Engine cylinder head valve opening / closing timing relative to crank angle measurement system

Abstract

A kind of engine cylinder cover valve opening and closing time relative crank angle measurement system belongs to engine detection technical field.Sensor fixed tooling has installation hole one, installation hole two, installation hole three, threaded hole one, threaded hole two, threaded hole three, tooling fixed hole one, tooling fixed hole two and tooling fixed hole three, installation hole one is installed into air inlet displacement sensor, installation hole two is installed into exhaust displacement sensor, installation hole three is installed into piston top dead center displacement sensor, incremental encoder is connected with engine pulley, air inlet displacement sensor, exhaust displacement sensor, piston top dead center displacement sensor signal is accessed PLC controller, incremental encoder output signal is accessed PLC controller, PLC controller passes data to host computer measurement system.The utility model is in cooperation with the design of each component, high-precision, automatic measurement to engine valve opening and closing time relative crank angle is realized, and it is convenient for data management and analysis, provides effective support for engine test.

Description

Technical Field

[0001] This utility model belongs to the field of engine testing technology, specifically a system for measuring the angle of the engine cylinder head valve opening and closing relative to the crankshaft. Background Technology

[0002] Currently, there are design values ​​for the opening and closing angles of engine cylinder head valves relative to the crankshaft, but the actual values ​​under actual engine rotation have not been measured. Now, a measurement system is invented to measure the angle of engine cylinder head valve opening and closing relative to crankshaft rotation, and to actually measure the crankshaft angle position corresponding to the actual opening and closing of engine cylinder head valves. Summary of the Invention

[0003] To address the problems existing in the background art, this utility model provides a system for measuring the angle of the engine cylinder head valve opening and closing relative to the crankshaft.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an engine cylinder head valve opening and closing time relative crankshaft angle measurement system, including a displacement sensor fixing fixture, an intake displacement sensor, an exhaust displacement sensor, a piston top dead center displacement sensor, an incremental encoder, a PLC controller and a host computer measurement system;

[0005] The sensor mounting fixture is provided with mounting hole 1, mounting hole 2, mounting hole 3, threaded hole 1, threaded hole 2, threaded hole 3, fixture fixing hole 1, fixture fixing hole 2, and fixture fixing hole 3. An intake displacement sensor is installed in mounting hole 1 and secured with a bolt in threaded hole 1. An exhaust displacement sensor is installed in mounting hole 2 and secured with a bolt in threaded hole 2. A piston top dead center displacement sensor is installed in mounting hole 3 and secured with a bolt in threaded hole 3. The fixture fixing holes 1, 2, and 3 are used to install the displacement sensor mounting fixture to the engine cylinder head. The incremental encoder is coaxially connected to the engine pulley via a screw mounting hole and is used to measure the crankshaft angle. The 4-20mA analog signals output by the intake displacement sensor, exhaust displacement sensor, and piston top dead center displacement sensor are connected to the PLC controller. The pulse signal output by the incremental encoder is also connected to the PLC controller. The PLC controller transmits the processed displacement data and crankshaft angle data to the host computer measurement system. The host computer measurement system is used to display and store the displacement data and crankshaft angle data, and to calculate the valve opening and closing times based on the data.

[0006] The incremental encoder mounting fixture includes a mounting component connected to the flange of the incremental encoder and a connecting component fixed to the engine. The mounting component and the connecting component are fixedly connected, and the axis of the mounting component is coaxial with the crankshaft axis.

[0007] The PLC controller integrates an S_ITR module, which converts 4-20mA analog signals into displacement values, and is equipped with a high-speed pulse input channel, which converts the pulse signals output by the incremental encoder into crankshaft rotation angle values.

[0008] The host computer measurement system is based on Visual Studio, communicates with the PLC controller through the S7.Net communication protocol, and stores displacement data, crankshaft angle data, and valve opening and closing time data through an SQL database.

[0009] Compared with the prior art, the beneficial effects of this utility model are:

[0010] 1. Achieve high-precision measurement: By using a displacement sensor and an incremental encoder, combined with the signal conversion and processing functions of the PLC module, the crankshaft angle corresponding to the valve opening and closing moments can be accurately obtained.

[0011] 2. Ensure installation coaxiality and system stability: The incremental encoder fixing fixture ensures that the encoder and crankshaft are installed coaxially, avoiding angle measurement errors caused by installation deviations and ensuring the stability of system operation.

[0012] 3. Automated data processing and valve timing determination: The PLC controller synchronously collects signals and marks data timing through rapid cyclic scanning. The host computer presets the displacement threshold and signal change rate threshold for valve opening and closing, which can automatically mark the crankshaft angle at the valve action time, reducing manual intervention.

