CN110645066B - Compression release type engine in-cylinder braking device - Google Patents
Compression release type engine in-cylinder braking device Download PDFInfo
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- CN110645066B CN110645066B CN201911081759.6A CN201911081759A CN110645066B CN 110645066 B CN110645066 B CN 110645066B CN 201911081759 A CN201911081759 A CN 201911081759A CN 110645066 B CN110645066 B CN 110645066B
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- 230000006835 compression Effects 0.000 title claims abstract description 23
- 238000007906 compression Methods 0.000 title claims abstract description 23
- 230000007246 mechanism Effects 0.000 claims abstract description 39
- 239000003921 oil Substances 0.000 claims description 275
- 239000010705 motor oil Substances 0.000 claims description 23
- 230000001105 regulatory effect Effects 0.000 claims description 17
- 239000000346 nonvolatile oil Substances 0.000 claims description 14
- 230000002093 peripheral effect Effects 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims description 4
- 230000004044 response Effects 0.000 abstract description 5
- 238000009434 installation Methods 0.000 description 7
- 230000009471 action Effects 0.000 description 5
- 239000010720 hydraulic oil Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- XEBWQGVWTUSTLN-UHFFFAOYSA-M phenylmercury acetate Chemical compound CC(=O)O[Hg]C1=CC=CC=C1 XEBWQGVWTUSTLN-UHFFFAOYSA-M 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
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
- F01L13/06—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking
- F01L13/065—Compression release engine retarders of the "Jacobs Manufacturing" type
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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
- F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
- F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
- F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
- F02D13/04—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation using engine as brake
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Valve Device For Special Equipments (AREA)
Abstract
The invention discloses a compression release type engine in-cylinder braking device, which comprises: the camshaft is provided with a plurality of exhaust cams; the camshaft has seted up the logical oil pocket along the axial, and logical oil pocket is only through a set of rotatory oil feed interface arrangement and a set of oil supply unit intercommunication, and the mounting hole has been seted up along radial to the exhaust cam, is provided with sliding plunger mechanism in the mounting hole, is provided with throttling arrangement in the logical oil pocket. The invention not only improves the working reliability of the engine, but also improves the oil filling speed of the oil supply device to the oil through cavity of the cam shaft after the engine enters the in-cylinder braking state, so that all sliding plungers are protruded faster to form braking bulges, the response time of in-cylinder braking is reduced, the structure is simple and compact, and the cost is low.
Description
Technical Field
The invention relates to the technical field of in-cylinder braking of engines, in particular to a compression release type in-cylinder braking device of an engine.
Background
The in-cylinder braking technology of the engine mainly goes through the development processes of exhaust butterfly valve braking, air leakage braking, compression release braking and the like, wherein the compression release braking technology is the technology with the best engine braking performance at present, and the basic principle is as follows: when the engine is towed backward, the piston compresses gas in the cylinder in the process of ascending the compression stroke piston, and braking power is generated. Before compression top dead center, the compression release type braking device drives the exhaust valve to open a certain opening degree, the compressed high-temperature high-pressure charge in the cylinder is discharged, at the moment, the pressure in the cylinder is rapidly reduced, after a certain crank angle is passed, the exhaust valve is closed again, the piston moves downwards, the work of the charge in the cylinder on the piston is greatly reduced because the charge in the cylinder is greatly reduced, and the reverse braking power of the charge in the cylinder on the piston is reduced or eliminated.
Chinese patent CN201241740Y discloses an integrated brake device for rocker arm of four-stroke internal combustion engine, which is provided with two brake protrusions on the control cam for increasing intake air amount by opening the intake valve before the end of intake stroke and releasing pressure by opening the exhaust valve before the end of compression stroke to realize in-cylinder braking of the engine, and a hydraulic control lash compensation mechanism is required to be provided on the rocker arm in order to cancel valve lift caused by the brake protrusions during normal operation of the engine. Because the normal running state occupies most of the running state of the whole engine, the clearance compensation mechanism is in a working state in most of the running time of the engine, and has higher requirements on reliability and the like, and the structure is more complex.
In order to solve the above technical problems and improve the reliability of the corresponding parts of the engine, chinese patent application CN201911000047.7 proposes a compression release type in-cylinder brake device for the engine, which has a through oil cavity formed on a cam shaft of a valve train and a mounting hole formed on an exhaust cam, wherein the through oil cavity is communicated with an oil supply device through a rotary oil inlet interface device, and a sliding plunger mechanism is arranged in the mounting hole; when the electromagnetic reversing valve of the oil supply device is powered off, the oil through cavity is communicated with the oil pan through the pressure relief oil circuit and is communicated with the engine oil circuit through the pressure relief oil circuit; when the electromagnetic reversing valve is electrified, the engine oil path supplies oil to the oil through a one-way oil path, and the sliding plunger mechanism stretches out of the cam surface of the exhaust cam to form a braking bulge when the sliding plunger mechanism is not blocked by the tappet.
