A compression release type engine cylinder brake device

Abstract

The present invention discloses a compression-release type engine cylinder brake device, comprising a driving force input camshaft, a brake rocker assembly driven by the driving force input camshaft and capable of rotating and swinging around a rocker shaft, the brake rocker assembly comprising a brake rocker and a valve clearance control mechanism arranged in a mounting hole of the brake rocker, the valve clearance control mechanism comprising a brake plunger, a return spring with an upward elastic force on the brake plunger, and a drive device with an axial downward force on the brake plunger, the brake plunger facing the exhaust valve. The driving piston of the present invention synchronously drives the upper connecting rod and the lower connecting rod to swing, because the spherical heads of the upper connecting rod and the lower connecting rod respectively perform a twisting action in the corresponding spherical groove, the upper connecting rod presses the middle slider downward during the swinging and twisting process, and then the middle slider presses the lower connecting rod, and the lower connecting rod presses the brake plunger downward, so that the brake plunger moves downward, triggering the valve cap, thereby realizing the engine cylinder braking operation.

Description

Technical Field

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

[0002] In the prior art, the method of using the engine as a braking means is well known. It is only necessary to stop the fuel supply to the engine and temporarily convert the engine from a power output to a compressor that absorbs power. When the fuel is cut off, the gas inhaled into the cylinder during the intake stroke of the engine is compressed during the compression stroke. At the end or near the end of the compression stroke of the engine piston, the exhaust valve is opened and the compressed gas is released. The energy absorbed by the engine during the compression stroke cannot be returned to the engine in the subsequent expansion stroke, but is dissipated through the exhaust system of the engine. The final result is that the engine absorbs the energy of the vehicle and slows down the speed of the vehicle.

[0003] A precedent of engine brake is disclosed in U.S. Patent No. 3,220,392 provided by Cummins. The engine brake system manufactured according to the patent is very successful in business. However, such engine brake system is installed on the cylinder head of the engine. In order to install such engine brake, the cylinder head needs to be redesigned, and the height, weight and cost of the engine are increased. The above problems are caused by treating the engine brake system as an accessory of the engine, rather than a component or integrated part of the engine.

[0004] The engine brake in current technology usually adopts a hydraulic brake mechanism. The main structure is to install a reciprocating plunger in the main piston hole on the brake rocker arm. The engine oil enters the oil chamber. Under the pressure of the engine oil, the moving plunger moves downward, so that the plunger contacts the exhaust valve cap. A one-way valve is set in the oil circuit to open the exhaust valve by utilizing the incompressibility of the engine oil.

[0005] Chinese patent publication number CN 210919173 U discloses a compression-release engine cylinder brake device, including a camshaft, wherein the camshaft is provided with a plurality of exhaust cams, and the camshaft is provided with a camshaft axial channel extending along its axial direction, and the exhaust cam is provided with an exhaust cam radial hole communicating with the camshaft axial channel along its radial direction, and a brake mechanism is provided inside the camshaft corresponding to each exhaust cam, and the brake mechanism includes a connected sliding plunger and a control shaft, the sliding plunger is slidably mounted in the exhaust cam radial hole, and the control shaft is slidably mounted in the camshaft axial channel; during cylinder braking, the brake mechanism is controlled by a driving mechanism, the control shaft slides along the camshaft axial channel and drives the sliding plunger to slide along the exhaust cam radial hole, so that the sliding plunger extends out of the cam surface of the exhaust cam to form a braking protrusion, even if the sliding plunger is pressed down by the tappet, the sliding plunger will not sink due to the support of the control shaft, the braking is reliable, and the braking effect is good; during non-cylinder braking, the brake mechanism is controlled by a reset mechanism, and the sliding plunger retracts into the exhaust cam radial hole. The technical solution of the above patent is to adopt a hydraulic brake mechanism, which has the following defects: 1. Slow response speed, with delays in opening and closing; 2. Affected by oil temperature and oil pressure, the plunger stroke changes and the oil pressure is too high when the engine speed is high, which can easily cause the hydraulic oil chamber to crack and the engine brake to be forced to close, etc., which will affect the braking performance of the vehicle. Summary of the invention

