Oil-pressurized compression-release engine cylinder brake device

Abstract

The present invention discloses an oil-boosted compression-release type in-cylinder braking device for an engine, comprising: a camshaft, an oil passage cavity is opened in the axial direction of the camshaft, a rotary oil inlet interface device is provided on the camshaft, the rotary oil inlet interface device is communicated with an oil supply device, and the oil supply device comprises an oil-boosting oil circuit; an exhaust cam of the camshaft is opened in the radial direction with a mounting hole communicated with the oil passage cavity, a sliding plunger mechanism is arranged in the mounting hole; the present invention supplies oil to the oil passage cavity of the camshaft through the oil-boosting oil circuit only when the engine is in an in-cylinder braking mode, and the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a braking protrusion, thereby realizing in-cylinder braking; when the engine is in a normal working state, the oil is decompressed, and the sliding plunger mechanism is recovered in the mounting hole of the exhaust cam; the working time of the sliding plunger mechanism is very short, and the reliability of the engine operation is higher.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to an oil-pressurized compression-release type in-cylinder brake device for an engine. Background Art

[0002] During normal engine operation, the camshaft rotates 360 degrees every time, and the engine completes four working cycles of intake, compression, power and exhaust. At the end of the compression stroke, the fuel is sprayed into the cylinder and burned, and then works externally in the subsequent expansion stroke.

[0003] Engine cylinder braking is a form of auxiliary braking for the whole vehicle. The contribution of engine cylinder braking is that it can not only improve the braking capacity of the whole vehicle, but also reduce the braking load of the main brake of the whole vehicle. When the engine cylinder brake is in use, the exhaust valve needs to be opened with a small lift when the engine is close to the top dead center during the compression stroke, and the high-pressure gas compressed in the cylinder is quickly released. The pressure in the cylinder is quickly reduced to reduce the energy of the power stroke. Therefore, in the following power stroke, the engine basically does not work externally, thereby slowing down the engine and achieving the purpose of engine cylinder braking.

[0004] The Chinese invention patent with the announcement number CN201241740Y and the name of "A rocker arm integrated brake device for a four-stroke internal combustion engine" discloses an engine in-cylinder brake device, which is provided with two brake lobes on the exhaust cam, which is used to open the intake valve before the end of the intake stroke to increase the intake volume, and open the exhaust valve before the end of the compression stroke to release the pressure to achieve the in-cylinder brake of the engine. In order to offset the valve lift caused by the brake lobes when the engine is running normally, it is necessary to set a hydraulically controlled clearance compensation mechanism on the rocker arm. Since the normal operation state accounts for the vast majority of the entire engine operation state, the clearance compensation mechanism is in working state for most of the time when the engine is running, which puts forward high requirements on reliability, etc., and the structure is relatively complex. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide an oil-pressurized compression-release engine cylinder brake device to improve the reliability of engine operation.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: a compression-release type engine cylinder brake device with oil boost, comprising:

[0007] A camshaft, wherein the camshaft is provided with a plurality of exhaust cams; the camshaft is provided with an oil passage cavity along the axial direction, and the camshaft is provided with a rotary oil inlet interface device, wherein the rotary oil inlet interface device is connected to an oil supply device, and the oil supply device includes an oil boost oil circuit;

[0008] The exhaust cam is provided with a mounting hole in the radial direction, the mounting hole is communicated with the oil passage chamber, a sliding plunger mechanism is arranged in the mounting hole, when oil is supplied to the oil passage chamber through the oil boost oil circuit, the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a braking protrusion.

[0009] In which, the sliding plunger mechanism includes a sliding plunger, a plunger return spring, a pin shaft and a wire plug, the mounting hole is a stepped hole, the stepped hole includes a large hole and a small hole, the small hole radially penetrates the camshaft part on one side of the oil through chamber and forms a blind hole on the camshaft part on the other side of the oil through chamber, the large hole is recessed from the oil through chamber 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, the sliding plunger is provided with a spring mounting hole in the axial direction and a long slot hole in the radial direction, 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 through chamber is in a pressure relief state, the plunger return spring presses the sliding plunger against the bottom of the blind hole, and the wire plug is screwed on the outer opening end of the spring mounting hole and seals the spring mounting hole.

