid ports through the tappet body, the oil receiving step being configured to distribute oil around a portion of the tappet body.

[0030] Illustratively, the tappet body includes an edge including a lift-limiting side and a lobe-following side, wherein the lobe-following side is configured to follow a rotating cam profile, and wherein the lift-limiting side is configured to act as a travel stop.

[0031] Illustratively, the lifter body includes an anti-rotation feature for protruding into an anti-rotation groove of the engine block.

[0032] Illustratively, the tappet body further includes a lubrication port to the pushrod seat.

[0033] Other purposes and advantages will be partially set forth in the following description, and some will be obvious from the description or learned through actual operation. The advantages and purposes will also be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0034] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figures 1A to 1E is a view of an engine valve lifter including the sleeve valve and roller bearing assembly.

[0036] Figure 2 is a view of the plunger including the roller bearing assembly.

[0037] Figure 3A and Figure 3B is a view of the tappet body.

[0038] Figure 4 is a view of an engine valve lifter including a sleeve valve and flat tappet type assembly.

[0039] Figure 5 An illustration of an engine valve lifter including the sleeve valve, flat tappet-type assembly, and hydraulic lash adjuster.

[0040] Figures 6A to 6C is a view of an engine valve lifter including a latch box and roller bearing assembly in a plunger assembly.

[0041] Figure 7 is a view of the plunger including the latch case and roller bearing assembly.

[0042] Figure 8 is a cross section of the latch box.

[0043] Figure 9 is a cross section of the retainer assembly.

[0044] Figure 10A and Figure 10B is a view of an engine valve lifter including the latch box and flat tappet-type assembly.

[0045] Figure 11A and Figure 11B is a view of an engine's valve lifters including the latch box, flat tappet-type assembly, and hydraulic lash adjuster.

[0046] 12A to 12D is an illustration of an engine valve lifter including a sleeve valve, a plunger including a roller bearing assembly and a plunger cup, and a lifter body extension in which the lifter body extension is guided.

[0047] Figure 13 is a view of the plunger including the roller bearing assembly and plunger cup.

[0048] Figure 14 is a view of the tappet body with the extension. DETAILED DESCRIPTION

[0049] Reference will now be made in detail to the illustrated examples in the accompanying drawings. Throughout the drawings, the same reference numerals will be used whenever possible to designate identical or similar components. Directional reference numerals, such as "left" and "right," are provided for ease of reference. Other embodiments will be apparent to those skilled in the art from consideration of the descriptive information and practice of the examples presented herein. For example, the functions of the upper and lower ports can be reversed by appropriately biasing the spring and sleeve and priming the oil supply ports.

[0050] The present invention discloses an engine brake lifter ("EB lifter") for a V-type valvetrain system. By adjusting the height of the lifter body, plunger assembly, and cam lobe profile, other variable valvetrain functions such as dual lift technology, early exhaust valve opening (EEVO), and late exhaust valve closing (LEVC) can be achieved.

[0051] refer to Figures 1A to 1E An engine braking ("EB") solution for a V-type valvetrain system is discussed. An engine valve lifter 101 includes a sleeve valve 50 and a roller bearing assembly 60. Supplemental braking is achieved by incorporating additional functionality into the lifter. The present disclosure enables a vehicle to utilize a supplemental braking system, in this case referred to as compression-release engine braking. Engine braking can help a driver or autonomous vehicle control the vehicle's speed without using the main brakes or service brakes, but it should be noted that EB is not a replacement for the service brakes.

[0052] Lifter 101 includes a lifter body 30, a plunger assembly 70, and a sleeve valve 50, which acts as a one-way valve. Pressurized oil from an oil control valve ("OCV") is used to control the position of sleeve valve 50, thereby activating or deactivating engine braking. Integrating the EB activation and deactivation mechanism with the lifter simplifies the entire EB unit, which also significantly reduces the overall cost of the unit.