[0006] Therefore, the main purpose of the present invention is to solve the above-mentioned problems and provide a compression release type engine cylinder brake device.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is to provide a compression-release type engine cylinder brake device, including a driving force input camshaft, a brake rocker arm assembly driven by the driving force input camshaft and capable of rotating and swinging around a rocker arm shaft, the brake rocker arm assembly including a brake rocker arm and a valve clearance control mechanism arranged in a mounting hole of the brake rocker arm, the valve clearance control mechanism including a brake plunger, a return spring having an upward elastic force on the brake plunger, and a driving device having an axial downward force on the brake plunger, the brake plunger is directly opposite to the exhaust valve, when the brake plunger is at the bottom dead center and the distance between the brake plunger and the valve cap of the exhaust valve is at the minimum value, each swing of the brake rocker arm assembly causes the brake plunger to push the exhaust valve to open, and the engine cylinder brake is in a working state; when the brake plunger is at the top dead center and the distance between the brake plunger and the valve cap of the exhaust valve is at the maximum value, the brake plunger cannot touch and squeeze the exhaust valve, and the engine is in a normal working state.

[0008] The driving device includes a driving piston arranged in a slideway of a brake rocker arm, an intermediate slider movably arranged in the driving piston and movable relative to the driving piston along the axial direction of the brake plunger, a lower connecting rod arranged between the intermediate slider and the brake plunger, a power device for controlling the movement of the driving piston along the slideway, and an upper connecting rod device for controlling the movement stroke of the intermediate slider. The movement path of the driving piston intersects with the movement path of the intermediate slider. The upper end and the lower end of the lower connecting rod are movably hinged to the bottom surface of the intermediate slider and the top surface of the brake plunger respectively. Through the power device, the driving piston is moved left and right in the slideway along the axial direction, thereby changing the downward force of the lower connecting rod on the brake plunger, and then the brake plunger is moved axially.

[0009] The upper connecting rod device includes an upper connecting rod, a valve adjusting screw, a sealing gasket and a nut. The valve adjusting screw is threaded in the mounting hole. The upper end and the lower end of the upper connecting rod are respectively hinged to the bottom surface of the valve adjusting screw and the top surface of the middle sliding block. By adjusting the distance between the valve adjusting screw and the sliding block, the required height of the upper connecting rod in a vertical state when pushed by the driving piston is adjusted, and then the upper connecting rod pushes the middle sliding block downward, thereby adjusting the distance that the lower connecting rod pushes the brake plunger downward; the sealing gasket is sleeved on the valve adjusting screw and sealed to the upper end of the mounting hole, and the nut is threaded on the upper part of the valve adjusting screw and tightens and squeezes the sealing gasket.

[0010] The upper connecting rod and the lower connecting rod have the same structure and both include a rod body. Both ends of the rod body are spherical heads, and the spherical heads are respectively matched with the spherical grooves on the valve adjustment screw, the middle slider and the brake plunger.

[0011] A through hole is arranged between the spherical grooves on the top surface and the bottom surface of the middle sliding block.

[0012] The outer wall of the driving piston is provided with limiting grooves corresponding to the positions of the upper connecting rod and the lower connecting rod.

[0013] The power device includes an oil channel hole, a spring, a spring seat and a retaining spring. The oil channel hole is matched with one end of the driving piston and the oil channel hole is connected with the slideway. The high-pressure oil device injects high-pressure oil into the slideway through the oil channel hole, thereby pushing the driving piston to move along its own axis in the slideway; the spring is located at the other end of the driving piston and has an elastic force on the driving piston in the opposite direction of the oil pressure of the high-pressure oil. The spring seat has a supporting effect on the spring, and the spring seat rests on the retaining spring installed on the inner wall of the slideway.

[0014] The high-pressure oil device includes a first oil channel and a second oil channel arranged in the rocker arm shaft. The oil channel hole is connected with the second oil channel through a radial oil channel. The high-pressure oil in the first oil channel comes from the high-pressure engine oil existing during the operation of the engine. A solenoid valve is provided between the first oil channel and the second oil channel, and the solenoid valve is used to realize the connection or closure of the first oil channel and the second oil channel. The oil channel hole also passes through the pressure relief oil channel.

