DE1451962A1 - Two-stroke internal combustion engine and piston for this - Google Patents

Description

The British Internal Combustion Engine Research Institute limited

1 Sep 6 1968

Two-cylinder internal combustion engine and pistons for this (addendum to patent 1 256 941)

The invention relates to internal combustion engines and pistons therefor, and more particularly to a method and a device for changing the compression chamber in the cylinder of a two-stroke internal combustion engine to increase the efficiency of this machine.

The main patent 1 256 941 relates to a two-stroke internal combustion engine, with a two-part piston, the two piston parts ^ QgSSfiEEJqiSee ^^ axially relative to each other within a limited maximum range depending on a predetermined, to be maintained for each piston clearance, maximum combustion chamber pressure with a corresponding change in the combustion chamber volume (and thus of the compression ratio) are movable, the one piston part forms at least part of the piston top and the other piston part with the drive shaft in Connection is and between the two piston parts one

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Variable volume chamber is provided, which has a Line located in the piston part connected to the drive shaft for supplying liquid from the connection is connected to the drive shaft and via another line and one provided therein, when the Maximum combustion chamber pressure opening outlet check valve to the lower outside of this piston part in Connection.

Another feature of the invention described and claimed in the main patent is that the pressure generated by the deceleration of the oil column located in the connecting rod or connecting rod at approximately top dead center, in conjunction with the normal lubricating oil pressure, is used to charge a small amount of oil Cylinder and a spring-loaded piston "existing oil reservoir " can be used in the further course of the work cycle, when the machine piston moves over the lower part of its stroke and the pressure in the hydraulic chamber defined between the inner and outer main sections of the piston is low , the spring pushes the oil out of the reservoir into the hydraulic chamber, so that with each work cycle there is a small movement of the outer piston part relative to the inner part, thereby increasing the distance between the piston crown and the inner piston part »

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In a further development of this basic idea, this movement is according to the invention in the direction of a reduction in the compression space by the pressure of a produced by means of a mechanical pump supplied fluid.

The solution according to the invention "consists in a two-stroke internal combustion engine of the type described in the main patent in particular that to produce the axial Relative movement and enlargement of the distance between the two piston parts from one another in one of these a pump for delivering a predetermined amount of liquid in each case is provided, the inlet side of which has a suction check valve with the liquid supply line and its The outlet side is connected to the chamber via a discharge check valve, and that this pump is on approach against the bottom piston dead center actuating device is provided. '

In the drawings are two exemplary embodiments of the invention shown. Show it:

1 shows a section through an internal combustion engine piston with the features of the invention,

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Mg. 2 a partial section through the piston according to FIG. 1 with the connecting rod in a different position,

Mg. 3 shows a partial section through another embodiment of the invention,

Fig. 4 shows a longitudinal section through the pump of the embodiment of the invention according to Fig. 3, on an enlarged scale Scale,

Mg. 5 and 6 the Pig. 3 bsw. 4, similar views of modified piston and pump assemblies;

Mg. 7 a section through a flask with two parts existing piston crown.

According to Mg. 1, in which one for a hollow piston internal combustion engine A suitable arrangement shown is a portion 1, 2 of the outer surface of the thin end of a connecting rod 3 designed so that it serves as a cam surface which, when the connecting rod 3 is pivoted, a piston tappet 4 displaced. When the connecting rod has reached the end of its counterclockwise movement path during the working stroke of the piston, it takes place

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contact with the piston plunger 4 according to Mg. 1 at 1. After "After working stroke and the beginning of the compression stroke verschwenlct the connecting rod in a clockwise direction, the piston plunger 4 by the Abwälzwirkung of section 1 _f 2 according to Pig. 2 to the left against a Return spring 5 is displaced and in the process lubricating oil is pumped into a hydraulic chamber 7 via a one-way or non-return outlet valve 6.

During the rest of the work cycle of the internal combustion engine the connecting rod pivots counterclockwise, the piston tappet 4 by the Return spring 5 is shifted to the right. A one-way or check inlet valve 8 opens and lets Lubricating oil entering via a feed channel 9 in the connecting rod via a foot valve 10 into the space behind the Enter piston tappet, which is filled by the oil.

The compression ratio of the internal combustion engine is primarily in Depending on the highest pressure acting on the piston changed, so that under all working conditions the Internal combustion engine the maximum permissible compression and expansion ratios can be achieved. Diameter and stroke of the piston tappet are selected * that a movement

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from about 0.01-0.02 mm of the outer bulb part relative to the inner piston part is brought out to a reduction in size to effect the compression space. Palis this effect does not exceed the predetermined maximum value causes maximum cylinder or combustion pressure, the small movements mentioned are continued with each piston stroke until this maximum value is temporarily reached is exceeded by a small amount. As soon as this is the case, an outlet valve arrangement 11 is actuated, which drains a correspondingly small amount of oil. When the machine is working at constant power, it moves thus the outer piston part upwards and downwards a little relative to the inner part with each power stroke.

The continued movements that serve to increase the compression ratio take place when the power output the internal combustion engine is to be reduced and the maximum cylinder or combustion pressure otherwise below would fall the predetermined maximum value. There is no need for a sudden increase the compression ratio, since a few work cycles at lower than the maximum combustion pressure have no adverse consequences. However, when the machine power is increased, the maximum spreading pressure is achieved

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would suddenly increase and damage the machine is a rapid decrease in the compression ratio necessary. The exhaust valve assembly 11 is therefore designed so that under these conditions a large AusBlauffläche is released, which allows a quick ejection of oil from the chamber 7, so that the maximum combustion pressure does not exceed the predetermined value.

