JPS58172431A - Variable compression ratio mechanism for internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce change-over time of compression ratio in a variable compression ratio mechanism having an eccentric bearing interposed between a piston pin and a smaller end of a connecting rod, by processing securely oil remaining forward of the moving direction of a lock pin in changing over of oil pressure for driving the lock pin. CONSTITUTION:A piston 1 is displaced relative to a connecting rod 3 by an eccentricity of an eccentric bearing 4 interposed between a piston pin 2 and a smaller end of said rod 3 to vary compression ratio. The eccenreic bearing 4 can be locked by the operation of a lock pin 6 received in a pressure house 5. The high compression ratio side 5a and low one 5b of the pressure chamber 5 communicate respectively to oil grooves 8a, 8b through oil paths 7, 9. The respective oil grooves 8a, 8b communicate alternatively to oil grooves 12a, 12b through an oil path 10a. And the respective grooves 12a, 12b are connected to bypass paths 24, 25 having solenoid valves 26, 27 interposed, and the respective valves 26, 27 are operated to open the paths 24, 25 to the atmosphere at the sides to which oil pressure for driving the lock pin is inoperative.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable compression ratio mechanism for an internal combustion engine in which an eccentric pairing is interposed between a piston pin and a small portion 111 of a connecting rod.

Conventionally, there has been a variable compression ratio mechanism in which the pressure width ratio of an internal combustion engine is changed by displacing a piston relative to a connecting rod by an amount of eccentricity of an eccentric bearing. In this variable compression ratio mechanism.

To switch between high compression ratio and low compression ratio, a locking pin attached to the connecting rod is inserted into and removed from a locking hole formed in the eccentric bearing, thereby controlling the rotating pipe of the eccentric bearing. ing. In order to switch to the high compression ratio side, when the lock bin is projected and fitted into the bin retaining hole of the eccentric bearing, oil is poured into the positive compression ratio side of the pressure chamber that is slidably installed inside the lock bin pipe. However, at this time, the oil that had flowed into the low compression ratio side of the pressure chamber is not immediately discharged, so the oil on the low compression ratio side acts as a resistance, causing a gap between the high compression ratio side and the low compression ratio side. However, a sufficient hydraulic pressure difference necessary for driving the lock bin cannot be obtained during this period, resulting in the disadvantage that the compression ratio cannot be switched reliably. Similarly, when switching to the low compression ratio side, the oil on the high compression ratio side of the pressure chamber is immediately turned off.
Therefore, the same drawback occurs in the switching K.

The object of the present invention is to reliably discharge the oil that acts as a resistance when driving the lock bin as described above, so that the compression ratio switching operation time can be significantly shortened and the internal combustion engine can be provided with high reliability. The purpose is to provide an eclipse compression ratio mechanism.

In the structure of the present invention, the pressure chamber is formed in the connecting rod and is equipped with a fully sliding automatic & rC, and the pressure chamber has oil branching paths for switching between high and low pressure knitting ratios on the compression ratio side, low pressure width ratio and W, respectively. communicate.

-The OT formed in the engine block is connected to the oil passages of the above-mentioned connecting rods through a single oil conduit pipe formed in the crankshaft for changing the compression ratio. In the transformer ratio 1a structure, the engine block V (one bypass passage is provided in each of the two front passages formed, and the oil passage on the side where the hydraulic pressure for driving the lock bin is not acting is a switching valve V attached thereto).
Therefore, the large AVc is naturally opened, and as a result, the oil in the pressure chamber on the side where the hydraulic pressure of the lock bin driver is not applied, the oil in the oil passage, and the oil in the oil passage are discharged as the crankshaft rotates, and the lock bin is released. There are things I did smoothly and reliably.

Embodiments of the present invention will be described based on the drawings.

Figures $1 to 1g5 show a first embodiment of the present invention. Small y of connecting rod 3 through piston IH piston pin 2
A single bearing 4 is installed in the s section, and is interposed between the piston pin 2 and the small St#As of the connecting rod 3. 4a shows a bottle retaining hole formed in the eccentric bearing 4. A pressure chamber 5 is formed in the internal Vc of the connecting rod 3, and is housed in a lock bin 6 so as to be able to freely slide within the pressure chamber 5. The continuous compression ratio side 5a of the pressure chamber 5 is connected to oil #1I18aV formed at the large end of the connecting rod 3 through seven oil passages.
c connected, one side of the pressure chamber 5 on the low compression ratio side 5bH oil passage 9
An oil groove sb formed at the large end of the connecting rod 30 through the
VC connected. The crankshaft 10rX and the large end rC of the connecting rod 3 are rotatably fitted together, and the end thereof is rotatably supported by the bearing section of the engine block 11. The bearing portion of the engine block 11 is provided with the aforementioned oil #8a.