[0015] The inner diameter of the first oil passage is greater than the inner diameter of the second oil passage.

[0016] The driving force input camshaft includes a base circle, a first cam point and a second cam point arranged on the outer surface of the base circle, a roller is provided at one end of the braking rocker arm that matches the driving force input camshaft, and a torsion spring is provided between the braking rocker arm and the rocker arm shaft, so that the roller always fits against the outer surface of the driving force input camshaft.

[0017] The beneficial effects of the present invention are:

[0018] The compression-release type engine cylinder brake device of the present invention supplies oil to the second oil channel through the first oil channel, and then allows the high-pressure oil to enter the slideway through the radial oil channel and the oil channel hole, so that the driving piston works, and the driving piston synchronously drives the upper connecting rod and the lower connecting rod to swing. Since the spherical heads of the upper connecting rod and the lower connecting rod respectively perform twisting actions in the corresponding spherical grooves, and the upper end of the upper connecting rod is restricted by the valve adjustment screw, the upper connecting rod presses the middle slider downward during the swinging and twisting process, and then the middle slider squeezes the lower connecting rod, and the lower connecting rod squeezes the brake plunger downward, so that the brake plunger moves downward, triggering the valve cap, thereby realizing the engine cylinder braking operation. In this process, the driving piston only needs a small stroke to realize the downward movement of the brake plunger, with fast reaction speed, sensitive opening, and no delay.

[0019] The compression-release type engine cylinder brake device of the present invention utilizes an electromagnetic valve to control the clearance between the brake rocker arm and the valve cap of the exhaust valve, thereby realizing the switching and maintenance of the two states of engine cylinder braking and normal engine operation. The device can be integrated with the engine, thereby reducing the volume and weight of the engine brake, eliminating the need for a hydraulic control valve, reducing costs, and shortening the braking reaction time. There is no leakage, deformation, or load fluctuation caused by high oil pressure, and the valve clearance control mechanism is not affected by oil temperature or oil pressure, and the lift is controllable, thereby improving the braking power of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a compression-release type engine cylinder brake device of the present invention;

[0021] Figure 2 It is a structural schematic diagram of a brake plunger of a valve clearance control mechanism of a compression-release type engine cylinder brake device of the present invention being at the top dead center position;

[0022] Figure 3 It is a structural schematic diagram of a brake plunger of a compression-release type engine cylinder brake device of the present invention being at a bottom dead center position;

[0023] Figure 4 It is a structural schematic diagram of a first oil passage and a second oil passage of a high-pressure oil device of a compression-release type engine cylinder brake device of the present invention in a non-penetrating state;

[0024] Figure 5 It is a structural schematic diagram of a first oil passage and a second oil passage of a high-pressure oil device of a compression-release type engine cylinder brake device of the present invention being in a through-connected state. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0026] See also Figures 1 to 5 The present invention provides a compression-release type engine cylinder brake device, comprising a driving force input camshaft 1, a brake rocker arm assembly 3 driven by the driving force input camshaft 1 to rotate and swing around a rocker arm shaft 2, the brake rocker arm assembly 3 comprising a brake rocker arm 4 and a valve clearance control mechanism 6 arranged in a mounting hole 5 of the brake rocker arm 4, the valve clearance control mechanism 6 comprising a brake plunger 7, a return spring 8 with an upward elastic force on the brake plunger 7, and a driving device with an axial downward force on the brake plunger 7, the brake plunger 7 is directly opposite to the exhaust valve 9, when the brake plunger 7 is at the bottom dead center and the distance between the brake plunger 7 and the valve cap 10 of the exhaust valve 9 is the minimum value, each swing of the brake rocker arm assembly 3 causes the brake plunger 7 to push the exhaust valve 9 to open, and the engine cylinder brake is in a working state; when the brake plunger 7 is at the top dead center and the distance between the brake plunger 7 and the valve cap 10 of the exhaust valve 9 is the maximum value, the brake plunger 7 cannot touch and squeeze the exhaust valve 9, and the engine is in a normal working state.

