Engine valve timing measurement device and measurement method

Abstract

The present application relates to the technical field of engine valve timing measurement, and discloses an engine valve timing measurement device, which comprises a driving mechanism and a measuring mechanism; the driving mechanism comprises a motor and a shaft coupling, the motor comprises an encoder, the output shaft of the motor is connected with the shaft coupling, and the shaft coupling is used for being connected with a crankshaft of an engine; the measuring mechanism comprises a base, a first displacement measuring device, a second displacement measuring device and a tappet component, and the first displacement measuring device is arranged on the base. The present application also discloses an engine valve timing measurement method, which comprises reading a first rotation angle alpha1 of the crankshaft when a piston actual top dead center is read by the encoder and a second rotation angle alpha2 of the crankshaft when a tappet lift is h, calculating a clamping angle beta of the crankshaft through the first rotation angle alpha1 and the second rotation angle alpha2, obtaining a rotation angle gamma of the crankshaft from a starting point of a valve lift m to a moving starting point of the tappet to the tappet lift h, and calculating a valve timing delta = beta-gamma. The present application does not need to replace the hydraulic tappet.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine valve timing measurement, and particularly relates to an engine valve timing measurement device and a measurement method. BACKGROUND

[0002] At present, engine valve timing refers to the crankshaft compression top dead center as zero, and the valve opening time and the valve closing time correspond to the crankshaft angle, and the valve opening time and the valve closing time are generally judged by using the position of the valve lift of 1mm. The engine valve timing precision has a great influence on the engine performance and fuel consumption, especially for the Miller cycle engine, so the measurement of the engine valve timing is particularly important.

[0003] For the valve drive mechanism of the roller rocker arm plus the hydraulic lifter, the valve timing is obtained by measuring the valve lift, and since the hydraulic lifter is compressed under force during the measurement, the high pressure chamber cannot be formed to bear the pressure when the cam presses the roller rocker arm, so the actual valve lift cannot be measured.

[0004] At present, a rigid lifter is used to replace the hydraulic lifter during the phase measurement, the rigid lifter is a rigid cylinder, and the crankshaft angle is output through a scale disc. During the measurement, the crankshaft is rotated, and then the cam is driven to rotate through the timing chain, the rigid lifter does not move when the cam rotates, the rocker arm swings and drives the valve to move, and the displacement of the valve is measured through the micrometer. The crankshaft angle is read through the scale disc, and the hydraulic lifter needs to be replaced after the measurement is completed, so the timing system and the camshaft need to be disassembled and reassembled, which affects the assembly progress and the measurement result of the valve timing.

[0005] The existing measurement of the engine valve timing has the following defects:

[0006] 1. The crankshaft angle is read by the scale disc, and the efficiency and accuracy are poor;

[0007] 2. The rigid lifter used in the measurement process cannot be used for engine operation, and the rigid lifter needs to be disassembled and replaced after the measurement is completed, which affects the assembly efficiency;

[0008] 3. During the measurement of the valve lift, the angle of the digital micrometer needs to be adjusted to be parallel to the direction of the valve, and the measurement efficiency is low;

[0009] 4. The hydraulic tensioner is used to adjust the tensioning degree of the timing chain, and the tensioner is not supplied with oil during the measurement process, and the camshaft will rebound when the hydraulic tensioner is compressed during the rotation of the crankshaft, which affects the measurement result. SUMMARY

[0010] The purpose of the present application is to overcome the defects of the prior art, and to provide a valve timing measurement device and method which are convenient to operate, high in measurement efficiency and do not need to replace the hydraulic lifter.

[0011] In order to achieve the above object, the application provides an engine valve timing measurement device, comprising a driving mechanism and a measurement mechanism.

[0012] The driving mechanism comprises a motor and a shaft coupling, the motor comprises an encoder, and the output shaft of the motor is connected with the shaft coupling, and the shaft coupling is used for connecting with the crankshaft of the engine.

[0013] The measurement mechanism comprises a base, a first displacement measurement device, a second displacement measurement device and a tappet component, the first displacement measurement device is arranged on the base.

[0014] The tappet component comprises a hollow tappet support, an elastic member arranged in the tappet support and a tappet, the bottom of the tappet support is provided with a first mounting hole used for fixedly connecting with the engine, and the top of the tappet support is provided with a measurement hole through which the first displacement measurement device passes.

