JP2019039338A - Piston slap reduction device - Google Patents

Abstract

To provide a piston slap reduction device that can reduce slap sound from a reciprocating engine.SOLUTION: A piston slap reduction device 1 includes: an oil groove 3 formed by being extended in an axial direction of a cylinder wall 2 in a position where an engine E emits slap sound; an oil outlet 4 formed by being opened inside the oil groove 3 and discharging oil O; and an oil supply device 5 for supplying the oil O to the oil outlet 4 when the slap sound is emitted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piston slap reducing device that reduces slap noise of a reciprocating engine.

  In the reciprocating engine, the connecting rod tilts as the crankshaft rotates. For this reason, the direction of movement of the piston is reversed, and each time the inclination direction of the connecting rod changes, the piston slightly swings around the piston pin.

Japanese Patent Laid-Open No. 04-231611 JP 2003-286816 A Japanese Patent Laying-Open No. 2015-124733 JP 2011-220151 A

  By the way, when the piston shifts from the compression stroke to the expansion stroke, the piston swings in a state of receiving a relatively large pressure from the combustion chamber. For this reason, when shifting from the compression stroke to the expansion stroke, the piston skirt is strongly struck against the cylinder wall on the thrust side, and a slap noise is generated.

  Accordingly, the present invention has been made in view of such circumstances, and an object thereof is to provide a piston slap reducing device capable of reducing the slap noise of a reciprocating engine.

According to one aspect of the present invention, an oil groove formed to extend in the axial direction on a cylinder wall at a position where a slap sound of a reciprocating engine is generated;
An oil outlet formed to open in the oil groove and for discharging oil;
An oil supply device that supplies oil to the oil outlet when the slap sound is emitted;
A piston slap reducing device is provided.

  Preferably, the oil supply device includes a hydraulic pressure source, a supply oil path that connects the hydraulic power source and the oil outlet, an electromagnetic valve that is provided in the supply oil path and opens and closes the supply oil path, and the slap sound. And a control device that opens the electromagnetic valve when the is emitted.

  Preferably, a groove seal portion for sealing the oil groove in the axial direction is formed on the piston ring of the reciprocating engine.

  Preferably, the oil groove is formed in a circular arc shape in cross section.

  A plurality of the oil outlets may be formed.

  According to the present invention, the slap sound of the reciprocating engine can be reduced.

It is a schematic explanatory drawing of the piston slap reduction apparatus which concerns on one embodiment of this invention. It is a perspective view of a cylinder wall. It is AA arrow sectional drawing of FIG. It is a diagram showing the on-off timing of a solenoid valve. It is a top view of a piston ring.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. For convenience of explanation, in this embodiment, the moving direction of the piston in the compression process is set to the upper side, and the opposite direction is set to the lower side. The engine has four cylinders, and all the cylinders have substantially the same structure. For this reason, the illustration and description are made for one cylinder, and the other cylinders are omitted.

  FIG. 1 is a schematic explanatory diagram of a piston slap reduction device 1. FIG. 2 is a perspective view of the cylinder wall 2 showing the oil groove 3 and the oil outlet 4 formed in the cylinder wall 2.

  As shown in the drawing, the engine E to which the piston slap reduction device 1 is applied is a compression ignition type internal combustion engine mounted on a vehicle, that is, a diesel engine. Engine E is an inline 4-cylinder engine. The engine E may be a reciprocating engine, and may be a spark ignition internal combustion engine, that is, a gasoline engine. Further, the cylinder arrangement type and the number of cylinders of the engine E are not limited to those described above. The engine E may be a single cylinder engine or a multi-cylinder engine.

  As shown in FIGS. 1, 2, and 3, the piston slap reducing device 1 includes an oil groove 3 that extends in the axial direction on the cylinder wall 2 at a position where the engine E generates a slap sound, And an oil outlet 4 for discharging the oil O, and an oil supply device 5 for supplying the oil O to the oil outlet 4 when a slap sound is generated.

  The cylinder wall 2 at the position where the slap is generated is the cylinder at the position where the piston skirt 6a collides with the piston skirt 6a when the piston 6 starts to move from the compression stroke to the expansion process. Wall 2. The cylinder wall 2 is composed of a cylinder liner and is formed in a cylindrical shape.

  The oil groove 3 is formed in the cylinder wall 2 of each cylinder and extends across both ends of the cylinder wall 2. The oil groove 3 is formed with a constant groove width W and groove depth D. Furthermore, the oil groove 3 is formed in a circular arc shape in cross section. The oil groove 3 may not extend between both ends of the cylinder wall 2. The oil groove 3 may have a rectangular cross section or may have another shape.

  The oil outlet 4 is formed in the oil groove 3 of each cylinder and is formed close to a position where a slap sound is generated. The oil outlet 4 is formed at the bottom 3 a of the oil groove 3.

