RU2818438C1 - Two-stroke internal combustion engine with an additional piston - Google Patents

Abstract

FIELD: internal combustion engines.

SUBSTANCE: two-stroke internal combustion engine with an additional piston comprises at least one cylinder (1), a cylinder head (27), a main piston (2), a crankshaft (14), an additional piston (3). The cylinder (1) is made with an exhaust port (6) located in its lower part. Inlet check or bypass valves (9) are integrated in the cylinder head (27). The main piston (2) is made with piston rings (8) and a skirt and is connected to the crankshaft (14) of the engine. The additional piston (3) is made with piston rings and with check or bypass valves (10) built into its body. The additional piston (3) is installed in the cylinder (1) above the main piston (1). In the upper central part of the additional piston (3), a rod (4) is fixed, passing through the wall of the head (27) of the cylinder with a seal. The combustion chamber is formed between the main and additional pistons (2) and (3). The rod (4) of the additional piston (3) is made hollow and forms a plunger pair together with a hollow plunger (5) inserted into the rod (4) through its upper outer part. The plunger (5) is permanently mounted on the cylinder head (27). The stem (4) moves relative to the plunger (5) in the axial direction. At the end of the rod (4) there is a restrictive washer (12), against which the compression spring (12) abuts. The second end of the spring (12) abuts against the head (27) of the cylinder. The internal cavity of the plunger (5) is connected by a pipeline to the outlet of the hydraulic cylinder (16). The hydraulic cylinder (16) is permanently attached to the engine. The piston (17) of the hydraulic cylinder (16) interacts with the cam (15), which is mounted on the crankshaft (14) of the engine or on another shaft that rotates synchronously with it. The cavities of the rod (4), plunger (5), pipeline and hydraulic cylinder (16) are filled with working fluid.

EFFECT: simplifying the design and improving the reliability of an internal combustion engine with an additional piston.

3 cl, 6 dwg

Description

The invention relates to two-stroke internal combustion engines (ICE), namely, to two-stroke engines with an additional piston separating the intake and exhaust processes. The invention can be used both in carburetor engines and in engines with fuel injection, including diesel ones.

Internal combustion engines are known in which the operating cycle is completed in two strokes, i.e. for one revolution of the crankshaft: the first stroke is “compression” and the second stroke is “power stroke”, at the end of which the cylinder is purged with compressed air from a supercharger or with an air-fuel mixture in gasoline engines with crank-chamber purge. (Kuznetsov A.V. “Design and operation of internal combustion engines”, M.: Higher School, 1984, pp. 10-13).

A two-stroke cyclic engine is known (US patent F02B 33/04 No. 4206727 1980), containing a cylinder head with a system of rotating valves for the intake of a combustible mixture or air, a cylinder with a lower outlet window, a main piston connected to the engine crankshaft, above which it is installed an additional piston with a hollow rod that separates the mixture and exhaust gases during cleaning and new filling of the cylinder, inside the rod of which another additional valve is installed, which has a special drive connected to the engine crankshaft. The actuator provides and limits the movement of an additional piston between the cylinder head and the lower outlet port in the cylinder wall. To bypass the mixture (fresh charge) into the combustion chamber, which is formed in the space between the pistons, there is a bypass element in the form of a bypass valve in the body of the additional piston. When the main piston approaches TDC, an electrical discharge is applied to the spark plug, the fuel-air mixture between the pistons ignites and the main piston stroke occurs, during which the additional piston is at the top. After opening the exhaust window with the main piston, the pressure in the cylinder drops and at this time the additional piston, under the action of a mechanical drive, goes down, pushes out the residual gases and sucks the mixture through the intake valve.

When the main piston begins to move upward and closes the outlet port, the additional piston also moves upward under the action of the drive and compresses and bypasses the mixture through the bypass valve into the space between the pistons, after which it stops in the upper position. The main piston compresses the mixture, which is ignited with a spark plug, and the cycle repeats.

