Brake system in engine cylinder and hydraulic control switch valve matched with brake system

Abstract

The utility model belongs to the field of engine in-cylinder braking, and discloses a hydraulic control switch valve and an engine in-cylinder braking system matched with the hydraulic control switch valve, a groove part is arranged on the peripheral surface of a valve core of the hydraulic control switch valve, and an oil drainage gap is formed between the groove part and a valve body; the engine in-cylinder braking system comprises an oil supply device connected with an engine oil path of an engine, a hydraulic control switch valve connected with the oil supply device, and a hydraulic tappet connected with the hydraulic control switch valve. When the engine is in an in-cylinder braking mode, the oil inlet and the oil outlet of the hydraulic control switch valve can still be communicated through the oil drainage gap, so that a small amount of oil is provided for the hydraulic tappet, when in-cylinder braking is started, the hydraulic tappet still has a small amount of oil supply, the small amount of oil is not enough to enable the hydraulic tappet to enter a working state, but the hydraulic tappet can be buffered, and the oil leakage is avoided. Abrasion of the hydraulic tappet is reduced, and the service life is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of engine cylinder brake, in particular to a compression release type engine cylinder brake system and a hydraulically controlled switch valve matched therewith. Background Art

[0002] In the engine valve mechanism, the hydraulic tappet can be installed on any transmission component between the cam and the valve. It is used to transmit the thrust of the camshaft to the push rod (or valve stem) and withstand the lateral force applied when the camshaft rotates. Compared with the mechanical tappet, the hydraulic tappet can automatically compensate for the valve clearance, eliminate the related components for adjusting the valve clearance, and eliminate the noise and impact caused by the valve clearance.

[0003] Among the in-cylinder braking technologies of engines, compression-release braking technology is currently the technology with the best engine braking performance. Its basic principle is: when the engine is dragged backward, during the upward movement of the piston in the compression stroke, the piston compresses the gas in the cylinder to generate braking power. Before the compression top dead center, the exhaust valve is driven to open a certain degree by the compression-release braking device to discharge the compressed high-temperature and high-pressure charge in the cylinder. At this time, the pressure in the cylinder drops rapidly. After a certain crankshaft angle, the exhaust valve is closed again, and the piston moves downward. Since the charge in the cylinder has been greatly reduced, the work done by the charge in the cylinder on the piston is also greatly reduced, reducing or eliminating the reverse braking power generated by the compressed charge in the cylinder on the piston.

[0004] Chinese invention patent application CN111535893A discloses an engine cylinder brake system and a hydraulic tappet matched therewith, and also discloses a hydraulically controlled switch valve, wherein the control oil port of the hydraulically controlled switch valve is connected to the oil supply oil circuit of the oil supply device, the oil inlet of the hydraulically controlled switch valve is connected to the engine oil circuit, and the oil outlet of the hydraulically controlled switch valve is connected to the oil inlet of the hydraulic tappet's support body. In the patent application, the hydraulically controlled switch valve is used to switch between the cylinder brake mode and the non-cylinder brake mode, and the cylinder brake system is used in conjunction with the hydraulically controlled switch valve and the hydraulic tappet, so that the engine can not only play the advantages of cylinder brake but also have the advantages of eliminating noise and impact caused by valve clearance brought by the hydraulic tappet. However, it still has the following shortcomings: when the engine is in the cylinder brake mode, the valve core of the hydraulically controlled switch valve completely blocks the oil inlet and oil outlet of the hydraulically controlled switch valve, the hydraulically controlled switch valve closes the connection between the hydraulic tappet and the external oil circuit, and the hydraulic tappet is completely cut off from oil. Although the functional requirements are met, it will cause the wear between the components of the hydraulic tappet to increase, shortening the service life of the hydraulic tappet. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the utility model provides an improved hydraulically controlled switching valve. Based on the same technical concept, the utility model also provides an engine cylinder brake system using the hydraulically controlled switching valve to increase the service life of the hydraulic tappet.

