Engine mechanical timing adjustment method

Abstract

The application discloses an engine mechanical timing adjustment method, and belongs to the technical field of engines.The engine mechanical timing adjustment method comprises the following steps: after the assembly of an engine timing chain is completed, the mechanical timing is measured, and a camshaft timing actual measurement value is obtained; a mechanical timing deviation is obtained according to the camshaft timing actual measurement value and a camshaft timing theoretical value; a camshaft timing state is obtained according to the mechanical timing deviation; and a corresponding camshaft timing adjustment strategy is executed according to the camshaft timing state.The engine mechanical timing adjustment method disclosed by the application firstly measures the mechanical timing and obtains the camshaft timing actual measurement value after the assembly of the engine timing chain is completed, then obtains the mechanical timing deviation according to the camshaft timing actual measurement value and the camshaft timing theoretical value, obtains the camshaft timing state according to the mechanical timing deviation, and finally executes the corresponding camshaft timing adjustment strategy according to the camshaft timing state, so that the assembly efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application discloses an engine mechanical timing adjustment method and belongs to the technical field of engines. BACKGROUND

[0002] Valve timing is an important factor affecting the charge efficiency of an engine, and its accuracy directly affects the power and economy of the engine. Valve timing specifically refers to the fact that, when the engine is running, the crankshaft and the camshaft are at the correct positions at the correct time, so as to ensure that the camshaft drives the intake and exhaust valves to open and close at the specified time.

[0003] During the assembly of the engine, the crankshaft and the camshaft are positioned through a certain positioning method, locked through bolts, and connected through a chain. At this time, the relative positions of the crankshaft and the camshaft are fixed, and subsequent linkage is performed according to the initial relative positions. Therefore, the accuracy of the initial relative positions of the crankshaft and the camshaft directly affects the accuracy of the valve timing of the engine in the later stage. This valve timing which is completely guaranteed by mechanical accuracy can be referred to as the mechanical timing of the engine. During the assembly of the engine, the accuracy of the mechanical timing of the engine is generally judged by checking the phase of the camshaft.

[0004] During the mass production stage, considering the machining error of parts, the error of assembly tooling, and the detection error, the precision of the phase of the camshaft is generally required to be within ±3°, so as to meet the performance requirements of the mass-produced engine. However, during the development stage of the engine, especially during the development stage of the whole machine calibration, the precision of the phase of the camshaft is extremely important, and its accuracy directly affects the calibration results of the whole machine. Therefore, during the development stage of the engine, the phase error of the camshaft is generally required to be within ±1°.

[0005] At present, the cumulative tolerance of the related parts of the engine, including the crankshaft, the cylinder block, the camshaft frame, the camshaft, the crankshaft timing pin and the camshaft timing pin, reaches 3 degrees, and the assembly cannot guarantee that the timing precision is within ±1 degree. Only repeated replacement, reassembly and detection can be performed until the parts are qualified, which is low in efficiency and high in randomness. SUMMARY

[0006] The application aims to solve the problems of the existing engine valve timing assembly, such as high randomness and low efficiency, and provides an engine mechanical timing adjustment method.

[0007] The problems solved by the application are achieved by the following technical scheme:

[0008] An engine mechanical timing adjustment method comprises the following steps:

[0009] After the timing chain of the engine is assembled, the mechanical timing is measured, and the actual measured value of the camshaft timing is obtained;

[0010] The mechanical timing deviation is obtained according to the actual measured value of the camshaft timing and the theoretical value of the camshaft timing.

[0011] obtaining a camshaft timing state according to the mechanical timing deviation;

[0012] executing a corresponding camshaft timing adjustment strategy according to the camshaft timing state.

[0013] Preferably, the camshaft timing measured value comprises: an intake camshaft timing measured value or an exhaust camshaft timing measured value.

[0014] Preferably, the mechanical timing deviation is obtained according to the camshaft timing measured value and a camshaft timing theoretical value, comprising:

[0015] when the camshaft timing measured value is an intake camshaft timing measured value:

[0016] obtaining an intake mechanical timing deviation according to the intake camshaft timing measured value and an intake camshaft timing theoretical value;

[0017] when the camshaft timing measured value is an exhaust camshaft timing measured value:

[0018] obtaining an exhaust mechanical timing deviation according to the exhaust camshaft timing measured value and an exhaust camshaft timing theoretical value.

