SU89975A1 - A device for regulating the pressure in the buffer cavities of a free piston engine-compressor - Google Patents

Description

A device for regulating the pressure in the buffer cavities of a free piston compressor motor using a cam turning by means of a spring-loaded piston under pressurized air in a pressure receiver is known.

In the described device, a cylinder is used to maintain a constant position of the internal dead center of the operating pistons of the engine-compressor. associated with the rail fuel pump.

FIG. 1 shows a diagram of the device; in fig. 2, 3 and 4 - working diagrams of buffer cavities. The cavity / cylinder is connected by pipeline to the buffer cavities 2 of the engine-compressor. Chere. The calibrated orifice 3 is supplied with air from the buffer cavities into the space under the spool 4, where, due to the small flow area of the orifice 3, a pressure is established corresponding to the average pressure in the buffer cavities for the cycle. On the opposite side, the spool 4 is loaded with a spring 5 with a movable stop 6, depending on the pressure of the air supplied by the engine-compressor and the position of the rail of the fuel pump.

In the event of an increase in the average pressure in the buffer cavities that are higher than the one set, the spool 4 moves upwards, compresses the spring and communicates the buffer cavities through the valve 7 with the receiver 8, and a constant pressure is maintained. . This pressure is higher than the highest minimum pressure per cycle in the buffer cavities at various operating modes, max. and below the lowest maximum

No. 89975

The pressures in them are Rbminna. (Fig. 2). On that part of the cycle, when the pressure in the buffer cavities is higher than the Pree pressure, in receiver 8 (shaded area in Fig. 3), air will flow from the buffer cavities to the receiver. Over several cycles, the average pressure in the buffers will decrease, the spool will return to the middle position and the flow of air from the buffer cavities to the receiver will stop.

In the event of a drop in pressure in the buffer cavities below the set, the spool 4 is displaced downward and through valve 9 air flows from the receiver 8 of constant pressure to the buffer cavities on a part of the cycle (shaded in Fig. 4). The movable stop 6 provides the necessary tightening of the spring 5 and, consequently, a predetermined value of the average pressure in the buffer cavities. The position of the stop 6 is determined by the profile cam 10, which can have the following two movements that do not depend on one another: rotation around the stationary roller // as a function of the position of pressure 12, determined by pressure PI; the air supplied by the engine-compressor, and also the axial displacement along the same roller as a function of the thrust position 13 associated with the rail of the fuel pump of the engine-compressor.

The profile of the cam 10 is constructed as follows. Mentally set the fuel pump rail to the maximum feed position. Suppose that the roller 14 is in the plane of the cam 10. By setting successively different pressures / d., We find the corresponding rotation angles of the cam 10. At the same time, for each value of P, - at a given position of the fuel pump rail, we determine the fuel supply per cycle; from the work balance, the average pressure per cycle in the buffer cavity can be found at which the position of the BAIT is unchanged.

Each value of the average pressure in the buffer cavity corresponds to a certain position of the movable stop 6 and, therefore, roller 14. This makes it possible to build the profile of the cam 10 in the plane aa.

Asking successively different values of the pressure of the engine air compressor Rk {, Rkch, Rkz, Rk. and so on, for each given pressure, we find the average pressure in the buffer cavity, necessary to ensure the position of the TDC, and build profiles in the bb planes, and so on.

Thus, a cam profile can be constructed that ensures the position of the TDC at all established operating modes of the engine-compressor. In the unsteady operation mode, there will be some delay in the pressure change in the buffer cavities and, consequently, an TDC shift to one side or the other. However, this bias can be minimized in the event that there is a feedback restricting the movement of the fuel pump of the engine-compressor as a function of pressure in the buffer cavities.

Subject invention

A device for controlling pressures in the buffer cavities of a free-engine engine-compressor using a cam rotated by means of a spring-loaded piston, which is under air pressure in the pressure receiver, in order to maintain a constant position of the internal dead

points of the engine operating pistons — a compressor — used to connect the buffer cavities to the compressed air balloon through a calibrated orifice, valves, and a spring-loaded spool with a movable spring stop; the rotary cam, which controls the spool, is mechanically connected to the fuel pump rail.

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