The controller of a car air conditioner should be able to control evaporation temperature, superheat, compressor speed, opening of an electronic expansion valve, evaporator fan speed, and vehicle interior temperature according to a certain performance index. Unlike household air conditioners, the speed of the car air-conditioning compressor changes as the engine speed of the car changes.

The refrigerating capacity of the passenger car air conditioning is greatly affected by the engine speed, so the car air-conditioning control system is a multi-variable control system, and the relationship between the control parameters affects the quality of the car air-conditioning control system. Therefore, it is very important to design a controller with a simple pre-compensator for solving the sedan system of the car air conditioner.

The air conditioning system is mainly composed of compressor accumulators, expansion valves and other equipment. In a conventional semi-mechanical control system, a fixed-capacity compressor controls the on/off of the compressor through an electromagnetic clutch according to the evaporation temperature, and the thermal expansion valve reduces the pressure of the high-pressure liquid refrigerant to the evaporation pressure so that it can vaporize in the evaporator. Heat, in addition it can also control the flow to the evaporator.

Conventional fixed-capacity compressors and expansion valves have not been able to meet the requirements of high-efficiency and energy-saving automatic control. Therefore, the control system of the car air-conditioning must be studied with a new implementing agency. A multi-variable control strategy is adopted, and a variable-speed compressor and an electronic expansion valve are used to comprehensively control the evaporation pressure and the degree of superheat.

In the experiment, a variable-capacity compressor was simulated using a constant-capacity compressor driven by an AC motor, and an electronic expansion valve driven by a stepper motor was used for experiments.

Pallet Racking

Pallet racking are shelves used to store pallet goods, with strong load-bearing capacity and belong to a type of heavy-duty shelves. Pallet racking can also be called crossbeam shelves, mainly composed of column pieces and crossbeams. Although the structure is simple, the advantages of the structure are very significant. Pallet type shelves are safe, firm, and reliable, with a simple and beautiful structure. They can be adjusted and installed according to the site conditions, and the entry and exit of goods are not affected by the order of entry and exit. They are convenient and efficient, and are widely used in the storage mode of palletized goods and mechanical access by forklifts; The column pieces of the pallet shelf are connected with the columns, cross braces and slant support by bolts. The column and welded crossbeam adopt a plug-in combination structure to form the shelf frame, and the crossbeam is fixed with safety pins between the columns. This structural method is not only convenient for transportation and handling, but also allows for free adjustment of the height of each layer of the shelf space according to the height of the goods at 75mm or 50mm steps, meeting the storage requirements of different goods at different heights; The pallet type shelf can determine the layer load requirements according to the size of the column and beam specifications. The beam adopts a C-shaped buckle beam structure, which has the characteristics of large inertia moment, strong layer load capacity, strong impact resistance, light weight, and low cost; The plasticity of tray type shelves is very high. Based on tray type shelves, drawer type mold shelves, attic shelves, narrow aisle shelves, double depth shelves, pressed in shelves, automated three-dimensional warehouse shelves, etc.

Pallet Racking,Garage Shelving Systems,Warehouse Shelving,Storage Shelf

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