High pressure natural gas stop valve drive circuit diagram

The picture shows the drive circuit of the high-pressure natural gas shut-off valve. Device 01 is a solid-state relay. When the engine is working in a dual-fuel state, the fuel conversion mechanism works, and the logic judgment part issues instructions to make Y4 = 1, which is high level. After U2 (7404, inverter), the electric heating UB at point B is low level. , the potential UA at point A on the surface is higher than that at point B. At this time, the input end of the solid-state relay is turned on and the output end is also turned on. Once the output terminal CD is connected, the rated operating voltage of 12V will be applied to both ends of the solenoid valve HPVALVE, causing the high-pressure natural gas valve in front of the pressure reducer to open, and the natural gas will enter the engine through decompression. When the instruction issued by the logic judgment part causes the solenoid valve to close, Y4=0, after passing through the inverter, B is high level, UA=UB, there is no current passing through the input end of the solid-state relay, and the output end is not conducting, so the solenoid valve It returns to the normally closed state under the action of spring force.