Engine valve timing measuring device and method based on pure machinery
By constructing a purely mechanical dual-reference linkage design, an engine valve timing phase measurement device is built, which solves the problems of measurement lag and insufficient versatility in the existing technology, and realizes high-precision and low-cost engine valve timing phase measurement, which is applicable to various engine structures and complex operating conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN DONGAN AUTO ENGINE CO LTD
- Filing Date
- 2026-01-28
- Publication Date
- 2026-04-17
AI Technical Summary
Existing engine valve timing measurement technologies suffer from problems such as measurement lag caused by hydraulic tappets, lack of correlation between angle and displacement in traditional methods, strong subjectivity, high cost, and insufficient versatility, making it difficult to achieve high-precision, high-repeatability, and low-cost measurements.
It adopts a purely mechanical dual-reference linkage design, constructing a "piston-measuring rod-dial gauge" sensing chain through rigid tappets, and combining the dial and crankshaft adapter plate to establish a synchronous relationship between crankshaft angle and valve displacement, thereby achieving accurate measurement.
It improves the accuracy and repeatability of measurements, reduces composite errors, is applicable to various engine structures, is low in cost and highly adaptable to the environment, and is suitable for final inspection on the production line, R&D verification and maintenance scenarios.
Smart Images
Figure CN121877401A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of internal combustion engine testing technology, and particularly relates to a purely mechanical engine valve timing measurement device and method. Background Technology
[0002] Valve timing is a core parameter for evaluating the performance of an engine's valve train, referring to the opening and closing times and durations of the intake and exhaust valves, expressed as crankshaft angles. Its accuracy directly affects the engine's charging efficiency, combustion stability, power output, and emissions levels. Existing engine valve timing measurement technologies suffer from several problems: the delayed compression and depressurization of hydraulic tappets easily leads to lag in valve opening phase measurements, failing to accurately reflect the mechanical assembly state; traditional mechanical methods lack the correlation between angle and displacement, resulting in a single measurement benchmark and difficulty in controlling system errors; reliance on manual judgment of piston top dead center is subjective and lacks repeatability; electronic measurement equipment depends on power supply and signal processing systems, is costly, and unsuitable for complex operating conditions; existing devices lack versatility and are difficult to adapt to different engine structures such as OHV, SOHC, and DOHC, as well as various drive methods. Therefore, a high-precision, highly repeatable, low-cost, interference-resistant, and highly versatile purely mechanical measurement solution is urgently needed to address these technical problems. Summary of the Invention
[0003] The purpose of this invention is to provide an engine valve timing measurement device and method based on a purely mechanical dual-reference linkage. By using a rigid tappet to avoid the nonlinear effects of a hydraulic tappet, and by using a "piston-measuring rod-dial gauge" sensing chain to accurately locate the top dead center, a dual-reference synchronous relationship between the crankshaft angle and the valve displacement is established, thereby achieving accurate measurement of the valve opening / closing phase and improving measurement reliability and versatility.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A purely mechanical engine valve timing measurement device includes a probe fixture, a probe, a dial indicator, a scale, a pointer, and a crankshaft adapter plate. The probe fixture is set in the spark plug hole of the cylinder head. The probe is mounted on the probe fixture, and its upper and lower ends respectively contact the dial indicator and the piston top to form a "piston-probe-dial indicator" sensing chain mechanism. The scale is mounted on the rear flange surface of the crankshaft. The crankshaft adapter plate is mounted on the scale. The pointer is set and used in conjunction with the scale to point to the scale, so as to read the scale value and determine the reference angle.
[0005] Furthermore, the measuring rod tooling is provided with a measuring rod hole and a spark plug mating thread. The spark plug mating thread is used to engage with the spark plug thread hole of the cylinder head. The measuring rod is inserted into the measuring rod hole, with one end used to abut against the piston top and the other end used to abut against the dial indicator probe.
[0006] Furthermore, the dial is provided with a dial center hole, dial bolt holes, and dial pin holes. The dial center hole is used to mate with the crankshaft stop, the dial pin holes are used to mate with the crankshaft pins, and the dial bolt holes are used to fix the dial to the crankshaft rear flange surface with bolts. The turning gear adapter is provided with a turning gear cap, adapter bolt holes, and adapter pin holes. The turning gear adapter is installed on the dial through the adapter bolt holes and bolts, and the adapter pin holes are configured and used in conjunction with the dial pin holes.
