JPS6118961B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for measuring the amount of wear on piston rings in various internal combustion engines such as diesel engines and gasoline engines. In order to monitor the wear status of piston rings in various internal combustion engines such as diesel engines, when metal is brought close to the electromagnetic field created by a coil under current,
Piston ring wear is measured using an electromagnetic sensor that utilizes the principle of electromagnetic induction in which the impedance of the coil and the phase difference between current and voltage change. To explain using a diagram, a cylinder 6 is composed of a cylinder liner 1 and a cylinder block 2, and houses a piston 5 having piston rings 3 and 4, and a sensor 7 for monitoring piston rings is installed in the cylinder 6.
In order to avoid the influence of the harsh atmosphere of the engine combustion chamber, a sleeve 8 is attached to the cylinder liner 1 as shown in the figure, which allows the sensor 7
and the combustion chamber. In order to monitor the wear state in this way, a conventional method has been to monitor the maximum wear point. That is, piston rings 3, 4
Of these, only the top ring 3 is plated with chrome at the part indicated by 9, and when measured by the sensor 7, if the top ring 3 is not worn, it is shown in Figure 1 B.
As shown by V ₁ , only the plating portion becomes smaller than the signal V ₂ of the other ring 4 . As the engine wears down gradually due to engine use,
When the value of V ₁ approaches V ₂ and the chrome plating 9 is completely worn out, the signal V ₂ of the other ring 4 and C
are equal as shown in . Therefore, by setting the chrome plating layer to the maximum wear point in advance, the maximum wear point can be detected. However, such conventional methods require plating on the top ring, which lacks versatility, and the maximum plating layer that can be processed is only about 0.4 mm, so the maximum wear amount required for practical purposes is 3 mm.
The disadvantage is that it cannot be detected. Maintenance work on diesel engines is carried out on a regular basis, and even if some parts are due to be serviced during maintenance work, other parts may still be in good condition. This results in unnecessary engine disassembly. On the other hand, if an abnormality in the combustion chamber of the engine during operation is not detected early, this abnormality will rapidly lead to damage and breakage of the main parts of the engine, or lead to uneconomical fuel consumption. Therefore,
In order to eliminate these problems, it is necessary to directly obtain data for preventive maintenance of the engine at all times while the engine is in operation. Even if the piston ring wears, the cylinder inner diameter remains almost constant, and since the piston ring is pressed against the cylinder by a spring action, the piston ring outer diameter remains constant, so when the piston ring wears, the piston ring The width of the joint will be expanded. Therefore, the present invention measures the amount of wear on the piston ring by detecting the width of the abutment of the piston ring, and quantitatively measures the amount of wear no matter what material the piston is made of, as long as it is a magnetic metal. The purpose is to obtain. The structure of the present invention that achieves the above object is a method of measuring the wear amount of a piston ring fitted on the circumferential surface of a piston reciprocating in a cylinder from the width of a piston ring abutment. In addition, the width of the piston ring abutment is measured by an electromagnetic sensor having a detection surface approximately equal in size to the predicted maximum width of the piston ring abutment, and the signal pattern obtained by the electromagnetic sensor is a positive pulse signal, a positive pulse signal, and a positive pulse signal. The wear amount of the piston ring is measured by determining whether the piston ring belongs to a double pulse signal or a composite signal of a positive double pulse signal and a negative pulse signal. Next, referring to an embodiment of the present invention, an electromagnetic sensor 7 is attached to the cylinder liner 1 as in the case of FIG. 1, so that the piston ring 3 is constantly monitored. The size of the detection surface of the electromagnetic sensor 7 is approximately equal to the expected maximum width of the piston ring abutment.
Further, the combustion chamber and the sensor 7 are partitioned off by a sleeve 8. J in Fig. 3 is a scanner, which selects the number of channels according to the number of cylinders to be monitored, and from there the signal is sent to the signal conditioner K, where it is processed, and sent through the interface L to the processing system micro A signal is transmitted to computer M. At this time, the final signal evaluation is performed by the processing system microcomputer M.
However, abnormality determination of the piston ring 3 is evaluated based on the signal pattern obtained from the normal piston ring 3 part and the signal pattern obtained from the width of the abutment part 10 of the piston ring 3. In other words, the signal pattern shown in FIG. 5A is a pattern indicating a normal ring, FIG. This shows the signal pattern. In the figure, OV indicates the case where the side surface of the piston other than the piston ring and piston ring groove is detected, and the above signal pattern is expressed based on this. The signal pattern described above also differs depending on the width of the abutment portion 10 when the sensor detects the abutment portion 10, and the width D of the abutment portion 10 has a certain relationship with the amount of wear of the piston ring as described above. There is. The relationship is shown in the tables. The dimensions of each specification shown in Figure 2 are exemplified for three models of diesel engines A, B, and C. As shown in the table, the width of the joint and the width of the joint for these three models are as shown in the table. The relationship with wear is shown in the table. All numerical values in the table and inside are in mm. Therefore, if the width D of the abutment portion 10 can be measured, the amount of wear of the piston ring can be calculated from this value. During operation, the piston ring constantly rotates around the piston within the ring groove, and the piston does not necessarily reciprocate with the center of the piston aligned with the center of the cylinder, but rather is offset or eccentric. In addition to the above rotation, the ring height, that is, the radial distance between the piston ring and the piston at the front surface of the sensor changes at the same time. Therefore, as described above, FIG.
Various signal patterns as shown in C can be obtained, and they also differ depending on the width of the abutment, that is, the state of wear of the piston ring. Showing this, the 6th
As the piston ring wear increases, a positive pulse signal as shown in FIG. 6A, a positive double pulse signal as shown in FIG. 6B, and a positive double pulse signal as shown in FIG. 6C. Three patterns of composite pulse signals of a positive double pulse signal and a negative pulse signal as shown are obtained. The peak value (indicated by p in the figure) of each signal becomes smaller as the width of the abutment portion 10 increases, since the metal portion facing the sensor detection surface can be reduced. For example, if the signal obtained by the width of the normal abutment part 10 (Fig. 6A) is set to 1.0 volts (V) (can be set to any value by adjusting the sensitivity), the signal will spread slightly. The peak value in the case of the signal obtained by the abutment width (FIG. 6B) is 0.95 volts, and the peak value for the signal obtained by the even wider abutment width (FIG. 6C) is about 0.8 volts. Furthermore, the amount of drop (indicated by d in the figure) with respect to the peak value increases as the abutment width increases, and in the signal shown in Figure 6C, the minimum value of the drop is smaller than the reference value OV. This state is called a negative signal. The above three signal patterns are shown in FIG. 7 in relation to the ring wear amount depending on the ring height. In FIG. 7, the area below the solid line is the area of the positive pulse signal shown in FIG. 6A,
The area between the broken line and the solid line is the area of the positive double pulse signal shown in FIG. 6B, and the area above the broken line is the area of the 6th pulse signal.
This is the area of the composite pulse signal shown in Figure C. In this way, since there is a certain relationship between the amount of ring wear and the signal pattern of the abutment part 10 obtained by the sensor, the wear state of the piston ring can be detected by measuring the abutment part with the sensor. . The positive pulse signal shown in FIG. 6A indicates a ring wear amount of 0 to 1.1 mm, and the positive double pulse signal shown in FIG. 6B indicates a ring wear amount of 0.5 to 3.0 mm.
The composite pulse signal shown in Figure 6C shows the amount of ring wear.
It means 1.8mm or less. Therefore,
If the signal pattern obtained by the sensor is a positive pulse signal shown below the solid line in FIG. 6A, that is, in FIG. 7, it can be detected that the amount of wear of the piston ring is 0 to 1.1 mm. This data is obtained by measuring the width of the abutment using a single sensor, and the measurement accuracy is relatively poor. Therefore, when two sensors 7a and 7b are attached to the cylinder 6 facing each other as shown in FIG. Measurements can be made with higher accuracy. In this method, if the width signal of the abutment 10 is obtained from either sensor 7a or 7b,
The other sensor measures the piston ring at a location 180 degrees away from the abutment 10, and as shown in Figure 8, the piston ring height at that location can be measured from the output voltage obtained from the other sensor. . As shown in Fig. 4, if the cylinder inner diameter is _{D1 and} the piston outer diameter is _D2 , the maximum gap between the cylinder and the piston is S= _D1 - _D2 , and S
Since =S ₁ +S ₂ , the ring height of the abutment portion 10 can be determined from the ring height obtained by the other sensor. For example, the sensor 7a
Assuming that a width signal of 2 is captured, S ₂ can be determined from FIG. 8 from the output of the sensor 7b. As a result, S ₁ is calculated. For example, if S ₁ is 1.5mm,
From FIG. 7, the amount of ring wear meant by the signal pattern indicating the width of each abutment part can be understood. At this time, the positive pulse signal has a wear amount of 0 to 1 mm, the positive double pulse signal has a wear amount of 1 to 2.6 mm, and the composite pulse signal of the positive double pulse signal and negative pulse signal has a wear amount of 2.6 mm. This means that the ring wear amount can be detected with higher accuracy than when using a single sensor. For example, at this time, if a positive double pulse signal is obtained by the sensor 7a, the ring wear amount is in the range of 1 to 2.6 mm. According to the present invention, the amount of ring wear can be detected using a signal indicating the width of the piston ring abutment using a sensor, so that the life range of piston rings in various internal combustion engines such as diesel engines can be constantly monitored. , preventive maintenance becomes possible. In addition, the need for engine maintenance and inspection can be constantly grasped, unnecessary engine disassembly can be prevented, and inspection can be carried out in a timely manner, and furthermore, it is possible to save operating costs by early detection of engine abnormalities.

