JP5146100B2 - Engine cylinder device - Google Patents

Description

  The present invention relates to an engine cylinder device.

  In an engine cylinder device of an internal combustion engine in which a piston reciprocates along a cylinder liner, by supplying lubricating oil to a sliding surface on which the piston of the cylinder liner slides, a predetermined thickness is provided in the gap between the cylinder liner and the piston. The oil film is formed so that the cylinder liner and the piston can slide smoothly, and the occurrence of piston seizure, cylinder liner wear, and the like can be avoided.

In an engine cylinder device, the thickness of the oil film of lubricating oil is an indicator of the likelihood of seizure or the like, so a film thickness detection sensor for detecting the thickness of the oil film is provided on the cylinder liner so as to face the piston. It is known that a device for detecting the oil film thickness and adjusting the supply amount of the lubricating oil based on the detection result is provided.
As such an engine cylinder device, for example, in Patent Document 1, an electrode sensor provided on a cylinder liner and a piston ring of a piston are opposed to each other, and a capacitance between the electrode sensor and the piston is detected. What is provided with the oil film measuring device which measures the thickness of the formed oil film is disclosed.
JP 2007-107947 A

  By the way, in the engine cylinder device, as many film thickness detection sensors as possible are arranged evenly in the stroke direction and the circumferential direction of the cylinder liner so as to prevent detection leakage such as seizure. For example, the engine cylinder device disclosed in Patent Document 1 is actually provided with about 40 total film thickness detection sensors evenly, and the number of film thickness detection sensors is enormous, resulting in high costs. The problem was occurring.

  The present invention has been made in view of the above problems, and provides an engine cylinder device that can prevent detection leakage such as piston burn-in and can reduce the cost of providing a film thickness detection sensor. With the goal.

In order to solve the above problems, the present invention provides a piston connected to a crank mechanism and reciprocally movable along a cylinder liner, the cylinder liner provided at the cylinder liner and facing the piston, and the piston An engine cylinder device comprising a plurality of film thickness detection sensors for detecting the thickness of an oil film of lubricating oil formed in a gap with the piston, wherein the film thickness detection sensor changes the speed of the piston that changes due to the reciprocating movement. Accordingly, a configuration is adopted in which the number provided at a predetermined position in the reciprocating direction is different.
By adopting such a configuration, in the present invention, the film thickness detection sensor is arranged according to the characteristic that the easiness of seizure or the like in the reciprocating direction varies depending on the speed of the piston. The film thickness detection sensor can be effectively arranged at a position where it easily occurs.

In the present invention, the film thickness detection sensor is configured to be disposed at the predetermined position at least on both sides in a direction substantially orthogonal to the rotational axis direction of the crank mechanism and the reciprocating direction.
By adopting such a configuration, in the present invention, the film thickness detection sensor is arranged according to the characteristic that the piston is likely to be seized in the orthogonal direction in which the piston applies a load to the cylinder liner. The film thickness detection sensor can be effectively arranged at an easy position.

Further, in the present invention, the predetermined position corresponds to a top dead center position corresponding to the top dead center of the piston and a position where an oil supply port for supplying the lubricating oil to a sliding surface on which the piston slides is provided. And a scavenging port position corresponding to the position of the scavenging port provided near the bottom dead center of the piston, and a midstroke position located between the top dead center position and the scavenging port position. The configuration is adopted.
By adopting such a configuration, in the present invention, the film thickness detection sensors are arranged at the top dead center position, the lubrication port position, the scavenging port position, and the mid stroke position, which are likely to be seized in the reciprocating direction. Thus, detection omission such as burn-in can be suppressed.

In the present invention, the number of the film thickness detection sensors provided at the mid stroke position is greater than the number of the film thickness detection sensors provided at the top dead center position, the oil supply port position, and the scavenging port position. However, the configuration of a small number is adopted.
By adopting such a configuration, according to the present invention, the number of film thickness detection sensors can be reduced by reducing the number of film thickness detection sensors according to the characteristic that seizure or the like is less likely to occur at the mid-stroke position than at other positions. Reduction can be achieved.