[0019] Preferably, the camshaft timing state is obtained according to the mechanical timing deviation, comprising:

[0020] when the mechanical timing deviation is an intake mechanical timing deviation:

[0021] when the intake mechanical timing deviation is positive, the camshaft timing state is an intake camshaft timing lag state;

[0022] when the intake mechanical timing deviation is negative, the camshaft timing state is an intake camshaft timing advance state;

[0023] when the mechanical timing deviation is an exhaust mechanical timing deviation:

[0024] when the exhaust mechanical timing deviation is positive, the camshaft timing state is an exhaust camshaft timing lag state;

[0025] when the exhaust mechanical timing deviation is negative, the camshaft timing state is an exhaust camshaft timing advance state.

[0026] Preferably, the corresponding camshaft timing adjustment strategy is executed according to the camshaft timing state, comprising:

[0027] when only the exhaust camshaft timing lag state or the intake camshaft timing lag state exists, a corresponding camshaft timing lag adjustment strategy is executed, and the step is same;

[0028] when only the exhaust camshaft timing advance state or the intake camshaft timing advance state, performing the same step of the corresponding camshaft timing advance adjustment strategy;

[0029] when the exhaust camshaft and intake camshaft timing lag / advance state, performing the same step of the corresponding camshaft simultaneous timing adjustment strategy.

[0030] Preferably, the corresponding camshaft timing lag adjustment strategy comprises:

[0031] performing the preparation strategy before adjusting the corresponding camshaft timing;

[0032] performing the corresponding camshaft timing lag adjustment strategy, comprising:

[0033] read the crankshaft angle by the angle gauge, loosen the VCT sprocket anti-rotation tool positioning plate, first rotate the crankshaft counterclockwise by 30 degrees using a wrench, then rotate the crankshaft clockwise by the difference between 30 degrees and the corresponding exhaust mechanical timing deviation, to the number of degrees that is the difference between the crankshaft angle and the corresponding exhaust mechanical timing deviation;

[0034] reinstall the VCT sprocket anti-rotation tool positioning plate, position the corresponding VCT sprocket, tighten the corresponding VCT bolt, and pull out the corresponding camshaft timing pin, and the error adjustment is complete.

[0035] Preferably, the corresponding camshaft timing advance adjustment strategy comprises:

[0036] performing the preparation strategy before adjusting the corresponding camshaft timing;

[0037] performing the corresponding camshaft timing advance adjustment strategy, comprising:

[0038] read the crankshaft angle by the angle gauge, loosen the VCT sprocket anti-rotation tool positioning plate, rotate the crankshaft clockwise by the absolute value of the corresponding exhaust mechanical timing deviation, to the number of degrees that is the sum of the crankshaft angle and the absolute value of the corresponding exhaust mechanical timing deviation;

[0039] reinstall the VCT sprocket anti-rotation tool positioning plate, position the corresponding VCT sprocket, tighten the corresponding VCT bolt, and pull out the corresponding camshaft timing pin, and the error adjustment is complete.

[0040] Preferably, the preparation strategy before adjusting the corresponding camshaft timing comprises:

[0041] rotate the crankshaft clockwise from the front end of the engine through the crankshaft pulley bolt, to the corresponding camshaft timing position, and install the corresponding camshaft timing pin;

[0042] Position the corresponding VCT sprocket by using the VCT sprocket anti-rotation tool; loosen the corresponding VCT bolt, and the corresponding VCT sprocket can rotate freely relative to the corresponding camshaft.

[0043] Preferably, the corresponding camshaft simultaneous timing adjustment strategy comprises:

[0044] Rotate the crankshaft clockwise through the crankshaft pulley bolt from the front end of the engine to the timing position of one of the intake camshaft or the exhaust camshaft, and install the intake camshaft timing pin or the exhaust camshaft timing pin;

[0045] Then position one of the intake VCT sprocket or the exhaust VCT sprocket by using the VCT sprocket anti-rotation tool;

[0046] Loosen the intake VCT bolt or the exhaust VCT bolt, and at this time one of the intake VCT sprocket or the exhaust VCT sprocket can rotate freely relative to the intake camshaft / exhaust camshaft;

[0047] Continue to rotate the crankshaft clockwise, repeat the above steps until the other one of the intake VCT sprocket or the exhaust VCT sprocket can rotate freely relative to the intake camshaft / exhaust camshaft, and then perform the next step;

[0048] According to the exhaust camshaft and intake camshaft timing lag / advance state, perform the corresponding camshaft timing lag adjustment strategy or the corresponding camshaft timing advance adjustment strategy.