The disadvantages of this engine are: the presence of a complex mechanism for driving an additional piston containing a camshaft, gear transmissions and reciprocating mechanisms; the presence of another, additional valve built into the hollow bypass valve stem; lack of a mechanism providing an algorithm for the movement of the additional piston; the complex design of the rotating valve drive, which makes the practical application of the invention difficult.

A two-stroke internal combustion engine with an additional piston (Soldatov Engine) RU 2330970C2 2004 is known with the supply of fresh air-fuel mixture or air through the lower inlet window in the cylinder, and the exhaust gases are released through a valve installed in the cylinder head, which is opened by a rod with a head installed mainly the piston. The additional piston is driven upward by air pressure supplied by the supercharger, and driven downward by a rod with a head installed in the main piston. From the description of the patent, the diagram of the kinematic interaction of the components of the gas distribution mechanism and the mechanism of operation of the hydraulic shock absorbers, which ensure the delay of the additional piston in the extreme positions, especially at high speeds, are not clear, which casts doubt on the performance of such an engine. Also, for its operation, a supercharger is required that creates sufficient pressure to drive the additional piston upward, while the speed characteristics of the movement of the additional piston are not determined; the additional piston itself and the exhaust valve drive system have a complex design.

The closest to the proposed invention is a two-stroke internal combustion engine with an additional piston (Japanese patent, class 51 A1, (F02b), No. 47-50522, declared 02.23.70, published 12.19.72), which is taken as a prototype.

This engine has an additional piston (DP) above the main piston (OP), which moves according to a certain law as a result of the interaction of the DP rod with the cam driven from the crankshaft. The pistons move in a cylinder, in the lower part of the wall of which there is an exhaust port, and in the cylinder head there is an inlet valve. At the end of the working stroke, the OP opens the outlet window and while the OP goes to BDC and back, the outlet window is open; Under the action of the cam, the DP goes down, cleans the cylinder and at the same time sucks in a fresh portion of the mixture through the upper inlet valve. Then, under the action of the cam, the DP sharply moves upward, while the air-fuel mixture (fresh charge) is passed through a check valve built into the body of the DP into the space between the pistons. The OP closes the outlet window and compresses the mixture; The DP at this time is in the upper extreme position. A combustion chamber is formed between the pistons, where the mixture is ignited, and then a working stroke occurs, during which the DP is in the upper position.

A disadvantage of the known engine, in particular, is the presence of a kinematically complex control mechanism for an additional piston and an intake valve driven by a camshaft and cam mechanisms containing sprockets, chains, pushers and other interacting drive parts that require a complex lubrication system, and which, in the presence of high inertial loads, they become unreliable.

The objective of the proposed invention is to create a simple in design, reliable, maintainable, technologically advanced and environmentally friendly, two-stroke internal combustion engine with an additional piston.

This goal is achieved due to the fact that in a two-stroke internal combustion engine with an additional piston, including at least one cylinder with an exhaust port located in its lower part, a cylinder head in which intake check valves are built in, a main piston with piston rings and a skirt, which is connected to the engine crankshaft and moves reciprocatingly in the cylinder; an additional piston with piston rings, with check valves built into its body, installed in the cylinder above the main piston, and in its upper central part there is a rod passing through the wall of the cylinder head with a corresponding seal; combustion chamber formed between the main and additional pistons, characterized in that to control the reciprocating movement of the additional piston, a hydraulic drive system is used, containing a hollow rod attached to the upper central part of the additional piston, which is structurally a plunger pair together with a hollow plunger inserted into the stem through its upper part. At the end of the rod there is a thrust washer, against which a compression spring rests, preferably a conical one, the second end of which rests against the cylinder head. The outer end of the plunger is mounted on the cylinder head without the possibility of axial (axial) movement, and its internal cavity is connected via a pipeline (tube or high-pressure hose) to the outlet of a hydraulic cylinder permanently mounted on the engine. The cavities of the rod, plunger, pipeline, and hydraulic cylinder are filled with working fluid. The hydraulic cylinder piston interacts with a cam of a given configuration mounted on the engine crankshaft or on another shaft rotating synchronously with it. The contour of the cam determines the algorithm for the movement of the additional piston, and, with a given full entry of the hydraulic cylinder piston under the influence of the crankshaft cam, a volume of working fluid is squeezed out of the cylinder into the plunger pair strictly equal to the volume necessary to ensure the movement of the additional piston from TDC to the upper edge of the exhaust window.

