JPS6024414B2 - Piston friction force measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston friction force measurement device for a reciprocating internal combustion engine, and in particular to a piston friction force measurement device that allows the friction force between a piston and a cylinder to be actually measured during engine operation. Concerning a measuring device.

Reducing friction loss in internal combustion engines is one important item for energy conservation. However, the conventional measurement of friction loss is
The only methods available are the motoring method or the difference between the indicated output and the shaft output, and in both cases, the measured value is the total average value of one cycle, and it shows the friction of each friction part over time, which has an important meaning for reducing friction loss. The course of force is unknown, and it has not been effective in providing accurate measures for reducing friction loss. Therefore, the inventors have focused on developing a method and apparatus for actually measuring the frictional force between the piston and the cylinder, which occupies an important part of the frictional parts of the entire engine, during engine operation. As a result, the present invention has been completed as a device that almost achieves the objective. This method basically measures the force on the cylinder due to the frictional force of the piston, and therefore the cylinder must be separated from the cylinder block and cylinder head and supported by a pickup.

Therefore, the following problems arise. '1} Seal the working gas in the cylinder so that it does not affect the frictional force waveform. '21 To prevent the movement of the head caused by the gas pressure inside the cylinder and the resulting deformation of the upper part of the block from affecting the friction waveform.

'3' Prevent the impact of the piston wrap from affecting the friction force waveform.

The present invention has been made to eliminate the drawbacks of the prior art described above and to solve the measurement problems described above. An object of the present invention is to provide a piston friction force measurement device that can accurately and easily measure actual piston friction force during engine operation, and in particular, to seal the gas pressure in the cylinder so as not to affect the friction force waveform during the combustion stroke. It is.

In short, the present invention supports a cylinder so that it can be displaced relative to a cylinder block, and a displacement detection device that detects the relative displacement is installed between the cylinder and the cylinder block.
A ○ ring holder that holds a ○ ring for sealing the upper part of the cylinder is fixed to the cylinder block and separated from the cylinder head, and a groove for accommodating the ○ ring is formed across both the inner wall of the cylinder and the ○ ring holder. a ○ ring is accommodated in the groove, a space is provided between the O-ring holder and the cylinder head that passes through the cylinder, and a heat-resistant seal ring is attached to the outer periphery of the space;
The pressure-receiving areas in the vertical direction of the cylinder and the ○ ring holder on which the gas pressure in the cylinder acts are made equal, so that the acting force due to the gas pressure acting on the cylinder and cylinder block is equal in three directions in the vertical direction. It is characterized by:

The present invention will be explained below based on embodiments shown in the drawings.

FIG. 1 is an assembly diagram of a piston friction force measuring device 1 according to the present invention, in which one end of the rocking stops such as 2 and 3 is fixed to a cylinder 4, and the other end is fixed to a cylinder block 5.
The outer end 2a of the cylinder block 5 is fixed to the cylinder block 5 and is attached to one end 6a of a cylinder 6 that protrudes laterally via an elastic body 7. As a result, the cylinder 4 is supported so as to be movable relative to the cylinder block 5. It has been done. Also this cylinder 4 and cylinder tab. The pickup, which is a displacement detection device for measuring the relative displacement between the pickup and the pick 5, needs to increase the natural frequency of the measurement system in order to accurately measure the frictional force during high-speed rotation. It must be possible to detect cylinder displacement. Therefore, a piezo type pickup is adopted as the displacement detection device 8, and a front load bolt 9 is screwed onto the cylinder block 5 at the lower end 4a of the zero cylinder 4, and a pickup presser is fixed to the lower end 4a of the cylinder 4. The pickup 8 is fixed by being sandwiched between the pickup 10 and the pickup 10. Next, during operation of the engine, the gas seal that acts within the cylinder 4 has a structure as shown in the upper part of FIG. 1 and an enlarged view of this part in FIG. 2.