[0015] The tappet is movably arranged in the lower part of the tappet support, and the lower part of the tappet is provided with a protruding part used for cooperating with the cam of the engine.

[0016] The elastic member is located above the tappet, and the two ends of the elastic member abut against the tappet and the tappet support respectively.

[0017] As a preferred scheme, a manual tensioner is further included, the manual tensioner comprises a tensioning bolt and a tensioning seat, the tensioning seat is provided with a threaded hole and a second mounting hole used for fixedly connecting with the engine, the threaded hole penetrates through the tensioning seat, and in the working state, the tensioning bolt is pressed against the timing chain guide rail of the engine through the threaded hole.

[0018] As a preferred scheme, the tappet comprises a roller and a shell, the shell is connected to the inside of the tappet support through an anti-rotation structure, the inside of the shell is provided with a cavity penetrating through the upper and lower surfaces of the shell, and the middle of the cavity is provided with a partition plate to divide the cavity into an upper chamber and a lower chamber, the lower end of the elastic member is connected to the upper chamber, and the roller is rotatably connected to the lower chamber and protrudes from the lower part of the shell to form the protruding part.

[0019] As a preferred scheme, the anti-rotation structure comprises a positioning pin arranged on the outer side surface of the shell and a positioning groove opened on the inner side surface of the tappet support, the positioning pin is inserted into the positioning groove and can move up and down along the positioning groove to prevent the tappet from rotating with the tappet support during the up and down movement of the tappet.

[0020] As a preferred scheme, the base comprises a magnetic base and a support arm, one end of the support arm is detachably connected to the magnetic base, and the first displacement measurement device is detachably connected to the other end of the support arm.

[0021] As a preferred solution, the first displacement measuring device and the second displacement measuring device are both dial gauges, the elastic member is a spring, the motor is a servo motor, and the coupling is a flexible coupling.

[0022] The application also provides an engine valve timing measurement method, which is realized by using the engine valve timing measurement device, and comprises the following steps:

[0023] The tappet member is installed on the engine cylinder head, and the protruding part of the tappet is abutted against the upper end of the cam, the first displacement measuring device is abutted against the tappet through the measuring hole, and the second displacement measuring device is abutted against the engine piston.

[0024] The crankshaft of the engine is driven to rotate, the timing chain is driven to rotate by the crankshaft, the cam is driven to rotate by the timing chain, and the piston is driven to move up and down with the rotation of the crankshaft.

[0025] When the second displacement measuring device measures the displacement of the actual top dead center of the piston as y1, the first rotation angle α1 of the crankshaft is read by the encoder.

[0026] The valve lift corresponding to the valve opening time or the valve closing time is recorded as m, the abscissa point corresponding to the valve lift m is read according to the valve lift curve and the tappet lift curve, the tappet lift corresponding to the abscissa point is determined, and the tappet lift at this time is recorded as h.

[0027] When the first displacement measuring device measures the tappet lift as h, the second rotation angle α2 of the crankshaft is read by the encoder.

[0028] The included angle β between the state of the crankshaft at the top dead center of the piston and the state of the tappet lift h is calculated by the first rotation angle α1 and the second rotation angle α2, wherein β = α2 - α1.

[0029] The rotation angle γ of the crankshaft from the starting point of the valve lift m to the starting point of the movement of the tappet to the tappet lift h is obtained, and the engine valve timing δ is calculated by β and γ, wherein δ = β - γ.

[0030] As a preferred solution, the actual top dead center of the piston is obtained by the following steps:

[0031] The top dead center of the piston is measured by the second displacement measuring device, and the top dead center is corrected to obtain the actual top dead center of the piston.

[0032] As a preferred solution, the correction method of the actual top dead center of the piston comprises the following steps:

[0033] The displacement y of the piston is measured by the second displacement measuring device, and the rotation angle x of the crankshaft corresponding to the piston displacement y is read by the encoder, and the coordinates (x1, y1) of the piston top dead center are obtained, and the previous point (x2, y2) and the next point (x3, y3) of the piston top dead center are taken;

[0034] The horizontal coordinate x0 corresponding to the actual top dead center is corrected by the following model:

[0035] x0 = x2 + 0.5 × a × (4 × y1 - 3 × y2 - y3) / (2 × y1 - y2 - y3);

[0036] The displacement y0 of the piston when the rotation angle of the crankshaft is x0 is obtained;

[0037] The coordinates (x0, y0) of the actual top dead center of the piston are obtained;

[0038] Wherein, a represents the step length, x0 represents the crankshaft rotation angle of the corrected actual top dead center, y0 represents the piston displacement of the corrected actual top dead center, x1, x2 and x3 represent the crankshaft rotation angles corresponding to the encoder outputs of the three points, and y1, y2 and y3 represent the piston displacements corresponding to the second displacement measuring device outputs of the three points.