[0053] The tappet body 30 is the outer body and housing in which the plunger assembly 70 is placed. Figure 3A and Figure 3B 4. The oil control portion 40 is shown in more detail in FIG. The tappet body 30 includes an outer surface 41, oil ports 43, 45, and an internal oil chamber 47. The oil ports include at least one upper port 43 and at least one lower oil port 45. The number of oil ports is optional, and two upper oil ports 43 and two lower oil ports 45 are shown. The oil ports pass from the outer surface 41 through the tappet body and into the oil chamber 47 of the tappet body. The oil control portion 40 may also include an upper groove 42 in fluid communication with the at least one upper port 43 and a lower groove 44 in fluid communication with the at least one lower port 45. The outer surface 41 may be stepped with a travel step 34 to limit the travel of the sleeve valve 50. Additional external steps, such as an oil receiving step 36, may be included in the outer surface 41. The oil receiving step can be configured to distribute oil below sleeve 53 and around a portion of lifter body 30 to restrict fluid flow when lifter 101 is installed in lifter bore 14 of engine block 10. Additional steps and external surface variations can be included. For example, the circumference of the lifter can be selected to allow a small amount of oil to leak downward to lubricate the movement of lifter 101 in engine block 10 or to lubricate cam 21 on camshaft 20.

[0054] The tappet body 30 also includes a plunger interface end 31 that includes an internal plunger chamber 32 and a second spring seat 38. In this embodiment, the plunger assembly 70 can selectively reciprocate within the tappet body 30. The plunger chamber may include an anti-rotation slot 69. The plunger interface end 31 and the plunger chamber may terminate with an edge 37. The edge 37 may include a lift limiting side 33 and a lobe follower side 35. The lobe follower side 35 is configured to follow the profile of the cam 21 as it rotates on the camshaft 20. The lift limiting side 33 is configured to act as a travel stop that limits the upward sliding of the tappet 101 into the tappet bore 14. The lobe follower side 35 may be configured to follow the main lift lobe (or vertical lift lobe) 22 and return to the base circle 24.

[0055] The sleeve valve 50 is configured to include a sleeve 53 that is slidable along a portion of the outer surface 41. The sleeve 53 is capable of sliding between a lower position and an upper position to selectively block and unblock the oil ports 43 and 45. The sleeve 53 is configured to selectively block and unblock the upper groove 42 and the lower groove 44. The tappet body 30 may include a cap seat 46. The cap 55 may be secured to the cap seat, for example, by a press fit, a compression fit, a snap ring, threads, etc. The cap 55 may be used to bias the sleeve spring 51. In this example, the sleeve spring 51 is interposed between the cap 55 and the sleeve 53 and is configured to bias the sleeve 53 to the lower position.

[0056] The flow of oil into and out of the oil chamber 47 through the oil ports 43, 45 is controlled by the position of the sleeve 53. The position of the sleeve 53 is controlled by the oil pressure from the oil control valve and the hydraulic circuit. The sleeve 53 is coupled around the oil control portion 40 of the tappet body. The sleeve may include an upper lip 52 and a lower lip 54. The sleeve spring 51 may be restrained by the upper lip 52. When the sleeve 53 is biased to the lower position, the lower lip 54 may abut the travel step 34, which serves as a stop. The lower lip 54 may extend a certain distance from the sleeve 53 to limit fluid flow when the tappet 101 is assembled in the tappet bore 14. Then, when the pressurized oil supply device supplies pressurized oil to the oil control port 13 in the tappet bore 14 and the oil chamber 15 in the tappet bore 14, the oil receiving step 36 in the outer surface 41 distributes the oil below the lower lip 54 of the sleeve 53 and around a portion of the tappet body 30. When the oil is pressurized to a predetermined high level, the oil lifts the sleeve 53 to the upper position. When the oil is pressurized to a lower predetermined level, the spring force overcomes the oil pressure and the sleeve returns to the lower position.

[0057] The plunger assembly 70 selectively reciprocates in response to oil pressure supplied to the oil control port 13 and the position of the sleeve 53. In this example, the plunger assembly includes a cam input end 74 and a piston end 71 coupled for reciprocating movement between the oil chamber 47 and the piston seat 48, the cam input end including a spring seat 73. The piston seat 48 may be a bore in the tappet body 30 between the oil chamber 47 and the plunger chamber 32. Figure 2 The plunger assembly 70 is shown separated from the tappet body 30 .