  The oil supply device 5 generates a slap sound, a hydraulic pressure source 7, a supply oil path 8 connecting the hydraulic power source 7 and the oil outlet 4, an electromagnetic valve 9 provided in the supply oil path 8 to open and close the supply oil path 8. And a control device 10 for opening the electromagnetic valve 9 when the operation is performed.

  The hydraulic power source 7 is configured by a pump driven by power from the crankshaft 11.

  The supply oil path 8 includes a main oil path 8 a that connects the hydraulic power source 7 and the main gallery 12, and a terminal oil path 8 b that connects the main gallery 12 and the oil outlet 4. The terminal oil passage 8b is branched into four from the main gallery 12, and is connected to the oil outlet 4 of each cylinder. The basic oil passage 8a and the terminal oil passage 8b are formed in the cylinder block. The basic oil passage 8a and the terminal oil passage 8b may be configured by piping. When the engine E is not a four-cylinder engine, the number of the end oil passages 8b may be the same as the number of cylinders of the engine E.

  The solenoid valve 9 is provided in each terminal oil passage 8b. The electromagnetic valve 9 is formed so as to be fully open and fully closed.

  The control device 10 is composed of an engine control unit. A crank angle sensor 13 that detects the crank angle of the engine E is connected to the control device 10. The crank angle information from the crank angle sensor 13 is sequentially input to the control device 10. The crank angle information is used to measure the opening / closing timing of each electromagnetic valve 9.

  FIG. 4 is a diagram showing control performed on the electromagnetic valve 9. The crank angle in the figure indicates a case where the compression top dead center of an arbitrarily selected cylinder is 0 °. Therefore, in other cylinders whose crank phases are shifted by a predetermined angle, the compression top dead center, the first set angle α, and the second set angle β are also shifted by the predetermined angle. Hereinafter, the control of the electromagnetic valve 9 corresponding to the arbitrarily selected cylinder will be described, and the description of the control of the electromagnetic valve 9 corresponding to other cylinders will be omitted.

  As shown in FIG. 4, in the control device 10, the crank angle at which the electromagnetic valve 9 is to be opened is preset as the first set angle α, and the crank angle at which the solenoid valve 9 is to be closed is preset as the second set angle β. The first set angle α and the second set angle β are set for each cylinder. The control device 10 sequentially compares the current crank angle with the first set angle α and the second set angle β set for each cylinder, and controls the opening and closing of the electromagnetic valve 9 based on the comparison result.

  Specifically, the control device 10 issues an ON signal to the electromagnetic valve 9 to fully open the electromagnetic valve 9 when the crank angle reaches the first set angle α. Further, when the crank angle reaches the second set angle β, the control device 10 issues an OFF signal to the electromagnetic valve 9 to fully close the electromagnetic valve 9. For example, the first setting angle α is set to 10 °. The second setting angle β is set to 30 °. In addition, each said numerical value is an illustration to the last, and can be changed suitably.

  The first set angle α is set to be slightly smaller than the crank angle (hereinafter referred to as the collision angle) θ at the moment when the slap sound is generated. The second set angle β is set to be slightly larger than the collision angle θ. Thus, oil O can be filled between the piston skirt 6a and the cylinder wall 2 immediately before the piston skirt 6a collides with the cylinder wall 2, and the hydraulic pressure is continuously supplied until the aftermath of the collision is settled. be able to.

  As shown in FIG. 5, a groove seal portion 15 for sealing the oil groove 3 in the axial direction is formed in the piston ring 14 of each cylinder. The groove seal portion 15 is formed on the outer periphery of the piston ring 14 so as to protrude radially outward. The groove seal portion 15 is formed in substantially the same shape as the oil groove 3 and is fitted into the oil groove 3. In the illustrated example, the groove seal portion 15 is formed in all the piston rings 14, but is not limited thereto. The groove seal portion 15 may be formed on at least one or both of the top ring and the second ring.

  Next, the operation of this embodiment will be described.

  When the arbitrarily selected cylinder is in the compression stroke, the piston 6 of the cylinder receives an upward force from the connecting rod 16 inclined to the thrust side and a downward force from the intake air in the combustion chamber 17. Be raised. Thereafter, when shifting to the expansion stroke, the piston 6 receives an upward force from the connecting rod 16 inclined to the anti-thrust side and receives a downward force from the air-fuel mixture expanded in the combustion chamber 17. Be lowered. As a result, the piston 6 is vigorously rotated around the piston pin 18 so that the piston skirt 6a approaches the thrust side. At this time, the crank angle, that is, the collision angle θ is substantially constant.

  On the other hand, when the crank angle reaches the first set angle α, the control device 10 issues an ON signal to the electromagnetic valve 9 to fully open the electromagnetic valve 9. Thereby, the oil O is discharged from the oil outlet 4 as shown in FIG. The oil O discharge continues until the crank angle reaches the second set angle β. The oil O discharged from the oil outlet 4 expands in the vertical direction along the oil groove 3 and is injected between the piston 6 and the cylinder wall 2.

