阅读说明：本技术 压缩释放式发动机缸内制动装置 (Compression release type in-cylinder brake device for engine ) 是由 王立峰 王孟晓 王秀强 吴贝贝 吴龙龙 从田增 吴鹏超 苏明涛 衣金水 于 2019-11-07 设计创作，主要内容包括：本发明公开了一种压缩释放式发动机缸内制动装置,包括：凸轮轴设置有若干个排气凸轮；凸轮轴沿轴向开设有通油腔,通油腔仅通过一套旋转进油接口装置与一套供油装置连通,排气凸轮沿径向开设有安装孔,安装孔内设置有滑动柱塞机构,通油腔中设置有节流装置。本发明不仅提高了发动机工作的可靠性,而且在发动机进入缸内制动状态后,提高了供油装置对凸轮轴的通油腔的充油速度,使所有滑动柱塞更快的凸出形成制动凸起,减少了缸内制动的响应时间,结构简单紧凑,成本低。(The invention discloses a compression release type engine in-cylinder brake device, comprising: the camshaft is provided with a plurality of exhaust cams; the camshaft is provided with an oil through cavity along the axial direction, the oil through 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, a sliding plunger mechanism is arranged in the mounting hole, and a throttling device is arranged in the oil through cavity. 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 camshaft after the engine enters the in-cylinder braking state, so that all sliding plungers protrude more quickly to form braking bulges, the response time of in-cylinder braking is reduced, the structure is simple and compact, and the cost is low.)

1. A compression-release in-cylinder brake apparatus for an engine, comprising:

the valve actuating mechanism comprises a camshaft, and the camshaft is provided with a plurality of exhaust cams; it is characterized in that the preparation method is characterized in that,

the exhaust cam is provided with a mounting hole along the radial direction, the mounting hole is communicated with the oil through cavity, and a sliding plunger mechanism is arranged in the mounting hole;

the oil supply device comprises an electromagnetic directional valve, a pressure relief oil way and a one-way oil way, and when the electromagnetic directional valve is powered off, the oil through 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; when the electromagnetic directional valve is electrified, the oil path of the engine supplies oil to the oil through cavity through the one-way oil path, and the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a braking bulge when not blocked by a tappet or a valve protective cap of the valve mechanism;

and a throttling device is arranged in the oil through cavity.

2. The compression-release engine in-cylinder brake device according to claim 1, wherein the throttle device includes a device body installed in the oil passage cavity, the device body is provided with a throttle passage, the throttle passage has 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 throttle passage is provided with a conical surface, a valve ball is installed in the throttle passage, the valve ball is matched with the conical surface, a throttle pressure-relief spring is arranged in the throttle passage between the valve ball and the first opening end, and a valve ball limiting structure is arranged in the throttle passage between the valve ball and the second opening end.

3. The compression-release engine in-cylinder brake apparatus as defined in claim 2, wherein said valve ball is provided with an orifice communicating said first open end and said second open end.

4. The compression-release engine in-cylinder brake apparatus as defined in claim 1, wherein said throttle means includes a fitting body fitted in said oil passage chamber, said fitting body being provided with a throttle hole.

5. The compression-release engine in-cylinder brake apparatus as defined in claim 1, wherein said sliding plunger mechanism includes a sliding plunger, a plunger return spring, a pin and a plug, said mounting hole is a stepped hole, said stepped hole includes a large hole and a small hole, said small hole radially penetrates a portion of said camshaft on one side of said oil passage chamber and forms a blind hole in a portion of said camshaft on the other side of said oil passage chamber, said large hole is recessed from said oil passage chamber toward an opening direction of said small hole, said pin is mounted in said large hole, said sliding plunger is mounted in said small hole, said sliding plunger is axially provided with a spring mounting hole and radially provided with a long groove hole, said pin is slidably provided in said long groove hole, said plunger return spring is sandwiched in said spring mounting hole by said pin, when said oil passage chamber is in a pressure-released state, the plunger return spring enables the sliding plunger to abut against the bottom of the blind hole, and the plug is screwed at the outer opening end of the spring mounting hole and seals the spring mounting hole.

6. The compression-release engine in-cylinder brake apparatus as defined in claim 1, wherein said rotary oil-intake interface means is provided at an open end of said oil-through chamber.