[0049] Preferably, after the corresponding camshaft timing adjustment strategy is performed according to the camshaft timing state, the method further comprises: re-measuring the mechanical timing and recording the mechanical timing deviation.

[0050] The present application has the following beneficial effects relative to the prior art:

[0051] The present application discloses an engine mechanical timing adjustment method, which comprises the following steps: first, measuring the mechanical timing and obtaining the camshaft timing actual value after the engine timing chain is assembled; then, obtaining the mechanical timing deviation according to the camshaft timing actual value and the camshaft timing theoretical value; finally, performing the corresponding camshaft timing adjustment strategy according to the camshaft timing state, thereby improving the assembly efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is a flowchart of the engine mechanical timing adjustment method of the present application.

[0053] Figure 2 is a schematic diagram of the engine valve timing of the present application.

[0054] Figure 3 is a schematic diagram of the engine chain system of the present application.

[0055] Figure 4 Figure 1 is a schematic diagram of the initial position of the crankshaft and camshaft of the present application.

[0056] Figure 5 Figure 2 is a schematic diagram of the anti-rotation tool for the VCT sprocket of the present application.

[0057] Wherein:

[0058] 1 - crankshaft;

[0059] 2 - intake camshaft;

[0060] 3 - exhaust camshaft;

[0061] 4 - intake VCT bolt;

[0062] 5 - intake VCT sprocket;

[0063] 6 - exhaust VCT sprocket;

[0064] 7 - exhaust VCT bolt;

[0065] 8 - timing chain;

[0066] 9 - crankshaft pulley bolt;

[0067] 10 - crankshaft sprocket;

[0068] 11 - crankshaft timing pin;

[0069] 12 - intake camshaft timing pin;

[0070] 13 - exhaust camshaft timing pin;

[0071] 14 - anti-rotation tool for VCT sprocket;

[0072] 15 - positioning plate. DETAILED DESCRIPTION

[0073] The technical solutions of the present application will be described below in detail with reference to the accompanying drawings. Figures 1-5 The present application is further described as follows:

[0074] The technical solutions of the present application will be described below in detail with reference to the accompanying drawings.

[0075] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship 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 do not indicate or imply 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 a limitation on the present application.

[0076] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0077] As shown in Figures 1-5 The first embodiment of the present application provides an engine mechanical timing adjustment method based on the prior art, comprising:

[0078] Step 101, after the engine timing chain is assembled, the mechanical timing is measured and the camshaft timing measured value is obtained.

[0079] The camshaft timing measured value includes: intake camshaft timing measured value or exhaust camshaft timing measured value.

[0080] Step 102, according to the camshaft timing measured value and the camshaft timing theoretical value, the mechanical timing deviation is obtained, and the specific content is as follows:

[0081] When the camshaft timing measured value is the intake camshaft timing measured value:

[0082] According to the difference between the intake camshaft timing measured value and the intake camshaft timing theoretical value, the intake mechanical timing deviation is obtained;

[0083] When the camshaft timing measured value is the exhaust camshaft timing measured value:

[0084] According to the difference between the exhaust camshaft timing measured value and the exhaust camshaft timing theoretical value, the exhaust mechanical timing deviation is obtained.

[0085] Step 103, according to the mechanical timing deviation, the camshaft timing state is obtained, and the specific content is as follows:

[0086] When the mechanical timing deviation is the intake mechanical timing deviation:

[0087] When the intake mechanical timing deviation is positive, the camshaft timing state is an intake camshaft timing lag state;

[0088] When the intake mechanical timing deviation is negative, the camshaft timing state is an intake camshaft timing advance state;

[0089] When the mechanical timing deviation is an exhaust mechanical timing deviation:

[0090] When the exhaust mechanical timing deviation is positive, the camshaft timing state is an exhaust camshaft timing lag state;

[0091] When the exhaust mechanical timing deviation is negative, the camshaft timing state is an exhaust camshaft timing advance state.