[0010] Wherein, the rotating oil inlet interface device is arranged at the open end of the oil passage chamber; the rotating oil inlet interface device includes a fixed oil sleeve, the camshaft is provided with an oil inlet journal, the oil inlet journal rotation seal is installed on the fixed oil sleeve, the outer peripheral surface of the oil inlet journal is provided with an annular oil groove, the annular oil groove is communicated with the oil passage chamber, the fixed oil sleeve is provided with an oil through hole, the oil through hole is communicated with the annular oil groove; the end of the camshaft is provided with an end cover for sealing the opening of the oil passage chamber.

[0011] Wherein, a pressure sensor is arranged in the oil circuit between the rotating oil inlet interface device and the engine oil supply device.

[0012] Among them, the oil boost circuit includes: a first solenoid reversing valve, a plunger boosting cylinder, and a second solenoid reversing valve connected in sequence, the first solenoid reversing valve is connected to the engine oil circuit, and the second solenoid reversing valve is connected to the rotating oil inlet interface device.

[0013] Among them, the plunger booster cylinder includes: a plunger cylinder body, a cover plate, a small-diameter plunger, a large-diameter plunger, and a plunger return spring; the plunger cylinder body is provided with a through small-diameter hole and a large-diameter hole along its axial direction, and the cover plate is fixed to the end of the plunger cylinder body; the small-diameter plunger is slidably installed in the small-diameter hole, and a small oil chamber is formed between the small-diameter hole, the small-diameter plunger and the cover plate, and the small oil chamber is connected to the second electromagnetic reversing valve; the large-diameter plunger is slidably installed in the large-diameter hole, and a large oil chamber is formed between the large-diameter hole, the large-diameter plunger and the cover plate, and the large oil chamber is connected to the first electromagnetic reversing valve; the plunger return spring is sleeved on the small-diameter plunger, and is clamped between the bottom of the large-diameter hole and the large-diameter plunger, and the chamber where the plunger return spring is located is an oil-free chamber.

[0014] Wherein, the plunger cylinder body is provided with an air leakage hole communicated with the oil-free chamber.

[0015] Wherein, a first one-way valve is arranged in the oil circuit connecting the small oil chamber and the second electromagnetic reversing valve.

[0016] Wherein, the oil supply device further includes an oil pressure reducing oil circuit connected in parallel with the oil pressure increasing oil circuit.

[0017] Wherein, the oil pressure reducing oil circuit includes a pressure reducing valve, and the pressure reducing valve is arranged in the oil circuit between the second solenoid reversing valve and the engine oil circuit.

[0018] Wherein, the pressure reducing valve includes: a valve body, a valve ball, a pressure regulating spring and a pressure regulating screw. The valve body is provided with an oil inlet and an oil outlet connected with its valve cavity. The valve ball and the pressure regulating spring are arranged in the valve cavity. The valve ball is sealed at the oil inlet. The pressure regulating screw is threadedly connected to the valve body. One end of the pressure regulating spring abuts against the valve ball, and the other end of the pressure regulating spring abuts against the pressure regulating screw.

[0019] Wherein, the oil supply device also includes a pressure relief oil circuit, and the pressure relief oil circuit includes a camshaft oil chamber pressure relief oil circuit and a boost cylinder large oil chamber pressure relief oil circuit.

[0020] Among them, the boost cylinder large oil chamber pressure relief oil circuit includes a first overflow pressure maintaining valve, which is arranged in the oil circuit between the first solenoid reversing valve and the oil pan; the camshaft oil chamber pressure relief oil circuit includes a second overflow pressure maintaining valve, which is arranged in the oil circuit between the second solenoid reversing valve and the oil pan.