[0027] The driving force input camshaft 1 comprises a base circle 11, a first cam point 12 and a second cam point 13 arranged on the outer surface of the base circle 11, a roller 14 is arranged at one end of the braking rocker arm 4 matching with the driving force input camshaft 1, a torsion spring is arranged between the braking rocker arm 4 and the rocker arm shaft 2, or a spring is used to apply elastic force to one end of the roller 14 of the braking rocker arm 4, so that the roller 14 always fits against the outer surface of the driving force input camshaft 1. When the base circle 11 of the driving force input camshaft 1 comes into contact with the roller 14, only the roller 14 rotates around its own axis, and the braking rocker arm 4 is stationary; when the first cam point 12 and the second cam point 13 on the driving force input camshaft 1 come into driving contact with the roller 14, the first cam point 12 and the second cam point 13 squeeze the braking rocker arm 4 to rotate and swing upward around the rocker arm shaft 2, so that the valve clearance control mechanism 6 at the other end of the braking rocker arm 4 moves toward the valve cap 10. In the above process, when the brake in the engine cylinder is working, the driving device causes the brake plunger 7 to move downward and reach the bottom dead center position, so that the brake plunger 7 can squeeze the valve cap 10; when the brake in the engine cylinder is not working, the driving device does not work, and the brake plunger 7 is at the top dead center position.

[0028] The driving device includes a driving piston 16 arranged in the slideway 15 of the brake rocker arm 4, an intermediate slider 17 movably arranged in the driving piston 16 and movable relative to the driving piston 16 along the axial direction of the brake plunger 7, a lower connecting rod 18 arranged between the intermediate slider 17 and the brake plunger 7, a power device 19 for controlling the movement of the driving piston 16 along the slideway 15, and an upper connecting rod device 20 for controlling the movement stroke of the intermediate slider 17. The moving path of the driving piston 16 intersects with the moving path of the intermediate slider 17. The upper end and the lower end of the lower connecting rod 18 are movably hinged to the bottom surface of the intermediate slider 17 and the top surface of the brake plunger 7 respectively. Through the power device 19, the driving piston 16 moves left and right in the slideway 15 along the axial direction, thereby changing the downward force of the lower connecting rod 18 on the brake plunger 7, and then the brake plunger 7 moves axially.

[0029] The upper connecting rod device 20 includes an upper connecting rod 21, a valve adjusting screw 22, a sealing gasket 23 and a nut 24. The valve adjusting screw 22 is screwed into the mounting hole 5. The upper end and the lower end of the upper connecting rod 21 are respectively hinged to the bottom surface of the valve adjusting screw 22 and the top surface of the intermediate slider 17. By adjusting the distance between the valve adjusting screw 22 and the intermediate slider 17, the required height of the upper connecting rod 21 in a vertical state when pushed by the driving piston 16 is adjusted, and then the upper connecting rod 21 pushes the intermediate slider 17 downward, thereby adjusting the distance that the lower connecting rod 18 pushes the brake plunger 7 downward; the sealing gasket 23 is sleeved on the valve adjusting screw 22 and sealed to the upper end of the mounting hole 5, and the nut 24 is screwed to the upper part of the valve adjusting screw 22 and tightens and squeezes the sealing gasket 23.

[0030] The upper connecting rod 21 and the lower connecting rod 18 have the same structure and both include a rod body 25 . Both ends of the rod body 25 are spherical heads 26 . The spherical heads 26 correspond to and match the spherical grooves 27 on the valve adjustment screw 22 , the middle slider 17 , and the brake plunger 7 .

[0031] The outer wall of the driving piston 16 is provided with limiting grooves 28 at positions corresponding to the upper connecting rod 21 and the lower connecting rod 18 .

[0032] A through hole 29 is provided between the spherical grooves 27 on the top and bottom surfaces of the intermediate sliding block 17 .

[0033] The power device 19 includes an oil channel hole 30, a spring 31, a spring seat 32 and a retaining spring 33. The oil channel hole 30 is matched with one end of the driving piston 16 and the oil channel hole 30 is connected with the slide 15. The high-pressure oil device 34 injects high-pressure oil into the slide 15 through the oil channel hole 30, thereby pushing the driving piston 16 to move along its own axis in the slide 15; the spring 31 is located at the other end of the driving piston 16 and has an elastic force on the driving piston 16 in the opposite direction of the oil pressure of the high-pressure oil. The spring seat 32 has a supporting effect on the spring 31, and the spring seat 32 abuts against the retaining spring 33 installed on the inner wall of the slide 15.