[0092] Step 104, according to the camshaft timing state, a corresponding camshaft timing adjustment strategy is executed, and the specific content is as follows:

[0093] When only the exhaust camshaft timing lag state or the intake camshaft timing lag state exists, a corresponding camshaft timing lag adjustment strategy is executed, and the specific content is as follows:

[0094] A corresponding camshaft timing lag adjustment strategy is executed, and the specific content is as follows:

[0095] A corresponding camshaft timing lag adjustment strategy is executed, and the specific content is as follows:

[0096] The crankshaft angle is read through the protractor, the VCT sprocket anti-rotation tool positioning plate 15 is loosened, the crankshaft is counterclockwise rotated by 30 degrees through a wrench, and then the crankshaft is clockwise rotated by a number of degrees equal to the difference between 30 and the corresponding exhaust mechanical timing deviation, so as to be rotated to a number of degrees equal to the difference between the crankshaft angle and the corresponding exhaust mechanical timing deviation;

[0097] The VCT sprocket anti-rotation tool positioning plate 15 is re-installed, the corresponding VCT sprocket is positioned, the corresponding VCT bolt is tightened, and the corresponding camshaft timing pin is pulled out, and the error adjustment is completed.

[0098] When only the exhaust camshaft timing advance state or the intake camshaft timing advance state exists, a corresponding camshaft timing advance adjustment strategy is executed, and the specific content is as follows:

[0099] A corresponding camshaft timing advance adjustment strategy is executed, and the specific content is as follows:

[0100] A corresponding camshaft timing advance adjustment strategy is executed, and the specific content is as follows:

[0101] The crankshaft angle is read through the protractor, the VCT sprocket anti-rotation tool positioning plate 15 is loosened, the crankshaft is clockwise rotated by a number of degrees equal to the absolute value of the corresponding exhaust mechanical timing deviation through a wrench, and then the crankshaft is rotated to a number of degrees equal to the sum of the crankshaft angle and the absolute value of the corresponding exhaust mechanical timing deviation;

[0102] Install the VCT sprocket anti-rotation tool positioning plate 15 again, position the corresponding VCT sprocket, tighten the corresponding VCT bolt 4, and pull out the corresponding camshaft timing pin. The error adjustment is complete.

[0103] The preparation strategy before adjusting the corresponding camshaft timing in the above steps includes:

[0104] Turn the crankshaft 1 clockwise through the crankshaft pulley bolt 9 from the front end of the engine to the corresponding camshaft timing position, and install the corresponding camshaft timing pin.

[0105] Use the VCT sprocket anti-rotation tool 14 to position the corresponding VCT sprocket; loosen the corresponding VCT bolt, and the corresponding VCT sprocket can rotate freely relative to the corresponding camshaft.

[0106] Taking the intake camshaft as an example, the adjustment steps are introduced in detail for camshaft timing lag adjustment and camshaft timing advance adjustment, respectively.

[0107] When the mechanical timing deviation C is positive, the camshaft timing lags, and the adjustment method is as follows:

[0108] First, turn the crankshaft 1 clockwise through the crankshaft pulley bolt 9 from the front end of the engine to the intake camshaft 2 timing position, and install the intake camshaft timing pin 12.

[0109] Then use the VCT sprocket anti-rotation tool 14 to position the intake VCT sprocket 5; loosen the intake VCT bolt 4, and at this time the intake VCT sprocket 5 can rotate freely relative to the intake camshaft 2;

[0110] Read the crankshaft angle D through the protractor, loosen the VCT sprocket anti-rotation tool positioning plate 15, first turn the crankshaft 130 degrees counterclockwise (facing the front end of the engine), then turn the crankshaft (30-C) degrees clockwise (facing the front end of the engine), and turn to (D-C) degrees.

[0111] Install the VCT sprocket anti-rotation tool positioning plate 15 again, position the intake VCT sprocket 5, tighten the intake VCT bolt 4, and pull out the intake camshaft timing pin 12. The error adjustment is complete. Recheck the mechanical timing and record the mechanical timing deviation.

[0112] When the mechanical timing deviation C is negative, the camshaft timing advances, and the adjustment method is as follows:

[0113] First, turn the crankshaft 1 clockwise through the crankshaft pulley bolt 9 from the front end of the engine to the intake camshaft 2 timing position, and install the intake camshaft timing pin 12.