[0021] Wherein, the oil supply device also includes an oil replenishment circuit for the small oil chamber of the boost cylinder.

[0022] Wherein, the boost cylinder small oil chamber oil replenishment circuit includes a second one-way valve, and the second one-way valve is arranged in the oil circuit between the engine oil circuit and the small oil chamber.

[0023] Wherein, the first electromagnetic reversing valve and the second electromagnetic reversing valve are both two-position three-way electromagnetic reversing valves.

[0024] After adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0025] The oil-pressurized compression-release engine in-cylinder brake device of the present invention has an oil passage cavity opened in the axial direction on the camshaft, and the oil passage cavity is connected to the oil supply device through a rotating oil inlet interface device, and the oil supply device includes an oil pressurization oil circuit, and the exhaust cam on the camshaft has a mounting hole opened in the radial direction that is connected to the oil passage cavity, and a sliding plunger mechanism is arranged in the mounting hole; when the engine is in the normal working mode, the sliding plunger mechanism does not act; when the engine enters the in-cylinder brake mode, the oil pressurization oil circuit supplies oil to the oil passage cavity, and the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a brake protrusion, pushes the valve to hold or the valve cap to open the exhaust valve, and completes the in-cylinder brake. Compared with the known technology, only when the engine is in the in-cylinder brake mode, under the action of the pressurized oil, the sliding plunger mechanism extends out of the cam surface of the exhaust cam, and the working time of the sliding plunger mechanism is very short, and when the engine is in the normal working state, the sliding plunger mechanism is recovered in the mounting hole of the exhaust cam, and the entire exhaust cam is like an ordinary exhaust cam, so the reliability of the engine operation is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of an embodiment of the oil-pressurized compression-release engine cylinder brake device of the present invention;

[0027] Figure 2 yes Figure 1 A partial enlarged view of point Ⅰ in the middle;

[0028] Figure 3 yes Figure 1 Reference diagram of the working state when the sliding plunger is extended in the illustrated embodiment;

[0029] Figure 4 yes Figure 1 Sectional view at AA in the middle;

[0030] Figure 5 yes Figure 2 A schematic diagram of the structure without the camshaft part of the sliding plunger mechanism;

[0031] Figure 6 yes Figure 1 Schematic diagram of the oil supply device in;

[0032] Figure 7 yes Figure 6 Schematic diagram of the pressure reducing valve structure;

[0033] In the figure: I-valve mechanism; II-oil supply device;

[0034] 10-exhaust valve; 11-valve spring; 12-valve rocker arm; 13-rocker arm shaft; 14-push rod; 15-tappetite; 20-camshaft; 21-intake cam; 22-exhaust cam; 23-oil chamber; 24-annular oil groove; 25-timing gear; 3-rotating oil inlet interface device; 31-end cover; 32-fixed oil sleeve; 321-oil hole; 40-pressure sensor; 50-plunger booster cylinder; 51-plunger cylinder body; 511-air venting hole; 52-left end cover plate; 53-right end cover plate; 54-small-diameter plunger; 55-plunger return spring; 56-large-diameter plunger; 61-first electromagnetic reversing valve; 62-second electromagnetic reversing valve; 70-sliding plunger mechanism; 71-sliding plunger; 711 -spring mounting hole; 712-long slot hole; 72-plunger return spring; 73-pin shaft; 74-thread plug; 80-pressure reducing valve; 81-valve body; 811-oil inlet; 812-oil outlet; 82-valve ball; 83-pressure regulating spring; 84-pressure regulating screw; 91-first one-way valve; 92-second one-way valve; 100-oil pan; 101-first overflow pressure maintaining valve; 102-second overflow pressure maintaining valve; Φx-large hole; Φy-small hole; A-large oil chamber; B-small oil chamber; C-no oil chamber; L0-engine oil circuit; L1-oil boost oil circuit; L2-oil pressure reducing oil circuit; L3-camshaft oil chamber pressure relief circuit; L4-boost cylinder large oil chamber pressure relief circuit; L5-boost cylinder small oil chamber oil replenishment circuit. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0036] It should be noted that, in this article, terms such as "first" and "second" indicating order are used for descriptive purposes only and should not be understood as indicating or implying relative importance; terms such as "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection between components; it can be a direct connection between components or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0037] The core of the present invention is to equip the valve mechanism I of the engine with an oil supply device II, and to provide pressurized oil through the oil supply device II to achieve engine cylinder braking.