[0058] Neck 72 can connect piston end 71 to cam input end 74. Plunger spring 39 can be seated against spring seat 73, can surround neck 72, and can be biased against second spring seat 38 in plunger chamber 32. Based on design choice, plunger spring 39 is biased between second spring seat 38 and spring seat 73, and plunger spring 39 is configured to urge cam input end 74 away from plunger chamber 32. Thus, piston end 71 can be biased by plunger spring 39 to withdraw from oil chamber 47 and allow pressurized oil to fill oil chamber 47. Piston end 71 seals oil chamber 47 and pushes trapped oil when plunger assembly 70 rises during a lift event, or pushes oil out of oil port 43 during a lost motion event (such as when EB is inactive).

[0059] The cam input includes a plunger body 75, which in this example includes a roller bearing assembly 60. The roller bearing assembly 60 is primarily used to reduce friction losses. The roller bearing assembly 60 includes a roller 61 surrounding an optional bearing 62 on a bearing shaft 63. The bearing shaft 63 can be configured with a shaft extension 64 to extend into an anti-rotation slot 69 within the plunger chamber. Alternatively, an additional anti-rotation pin or other device can be included to prevent the cam input 74 or other aspects of the plunger assembly 70 from rotating relative to the tappet body 30.

[0060] The roller bearing assembly 60 is configured to follow the rotating cam profile of the cam 21. Figures 1A to 1E In the example shown, the bearing is narrow compared to the width of the cam 21. Although the edge 37 of the tappet body 30 is configured to follow the base circle 24 and the primary lift lobe 22, the variable valve lift event is configured as a secondary lift lobe 26. In this example, the secondary lift lobe 26 is a braking event lobe, but it can also be configured for other options such as EEVO and LEVC.

[0061] It is the position of the sleeve 53 of the sleeve valve 50 that controls the flow of oil in and out of the oil chamber 47. The sleeve spring 51 exerts a force on one side of the sleeve 53 due to the preload, and on the other side of the sleeve 53, it is the pressure of the oil that exerts a force on the sleeve 53. The sleeve 53 moves up and down according to these two forces acting on it.

[0062] exist Figure 1A The unactuated state is shown in FIG, and the sleeve 53 is in the lower position. Pressurized oil from, for example, an oil control valve ("OCV") or other components of the hydraulic control circuit is used to control the position of the sleeve valve 50. When the OCV is closed, the oil pressure is low and the sleeve 53 is pushed downward by the preloaded sleeve spring 51. This can be Figure 1B and Figure 1C. The sleeve 53 rests on the travel step 34 and the lower oil port 45, which serves as the oil inlet orifice, is closed. The upper oil port 43 opens. As the secondary lift lobe 26 rotates against the roller 61, the plunger assembly 70 moves upward into the tappet body 30. Since there is no resistance from the sleeve 53, the oil in the oil chamber 47 is pushed out of the upper oil port 43. The plunger spring 39 collapses and the spring force causes the tappet body 30 to not rise with the secondary lift lobe 26. No motion is transmitted to the tappet body. The lift of the plunger assembly 70 is "lost motion". This is Figure 1C Seen in.

[0063] When the OCV is opened, pressurized oil is supplied to push the sleeve 53 upward against the spring force of the sleeve spring 51. This closes the at least one upper oil port 43 that serves as an outlet to the oil chamber 47. This also opens the at least one lower oil port 45 that serves as an inlet orifice to the oil chamber 47. Oil enters the oil chamber 47 and fills the oil chamber 47 through the inlet orifice. This Figure 1D When the secondary lift lobe 26 strikes the roller 61, as shown in FIG. Figure 1E As shown, plunger end 71 moves upward. Due to the incompressibility of oil, oil chamber 47 acts as a rigid body, which in turn pushes tappet body 30. Cap 55 attached to tappet body 30 pushes a pushrod, which is coupled to a rocker arm, which is coupled to a valve, such as an exhaust valve. This action of secondary lift lobe 26 enables engine braking. To implement engine braking, the valve opening is timed immediately after the piston compression stroke in the associated cylinder. Therefore, the energy expended in compressing the charge air is lost to implement engine braking.

