The difference and function between double H valve and single H valve in gearbox!

1, the double H valve is mainly used for high and low gear shifting and basic gear shifting with auxiliary box, and the single H valve is used for basic gear shifting without auxiliary box.

2. The single H valve is actually a one-way valve, and the airflow can shift gears between 1.2.3.4 gears by pushing the shift fork. The double H valve is a two-way valve, one of which realizes 1.2.3.4 shift, and the other realizes high-speed 5.6.7.8 shift through the auxiliary box.

3. The main box and the transfer box are separated. The shift action of the main box and the shift action of the auxiliary box need to be carried out at the same time, and the combination is high gear. And this requires a two-way air valve to achieve. Without the H valve, it is impossible to control gear shifting, that is, the gas path is always open, and the shift fork will always be in one of the gears.

Extended data:

principle of operation

Working principle of 1 and AT transmission system

(1) The structure of AT transmission system is quite different from that of manual transmission.

(2) The manual gear is mainly composed of gears and shafts, which generate speed change and torque through different gear combinations; AT transmission system is composed of hydraulic torque converter, planetary gear and hydraulic control system, and variable speed and torque are realized through hydraulic transmission and gear combination.

(3) Among them, the hydraulic torque converter is the most distinctive part of AT, which consists of pump wheel, turbine and guide wheel. It directly inputs engine power, transmits torque and has clutch function.

(4) The pump wheel and turbine are a pair of working combinations, just like two fans placed opposite each other. The wind of one fan will drive the blades of another fan to rotate, and the wind will become the medium of kinetic energy transfer.

(5) If liquid is used instead of air as the medium to transfer kinetic energy, the pump wheel drives the turbine to rotate through the liquid, and then a guide wheel is added between the pump wheel and the turbine, so that the speed difference between the pump wheel and the turbine can be realized through the reaction force, and the variable speed and torque can be realized.

(6) Because the range of automatic speed change and torque change of hydraulic torque converter is not large enough, in order to improve efficiency, several rows of planetary gears are connected in series behind the turbine, and the hydraulic control system will automatically control the planetary gears with the change of engine work, thus realizing automatic speed change and torque change.

(7) The automatic shift of auxiliary mechanism can't meet all kinds of needs in driving, such as parking, backing up, etc. Therefore, there are intervention devices marked with P (parking), R (rear position), N (neutral position) and D (forward position), and additional gears of "2" and "1" are provided in the forward carry.

(8) Because its transmission is divided into several speed ratio sections, it is stepless only in the specified speed section, so AT is actually an automatic transmission between step and stepless.

2. There are usually two types of hydraulic automatic transmission: one is transverse hydraulic automatic transmission; The other is a longitudinal hydraulic automatic transmission.

(1) Electronic control of hydraulic automatic transmission The power transmission control module (PCM) receives the electrical signals input by various sensors on the automobile, and processes the information according to the working conditions of the automobile to determine the working state of the hydraulic automatic transmission.

(2) According to these working conditions, the power transmission control module sends instructions to the actuator to realize the following functions: transmission upshift and downshift; Generally, a pair of electronic shift solenoid valves are operated to switch between on/off states;

(3) The oil pressure in the pipeline is adjusted by electronically controlled pressure control solenoid valve (PCS); The torque converter clutch (TCC) is used to control the engagement and disengagement time of the solenoid valve.

3. The automatic transmission mainly controls the upshift and downshift according to the speed sensor (VSS), throttle position sensor (17 throttle position sensor (TPS) and the degree of the driver's stepping on the accelerator pedal.