However, it was found during the test that for a six-cylinder or more multi-cylinder engine, since the cylinders of the engine are operated sequentially, those sliding plungers that are not blocked by the lifter or valve cover would extend to form a brake lobe after the engine enters an in-cylinder braking state, while those sliding plungers that are blocked by the lifter or valve cover would not extend to form a brake lobe. Under the condition that the oil passing cavity is not fully filled with oil, the blocked sliding plungers extend out under the action of oil pressure of engine oil once rotating along with the camshaft and passing over the tappet or the valve protective cap, so that a certain oil containing space is formed in the mounting hole, at the moment, or slightly after a little time, when the sliding plungers which extend out to form the braking protrusions are again pressed by the tappet or the valve protective cap, the oil in the oil passing cavity is back pressed, the pressure is far greater than the pressure of the engine oil, the part of the back pressing oil cannot return to an engine oil way through a one-way oil way, but can flow back into the oil containing space formed by extending out of the sliding plungers, so that the phenomenon that the sliding plungers are prone to act is generated in a certain time, the oil filling process of the oil feeding device for the oil passing cavity is very slow, only when all the sliding plungers extend out of the mounting hole to form braking protrusions, the phenomenon can be stopped after the oil passing cavity is fully filled with the oil, and the sliding plungers can really act as braking protrusions.
In order to increase the oil filling speed of the oil supply device to the oil passing cavity after the engine enters the in-cylinder braking state, so that all sliding plungers are protruded faster to form braking protrusions, and the response time of in-cylinder braking is shortened, another embodiment is provided in the Chinese patent application CN201911000047.7, which is provided with a plug in the oil passing cavity, the plug divides the oil passing cavity into two parts, two ends of the oil passing cavity are respectively provided with a rotary oil inlet interface device, and the rotary oil inlet interface devices are respectively communicated with one oil supply device to supply oil. Because the two oil supply devices can supply oil respectively, the oil supply time of the two oil passing cavities can be staggered, the device is suitable for the actual working condition of sequential work of each cylinder of the engine, six sliding plungers corresponding to one oil passing cavity are changed into three sliding plungers corresponding to each oil passing cavity, and in the same period, the time that all the tappet contacts with a cam base circle is longer at the same time, so that the sliding plungers can be protruded faster to form braking bulges after entering a braking state in the cylinder. However, this structure requires two sets of oil supply devices, occupies more engine space, and is costly.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides the compression release type engine in-cylinder braking device to improve the working reliability of an engine.
In order to solve the technical problems, the invention provides a compression release type engine in-cylinder braking device, comprising: the valve mechanism comprises a cam shaft, wherein the cam shaft is provided with a plurality of exhaust cams; the camshaft is provided with a through oil cavity along the axial direction, the camshaft is provided with a rotary oil inlet interface device, the through oil cavity is communicated with a set of oil supply device only through a set of rotary oil inlet interface device, the exhaust cam is provided with a mounting hole along the radial direction, the mounting hole is communicated with the through oil cavity, and a sliding plunger mechanism is arranged in the mounting hole; the oil supply device comprises an electromagnetic reversing valve, a pressure relief oil circuit and a one-way oil circuit, wherein when the electromagnetic reversing valve is powered off, the oil through cavity is communicated with the oil pan through the pressure relief oil circuit and is communicated with an engine oil circuit through the pressure relief oil circuit; when the electromagnetic reversing valve is electrified, the engine oil circuit supplies oil to the oil through the one-way oil circuit, and the sliding plunger mechanism stretches out of the cam surface of the exhaust cam to form a braking bulge when the sliding plunger mechanism is not blocked by a tappet or a valve protecting cap of the valve mechanism; and a throttling device is arranged in the oil passing cavity.
The throttling device comprises a device body arranged in the oil through cavity, a throttling channel is formed in the device body, the throttling channel is provided with a first opening end close to the rotary oil inlet interface device and a second opening end far away from the rotary oil inlet interface device, the throttling channel is provided with a conical surface, a valve ball is arranged in the throttling channel and is matched with the conical surface, a throttling pressure relief spring is arranged in the throttling channel between the valve ball and the first opening end, and a valve ball limiting structure is arranged in the throttling channel between the valve ball and the second opening end; preferably, the valve ball is provided with an orifice communicating the first opening end and the second opening end.
The throttling device comprises a device body arranged in the oil through cavity, and the device body is provided with a throttling hole.
