The Basic Knowledge Point Of Auto AC Compressor

November 17 12:38 2021

The Auto AC compressor is the heart of the ac system and the power source for the refrigerant to circulate in the system. It is driven by car’s engine via a series of belts and pulleys.Our company is specialized in the after-sale market & supporting services for automotive air conditioning compressors. Our main product series include 5H,5S,5L,7H,10PA,10S,6SEU,6SBU,7SBU,7SEU,FS10,HS18,HS15,TM,V5,CVC,CWV, Bock, etc. The car ac compressor is used widely for all models of automobiles such as Mercedes Benz, BMW, Volkswagen, Opel, Ford, TOYOTA, Honda, Renault, and so on. The vehicle types include sedans, heavy-duty trucks, engineering trucks, mini-vehicles, and agricultural & mine trucks or lorries.We have advanced production equipment, precise testing instruments, and a professional technical team, which provide quality and technical assurance for the production of the product, and we have passed the authentication of ISO/TS16949.

Automobile Air-conditioning Compressor working principle

When the car ac compressor works, it sucks in low-temperature, low-pressure liquid refrigerant, and discharges the high-temperature, high-pressure gaseous refrigerant from the discharge end.

Constant displacement compressor:

The displacement of a constant displacement compressor increases proportionally with the increase of the engine speed. It cannot automatically change the power output according to the demand for refrigeration, and it has a relatively large impact on the engine’s fuel consumption. It is generally controlled by collecting the temperature signal of the air outlet of the evaporator. When the temperature reaches the set temperature, the electromagnetic clutch of the car ac compressor is released and the ac compressor stops working. When the temperature rises, the electromagnetic clutch is engaged and the auto ac compressor starts to work. The constant displacement compressor is also controlled by the pressure of the auto air conditioning system. When the pressure in the pipeline is too high, the automotive air conditioning compressor stops working.

Variable displacement compressor

The variable displacement compressor can automatically adjust the power output according to the set temperature. The air-conditioning control system does not collect the temperature signal of the air outlet of the evaporator but controls the compression ratio of the ac compressor according to the change signal of the pressure in the air-conditioning pipeline to automatically adjust the air outlet temperature. In the whole process of refrigeration, the compressor is always working, and the adjustment of refrigeration intensity is completely controlled by the pressure regulating valve installed inside the car compressor. When the pressure at the high-pressure end of the air-conditioning pipeline is too high, the pressure regulating valve shortens the piston stroke in the car compressor to reduce the compression ratio, which will reduce the refrigeration intensity. When the pressure at the high-pressure side drops to a certain level and the pressure at the low-pressure side rises to a certain level, the pressure regulating valve increases the piston stroke to increase the intensity of refrigeration.

Automotive AC Compressor classification

According to different working methods, auto ac compressors can generally be divided into the reciprocating compressors and rotary compressors. Common reciprocating compressors include crankshaft connecting rod type and axial piston type, and common rotary compressors include rotary vane type and scroll type.

1. Crankshaft Connecting Rod Compressor

The working process of this type of compressor can be divided into four, namely compression, exhaust, expansion, and suction. When the crankshaft rotates, the connecting rod drives the piston to reciprocate, and the working volume formed by the inner wall of the cylinder, the cylinder head, and the top surface of the piston will periodically change, thereby compressing and transporting the refrigerant in the refrigeration system

The application is relatively wide, the manufacturing technology is mature, the structure is simple, and the requirements for processing materials and processing techniques are relatively low, and the cost is relatively low. Strong adaptability, can adapt to a wide pressure range and cooling capacity requirements, strong maintainability.

However, crankshaft connecting rod compressors also have some obvious shortcomings, such as the inability to achieve higher speeds, the large and heavy machines, and it is not easy to achieve lightweight. The exhaust is not continuous, the airflow is prone to fluctuations, and there is greater vibration during work.

2. Axial Piston Compressor

The main components of the axial piston compressor are the main shaft and the swashplate. The cylinders are arranged circumstantially with the main shaft of the compressor as the center, and the movement direction of the piston is parallel to the main shaft of the compressor. The pistons of most swash plate compressors are made as double-headed pistons. For example, in an axial 6-cylinder compressor, 3 cylinders are at the front of the compressor, and the other 3 cylinders are at the rear of the compressor. The double-headed pistons slide one after the other in the opposed cylinders. When one end of the piston compresses the refrigerant vapor in the front cylinder, the other end of the piston sucks the refrigerant vapor in the rear cylinder. Each cylinder is equipped with a high and low-pressure gas valve, and a high-pressure pipe is used to connect the front and rear high-pressure chambers. The swashplate is fixed with the compressor main shaft, the edge of the swashplate is fitted in the groove in the middle of the piston, and the piston groove and the edge of the swash plate are supported by steel ball bearings. When the main shaft rotates, the swash plate also rotates, and the edge of the swash plate pushes the piston to make an axial reciprocating movement. If the swash plate rotates once, the front and back two pistons each complete a cycle of compression, exhaust, expansion, and suction, which is equivalent to the work of two cylinders. If it is an axial 6-cylinder compressor, 3 cylinders and 3 double-headed pistons are evenly distributed on the section of the cylinder block. When the main shaft rotates once, it is equivalent to the effect of 6 cylinders.