[0114] Then use the VCT sprocket anti-rotation tool 14 to position the intake VCT sprocket 5; loosen the intake VCT bolt 4, and at this time the intake VCT sprocket 5 can rotate freely relative to the intake camshaft 2;

[0115] Read the crank angle D by the protractor, loosen the VCT sprocket anti-rotation fixture positioning plate 15, rotate the crankshaft 1 clockwise (facing the front end of the engine) by |C| degrees using a wrench, and turn to (D+|C|) degrees;

[0116] Install the VCT sprocket anti-rotation fixture positioning plate 15 again, position the intake VCT sprocket 5, tighten the intake VCT bolt 4, and pull out the intake camshaft timing pin 12. The error adjustment is complete. Recheck the mechanical timing and record the mechanical timing deviation.

[0117] If both the intake and exhaust camshafts have deviations during assembly, adjusting them at the same time is more time-saving and efficient. Therefore, when the exhaust camshaft and the intake camshaft are in a timing lag / advance state, the same corresponding camshaft timing adjustment strategy is executed, including:

[0118] Rotate the crankshaft 1 clockwise through the crankshaft pulley bolt 9 from the front end of the engine, turn to one of the timing positions of the intake camshaft 2 or the exhaust camshaft 3, and install the intake camshaft timing pin 12 or the exhaust camshaft timing pin 13;

[0119] Use the VCT sprocket anti-rotation fixture 14 again to position one of the intake VCT sprocket 5 or the exhaust VCT sprocket 6;

[0120] Loosen the intake VCT bolt 4 or the exhaust VCT bolt 7, at which time one of the intake VCT sprocket 5 or the exhaust VCT sprocket 6 can rotate freely relative to the intake camshaft 2 / exhaust camshaft 3;

[0121] Continue to rotate the crankshaft 1 clockwise, repeat the above steps until the other of the intake VCT sprocket 5 or the exhaust VCT sprocket 6 can rotate freely relative to the intake camshaft 2 / exhaust camshaft 3, and then execute the next step;

[0122] According to the timing lag / advance state of the exhaust camshaft and the intake camshaft, execute the corresponding camshaft timing lag strategy or the corresponding camshaft timing advance strategy.

[0123] After executing the corresponding camshaft timing adjustment strategy according to the camshaft timing state as described above, recheck the mechanical timing and record the mechanical timing deviation.

[0124] The following takes the intake camshaft timing lag of 3 degrees as an example to introduce the adjustment steps in detail.

[0125] Measure the engine mechanical timing, obtain the average value A of the intake camshaft 2 phase measurement: 428 degrees, the theoretical value a of the intake camshaft 2 phase: 425 degrees, and calculate A-a=3 degrees by formula. At this time, it can be judged that the intake camshaft 2 timing lags 3 degrees relative to the crankshaft 1 phase.

[0126] First clockwise rotate the crankshaft 1 through the crankshaft pulley bolt 9 from the front end of the engine, rotate to the intake camshaft 2 timing position, install the intake camshaft timing pin 13; Then use the VCT sprocket anti-rotation tool 14 to position the intake VCT sprocket 5; Loosen the intake VCT bolt 4, at this time the intake VCT sprocket 5 can rotate freely relative to the camshaft; Read the crankshaft angle D through the protractor: 65 degrees, loosen the VCT sprocket anti-rotation tool positioning plate 15, first use the wrench to rotate the crankshaft counterclockwise (facing the front end of the engine) 30 degrees, then rotate the crankshaft clockwise (facing the front end of the engine) (30-C) = 27 degrees, rotate to (D-C) = 62 degrees; Install the VCT sprocket anti-rotation tool positioning plate 15 again, position the intake VCT sprocket 5, tighten the intake VCT bolt 4, pull out the intake camshaft timing pin 12, the error adjustment is complete. Recheck the mechanical timing, record the mechanical timing deviation.