7. The in-cylinder brake device of a compression-release engine according to claim 1, wherein the rotary oil inlet interface device includes a fixed oil jacket, the camshaft is provided with an oil inlet journal, the oil inlet journal is rotatably and sealingly mounted to the fixed oil jacket, an annular oil groove is formed in an outer circumferential surface of the oil inlet journal, the annular oil groove is communicated with the oil through cavity, the fixed oil jacket is provided with an oil through hole, the oil through hole is communicated with the annular oil groove, an end cap for sealing an opening of the oil through cavity is provided at an end of the camshaft, and the end cap is provided with an annular flange for restricting axial movement of the fixed oil jacket.

8. The compression-release engine in-cylinder brake apparatus as defined in claim 1, wherein said electromagnetic directional valve is a two-position three-way electromagnetic directional valve.

9. The compression-release engine in-cylinder brake apparatus according to claim 1, wherein a check valve is provided in the check oil passage, a pressure reducing valve is provided in the pressure reducing oil passage, and an overflow pressure retaining valve is provided in the pressure reducing oil passage.

10. The compression-release engine in-cylinder brake apparatus as defined in claim 9, wherein the relief pressure retaining valve has the same structure as the pressure reducing valve.

11. The compression-release engine in-cylinder brake apparatus as defined in claim 10, wherein said pressure-reducing valve includes a valve body, said valve body defines a valve cavity, said valve cavity defines an oil inlet, an oil outlet and a pressure-regulating port, said valve cavity is internally installed with a valve ball and a pressure-regulating spring, said pressure-regulating port is screwed with a pressure-regulating screw, and said valve ball is elastically pressed against said oil inlet.

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-release braking, compression release braking and the like, wherein the compression release braking technology is the best technology of the braking performance of the engine at present, and the basic principle is as follows: when the engine is dragged backwards, the piston compresses the gas in the cylinder to generate braking power in the process of ascending the compression stroke piston. Before the compression top dead center, the compression release type brake device drives the exhaust valve to open a certain opening degree, compressed high-temperature and high-pressure charging in the cylinder is discharged, at the moment, the pressure in the cylinder is rapidly reduced, after a certain crank angle, the exhaust valve is closed again, the piston moves downwards, and as the charging in the cylinder is greatly reduced, the working of the charging in the cylinder on the piston is also greatly reduced, and the counter braking power of the compression charging in the cylinder on the piston is reduced or eliminated.

Chinese utility model patent CN201241740Y discloses a four-stroke internal combustion engine rocking arm integrated form arresting gear, it sets up two braking archs on the control cam for realize opening the (air) intake valve before the intake stroke finishes and increase the air input, open the cylinder braking that the exhaust valve released pressure realized the engine before the compression stroke finishes, in order to offset the valve lift that the arch arouses of braking when the engine normal operating, need set up hydraulic control's clearance compensation mechanism on the rocking arm. Because the normal operating state accounts for the vast majority of the operating state of the whole engine, the clearance compensation mechanism is in the working state in the vast majority of the operating time of the engine, higher requirements on reliability and the like are provided, and the structure is more complex.

In order to solve the technical problems and improve the reliability of corresponding parts of an engine, the Chinese patent application CN201911000047.7 proposes a compression release type engine cylinder inner braking device, wherein an oil through cavity is arranged on a cam shaft of a valve actuating mechanism, a mounting hole is arranged on an exhaust cam, the oil through 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 directional valve of the oil supply device is powered off, the oil through cavity is communicated with the oil pan through the pressure relief oil way and is communicated with the engine oil way through the pressure relief oil way; when the electromagnetic directional valve is electrified, the oil path supplies oil to the oil passage chamber through the one-way oil path, and the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a braking bulge when not blocked by the tappet.

However, in the test, it was found that, in the case of a multi-cylinder engine having six or more cylinders, since the cylinders of the engine are sequentially operated, after the engine enters an in-cylinder braking state, those sliding plungers which are not stopped by the lifter or the valve cap are extended to form braking projections, and those sliding plungers which are stopped by the lifter or the valve cap are not extended to form braking projections. Under the condition that the oil through cavity is not filled with oil, once the blocked sliding plungers pass through the tappet or the valve cap along with the rotation of the camshaft, the blocked sliding plungers extend under the action of the oil pressure of the engine oil to form a certain oil containing space in the mounting hole, at the moment or after a little time, when the sliding plungers which extend out to form the braking bulge are pressed by the tappet or the valve cap again, the oil in the oil through cavity is subjected to back pressure, the pressure is far greater than the pressure of the engine oil, the part of the back pressure oil cannot return to the engine oil way through the one-way oil way, but can flow back to the oil containing space formed by the extension of the sliding plungers, and thus the phenomenon that the sliding plungers are prone is generated within a period of time, so that the oil filling process of the oil supply device to the oil through cavity is very slow, and only when all the sliding plungers extend out of the mounting hole to form the braking bulge, after the oil through cavity is filled with oil, the phenomenon can be stopped, and the sliding plunger can really play a role in braking the protrusion.