According to the present invention, a piston connected to a crank mechanism and reciprocally movable along a cylinder liner, and provided in the cylinder liner, is formed in a gap between the cylinder liner and the piston at a position facing the piston. An engine cylinder device comprising a plurality of film thickness detection sensors for detecting the thickness of the oil film of the lubricating oil, wherein the film thickness detection sensor reciprocates according to the speed of the piston that changes due to the reciprocation. By adopting a configuration in which the number provided at a predetermined position in the direction is different, the film thickness is detected according to the characteristic that the seizure in the reciprocating direction differs depending on the piston speed. By disposing the sensor, the film thickness detection sensor can be effectively disposed at a position where burn-in or the like is likely to occur. In other words, according to the present invention, the film thickness detection sensors are arranged according to the characteristics of easiness of seizure or the like, so that many film thickness detection sensors are not arranged on the cylinder liner evenly as in the prior art. Detection leakage such as piston seizure can be prevented.
Therefore, the present invention has an effect of providing an engine cylinder device that can prevent detection leakage such as piston burn-in and can reduce the cost of providing a film thickness detection sensor.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a functional configuration diagram of an engine cylinder device E according to an embodiment of the present invention. As shown in this figure, the engine cylinder device E has an engine cylinder S and a film thickness measuring device M.
The engine cylinder S is, for example, a cylinder of a two-cycle engine, and includes a piston P, a cylinder liner s1, and a crankshaft (crank mechanism) K as illustrated.

The piston P is connected to the crankshaft K via the piston rod p2, and is configured to be reciprocally movable along the cylinder liner s1. The piston P has a piston ring p1, and the piston ring p1 slides along the piston sliding surface s3. In addition, in this embodiment, although it has the structure which has one piston ring p1 for ease of explanation, the structure with two or more piston rings p1 may be sufficient.
The cylinder liner s1 includes a sensor head mounting hole s2, a piston sliding surface (sliding surface) s3, and an oil supply port s4, a scavenging port s5, and an exhaust port s6 not shown in FIG. 1 (see FIG. 3). ing. Note that a plurality of lubrication ports s4 are provided near the top dead center of the piston P and in the circumferential direction of the cylinder liner s1.
The crankshaft K has a base end portion that is rotatable about a rotation axis extending in a direction perpendicular to the paper surface in FIG. 1, and a distal end portion is connected to the piston rod p2 so as to be rotatable about a rotation axis extending in the same direction.

  The film thickness measuring device M includes a sensor head (film thickness detection sensor) 1, a coaxial cable 2, a capacitance detection unit 3, a cylinder pressure detection unit 4, a crank angle detection unit 5, and a signal processing unit 6. . Such a film thickness measuring device M is formed in the gap between the cylinder liner s1 and the piston P in the engine cylinder S, more specifically, in the gap between the inner wall surface (piston sliding surface s3) of the cylinder liner s1 and the piston ring p1. The thickness of the lubricating oil film is measured.

  The sensor head 1 has a structure in which a cylindrical sensor electrode is concentrically covered with an insulating material, and the outer periphery of the insulating material is concentrically covered with a conductor sensor case. Such a sensor head 1 is press-fitted into the sensor mounting hole s2 so as to be flush with the piston sliding surface s3. When facing the piston ring p1, the sensor head 1 forms a capacitor (measurement capacitor) having the piston ring p1 as a counter electrode and an oil film as a dielectric. The sensor head 1 is connected to a capacitance detection unit 3 (specifically, a capacitance detection amplifier 3a) via a coaxial cable 2. One end of the braided wire forming the shield layer of the coaxial cable 2 is connected to the sensor case of the sensor head 1, and the other end is connected to the grounding portion (GND: ground) of the capacitance detection unit 3.

The capacitance detection unit 3 includes a capacitance detection amplifier 3a, a voltage / current converter 3b, an AC / DC power source 3c, and a shield case 3d.
The capacitance detection amplifier 3a supplies a constant current to the sensor head 1 via the coaxial cable 2, and detects the capacitance of the measurement capacitor based on a change in the charging voltage of the measurement capacitor charged by the constant current. Then, the voltage signal d1 (analog signal) indicating the capacitance is output to the voltage / current converter 3b. The voltage / current converter 3b converts the voltage signal d1 input from the capacitance detection amplifier 3a into a current signal d2, and outputs the current signal d2 to the signal processing unit 6 (specifically, the current / voltage converter 6a).

  The AC / DC power supply 3c converts the AC power supplied from the outside into a direct current and supplies it to the capacitance detection amplifier 3a and the voltage / current converter 3b. The common terminal of the AC / DC power source 3c is connected to the shield case 3d. The shield case 3d is an electromagnetic shielding housing that houses the capacitance detection amplifier 3a, the voltage / current converter 3b, and the AC / DC power source 3c, and is externally grounded.