[0127] While the embodiments of the application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments. It can be fully applied to various fields suitable for the application. Additional modifications can be easily made by those skilled in the art. Therefore, the application is not limited to specific details and the figures shown and described herein without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. An engine mechanical timing adjustment method, characterized by, The method comprises the following steps: After the engine timing chain (8) is assembled, the mechanical timing is measured and the camshaft timing actual value is obtained; The mechanical timing deviation is obtained according to the camshaft timing actual value and the camshaft timing theoretical value; The camshaft timing state is obtained according to the mechanical timing deviation; The corresponding camshaft timing adjustment strategy is executed according to the camshaft timing state; The camshaft timing state obtained according to the mechanical timing deviation comprises: When the mechanical timing deviation is the intake mechanical timing deviation: When the intake mechanical timing deviation is positive, the camshaft timing state is the intake camshaft timing lag state; When the intake mechanical timing deviation is negative, the camshaft timing state is the intake camshaft timing advance state; When the mechanical timing deviation is the exhaust mechanical timing deviation: When the exhaust mechanical timing deviation is positive, the camshaft timing state is the exhaust camshaft timing lag state; When the exhaust mechanical timing deviation is negative, the camshaft timing state is the exhaust camshaft timing advance state; The corresponding camshaft timing adjustment strategy executed according to the camshaft timing state comprises: When only the exhaust camshaft timing lag state or the intake camshaft timing lag state exists, the corresponding camshaft timing lag adjustment strategy is executed; When only the exhaust camshaft timing advance state or the intake camshaft timing advance state exists, the corresponding camshaft timing advance adjustment strategy is executed; When the exhaust camshaft and the intake camshaft timing lag / advance state exist, the corresponding camshaft simultaneous timing adjustment strategy is executed; The corresponding camshaft timing lag adjustment strategy comprises: The corresponding camshaft timing advance adjustment strategy comprises: The corresponding camshaft timing lag adjustment strategy comprises: The corresponding camshaft timing advance adjustment strategy comprises: The corresponding camshaft simultaneous timing adjustment strategy comprises: ​ ​ ​ ​ ​ ​ Step (a), rotate the crankshaft (1) clockwise through the crankshaft pulley bolt (9) from the front end of the engine to one of the intake camshaft (2) or exhaust camshaft (3) timing position, install the intake camshaft timing pin (12) or exhaust camshaft timing pin (13); Step (b), use the VCT sprocket anti-rotation tooling (14) to position one of the intake VCT sprocket (5) or exhaust VCT sprocket (6); Step (c), loosen the intake VCT bolt (4) or exhaust VCT bolt (7), at this time one of the intake VCT sprocket (5) or exhaust VCT sprocket (6) can rotate freely relative to the intake camshaft (2) / exhaust camshaft (3); Step (d), continue to rotate the crankshaft (1) clockwise, repeat steps (a), (b) and (c) until the other of the intake VCT sprocket (5) or exhaust VCT sprocket (6) can rotate freely relative to the intake camshaft (2) / exhaust camshaft (3), then perform the next step; Step (e), according to the exhaust camshaft and intake camshaft timing lag / advance state, execute the corresponding camshaft timing lag adjustment strategy or the corresponding camshaft timing advance adjustment strategy.

2. An engine mechanical timing adjustment method according to claim 1, characterized in that, The camshaft timing actual value includes: intake camshaft timing actual value or exhaust camshaft timing actual value.

3. An engine mechanical timing adjustment method according to claim 2, characterized in that, The mechanical timing deviation obtained according to the camshaft timing actual value and the camshaft timing theoretical value includes: When the camshaft timing actual value is the intake camshaft timing actual value: According to the intake camshaft timing actual value and the intake camshaft timing theoretical value, obtain the intake mechanical timing deviation; When the camshaft timing actual value is the exhaust camshaft timing actual value: According to the exhaust camshaft timing actual value and the exhaust camshaft timing theoretical value, obtain the exhaust mechanical timing deviation.

4. An engine mechanical timing adjustment method according to claim 3, characterized in that, The execution of the corresponding camshaft timing preparation strategy before adjustment includes: Rotate the crankshaft (1) clockwise through the crankshaft pulley bolt (9) from the front end of the engine to the corresponding camshaft timing position, install the corresponding camshaft timing pin; Use the VCT sprocket anti-rotation tooling (14) to position the corresponding VCT sprocket; loosen the corresponding VCT bolt, and the corresponding VCT sprocket can rotate freely relative to the corresponding camshaft.

5. The method of claim 1, wherein, After the execution of the corresponding camshaft timing adjustment strategy according to the camshaft timing state, it further includes: re-measuring the mechanical timing and recording the mechanical timing deviation.

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