The swash plate compressor is relatively easy to achieve miniaturization and lightweight and can achieve high-speed operation. It has a compact structure, high efficiency, and reliable performance. After realizing variable displacement control, it is currently widely used in automobile air conditioners.

3. Rotary Vane Compressor

There are two types of cylinder shapes for rotary vane compressors, circular and elliptical. In a circular cylinder, there is an eccentricity between the main shaft of the rotor and the center of the cylinder, so that the rotor is close to the suction and exhaust holes on the inner surface of the cylinder. In an elliptical cylinder, the main axis of the rotor coincides with the center of the ellipse. The blades on the rotor divide the cylinder into several spaces. When the main shaft drives the rotor to rotate once, the volume of these spaces continuously changes, and the refrigerant vapor also changes in volume and temperature in these spaces. The rotary vane compressor has no suction valve because the vane can complete the task of sucking and compressing refrigerants. If there are 2 blades, the main shaft rotates once and there are 2 exhaust processes. The more blades, the smaller the discharge fluctuation of the compressor.

Rotary vane compressors require high machining accuracy and high manufacturing costs.

4. Scroll Compressor

The structure of the scroll compressor is mainly divided into two types: static and dynamic type and double revolution type. At present, dynamic and static applications are the most common. Its working parts are mainly composed of a dynamic turbine and a static turbine. The structures of the dynamic and static turbines are very similar. Both are composed of endplates and involute scroll teeth extending from the endplates. The two are eccentrically arranged with a difference of 180°. The static turbine is stationary, while the moving turbine is driven by the crankshaft to rotate and translate eccentrically under the constraint of a special anti-rotation mechanism, that is, there is no rotation but only revolution. Scroll compressors have many advantages. For example, the compressor is small in size and light in weight, and the eccentric shaft that drives the moving turbine can rotate at a high speed. Because there is no suction valve and exhaust valve, the scroll compressor operates reliably, and it is easy to realize variable speed movement and variable displacement technology. Multiple compression chambers work at the same time, the gas pressure difference between adjacent compression chambers is small, the gas leakage is small, and the volumetric efficiency is high. The scroll compressor has the advantages of compact structure, high efficiency and energy-saving, low vibration and low noise, and working reliability.

Main Series of Automobile AC Compressor

Auto AC Compressor Replacement

When the original compressor was damaged, it may be caused by serious issues in the air conditioning system. The most common problems in air conditioning systems are: 

(1) Poor heat dissipation or too much gas – both will result in too high pressure produced by the compressor, which leads to the damage of the pressure plate and connecting rod parts.

(2) After a long period of use of the vehicle, the car ac compressor will be aging, it will bring the organic carbon, which will cause the pipe clogging or receiver drier failure, it can’t filter the moisture and then lead to the ice block;

(3) If the pipeline is not installed or fixed, after a prolonged swing, it will result in loose air leakage.

Be sure to perform the following steps before replacing the auto ac compressor:

(1) Separate the hoses in the system and clean them, pour the cleaner into the pipelines of condenser and evaporator, then soak for about 20 minutes. The next step is to use high-pressure nitrogen to wash out the dirt and cleaner. The following parts cannot be flushed but need to be replaced: auto ac compressor, receiver drier, and throttling tube. After flushing the system once, check if impurities are left. If so, try to flush the system again. 

(2) Please clean the surface of the condenser and evaporator, and check the speed of the radiator fan.

(3) Clean or replace the expansion valve, the receiver drier and pipe filter must be replaced.

(4) Vacuum, fill in with the gas, check low and high pressure (low pressure 30-40 Psi, high pressure is 180-200 Psi). If the pressure is different, please diagnose the system before running the air conditioning system.

(5) Check and correct the volume and viscosity of the oil. And then install the auto ac compressor.

Package and Delivery

1. Package: each ac compressor in one box, 4 pcs in one carton.Neutral packing or color box with Brand Bowente or as your requirements.

2. Shipping: By Express (DHL, FedEx, TNT, UPS), By Sea, By Air, By Train

3. Export sea port: Ningbo, China

4. Lead time: 20-30 days after deposit into our bank account.

Media Contact
Company Name: Ningbo Bowente Auto Parts Co Ltd
Email: Send Email
Phone: +86-574-55664791
Country: China
Website: https://www.chinacparts.com/