The cylinder pressure detector 4 detects the pressure in the combustion chamber of the engine cylinder S, and outputs a pressure signal indicating the pressure to the signal processor 6 (specifically, the film thickness calculator 6c).
The crank angle detection unit 5 is, for example, an encoder, detects the rotation angle of the crankshaft K, that is, the crankshaft, and outputs a rotation angle signal indicating the rotation angle to the signal processing unit 6 (specifically, the film thickness calculation unit 6c). Output to. The rotation angle of the crankshaft indicates the position of the piston ring p1 with respect to the piston sliding direction.

The signal processing unit 6 includes a current / voltage converter 6a, an A / D converter 6b, a film thickness calculation unit 6c, and a display unit 6d.
In the signal processing unit 6, the current / voltage converter 6a converts the current signal d2 input from the voltage / current converter 3b of the capacitance detection unit 3 into a voltage signal d3 and converts it to the A / D converter 6b. Output. The A / D converter 6b converts the voltage signal d3, which is an analog signal, into a digital signal d4 and outputs the digital signal d4 to the film thickness calculator 6c.

  The film thickness calculation unit 6c is input from the digital signal d4 (that is, electrostatic capacity) input from the A / D converter 6b, the pressure signal input from the cylinder pressure detection unit 4, and the crank angle detection unit 5. By performing predetermined signal processing on the rotation angle signal, the film thickness of the oil film formed in the gap between the piston ring p1 and the sensor head 1 is calculated, and a film thickness signal indicating the film thickness is output to the display unit 6d. . The display unit 6d is a liquid crystal display device, for example, and displays film thickness information based on the film thickness signal.

Next, the arrangement of the sensor head 1 in the engine cylinder device E configured as described above will be described with reference to FIGS. 2 and 3.
FIG. 2 is a development view of the cylinder liner s1 in the embodiment of the present invention.
FIG. 3 is a cross-sectional view of the engine cylinder S in the embodiment of the present invention.
2, the front side of the cylinder liner s1 in FIG. 1 is 0 degree (in the direction of the rotation axis of the crank mechanism), the right side is 90 degrees, the back side is 180 degrees (in the direction of the rotation axis of the crank mechanism), and the left side Is shown as 270 degrees.

As shown in FIGS. 2 and 3, the sensor heads 1 are arranged with different numbers provided at predetermined positions in the reciprocating direction of the piston P according to the speed of the piston P that changes due to the reciprocating movement. Specifically, in the present embodiment, as shown in FIG. 2, a plurality of sensor heads 1 are provided at a top dead center position, a lubrication port position, a scavenging port position, and a midstroke position, which are predetermined positions in the reciprocating direction. Yes.
In FIG. 3, the top dead center position is indicated by k1, the lubrication port position is k2, the scavenging port position is k3, and the midstroke position is indicated by k4.

  The top dead center position k1 is a position corresponding to the top dead center of the piston P. In the present embodiment, as shown in FIG. 3, when the piston P is located at the top dead center, the position facing the piston ring p1 It has become. At the top dead center position k1, as shown in FIG. 2, four sensor heads 1 are arranged at equal intervals in the circumferential direction of the cylinder liner s1, at positions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees. Yes.

  The oil supply port position k2 is a position corresponding to the position where the oil supply port s4 for supplying the lubricating oil to the piston sliding surface s3 is provided. In this embodiment, as shown in FIG. 3, the oil supply port s4 and the top dead center are provided. The position is near the position k1 and below the top dead center position k1. At the lubrication port position k2, as shown in FIG. 2, four sensor heads 1 are arranged at equal intervals in the circumferential direction of the cylinder liner s1, at positions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees. Yes.

  The scavenging port position k3 is a position corresponding to the position of the scavenging port s5 provided near the bottom dead center of the piston P. In the present embodiment, as shown in FIG. 3, the scavenging port position k3 is a position near the scavenging port s5. . At the scavenging port position k3, as shown in FIG. 2, a total of four sensor heads 1 are arranged at positions of 0 degrees, 90 degrees, 180 degrees and 270 degrees at equal intervals in the circumferential direction of the cylinder liner s1. Yes.

  The mid stroke position k4 is a substantially intermediate position between the top dead center position k1 and the scavenging port position k3. In the present embodiment, as shown in FIG. 3, the relative angle between the crankshaft K and the piston rod p2 is set. When the angle becomes approximately 90 degrees, the position is opposite to the piston ring p1. At the mid-stroke position k4, as shown in FIG. 2, a total of two sensor heads 1 are arranged at positions of 90 degrees and 270 degrees in the circumferential direction of the cylinder liner s1.

