JPH0210268Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an internal combustion engine having a sealing air supply/discharge mechanism in the cylinder. The invention relates to an internal combustion engine. This pushes catalyst particles, combustion residue, and combustion gas existing in the top ring and the gap between the piston and cylinder liner above the top ring back into the combustion chamber, preventing them from entering the piston ring sliding surface, It is used in the field of reducing wear between piston rings and cylinder liners.

[Conventional technology]

In recent years, the quality of the fuel oil used in marine diesel engines has been deteriorating, and among these, fuel oil containing hard catalyst particles called FCC oil is increasingly being used. If such fuel oil is used, the cylinder liner and piston ring, which are constantly sliding, will wear out due to catalyst particles and fuel residue, causing serious trouble in the engine.

In order to solve this problem, the applicant proposed the
In Japanese Patent No. 42138, an annular pocket 4 is provided in the piston 1 over the entire circumference between the top ring 2 and the second ring 3 fitted on the piston 1 as shown in FIG. A piston for an internal combustion engine has been proposed in which air is supplied from the supply device 5 near the top dead center of the piston 1.

According to this, when the piston 1 approaches the top dead center, sealing air with a pressure higher than the cylinder internal pressure is supplied to the air supply hole 6 between the two rings.
During the combustion stroke, clean air flows into the cylinder through the top ring 2, removing catalyst particles, combustion residue and The combustion gas is pushed back into the combustion chamber 9, making it possible to prevent catalyst particles and the like from entering the piston ring sliding surface.

[The problem that the idea attempts to solve]

By the way, the above-mentioned high-pressure air is supplied to a valve opening/closing control device 10 and a high-pressure air compressor that are separately provided outside the cylinder to open and close the air supply hole 6 provided in the cylinder liner 7 according to the operation of the piston 1. Although the air is supplied by a high-pressure air supply device 5 having 11, the supplied air disappears inside the cylinder as it is. That is, most of the high pressure air supplied to the pocket portion 4 between the top ring 2 and the second ring 3, for example about 80%, leaks to the crank chamber side through the piston rings below the second ring 3. The remaining air leaks to the combustion chamber 9 side through the top ring 2. And top ring 2 and second ring 3
The air supplied between the piston 1 and the piston 1 gradually leaks as described above as the piston 1 moves toward the bottom dead center during the expansion stroke, so that the pressure in the pocket portion 4 decreases. However, in a four-stroke engine, for example, the piston 1 moves to the bottom dead center during the expansion stroke, returns to the top dead center during the exhaust stroke, and then returns to the bottom dead center during the air intake stroke, at which point the entire stroke is almost completed. , the supplied air disappears.

Therefore, when the air compressor of the high-pressure air supply system generates high-pressure air for the next cycle, outside air must be taken in and compressed, consuming 3 to 5% of the engine output as a power source. It turns out.
Therefore, in order to obtain high-pressure air for reducing the wear described above, there is a drawback that the engine output must be reduced, and an improvement is strongly desired.

The present invention was made to solve the above-mentioned drawbacks, and its purpose is to recover the sealing air supplied into the cylinder when generating high-pressure air with a high-pressure air supply device, and reuse it again. To provide an internal combustion engine having a sealing air supply/discharge mechanism in a cylinder capable of reducing the number of pressure stages of an air compressor to reduce its power consumption and improve engine output by compressing the air. It is.

[Means to solve the problem]

The internal combustion engine of the present invention having a sealing air supply/discharge mechanism in the cylinder is provided with an air supply hole in the cylinder liner surface located between the top ring and the second ring at the top dead center position of the piston. The present invention is applied to an internal combustion engine equipped with a high-pressure air supply device that supplies sealing air higher than the cylinder internal pressure between the two rings from the air supply hole.

Its characteristics are as shown in Figure 2.
An air supply valve 23 that intermittently supplies sealing air is connected to the air supply hole 19 described above. on the other hand,
An air exhaust hole 27 is formed in the cylinder liner surface located between the top ring 18A and the second ring 18B at a position near the bottom dead center of the piston 16. The air discharged outside the cylinder can be introduced into the primary side of the high-pressure air compressor 33 of the high-pressure air supply device 20 through the air discharge hole 27.