[0007] An engine valve timing phase measurement method utilizing the aforementioned purely mechanical engine valve timing phase measurement device, the method comprising the following steps:
[0008] Step 1: Establish initial measurement conditions: Assemble the cylinder head system, cylinder block, and crankshaft system components, install the rigid tappets, and then assemble the timing system; if it is a complete machine, remove the peripheral components and timing system, replace the hydraulic tappets with rigid tappets, and then restore the timing system;
[0009] Step 2: Top Dead Center Measurement: Screw the test rod into the spark plug threaded hole of the cylinder head through the spark plug mating thread. The test rod passes through the test rod hole and abuts against the piston top. The dial indicator probe abuts against the top of the test rod. Rotate the crankshaft and determine the limit position of the test rod's ascent by reading the dial indicator. This is the piston's top dead center.
[0010] Step 3: Installation of dial and crankshaft adapter plate: Connect the dial to the crankshaft through the center hole and pin hole, and fix it to the rear flange face of the crankshaft through the bolt holes; install the crankshaft adapter plate on the dial through the adapter plate bolt holes and adapter plate pin holes, set the pointer to point to the dial, and determine the reference angle value A corresponding to the top dead center;
[0011] Step 4: Valve opening and closing timing measurement: Place the dial indicator probe against the valve spring seat plane, slowly rotate the crankshaft using the cranking adapter, and monitor the dial indicator pointer. When the pointer deviates by ≥0.01mm, read the dial value B and calculate the valve opening timing phase θopen=BA; record the dial angle B1 when the valve lift is 0.05mm, 0.55mm, and 1.05mm, and the dial angle B2 when the valve lift is 1.05mm, 0.55mm, and 0.05mm during the valve closing process. Obtain the opening and closing timing phases of the corresponding lifts by the differences between B1 and A, and between B2 and A.
[0012] Furthermore, in step four, the difference between the actual value measured and the theoretical phase at the opening and closing times corresponding to each lift is the phase deviation.
[0013] Compared with the prior art, the beneficial effects of the present invention are:
[0014] 1. This invention replaces the traditional hydraulic tappet with a rigid tappet with an oil-free cavity structure, achieving completely rigid force transmission, completely eliminating nonlinear interferences such as hydraulic medium compression and pressure relief delay, restoring the true mechanical phase of the engine, and improving measurement accuracy.
[0015] 2. This invention constructs a "piston-measuring rod-dial gauge" sensing chain mechanism. By combining the precise cooperation between the measuring rod and the measuring rod tooling, the top dead center position of the piston can be accurately captured, which solves the problems of strong subjectivity and poor repeatability of manual judgment of the top dead center and improves the measurement repeatability.
[0016] 3. This invention adopts a linkage design between the dial and the crankshaft adapter plate to establish a spatial synchronous relationship between the "crankshaft angle reference" and the "valve displacement reference". The angle value is read while cranking, which greatly reduces the compound error and improves the measurement efficiency and accuracy.
[0017] 4. This invention has a high degree of freedom and strong versatility. It is applicable to various gas distribution mechanisms such as OHV, SOHC, and DOHC, and is compatible with different drive methods such as hydraulic tappets, mechanical tappets, roller rocker arms, and finger rocker arms. It can be applied to various scenarios such as final inspection of production lines, R&D verification, and maintenance.
[0018] 5. The pure mechanical structure design of this invention does not rely on power supply and signal processing systems, has low cost and strong environmental adaptability, and can work stably under complex working conditions. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the upper dead point measurement of the present invention;
[0020] Figure 2 This is a schematic diagram of the measuring rod tooling of the present invention;
[0021] Figure 3 This is a schematic diagram of the dial of the present invention;
[0022] Figure 4 This is a schematic diagram of the rotary car adapter plate of the present invention;
[0023] Figure 5 This is a schematic diagram of the angle measurement of the present invention.