The sliding plunger mechanism comprises a sliding plunger, a plunger return spring, a pin shaft and a plug, wherein the installation hole is a stepped hole, the stepped hole comprises a large hole and a small hole, the small hole penetrates through a cam shaft part on one side of the oil passing cavity in the radial direction and forms a blind hole on the cam shaft part on the other side of the oil passing cavity, the large hole is recessed from the oil passing cavity to the opening direction of the small hole, the pin shaft is installed in the large hole, the sliding plunger is installed in the small hole, a spring installation hole is axially formed in the sliding plunger, a long slot hole is radially formed in the sliding plunger, the pin shaft is slidably arranged in the long slot hole, the plunger return spring is clamped in the spring installation hole by the pin shaft, when the oil passing cavity is in a pressure relief state, the plunger return spring props the sliding plunger against the bottom of the blind hole, and the plug is screwed on the outer opening end of the spring installation hole and seals the spring installation hole.
The rotary oil inlet interface device is arranged at the opening end part of the oil passing cavity.
The rotary oil inlet interface device comprises a fixed oil sleeve, the camshaft is provided with an oil inlet journal, the oil inlet journal is rotatably and hermetically arranged on the fixed oil sleeve, an annular oil groove is formed in the outer peripheral surface of the oil inlet journal, the annular oil groove is communicated with the oil through cavity, an oil through hole is formed in the fixed oil sleeve, the oil through hole is communicated with the annular oil groove, an end cover for sealing an opening of the oil through cavity is arranged at the end part of the camshaft, and an annular flange for limiting the axial movement of the fixed oil sleeve is arranged on the end cover.
Wherein, the electromagnetic reversing valve is a two-position three-way electromagnetic reversing valve.
The one-way oil way is internally provided with a one-way valve, the pressure reducing oil way is internally provided with a pressure reducing valve, and the pressure reducing oil way is internally provided with an overflow pressure maintaining valve.
The structure of the overflow pressure maintaining valve is the same as that of the pressure reducing valve.
The pressure reducing valve comprises a valve body, a valve cavity is formed in the valve body, an oil inlet, an oil outlet and a pressure regulating port are formed in the valve cavity, a valve ball and a pressure regulating spring are arranged in the valve cavity, a pressure regulating screw is screwed on the pressure regulating port, and the valve ball is elastically pressed against the oil inlet.
After the technical scheme is adopted, the invention has the technical effects that:
1) When the engine is in a normal working mode, the electromagnetic directional valve is powered off, the oil passing cavity is communicated with the oil pan through the pressure relief oil way and is communicated with an engine oil way through the pressure relief oil way, and at the moment, the oil pressure in the oil passing cavity is insufficient to push the sliding plunger mechanism to act; when the engine enters the in-cylinder braking mode, the electromagnetic directional valve is electrified, the engine oil way supplies oil to the oil through the one-way oil way, the sliding plunger mechanism stretches out of the cam surface of the exhaust cam to form a braking bulge when the sliding plunger mechanism is not blocked by a tappet or a valve protection cap of the valve actuating mechanism, and the braking bulge pushes the valve tappet or the valve protection cap to open an exhaust valve, so that in-cylinder braking is completed. Compared with the prior art, when the engine is in the in-cylinder braking mode, the sliding plunger extends out of the cam surface of the exhaust cam, the working time of the sliding plunger mechanism is very short, when the engine is in the normal working state, the sliding plunger is recovered in the mounting hole of the exhaust cam, the whole exhaust cam is like a common exhaust cam, the working reliability of the engine is higher, and the oil supply device can push the sliding plunger mechanism to act only by means of the pressure of an engine oil way without adopting a pressurizing mechanism, so that the structure is simpler. The invention is suitable for the engine with the lower arranged cam shaft and also suitable for the engine with the overhead arranged cam shaft.
2) In the invention, because the throttle device is arranged in the oil passing cavity, the oil in the left cavity can not be pressed back to the right cavity or can be pressed back to a small part through the throttle hole, so that the phenomenon of 'this point' of the sliding plunger is greatly reduced, the oil filling speed of the oil passing cavity is accelerated, and the response time of braking in a cylinder is shortened.
3) In the invention, the effects of two sets of oil feeding devices and two sets of rotary oil feeding interface devices can be achieved by only one set of oil feeding device and one set of rotary oil feeding interface device, the structure is more compact, and the cost is lower.