The design of the engine is illustrated by the drawings presented in the figures below.

Fig.1. Where:

1. Engine cylinder

2. Main piston (MP)

3. Additional piston (AP)

4. Additional piston rod

5. Hollow plunger

6. Outlet window

7. Window for spark plug or nozzle

8. Piston rings

9. Cylinder head bypass valves

10. Additional piston bypass valves

11. Rod thrust washer.

12. Additional piston spring

13. Place of attachment of the hollow plunger

14. Crankshaft

15. Crankshaft cam

16. Plunger type hydraulic cylinder

17. Hydraulic cylinder piston

18. Hydraulic cylinder piston roller

19. Control channel fitting

20. Plunger fitting

21. Hydraulic cylinder spring

22. Hydraulic cylinder outlet channel window

23. Hydraulic cylinder outlet port

24. Edge of the outlet channel window

25. DP bypass valve spring

26. Cylinder head bypass valve spring

27. Cylinder head

TDC - top dead center

BDC - bottom dead center

HPT - high pressure tube

RVD - high pressure hose

Figure 2 shows the moment when the OP reaches the upper edge of the outlet window 6 at the end of the working stroke.

In FIG. Figure 3 shows the moment of squeezing out combustion products by an additional piston through the exhaust window and simultaneously sucking a fresh charge of the air-fuel mixture or air into the cavity between the combustion chamber and the cylinder head.

In FIG. Figure 4 shows the moment of complete cleaning of combustion products from the cavity between the OP and the DP and the end of the intake (suction) stroke of a fresh portion of the air-fuel mixture or air.

In FIG. Figure 5 shows the moment of transition of the air-fuel mixture or air from the cavity between the cylinder head and the blower into the cavity between the blower and the blower.

In FIG. Figure 6 shows the moment of pressing the air-fuel mixture OP-m when the DP is at TDC.

The engine operates as follows: See Fig. 1, which shows the moment of compression of the combustible mixture when the main piston and the additional piston are at TDC and the combustion chamber is formed between them.

When the combustible mixture is ignited, the OP moves downwards, the DP is pressed against the cylinder head. The cylinder head bypass valves 9 and the DP bypass valves 10 are closed. A working process is taking place. When the upper edge of the OP 2 reaches and passes the upper edge of the exhaust window 6 (Fig. 2), the exhaust gases rush into the exhaust manifold, the pressure in the cavity between the DP and the OP decreases, at this time or even a little earlier (advanced) the crankshaft cam 15 begins to push the piston 17 of the hydraulic cylinder 16, acting on it through the roller 18. The liquid squeezed out by the piston of the hydraulic cylinder 17 through the pipeline (tube or high-pressure hose (HPT or HPR)) comes from the control channel 19 to the hollow plunger 5, the upper end of which is fixed in place 13 on the cylinder head 27 without the possibility of axial movement, and extends the rod of the additional piston 4 relative to itself along with the DP 3, as shown in FIG. 3. At this time, an increased pressure remains in front of the DP 3, and a vacuum is formed in the cavity between the DP 3 and the cylinder head 27, as a result of which the bypass valves 10 on the DP 3 remain closed, and the bypass valves 9 on the cylinder head open. During the instant in which the main piston moves from the upper edge of the outlet window 6 to its lower edge (towards BDC) and back to the upper edge of the outlet window 6, the DP 3 reaches the upper edge of the outlet window 6, as shown in FIG. 4, thereby completely pushing out the exhaust gases from the cavity between the pistons. The time for cleaning exhaust gases and sucking in fresh fuel mixture or air corresponds to the time the crankshaft rotates through an angle from 70 to 90 degrees, which is determined by the height of the exhaust window and the applied advance of the start of the DP stroke after the working stroke. At this time, the crankshaft cam 15 releases the roller 18 of the piston of the hydraulic cylinder 17, the spring of the additional piston 12, which has a given rigidity, and which is in a compressed state at this moment, quickly moves the rod up along with the DP 3, which, in turn, squeezes out the liquid from a plunger connected by a pipeline to a hydraulic cylinder. The amount of liquid squeezed out and the corresponding stroke of the DP 3 is controlled by the contour of the cam 15 of the crankshaft 14, along which the roller of the piston of the hydraulic cylinder 18 rolls, which is installed on the outer base of the hydraulic cylinder piston and is pressed against the cam 15 of the crankshaft by the pressure force of the working fluid created by the action of the spring 12 of the additional piston 3 and the spring of the hydraulic cylinder 21. In this case, the pressure in the cavity between the DP and the cylinder head 27 increases, as a result of which the bypass valves 10 of the DP 3 open, and the bypass valves 9 of the cylinder head 27 are closed under the action of the springs 26, as shown in Fig. 5. The fuel mixture or air from the cavity between the cylinder head and the DP gradually enters the cavity between DP 3 and OP 2, and when DP 3 reaches TDC, as shown in Fig. 6, completely passes into the cavity between DP 3 and OP 2, and the bypass valves 10 of DP 3 are closed under the action of the springs of the bypass valves 25. The contour of the crankshaft cam prevents DP 3 from hitting the cylinder head 27 at the end of its stroke, because the incompressible working fluid from plunger 5 is squeezed out strictly according to the program specified by the contour of cam 15 of crankshaft 14. Moving to TDC, OP 2 pressurizes the fuel mixture, after which it ignites in the combustion chamber formed between OP and DP from a spark or fuel injection through window 7. Then all processes are repeated.