In order to improve the oil filling speed of the oil supply device to the oil through cavity after the engine enters the in-cylinder braking state, so that all sliding plungers are protruded more quickly to form braking protrusions and the response time of in-cylinder braking is shortened, the chinese patent application CN201911000047.7 also provides another implementation manner, wherein a plug is arranged in the oil through cavity, the plug divides the oil through cavity into two parts, two ends of the oil through 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 respectively. Because two oil supply devices can respectively supply oil, the oil supply time of the oil through cavities of the two parts can be staggered, the actual working condition of sequential work of each cylinder of the engine is adapted, one oil through cavity corresponding to six sliding plungers is changed into each oil through cavity corresponding to three sliding plungers, and the contact time of all tappets and a cam base circle is longer in the same period, so that the sliding plungers can quickly protrude to form a braking bulge after entering a braking state in the cylinder. However, this structure requires two sets of oil supply devices, occupies more engine space, and is also higher in cost.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the compression release type engine cylinder braking device to improve the working reliability of the engine, and after the engine enters the in-cylinder braking state, the oil filling speed of the oil supply device to the oil through cavity of the camshaft is improved, all sliding plungers are enabled to protrude more quickly to form braking bulges, the response time of in-cylinder braking is shortened, the structure is simple and compact, and the cost is low.

In order to solve the above technical problem, the present invention provides a compression release type in-cylinder brake device for an engine, comprising: the valve actuating mechanism comprises a camshaft, and the camshaft is provided with a plurality of exhaust cams; the exhaust cam is provided with a mounting hole along the radial direction, the mounting hole is communicated with the oil through cavity, and a sliding plunger mechanism is arranged in the mounting hole; the oil supply device comprises an electromagnetic directional valve, a pressure relief oil way and a one-way oil way, and when the electromagnetic directional valve is powered off, the oil through 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; when the electromagnetic directional valve is electrified, the oil path of the engine supplies oil to the oil through cavity through the one-way oil path, and the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a braking bulge when not blocked by a tappet or a valve protective cap of the valve mechanism; and a throttling device is arranged in the oil through cavity.

The throttling device comprises a device body arranged in the oil through cavity, the device body is provided with a throttling channel, 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 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 open end and the second open end.

The throttling device comprises a device body arranged in the oil through cavity, and the throttling hole is formed in the device body.

Wherein, the sliding plunger mechanism comprises a sliding plunger, a plunger return spring, a pin shaft and a plug, the mounting hole is a stepped hole, the stepped hole comprises a big hole and a small hole, the small hole radially penetrates through the part of the cam shaft at one side of the oil through cavity and forms a blind hole at the part of the cam shaft at the other side of the oil through cavity, the big hole is sunken from the oil through cavity to the opening direction of the small hole, the pin shaft is mounted in the big hole, the sliding plunger is mounted in the small hole, the sliding plunger is axially provided with a spring mounting hole and radially provided with a slotted hole, the pin shaft is slidably arranged in the slotted hole, the plunger return spring is clamped in the spring mounting hole by the pin shaft, when the oil through cavity is in a pressure relief state, the plunger return spring pushes the sliding plunger against the bottom of the blind hole, the plug is screwed at the outer opening end of the spring mounting hole and seals the spring mounting hole.

The rotary oil inlet interface device is arranged at the opening end part of the oil through cavity.

The rotary oil inlet interface device comprises a fixed oil sleeve, the camshaft is provided with an oil inlet shaft neck, the oil inlet shaft neck is rotatably and hermetically mounted on the fixed oil sleeve, an annular oil groove is formed in the peripheral surface of the oil inlet shaft neck, the annular oil groove is communicated with the oil through cavity, the fixed oil sleeve is provided with an oil through hole, the oil through hole is communicated with the annular oil groove, an end cover for sealing the opening of the oil through cavity is arranged at the end part of the camshaft, and the end cover is provided with an annular flange for limiting the axial movement of the fixed oil sleeve.

Wherein, the electromagnetic directional valve is a two-position three-way electromagnetic directional valve.

The pressure relief oil circuit is characterized in that a one-way valve is arranged in the one-way oil circuit, a pressure relief valve is arranged in the pressure relief oil circuit, and an overflow pressure retaining valve is arranged in the pressure relief oil circuit.