[0006] In order to solve the above technical problems related to the hydraulically controlled switch valve, the technical solution of the utility model is: a hydraulically controlled switch valve, the hydraulically controlled switch valve is a normally open valve, and the hydraulically controlled switch valve comprises:

[0007] A valve body and a valve cover fixed to the valve body, wherein the valve body is respectively provided with a control oil port, an oil inlet and an oil outlet;

[0008] A valve core disposed in the valve body and a return spring connected to the valve core, wherein the valve core is provided with a connecting hole for connecting the oil inlet and the oil outlet;

[0009] The outer peripheral surface of the valve core is provided with an annular protrusion that is slidably matched with the valve body, and a groove portion adjacent to the annular protrusion, and an oil leakage gap is formed between the groove portion and the valve body;

[0010] When the hydraulically controlled switch valve is in an open state, under the action of the return spring, the valve core blocks the control oil port, and the positions of the oil inlet, the connecting hole, and the oil outlet correspond and are connected;

[0011] When the hydraulically controlled switch valve is in a closed state, the pressure oil enters the valve body through the control oil port and pushes the valve core to detach from the control oil port. The connecting hole is staggered from the oil inlet and the oil outlet, and the oil leakage gap connects the oil inlet and the oil outlet.

[0012] In order to solve the above technical problems related to the hydraulically controlled switch valve, the technical solution of the utility model can also be: a hydraulically controlled switch valve, the hydraulically controlled switch valve is a normally open valve,

[0013] The hydraulically controlled switch valve is integrated into the rocker shaft of the engine, and the rocker shaft also serves as the valve body of the hydraulically controlled switch valve. The rocker shaft is provided with an installation cavity, a control oil circuit, an oil inlet circuit, an oil outlet circuit and a connecting oil circuit respectively communicating with the installation cavity, and the connecting oil circuit is used to connect the oil inlet circuit and the oil outlet circuit; the hydraulically controlled switch valve comprises:

[0014] A valve core and a return spring are arranged in the installation cavity, and a valve cover for closing the installation cavity, wherein the return spring is connected to the valve cover and the valve core respectively;

[0015] The outer peripheral surface of the valve core is provided with an annular protrusion that is slidably matched with the installation cavity, and a groove portion adjacent to the annular protrusion, and an oil leakage gap is formed between the groove portion and the installation cavity;

[0016] When the hydraulically controlled switch valve is in an open state, under the action of the return spring, the valve core blocks the control oil circuit, and the connecting oil circuit connects the oil inlet circuit with the oil outlet circuit;

[0017] When the hydraulically controlled switch valve is in a closed state, the pressure oil enters the installation cavity through the control oil circuit and pushes the valve core to move, and the oil leakage gap connects the oil inlet circuit with the oil outlet circuit.

[0018] In order to solve the above technical problems about the in-cylinder brake system of an engine, the technical solution of the utility model is: an in-cylinder brake system of an engine, the in-cylinder brake system of the engine comprises: an oil supply device connected to the oil circuit of the engine oil, a hydraulically controlled switch valve connected to the oil supply device, and a hydraulic tappet connected to the hydraulically controlled switch valve;

[0019] The oil supply device includes an electromagnetic reversing valve, an oil supply oil circuit and a pressure reducing oil circuit, the pressure reducing oil circuit is connected to a pressure relief oil circuit, an overflow pressure maintaining valve is arranged in the pressure relief oil circuit, and the oil supply oil circuit is selectively connected to the engine oil circuit and the pressure reducing oil circuit through the electromagnetic reversing valve;

[0020] The hydraulically controlled switching valve is the hydraulically controlled switching valve described above, the control oil port / the control oil circuit of the hydraulically controlled switching valve is connected to the oil supply circuit, the oil inlet / the oil inlet circuit of the hydraulically controlled switching valve is connected to the engine oil circuit, and the oil outlet / the oil outlet circuit of the hydraulically controlled switching valve is connected to the oil inlet of the hydraulic tappet.

[0021] After adopting the above technical solution, the utility model has achieved the following beneficial effects:

[0022] Since the outer peripheral surface of the valve core of the hydraulically controlled switching valve of the utility model is arranged to be an annular protrusion which slides with the mounting cavity of the valve body / rocker arm shaft, and a groove portion adjacent to the annular protrusion, an oil leakage gap is formed between the groove portion and the mounting cavity of the valve body / rocker arm shaft; when the engine is in the in-cylinder braking mode, although the pressure oil enters the valve body / mounting cavity through the control oil port / control oil circuit and pushes the valve core to move the hydraulically controlled switching valve, since the hydraulically controlled switching valve is provided with an oil leakage gap, its oil inlet can still be connected with the oil outlet, or the oil inlet can be connected with the oil outlet, thereby providing a small amount of oil for the hydraulic tappet. When the in-cylinder braking is started, the hydraulic tappet still has a small amount of oil to supply. The small amount of oil is not enough to put the hydraulic tappet into a working state, but it can allow the hydraulic tappet to perform buffering, reduce the wear of the hydraulic tappet, and increase its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic cross-sectional view of the structure of the hydraulically controlled switch valve in an open state according to an embodiment of the utility model;