[0039] As a preferred solution, the step of obtaining the rotation angle γ of the crankshaft from the starting point of the valve lift m to the moving starting point of the lifter to the lifter lift h includes:

[0040] The rotation angle C of the cam from the starting point of the valve lift m to the moving starting point of the lifter to the lifter lift h is obtained;

[0041] The rotation angle γ of the crankshaft from the starting point of the valve lift m to the moving starting point of the lifter to the lifter lift h is calculated according to the rotation angle C, wherein γ = 2 × C.

[0042] As a preferred solution, the following steps are further included before driving the rotation of the crankshaft of the engine:

[0043] The tensioning state of the timing chain is manually adjusted by the tensioning bolt.

[0044] As a preferred solution, the valve lift m corresponding to the valve opening time or the valve closing time is 1 mm.

[0045] The present application has the following advantages:

[0046] 1. The engine valve timing measuring device of the present application, the motor is connected with the crankshaft through the shaft coupling, and the motor comprises an encoder, the crankshaft angle can be read through the encoder; the valve timing of the engine is measured through the tappet component, the first displacement measuring device and the second displacement measuring device, the tappet in the tappet component moves up and down in the tappet support, the valve lift of opening or closing the valve is converted into the lift of the tappet, the lift of the tappet is measured through the first displacement measuring device, and the displacement of the piston is measured by the second displacement measuring device, so that the top dead center of the piston is determined, the tappet component of the embodiment is fixed outside the engine, the hydraulic tappet inside the engine does not need to be replaced, and the first displacement measuring device does not need to be adjusted to be parallel to the valve direction in the measuring process, so that the operation is convenient, and the measuring efficiency is high.

[0047] 2. The engine valve timing measuring method of the present application, the data of the first displacement measuring device, the second displacement measuring device and the encoder are read, the measurement values of the tappet lift, the piston displacement and the crankshaft angle are obtained, the top dead center of the piston is obtained from the piston displacement measurement value, the tappet lift corresponding to the valve lift of opening or closing the valve is read from the valve lift curve and the tappet lift curve diagram of the valve timing mechanism, the crankshaft angle corresponding to the top dead center of the piston and the tappet lift is obtained through the encoder, the crankshaft angle corresponding to the top dead center of the piston and the tappet lift is calculated, and the phase value is calculated according to the valve timing calculation formula of the measuring method. The crankshaft angle is read from the encoder, the measuring accuracy is improved, the valve lift is converted into the lift of the tappet to calculate the valve timing, the tappet component of the embodiment is fixed outside the engine, the hydraulic tappet inside the engine does not need to be replaced, the operation is convenient, and the measuring efficiency is high. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 It is the overall structure schematic diagram of the embodiment of the present application;

[0049] Figure 2 It is the driving mechanism structure schematic diagram of the embodiment of the present application;

[0050] Figure 3 It is the measuring mechanism installation structure schematic diagram of the embodiment of the present application;

[0051] Figure 4 It is the tappet support structure schematic diagram of the embodiment of the present application;

[0052] Figure 5 It is the internal structure schematic diagram of the tappet of the embodiment of the present application;

[0053] Figure 6 It is the tappet structure schematic diagram of the embodiment of the present application;

[0054] Figure 7 It is the valve lift curve and the tappet lift curve diagram of the embodiment of the present application.