[Effect]

As the piston 16 approaches top dead center in the pre-combustion stage, the top ring 18A and second ring 18B
and reach a position where the air supply hole 19 is sandwiched between them. At this time, the air supply valve 23 opens, and sealing air with a pressure higher than the maximum pressure inside the cylinder stored in the high-pressure air supply device 20 flows from the air supply hole 19.
Supplied into the cylinder. At this time, the pressure between both rings further increases beyond the cylinder internal pressure, and the top ring 18A and the second ring 1
Sealing air leaks through 8B. Even if high-pressure air flows from the second ring 18B to the other piston rings 18 below, the pressure between those rings hardly decreases.

This supply of sealing air is continued even after combustion has started, and when the cylinder internal pressure reaches the maximum, the air supply valve 23 is closed and the supply of sealing air is stopped. Piston 1 due to expansion of combustion gas
6 falls, and both the cylinder internal pressure and the inter-ring pressure fall. When the piston 16 is near the bottom dead center, the top ring 18A and the second ring 18B
and reach a position sandwiching the air exhaust hole 27.
Then, the air between both rings is returned to the high-pressure air supply device 20 through the air exhaust hole 27, and the pressure between the rings approaches the pressure inside the cylinder.

The recovered air has a considerable residual pressure, and the first stage of the three- or four-stage high-pressure air compressor 33 becomes unnecessary, or its compression power is significantly reduced.

The air pressurized by the high-pressure air compressor 33 is then supplied between the rings again through the air supply hole 19 from the air supply valve 23, which is intermittently opened.

Incidentally, in the case of a 4-cycle engine, a check valve 28 is attached to the air exhaust hole 27, so that when the pressure of the air to be recovered becomes lower than the primary side pressure of the high-pressure air compressor 33 in the high-pressure air supply device 20. , backflow of air from the high-pressure air supply device 20 is prevented.

[Effect of idea]

According to the present invention, the high pressure air supplied near the top dead center of the piston is recovered near the bottom dead center.
The high pressure air supplied into the cylinder can be returned to the high pressure air supply device before it disappears. As a result, the power consumption in the primary compression stage of the high-pressure air compressor in the high-pressure air supply device can be significantly reduced. As a result, a decrease in engine output can be reduced, and combustion residues adhering to or remaining between the piston ring and the cylinder liner can be removed, and wear of the piston ring and the cylinder liner can be avoided.

If a check valve is provided in the passage connected to the air exhaust hole described above, it is possible to prevent backflow of air when the interring pressure at the air exhaust hole becomes lower than the discharge pressure of the high-pressure air supply device. can.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples thereof.

FIG. 2 shows an embodiment of an internal combustion engine 15 having a sealing air supply/discharge mechanism in the cylinder.
is a piston ring fitted onto the piston 16. Of the piston rings 18, 18A is a top ring, and 18B is a second ring.
Reference numeral 19 denotes an air supply hole opened in the cylinder liner 17 for supplying high pressure air from the high pressure air supply device 20 toward the piston 16 into the cylinder.

This air supply hole 19 is provided in the cylinder liner 17 located between the top ring 18A and the second ring 18B at the top dead center position of the piston 16. High pressure air supplied from the air supply hole 19 via the air supply valve 23 causes clean air to flow into the cylinder through the top ring 18A during the combustion stroke. Catalyst particles, combustion residue, and combustion gas present in the gap 21 between the top ring 18A and the side surface of the piston 16 above the top ring 18A and the inner surface of the cylinder liner 17 are pushed back into the combustion chamber 22 and are pushed back to the piston ring sliding surface. This prevents catalyst particles from entering. Note that the air supply valve 23 described above is controlled to intermittently supply air to the air supply hole 19. 24 is a solenoid valve that switches the supply and discharge of hydraulic oil to open and close the air supply valve 23; 25 is a hydraulic pressure generating device that generates hydraulic pressure; and 26 is a solenoid valve 24 that operates at a certain timing as the piston 16 reciprocates. This is a valve opening/closing control device that switches.