8b [corresponding machine VC two oil grooves 12tL, 12
1) is formed. And among the crankshafts 10 @Kk1. These oil grooves ga, gb and 12a, 1
Oil passages IQa are formed which alternately connect the oil passages 2'b and 2'b.

Oil groove 12&t! The oil passage 13a, the main passage for high compression ratio 14h, are connected to the pressure switching valve 15 through the oil passage 13b, and the oil passage 18a, the main passage for low pressure ratio 17. Oil passage 161)? Through.

A pressure switching valve 15V'c is connected. Pressure switching valve 15
are oil passages 18a, 18b, 18C, and oil passages 19. It communicates with the oil 22 in the oil pan 21 via the Li-containing pipe 2D1. 23 is a mail flow passage, and an oil groove 121
Bypass passages 24.26 are connected to each of ゜12b K fl, and a solenoid valve 26.2 is connected to the bypass passage 24.25K.
7 are interposed respectively. The electromagnetic valves 26 and 27 are connected to the pressure switching valve 15 through lines 28 and 29k, and when the pressure switching valve 15 is in position LD, one is open [Fi], and the other is closed.

In the 11g3 diagram, 30c is the battery, 31tf ignition switch, a2 is the relay, 33 is the intake negative pressure switch, 34 is the intake boat, 35 is the intake valve, 38F! .

Exhaust valve and 37 cylinder head assembly are shown respectively.

The action and function will be explained below.

When the ignition switch is turned on, the pressure switching valve 15
is energized, the engine starts, and the pressure switching valve 1
5 is a working picture.

When the intake negative pressure switch blade detects the negative pressure state of the air-fuel mixture in the intake boat 34 and sends a signal to the pressure switching valve 15 to switch to a low compression ratio, the pressure switching valve 15 switches the oil to the low compression ratio main At the same time as switching to the passage 17, the solenoid valve of the bypass passage 24 opens, and the solenoid valve 27 becomes closed. Therefore, when the crankshaft is located at the position shown in FIG. 5, the oil passage 10a formed inside the crank shirt 10 connects the oil #I 12b and the oil groove 8b, and Pressure all the way through! !
! 5 low compression ratio 1115bK is about to flow in. That is, in this case, the low compression ratio m sb of the pressure chamber 5
tit constant pressure to pressure oysters? When the crankshaft rotates in the zero-order rotation that occurs and the oil passage 10a of the crankshaft 10 communicates with the oil #Sa in series with the oil groove 12a, the oil in the high compression ratio side of the pressure chamber 5 flows into the oil passage 7.
．． Oil #Isa, oil after passing 10k oil *1
Za Ka trying to do something. When C, bypass passage 2
Since the solenoid valve 26 of #4 is open to the atmosphere, oil #1
2affiK#1 oil is in the bypass passage 24. 0 is discharged into the oil pan 4 through a solenoid valve, then the crankshaft) 10 rotates, and the oil #lB1
21) and the oil sgb are reconnected, pressure oil is again supplied to the low compression ratio side of the pressure chamber 5, and furthermore, when the crankshaft 10 rotates and the oil fl112& and the oil @ are connected again, , high compression ratio in pressure chamber 5
Iktl is discharged into the oil pan 21 through the Ibus passage 24t. In this way, while the crankshaft rotates several times, the pressure power is 540gk, and the pressure ratio is 1li15.
bK Sufficient oil from the lid flows in, and the lock pin 6 is housed in the connecting rod and can be freely rotated in the single bearing position. In this way, the switching to the low compression ratio side is completed. In addition, the crankshaft 7) 100jffl rotational axis is given to the 5tIA middle ax-x@, and θ is the rotational axis of the crankshaft 10.

It shows the angle formed by the oil passage 10a. and.

AH, crank shirt) Indicates the direction of 100 rotations.

Next, the switching operation to the high compression ratio side will be explained.

The switching valve 15 is activated by the signal generated by the intake negative pressure switch 33.
When the switching valve 1511? switches and oil flows to the high compression ratio main passage 14, the switching valve 1511? : Interlockingly, bypass passage 24
The solenoid valve 26tl'i of the bypass passage 6 is closed, and the solenoid valve 27 of the bypass passage 6 is opened. Therefore, as the crankshaft 10 rotates, the oil groove 12 and the oil groove are connected by the oil passage lQa, and oil flows into the high compression ratio side 5a of the pressure chamber 5 through the oil passage 7, resulting in high pressure. Become. At this time, the oil in the low compression ratio side 5b of the pressure chamber 5 has the same pressure as the high compression ratio @5a, so it does not protrude into the lock bin 6 yet.