[0055] In the drawings:

[0056] 1. drive mechanism; 11. motor; 12. coupling; 2. measuring mechanism; 21. base; 21a. magnetic table seat; 21b. support arm; 22. first displacement measuring device; 23. second displacement measuring device; 24. tappet member; 241. tappet support; 241a. measuring hole; 241b. positioning groove; 241c. first mounting hole; 242. elastic member; 243. tappet; 243-1. housing; 243-1a. upper chamber; 243-1b. partition; 243-1c. lower chamber; 243-2. positioning pin; 243-3. roller; 3. crankshaft; 4. timing chain; 5. valve; 6. piston; 7. manual tensioner; 7a. tensioning bolt; 7b. tensioning seat; 7c. second mounting hole; 8. timing chain guide rail; 9. cam. DETAILED DESCRIPTION

[0057] The specific embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0058] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer" and the like in the present application are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application; the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0059] As Figures 1 to 3 shown, the engine valve timing measuring device of the preferred embodiment of the present application comprises a drive mechanism and a measuring mechanism;

[0060] The drive mechanism 1 comprises a motor 11 and a coupling 12, the motor 11 comprises an encoder, the output shaft of the motor 11 is connected with the coupling 12, and the coupling 12 is used to be connected with the crankshaft 3 of the engine; in operation, the motor 11 drives the crankshaft 3, and at the same time, the encoder records the rotation angle of the crankshaft 3, and then the rotation of the cam 9 of the engine is driven through the timing chain 4 of the engine, so as to drive the opening or closing of the valve 5 of the engine, and the piston 6 of the engine moves up and down with the rotation of the crankshaft 3. The rotation angle of the crankshaft 3 is recorded by the encoder, which improves the efficiency and accuracy compared with reading the rotation angle of the crankshaft 3 by the scale disc.

[0061] The measuring mechanism 2 comprises a base 21, a first displacement measuring device 22, a second displacement measuring device 23 and a tappet member 24, the first displacement measuring device 22 is arranged on the base 21; the first displacement measuring device 22 is used for measuring the lift of a tappet 243 in the tappet member 24, and the second displacement measuring device 23 is used for measuring the displacement of the piston 6 of the engine.

[0062] The tappet member comprises a hollow tappet support 241, an elastic member 242 arranged inside the tappet support 241 and a tappet 243, the bottom of the tappet support 241 is provided with a first mounting hole 241c for fixed connection with the engine, and the top of the tappet support 241 is provided with a measuring hole 241a through which the first displacement measuring device 22 passes; the tappet 243 is movably arranged in the lower part of the tappet support 241, and the lower part of the tappet 243 is provided with a protruding part for cooperating with the cam 9 of the engine; the elastic member 242 is located above the tappet 243, and the two ends thereof abut against the tappet 243 and the tappet support 241 respectively. In working, with the rotation of the cam 9, the tappet 243 moves up and down in the tappet support 241, the first displacement measuring device 22 passes through the measuring hole 241a of the tappet support 241 and abuts against the tappet 243, so as to measure the lift of the tappet 243, and the elastic member 242 makes the tappet 243 better contact with the cam 9.

[0063] Further, as shown in Figure 1 , the manual tensioner 7 comprises a tensioning bolt 7a and a tensioning seat 7b, the tensioning seat is provided with a threaded hole and a second mounting hole 7c for fixed connection with the engine, the threaded hole penetrates through the tensioning seat 7b, and in the working state, the tensioning bolt 7a is pressed against the timing chain guide 8 of the engine through the threaded hole. The tensioning bolt 7a presses the timing chain guide 8, so that the timing chain 4 is in a tensioned state, which can prevent the timing chain 4 from loosening and causing the cam 9 to rebound, thereby affecting the measurement accuracy.

[0064] Further, as shown in Figure 5 and Figure 6As shown in the figure, the tappet 243 comprises a roller 243-3 and a housing 243-1, the housing 243-1 is connected to the inside of the tappet support 241 by an anti-rotation structure, the inside of the housing 243-1 is provided with a cavity penetrating through its upper and lower surfaces, and the middle of the cavity is provided with a partition plate 243-1b to divide it into an upper chamber 243-1a and a lower chamber 243-1c, the lower end of the elastic member 242 is connected in the upper chamber 243-1a, and the roller 243-3 is rotatably connected to the lower chamber 243-1c and protrudes from the lower part of the housing 243-1 to form the protruding part. The protruding part is matched with the cam 9 by the roller 243-3, and the elastic member 242 is connected in the upper chamber 243-1a of the tappet 243, which can better make the tappet 243 contact with the cam 9 under the action of gravity.

[0065] Further, as shown in the figure, Figures 4 to 6 The anti-rotation structure comprises a positioning pin 243-2 provided on the outer side surface of the housing 243-1 and a positioning groove 241b opened on the inner side surface of the tappet support 241, the positioning pin 243-2 is inserted into the positioning groove 241b and can move up and down along the positioning groove 241b to prevent the tappet 243 from rotating with the tappet support 241 during the up and down movement. Through the anti-rotation structure, the axis of the roller 243-3 is parallel to the axis of the cam 9.