[0024] The component names and reference numerals in the above figures are as follows:
[0025] 1. Test bar fixture; 2. Test bar hole; 3. Spark plug mating thread; 4. Cylinder head; 5. Spark plug hole; 6. Spark plug threaded hole; 7. Valve spring seat; 8. Dial; 9. Dial center hole; 10. Dial bolt hole; 11. Dial pin hole; 12. Turning gear adapter plate; 13. Turning gear cap; 14. Adapter plate bolt hole; 15. Adapter plate pin hole; 16. Cylinder block. Detailed Implementation
[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0027] Detailed implementation methods: such as Figures 1-5 As shown, this embodiment discloses a purely mechanical engine valve timing measurement device, including a probe fixture 1, a probe, a dial indicator, a dial 8, a pointer, and a crankshaft adapter 12. The probe fixture 1 is disposed in the spark plug hole 5 of the cylinder head 4. The probe is mounted on the probe fixture 1, with its upper and lower ends respectively contacting the dial indicator and the piston top to form a "piston-probe-dial indicator" sensing chain mechanism. The dial 8 is mounted on the rear flange surface of the crankshaft. The crankshaft adapter 12 is mounted on the dial 8. The pointer is disposed on the cylinder block, slightly higher than the dial 8. The pointer is configured and used in conjunction with the dial 8 to point to the dial 8, facilitating the reading of the scale value and the determination of the reference angle.
[0028] Furthermore, the measuring rod tool 1 is provided with a measuring rod hole 2 and a spark plug mating thread 3. The spark plug mating thread 3 is used to engage with the spark plug threaded hole 6 of the cylinder head 4. The measuring rod is inserted into the measuring rod hole 2, with one end used to abut against the piston top and the other end used to abut against the dial indicator probe.
[0029] Furthermore, the dial 8 is provided with a dial center hole 9, a dial bolt hole 10, and a dial pin hole 11. The dial center hole 9 is used to mate with the crankshaft stop, the dial pin hole 11 is used to mate with the crankshaft pin, and the dial bolt hole 10 is used to fix the dial 8 to the crankshaft rear flange surface by bolts. The turning gear adapter 12 is provided with a turning gear cap 13, an adapter bolt hole 14, and an adapter pin hole 15. The turning gear adapter 12 is installed on the dial 8 through the adapter bolt hole 14 and bolts, and the adapter pin hole 15 is configured and used in conjunction with the dial pin hole 11.
[0030] An engine valve timing phase measurement method utilizing the aforementioned purely mechanical engine valve timing phase measurement device, the method comprising the following steps:
[0031] Step 1: Establish initial measurement conditions: Assemble the cylinder head system, cylinder block, and crankshaft system components, install the rigid tappets, and then assemble the timing system; if it is a complete machine, remove the peripheral components and timing system, replace the hydraulic tappets with rigid tappets, and then restore the timing system;
[0032] Step 2: Top Dead Center Measurement: Screw the test rod tool 1 into the spark plug threaded hole 6 of the cylinder head 4 through the spark plug mating thread 3. The test rod passes through the test rod hole 2 and abuts against the piston top. The dial indicator probe abuts against the top of the test rod. Rotate the crankshaft and determine the upper limit position of the test rod by reading the dial indicator. This is the piston top dead center.
[0033] Step 3: Installation of dial 8 and crankshaft adapter 12: Connect dial 8 to the crankshaft through the dial center hole 9 and dial pin hole 11, and fix it to the rear flange of the crankshaft through the dial bolt holes 10; install crankshaft adapter 12 onto dial 8 through adapter bolt holes 14 and adapter pin holes 15, set the pointer to dial 8, and determine the reference angle value A corresponding to the top dead center;
[0034] Step 4: Valve opening and closing timing measurement: Place the dial indicator probe against the valve spring seat 7 plane, slowly rotate the crankshaft using the crankshaft adjustment plate 12, and monitor the dial indicator pointer. When the pointer deviates by ≥0.01mm, read the value B on the dial 8 and calculate the valve opening timing phase θopen=BA; record the dial angle B1 when the valve lift is 0.05mm, 0.55mm, and 1.05mm, and the dial angle B2 when the valve lift is 1.05mm, 0.55mm, and 0.05mm during the valve closing process. Obtain the opening and closing timing phases of the corresponding lifts through the differences between B1 and A, and between B2 and A.
[0035] Furthermore, in step four, the difference between the actual value measured and the theoretical phase at the opening and closing times corresponding to each lift is the phase deviation.
[0036] I. Equipment Assembly:
[0037] Prepare the following accessories: measuring rod fixture 1, measuring rod, dial indicator, dial 8, crankshaft adapter plate 12, rigid tappet and bolts, etc. Ensure that the dimensions of each component meet the fitting requirements. The measuring rod should be precisely fitted with the measuring rod hole 2 of the measuring rod fixture 1. The center hole 9 and pin hole 11 of the dial 8 should be adapted to the corresponding structure of the crankshaft. The adapter plate bolt hole 14 and pin hole 15 of the crankshaft adapter plate 12 should be aligned with the corresponding hole positions of the dial 8.