[0038] like Figure 1As shown, in the embodiment of the present invention, the compression release type in-cylinder brake device of the oil boosting, the valve rocker arm 12 is rotatably mounted on the rocker shaft 13, the push rod 14 and the exhaust valve 10 are respectively arranged on both sides of the rocker shaft 13, when the tappet 15 and the push rod 14 push the valve rocker arm 12 from one side to swing around the rocker shaft 13 under the action of the exhaust cam 22 of the camshaft 20, the other side of the valve rocker arm 12 presses the exhaust valve 10, and the valve is opened; when the camshaft rotates through a specified angle, the exhaust valve 10 returns to its position under the action of the valve spring 11, and the valve is closed. The camshaft 20 is synchronized with the engine crankshaft through the timing gear 25.

[0039] The above structure is the part of the engine valve mechanism used to control the exhaust valve movement. The camshaft 20 is also provided with a plurality of intake cams 21, which are used to control the opening and closing movements of the corresponding intake valves.

[0040] like Figure 1 As shown, the camshaft 20 is provided with an oil passage cavity 23 in the axial direction, and the camshaft 20 is provided with a rotary oil inlet interface device 3, which is connected to the oil supply device II, and the oil supply device II is provided with an oil boost oil circuit. The exhaust cam 22 is provided with a mounting hole in the radial direction, which is connected to the oil passage cavity 23, and a sliding plunger mechanism 70 is provided in the mounting hole. When oil is supplied to the oil passage cavity 23 through the oil boost oil circuit, the sliding plunger mechanism 70 extends out of the cam surface of the exhaust cam 22 to form a braking protrusion.

[0041] like Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the sliding plunger mechanism 70 includes a sliding plunger 71, a plunger return spring 72, a pin 73 and a screw plug 74. The mounting hole is a stepped hole, which includes a large hole Φx and a small hole Φy. The small hole Φy radially penetrates the camshaft portion on one side of the oil chamber 23 and forms a blind hole on the camshaft portion on the other side of the oil chamber 23. The large hole Φx is recessed from the oil chamber 23 to the opening direction of the small hole Φy. The pin 73 is installed in the large hole Φx. The sliding plunger 71 is installed Installed in the small hole Φy, the sliding plunger 71 is provided with a spring mounting hole 711 along the axial direction and a long slot hole 712 along the radial direction, the pin shaft 73 is slidably set in the long slot hole 712, and the plunger return spring 72 is clamped in the spring mounting hole 711 by the pin shaft 73. When the oil chamber 23 is in a pressure relief state, the plunger return spring 72 presses the sliding plunger 71 against the bottom of the blind hole, and the screw plug 74 is screwed on the outer opening end of the spring mounting hole 711 and seals the spring mounting hole 711.

[0042] During assembly, first install the sliding plunger 71 from the small hole Φy, install the plunger return spring 72 into the spring mounting hole 711, compress the plunger return spring 72, install the pin 73 into the oil chamber 23, then loosen the plunger return spring 72, and insert the pin 73 into the large hole Φx. Finally, screw the screw plug 74 to seal the spring mounting hole 711.