[0066] In addition, the positioning groove 241b can be provided as a positioning pin hole matched with the positioning pin 243-2 to prevent the tappet 243 from rotating.

[0067] Further, as shown in the figure, Figure 1 And Figure 3 The base comprises a magnetic table seat 21a and a support arm 21b, one end of the support arm 21b is detachably connected to the magnetic table seat 21a, and the first displacement measuring device 22 is detachably connected to the other end of the support arm 21b. The magnetic table seat 21a is installed on the engine cylinder head, by loosening the connecting part of the support arm 21b and the magnetic table seat 21a, the position of the support arm 21b can be adjusted, so that the measuring end of the first displacement measuring device 22 is just abutted on the tappet 243; by loosening the connecting part of the support arm 21b and the first displacement measuring device 22, the first displacement measuring device 22 can be adjusted to be vertically abutted on the tappet 243, that is, parallel to the tappet 243.

[0068] Further, the first displacement measuring device 22 and the second displacement measuring device 23 are both micrometers, the elastic member 242 is a spring, the motor 11 is a servo motor, and the coupling 12 is a flexible coupling. Preferably, the micrometer is a digital micrometer, which has higher precision than a scale table read by a human and can be read by a computer. In addition, the first displacement measuring device 22 and the second displacement measuring device 23 can also be digital micrometers. The flexible coupling connects the motor 11 and the crankshaft 3, and no centering is required, which improves installation efficiency.

[0069] An engine valve timing measurement method according to an embodiment of the present application is implemented by using the engine valve timing measurement device described above, and includes the following steps.

[0070] First, the tappet member 24 is installed on the engine cylinder head, the protruding portion of the tappet 243 abuts against the upper end of the cam 9, the first displacement measuring device 22 abuts against the tappet 243 through the measuring hole 241a, and specifically, the head of a micrometer abuts against the tappet 243 through the measuring hole 241a, and the second displacement measuring device 23 abuts against the piston 6 of the engine, and specifically, the head of another micrometer abuts against the piston 6 of the engine.

[0071] Second, the tension of the timing chain 4 is manually adjusted by the tensioning bolt 7a, the crankshaft 3 of the engine is driven to rotate, the timing chain 4 is driven to rotate by the crankshaft 3, the cam 9 is driven to rotate by the timing chain 4, and the piston 6 is driven to move up and down by the rotation of the crankshaft 3.

[0072] Third, the top dead center of the piston 6 is measured by the second displacement measuring device 23, and the top dead center of the piston 6 is corrected to obtain the coordinates (x0, y0) of the actual top dead center of the piston 6, wherein, in the coordinate system, x represents the rotation angle of the crankshaft 3, and y represents the displacement of the piston 6. When the second displacement measuring device 23 measures the displacement y1 of the actual top dead center of the piston 6, the first rotation angle α1 of the crankshaft 3 is read by the encoder.

[0073] Specifically, the correction method of the actual top dead center of the piston 6 includes the following steps.

[0074] The displacement y of the piston 6 is measured by the second displacement measuring device 23, the rotation angle x of the crankshaft 3 corresponding to the displacement y of the piston 6 is read by the encoder at the same time, the coordinates (x1, y1) of the top dead center of the piston 6 are obtained, and the previous point (x2, y2) and the next point (x3, y3) of the top dead center of the piston 6 are obtained, wherein the previous point refers to any point before the top dead center of the piston 6 in the movement process of the piston 6, and the next point refers to any point after the top dead center of the piston 6 in the movement process of the piston 6.

[0075] The actual top dead center is corrected by the following model:

[0076] x0=x2+0.5×a×(4×y1-3×y2-y3) / (2×y1-y2-y3);

[0077] The displacement y0 of the piston at the crankshaft rotation angle x0 is obtained;

[0078] The coordinates of the actual top dead center of the piston are (x0, y0);

[0079] Wherein a represents a step size, x0 represents the crankshaft rotation angle of the corrected actual top dead center, y0 represents the piston displacement of the corrected actual top dead center, x1, x2 and x3 represent the crankshaft rotation angles corresponding to the encoder outputs of the three points, and y1, y2 and y3 represent the piston displacements output by the second displacement measuring device 23 corresponding to the three points.