[0064] A benefit of the sleeve valve 50 of the tappet 101 is that it does not require a reset function, so there is no need to cycle the cam to return to normal operation after a variable valve lift event.

[0065] Go to Figure 4 and Figure 5 , the plunger assembly 170 of the engine valve lifters 102 and 103 may include a flat portion 177 for forming a flat tappet pattern on the cam input end 174. This shortens the lifter body 130 compared to the previous example, but other aspects of the edge 137, travel step 134, oil receiving step 136, and sleeve valve 150 are the same as above. Figure 4 In the embodiment, the cover 155 is used to bias the sleeve spring 151, but in Figure 5 , a hydraulic lash adjuster ("HLA") 156 includes a cover mounted to cover seat 146. The interface end of HLA 156 is stepped to include a spring step 157. Sleeve spring 151 is biased against spring step 157 on the HLA and against an upper lip of sleeve 153.

[0066] Figures 12A to 14 FIGURE 1 shows an alternative lifter 104 having a lifter body 230 and a plunger assembly 270. The cap 255, sleeve valve 250, and roller bearing assembly 260 are identical to the previous examples. The lifter body 230 is modified so that the plunger interface end 231 includes a necked extension 237. The exterior of the lifter body is stepped to include a travel step 234, an oil receiving step 236, a bore width step 235, and a downward step at the extension 237. The bore width step 235 is sized to guide the lifter body within the lifter bore 14 and to restrict fluid flow between the lifter body 230 and the lifter bore 14.

[0067] The plunger assembly 70 is not completely enclosed by the tappet body 30. Instead, the plunger assembly 270 receives a portion of the extension 237 while the tappet body 230 receives the piston end 271 of the plunger assembly. The cam input end 274 includes a guide cup 276 surrounding a spring seat 273. The plunger spring 239 can be seated against the internal plunger chamber 232. When the spring collapses or expands, the extension 237 is configured to reciprocate in the guide cup 276.

[0068] Earlier alternatives may include anti-rotation features such as a clamp or pin 67 in a groove 66 in the lifter body and a lubrication groove 65 in the lifter body 30. The anti-rotation pin 67 may be raised and lowered in the anti-rotation groove 11 in the lifter bore 14. Figures 12A to 14 In an alternative embodiment, an anti-rotation feature such as a clamp or pin 268 is located in the groove 266 of the plunger body 275 for lifting and lowering in the anti-rotation groove 11 of the tappet bore. A lubrication groove 265 may be included in the plunger body 275.

[0069] The sleeve valve 250 can function the same as the other sleeve valves disclosed herein. However, when the oil control is closed and the oil control port 13 is low pressure, there is no difference on the cam 221 between the tappet body and the plunger assembly. Figures 12A to 14 In the embodiment of FIG, the primary lift lobe 222 is as wide as the rollers 261 of the roller bearing assembly 260. Similarly, the secondary lift lobe 226 is as wide as the rollers 261 of the roller bearing assembly 260. The previous example has a thin secondary lift lobe 26 and a wide primary lift lobe 22. The wide rollers 261 act on the wide secondary lift lobe 226. The position of the lost motion can be moved within the engine block 10.

[0070] Figure 12A A zero input state is shown where the sleeve valve is biased to a lower position. Figure 12B A zero input condition within the engine block 10 is shown. Figure 12CThe plunger assembly 270 is shown in a lifted state, where lost motion is shown due to the secondary lift lobe 226 lifting the plunger assembly 270 when low pressure is supplied to the oil control port 13. Oil can leave the oil chamber 247 through the upper oil port 243. However, in Figure 12D In FIG, engine braking occurs and the exhaust valve is lifted by the amount shown according to the secondary lift lobe profile. Piston end 271 cannot enter oil chamber 247 because upper oil port 243 is blocked when high pressure oil is supplied to lower oil port 245.

[0071] Figure 13 A plunger assembly 270 is shown having a roller bearing assembly 260 in a plunger body 275 having rollers 261, bearings 262 and bearing shafts 263 that function similarly to their counterparts in the previous figures.