The structure of the overflow pressure retaining valve is the same as that of the pressure reducing valve.

The pressure reducing valve comprises a valve body, the valve body is provided with a valve cavity, the 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, a pressure regulating screw is screwed in 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 reversing valve is powered off, the oil through cavity is communicated with the oil pan through the pressure relief oil way and is communicated with an engine oil way of the engine through the pressure reduction oil way, and at the moment, the oil pressure in the oil through cavity is insufficient to push the sliding plunger mechanism to act; when the engine enters an in-cylinder braking mode, the electromagnetic directional valve is electrified, the oil circuit of the engine supplies oil to the oil through cavity through the one-way oil circuit, the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a braking bulge when not blocked by a tappet or a valve protective cap of the valve mechanism, and the braking bulge pushes the valve tappet or the valve protective cap to open an exhaust valve, so that in-cylinder braking is completed. Compared with the prior art, the sliding plunger extends out of the cam surface of the exhaust cam only when the engine is in the in-cylinder braking mode, the working time of the sliding plunger mechanism is very short, and 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 the pressure of an oil circuit without adopting a supercharging mechanism, so the structure is simpler. The invention is suitable for the engine with the lower camshaft and the engine with the upper camshaft.

2) In the invention, because the throttling device is arranged in the oil through cavity, the oil in the left cavity can not be pressed back to the right cavity or only a small part of the oil can be pressed back through the throttling hole, so that the phenomenon of 'this lifting' of the sliding plunger is greatly reduced, the oil filling speed of the oil through cavity is accelerated, and the response time of braking in the cylinder is shortened.

3) In the invention, the effects which can be achieved by two sets of oil inlet devices and two sets of rotary oil inlet interface devices can be achieved by only one set of oil supply device and one set of rotary oil inlet interface device, the structure is more compact, and the cost is lower.

Drawings

FIG. 1 is a schematic structural view of an embodiment 1 of the in-cylinder brake apparatus for a compression-release engine of the present invention;

FIG. 2 is a hydraulic schematic of the oil supply of FIG. 1;

FIG. 3 is an enlarged view of a portion of FIG. 1 at I;

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 taken at A-A of FIG. 1;

FIG. 6 is a schematic view of the portion of the cam shaft of FIG. 3 with the sliding plunger mechanism removed;

FIG. 7 is a cross-sectional view of the relief valve of FIG. 2;

fig. 8 is a reference view showing an operating state in which the sliding plunger mechanism is in a position opposed to the lifter in normal operation of the engine in embodiment 1;

fig. 9 is a reference view showing an operating state in which the sliding plunger mechanism is in a position deviated from the tappet position in the normal operation of the engine in embodiment 1;

fig. 10 is a reference diagram of an operating state of the sliding plunger mechanism at a position opposed to the lifter upon entry of the engine into the in-cylinder braking mode in embodiment 1;

fig. 11 is a reference diagram of an operating state of the sliding plunger mechanism at the position deviated from the lifter position when the engine is in the in-cylinder braking mode in embodiment 1;

fig. 12 is a reference view showing an operating state in which the sliding plunger mechanism is extended and returned to a position opposite to the lifter in the in-cylinder braking mode of the engine according to embodiment 1;

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 view of the working principle of embodiment 3;

fig. 16 is an enlarged longitudinal sectional view of the throttle device in embodiment 1;

fig. 17 is an enlarged longitudinal sectional view of the throttle device in embodiment 2;

fig. 18 is an enlarged longitudinal sectional view of the throttle device in embodiment 3;

in the figure: 10-exhaust valve, 11-valve spring, 12-valve rocker arm, 13-rocker shaft, 14-push rod, 15-tappet, 20-camshaft, 21-intake cam, 22-exhaust cam, 23-oil through cavity, 24-annular oil groove, 25-timing gear, 26-throttling device, 26a 1-limit pin, 26a 2-valve ball, 26a 3-device body, 26a 4-throttling pressure relief spring, 26 b-throttling device, 26b 1-throttling hole, 26 c-throttling device, 26c 1-limit pin, 26c 2-valve ball, 26c 3-device body, 26c 4-throttling spring, 26c 5-throttling 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 retaining valve, 60-oil pan, 70-sliding plunger mechanism, 71-sliding plunger, 711-spring mounting hole, 712-long slotted hole, 72-plunger return spring, 73-pin shaft, 74-plug, 80-electromagnetic reversing valve, phix-big hole, phiy-small hole and 100-one-way valve.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.