[0080] The measured piston top dead center has an error, and the horizontal coordinate x1, i.e. the crankshaft rotation angle, is an important parameter for measuring the valve phase. Therefore, the crankshaft rotation angle x0 of the actual top dead center is obtained by correcting the crankshaft rotation angle of the piston top dead center through the above model.

[0081] In the fourth step, the valve lift at the opening time of the valve 5 or the closing time of the valve 5 is recorded as m, and the horizontal coordinate point corresponding to the valve lift m is read from the valve lift curve and the tappet lift curve diagram as shown in Figure 7 , the corresponding tappet lift is determined, and the tappet lift at this time is recorded as h, wherein m is 1 mm. When the first displacement measuring device 22 measures the tappet lift h, the second rotation angle α2 of the crankshaft is read through the encoder.

[0082] In the fifth step, the included angle β between the state of the crankshaft 3 at the piston top dead center and the state when the tappet lift is h is calculated through the first rotation angle α1 and the second rotation angle α2, wherein β=α2-α1.

[0083] In the sixth step, the rotation angle γ of the crankshaft 3 from the starting point of the valve lift m to the starting point of the movement of the tappet to the tappet lift h is obtained; the engine valve timing δ is calculated through β and γ, wherein δ=β-γ. The starting point of the valve lift m is the starting point of the piston at the actual top dead center, the crankshaft continues to rotate, drives the cam to rotate, and the cam starts to press down the valve.

[0084] Specifically, the step of obtaining the rotation angle γ of the crankshaft 3 comprises:

[0085] The rotation angle C of the cam 9 from the starting point of the valve lift m to the starting point of the movement of the tappet to the tappet lift h is obtained;

[0086] According to the rotation angle C, the rotation angle γ of the crankshaft 3 from the starting point of the valve lift m to the starting point of the movement of the tappet to the tappet lift h is calculated, wherein γ = 2 x C.

[0087] In summary, the embodiment of the present application provides an engine valve timing measurement device and measurement method. The measurement does not need to replace the hydraulic tappet inside the engine and adjust the first displacement measurement device parallel to the valve direction, which improves the efficiency. The timing chain is in tension state by the manual tensioner, which avoids causing measurement error. The tappet lift, piston displacement and crankshaft rotation angle are measured by the first displacement measurement device, the second displacement measurement device and the encoder, the data can be read by the computer, the piston top dead center is corrected by the program and the valve timing is calculated, which reduces the manual measurement error and improves the measurement accuracy.

[0088] The above is only the preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and substitutions can be made, which should also be considered as the protection scope of the present application.

Claims

1. An engine valve timing phase measuring device, characterized in that, Includes drive mechanism and measuring mechanism; The drive mechanism includes a motor and a coupling. The motor includes an encoder, and the output shaft of the motor is connected to the coupling, which is used to connect to the crankshaft of the engine. The measuring mechanism includes a base, a first displacement measuring device, a second displacement measuring device, and a pusher component, wherein the first displacement measuring device is disposed on the base; The tappet component includes a hollow tappet bracket, an elastic element and a tappet disposed inside the tappet bracket, the bottom of the tappet bracket is provided with a first mounting hole for fixed connection with the engine, and the top of the tappet bracket is provided with a measuring hole for the first displacement measuring device to pass through. The tappet is movably mounted on the lower part of the tappet bracket, and the lower part of the tappet is provided with a protrusion for engaging with the engine's cam. The elastic element is located above the push rod, and its two ends abut against the push rod and the push rod support, respectively. It also includes a manual tensioner, which includes a tension bolt and a tension seat. The tension seat has a threaded hole and a second mounting hole for fixed connection with the engine. The threaded hole passes through the tension seat. In the working state, the tension bolt passes through the threaded hole and presses against the timing chain guide of the engine. The manual tensioner is used to adjust the tension of the timing chain by means of the tension bolt before the crankshaft of the engine is rotated by the drive mechanism. The tappet includes a roller and a housing. The housing is connected to the inside of the tappet bracket through an anti-rotation structure. The inside of the housing has a cavity that runs through its upper and lower surfaces. A partition is provided in the middle of the cavity to divide it into an upper chamber and a lower chamber. The lower end of the elastic element is connected to the upper chamber. The roller is rotatably connected to the lower chamber and protrudes from the lower part of the housing to form the protrusion.