[0038] Establishing the initial measurement state: For engines without a timing system, first assemble the cylinder head system, cylinder block, and crankshaft system components, install the rigid tappets, and then complete the timing system assembly; for engines that have already been assembled, remove the peripheral components and timing system, replace the original hydraulic tappets with rigid tappets, and then restore the timing system to ensure that the engine is in a measurable state.
[0039] II. Top dead center measurement operation:
[0040] Select the cylinder to be measured, align the spark plug mating thread 3 of the measuring rod fixture 1 with the spark plug thread hole 6 of the cylinder head 4, slowly screw it into the spark plug hole 5 and tighten it to ensure that the measuring rod fixture 1 and the cylinder head 4 are stably fitted without loosening.
[0041] Insert the probe into the probe hole 2 of the probe fixture 1 until the lower end of the probe touches the top of the piston, ensuring that the probe is in full contact with the top of the piston.
[0042] Set up a dial indicator on the top of the measuring rod, adjust the position of the dial indicator so that the probe of the dial indicator is perpendicular to the top of the measuring rod and the dial indicator is within a suitable range, and set it to zero for later use.
[0043] Slowly rotate the crankshaft, and the probe moves up and down with the piston. Observe the change of the dial indicator pointer. When the pointer reaches its maximum value and stops rising, this position is the limit position of the probe's rise, which corresponds to the top dead center position of the piston. Record the dial indicator reading at this time to confirm the top dead center state.
[0044] III. Installation and Operation of the Dial and Turning Car Adapter:
[0045] Align the center hole 9 of the dial 8 with the crankshaft stop on the rear flange of the crankshaft, ensuring that the dial pin hole 11 of the dial 8 mates with the crankshaft pin for positioning, thus ensuring that the dial 8 rotates coaxially with the crankshaft. Secure the dial 8 to the rear flange of the crankshaft by passing bolts through the dial bolt holes 10, and tighten the bolts to ensure that the dial 8 is firmly installed without any wobbling. Align the pin hole 15 of the turning gear adapter 12 with the pin hole 11 of the dial 8, and align the bolt hole 14 of the adapter 12 with the bolt hole 10 of the dial 8. Secure the turning gear adapter 12 to the dial 8 with bolts, ensuring that the turning gear adapter 12 rotates synchronously with the dial 8.
[0046] Set a reference point on the engine block 16 or other fixed parts, or install a pointer so that the pointer points to the scale surface of the dial 8. Adjust the position of the pointer to ensure that the pointer clearly points to the scale of the dial 8 for easy reading of the value. Use the scale value pointed to by the pointer at this time as the reference angle value A corresponding to the top dead center position of the cylinder, and record the reference angle value A.
[0047] IV. Valve opening and closing timing measurement procedure:
[0048] Remove the dial indicator used for top dead center measurement. Move the dial indicator above the intake or exhaust valve to be measured. Adjust the position of the dial indicator so that the probe is perpendicular to the valve spring seat 7 plane, ensuring full contact between the probe and the spring seat plane, and that the dial indicator range is appropriate. Zero the dial indicator for later use. Using the crankshaft cranking cap 13 on the crankshaft cranking adapter 12, slowly and evenly crank the crankshaft while closely monitoring the dial indicator pointer changes.
[0049] When the pointer offset of the dial indicator is ≥0.01mm, it is determined that the valve begins to disengage from the seated state and enter the opening stage. At this time, the value B pointed to by the pointer on the dial 8 is read. According to the formula θopen=BA, the valve opening time phase is calculated. This phase indicates that the valve opens at BA° after the top dead center.
[0050] Continue to slowly rotate the crankshaft, and read the angle value B1 corresponding to the scale 8 when the valve lift reaches 0.05mm, 0.55mm, and 1.05mm respectively, and record them one by one; continue to rotate the crankshaft until the valve begins to close, and read the angle value B2 corresponding to the scale 8 when the valve lift drops to 1.05mm, 0.55mm, and 0.05mm respectively, and record them one by one as well.