In the wall of the hydraulic cylinder, at the location of the bottom of the hydraulic cylinder piston at its final exit from the hydraulic cylinder under the influence of the working fluid squeezed out of the plunger, there is the edge 24 of the window of the outlet channel 22, connected to the expansion tank (not shown) through the fitting of the outlet channel 23. Between the inner base piston 17 of the hydraulic cylinder and the bottom of the hydraulic cylinder 16 has a spring 21 installed, pushing the piston 17 out of the hydraulic cylinder 16. By the inner base of the hydraulic cylinder piston we need to understand the base of the hydraulic cylinder piston located inside the hydraulic cylinder, and on the outer base there is a roller that rolls along the surface of the cam 15 of the crankshaft 14. Volume hydraulic cylinder, enclosed between the edge 24 of the window of the outlet channel 22 and the place of the hydraulic cylinder, where the surface of the inner base of the hydraulic cylinder piston reaches when the piston is fully extruded by the cam 15 of the crankshaft 14, is exactly equal to the volume of the rod cavity from its bottom to the inner end of the plunger 5 when the rod is fully extended, which corresponds to position of the DP when it reaches the edge of the outlet window 6. After reaching the DP TDC, the contour of the crankshaft cam allows the hydraulic cylinder piston to extend another 2-3 mm under the action of the internal spring of the hydraulic cylinder 21 with the outlet channel window 22 already open. The increased volume of the hydraulic cylinder is occupied by the working fluid coming from the expansion tank. During the reverse stroke of the piston 17, until the bottom of the hydraulic cylinder piston again reaches the edge 24 of the window of the outlet channel 22, the excess working fluid will flow through it into the expansion tank before it begins to be squeezed out by the piston of the hydraulic cylinder 17 into the plunger through the pipeline. Thus, with each stroke of the hydraulic cylinder piston, possible leaks of working fluid in the plunger pair and hydraulic cylinder will be replenished when they are worn out as a result of long-term operation, and the squeezed-out volume of working fluid will always be constant.

Cooling of the additional piston occurs due to the flow of cold fuel-air mixture or air flowing around it, passing through the channels of the bypass valves, and the main piston - due to oil sprayed onto the piston through special nozzles connected to the engine oil pump or a separate oil pump.