On the other hand, an air exhaust hole 27 is formed in the cylinder liner 17 located between the top ring 18A and the second ring 18B at a position near the bottom dead center of the piston 16. This air discharge hole 27 is provided with a check valve 28 that discharges air having a pressure equal to or higher than a set pressure from between the two rings. Although this check valve 28 may not be provided, the air pressure derived from the air discharge hole 27 is transferred to a high-pressure air compressor 33 (described later).
It is preferable to intervene so that only air having a set pressure or higher can be returned when the pressure becomes lower than the primary side pressure.

The high-pressure air supply device 20 includes 29 low-pressure air compressors, 30 low-pressure air storage tanks, 31 air coolers, 32 pressure regulating valves, 33 high-pressure air compressors,
It consists of 34 air coolers, 35 pressure regulating valves, 36 high-pressure air storage tanks, 37 safety valves, 38 lubricating devices, etc., and compressed air is supplied to the air supply valve 2.
3 to the air supply hole 19, while used sealing air from the air discharge hole 27 is collected. The recovered air is sent to a high pressure air compressor 33
is returned to the primary side. That is, the air is pressurized by the low-pressure air compressor 29 and introduced into the low-pressure air storage tank 30 in a storage state.

According to the configuration example described above, sealing air is supplied from the air supply hole 19 and recovered from the air discharge hole 27 in the following manner, thereby reducing power consumption in the high-pressure air compressor 33. can do.

To explain step by step, in the compression stroke, the top ring 18A is inserted into the ring groove 16 as shown in FIG.
A, and the air supply hole 19 is closed by the air supply valve 23. When the piston 16 approaches the top dead center at a stage before combustion, it reaches a position where the top ring 18A and the second ring 18B sandwich the air supply hole 19, as shown in FIG. 3b. The cylinder pressure up to this state is 4th
It rises as shown by the solid line in area A in the figure. At this point, the solenoid 24T is energized by the current from the valve opening/closing control device 26 to switch the port of the solenoid valve 24 to T, the hydraulic oil of the hydraulic pressure generator 25 is supplied to the air supply valve 23, and the air supply hole 19 is opened. Open your mouth.

Since the air pressure stored in the high-pressure air storage tank 36 is higher than the maximum pressure inside the cylinder, the piston 16 has risen to the top dead center.
High-pressure air is supplied from an air supply hole 19 between the top ring 18A and the second ring 18B that are fitted into the top ring 18A and the second ring 18B. And the top spring 18A is
As shown in FIG. 3c, it reaches the upper side of the ring groove 16A. At this time, the pressure between both rings further increases beyond the cylinder internal pressure in region B, as shown by the broken line in FIG. During this time, sealing air leaks through the top ring 18A and the second ring 18B, but even if it flows from the second ring 18B to the other piston rings 18C, 18D, and 18E, the pressure between these rings hardly decreases.

This sealing air supply continues even after combustion has started, and when the cylinder pressure reaches the maximum, the port of the solenoid valve 24 is switched to S by a command from the valve opening/closing control device 26, and the air supply valve 23 is closed and the supply of high pressure air is stopped. When the piston 16 descends due to the expansion of the combustion gas, the pressure inside the cylinder and the pressure between the rings decrease as shown in area C in FIG. 4, and when the state near the bottom dead center as shown in FIG. The second ring 18A and the second ring 18B reach a position where the air exhaust hole 27 is sandwiched between them. Then, the air between both rings is led out from the air discharge hole 27 to the low-pressure air storage tank 30 as shown in area D in FIG. 4, and approaches the cylinder internal pressure.

There is no problem if this air pressure is higher than the primary pressure of the high-pressure air compressor 33, that is, the discharge pressure of the low-pressure air compressor 29, but in cases such as the exhaust stroke of a 4-cycle engine, the inter-ring pressure is lower than that. Therefore, it is better to attach a check valve 28 to the air discharge hole 27 to prevent the air in the low-pressure air storage tank 30 from flowing back.