Drawings
FIG. 1 is a schematic view showing the construction of an embodiment 1 of a compression-release type in-cylinder brake apparatus for an engine according to the present invention;
fig. 2 is a hydraulic schematic diagram of the oil supply apparatus of fig. 1;
FIG. 3 is an enlarged view of a portion of the portion I of FIG. 1;
FIG. 4 is a reference view showing an operation state when the sliding plunger is extended in embodiment 1 shown in FIG. 1;
FIG. 5 is a cross-sectional view at A-A in FIG. 1;
FIG. 6 is a schematic illustration of the camshaft portion of FIG. 3 with the sliding plunger mechanism removed;
FIG. 7 is a cross-sectional view of the configuration of the pressure relief valve of FIG. 2;
FIG. 8 is a reference view showing an operation state of the sliding plunger mechanism in a position opposed to the tappet in the normal operation of the engine in embodiment 1;
FIG. 9 is a reference view showing an operating state of the sliding plunger mechanism at a position deviated from a tappet position in the normal operation of the engine in embodiment 1;
FIG. 10 is a reference view showing an operation state of the sliding plunger mechanism at a position opposed to the lifter immediately after the engine enters the in-cylinder braking mode in embodiment 1;
FIG. 11 is a reference view showing an operating state of the sliding plunger mechanism at a position deviated from a lifter position when the engine is in an in-cylinder braking mode in embodiment 1;
FIG. 12 is a reference view showing an operation state of the engine of embodiment 1 when the sliding plunger mechanism is extended and returned to a position opposite to the lifter in the in-cylinder braking mode;
fig. 13 is a schematic structural view of the working principle of embodiment 1;
fig. 14 is a schematic structural view of the working principle of embodiment 2;
fig. 15 is a schematic structural diagram of the working principle of embodiment 3;
FIG. 16 is a longitudinal cross-sectional enlarged view of the throttle device in embodiment 1;
FIG. 17 is a longitudinal cross-sectional enlarged view of the throttle device in embodiment 2;
FIG. 18 is a longitudinal cross-sectional enlarged view of the throttle device in embodiment 3;
in the figure: 10-exhaust valve, 11-valve spring, 12-valve rocker, 13-rocker arm shaft, 14-pushrod, 15-tappet, 20-camshaft, 21-intake cam, 22-exhaust cam, 23-oil passing cavity, 24-annular oil groove, 25-timing gear, 26-throttle device, 26a 1-limit pin, 26a 2-valve ball, 26a 3-device body, 26a 4-throttle relief spring, 26 b-throttle device, 26b 1-throttle orifice, 26 c-throttle device, 26c 1-limit pin, 26c 2-valve ball, 26c 3-device body, 26c 4-throttle relief spring, 26c 5-throttle hole, 30-rotary oil inlet interface device, 31-end cover, 32-fixed oil sleeve, 321-oil through hole, 40-pressure reducing valve, 41-valve body, 42-valve ball, 43-pressure regulating spring, 44-pressure regulating screw, P1-oil inlet, P2-oil outlet, 50-overflow pressure maintaining valve, 60-oil pan, 70-sliding plunger mechanism, 71-sliding plunger, 711-spring mounting hole, 712-long slot hole, 72-plunger return spring, 73-pin shaft, 74-plug, 80-electromagnetic reversing valve, phi x-large hole, phi y-small hole and 100-one-way valve.
Detailed Description
The invention will be further described with reference to the drawings and examples.
Example 1
In this embodiment, as shown in fig. 1, for example, a six-cylinder four-stroke engine is taken as an example, a compression release type engine in-cylinder braking device, a valve rocker 12 is rotatably installed on a rocker arm shaft 13, a push rod 14 and an exhaust valve 10 are separately arranged on two sides of the rocker arm shaft 13, and when a tappet 15 and the push rod 14 push the valve rocker 12 from one side to swing around the rocker arm shaft 13 under the action of an exhaust cam 22 of a camshaft 20, the other side of the valve rocker 12 presses the exhaust valve 10 to open the valve; when the camshaft rotates by a prescribed angle, the exhaust valve 10 returns under the action of the valve spring 11, and the valve is closed. The camshaft 20 is kept synchronized with the engine crankshaft by a timing gear 25.
The above structure is a part of the engine valve mechanism for controlling the action of the exhaust valve, and the camshaft 20 is further provided with a plurality of intake cams 21 for controlling the opening and closing of the corresponding intake valves, which will not be described herein.
As shown in fig. 1, the camshaft 20 is provided with a through oil cavity 23 along the axial direction, the camshaft 20 is provided with a rotary oil inlet interface device 30, the through oil cavity 23 is communicated with an oil supply device through the rotary oil inlet interface device 30, the exhaust cam 22 is provided with a mounting hole along the radial direction, the mounting hole is communicated with the through oil cavity 23, a sliding plunger mechanism 70 is arranged in the mounting hole, a throttling device 26 is arranged in the through oil cavity 23, and the throttling device 26 has various structures, which will be described in detail below in connection with different embodiments.
As shown in fig. 2, the oil supply device has only one set, and comprises an electromagnetic directional valve 80, a pressure relief oil path and a one-way oil path, wherein when the electromagnetic directional valve 80 is powered off, the oil passing cavity 23 is communicated with the oil pan 60 through the pressure relief oil path and is communicated with an engine oil path through the pressure relief oil path; when the electromagnetic directional valve 80 is electrified, the engine oil path supplies oil to the oil passing cavity 23 through the one-way oil path, and the sliding plunger mechanism 70 extends out of the cam surface of the exhaust cam 22 to form a braking protrusion when not blocked by the tappet 15 or the valve protecting cap of the valve mechanism.