A single crankshaft cam can control multiple cylinders (multiple cylinders) in a multi-cylinder engine, where hydraulic cylinders can be placed around the crankshaft cam at desired angles.

A crosshead system for driving hydraulic cylinder pistons can also be used to eliminate angular forces on the walls of the hydraulic cylinder. Hydraulic cylinders can be either piston type or plunger type.

Such an engine can be supercharged, which will increase its power and efficiency.

This engine can use the same lubrication system as is traditionally used in four-stroke engines, which will increase its service life.

If we compare the open time of the exhaust valve of the four-stroke YaMZ 238 engine, which is considered the most successful diesel engine of domestic production, based on its valve timing diagram, during which the fuel combustion products cease to act on the engine piston, then it corresponds to 266-272.5 degrees from 720 degrees, corresponding to two revolutions of the crankshaft, i.e. 37% of the time it takes to complete two crankshaft revolutions. Considering that the piston stroke of the specified engine is 140 mm, in the case of transferring such an engine to two-stroke mode, with a height of the exhaust window of 10 mm, the time it takes for the edge of the OP to travel this distance back and forth corresponds to a rotation of the crankshaft by 76 degrees out of 360 degrees, which is 21% of the time it takes to complete one revolution, i.e. almost 2 times less than that of the same 4-stroke, which prolongs the time of exposure to high-pressure gases after the explosion of the fuel mixture at the OP; accordingly, the specific power related to the amount of fuel burned and, consequently, the power and efficiency of the engine increases.

This 4-stroke engine has a simultaneously open angle of the intake and exhaust valves of 40 degrees, which makes it possible for combustion products to mix with a fresh charge of the fuel mixture or air and deteriorates the quality of the combustible mixture, the completeness of its combustion, respectively, reduces power and efficiency, and reduces environmental engine class.

In the proposed engine, the possibility of mixing fresh mixture with combustion products of the previous stroke is almost completely eliminated, which increases engine power due to the completeness of combustion of the combustible mixture.

The absence of controlled intake valves, a camshaft, gears, chains, pushers, and rocker arms in the proposed two-stroke engine in comparison with the prototype simplifies the engine design, increases service life, reliability and improves its maintainability.

Keeping the lubrication system the same as for four-stroke engines increases its service life in relation to existing two-stroke engines.

Such engines can be used for installation on any type of transport and power plants. The use of such two-stroke engines is especially advisable on large-sized maritime transport, on high-speed military ships, where multi-ton, large-sized, low-speed four-stroke diesel engines are used, as well as on aircraft propeller-driven transport.

Claims (3)

1. A two-stroke internal combustion engine with an additional piston, including at least one cylinder with an exhaust port located in its lower part, a cylinder head in which intake check or waste valves are built in, a main piston with piston rings and a skirt, which is connected to the crankshaft engine shaft, an additional piston with piston rings, with check or bypass valves built into its body, installed in the cylinder above the main piston, and in the upper central part of the additional piston there is a rod passing through the wall of the cylinder head with a corresponding seal, a combustion chamber formed between main and additional pistons, characterized in that the rod of the additional piston is made hollow and forms a plunger pair together with a hollow plunger inserted into the rod through its upper outer part and permanently installed on the cylinder head, and the rod is able to move relative to the plunger in the axial direction, and a limit washer is installed at its end, against which a compression spring rests, the second end of which rests against the cylinder head, the internal cavity of the plunger is connected by a pipeline to the outlet of the hydraulic cylinder, permanently mounted on the engine, and the piston of the hydraulic cylinder interacts with a cam of a given configuration, which is mounted on On the engine crankshaft or on another shaft rotating synchronously with it, the cavities of the rod, plunger, pipeline and hydraulic cylinder are filled with working fluid. 2. A two-stroke internal combustion engine with an additional piston according to claim 1, in which a roller mounted on the outer base of the hydraulic cylinder piston is used to interact the hydraulic cylinder piston with the crankshaft cam. 3. A two-stroke internal combustion engine with an additional piston according to claim 1, in which a crosshead drive system is used to interact the hydraulic cylinder piston with the crankshaft cam.