  Thereafter, the crank angle becomes the collision angle θ, and the piston skirt 6a is vigorously rotated toward the thrust side. However, oil O continues to be injected between the piston skirt 6 a and the cylinder wall 2. For this reason, the force with which the piston skirt 6a collides with the cylinder wall 2 is weakened immediately before the collision. And the slap sound is reduced (small).

  Thereafter, when the crank angle reaches the second set angle β, the control device 10 issues an OFF signal to the electromagnetic valve 9 to fully close the electromagnetic valve 9. Thereby, the discharge of the oil O stops.

  When the piston 6 is further lowered, the piston ring 14 scrapes off excess oil O between the piston 6 and the cylinder wall 2, and the groove seal portion 15 scrapes off the oil O in the oil groove 3. For this reason, the oil O discharged from the oil outlet 4 can be prevented or suppressed from entering the combustion chamber 17.

  As described above, the piston slap reducing device 1 discharges the oil O formed in the oil groove 3 that is formed to extend in the axial direction on the cylinder wall 2 at the position where the slap noise is generated and the oil groove 3 that opens. The oil outlet 4 and an oil supply device 5 that supplies oil O to the oil outlet 4 when a slap sound is generated are provided. For this reason, when the piston 6 collides with the cylinder wall 2, the oil O can be interposed between the piston 6 and the cylinder wall 2, and the slap noise can be reduced efficiently.

  The oil supply device 5 includes a hydraulic pressure source 7, a supply oil path 8 that connects the hydraulic power source 7 and the oil outlet 4, an electromagnetic valve 9 that is provided in the supply oil path 8 and opens and closes the supply oil path 8, and a slap sound. And a control device 10 that opens the electromagnetic valve 9 when the mist is emitted. For this reason, oil O can be supplied reliably and the supply timing of oil O can be set optimally.

  The piston ring 14 is provided with a groove seal portion 15 for sealing the oil groove 3 in the axial direction. For this reason, the oil O discharged from the oil outlet 4 can be prevented or suppressed from entering the combustion chamber 17.

  Further, since the oil groove 3 is formed in a circular arc shape, the groove seal portion 15 of the piston ring 14 can be smoothly slid relative to the oil groove 3.

  As mentioned above, although embodiment of this invention was described in detail, the following other embodiments are also possible for this invention.

  (1) A plurality of oil outlets 4 may be formed in the oil groove 3. In this case, the oil outlet 4 may be formed on the bottom 3 a of the oil groove 3 so as to be separated in the vertical direction. The oil O can be spread over a wider range, and the collision between the cylinder wall 2 and the piston skirt 6a can be alleviated.

  (2) Although the solenoid valve 9 is formed so as to be fully open and fully closed, it is not limited thereto. For example, the solenoid valve 9 may be a half-openable valve in addition to a fully open fully closed state. In this case, the control device 10 fully opens the solenoid valve 9 when the crank angle reaches the first set angle α, and half opens the solenoid valve 9 when the crank angle reaches the second set angle β. The solenoid valve 9 may be fully closed when the groove seal portion 15 located at the lowest position approaches the oil outlet 4. According to this, the oil O can be sufficiently supplied into the cylinder, and the lubricity of the cylinder wall 2 and the piston 6 can be improved.

  (3) Although the supply oil passage 8 passes through the main gallery 12, the oil pressure source 7 and the oil outlet 4 may be connected without passing through the main gallery 12. In this case, the main oil passage 8a may be branched into a plurality of terminal oil passages 8b.

  (4) The groove seal 15 may be omitted when oil leakage into the combustion chamber 17 can be substantially ignored, such as when the amount of oil O leaking from the oil groove 3 into the combustion chamber 17 is very small.

  The configurations of the above-described embodiments can be combined partially or wholly unless there is a particular contradiction. The embodiment of the present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

1 Piston Slap Reduction Device 2 Cylinder Wall 3 Oil Groove 4 Oil Outlet 5 Oil Supply Device 6 Piston E Engine O Oil

Claims (5)

An oil groove formed in the cylinder wall extending in the axial direction at a position where the slap sound of the reciprocating engine is emitted;
An oil outlet formed to open in the oil groove and for discharging oil;
An oil supply device that supplies oil to the oil outlet when the slap sound is emitted;
A piston slap reduction device comprising: The oil supply device is
A hydraulic source;
A supply oil path connecting the hydraulic pressure source and the oil outlet;
An electromagnetic valve provided in the supply oil passage for opening and closing the supply oil passage;
A control device that opens the solenoid valve when the slap sound is emitted;
The piston slap reduction device according to claim 1, comprising: The piston slap reduction device according to claim 1 or 2, wherein a groove seal portion for sealing the oil groove in the axial direction is formed in a piston ring of the reciprocating engine. The piston slap reducing device according to any one of claims 1 to 3, wherein the oil groove is formed in an arc shape in cross section. The piston slap reduction device according to any one of claims 1 to 4, wherein a plurality of the oil outlets are formed.

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