When the crankshaft 10 rotates by a certain angle and the oil passage 10a communicates with the oil groove 8b and the oil groove 12b as shown in FIG. Oil #8b, oil passage 10a, oil @ x
zb, bypass passage 25. It passes through the electromagnetic valve 27 to open to the atmosphere and is discharged into the oil pan 21. and.

Similar to the switching to the low compression ratio side described above, when the crankshaft 10 rotates several times, the high compression ratio side 5&K1-1.
Sufficient amount and pressure of oil will flow in, and the oil will be discharged from the low compression ratio side button, so the lock bin 6 will be smoothly and securely pulled out and the eccentric bearing 4's bin retaining hole pot It will be interlocked with. As a result, the switching operation to the high compression ratio side is completed.

Figure 1g6 shows a second example of the present invention.
5 t-exhaust, l & pressure compression ratio 7 冫7. Switching valve 1
The purpose is to switch all at once using the bypass passage installed in the 5 sections. As the switching valve 151. Rotary pulp can be used. Other operations are the same as those in Example IIi.

Figure 7 shows a practical example of the present invention, and the features of this embodiment are as follows. Embroidery example bypass passage 24.25
In the middle of the process, the oil pan 1i was removed from the solenoid valves 26 and 27.
In particular, a pump Pi is installed to forcibly discharge oil from the bypass passage on the side where the solenoid valve is open. The other operations are the same as in the previous example.

FIG. 8 shows a fourth embodiment of the present invention.The feature of this embodiment is that the bypass passage in the second embodiment is connected to the suction side of the outlet oil pump 19. This VC causes the oil to be forcibly discharged through the bypass passage aSt. Other operations are the same as in the second embodiment.

As explained above, according to the variable compression ratio mechanism for an internal combustion engine of the present invention, residual oil in the front of the lock bin moving direction can be reliably disposed of when switching between the high compression ratio side and the low compression ratio side. Therefore, the lock bin can be moved in and out in an extremely short time and reliably, and the switching of the compression ratio can be completed reliably in a short time.

Furthermore, since the present invention has an extremely simple configuration, it has high operational reliability and is highly effective in improving durability and overall performance of the engine.

[Brief explanation of drawings]

A sectional view of the main parts of the straw 11 variable compression ratio mechanism, Figure 2, is @1
FIG. 3 is a cross-sectional view taken along line 1-1 in the figure, and FIG. 3 is a cross-sectional view of the cylinder block portion of the variable compression ratio mechanism. Fig. 4 shows a partial oblique 1 (V) of the crankshaft, Fig. 6 is a perspective view showing the schematic structure of the present invention, Fig. 6 is a sectional view of the second embodiment O11 of the present invention, and Fig. 7 A sectional view of the main part of the second embodiment, and No. SSa is a sectional view of the main part of the fourth embodiment of the present invention. 1...e piston. 2... Piston pin. 3. 0. Connecting rod. No.: Fist, eccentric bearing. 5. Fist, pressure chamber. 1'. 6... Lock bin. 7. 9, 10a, 13a, 13b, 18a, 16b, 1
8a 5ees oil passage. 8a, 8b, 12a, 12b 5ees oil groove. 10...Crankshaft. 15...Switching valve. 24.25...Bypass passage. Shi, 27. War... Solenoid valve. 31φ...Ignition switch. Oh... Intake negative pressure switch. 34... Intake boat. Figure 1 8b! ■- ・1゜Figure 2

Claims (4)

[Claims] (1) Eccentricity between piston pin and connecting rod.
1111 is installed in the t alinder pipe and can be freely moved in and out of the connecting rod.
In the variable compression ratio mechanism for an internal combustion engine, in which the eccentric hair ring pipe can be fixed by a lock bin, one of the oil passages for high compression ratio and the oil passage for low compression ratio, which are mutually stand-alone, is used to drive the lock bin marked #. A piper passage is provided in each of the oil passages, and of the oil passage, only the bypass passage on the side on which the hydraulic pressure for driving the lock bin is not applied is opened to the atmosphere by a valve attached thereto. Variable compression ratio mechanism. (2) The oil passage is formed in the connecting rod and the cylinder block, respectively, and the oil passage on the cylinder block side is connected to the oil passage on the cylinder block side through the single oil passage formed in the crank shirt. Interchange with the food route, 1
Claim 1, which is characterized by
Town transformation ratio machine fermentation of internal combustion engine described in section. (3) The HJ variable earth reduction ratio mechanism for an internal combustion engine according to claim 2, wherein a front δ pi bypass passage is formed in each of the oil passages on the cylinder block side. (4) The variable compression ratio mechanism for an internal combustion engine according to any one of claims 1 to 3, characterized in that a pump pipe is interposed in the bypass passage.