[0024] Figure 2 yes Figure 1 Schematic diagram of the hydraulically controlled switch valve in a closed state;

[0025] Figure 3 It is a schematic cross-sectional view of the structure of the hydraulically controlled switch valve in the open state of another embodiment of the utility model;

[0026] Figure 4 yes Figure 3 Schematic diagram of the hydraulically controlled switch valve in a closed state;

[0027] Figure 5 This is a schematic diagram of the engine cylinder brake system in an unactivated state according to an embodiment of the utility model;

[0028] Figure 6 yes Figure 5 Schematic diagram of the state in the cylinder braking mode;

[0029] In the figure:

[0030] I, oil supply device; 70, throttle hole; 80, electromagnetic reversing valve; 90-check valve; 100-overflow pressure-maintaining valve; L0-engine oil circuit; La-oil supply circuit; Lb-pressure reduction circuit; Lc-pressure relief circuit;

[0031] II, hydraulically controlled on-off valve; 1101-valve body; 1102-control oil port; 1103-oil outlet; 1104-oil inlet; 1105-valve core; 1106-connecting hole; 1107-reset spring; 1108-valve cover; S-oil leakage gap;

[0032] 1100- rocker arm shaft; 1102L- control oil circuit; 1104L- oil inlet circuit; 1103L- oil outlet circuit; 1106L- connecting oil circuit;

[0033] III. Hydraulic tappet. DETAILED DESCRIPTION

[0034] It should be noted that in the description of this article, unless otherwise specified or limited, the terms "connected", "connected", "connected", etc. should be understood in a broad sense, and can be a direct connection between two elements 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 the specific circumstances.

[0035] The following is a non-limiting description of the embodiments of the present invention in further detail with reference to the accompanying drawings.

[0036] like Figure 5 and Figure 6As shown, a compression-release engine cylinder brake system is a system that uses controlled oil to achieve braking. The engine cylinder brake system includes: an oil supply device I connected to the engine oil circuit L0, a hydraulically controlled switch valve II connected to the oil supply device I, and a hydraulic tappet III connected to the hydraulically controlled switch valve II.

[0037] Among them, the oil supply device 1 includes an electromagnetic reversing valve 80, an oil supply oil circuit La and a pressure relief oil circuit Lb, the pressure relief oil circuit Lb is connected to the pressure relief oil circuit Lc, and an overflow pressure maintaining valve 100 is arranged in the pressure relief oil circuit Lc. The oil supply oil circuit La is selectively connected with the engine oil circuit L0 and the pressure relief oil circuit Lb through the electromagnetic reversing valve 80. The electromagnetic reversing valve 80 preferably adopts a two-position three-way electromagnetic reversing valve, and a check valve 90 is further arranged before the electromagnetic reversing valve 80. The check valve 90 can further protect the engine oil circuit L0 from the impact of the refluxed high-pressure oil. The pressure relief oil circuit Lc is provided with an overflow pressure maintaining valve 100. For the convenience of description, the oil pressure of the engine oil circuit L0 before decompression is defined as P1, P1 is high pressure, and the oil pressure of the engine after decompression is defined as P2, P2 is low pressure, and the set pressure of the overflow pressure maintaining valve 100 is P2 or slightly higher than P2. For more detailed structure and working principle of the engine cylinder brake system, please refer to Chinese invention patent application CN111197510A, which will not be described here.