Preferably, the electromagnetic directional valve 80 is a two-position three-way electromagnetic directional valve, the relief oil path is provided with an overflow pressure maintaining valve 50, the unidirectional oil path is provided with a unidirectional valve 100, and the relief oil path is provided with a relief valve 40.
The pressure reducing valve 40 may adopt a structure of a common pressure reducing valve, and based on cost consideration, a new structure may also be adopted, as shown in fig. 7, the valve body 41 is provided with a valve cavity, the valve cavity is provided with an oil inlet P1, an oil outlet P2 and a pressure regulating port, a valve ball 42 and a pressure regulating spring 43 are installed in the valve cavity, the pressure regulating port is screwed with a pressure regulating screw 44, and the valve ball 42 is elastically pressed against the oil inlet. The operating principle of the pressure reducing valve 40 is as follows:
Setting: the elasticity of the pressure regulating spring 43 is F;
the oil pressure of the oil inlet P1 is N1 to the pressure of the valve ball 42;
The oil pressure of the oil outlet P2 is N2 to the pressure of the valve ball 42;
The force with which the sealing valve ball opens is then: f+n2=n1, N2< N1;
The size of the pressure regulating spring 43 is adjusted through the pressure regulating screw 44, so that the size of N2 can be changed, namely the oil pressure of the oil outlet P2 is changed.
The relief pressure maintaining valve 50 may be a conventional relief valve or a relief valve 40.
As shown in fig. 3,4, 5 and 6, the sliding plunger mechanism 70 includes a sliding plunger 71, a plunger return spring 72, a pin 73 and a plug 74, the mounting hole is a stepped hole, the stepped hole includes a large hole Φx and a small hole Φy, the small hole Φy radially penetrates through a cam shaft portion on one side of the oil passing cavity 23 and forms a blind hole on a cam shaft portion on the other side of the oil passing cavity 23, the large hole Φx is recessed from the oil passing cavity 23 toward an opening direction of the small hole Φy, the pin 73 is mounted in the large hole Φx, the sliding plunger 71 is mounted in the small hole Φy, a spring mounting hole 711 is axially provided in the sliding plunger 71 and a long slot 712 is radially provided, the pin 73 is slidably disposed in the long slot 712, the plunger return spring 72 is clamped in the spring mounting hole 711 by the pin 73, when the oil passing cavity 23 is in a pressure releasing state, the plunger return spring 72 abuts the sliding plunger 71 against a bottom of the blind hole, and the plug 711 is screwed to an outer opening end of the spring mounting hole 711 and seals the spring mounting hole 711.
During assembly, the sliding plunger 71 is firstly installed in the small hole phiy, the plunger return spring 72 is installed in the spring installation hole 711, the plunger return spring 72 is compressed, the pin shaft 73 is installed in place from the oil through cavity 23, then the plunger return spring 72 is loosened, the pin shaft 73 is clamped in the large hole phix, and finally the plug 74 is screwed to seal the spring installation hole 711.
As shown in fig. 1, the rotary oil inlet interface device 30 is disposed at one open end of the oil through cavity 23, the rotary oil inlet interface device 30 includes a fixed oil jacket 32 and an end cover 31, the camshaft 20 is provided with an oil inlet journal, the oil inlet journal is rotatably and sealingly mounted on the fixed oil jacket 32, an annular oil groove 24 is disposed on the outer peripheral surface of the oil inlet journal, the annular oil groove 24 is communicated with the oil through cavity 23, the fixed oil jacket 32 is disposed with an oil through hole 321, and the oil through hole 321 is communicated with the annular oil groove 24. The end cover 31 is arranged at the end of the camshaft 20 and is used for sealing the opening of the oil through cavity 23, and the end cover 31 is also provided with an annular flange used for limiting the axial movement of the fixed oil sleeve 32.
In the present invention, the annular oil groove 24 may be formed in the inner peripheral surface of the fixed oil jacket 32 instead of the outer peripheral surface of the oil inlet journal. The annular oil groove 24 may communicate hydraulic oil from a high-pressure oil passage with the oil passage chamber 23 when the camshaft 20 rotates.
Under the condition that a throttling device is not arranged, the working principle of the invention is as follows:
when the electromagnetic directional valve 80 is powered off, the oil passing cavity 23 is communicated with the oil pan 60 through the electromagnetic directional valve 80 and the overflow pressure maintaining valve 50, and is communicated with an engine oil way through the pressure reducing valve 40.
The relief pressure of the relief pressure-retaining valve 50 is equal to or slightly smaller than the pressure after the relief of the relief valve 40, and is not larger than the pressure of the hydraulic oil that urges the sliding plunger 71 against the elastic force of the plunger return spring 72.
When the electromagnetic directional valve 80 is electrified, the oil passing cavity 23 is communicated with an engine oil way through the electromagnetic directional valve 80 and the one-way valve 100.