[0072] Figure 14 A tappet body 230 is shown having a cap seat 246, an upper groove 242, a lower groove 244, an upper oil port 243, a lower oil port 245, and various steps in the outer surface (including a travel step 234 and an oil receiving step 236), which function similarly to the corresponding components in the above figures.

[0073] In a first aspect, an engine brake device for a V-type engine includes an internal plunger assembly configured to reciprocate in response to oil pressure, spring pressure, and a cam lobe profile. A tappet body surrounds the internal plunger assembly, and the tappet body includes an upper oil port, a lower oil port, and an oil chamber. A portion of the internal plunger is reciprocatable within the oil chamber. A slidable sleeve surrounds the tappet body and is reciprocatable between a position blocking the upper port and a position blocking the lower port. The engine brake device is configured to transmit force from a rotating cam pressing on the internal plunger to a valve stem above the upper port.

[0074] In a second aspect, the apparatus may include a bearing shaft and a bearing on the bearing shaft. The bearing shaft passes through the inner plunger and provides an anti-rotation feature between the inner plunger and the tappet body.

[0075] In a third aspect, an engine brake device for a V-type engine includes an internal plunger configured to reciprocate in response to mechanical pressure. The internal plunger includes a latch compartment. A tappet body surrounds the internal plunger, and the tappet body includes a fluid port passing through the tappet body. A portion of the internal plunger can reciprocate within the chamber. A latch pin assembly 580 is located in the latch compartment. The latch pin assembly includes a hydraulically actuated pin 581 configured to reciprocate in the latch compartment, a return spring 582 that biases the pins together, and an extension spring 583 that biases the pins apart. The pin is biased to extend from the latch compartment, thereby locking the internal plunger and the tappet body together. However, when hydraulic pressure is applied to the latch pin assembly through the fluid port, the pins move together to unlock the latch pin from the tappet body and allow the portion of the internal plunger to reciprocate within the chamber. The third aspect consists of Figures 6A to 11B The push rods 105, 106, and 107 are used to realize this.

[0076] Alternatively, an engine valve lifter 105, 106, 107 for a V-type engine may include a plunger assembly 370, 470, a lifter body 330, 430, and a latch pin assembly 580. Figure 6A and Figure 6B , the plunger assembly 370 is configured to reciprocate in the plunger chamber 332 in response to mechanical pressure from the cam 321. The plunger assembly 370 includes a latch compartment 379 having a latch oil port 390 leading thereto through the plunger body 375. An oil receiving step 391 may be included in the plunger body 375 to direct oil to the latch oil port 390 and distribute the oil around the plunger body 375.

[0077] The plunger assembly can also include a neck 372 having a notch 378 at a first end and a spring seat 373 at an end closest to the plunger body 375. The plunger assembly 370 can be connected to a cap-shaped retainer 385 that includes a rim 384 that rests against the upper limit 338 of the plunger chamber 332. The rim 384 can serve as a locator and spring seat to position the plunger spring 339 relative to the plunger chamber 332. The retainer 385 can include a webbing portion 382 that forms a tubular spring guide, and the crown can include a hole 383 in the tip of the crown. The plunger spring 339 can rest against the rim 384, and the plunger spring 339 can extend the webbing portion 382 above the retainer to bias it against the spring seat 373 of the plunger assembly 370. The neck 372 of the plunger assembly extends through a hole 383 in the tip, and the retainer can serve as a guide for the plunger assembly as it is raised and lowered in the plunger chamber 332. The neck 372 can include a notch 378, and a retainer 380 seated in the notch can secure the plunger notch 378 in the retainer. An optional gasket or seal 381 can also be seated in the retainer 385.

[0078] The tappet body 330 is a housing in which the plunger assembly 370 is placed. The tappet body 330 includes a plunger chamber 332 surrounding the plunger assembly 370. An upper limit 338 is formed in the chamber. A spring guide in the form of a cap-shaped retainer 385 is positioned against the upper limit 338. A plunger spring 339 is positioned around the retainer 385 to bias the plunger assembly 370 and the tappet body apart. The plunger chamber 332 also includes a pair of latch seats 396 recessed into the plunger chamber wall. The pair of latch seats 396 may include anti-rotation slots in the plunger chamber. A pair of fluid ports 392 pass through the tappet body 330. The oil control port 16 in the engine block can supply pressurized fluid to the pair of fluid ports 392 via an oil receiving step 336 adjacent to the pair of fluid ports passing through the tappet body. The oil receiving step 336 is configured to distribute oil around a portion of the tappet body.