[0038] like Figure 1 and Figure 2 As shown, a structure of a hydraulically controlled switching valve II is schematically shown. The hydraulically controlled switching valve is a normally open valve, comprising: a valve body 1101, a valve cover 1108 fixed to the valve body 1101, the valve body 1101 is respectively provided with a control oil port 1102, an oil inlet 1104 and an oil outlet 1103; a valve core 1105 and a return spring 1107 abutting against the valve core 1105 are arranged in the valve body 1101, the other end of the return spring 1107 abuts against the valve cover 1108, and the valve core 1105 is provided with a connecting hole 1106 for connecting the oil inlet 1104 and the oil outlet 1103; the outer peripheral surface of the valve core 1105 is arranged as an annular protrusion that slides with the valve body 1101, and a groove portion adjacent to the annular protrusion, and an oil leakage gap S is formed between the groove portion and the valve body.

[0039] like Figure 1 As shown, when the hydraulically controlled switch valve is in an open state, under the action of the return spring 1107, the valve core 1105 blocks the control oil port 1102, and the positions of the oil inlet 1104, the connecting hole 1106, and the oil outlet 1103 correspond and are connected.

[0040] like Figure 2As shown, when the hydraulically controlled switch valve is in a closed state, the pressure oil enters the valve body 1101 through the control oil port 1102 and pushes the valve core 1105 to disengage from the control oil port 1102. The connecting hole 1106 is staggered from the oil inlet 1104 and the oil outlet 1103, but the oil inlet 1104 and the oil outlet 1103 are connected through the oil leakage gap S.

[0041] Among them, the control oil port 1102 of the hydraulically controlled switching valve is connected to the oil supply circuit La of the oil supply device I, the oil inlet 1104 is connected to the engine oil circuit L0, and the oil outlet 1103 is connected to the oil inlet of the hydraulic tappet III.

[0042] The hydraulically controlled switch valve of the above structure is an independent valve, which can be installed at a suitable position of the engine according to actual installation requirements, and the installation is flexible and convenient.

[0043] Obviously, the hydraulic switch valve II is not limited to Figure 1 and Figure 2 The structure shown. Figure 3 and Figure 4 As shown, another structure of a hydraulically controlled switch valve is schematically shown. The hydraulically controlled switch valve is a normally open valve, which is integrated into the rocker shaft 1100 of the engine. The rocker shaft 1100 also serves as the valve body of the hydraulically controlled switch valve. An installation cavity, a control oil circuit 1102L, an oil inlet circuit 1104L, an oil outlet circuit 1103L and a connecting oil circuit 1106L which are respectively connected to the installation cavity are provided in the rocker shaft 1100. The connecting oil circuit 1106L is used to connect the oil inlet circuit 1104L and the oil outlet circuit 1103L. The hydraulically controlled switch valve includes a valve core 1105 and a return spring 1107 which are arranged in the installation cavity, and a valve cover 1108 which closes the installation cavity. The return spring 1107 is respectively in contact with the valve cover 1108 and the valve core 1105. The outer peripheral surface of the valve core 1105 is provided with an annular protrusion which is slidably matched with the installation cavity, and a groove portion which is adjacent to the annular protrusion. An oil leakage gap S is formed between the groove portion and the installation cavity.

[0044] like Figure 3 As shown, when the hydraulically controlled switch valve is in an open state, under the action of the return spring 1107, the valve core 1105 blocks the control oil circuit 1102L, and the connecting oil circuit 1106L connects the oil inlet circuit 1104L with the oil outlet circuit 1103L.

[0045] like Figure 4 As shown, when the hydraulic switch valve is in the closed state, the pressure oil enters the installation cavity of the rocker shaft 1100 through the control oil circuit 1102L and pushes the valve core 1105 to move. At this time, the oil leakage gap S can still connect the oil inlet circuit 1104L with the oil outlet circuit 1103L.

[0046] The hydraulically controlled switch valve of the above structure is integrated into the rocker shaft of the engine, does not occupy additional engine space, and has a relatively compact structure. However, it is necessary to open an oil passage and a mounting cavity in the original rocker shaft, and the structure of the rocker shaft is slightly complicated.

[0047] Among them, the control oil circuit 1102L of the hydraulically controlled switching valve is connected to the oil supply circuit La of the oil supply device I, the oil inlet circuit 1104L is connected to the engine oil circuit L0, and the oil outlet circuit 1103L is connected to the oil inlet of the hydraulic tappet body.