[0043] like Figure 1 As shown, the rotary oil inlet interface device 3 is arranged at the open end of the oil passage chamber 23, and the rotary oil inlet interface device 3 includes a fixed oil sleeve 32 and an end cover 31. The camshaft 20 is provided with an oil inlet journal, and the oil inlet journal is rotatably sealed and installed on the fixed oil sleeve 32. The outer peripheral surface of the oil inlet journal is provided with an annular oil groove 24, and the annular oil groove 24 is communicated with the oil passage chamber 23. The fixed oil sleeve 32 is provided 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 to seal the opening of the oil passage chamber 23. The end cover 31 is also provided with an annular flange for limiting the axial movement of the fixed oil sleeve 32.

[0044] Wherein, a pressure sensor 40 is provided in the oil circuit between the rotary oil inlet interface device 3 and the oil supply device II for detecting the feedback oil pressure as a basis for determination.

[0045] like Figure 6 As shown, the oil supply device II includes: an oil boost oil circuit L1, an oil decompression oil circuit L2, a camshaft oil chamber pressure relief oil circuit L3, a boost cylinder large oil chamber pressure relief oil circuit L4, and a boost cylinder small oil chamber oil replenishment oil circuit L5.

[0046] like Figure 6 As shown, the oil boosting oil circuit L1 includes: a first electromagnetic reversing valve 61, a plunger boosting cylinder 50, and a second electromagnetic reversing valve 62 connected in sequence, the first electromagnetic reversing valve 61 is connected to the engine oil circuit L0, and the second electromagnetic reversing valve 62 is connected to the rotary oil inlet interface device 3. The first electromagnetic reversing valve 61 and the second electromagnetic reversing valve 62 are preferably two-position three-way electromagnetic reversing valves.

[0047] The plunger booster cylinder 50 includes: a plunger cylinder body 51, a left end cover plate 52, a right end cover plate 53, a small-diameter plunger 54, a large-diameter plunger 56, and a plunger return spring 55. The plunger cylinder body 51 is provided with a through small-diameter hole and a large-diameter hole along its axial direction. The diameter of the large-diameter hole is D, and the diameter of the small-diameter hole is d. The design is D>>d. The two covers are fixed to the ends of the plunger cylinder body 51; the small-diameter plunger 54 is slidably installed in the small-diameter hole and is a pair of parts with the small-diameter hole. The small-diameter hole and the small-diameter plunger 54 and the left end cover plate 52 form a small oil chamber B, which is connected to the second electromagnetic reversing valve 62; the large-diameter plunger 56 is slidably installed in the large-diameter hole. The large diameter hole is a pair of parts with the large diameter hole. The large diameter hole, the large diameter plunger 56 and the right end cover plate 53 form a large oil chamber A. The large oil chamber A is connected to the first electromagnetic reversing valve 61. The plunger return spring 55 of the large diameter plunger 56 is sleeved on the small diameter plunger 54 and clamped between the bottom of the large diameter hole and the large diameter plunger 56. The chamber where the plunger return spring 55 is located is an oil-free chamber C. The plunger cylinder body 51 is provided with an air vent 511 that communicates with the oil-free chamber C. In order to reduce the difficulty of processing, the large diameter plunger 56 and the small diameter plunger 54 are designed as two independent parts. A small diameter plunger return spring can also be provided for the small diameter plunger 54 in the small oil chamber B, which is not shown in detail here. Of course, if the processing accuracy requirements can be met, the large diameter plunger 56 and the small diameter plunger 54 can also be designed as one part.

[0048] A first one-way valve 91 is provided in the oil circuit connecting the small oil chamber B and the second electromagnetic reversing valve 62 to prevent the oil in the oil chamber 23 of the camshaft 20 from flowing back into the small oil chamber B.

[0049] like Figure 6 As shown, the oil pressure reducing circuit L2 is connected in parallel with the oil pressure increasing circuit L1. The oil pressure reducing circuit includes a pressure reducing valve 80, which is arranged in the oil circuit between the second electromagnetic reversing valve 62 and the engine oil circuit L0.

