As the temperature outside becomes higher in the summer, and the drivers are travelling outside the north and south, and the use of vehicle-borne air-conditioning is essential, air-conditioning failures are very common during this hot season, and today's card shares knowledge of some air-conditioning systems and helps mechanics to cope with the associated problems。
The air conditioners for commercial vehicles consist of three main components: compressors, condensers, evapotors, expansion valves, liquid dryers, pipes, condensers, blowers, heat packs, etc. So how do we check the performance of the units that judge the refrigeration system
1. Check compressors: connect pressure meters to compressors, with high and low pressure hoses interfaced with compressors vents and inhalations, respectively. Activate diesel engines, keep turn speeds at 1500 ~2000r/min, start cooling systems, fans at maximum speed, air conditioning switches at the strongest, check for metal taps in compressors, leaks in oil seals and other connections. In addition, pressure gauge readings should be observed, with a low pressure side of approximately 150 ~200 kpa and a high pressure side of about 1,400 ~ 1500 kpa, indicating that the refrigeration system is normal, otherwise the compressor should be overhauled。
2. Examination of condensers, evaporaters, liquid storage tubes: an external inspection shall be conducted first to check whether the dispersive sheet has been damaged, blocked, the interface and the pipe damaged or leaked. In addition, it is measured with a bit of thermometer. The temperature of the condenser entrance tube shall be 70 °c and the temperature of the exit tube shall be around 50 °c when the air conditioner unit is working. The temperature on the evaporation unit surface is as low as possible without frost. The temperature of the tank shall normally be around 50 °c and, at the time of the inspection, the upper and lower temperature of the tank is measured and, if inconsistent, indicates a grid congestion of the tank。
3. Checking expansion valves: by observing the surface state of the evapoperator. If the evaporation unit surface is frosted, the first is to indicate that the evaporation unit surface temperature control is not working. Second is a description of the failure of the opening of the swelling valve or of the leakage or failure of the sensor。
Let's go.
Air-conditioning in vehicles is a relatively independent system, and the overhaul of the air-conditioning system requires consideration of the relationship of the system itself. The big card below looks at both the lines and the sound。
How do we fix the air conditioner electrical circuit failure
In case of failure, the following three aspects must be examined:
1. If the clutch does not inhale or the motor is not rotated, the component's power supply should first be traced by reference to the ac circuit, and the voltage checked for normality and melting. If directly connected to the battery, check if the component is loose。
2. If none of the above checks are in question, the failure occurs on the connection line between the power supply and the load, at which point each control shall be checked for voltage according to the circuit map, and if the component is not functional after being directly connected to the accumulator, the component shall be shown to be poorly located or damaged。
3. If the clutch or electrical motor is not activated or stopped as required (in case of normal system pipelines), such failure occurs mainly on the control element. Switches, relays and other electronic devices are only checked for normality with special detection devices。
(1) the check of the switch is equivalent to the check of the electrical breakage through the switch。
(2) the inspection of relays is carried out primarily against their contact points and internal loop circuits, which are identical to the inspection of switches。
(3) internal coil checks can be conducted by measuring the coil resistance, which is normal if the coil resistance is about 100 times at 12v。
(4) in the event of a failure of electronic thermostats and pressure switches, it would be preferable to use a special detection device for an inspection or a replacement method for an inspection, i. E. To replace a possible malfunction with a new device of the same type。
How can air conditioning systems be neutralized
1. Electromagnetic ionomer coil damage or wire damage shall be repaired or replaced。
2. The moving v belt shall be loose or excessively worn and shall be tightened or replaced。
3. The electromagnetic centrifuge itself has noise and should be replaced。
4. The compressor shall be re-fixed or replaced by noise as a result of unsettled or fractured legs。
5. Overwatering in the system and noise from expansion valves should release refrigerants, replace liquid reservoirs, and re-refrigerate vacuums with refrigerants after filling in frozen oil。
6. Excess refrigerants cause exhaust tremors and noise, and compressor vibrations, and appropriate refrigerants should be removed from low pressure sides。
7. Evaporating wind engine noise, caused by excessive wear and tear of the electric motor or by the loss of fans, shall replace the electric motor。
The air-conditioning system works as simple as this, usually with a few failure points, and the following is an example of the usual air-conditioning failure using the iveko diesel vehicle。
How do we fix the ac panel failure
After the air conditioner has been activated, if the wind switch power signal is not on, the first check is whether the panel six core plug-in red wire is wired. If there is no electricity, check whether the central control box line is off or off. If electricity is available, it should be seen whether the steamer is working. If not, the wind switch should be overhauled or replaced. In the event of work, the light should be repaired or replaced。
The wind switch after the air conditioner is activated, the temperature switch (refrigeration) cool sign is rotated to maximum position, and the cool light is still not on, depending on whether the malfunctioning trouble light is on. If lighted, the system should be checked for failure and panel lines. If the trouble signal is not on, then check if the condenser is working. If part of the work is performed, the inside of the box should be inspected. If all the condensers are not working, the plugging and the interior of the panel should be checked。
How to rule out air conditioning temperature sensors
When the ac is activated and the ac switch reaches the maximum cooling state, only the wind signal power is activated, while the temperature indicator cool and the fail pointer trouble are not. At this point, a check should first be made of the resistance between the two white guidance lines of the three core plug-in in the control panel. If resistance exists, the control panel should be repaired or replaced. If there is no resistance, the temperature sensors should be repaired or replaced to check that the plug-in has been removed。
