US2076258A - Crankless motor compressor - Google Patents

Description

April 6, 1937. R. WITKIEWICZ ET AL 2,076,253

CRANKLESS MOTOR COMPRESSOR Filed March 16, 1933 Patented Apr. 6, 1931 UNITED STATES PATENT OFFICE".

2,076,258 CRANKLESS Moron comrnnsson Roman Witkiewicz and Adam Wichiski, Lwow, Poland Application March 16, 1933, Serial No. 661,194 In Poland March 23, 1932 1 Claim. (Cl. 230-56) Applications have been filed in Poland, on March 23, 1932; in Germany, Austria, and Switzerland on December 12, 1932; in the Free City Danzig on December 14, 1932; in Czechoslovakia on De 5 cember 16, 1932; in Sweden on December 20, 1932;

o compressors, and more particularly to a method in Italy, Hungary, Rumania, and France on December 22, 1932; in Belgium on January 6, 1933, and in Denmark on January 5, 1933.

a The present invention relates to crankless motor The hitherto known constructional forms of crankless motor compressors possess the disadvantage that the magnitude of stroke of the compressor parts cannot be fully utilized inasmuch as only a part of the air contained in the said compressor parts can be usefully discharged. The rest of the expanding air has to perform the work necessary for the production of the compression in the motor part of the motor compressor. This results in a considerable diminution of the compression pressure dependent upon the load of the compressors. As a result of this difiiculties are caused in consequence of .the necessity for automatic alteration of the pointof injection of full independence on the load and alsoin consequence of the low stability of the automatic regulation process, which may exhibit itself by causing un'ceasing disturbances during the pas-'- sages from one state of equilibrium to anotherrone.

It is one object of the present invention to remove this disadvantage by the employment of the structure hereinafter described for the at tainment of a uniform or approximately uniform compression pressure in the motor part of a crankless motor compressor. A particularly novel feature of theinvention resides in the fact that an invariable compression pressure is obtained by the aid of the work of expansion of the gases which are not discharged from the compressor, this work being, however, utilized in combination with the work of expansion of air in a separate air buffer chamber or chambers. The latterv is intended to eifect an accumulation of energy during the compression -periodin the compressor parts to'such an extent that thgsum of the energy imparted to the piston by the air bufi'er chambers and by thev gas expanding in the compressor during. .the movement of the piston to-- wards the motor part of the-motor compressor is of constant or substantially constant magnitude independently of the, load at any given time. At the same time the losses of air arising in the buiier chambers in consequence of lack of air tightness are compensated for by arranging that air is taken up from the atmosphere or from a compressed air container by the opening of ports in the cylinder by the faces of the piston during the beginning of the movement of the latter. A compensation of the losses of air arising in the bufier chambers may also be effected by means of an automatic suction valve arranged in the said chamber, for example on the cover thereof.

A crankless motor compressor constructed for carrying out the aforesaid method according to the invention possesses the further advantage that the air sucked in by the compressor is not ,throttled, inasmuch as a diminution of the quantity. of air discharged is obtained by diminishing the quantity of fuel injected with the result that the stroke of the pisggn towards the compression space of the compres r automatically diminishes.

A preferred constructional form of a two-stroke cycle motor compressor adapted for carrying out the method according to the invention is illustrated by way of example on the accompanying drawing, in which:

Fig. 1 is a vertical longitudinal motor compressor, and

Fig. 2 is a plan thereof partly section.

Referring to the drawing:

The motor compressor is provided with a cylinder I having an internal chamber 2 in which a combustion engine cycle, for example according to the Diesel system, takes place. The cylinder L is provided with ports 3 serving for the exhaust and ports 4 serving for the scavenging of the inner chamber 2 of the cylinder, the air necessary for scavenging being derived froma container 5. At the ends of the motor compressor, cylinders Band I are provided having chambers 8 and 9 in which the compressor operations take place. The cylinders 6 and l are provided with enlarged section of the in horizontal portions in which bufier pistons 12 and I3 reciprocate, which latter form an integral unit with the outer compressor pistons and the inner motor pistons. The pistons l2 and I3 are connected with one another by means .of a linkage comprising link members l4 and I and swinging members l6, whereby the synchronism of the oppositely directed movements of the two pistons is ensured. V

Ports l1 and It provided in the cylinders 6, I serve for the suction of air into the scavenging pump, which is constituted by the annular chamber l9 located around the chamber 2 of the middle cylinder between the' pistons 82 and H3. The ports I! and I8 also serve for the compensation of the losses of air arising in the buffer chambers l0 and II in consequence of the unavoidable lack of complete air tightness.

The valves 20 and 25 serve for the admission of fresh air into the two compressors and the valves 22 and 23 form the pressure valves of the compressors. The ports 25 together with the conduits 21 and 28 serve for the completion of the charge of the compressor from the scavenging pump chamber E9.