[0050] like Figure 7 As shown, in this embodiment, a pressure reducing valve with a simple structure is designed. The pressure reducing valve 80 includes: a valve body 81, a valve ball 82, a pressure regulating spring 83 and a pressure regulating screw 84. The valve body 81 is provided with an oil inlet 811 and an oil outlet 812 connected to its valve cavity. The valve ball 82 and the pressure regulating spring 83 are arranged in the valve cavity. The valve ball 82 blocks the oil inlet 811. The pressure regulating screw 84 is threadedly connected to the valve body 81. One end of the pressure regulating spring 83 abuts against the valve ball 82, and the other end of the pressure regulating spring 83 abuts against the pressure regulating screw 84. By adjusting the pressure regulating screw 84, the force of the pressure regulating spring 83 on the valve ball 82 can be adjusted, thereby adjusting the pressure difference between the oil inlet 811 and the oil outlet 812.

[0051] Obviously, the pressure reducing valve 80 may also be a pressure reducing valve in the prior art.

[0052] like Figure 6 As shown, the boost cylinder large oil chamber pressure relief oil circuit L4 includes a first overflow pressure-maintaining valve 101, which is arranged in the oil circuit between the first electromagnetic reversing valve 61 and the oil pan 100. The camshaft oil chamber pressure relief oil circuit L3 includes a second overflow pressure-maintaining valve 102, which is arranged in the oil circuit between the second electromagnetic reversing valve 62 and the oil pan 100.

[0053] Among them, the structure of the overflow pressure maintaining valve is the same as that of the pressure reducing valve 80. The front end pressure is adjusted by the pressure regulating spring. The function of the first overflow pressure maintaining valve 101 is to ensure that the oil in the large oil chamber A is not drained when the large oil chamber A is depressurized, so that the next time the cylinder brakes, there is a lower opening pressure.

[0054] like Figure 6 As shown, the boost cylinder small oil chamber oil replenishing circuit L5 includes a second one-way valve 92, and the second one-way valve 92 is arranged in the oil circuit between the engine oil circuit L0 and the small oil chamber B. During the braking process in the oil boost cylinder, the oil in the engine oil circuit L0 opens the second one-way valve 92 and continuously replenishes the small oil chamber B.

[0055] The working principle of the present invention is as follows:

[0056] When the engine is working normally, that is, the engine is in the non-cylinder braking mode, the first electromagnetic reversing valve 61 and the second electromagnetic reversing valve 62 are both powered off, the oil pressure relief oil path L2 is open, and the engine oil is connected to the oil passage chamber 23 of the camshaft 20 through the pressure relief valve 80 and the second electromagnetic reversing valve 62. The thrust generated on the sliding plunger 71 of the sliding plunger mechanism 70 is less than the elastic force of the plunger return spring 72, and the sliding plunger 71 is stationary inside the camshaft 20. The pressure sensor 40 detects the oil pressure in the inner cavity of the camshaft. When the inner cavity oil pressure is greater than the starting oil pressure of the sliding plunger 71 due to a fault or other reasons, the system issues a fault alarm.

[0057] When the engine enters the in-cylinder braking mode, the first solenoid reversing valve 61 and the second solenoid reversing valve 62 are both energized, the oil boost oil circuit L1 is open, the engine oil is connected to the large oil chamber A, and the oil acts on one end of the large-diameter plunger 56. The other end of the large-diameter plunger 56 pushes the small-diameter plunger 54 to move, thereby greatly increasing the oil pressure in the small oil chamber B. After the oil pressure in the small oil chamber B is transmitted to the inner cavity of the camshaft, the thrust generated on the sliding plunger 71 is greater than the combined force of the plunger return spring 72 and the elastic force of the valve spring 11. At this time, the sliding plunger 71 moves, and its top protrudes from the cam surface of the exhaust cam 22 of the camshaft 20, pushing the tappet 15 or the valve cap to move upward, and the valve rocker arm 12 rotates around the rocker arm shaft 13 to open the exhaust valve 10 for in-cylinder braking.

