Research Of Electronic Detector For The Cylinder Head Valve Seat Run-out

The cylinder head is an important component of the engine valve train and fuel supply system. As the key part of the cylinder head, the processing precision of the valve seat and valve guide hole affects the gastightness, the fuel consumption, the durability, the effective torque output power and other performance indicators directly. For the parameters test of the valve seat, the relative run-out of conical surface of the valve seat to the centerline of guide hole is particularly important. The width of the cone seal is very narrow, and the valve guide hole is very deep and its diameter is too small, so it is difficult to be measured with common measurement methods, and the detection efficiency is very low. It is necessary to develop a kind of simple equipment which has high efficiency, strong reliability and high precision to meet the requirements of users.Firstly, the paper designs the total solution and sets up the mathematics model of the measurement system including real-time equation and non-real-time equation on the basis of the research of the run-out measurement principle of the cylinder head valve seat. Secondly, the paper studies the signal processing system of inductive displacement sensor on the gauge including waveform generation circuit, amplifier circuit, phase sensitive detection circuit and low pass filter circuit. Lastly, taking ADμC843 MCU as the core, the project uses H-limited unipolar PWM driving system to control the rotation system.In the process of detector's rotation, all the measurement points scan a lap around the guide hole centerline and the conical surface of the valve seat. At the same time all the sensor signals are sampled by the data acquisition system composed of computer and DAQ. Then the computer deals with the sampled data and calculates the result according to the equation which the software pre-sets. The paper also introduces the theory of statistical measurement. The technologists can analyze the process with the (x|-)-R charts.Finally, the performance test for the gauge has been done. The test data shows that the detector has good stability, good repeatability and high detection accuracy. The detector meets the needs of the fast-paced and high-precision detection for the production line.