The plunger return spring 72 in the sliding plunger mechanism is designed to ensure that when the oil pressure of the oil passing cavity 23 is the oil pressure of the oil outlet P2 of the pressure reducing valve 40, the thrust force of the oil pressure on the sliding plunger 71 is smaller than the elastic force of the plunger return spring 72; when the oil pressure of the oil passing chamber 23 is the oil pressure of the oil inlet P1 of the relief valve 40, the thrust force of the oil pressure on the sliding plunger 71 is larger than the elastic force of the plunger return spring 72.
When the engine is operating normally, the electromagnetic directional valve 80 is powered off, the pressure of the oil passage chamber 23 of the camshaft 20 is the oil pressure of the oil outlet P2 of the relief valve 40, the thrust force to the sliding plunger 71 cannot overcome the elastic force of the plunger return spring 72, and the sliding plunger 71 does not move, as shown in fig. 8 and 9.
When the engine enters a braking state in a cylinder, the electromagnetic directional valve 80 is electrified, engine oil pressure enters the oil passing cavity 23 through the one-way valve 100 and the electromagnetic directional valve 80, the oil pressure of the oil passing cavity 23 is the oil pressure of an oil inlet P1 of the pressure reducing valve 40, the thrust of the oil pressure to the sliding plunger 71 overcomes the elastic force of the plunger return spring 72, the sliding plunger 71 moves, as shown in fig. 10, the thrust of the oil pressure of the oil passing cavity 23 to the sliding plunger 71 is smaller than the resultant force of the plunger return spring 72 and the valve spring 11, and the top of the sliding plunger 71 is in contact with the valve tappet 15 but can not push the tappet 15 to move; the exhaust cam 22 continues to rotate to the position shown in fig. 11, at which time the sliding plunger 71 continues to move under the oil pressure of the oil inlet P1 of the relief valve 40, with the top projecting from the cam surface. When the plunger is rotated to the position shown in fig. 12, the through oil chamber 23 becomes a closed space due to the check valve 100, the incompressibility of the hydraulic oil, and the sliding plunger 71 is kept at the protruding position to drive the tappet 15 to move, so that the pressure is released.
The engine of this embodiment is a six-cylinder four-stroke engine, and those sliding plungers 71 that hit the lifter 15 or the valve cap (the cam shaft overhead structure) are blocked in the mounting holes, and only when all the lifters 15 or the valve caps of the six cylinders are in contact with the base circle of the exhaust cam 22, the sliding plungers 71 in the exhaust cam 22 may be fully extended without blocking the lifter 15 or the valve cap.
As shown in fig. 1 and 13, in order to avoid the "start" phenomenon mentioned in the background art of the sliding plungers 71 of six cylinders and to increase the oil filling speed of the oil passing chamber, the present embodiment sets a throttle device 26a in the oil passing chamber 23, the left side of the throttle device 26a is 1 cylinder, 2 cylinder and 3 cylinder of the engine, the right side is 4 cylinder, 5 cylinder and 6 cylinder of the engine, the working sequence of the engine is 1 cylinder-5 cylinder-3 cylinder-6 cylinder-2 cylinder-4 cylinder, and therefore, the working sequence of the sliding plungers can be simply understood as left-right- … …, and one cycle is left and right. For convenience of description, the oil passage chamber on the left side of the throttle device 26a is simply referred to as "left chamber", and the oil passage chamber on the right side of the throttle device 26a is simply referred to as "right chamber". In fig. 13 and the following fig. 14 and 15, the two sliding plunger mechanisms 70 in the left and right chambers should actually differ by a certain phase, which is a multiple of 60 ° for a six-cylinder engine, and the illustrated state is merely for convenience of explanation of the operation principle.
As shown in fig. 13 and 16, the specific structure of the throttling device 26a is that a throttling channel is provided in the device body 26a3, the throttling channel has a first opening end close to the rotary oil inlet interface device 30 and a second opening end far away from the rotary oil inlet interface device 30, the throttling channel is provided with a conical surface, a valve ball 26a2 is installed in the throttling channel, the valve ball 26a2 is matched with the conical surface, a throttling pressure release spring 26a4 is arranged in the throttling channel between the valve ball 26a2 and the first opening end, and a valve ball limiting structure is arranged in the throttling channel between the valve ball 26a2 and the second opening end, and specifically, the valve ball limiting structure is a limiting pin 26a1.