[0058] During the in-cylinder braking process, the pressure sensor 40 detects the oil pressure in the camshaft cavity. When the large-diameter plunger 56 compresses the plunger return spring 55 and moves to the limit position, if the pressure sensor 40 feedback shows that the oil pressure no longer increases or begins to decrease, the first solenoid reversing valve 61 is powered off (the second solenoid reversing valve 62 is not powered off and remains powered on), and the large oil chamber A is connected to the oil pan 100 through the first overflow pressure-maintaining valve 101. The pressure drops, and the large-diameter plunger 56 moves away from the small-diameter plunger 54. After a period of time, the first solenoid reversing valve 61 is powered on again and the pressurization process is repeated until the oil pressure in the camshaft cavity reaches the requirement.

[0059] When it is required to end the in-cylinder braking, the first solenoid reversing valve 61 and the second solenoid reversing valve 62 are de-energized at the same time, the camshaft oil chamber pressure relief oil circuit L3 is open, the camshaft inner chamber oil pressure is relieved through the second overflow pressure maintaining valve 102, and the sliding plunger 71 returns to the bottom position; the boost cylinder large oil chamber pressure relief oil circuit L4 is open, the pressure in the large oil chamber A is relieved, the large diameter plunger 56 returns, and the in-cylinder braking process ends.

[0060] Compared with the known technology, the sliding plunger mechanism of the present invention only extends out of the cam surface of the exhaust cam under the action of the supercharged oil when the engine is in the in-cylinder braking mode, and the working time of the sliding plunger mechanism is very short; when the engine is in a normal working state, the oil is decompressed, and the sliding plunger mechanism is recovered in the mounting hole of the exhaust cam, and the entire exhaust cam is like an ordinary exhaust cam, so the reliability of the engine operation is higher. The present invention is applicable to both camshaft-under-mounted engines and camshaft-over-mounted engines.

[0061] The above description is an example of a preferred embodiment of the present invention, and the parts not described in detail are all known technologies of those skilled in the art. The protection scope of the present invention is based on the content of the claims, and any equivalent transformation based on the technical inspiration of the present invention is within the protection scope of the present invention.

Claims

1. An oil-pressurized compression-release type in-cylinder brake device, comprising: A camshaft, wherein the camshaft is provided with a plurality of exhaust cams; wherein: The camshaft is provided with an oil passage cavity along the axial direction, and the camshaft is provided with a rotary oil inlet interface device, the rotary oil inlet interface device is connected with an oil supply device, and the oil supply device includes an oil boost oil circuit; The exhaust cam is provided with a mounting hole in a radial direction, the mounting hole is communicated with the oil passage cavity, a sliding plunger mechanism is arranged in the mounting hole, when oil is supplied to the oil passage cavity through the engine oil boost oil passage, the sliding plunger mechanism extends out of the cam surface of the exhaust cam to form a braking protrusion; A pressure sensor is provided in the oil circuit between the rotating oil inlet interface device and the oil supply device; The oil boosting circuit comprises: a first electromagnetic reversing valve, a plunger boosting cylinder, and a second electromagnetic reversing valve connected in sequence, wherein the first electromagnetic reversing valve is connected to the engine oil circuit, and the second electromagnetic reversing valve is connected to the rotating oil inlet interface device; The plunger booster cylinder comprises: a plunger cylinder body, a cover plate, a small-diameter plunger, a large-diameter plunger, and a plunger return spring; the plunger cylinder body is provided with a through small-diameter hole and a large-diameter hole along its axial direction, and the cover plate is fixed to the end of the plunger cylinder body; the small-diameter plunger is slidably mounted in the small-diameter hole, and a small oil chamber is formed between the small-diameter hole, the small-diameter plunger, and the cover plate, and the small oil chamber is connected to the second electromagnetic reversing valve; the large-diameter plunger is slidably mounted in the large-diameter hole, and a large oil chamber is formed between the large-diameter hole, the large-diameter plunger, and the cover plate, and the large oil chamber is connected to the first electromagnetic reversing valve; the plunger return spring is sleeved on the small-diameter plunger and clamped between the bottom of the large-diameter hole and the large-diameter plunger, and the chamber where the plunger return spring is located is an oil-free chamber; The oil supply device further includes an oil pressure reducing oil circuit connected in parallel with the oil pressure increasing oil circuit; The oil pressure reducing oil circuit includes a pressure reducing valve, and the pressure reducing valve is arranged in the oil circuit between the second solenoid reversing valve and the engine oil circuit; The oil supply device also includes a pressure relief oil circuit, which includes a camshaft oil chamber pressure relief oil circuit and a booster cylinder large oil chamber pressure relief oil circuit; The boost cylinder large oil chamber pressure relief oil circuit includes a first overflow pressure-maintaining valve, which is arranged in the oil circuit between the first electromagnetic reversing valve and the oil pan; the camshaft oil chamber pressure relief oil circuit includes a second overflow pressure-maintaining valve, which is arranged in the oil circuit between the second electromagnetic reversing valve and the oil pan; The oil supply device also includes an oil supply circuit for the small oil chamber of the booster cylinder; The boost cylinder small oil chamber oil replenishment circuit includes a second one-way valve, and the second one-way valve is arranged in the oil circuit between the engine oil circuit and the small oil chamber.