Next, the grounds and operation of arranging the sensor head 1 as described above at the top dead center position k1, the oil supply port position k2, the scavenging port position k3, and the midstroke position k4 will be described.
As is well known, the engine cylinder S repeats a cycle including a compression process, an explosion process, an exhaust process, and a scavenging / intake process, and the piston P reciprocates in the cylinder liner s1 in accordance with these processes. When the piston P reciprocates, the moving direction is changed in the opposite direction at the top dead center and the bottom dead center, so that the speed of the piston P decreases near the top dead center position k1 and the scavenging port position k3. . On the other hand, the speed of the piston P at the mid stroke position k4 is larger than the speeds at the top dead center position k1 and the scavenging port position k3. In the experiment, a result that seizure of the piston P is likely to occur at a position where the speed of the piston P is low (top dead center position k1 and scavenging port position k3) is obtained.
Further, the position where seizure or the like is likely to occur in the circumferential direction of the cylinder liner s1 is a position in the direction in which the piston P applies a load to the cylinder liner s1, and more specifically, the rotational axis direction of the crankshaft K and the piston. Experimental results have been obtained that indicate positions on both sides in the orthogonal direction substantially perpendicular to the reciprocating direction of P (positions of 90 degrees and 270 degrees in FIG. 2).

  These experimental results are supported by the Stribeck curve showing the relationship between friction and lubrication. As is well known, the Stribeck curve is shown in a graph in which the vertical axis represents the coefficient of friction and the horizontal axis represents the Sommerfeld number having parameters of viscosity × speed ÷ load dimensions. In the Stribeck curve, when the Sommerfeld number is large, the solid and the solid are separated by a continuous oil film and fluid lubrication slides smoothly. On the other hand, when the Sommerfeld number is small, the solid and solid are separated. Has been shown to result in mixed lubrication with partial solid contact.

That is, the speed of the piston P changes due to the reciprocating movement, but as indicated by the Stribeck curve, the Sommerfeld number increases as the speed increases, and the oil film in which the cylinder liner s1 and the piston P are continuous is obtained. Since the fluid lubrication is smoothly separated and separated, seizure hardly occurs.On the other hand, in the vicinity of the top dead center and the bottom dead center, the speed is temporarily reduced by changing the moving direction, so the Sommerfeld number is As a result, the cylinder liner and the s1 piston P are partially mixed in solid contact, and seizure is likely to occur.
Further, since the load from the piston P is applied to the positions on both sides in the orthogonal direction of the cylinder liner s1 more than the other positions in the circumferential direction, the Sommerfeld number is reduced, and the cylinder liner and the s1 piston P partially Since mixed lubrication in contact with the solid can occur, seizure tends to occur.

That is, at the top dead center position k1, the speed of the reciprocating piston P is small, so that there is a characteristic that seizure or the like is likely to occur.
Further, since the lubricating oil is sequentially supplied from the lubricating port s4 at the lubricating port position k2, the thickness of the oil film is likely to fluctuate, and furthermore, the position where the lubricating port s4 is provided is near the top dead center. Etc. are likely to occur.
Further, since the combustion air-fuel mixture flows into the engine cylinder S at the scavenging port position k3, the oil film may be lost due to the inflow of the air-fuel mixture and the thickness may be reduced. Since it is in the vicinity, the speed of the piston P is small, and there is a characteristic that seizure or the like is likely to occur.
Further, at the mid stroke position k4, the speed of the reciprocating piston P is high, and there is a characteristic that seizure or the like is less likely to occur compared to other positions.

  Therefore, the sensor head 1 is mainly arranged at the top dead center position k1, the lubrication port position k2, and the scavenging port position k3 in the vicinity of the top dead center and the bottom dead center, and the top dead center position k1 at the mid stroke position k4. Even if the number of the sensor heads 1 is small from the lubrication port position k2 and the scavenging port position k3, it becomes possible to sufficiently detect seizure or the like.

Therefore, according to the above-described embodiment, the piston P is connected to the crankshaft K via the piston rod p2, and is reciprocally movable along the cylinder liner s1, and the cylinder liner s1, and faces the piston P. The engine cylinder device E includes a plurality of sensor heads 1 for detecting the thickness of the oil film of the lubricating oil formed in the gap between the cylinder liner s1 and the piston P at the position, and the sensor head 1 is changed by the reciprocation. By adopting a configuration in which the number provided at a predetermined position in the reciprocating movement direction is changed according to the speed of the piston P to be moved, the reciprocating movement is performed according to the relative speed between the piston P and the cylinder liner s1. The sensor head 1 is arranged in accordance with the characteristic that easiness of image sticking in the direction is different. , It can be arranged effectively sensor head 1 to easily position the burn or the like occurs. In other words, in the present embodiment, the sensor heads 1 are arranged according to the characteristics of easiness of seizure or the like, so that many sensor heads 1 are not arranged on the cylinder liner s1 evenly as in the prior art. Detection leakage such as seizure of the piston P can be prevented.
Therefore, this embodiment has an effect of providing an engine cylinder device E that can prevent detection leakage such as seizure of the piston P and can reduce the cost of providing the sensor head 1.