[0013] 4. Facilitates data display, storage, and analysis: After communication between the host computer and the PLC, the displacement and crankshaft angle data are displayed in real time, and the corresponding relationship is dynamically presented in curves and charts. At the same time, various types of data are stored in the database for easy subsequent analysis and optimization.

[0014] 5. Improved installation convenience and benchmark consistency: The displacement sensor mounting fixture can be adjusted and installed according to the position of the engine cylinder head screw holes, and the crankshaft angle reference point is calibrated through the piston top dead center displacement sensor to ensure the consistency of the angle measurement benchmark under different operating conditions.

[0015] In summary, this utility model, through the collaborative design of its components, achieves high-precision, automated measurement of the angle between the engine valve opening and closing moments and the crankshaft, and facilitates data management and analysis, providing effective support for engine-related testing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0017] Figure 2 This is a top view of the present invention. Detailed Implementation

[0018] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0019] This embodiment describes an engine cylinder head valve opening and closing time relative crankshaft angle measurement system, including a displacement sensor fixing fixture, an intake displacement sensor, an exhaust displacement sensor, a piston top dead center displacement sensor, an incremental encoder 10, a PLC controller, and a host computer measurement system.

[0020] The sensor mounting fixture is provided with mounting hole 1, mounting hole 2, mounting hole 3, threaded hole 4, threaded hole 5, threaded hole 6, fixture fixing hole 7, fixture fixing hole 8, and fixture fixing hole 9. An intake displacement sensor is installed in mounting hole 1 and secured with a bolt in threaded hole 4. An exhaust displacement sensor is installed in mounting hole 2 and secured with a bolt in threaded hole 5. A piston top dead center displacement sensor is installed in mounting hole 3. (Intake displacement sensor, exhaust displacement sensor, piston top dead center) The displacement sensor preferably has a measurement accuracy of ±0.01mm and an output signal of 4-20mA analog quantity (corresponding to a displacement range of 0-20mm). It is fastened by bolts through threaded hole 6. Fixture fixing holes 7, 8, and 9 are used to install the displacement sensor fixing fixture to the screw mounting holes of the engine cylinder head. The incremental encoder 10 is coaxially connected to the engine pulley through the incremental encoder fixing fixture and is used to measure the crankshaft angle (the incremental encoder 10 preferably has a resolution of 1024 pulses / revolution). The 4-20mA analog signals output by the intake displacement sensor, exhaust displacement sensor, and piston top dead center displacement sensor are connected to the PLC controller. The pulse signal output by the incremental encoder 10 is connected to the PLC controller. The PLC controller transmits the processed displacement data and crankshaft angle data to the host computer measurement system. The host computer measurement system is used to display and store the displacement data and crankshaft angle data, and calculate the valve opening and closing time based on the data.

[0021] The incremental encoder fixing fixture includes a mounting part connected to the flange of the incremental encoder 10 and a connecting part fixed to the engine. The mounting part and the connecting part are fixedly connected (preferably fixed by bolts, and the coaxiality error between the axis of the mounting part and the crankshaft axis is ≤0.05mm), and the axis of the mounting part is coaxial with the crankshaft axis.

[0022] The PLC controller integrates an S_ITR module, which converts 4-20mA analog signals into displacement values, and is equipped with a high-speed pulse input channel, which converts the pulse signals output by the incremental encoder into crankshaft rotation angle values.

[0023] The host computer measurement system is based on Visual Studio as an existing technology and communicates with the PLC controller through the S7.Net communication protocol (preferred preset valve opening displacement threshold is 0.5mm, closing displacement threshold is 0.3mm, and displacement signal change rate threshold is 0.1mm / ms). It also stores displacement data, crankshaft angle data, and valve opening / closing time data through an SQL database.