[0034] The installation of the driving device, the upper connecting rod device 20 and the power device 19 is as follows: a mounting hole 5 is set in the brake rocker arm 4, and the slideway 15 and the mounting hole 5 are actually cross-connected, preferably vertically connected. Through the slideway 15, we can first put in the driving piston 16, and then install the lower connecting rod 18 through the slider hole 35 on which the intermediate slider 17 is installed on the driving piston 16, and then install the intermediate slider 17 and the upper connecting rod device 20. Finally, the spring 31 and the spring seat 32 are installed in the slideway 15 in turn, and the retaining spring 33 is inserted into the retaining spring groove 36 on the inner wall of the slideway 15, so that the spring 31 has a rightward elastic force on the driving piston 16, and the driving piston 16 is always in the right dead center position, the oil channel hole 30 is on the right side of the slideway 15, and the high-pressure oil has a leftward driving force on the driving piston 16. When the driving force is greater than the superimposed elastic force of the spring 31 and the reset spring 8 at the lower end of the brake plunger 7, the driving piston 16 moves to the left.

[0035] The high-pressure oil device 34 includes a first oil passage 37 and a second oil passage 38 arranged in the rocker shaft 2. The oil passage hole 30 is connected with the second oil passage 38 through a radial oil passage 39. The high-pressure oil in the first oil passage 37 comes from the high-pressure engine oil existing during the operation of the engine. A solenoid valve 40 is provided between the first oil passage 37 and the second oil passage 38. The solenoid valve 40 is fixed on the rocker shaft seat 49. Through the solenoid valve 40, the first oil passage 37 and the second oil passage 38 are connected or closed. The oil passage hole 30 also passes through the pressure relief oil passage 41.

[0036] The inner diameter of the first oil passage 37 is greater than the inner diameter of the second oil passage 38 .

[0037] In the present invention, the driving force input camshaft 1 is also provided with an exhaust cam point 42, such as Figure 1 In the right part shown, the exhaust rocker arm 43 is hinged on the rocker shaft 2, and one end of the exhaust rocker arm 43 is provided with a roller 44, which abuts against the outer surface of the driving force input camshaft 1, and the other end of the exhaust rocker arm 43 is connected to the valve bridge 45, and the valve bridge 45 is connected to the rod body 25 of the exhaust valve 9, and the exhaust valve 9 is located in the engine cylinder head 46. A valve spring 47 is provided between the valve bridge 45 and the cylinder head 46. In the above technical solution, the rocker shaft 2 and the driving force input camshaft 1 involved in the exhaust rocker arm 43 are the rocker shaft 2 and the driving force input camshaft 1 involved in the brake rocker arm 4. In order to make the drawing more clear, Figure 1 The exhaust rocker arm 43 and the brake rocker arm 4 are shown separately on both sides of the cylinder head 46. When the engine is working normally, the exhaust valve 9 and the valve spring 47 arranged between the cylinder head 46 and the valve bridge 507 are linked with the valve bridge 45. When the roller of the exhaust rocker arm 43 contacts the exhaust cam point 42 section of the driving force input camshaft 1, the other end of the exhaust rocker arm moves downward, the valve bridge 45 is subjected to pressure, overcomes the spring force of the valve spring 47, opens the exhaust valve, and releases the exhaust gas generated by the engine combustion. When the roller of the exhaust rocker arm 43 contacts the base circle 11 section of the driving force input camshaft 1, the exhaust valve 9 resumes the sealing state with the cylinder head 46.

