The working medium of the bus brake system, air suspension, passenger door switch, etc. is compressed air, and the air compressor on the bus engine provides compressed air for these air-consuming equipment. The water in the compressed air not only rusts and damages the components of the gas equipment, but also causes vehicle failures and even affects the vehicle due to the freezing of water in winter to block the air passage Drive safely. The function of the air dryer installed after the air compressor is to absorb the moisture in the compressed air and provide the compressed air as dry as possible for the gas equipment.
The structure of the air dryer for auto is shown in the figure below
k. Drying filter j. Spiral passage a. Desiccant I. Inclined hole g. Diaphragm assembly of pressure regulating valve n. Valve d. Piston e. Exhaust valve
The work of the auto air dryer is that the compressed air enters chamber A from port 1, passes through the drying filter k and the spiral passage j, and then reaches chamber C through desiccant α, and part of the dry air in chamber C flows into the regeneration air storage tank through port 22. The other part flows into port 21 through the one-way valve to supply air to the follow-up system, and at the same time, part of the air flows from inclined hole I into cavity D, acting on the diaphragm assembly g of the pressure regulating valve. When the system air pressure exceeds the spring preload pressure of the pressure regulating valve, the valve n opens, and the air enters the B chamber from the D chamber, pushing the piston d to move down to open the exhaust valve e, and the air compressor is unloaded. When the air compressor is unloaded, the air in the regenerative air storage tank flows in reverse and is discharged from port 3. When the reverse blowing air passes through the desiccant, the moisture is taken away to realize the activation and regeneration of the desiccant.
The air pressure of the system decreases with the exhaust unloading and subsequent air consumption, the valve n is closed under the action of the spring, the air in chamber B is discharged into the atmosphere through the small hole of the valve seat of the pressure regulating valve, the exhaust valve e is closed, and enters the next air supply unloading cycle. Repeatedly, the air pressure value at 21 ports is always kept within a certain range, realizing automatic pressure regulation.
Through the comprehensive analysis of the structure and principle of the air dryer from the above content, it can be seen that its automatic pressure regulation performance is very important to the realization of its overall function.