[0048] During the operation of the engine, when it is in the in-cylinder braking mode, Figure 6 As shown, although the high-pressure oil provided by the oil supply circuit La enters the valve body (or the rocker shaft mounting cavity) through the control oil port (or control oil circuit) and pushes the valve core to move to close the hydraulically controlled switching valve, since the hydraulically controlled switching valve is provided with an oil leakage gap S, its oil inlet and oil outlet can still be connected (or the oil inlet and oil outlet are connected) through the oil leakage gap S, thereby providing a small amount of oil for the hydraulic tappet. When the cylinder brake is started, the hydraulic tappet is still supplied with a small amount of oil. The small amount of oil is not enough to put the hydraulic tappet into a working state, but it can allow the hydraulic tappet to perform buffering, reduce the wear of the hydraulic tappet, and thus increase its service life.

[0049] 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 in the art. The protection scope of the present invention is based on the content of the claims, and any equivalent changes based on the technical inspiration of the present invention are within the protection scope of the present invention.

Claims

1. A hydraulically controlled on-off valve, the hydraulically controlled on-off valve being a normally open valve, the hydraulically controlled on-off valve comprising: A valve body and a valve cover fixed to the valve body, wherein the valve body is respectively provided with a control oil port, an oil inlet and an oil outlet; A valve core is arranged in the valve body and a return spring connected to the valve core, and the valve core is provided with a connecting hole for connecting the oil inlet and the oil outlet; characterized in that: The outer peripheral surface of the valve core is provided with an annular protrusion that is slidably matched with the valve body, and a groove portion adjacent to the annular protrusion, and an oil leakage gap is formed between the groove portion and the valve body; When the hydraulically controlled switch valve is in an open state, under the action of the return spring, the valve core blocks the control oil port, and the positions of the oil inlet, the connecting hole, and the oil outlet correspond and are connected; When the hydraulically controlled switch valve is in a closed state, the pressure oil enters the valve body through the control oil port and pushes the valve core to detach from the control oil port. The connecting hole is staggered from the oil inlet and the oil outlet, and the oil leakage gap connects the oil inlet and the oil outlet.

2. A hydraulically controlled on-off valve, the hydraulically controlled on-off valve being a normally open valve, characterized in that: The hydraulically controlled switch valve is integrated into the rocker shaft of the engine, and the rocker shaft also serves as the valve body of the hydraulically controlled switch valve. The rocker shaft is provided with an installation cavity, a control oil circuit, an oil inlet circuit, an oil outlet circuit and a connecting oil circuit respectively communicating with the installation cavity, and the connecting oil circuit is used to connect the oil inlet circuit and the oil outlet circuit; the hydraulically controlled switch valve comprises: A valve core and a return spring are arranged in the installation cavity, and a valve cover for closing the installation cavity, wherein the return spring is connected to the valve cover and the valve core respectively; The outer peripheral surface of the valve core is provided with an annular protrusion which is slidably matched with the installation cavity, and a groove portion which is adjacent to the annular protrusion, and an oil leakage gap is formed between the groove portion and the installation cavity; When the hydraulically controlled switch valve is in an open state, under the action of the return spring, the valve core blocks the control oil circuit, and the connecting oil circuit connects the oil inlet circuit with the oil outlet circuit; When the hydraulically controlled switch valve is in a closed state, the pressure oil enters the installation cavity through the control oil circuit and pushes the valve core to move, and the oil leakage gap connects the oil inlet circuit with the oil outlet circuit.

3. An engine cylinder brake system, the engine cylinder brake system comprising: An oil supply device connected to the engine oil circuit, a hydraulically controlled switch valve connected to the oil supply device, and a hydraulic tappet connected to the hydraulically controlled switch valve; The oil supply device includes an electromagnetic reversing valve, an oil supply oil circuit and a pressure reducing oil circuit, the pressure reducing oil circuit is connected to a pressure relief oil circuit, an overflow pressure maintaining valve is arranged in the pressure relief oil circuit, and the oil supply oil circuit is selectively connected to the engine oil circuit and the pressure reducing oil circuit through the electromagnetic reversing valve; it is characterized in that: The hydraulically controlled switching valve is the hydraulically controlled switching valve according to claim 1 or 2, the control oil port / the control oil circuit of the hydraulically controlled switching valve is connected to the oil supply circuit, the oil inlet / the oil inlet circuit of the hydraulically controlled switching valve is connected to the engine oil circuit, and the oil outlet / the oil outlet circuit of the hydraulically controlled switching valve is connected to the oil inlet of the hydraulic tappet.

Images