When the engine enters the in-cylinder braking state, the electromagnetic directional valve 80 is energized, and the oil supply device supplies oil to the oil passage chamber 23. When the sliding plunger in the left cavity does not lean against the tappet 15, engine oil enters the left cavity from the right cavity through the throttling device 26a to supply oil to the left cavity, and the sliding plunger in the left cavity is jacked up; when the jacked sliding plunger in the left chamber is jacked by the tappet 15, the oil pressure in the left chamber increases, the valve ball 26a2 seals the tapered surface, the throttle passage is blocked, the oil in the left chamber cannot enter the right chamber, and the jacked sliding plunger is kept in a convex state, at this time, engine oil can flow from the oil supply device into the right chamber through the rotary oil inlet port device 30, and the sliding plunger in the right chamber is jacked. After a limited number of cycles, the oil passage chamber 23 is rapidly filled. When the electromagnetic directional valve 80 is powered off, the oil passing cavity 23 is communicated with the oil pan 60 through the overflow pressure maintaining valve 50 for pressure relief, and the opening pressure of the throttling pressure relief spring 26a4 is designed to be larger than the pressure difference between Zuo Qiangya force (the pressure when the tappet is not propped against the sliding plunger) and the pressure of the right cavity, and the hydraulic oil in the left cavity flows through a gap between the valve ball 26a2 and the conical surface for pressure relief to the right cavity.
In a sense, the restriction 26a is a normally open one-way restriction that will close only when subjected to the pressure of the tappet 15. The advantage of the throttle device 26a is that the flow area between the ball and the conical surface is large and the oil filling and draining speed is high. The disadvantage is that if the throttling pressure relief spring 26a4 has adhesion and other problems during use, pressure relief may be unsmooth.
In this embodiment, since the throttle device 26a is provided, the oil in the left chamber is not pressed back to the right chamber; because the check valve 100 is provided, the oil in the right chamber is not pressed back into the oil passage. The phenomenon of sliding the plunger, namely the phenomenon of surging is greatly reduced, the oil filling speed of the oil passing cavity is increased, and the response time of in-cylinder braking is shortened. Based on the above principle, a plurality of throttle devices can be arranged in the oil passing cavity to divide the oil passing cavity 23 into a plurality of cavities, so that the response speed of in-cylinder braking can be faster.
The technical effects achieved by the two sets of oil feeding devices and the two sets of rotary oil feeding interface devices 30 described in the Chinese patent application CN201911000047.7 are achieved by only one set of oil feeding device and one set of rotary oil feeding interface device 30, and the rotary oil feeding device is more compact in structure and lower in cost.
Example 2
The structure of embodiment 2 is substantially the same as that of embodiment 1, except that the structure of the throttle device is different. As shown in fig. 14 and 17, the throttle device 26b includes a device body 26b1 mounted in the through oil chamber 23, and the device body 26b1 is provided with an orifice 26b2.
When the oil in the left chamber flows to the right chamber, the flow rate decreases due to the action of the orifice 26b2, and at this time, the engine oil may also be filled into a part of the right chamber through the electromagnetic directional valve 80 (i.e., the left chamber and the engine oil passage simultaneously fill the right chamber). In the next cycle, when the sliding plunger that has been protruded in the right chamber abuts against the tappet, the right chamber oil flows to the left chamber through the orifice 26b 2. The repeated circulation is performed, and the engine oil passage can supply a part of engine oil to the oil passage 23 in each circulation, so that the oil passage 23 can be filled up finally by a limited number of circulation.
When the electromagnetic valve is powered off, the oil passing cavity 23 is communicated with the oil pan 60 through the overflow pressure maintaining valve 50 for pressure relief, and hydraulic oil in the left cavity is relieved through the drain hole 26b 2.
The advantage of the restriction 26b is that it is simple in construction but has a slow rate of filling and draining.
Example 3
The structure of embodiment 3 is substantially the same as that of embodiment 1, except that the structure of the throttle device is different. As shown in fig. 15 and 18, as in embodiment 1, the throttle device 26c also includes a device body 26c3, a valve ball 26c2, a throttle pressure release spring 26c4, and a stopper pin 26a1, where the device body 26c3 is provided with a throttle channel having a first opening end close to the rotary oil inlet port device 30 and a second opening end far away from the rotary oil inlet port device 30, and the difference is that the valve ball 26c2 is provided with an orifice 26c5 communicating the first opening end and the second opening end, and when the throttle pressure release spring 26a4 is in use, adhesion and other problems occur, the throttle pressure can be released through the orifice 26c5, so that the reliability thereof is improved.
The invention is applicable to camshaft-mounted engines as well as camshaft-mounted engines, where, when applied in a camshaft-mounted engine, the valve bonnet is in contact with the cam, rather than the tappet.
The present invention is not limited to the above embodiments, and all modifications based on the concept, principle, structure and method of the present invention are included in the scope of the present invention.