Since the pressure of the recovered air is higher than the newly pressurized outside air by the low-pressure air compressor 29, the first stage of the high-pressure air compressor 33, which usually consists of three or four stages, is no longer necessary, or Its compression power is significantly reduced. Note that the lack of air drawn out is compensated for by a low-pressure air compressor 29, mixed in a low-pressure air storage tank 30, cooled by an air cooler 31, and set to a certain pressure by a pressure regulating valve 32. The air is then introduced into the primary side of the high-pressure air compressor 33.

Air pressurized by the high-pressure air compressor 33 is cooled by an air cooler 34, adjusted to a constant pressure by a pressure regulating valve 35, and stored in a high-pressure air storage tank 36. Then, from the air supply valve 23 that opens intermittently, the air is passed through the air supply hole 19, and then the top ring 1
8A and the second ring 18B.

By the way, relatively high pressure is applied to the second ring 18B during the air supply stroke and the exhaust stroke, increasing the load on the ring. When the pressure between the rings is reduced by being discharged from the cylinder, the effect of reducing the load on each ring is also exhibited.

Although the above embodiments have mainly been explained using a four-stroke engine, they can be similarly applied to a two-stroke engine. Moreover, even if the above-mentioned air supply holes 19 and air discharge holes 27 are provided in an appropriate number around the cylinder liner 17, there is no difference in operation. Furthermore, when the check valve 28 is attached to the air discharge hole 27, the pressure of the air discharged to the outside of the cylinder may be adjusted using a mechanical cam mechanism or electrical control instead of the check valve. good.

As explained in detail above, the high-pressure sealing air supplied near the top dead center of the piston is recovered near the bottom dead center, so the sealing air supplied into the cylinder disappears as it is. It is possible to return the air to the high-pressure air supply device without any problems. In other words, most of the supplied high-pressure air leaks into the crank chamber through the rings below the second ring, and the remaining air leaks into the combustion chamber through the top ring. expansion,
The sealing air can be collected before disappearing through each ring during the four exhaust strokes.

As a result, power consumption in the primary compression stage of the high-pressure air compressor in the high-pressure air supply device can be eliminated or reduced. Therefore, a decrease in engine output can be reduced, and combustion residues that adhere or remain between the piston ring and the cylinder liner can be removed, and wear of the piston ring and cylinder liner can be avoided.

[Brief explanation of drawings]

Fig. 1 is a schematic system diagram of a piston for an internal combustion engine according to the prior art, Fig. 2 is a system diagram of an internal combustion engine having a sealing air supply/discharge mechanism in the cylinder of the present invention, and Fig. 3
Figures a to d are layout diagrams showing the positional relationship between the piston ring and the air supply hole or air discharge hole in each stroke, and Figure 4 is a pressure diagram comparing the cylinder internal pressure and the inter-ring pressure. 16... Piston, 17... Cylinder liner,
18...Piston ring, 18A...Top ring, 18B...Second ring, 19...Air supply hole, 20...High pressure air supply device, 23...Air supply valve, 27...Air discharge hole, 28... non-return valve,
33...High pressure air compressor.

Claims (1)

[Claims for Utility Model Registration] (1) An air supply hole is provided on the cylinder liner surface located between the top ring and the second ring at the top dead center position of the piston, and
In an internal combustion engine equipped with a high-pressure air supply device that supplies sealing air higher than the cylinder internal pressure between the two rings from the air supply hole, an air supply valve that intermittently supplies sealing air to the air supply hole. is connected, and an air exhaust hole is bored in the cylinder liner surface located between the two rings at a position near the bottom dead center of the piston, and the air discharged outside the cylinder through the air exhaust hole is discharged from the high pressure An internal combustion engine having a sealing air supply/discharge mechanism in a cylinder, characterized in that the air supply device can be introduced to the primary side of a high-pressure air compressor. (2) The cylinder according to claim 1 of the utility model registration claim, characterized in that the air discharge hole is provided with a check valve that discharges air having a pressure equal to or higher than a set pressure from between the two rings. An internal combustion engine with an air supply/exhaust mechanism for seals.