【table】

【table】 [Brief explanation of the drawing]

Figure 1A is a cross-sectional view showing the sensor installed in the cylinder, Figures 1B and C are graphs showing the conventional piston ring wear measurement method, and Figure 2A, B, and C are engine specifications. Explanatory diagram showing the third
The figure is a block diagram showing a measurement circuit according to the measurement method of the present invention, Figure 4 is a plan view showing a method for measuring ring wear using two sensors, and Figures 5A, B, and C are typical signal patterns by the sensors. Figures 6A, B, and C are graphs showing the relationship between the width of the abutment and the signal pattern by the sensor when the sensor detects the abutment, and Figure 7 is the relationship between the ring height and the ring height. A graph showing the relationship between the amount of wear and the signal pattern, and FIG. 8 is a graph showing the change in signal level depending on the ring height. In the drawings, 1 is a cylinder liner, 2 is a cylinder block, 3 and 4 are piston rings, 5 is a piston, 7 is a sensor, and 10 is an abutment.

Claims (1)

[Claims] 1 A method of measuring the wear amount of a piston ring fitted on the circumferential surface of a piston reciprocating in a cylinder from the width of the piston ring abutment, which is the maximum width of the piston ring abutment provided on the cylinder side and predicted. The width of the abutment of the piston ring is measured by an electromagnetic sensor that has a detection surface approximately equal in size to the width of the piston ring, and the signal patterns obtained by the electromagnetic sensor are positive pulse signal, positive double pulse signal, and positive double pulse signal. A piston ring wear measuring method characterized in that the wear amount of a piston ring is measured by determining which of a composite signal of a negative pulse signal and a negative pulse signal it belongs to.