[0038] The working principle of the compression release type engine cylinder brake device of the present invention is described below:

[0039] The compression release type engine cylinder brake device of the present invention needs to switch the engine from the normal working state to the engine cylinder brake working state, and send an action signal to the solenoid valve 40 through the engine ECU controller and open the power supply for the solenoid valve 40. When the current at the positive and negative terminals of the solenoid valve 40 is turned on, the valve core 48 of the solenoid valve 40 slides upward under the action of magnetic force, so that the first oil channel 37 and the second oil channel 38 are connected, so that the high-pressure engine oil flows to the valve clearance control mechanism 6 through the second oil channel 38, the radial oil channel 39 and the oil channel hole 30, that is, the high-pressure engine oil enters the right side of the slide 15, and the high-pressure engine oil overcomes the elastic force of the spring 31 at the left end of the driving piston 16 and the superimposed elastic force of the return spring 8 at the lower end of the brake plunger 7, and pushes the driving piston 16 to the left and stops on the spring seat 32. At this time, the upper connecting rod 21, the middle slider 17, and the lower connecting rod 1 8 and the brake plunger 7 are in a colinear vertical state, that is, the driving piston 16 moves to the left, driving the lower end and upper end of the upper connecting rod 21 and the lower connecting rod 18 to move from right to left. In this process, since the distance between the top surface of the brake plunger 7 and the bottom surface of the middle slider 17 is less than the length of the lower connecting rod 18, the distance from the bottom surface of the valve adjusting screw 22 to the top surface of the middle slider 17 is less than or equal to the length of the upper connecting rod 21, driven by the driving piston 16, the lower connecting rod 18 squeezes the brake plunger 7 downward and moves the brake plunger 7 downward, while the upper connecting rod 21 squeezes or does not squeeze the middle slider 17 to move downward. When the brake plunger 7 moves downward, the size of the displacement depends on the distance between the top surface of the brake plunger 7 and the bottom surface of the middle slider 17. To adjust this distance, we only need to loosen the nut 24 and rotate the valve adjusting screw 22 to adjust it. After the adjustment is completed, tighten the nut 24. In the above process, the upper connecting rod 21 and the lower connecting rod 18 are switched from an inclined state to a vertical state, so that the brake plunger 7 is extended to the operating position, and the gap between the brake plunger 7 and the valve cap 10 of the exhaust valve 9 is eliminated or reduced. The driving force is input to the camshaft 1, which is connected to the transmission mechanism of the engine and rotates with the engine. The driving force is input to the first cam point 12 and the second cam point 13 of the camshaft 1, so that the brake rocker arm 4 swings up and down with the rocker shaft 2 as the center. The brake plunger 7 on the brake rocker arm 4 applies pressure to the valve cap 10 of the exhaust valve 9. The pressure on the valve cap 10 is transmitted to the exhaust valve 9, and the exhaust valve 9 overcomes the elastic force of the valve spring 47, opens the exhaust valve 9 and releases the compressed air.When the engine cylinder braking is not needed, the engine ECU controller cuts off the power supply of the solenoid valve 40, and the solenoid valve 40 does not generate magnetic force. Under the action of the spring force of the solenoid valve 40, the valve core 48 moves downward, and the valve core 48 cuts off the oil path between the first oil channel 37 and the second oil channel 38. The oil channel hole 30 is penetrated by a pressure relief oil channel 41, and the pressure relief oil channel 41 is the gap between the brake rocker arm 4 and the rocker arm shaft 2, so that the high-pressure oil is depressurized, and the driving piston 16 moves to the right under the elastic force of the spring 31, and the brake plunger 7 moves upward under the action of the return spring 8, so that the brake plunger 7 retracts to the non-operating position, that is, the "off" position of the engine cylinder braking, and is separated from the normal operation of the engine.