2. The oil-pressurized compression-release engine in-cylinder brake device according to claim 1, characterized in that: The sliding plunger mechanism includes a sliding plunger, a plunger return spring, a pin shaft and a wire plug, the mounting hole is a stepped hole, the stepped hole includes a large hole and a small hole, the small hole radially penetrates the camshaft part on one side of the oil passage chamber and forms a blind hole on the camshaft part on the other side of the oil passage chamber, the large hole is recessed from the oil passage chamber 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, the sliding plunger is provided with a spring mounting hole in the axial direction and a long slot hole in the radial direction, 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, and when the oil passage chamber is in a pressure relief state, the plunger return spring presses the sliding plunger against the bottom of the blind hole, and the wire plug is screwed on the outer opening end of the spring mounting hole and seals the spring mounting hole.

3. The oil-pressurized compression-release engine in-cylinder brake device according to claim 1, characterized in that: The rotating oil inlet interface device is arranged at the open end of the oil passage chamber; the rotating oil inlet interface device includes a fixed oil sleeve, the camshaft is provided with an oil inlet journal, the oil inlet journal is rotatably sealed and installed on the fixed oil sleeve, an annular oil groove is provided on the outer circumference of the oil inlet journal, the annular oil groove is communicated with the oil passage chamber, the fixed oil sleeve is provided with an oil through hole, the oil through hole is communicated with the annular oil groove; the end of the camshaft is provided with an end cover for sealing the opening of the oil passage chamber.

4. The oil-pressurized compression-release engine in-cylinder brake device according to claim 1, characterized in that: The plunger cylinder body is provided with an air leakage hole communicated with the oil-free chamber.

5. The oil-pressurized compression-release engine in-cylinder brake device according to claim 1, characterized in that: A first one-way valve is arranged in the oil circuit connecting the small oil chamber and the second electromagnetic reversing valve.

6. The oil-pressurized compression-release engine in-cylinder brake device according to claim 1, characterized in that: The pressure reducing valve includes: a valve body, a valve ball, a pressure regulating spring and a pressure regulating screw. The valve body is provided with an oil inlet and an oil outlet connected with its valve cavity. The valve ball and the pressure regulating spring are arranged in the valve cavity. The valve ball blocks the oil inlet. The pressure regulating screw is threadedly connected to the valve body. One end of the pressure regulating spring abuts against the valve ball, and the other end of the pressure regulating spring abuts against the pressure regulating screw.

7. The oil-pressurized compression-release engine in-cylinder brake device according to claim 1, characterized in that: The first electromagnetic reversing valve and the second electromagnetic reversing valve are both two-position three-way electromagnetic reversing valves.

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