RU2534761C2 - Piston with fluid-drop groove - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to ICEs. In compliance with this invention, piston has fluid-drop groove cut on piston bottom side surface some 2-3 mm from fire bottom at the angle of 22 degrees relative to piston axis, 12-13 mm in length and with spherical base of radius r = 1.5 mm.

EFFECT: better compression, higher compression ratio, better combustion, lower toxicity of exhaust gases, higher engine output.

4 dwg

Description

The invention relates to power engineering, namely to engine building, and can be used in the construction of piston internal combustion engines (ICE). Structural solutions and developments are known that solve the problem of increasing compression and reducing the breakthrough of exhaust gases (exhaust) into the crankcase. Most often, this problem is solved through constructive varieties of compression rings, various grooves in the piston for collecting oil and removing carbon deposits from the cylinder walls.

However, whatever the design of the ring shape is, the exhaust gas breakthrough in the bulk occurs through the locks on the rings and the gap between the piston groove and the rings. Because of this, there is a decrease in pressure in the combustion chamber, an increase in the content of harmful substances in the exhaust gas, and a decrease in the power of the internal combustion engine.

In addition, the solution of the problem under consideration through the improvement of manufacturing technology (the tightness of the rings, the roughness of the inner surface of the cylinder liner and the outer surface of the piston) does not particularly affect the reduction of gas breakthrough. Attempts to influence the increase of compression through the piston design (barrel-shaped, taper, lowering the diameter in the piston head) do not lead to the desired results.

The closest prototype piston with an L-shaped cross-section of a ring for a diesel engine (3) can provide increased compression and reduced breakthrough of exhaust gases into the crankcase. This is accomplished by increasing the force of pressing the ring to the cylinder walls by the exhaust gases entering the surface of the L-shaped section of the ring.

However, this solution to the problem has a number of significant drawbacks:

1) increased uneven wear of the ring and cylinder liner around the perimeters due to the varying degree of bursting of the ring (gas leak through the lock);

2) increased removal of soot from the cylinder walls and, as a consequence, premature coking of the compression ring.

The aim of the invention is to improve the compression properties of the piston-cylinder liner connection, increase the compression ratio, improve the combustion of the fuel-air mixture, reduce the toxicity of the exhaust gas, increase the power of the internal combustion engine.

To achieve the intended goal, the task was to counteract the breakthrough of gas into the crankcase with the help of an air shutter between the fire bottom and the upper compression ring.

The task was achieved due to the fact that the piston with a groove according to the invention has a drop-shaped groove on the profile of the side surface of the piston bottom, cut at a distance of 2-3 mm from the firing bottom at an angle of 22 ° relative to the axis of the piston with a total length of 12-13 mm and having a spherical base with a radius of r = 1.5 mm.

The invention is illustrated by drawings, where in Fig.1 shows the design of the piston; figure 2 - the movement of gas along the annular throttle within the chopped grooves; figure 3 - layout of the piston; figure 4 - mouthpiece for visualizing the pattern of the flow of smoke.

The design works as follows.

After fuel combustion, the exhaust gas at a pressure of 7.4-7.76 MPa flows at the initial moment between the piston crown and the cylinder head, and then goes to the annular throttle formed by the walls of the cylinder and piston.

Gas flowing through an annular throttle within a cut groove has a complex flow shape. At the beginning of the current and the end of the source, the gas flow has a turbulent character, and in the gap is laminar, FIG. 2. The physical picture of the gas flow was visualized by the smoke tunnel method, which consists in introducing smoke into the ring throttle under study, which makes the flow visible in transmitted light. For this, a mock-up consisting of a piston 2 (Fig. 3) was made, made of AK4 aluminum alloy with all sizes and technological requirements that are presented to it in accordance with industry instruction 2452018I for operating a 4-hour diesel engine 8.5 / 11- 9.5 / 11, as well as a cylinder liner 3 made of plexiglass. Air was pumped into the hole in the lid 1, simulating a cylinder head, using a pump.

The imaging method used did not show a clear picture of the flow of smoke. For this reason, a special mouthpiece was made (figure 4). The body 4 of the mouthpiece was made of steel, and its cover 5 was made of plexiglass. Both parts were glued together with a gap of 0.1 mm, thus forming a throttle channel 3.

From the picture of the nature of the gas flow, it can be seen that after the mouthpiece flows through the throttle channel, it enters the tear-shaped groove. Further in the lower part of the groove is its turbulization with subsequent partial return of the jet.

Thus, the teardrop-shaped groove creates the so-called "air lock", which prevents the movement of air flow through the labyrinths of compression rings.

The air supplied through the tube 2, enters the throttle channel 3 and in the lower part of the teardrop groove is turbulent, forming an air lock, thereby providing air 1 in a larger volume to the atmosphere.

During the reverse stroke of the piston, the teardrop groove works according to the same principle, capturing the air mass and raising it with a higher pressure than the serial piston.

As patent research and manufacturing practice shows, our proposed solution to the problem of reducing gas breakthrough through a change in piston design is most optimal and has no analogues in world practice. According to our field tests, a drop-grooved piston compared to the serial one showed an increase in compression ratio from ε - 17 for a serial piston to ε - 17.8 for an experienced one; specific fuel consumption for a serial piston at 100% P _e 248 g / kW · h (182 g / hp · h), for a pilot 245 g / kW · h (180.5 g / hp · h) . Checking exhaust gases for smoke according to GOST 24.028-80 showed the following values for smoke:

(по ГОСТ ≤1,84);- for serial engine $${\mathrm{TO}}_m^{-\mathrm{one}}=\mathrm{1,5}$$

(according to GOST ≤1.84);

.- for developed $${\mathrm{TO}}_m^{-\mathrm{one}}=1.35$$

.

The disadvantages of the considered design solution include a small deposits of soot in the lower part of the teardrop groove, however, subject to operating rules, it will not exceed the resource until the first bulkhead.

Literature

1. A piston with an additional air-accumulating chamber for an internal combustion engine running on gasoline.

US Patent 4,592,318. Claim 09/23/83, No. 535336, publ. 306.86. MKI F02B 17/00.

2. The piston of the diesel engine.

Application 61-1900153, Japan. Claim 02/19/85, No. 60 - 29337, publ. 08/23/86. MKI F02F 3/28, F02B 23/00.

3. A piston with a combustion chamber in the bottom and an upper ring of an L-shaped section for a diesel engine.

Development of headland ring and piston for a four - stroke direct injection diesel engine Me Lean Douglas H., Bremfoerder Fred W., Hamelink Joseph C. “Diesel Engine Components: Power Cylinders and Pistons. Int. Congr. and Expo., Detroit Mich., Febr. 24-28, 1986. " Warrendale, Pa, 1986, 41-48.

4. Overview information. Design and operation of equipment. Series 4 - Internal combustion engines; Series 5 - Foreign design of the internal combustion engine piston rings. M., 1986.

Claims (1)

A piston with a groove, characterized in that it has a drop-shaped groove on the profile of the side surface of the piston bottom, cut at a distance of 2-3 mm from the firing bottom at an angle of 22 ° relative to the axis of the piston with a total length of 12-13 mm and having a spherical base of radius r = 1.5 mm.

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