When a large cyclical expansion of the hydraulic chamber 7 occurs, for example when it is slowly spinning the internal combustion engine by hand or by means of a motor, both valves 6 and 8 open and enable a direct oil flow from the supply channel 9 into the hydraulic chamber 7, the latter being kept filled with oil.

3 and 4, an arrangement suitable for a crosshead machine with the features of the invention is illustrated. In this case, the piston tappet 12 of a pump arrangement 13 has a one-way and Check inlet valve 14, while a sleeve 15 at its upper end is a one-way or check outlet valve 16 has. The lubricating oil is directed to the underside of the inlet valve 14 via channels 17 and 18. .

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When the piston is at the outer or bottom dead center When approaching the position, the protruding end of the piston tappet 12 comes into contact with a stationary stop 19 and the piston tappet leads its delivery stroke relatively during the further movement into the dead center position to the sleeve. If desired, a return spring can be used be provided, although in the present case no such spring is shown, since even if the normal Lubricating oil pressure during the acceleration of the piston from the outer or bottom dead center position due to inertia the oil column in the connecting rod is exceeded, the inertia effect later the lubricating oil delivery pressure supported or reinforced, if the piston movement when approaching the inner or top dead center so that the piston tappet is in its outer position is pressed. Although a leather like the one in a smaller hollow piston machine 1, it may be desirable to prevent the pump from filling when the machine is slowly cranking in cold To ensure condition, crosshead machines are usually so large that they come with a device for ensuring a sufficient lubricating oil pressure can be equipped when starting.

According to Fig. Β, the pump can, for example, also in one

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See "the moving part of the crosshead is arranged and, according to Pig. 5, can be connected to the piston via a channel 17 provided in the connecting rod 3 , the fixed stop 19 being arranged accordingly 16 leading into the hydraulic chamber channel 17 · The ropes according to Figures 5 and 6 work in the same way as the similarly designated parts according to Figures 3 and 4 «

In the case of the arrangement according to Pig. 5 applicable embodiment of the invention according to Pig. 7 again the pump device according to Pig. 6 used. The piston crown or the piston crown in this Pail consists of two parts, ie an inner piston-like part 21 is inserted longitudinally displaceably into a cylinder recess provided in the outer, cup-like part 22. A ring 23 inserted into a groove in the wall of the outer part 22 serves to limit the longitudinal or axial movement of the inner part of the piston.

The variable volume chamber 7 is formed between the two piston parts. The flask according to Pig. 7 works similar to the arrangement according to the Pig. 5 and 6.

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The pistons can be adjusted accordingly Mg. 1 and 3, similar to the construction according to Mg. 7, be designed with a two-part piston crown.

Of course, the above description is only intended to be exemplary in all respects, since numerous details, in which the invention is embodied can be modified without departing from the scope of the invention will.

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Claims (6)

Claims 1. Two-stroke internal combustion engine, with a two-part Piston, the two piston parts (according to patent 1 256 941) axially relative to each other within a limited maximum range as a function of a predetermined maximum to be observed for each piston clearance Combustion chamber pressure with a corresponding change in the combustion chamber volume (and thus the Compression ratio) are movable, the one piston part forms at least one cable of the piston top and the other piston part with the drive shaft is in connection and a volume-variable chamber is provided between the two piston parts is, via a line located in the piston part connected to the drive shaft for the supply of Fluid is connected from the connection to the drive shaft and via a further line and a provided therein, When the maximum combustion chamber pressure is exceeded, the outlet check valve opens to the lower one Outside of this piston part is in connection, characterized in that to produce the relative axial movement and increasing the distance 909811/0625 ** D o? H «nal - 12- SUO C / nferiagen (M-7§iAi * .2Nr. ISateSifcs Amendment Ges. V. 4 9.196 of the "two piston parts from each other in one of these a pump (4 or 12) is provided for pumping a predetermined amount of liquid, the Input side via a suction check valve (8) with the liquid supply line (9) and its output side is connected via a discharge check valve (6) to the chamber (7), and that a pump when approaching the piston bottom dead center actuating device is provided. 2. Internal combustion engine according to claim 1, characterized in that the chamber is provided with a pressure relief valve which enables an ELuidum exit when the in the pressure prevailing in the chamber exceeds a predetermined maximum value. 3. Internal combustion engine according to claim 1, characterized in that that a central area of the piston head is formed by an additional or auxiliary piston, which to move relative to the "circumferential section of the piston head able. 4. Internal combustion engine according to claim 1 or 2, characterized in that that the mechanically operated pump is located inside the piston and one in a cylinder 909811/0625 ^ ₀₀ K; -13- U51962 the arranged piston piston el and that at the upper end of the Yerbindungs- or connecting rod, a curve-like member is provided, which the piston tappet shifted in its cylinder against the action of a leather when the connecting rod is at the end of the working stroke and at the beginning of the compression stroke of the piston pivoted from one side to the other. 5. Internal combustion engine according to claim 1 or 2, characterized in that that the mechanically operated pump is arranged in the piston and one guided in a cylinder Has piston tappet and that a fixed stop is provided on a part fixed to the machine which comes into contact with the piston tappet of the pump and displaces the piston tappet in its cylinder, when the piston approaches the outer or bottom dead center. 6. Internal combustion engine according to claim 1 or 2, characterized in that that the mechanically operated pump is arranged outside the piston and one in one Has cylinder guided piston tappet and that a stop is provided which the piston tappet at touches the approach of the piston to its outer or bottom dead center and displaces it in its cylinder. - 14 - 809811/0625 7 »internal combustion engine naoh claim 4» characterized that it is a crosshead machine and that the pump on the crosshead and the stop on a machine fixed part "are attached. nm 909811/0625