[0051] Calculate the difference between the opening phase B1 and A and the closing phase B2 and A for each lift. Based on these data, plot the complete valve opening and closing. Compare this data with the engine's theoretical valve timing. The difference between the two is the valve timing deviation, thus completing the valve timing measurement.
[0052] Following the steps above, perform the intake and exhaust valve timing measurements for the other cylinders in sequence to ensure the integrity and accuracy of the measurement data.
[0053] This invention enables high-precision, high-repeatability, low-cost, and interference-resistant static measurement of engine valve timing, making it particularly suitable for final inspection on production lines, R&D verification, and maintenance scenarios.
[0054] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A purely mechanical based engine valve timing measurement device, characterized by: The system includes a measuring rod fixture (1), a measuring rod, a dial indicator, a dial (8), a pointer, and a cranking adapter plate (12). The measuring rod fixture (1) is set inside the spark plug hole (5) of the cylinder head (4). The measuring rod is installed on the measuring rod fixture (1), and its upper and lower ends contact the dial indicator and the piston top respectively to form a "piston-measuring rod-dial indicator" sensing chain mechanism. The dial (8) is installed on the rear flange surface of the crankshaft. The cranking adapter plate (12) is installed on the dial (8). The pointer is set and used in conjunction with the dial (8) to point to the dial (8) to read the scale value and determine the reference angle.
2. The engine valve timing measurement device based on pure mechanics according to claim 1, characterized in that: The measuring rod tool (1) is provided with a measuring rod hole (2) and a spark plug mating thread (3). The spark plug mating thread (3) is used to engage with the spark plug thread hole (6) of the cylinder head (4). The measuring rod is inserted into the measuring rod hole (2), with one end used to abut against the piston top and the other end used to abut against the dial indicator probe.
3. The engine valve timing measurement device based on pure mechanics according to claim 1, characterized in that: The dial (8) is provided with a dial center hole (9), a dial bolt hole (10) and a dial pin hole (11). The dial center hole (9) is used to cooperate with the crankshaft stop, the dial pin hole (11) is used to cooperate with the crankshaft pin, and the bolt hole (10) is used to fix the dial (8) to the crankshaft rear flange surface by bolts. The turning gear adapter (12) is provided with a turning gear cap (13), an adapter bolt hole (14) and an adapter pin hole (15). The turning gear adapter (12) is installed on the dial (8) through the adapter bolt hole (14) and bolts, and the adapter pin hole (15) is set and used in conjunction with the dial pin hole (11).
4. A method for measuring engine valve timing phase using the purely mechanical engine valve timing phase measuring device according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Establish initial measurement conditions: Assemble the cylinder head system, cylinder block, and crankshaft system components, install the rigid tappets, and then assemble the timing system; if it is a complete machine, remove the peripheral components and timing system, replace the hydraulic tappets with rigid tappets, and then restore the timing system; Step 2: Top dead center measurement: Screw the test rod tool (1) into the spark plug thread hole (6) of the cylinder head (4) through the spark plug mating thread (3). The test rod passes through the test rod hole (2) and abuts against the piston top. The dial indicator probe abuts against the top of the test rod. Rotate the crankshaft and determine the upper limit position of the test rod by the dial indicator reading, which is the piston top dead center. Step 3: Installation of dial (8) and crankshaft adapter plate (12): Connect the dial (8) to the crankshaft through the dial center hole (9) and dial pin hole (11), and fix it to the rear flange of the crankshaft through the dial bolt hole (10); install the crankshaft adapter plate (12) on the dial (8) through the adapter plate bolt hole (14) and adapter plate pin hole (15), set the pointer to point to the dial (8), and determine the reference angle value A corresponding to the top dead center; Step 4: Valve opening and closing time measurement: Place the dial indicator probe against the valve spring seat (7) plane, slowly rotate the crankshaft through the cranking adapter (12), monitor the dial indicator pointer, when the pointer deviates by ≥0.01mm, read the value B on the dial (8), and calculate the valve opening time phase θopen=BA; record the dial angle B1 when the valve lift is 0.05mm, 0.55mm, and 1.05mm respectively, and the dial angle B2 when the valve lift is 1.05mm, 0.55mm, and 0.05mm during the valve closing process. Obtain the opening and closing time phases of the corresponding lifts through the differences between B1 and A, and between B2 and A.
5. The engine valve timing phase measurement method according to claim 4, characterized in that: In step four, the difference between the actual value measured at the opening and closing times corresponding to each lift and the theoretical phase is the phase deviation.