5.11. The K/V compressor, - the general information and the principle of functioning

Design of the K/V compressor

Scheme of management of piston stroke size

Increase in a piston stroke

Reduction of a piston stroke

The design of the compressor of variatorny type (V-6) used in air conditioning systems of the Infiniti QX4 models is presented on the illustration К/В Compressor Design.

Basic element of a design of variatorny compressors is the shaking otboyny plate providing a possibility of management of a piston stroke depending on requirements imposed to the current refrigerating capacity of system. The size of a piston stroke of the compressor is defined by a tilt angle качающеся plates and provides the necessary level of a discharge of coolant in the range from 14.5 to 184 cm of 3 (see the illustration Scheme of Management of Piston Stroke Size).

The operating valve is switched on in the soaking-up (low pressure) part of the refrigerator highway and opens / is closed depending on pressure in a low pressure contour. Due to operations of the valve control of pressure in a case is exercised. The corner of provision of the shaking plate is defined by a difference of pressure in a case and the working cylinder.

With increase in temperature loadings pressure in a low pressure part of system also increases, in the investigation of what the bellows-sealed operating valve provides opening low pressure and closing of a high-pressure path of valves (see the illustration Increase in a Piston Stroke). Alignment of crankcase pressure with pressure in a low pressure part of system is result of such switchings. Now pressure in the working cylinder becomes significantly higher crankcase that leads to transfer of the shaking otboyny plate to the situation corresponding to the maximum piston stroke.

At the movement with high speeds, and also at low temperatures in salon or outside of the car pressure in a low pressure part of system goes down (see the illustration Reduction of a Piston Stroke). Expansion of the bellow valve happens when lowering pressure to value about 177 kPa. Thus, pressure drop in a low pressure part of system leads to closing of the soaking-up (inlet) port and opening digit (final) therefore crankcase pressure increases. The difference of pressure ahead of and behind the piston provides the effort influencing the driving finger located near the shaking otboyny plate. A driving finger with a pad take a position in which the piston develops the maximum pressure. The size of piston pressure is between Ps values (pressure in the soaking-up contour) and to relatives of Pd to it (pressure from the digit party). At increase in the crankcase pressure (Pd) at the command of management the effort influencing a driving finger leads to reduction of a tilt angle of the shaking plate and, respectively, reduction of a piston stroke.

In other words, increase in crankcase pressure leads to switching of a difference of pressure in a case and the working cylinder, and to corresponding change of an inclination of the shaking plate.

The clutch coupling of the compressor is in an active state, its compulsory disconnection from the main switch, the switch of the fan of a heater or the switch of ignition will not be made yet. Automatic shutdown of the coupling is made for protection of the compressor also at low ambient temperatures and excessive lowering of level of coolant in system.