[0079] A latch pin assembly 580 is mounted in the latch compartment 379. The latch pin assembly 580 includes a hydraulically actuated pin 581, a return spring 582 that biases the pins 581 together, and an extension spring 583 that pulls the pins 581 together. The plunger assembly 370 may also include a spring recess 377 to accommodate the return spring 582. The return spring 582 may be in the form of a band. The pin 581 may be biased to retract from the latch seat 396 in the latch compartment 379 to unlock the plunger assembly 370 from the tappet body 330, thereby enabling the plunger assembly to slide within the chamber. When the latch compartment 379 is free of pressurized fluid, the latch pins 581 are pulled toward each other by the extension spring 583, and the plunger assembly 370 disengages from the tappet body 330. When the chamber 584 is filled with pressurized oil, the pins 581 move away from each other against the spring load, and the plunger assembly 370 engages the tappet body 330. When hydraulic pressure is applied to the latch pin assembly 580 through the oil control port 16 , through the pair of fluid ports 392 , and through the latch oil port 390 , the latch pin 581 extends into the latch seat 396 to lock the plunger assembly 370 to the tappet body 330 .

[0080] exist Figures 6A to 11B In FIG. 5 , piston assemblies 370 and 470 engage an oil-controlled latch pin assembly 580. This provides an engine braking solution or dual lift capability for a V-valve train system. Pressurized oil from a hydraulic control circuit, such as one that includes an oil control valve (OCV), is used to engage or disengage the latch pin assembly 580, thereby activating or deactivating a variable valve lift function, such as engine braking.

[0081] Figures 6A to 11BThe tappet body 330 in FIG. 1 also includes a lubrication port 356, 456 that leads to a pushrod seat 359, 459. The oil control port 17 can supply oil to the lubrication port 356, 456. Sometimes, lubricant can flow down the pushrod and lubricate the pushrod, such as with a cap 55 or HLA 56, 456 design.

[0082] Additional lifter body 330, 430 features may include anti-rotation features, such as pin 367 for protruding into anti-rotation groove 11 of the engine block. The lifter body may also include edges 337, 437 that include a lift-limiting side 333, 433 and a lobe-following side 335, 435. The lobe-following side is configured to follow the rotating cam profile, while the lift-limiting side is configured to act as a travel stop.

[0083] In this case, the camshaft 320, 420 includes a cam 321, 421 having two lobes: a primary lift lobe 322, 422 and a secondary lift lobe 326, 426. The primary lift lobe 322, 422 extends entirely along the width of the cam 321, 421, while the secondary lift lobe 326, 426 is located in the middle of the cam 321, 421, with a width slightly smaller than the width of the flat 477 or roller 361 used. By way of example, pressurized oil from the OCV is used to control the position of the latch pin 581. When the OCV is closed, the oil pressure is low and the pin 581 is pulled toward each other. In this case, the plunger assembly 370, 470 and the tappet body 330, 430 are disengaged and move independently of each other. During the disengaged state, when the secondary lift lobes 326, 426 of the cams 321, 421 strike the plunger assemblies 370, 470, the plunger assemblies 370, 470 individually move upward to compress the plunger springs 339, 439, thereby not imparting lift to the tappet bodies 330, 430. Figure 6B As shown, lost motion occurs. In this case, the engine brake is closed. The valve is raised and lowered by the main lift cam 322, 422 through the push rod, rocker arm, etc.

[0084] When the OCV is open, pressurized oil pushes latch pins 581 away from each other and lifter body 330 engages plunger assembly 370. During the engaged state, when secondary lift lobe 326, 426 strikes roller 361 or flat 477 of plunger assembly 370, 470, the entire lifter assembly moves upward, which in turn opens the associated exhaust valve for a brief period of time. Engine braking is active and the exemplary lift is Figure 6C For engine braking, the exhaust valve opening is timed immediately after the compression stroke of the piston in the combustion cylinder. Therefore, the energy expended in compressing the charge air is lost to the atmosphere to perform engine braking. Adjusting the timing of the secondary lift lobe allows for other variable valve technologies.

