# New Actuation Control for Hybrid Electromagnetic Valve Train
## 5 Results  
Firstly, it is required to explore whether the improved magnetic circuit will cause the demagnetization of the permanent magnet's magnetic force. Hence, a simulation analysis was carried out for an in-depth understanding of the demagnetization effect on the magnets when the EM valve is energized with the releasing pulse and catching pulse. As shown in Figure 10a, the lower circular cross-section of the simulated permanent magnets 1 and 2 is located where the permanent magnets are attached to the armature. When the attraction current is applied, the average magnetic flux density B of the cross-section and the average magnetic field intensity H generated are shown in the BH relationship diagram, as shown in Figure 10b, and are compared with the demagnetization curve table of the permanent magnet N35 neodymium iron magnet used in the EM valve, as shown in Figure 10c. The cross-sections of permanent magnets 1 to 4 are all within the working range of BH, which will not cause the demagnetization of the permanent magnet N35. This verifies the durability of the improved EM valve permanent magnet. Next, the maximum attraction force, when the releasing pulse or catching pulse is applied, is measured. Through the experimental test results, it is known that the EM valve has different attraction forces under the different currents of the permanent magnet, release, and attraction. Figure 11 shows the experimental results of the maximum attraction force during the releasing pulse catching pulse. It can be seen that when the EM valve is supplied with a current of 3A, the release force is close to zero, which is very different from the attraction force of 549.2 N. This means that the larger the spring coefficient of elasticity is that can be used, the faster the armature moves, and the higher the engine speed is that can be matched. Lastly, the armature release and attraction timing are measured with the EM valve test. As shown in Figure 12, the release pulse given at Ts1 is 1000 ms. The required time \(\Delta\)tI is 10 ms. The armature releases and leaves the lower vertex. After the armature is released, Ts2 is 1035 ms. When the time required to pass the suction pulse \(\Delta\)t2 is 10 ms, the output pulse is stopped, and the armature reaches the upper peak. When Ts3 is 1200 ms, the release pulse is passed, and the required time \(\Delta\)t3 is 10 ms for the armature to leave the upper peak. When Ts4 is 1235 ms after the armature is released, the time required to pass the attraction pulse \(\Delta\)t4 is 10 ms, and then the output pulse is stopped. The armature reaches the lower peak. The test is completed, and the results are shown in Figure 13. The fastest speed of the air valve is 300 rpm. According to the above electronic valve test experiment, it is found that the time required for the armature of the electronic valve to go from the top to the bottom or from the bottom to the top of the armature are the same, at 104 ms. This time does not reach the idling speed of the internal combustion engine. In the future, it will be important to reduce this time by improving the spring coefficient and replacing the permanent magnet with a higher magnetic force. However, the amperage of the input pulse also needs to increase to raise the adsorption force of the electronic valve to match the high-stiffness springs. Figure 10: (a) Selected cross-section of the permanent magnets; (**b**) B–H bar charts for each section of permanent magnet; (**c**) verification of demagnetization curve. Figure 11: Experimental test results of maximum attraction force during the releasing pulse and catching pulse. Figure 12: Experimental test results for the proposed PMEM valve. Figure 13: Continuous measurement of EM valve. At present, the guided composite electronic valve has not been actually used in the engine, but if it is in the future then this study can be said to be a very outstanding contribution, because this paper demonstrates the permanent magnet electronic valve under long-term operation without demagnetization.