  Further, in the present embodiment, the sensor head 1 employs a configuration in which the sensor head 1 is disposed at positions on both sides in the orthogonal direction substantially orthogonal to the rotation axis direction of the crankshaft K and the reciprocating movement direction at the predetermined position. By arranging the sensor head 1 according to the characteristic that the piston P tends to be seized in the orthogonal direction in which the piston P applies a load to the cylinder liner s1, the sensor head 1 is effectively arranged at a position where seizure or the like is likely to occur. can do.

  In the present embodiment, the predetermined position is provided with a top dead center position k1 corresponding to the top dead center of the piston P and an oil supply port s4 for supplying lubricating oil to the piston sliding surface s3 on which the piston P slides. Between the lubrication port position k2 corresponding to the position to be removed, the scavenging port position k3 corresponding to the position of the scavenging port s5 provided in the vicinity of the bottom dead center of the piston P, and the scavenging port position k3. By adopting a configuration that includes a mid-stroke position k4 that is positioned, the sensor head is located at the top dead center position k1, the lubrication port position k2, the scavenging port position k3, and the mid-stroke position k4, which are likely to be seized in the reciprocating direction. By arranging 1, it is possible to suppress detection omission such as burn-in.

  In the present embodiment, the number of sensor heads 1 provided at the mid stroke position k4 is smaller than the number of sensor heads 1 provided at the top dead center position k1, the lubrication port position k2, and the scavenging port position k3. By adopting such a configuration, it is possible to reduce the cost by reducing the number of sensor heads 1 provided at the mid-stroke position k4 according to the characteristic that seizure or the like is less likely to occur compared to other positions. Can do.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the present embodiment, four sensor heads 1 are disposed at each of the top dead center position k1, the lubrication port position k2, and the scavenging port position k3, and two sensor heads 1 are disposed at the mid stroke position k4. The present invention is not limited to the above number. For example, the number of sensor heads 1 provided at each position may be doubled.

It is a functional lineblock diagram of an engine cylinder device in an embodiment of the invention. It is an expanded view of the cylinder liner in embodiment of this invention. It is sectional drawing of the engine cylinder in embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sensor head (film thickness detection sensor), E ... Engine cylinder apparatus, K ... Crankshaft (crank mechanism), P ... Piston, k1 ... Top dead center position, k2 ... Lubrication port position, k3 ... Scavenging port position, k4 ... Mid stroke position, s1 ... Cylinder liner, s3 ... Piston sliding surface (sliding surface), s4 ... Lubrication port, s5 ... Scavenging port

Claims (2)

A piston connected to a crank mechanism and reciprocally movable along a cylinder liner; and an oil film of lubricating oil provided in the cylinder liner and formed in a gap between the cylinder liner and the piston at a position facing the piston. An engine cylinder device comprising a plurality of film thickness detection sensors for detecting thickness,
The film thickness detection sensor is disposed at a predetermined position in the reciprocating direction at least at positions on both sides of the direction of the rotation axis of the crank mechanism and the direction substantially orthogonal to the reciprocating direction.
The predetermined position is
A top dead center position corresponding to the top dead center of the piston; and
A scavenging port position corresponding to a scavenging port position provided near the bottom dead center of the piston; and
A mid-stroke position located between the top dead center position and the scavenging port position; and
An oil supply port position corresponding to a position on the top dead center side of the piston with respect to the mid stroke position and corresponding to a position where an oil supply port for supplying the lubricating oil is provided on a sliding surface on which the piston slides;
Number the thickness detection sensor, said one of the speed of the piston which changes by the reciprocating movement, which depending on the speed of the piston moving from the mid-stroke position to the top dead center side of the piston, is provided at the predetermined position An engine cylinder device characterized by being arranged differently. The number provided at the mid-stroke position of the film thickness detection sensor is smaller than the number provided at the top dead center position, the oil supply port position, and the scavenging port position of the film thickness detection sensor. The engine cylinder device according to claim 1 .

Images