[0085] Figures 6A to 7 The plunger assembly 370 includes a roller bearing assembly 360 on the cam input end of the plunger body 375. The roller bearing assembly functions similarly to the previous embodiment via rollers 361, optional bearings 362, and bearing shafts 363. The roller bearing assembly 360 is configured to follow the profile of a rotating cam. Alternatively, the pair of latch seats 396 recessed in the plunger chamber 332 may include anti-rotation slots 369 in the plunger chamber. The bearing shaft 363 may include a shaft extension 364 that extends into the anti-rotation slots 369.

[0086] Figures 10A to 11B An alternative embodiment uses flats 477 to form a flat tappet pattern on the cam input end of plunger assembly 470. Plunger assembly 470 has many similarities to plunger assembly 370, such as latch compartment 479, latch oil port 490, oil receiving step 491, spring seat 473, neck 472, notch 478, and retainer 480.

[0087] like Figure 11A and Figure 11B As shown, HLA 456 can be integral with lifter body 430. HLA 456 can be press-fit or otherwise attached to lifter body 430.

[0088] Additional design considerations may include the disclosed design not requiring a reset function. There is also room for design options that do not increase lift. Another design alternative includes the possibility of lift loss during the exhaust stroke due to the collapse of the plunger assembly on the main lift lobes 22, 222, 122, 322, 422 when the EB is closed. For this reason, the lift profile of the main lift lobes can be greater than the actual expected valve lift. The profile of cam 21 can be designed for higher lift. Therefore, when the EB is open, the exhaust valve lift during the exhaust stroke can be greater than the actual expected valve lift. The piston crown can then be modified to avoid valve impact on the piston. In addition, the disclosed alternative enables the implementation of technologies including EEVO and LEVC. This alternative design is compatible with a reset function when the customer does not want increased lift. This alternative design is compatible with intervening cycle technology to reduce the exhaust curve from increased lift engine braking to a normal lift exhaust curve.

Claims

1. An engine valve lifter assembly for a V-type engine, comprising: A plunger assembly configured to reciprocate in a plunger chamber in response to mechanical pressure from a cam, the plunger assembly comprising: Latch compartment; and a bearing assembly on a bearing shaft, wherein the bearing shaft includes a shaft extension; A tappet body, the tappet body comprising: the plunger chamber, the plunger chamber surrounding the plunger assembly; a pair of fluid ports extending through the tappet body; a pair of latch seats recessed into the plunger chamber; and anti-rotation slots in the plunger chamber; and a latch pin assembly in the latch compartment, the latch pin assembly including a hydraulically actuated pin, wherein the shaft extension extends into the anti-rotation slot, wherein the hydraulically actuated pin is configured to retract from the pair of latch seats to unlock the plunger assembly from the tappet body so that the plunger assembly is configured to slide within the chamber, and When hydraulic pressure is applied to the latch pin assembly through the pair of fluid ports, the hydraulically actuated pin is configured to extend into the pair of latch seats to lock the plunger assembly to the tappet body. 2 . The engine valve lifter assembly of claim 1 , further comprising an oil receiving step adjacent the pair of fluid ports, wherein the oil receiving step is configured to distribute oil around a portion of the lifter body.

3. The engine valve lifter assembly of claim 1 , wherein the lifter body further comprises an edge, the edge comprising a lift-limiting side and a lobe-following side, wherein the lobe-following side is configured to follow a rotating cam profile, and wherein the lift-limiting side is configured to act as a travel stop. 4 . The engine valve lifter assembly of claim 1 , wherein a portion of the lifter body is configured to protrude into an anti-rotation groove of an engine block.

5. The engine valve lifter assembly of claim 1, wherein the lifter body further comprises a lubrication port to a pushrod seat.

6. The engine valve lifter assembly of claim 1, wherein the plunger assembly further comprises a spring groove and a return spring disposed in the spring groove, and wherein the return spring comprises a band surrounding a portion of the hydraulically actuated pin.

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