[0040] The compression-release type engine in-cylinder brake device provided by the embodiment of the present invention is introduced in detail above. Specific examples are used herein to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the technical solutions disclosed by the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation modes and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A compression release type engine cylinder brake device, characterized in that: The invention comprises a driving force input camshaft, a brake rocker arm assembly which is driven by the driving force input camshaft and can rotate and swing around a rocker arm shaft, the brake rocker arm assembly comprises a brake rocker arm and a valve clearance control mechanism arranged in a mounting hole of the brake rocker arm, the valve clearance control mechanism comprises a brake plunger, a return spring with an upward elastic force on the brake plunger, and a driving device with an axial downward force on the brake plunger, the brake plunger is directly opposite to the exhaust valve, when the brake plunger is at the bottom dead point and the distance between the brake plunger and the valve cap of the exhaust valve is at the minimum, each swing of the brake rocker arm assembly causes the brake plunger to push the exhaust valve to open, and the brake in the engine cylinder is in working The brake piston is in the upper working state; when the brake plunger is at the top dead center and the distance between the brake plunger and the valve cap of the exhaust valve is at the maximum value, the brake plunger cannot touch and squeeze the exhaust valve, and the engine is in a normal working state; the driving device comprises a driving piston arranged in the slideway of the brake rocker arm, an intermediate slider movably arranged in the driving piston and capable of moving relative to the driving piston along the axial direction of the brake plunger, a lower connecting rod arranged between the intermediate slider and the brake plunger, a power device for controlling the movement of the driving piston along the slideway, and an upper connecting rod device for controlling the movement stroke of the intermediate slider, the moving path of the driving piston intersects with the moving path of the intermediate slider, and the upper and lower ends of the lower connecting rod are respectively The upper connecting rod device comprises an upper connecting rod, a valve adjusting screw, a sealing gasket and a nut. The valve adjusting screw is screwed in the mounting hole. The upper end and the lower end of the upper connecting rod are respectively hinged with the bottom surface of the valve adjusting screw and the top surface of the middle sliding block. By adjusting the distance between the valve adjusting screw and the sliding block, the required height of the upper connecting rod in a vertical state when pushed by the driving piston is adjusted, so that the upper connecting rod pushes the middle The slider moves downward, thereby adjusting the distance that the lower connecting rod pushes the brake plunger downward; the sealing gasket is sleeved on the valve adjusting screw and sealed to the upper end of the mounting hole, and the nut is threaded on the upper part of the valve adjusting screw and tightens and squeezes the sealing gasket; the outer wall of the driving piston is respectively provided with limit grooves corresponding to the positions of the upper connecting rod and the lower connecting rod; the driving force input camshaft includes a base circle, a first cam point and a second cam point arranged on the outer surface of the base circle, a roller is provided at one end of the braking rocker arm that matches the driving force input camshaft, and a torsion spring is provided between the braking rocker arm and the rocker arm shaft, so that the roller is always in contact with the outer surface of the driving force input camshaft.

2. The compression-release type engine in-cylinder brake device according to claim 1, characterized in that: The upper connecting rod and the lower connecting rod have the same structure and both include a rod body. Both ends of the rod body are spherical heads, and the spherical heads are respectively matched with the spherical grooves on the valve adjustment screw, the middle slider and the brake plunger.

3. The compression release type engine cylinder brake device according to claim 1 or 2, characterized in that: A through hole is arranged between the spherical grooves on the top surface and the bottom surface of the middle sliding block.

4. The compression-release type engine in-cylinder brake device according to claim 1, characterized in that: The power device includes an oil channel hole, a spring, a spring seat and a retaining spring. The oil channel hole is matched with one end of the driving piston and the oil channel hole is connected with the slideway. The high-pressure oil device injects high-pressure oil into the slideway through the oil channel hole, thereby pushing the driving piston to move along its own axis in the slideway; the spring is located at the other end of the driving piston and has an elastic force on the driving piston in the opposite direction of the oil pressure of the high-pressure oil. The spring seat has a supporting effect on the spring, and the spring seat rests on the retaining spring installed on the inner wall of the slideway.

5. The compression-release type engine in-cylinder brake device according to claim 4, characterized in that: The high-pressure oil device includes a first oil channel and a second oil channel arranged in the rocker arm shaft. The oil channel hole is connected with the second oil channel through a radial oil channel. The high-pressure oil in the first oil channel comes from the high-pressure engine oil existing during the operation of the engine. A solenoid valve is provided between the first oil channel and the second oil channel, and the solenoid valve is used to realize the connection or closure of the first oil channel and the second oil channel. The oil channel hole also passes through the pressure relief oil channel.

6. The compression-release type engine in-cylinder brake device according to claim 5, characterized in that: The inner diameter of the first oil passage is greater than the inner diameter of the second oil passage.

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