Claims (8)
1. An in-cylinder compression release engine brake apparatus comprising:
The valve mechanism comprises a cam shaft, wherein the cam shaft is provided with a plurality of exhaust cams; it is characterized in that the method comprises the steps of,
The camshaft is provided with a through oil cavity along the axial direction, the camshaft is provided with a rotary oil inlet interface device, the through oil cavity is communicated with a set of oil supply device only through a set of rotary oil inlet interface device, the exhaust cam is provided with a mounting hole along the radial direction, the mounting hole is communicated with the through oil cavity, and a sliding plunger mechanism is arranged in the mounting hole;
The oil supply device comprises an electromagnetic reversing valve, a pressure relief oil circuit and a one-way oil circuit, wherein when the electromagnetic reversing valve is powered off, the oil through cavity is communicated with the oil pan through the pressure relief oil circuit and is communicated with an engine oil circuit through the pressure relief oil circuit; when the electromagnetic reversing valve is electrified, the engine oil circuit supplies oil to the oil through the one-way oil circuit, and the sliding plunger mechanism stretches out of the cam surface of the exhaust cam to form a braking bulge when the sliding plunger mechanism is not blocked by a tappet or a valve protecting cap of the valve mechanism;
The device comprises a device body arranged in the oil through cavity, a throttling channel is formed in the device body, the throttling channel is provided with a first opening end close to the rotary oil inlet interface device and a second opening end far away from the rotary oil inlet interface device, the throttling channel is provided with a conical surface, a valve ball is arranged in the throttling channel and is matched with the conical surface, a throttling pressure release spring is arranged in the throttling channel between the valve ball and the first opening end, and a valve ball limiting structure is arranged in the throttling channel between the valve ball and the second opening end;
The sliding plunger mechanism comprises a sliding plunger, a plunger return spring, a pin shaft and a plug, wherein the mounting hole is a stepped hole, the stepped hole comprises a large hole and a small hole, the small hole penetrates through a cam shaft part on one side of the oil passing cavity in the radial direction and forms a blind hole on the cam shaft part on the other side of the oil passing cavity, the large hole is recessed from the oil passing cavity to the opening direction of the small hole, the pin shaft is mounted in the large hole, the sliding plunger is mounted in the small hole, a spring mounting hole is axially formed in the sliding plunger, a long slot hole is axially formed in the sliding plunger, the pin shaft is slidably arranged in the long slot hole, the plunger return spring is clamped in the spring mounting hole by the pin shaft, when the oil passing cavity is in a pressure relief state, the plunger return spring pushes the sliding plunger against the bottom of the blind hole, and the plug is screwed on the outer opening end of the spring mounting hole and seals the spring mounting hole;
the rotary oil inlet interface device comprises a fixed oil sleeve, the camshaft is provided with an oil inlet journal, the oil inlet journal is rotatably and hermetically arranged on the fixed oil sleeve, an annular oil groove is formed in the outer peripheral surface of the oil inlet journal, the annular oil groove is communicated with the oil through cavity, an oil through hole is formed in the fixed oil sleeve, the oil through hole is communicated with the annular oil groove, an end cover for sealing an opening of the oil through cavity is arranged at the end of the camshaft, and an annular flange for limiting the axial movement of the fixed oil sleeve is arranged on the end cover.
2. The compression-release type engine in-cylinder brake apparatus as defined in claim 1, wherein said valve ball is provided with an orifice communicating said first open end and said second open end.
3. The compression-release type engine in-cylinder brake apparatus as defined in claim 1, wherein said throttle means includes a device body installed in said through oil chamber, said device body being provided with an orifice.
4. The compression-release type engine in-cylinder brake apparatus as defined in claim 1, wherein said rotary oil inlet port means is provided at an open end portion of said oil passage chamber.
5. The compression-release type engine in-cylinder brake apparatus according to claim 1, wherein the electromagnetic directional valve is a two-position three-way electromagnetic directional valve.
6. The compression-release type engine in-cylinder brake apparatus according to claim 1, wherein a check valve is provided in the check oil passage, a relief valve is provided in the relief oil passage, and an overflow pressure retaining valve is provided in the relief oil passage.
7. The compression-release type engine in-cylinder brake apparatus according to claim 6, wherein the relief pressure retaining valve has the same structure as the pressure reducing valve.
8. The compression-release type engine in-cylinder brake apparatus according to claim 7, wherein the pressure reducing valve comprises a valve body, a valve cavity is provided with an oil inlet, an oil outlet and a pressure regulating port, a valve ball and a pressure regulating spring are installed in the valve cavity, the pressure regulating port is screwed with a pressure regulating screw, and the valve ball is elastically pressed against the oil inlet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201911081759.6A CN110645066B (en) | 2019-11-07 | 2019-11-07 | Compression release type engine in-cylinder braking device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911081759.6A CN110645066B (en) | 2019-11-07 | 2019-11-07 | Compression release type engine in-cylinder braking device |
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| CN110645066A CN110645066A (en) | 2020-01-03 |
| CN110645066B true CN110645066B (en) | 2024-05-10 |
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| JP2005014632A (en) * | 2003-06-23 | 2005-01-20 | Hitachi Unisia Automotive Ltd | Brake hydraulic pressure control device |
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| CN110645066A (en) | 2020-01-03 |
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