2. The engine valve timing measurement device according to claim 1, characterized in that... The anti-rotation structure includes a positioning pin on the outer side of the housing and a positioning groove on the inner side of the tappet bracket. The positioning pin is inserted into the positioning groove and can move up and down along the positioning groove to prevent the tappet from rotating with the tappet bracket during the up and down movement.

3. The engine valve timing phase measuring device according to claim 1, characterized in that... The base includes a magnetic base and a support arm. One end of the support arm is detachably connected to the magnetic base, and the first displacement measuring device is detachably connected to the other end of the support arm.

4. The engine valve timing phase measuring device according to claim 1, characterized in that... Both the first and second displacement measuring devices are dial indicators, the elastic element is a spring, the motor is a servo motor, and the coupling is a flexible coupling.

5. A method for measuring engine valve timing phase, characterized in that, The method is implemented using the engine valve timing measurement device as described in any one of claims 1-4, and the method includes the following steps: The tappet assembly is installed on the engine cylinder head, with the protrusion of the tappet abutting against the upper end of the cam. The first displacement measuring device passes through the measuring hole and abuts against the tappet, while the second displacement measuring device abuts against the engine piston. The tension of the timing chain can be manually adjusted using the tensioning bolt. The crankshaft that drives the engine rotates, which in turn drives the timing chain, causing the cam to rotate and the piston to move up and down as the crankshaft rotates. When the second displacement measuring device measures the displacement of the piston at its actual dead center as y1, the encoder reads the first rotation angle α1 of the crankshaft. The valve lift corresponding to the valve opening or closing moment is denoted as m. The horizontal coordinate point corresponding to the valve lift of m is read from the valve lift curve and tappet lift curve. The corresponding tappet lift is determined based on the horizontal coordinate point, and the tappet lift at this time is denoted as h. When the first displacement measuring device measures the tappet lift as h, the second crankshaft rotation angle α2 is read through the encoder. The angle β between the state of the crankshaft at the top dead center of the piston and the state of the tappet when the lift is h is calculated using the first rotation angle α1 and the second rotation angle α2, where β = α2 - α1; Obtain the crankshaft rotation angle γ from the starting point of valve lift m to the starting point of the tappet's upward movement to the tappet lift h; calculate the engine valve timing phase δ using β and γ, where δ = β - γ.

6. The engine valve timing phase measurement method according to claim 5, characterized in that, The actual dead center of the piston is obtained through the following steps: The piston's top dead center is measured by a second displacement measuring device, and the top dead center is corrected to obtain the piston's actual dead center.

7. The engine valve timing phase measurement method according to claim 6, characterized in that, The method for correcting the actual dead center of the piston includes the following steps: The displacement y of the piston is measured by the second displacement measuring device. At the same time, the crankshaft rotation angle x corresponding to the piston displacement y is read by the encoder, and the coordinates (x1, y1) of the piston top dead center are obtained. The previous point (x2, y2) and the next point (x3, y3) of the piston top dead center are also obtained. The actual x-coordinate x0 corresponding to the endpoint is corrected using the following model: x0=x2+0.5×a×(4×y1-3×y2-y3) / (2×y1-y2-y3); Obtain the displacement y0 of the piston when the crankshaft rotation angle is x0; The coordinates of the actual dead center of the piston are (x0, y0). Where a represents the step size, x0 represents the crankshaft angle at the actual dead center after correction, y0 represents the piston displacement at the actual dead center after correction, x1, x2 and x3 represent the crankshaft angles output by the encoders corresponding to the three points, and y1, y2 and y3 represent the piston displacements output by the second displacement measuring device corresponding to the three points.

8. The engine valve timing phase measurement method according to claim 5, characterized in that, The step of obtaining the rotation angle γ of the crankshaft from the starting point of the valve lift m to the starting point of the upward movement of the tappet to the tappet lift h includes: Obtain the angle C of the cam from the starting point of the valve lift m to the starting point of the upward movement of the tappet to the tappet lift h; The crankshaft rotation angle γ is calculated based on the rotation angle C, from the starting point of valve lift m to the starting point of the upward movement of the tappet to the starting point of the tappet lift h, where γ = 2 × C.

9. The engine valve timing phase measurement method according to claim 5, characterized in that, The valve lift m corresponding to the valve opening or closing time is 1 mm.

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