[0024] When using this utility model, the intake displacement sensor and exhaust displacement sensor are respectively installed in mounting holes 1 and 2 of the fixed fixture, and fastened with bolts through threaded holes 4 and 5. Their probes directly contact the top of the valve stem to monitor the axial displacement of the valve in real time. The piston top dead center displacement sensor is installed in mounting hole 3 and fixed through threaded hole 6. The probe is aligned with the top surface of the piston to calibrate the piston top dead center position. All three displacement sensors output 4-20mA analog signals, corresponding to a displacement range of 0-20mm. The incremental encoder 10 is coaxially connected to the engine pulley through a special fixed fixture (the axis of the fixture mounting part is coaxial with the crankshaft axis). When the pulley rotates, it drives the encoder to rotate. The encoder outputs a fixed number of pulse signals for each revolution. The pulse frequency is proportional to the crankshaft speed. The PLC controller is preferably a Siemens PLC, which integrates an S_ITR module. After receiving the 4-20mA signals output by the displacement sensors, it converts them using a linear conversion formula. The current signal is converted into an actual displacement value of 0-20mm, and the valve lift and piston position are displayed in real time. At the same time, the PLC controller acquires the pulse signal of the incremental encoder through the high-speed pulse input channel and calculates the crankshaft angle according to the encoder resolution (e.g., pulses per revolution N). For example, if the encoder outputs 1024 pulses per revolution, each pulse corresponds to a 0.35° crankshaft angle. The host computer, developed using Visual Studio, establishes an Ethernet connection with the PLC controller via the S7.Net communication protocol. It reads the displacement data (valve lift, piston position) and crankshaft angle data processed by the PLC controller in real time, dynamically displaying the correspondence between the three in the form of a graph. The system presets displacement thresholds for valve opening / closing (e.g., intake valve opening threshold of 0.5mm). When the displacement sensor data exceeds or falls below the threshold, it automatically marks the crankshaft angle value at that moment, combined with the synchronously acquired crankshaft angle data. Simultaneously, it monitors the rate of change of the displacement signal in real time. When the rate of change exceeds a set threshold (e.g., 0.1mm / ms), it is determined to be the valve action start point, and the crankshaft angle value output by the PLC controller at that moment is recorded as the valve opening / closing value. For the corresponding closed angle, the host computer stores three types of data through an SQL database: raw sensor signals (4-20mA current value, pulse count, and real-time displacement-angle curve sampling frequency ≥100Hz), and calculated valve opening / closing time data (including angle value, timestamp, and operating parameters). Before starting the engine, the piston is manually cranked to the top dead center position. At this time, the piston top dead center displacement sensor outputs the maximum value, and the PLC controller marks this point as the crankshaft angle 0° reference point to ensure a unified angle measurement benchmark. The PLC controller uses a cyclic scanning method with a scanning period ≤10ms to synchronously acquire signals and marks the data acquisition time with an internal clock stamp to ensure the consistency of the timestamps of displacement and angle data and avoid measurement delay errors.

[0025] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this 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 this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A system for measuring the angle of engine cylinder head valve opening / closing relative to the crankshaft, characterized in that: It includes a displacement sensor fixture, an intake displacement sensor, an exhaust displacement sensor, a piston top dead center displacement sensor, an incremental encoder (10), a PLC controller, and a host computer measurement system; The sensor fixing fixture is provided with mounting holes 1 (1), 2 (2), 3 (3), 4 (4), 5 (5), 6 (6), 7 (7), 8 (8), and 9 (9). An intake displacement sensor is installed in mounting hole 1 (1) and secured with bolts in 4 (4). An exhaust displacement sensor is installed in mounting hole 2 (2) and secured with bolts in 5 (5). A piston top dead center displacement sensor is installed in mounting hole 3 (3) and secured with bolts in 6 (6). The fixture fixing holes 1 (7), 2 (8), and 9 are also provided. 9) The screw mounting holes for mounting the displacement sensor fixture to the engine cylinder head are used. The incremental encoder (10) is coaxially connected to the engine pulley through the incremental encoder fixture and is used to measure the crankshaft angle. The 4-20mA analog signals output by the intake displacement sensor, exhaust displacement sensor and piston top dead center displacement sensor are connected to the PLC controller. The pulse signal output by the incremental encoder (10) is connected to the PLC controller. The PLC controller transmits the processed displacement data and crankshaft angle data to the host computer measurement system. The host computer measurement system is used to display and store the displacement data and crankshaft angle data, and calculate the valve opening and closing time based on the data.

2. The engine cylinder head valve opening / closing angle measurement system relative to the crankshaft according to claim 1, characterized in that: The incremental encoder fixing fixture includes a mounting part connected to the flange of the incremental encoder (10) and a connecting part fixed to the engine. The mounting part and the connecting part are fixedly connected, and the axis of the mounting part is coaxial with the crankshaft axis.

3. The engine cylinder head valve opening / closing angle measurement system relative to the crankshaft according to claim 1, characterized in that: The PLC controller integrates an S_ITR module, which converts 4-20mA analog signals into displacement values, and is equipped with a high-speed pulse input channel, which converts the pulse signals output by the incremental encoder into crankshaft rotation angle values.

4. The engine cylinder head valve opening / closing angle measurement system relative to the crankshaft according to claim 1, characterized in that: The host computer measurement system is based on Visual Studio, communicates with the PLC controller through the S7.Net communication protocol, and stores displacement data, crankshaft angle data, and valve opening and closing time data through an SQL database.

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