The new process elucidated by way of example with reference to the mode of operation of the motor compressor described is based on the fol lowing principle. During the movement of the pistons i2 and i3 inwards from the outer position illustrated, the air which has remained in v the compressor chambers 8, 9 is expanded and fresh air is then sucked in. At the same time the air contained in the buffer chambers l0 and II also expands, the sum of the two amounts of work simultaneously executed being converted into the kinetic energy of the pistons l2 and I 3. The said kinetic energy is converted in the further course of the operations into the work necessary for compressing air in the motor chamber 2 and also in the chamber 19.

Shortly before reaching the inner dead centre the part 24 of the piston I uncovers the ports 4 establishing communication with the pump, whereby the container 5 is charged with the air intended for scavenging. The buffer pistons l2 and I3 uncover the ports I! and I8 whereby air is supplied to the buffer chambers to compensate for the losses through lack of air tightness therein.

Immediately before the inner dead centre position of the pistons i2 and I3 is reached fuel is injected by means of the fuel injection valve 25 into the chamber 2. After injection of the fuel the combustion takes place in the said chamber, the pistons alter their direction of movement audzthe combustion gases expand in the chamber At the moment when the ports 3 are uncovered by the inner pistonsthe combustion gases escape and the piston l3 uncovers the scavenging ports 4 after the attainment of atmospheric pressure in the cylinder I. The scavenging air then flows from the container 5 into the cylinder 2 and forces the exhaust gases out, these latter escaping through the ports 3.

During this return stroke the air in the scavenging pump chamber l9 expands, and at the moment when the ports I! and I8 are uncovered the scavenging pump draws in the quantity of air which is necessary for charging the container 5 later on. At the same time the air in the buffer chambers l0 and II is compressed, this operation commencing immediately after the ports I! and 18 have been covered by the pistons l2 and I3. At this time after the working pressure has been attained air is forced out through the compression valves 22 and 23.

At the end of the suction stroke the compressor pistons uncover the ports'26 communicating by additional charging with the container '5 for the scavenging air. In this case, however, the compressor would be charged to a somewhat lower pressure than that of the scavenging air.

During the movement of the pistons whereby the combustion gases expand in the motor, the kinetic energy of the pistons I2 and I3 is greater, the greater the quantity of injected fuel. In consequence of this the piston stroke and the amount of air delivered from the compression chamber of the compressor is likewise greater, the greater the quantity ofinjected fuel. The quantity of energy given up by the expanding gases in the compressor will therefore in this case become smaller and smaller, but at the same time the quantity of energy yielded up by the buffer chamber to the piston must increase in consequence of the increase of stroke and the consequent increase of the pressure in the buffer chamber. It is not difiicult to arrange that the size of the bufier chamber in proportion to the dimensions of the compressor is such that the sum of the quantities of energy given up by the compressor and the buffer to the piston shall be invariable or only slightly variable with the load. This principle therefore results in an approximately uniform final compression pressure of the fuel mixture or the air in the combustion chamber of the motor 2.

If the compensation of the air or gas losses resulting from lack of air tightness in the buffer is effected by means of air at a lower pressure than .8 of an atmosphere above atmospheric pressure (air at atmospheric pressure or at the pressure of the scavenging pump) then the realization of the principle of approximately uniform compression pressure in the motor is only possible in the case when the operative buffer area is greater than the cross sectional area of the motor cylinder. If, on the other hand, pressures of more than .8 of an atmosphere above atmospheric pressure are employed, then the operative buffer area may be smaller than the cross sectional area of the motor cylinder. However, in view of the danger of explosion of lubricants and also in view of the heat losses in the buffer, the ratio 01 the final compression pressure to the initial pressure must not be greater than 10 at the highest possible load.

From the above it follows that the characteristic features of a motor compressor operating according to the invention reside in the facts that (a) the pressure ratio in the buffer is lower than 10, and (b) the operative buffer area is greater than the cross sectional area of the motor cylinder, if the initial pressure in the buffer is less than .8 of an atmosphere above atmospheric pressure.

The crankless motor compressor described does not require any regulating apparatus for adapting the motor output to the compressor output. The adjustment of the quantity of fuel according to the load may be automatically effected dependently upon the pressure above atmospheric pressure in the container for the air which is delivered. 4

The fact that the admitted air is not throttled at variable load does not cause any additional losses.

means of conduits 21 and 28 with the scavenging w claim;

pump chamber l9, with the result that the compressors are additionally charged from the said scavenging pump. In this latter the pressure is somewhat higher dln'ing the additional charging than that of the scavenging air. It would also be possible to connect the ports 26 for the In a crankless motor compressor comprising a motor cylinder, two buffer cylinders mounted coaxially with said motor cylinder one at each side thereof, two compressor cylinders mounted coaxially with said motor cylinder one at each side thereof, and two multiple direct-acting free-flying the pistons is larger than the active surface of the parts acting as motor pistons, whereby a substantially constant final pressure of the compression in the motor, independently of the load,

is attained.

ROMAN WITKIEWICZ.

ADAM wIcIfisKI.

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