In urban transportation, buses are an important tool for public transportation, and bus air conditioners are key equipment for creating a comfortable riding environment for passengers. Next, let’s learn about bus air conditioners.
Bus air conditioners can adjust the temperature inside the bus, filter the air, remove dust, odors and bacteria, provide passengers with a fresh and healthy environment, and greatly improve the comfort of travel. Whether it is a hot summer or a cold winter, it can protect passengers from the bad weather outside.
1. Working principle
Bus air conditioning refrigeration is based on a vapor compression refrigeration cycle. The compressor compresses the low-temperature and low-pressure refrigerant gas into a high-temperature and high-pressure gas, which then enters the condenser for heat dissipation and liquefaction, and then enters the evaporator after being depressurized by the throttling device, absorbing the heat of the car to realize the refrigeration cycle. Heating mostly relies on electric heating or engine waste heat.
2. Common faults and solutions
Refrigeration related
Poor refrigeration effect: It may be refrigerant leakage, compressor failure, or poor condenser heat dissipation. Refrigerant leakage requires a halogen leak detector to find the leak point, repair and replenish; compressor failure requires inspection of pistons, valves and other components and repair or replacement; poor condenser heat dissipation can be cleaned with a high-pressure water gun and a detergent.
No cooling: In addition to the above reasons, electromagnetic clutch failure and expansion valve blockage can also cause it. The electromagnetic clutch needs to be checked and replaced, and the expansion valve needs to be cleaned or replaced.
Heating related
No heating or poor heating effect: If the engine is heated by residual heat, it may be a failure of the engine cooling system, such as insufficient coolant or water pump failure. It is necessary to check and replenish coolant, repair or replace the water pump; if it is heated by electric heating, it may be a damaged heating element, which needs to be replaced and the circuit checked.
Uneven heating: It is mostly caused by improper adjustment of the air duct damper or blockage of the air outlet. Manually adjust the damper and clean up the debris.
Noise problem
The noise mostly comes from the compressor and fan. The high noise of the compressor may be caused by wear of internal parts, which needs to be checked and replaced; the high noise of the fan may be caused by loose or unbalanced blades. Tighten and adjust the blades, add lubricating oil to reduce noise, and foreign matter in the air duct will also cause noise. Use the air duct cleaning brush to clean it.
Electrical system failure
Unable to start: It may be a power line failure, such as a blown fuse, a short circuit or a break in the line. It is necessary to check and replace the fuse, and check and repair the line; it may also be a control circuit board failure. Professionals will detect and replace damaged components.
Temperature control failure: mostly due to temperature sensor failure, need to replace new sensor.
Drainage system failure
Water leakage in the car is mostly due to blockage or damage of drainage pipes, need to clear the blockage, and replace the pipes if damaged.
3. Daily maintenance points
Regular cleaning: deep clean the evaporator and condenser every quarter, clean the filter every month to prevent dust accumulation from affecting performance.
Check the refrigerant: regularly check the pressure and liquid level, find out the deficiency in time to check for leaks and replenish, and pay attention to the refrigerant models cannot be mixed.
Maintain the compressor and fan: regularly check the operation, add lubricating oil, and repair in time if there is any abnormality.