That is, in order to seal the upper part 4b of the cylinder 4, an O-ring 11 is used, and an O-ring holder 12 that holds this O-ring 11 is fixed to the cylinder block 5 with bolts 13 and separated from the cylinder head 15. be. On the other hand, the cylinder head 15 is fixed to the cylinder block 5 with ordinary bolts (not shown), and using these bolts as a spring system, the cylinder head 15 is displaced by gas pressure independently of the ring holder 12. There is. A groove 14 for accommodating the o-ring 11 is provided across both the inner wall 4c of the cylinder and the o-ring holder 12, and has the same depth b.

That is, the center 16 of the groove 14 that accommodates the O-ring 11 is aligned with the inner wall 4c of the cylinder 4, the O-ring 11 is accommodated here, and a gap 17 is formed between the cylinder 4 and the O-ring holder 2. ing. Furthermore, a space 18 is provided between the O-ring holder 12 and the cylinder head 15 to fit the cylinder 4, and a heat-resistant seal ring 19 is attached to the outer circumference 18a of the space. uses an annular metal ring with a dogleg-shaped cross section, and the inner maximum diameter part 19a of this ring 19
is aligned with the inner wall 4c of the cylinder 4, that is, the sliding surface of the piston 20 and the center 16 of the groove 14.

As a result, the pressure receiving area A in the vertical direction of the cylinder 4 and the ○ ring holder I2 on which the gas pressure in the cylinder 4 acts
u and Ao become equal. In other words, ○ located inside cylinder 4
If the width of the portion 12a of the ring holder 12 is C, then the pressure receiving area AU where the gas pressure acts upward as shown by the arrow 21 as shown in the third figure is equal to the width 10 C and the average circumference of this portion.
Since the pressure-receiving area Ao where the gas pressure acts downward as shown by the arrow 22 is also the product of 10C and the average circumference of this part, they are equal. Therefore, regardless of the magnitude of the gas pressure, the force exerted by the gas pressure Z on the cylinder 4 and the cylinder block 12 is configured to be equal in the vertical direction. The top land 20a of the piston 20 is cut off by a length h from the upper end 20b and a length d from the outer periphery 20c in the radial direction to prevent the Z piston 20 from interfering with the O-ring holder 12.

In the piston 20, 23, 24, and 25 are piston rings for compression, and 26 is a piston ring for oil. Also, cylinder 4 and cylinder block 12
○ rings 27 for sealing are arranged at four locations between the two. Note that 28 is a passage for cooling water. The present invention is constructed as described above, and its operation will be explained below.

When the engine is started, the piston 20 reciprocates in the vertical direction, and due to the friction between the piston rings 23 to 26 and the inner wall 4c of the cylinder 4, the cylinder 4 is displaced relative to the cylinder block 5. The pickup 8 detects displacement forgery. Moreover, this displacement layer is proportional to the magnitude of the frictional force. Note that, at this time, the swing stops 2 and 3 effectively act to prevent the piston 20 from swinging. Next, a case will be explained in which the pressure of the gas in the silica cylinder 4 increases rapidly during the combustion stroke of the engine.As shown in FIG. Through cylinder 4 and ○ ring holder 1
Press upward the upper surface of the groove 14 provided between the
Then, the lower end of the portion 12a of the O-ring holder 12 is similarly pressed upward as indicated by the arrow 21.

Therefore, if the gas pressure in the cylinder 4 is P, the upward acting force Fu is the product of P and the pressure receiving area AU. On the other hand, regarding the same downward acting force Fo, as shown by the arrow 22, it presses the lower end of the groove 14 on the side of the cylinder 4, and also presses the lower end of the groove 14 on the side of the ○ ring holder 12, that is, the groove From the center 16 of 14, press the right part in the figure downward as shown by arrow 22. In this case, the downward acting force Fo is the product of the pressure P and the pressure receiving area Ao. However, as mentioned above, in the device of the present invention, the pressure receiving areas AU and Ao
Since they are made equal, the vertical acting forces FU and Fo due to the gas pressure are equal, and as a result, Schilling 4 and ○
The ring holder 12 is not displaced in either the up or down direction depending on the gas pressure in the cylinder 4, and the pressure waveform detected by the pickup 8 is not affected, allowing only the frictional force to be detected. Note that a large upward force acts on the cylinder head 15 each time combustion occurs, but since the O-ring holder 12 is not attached to the cylinder head 15 and is separated from it, the effect of the vertical vibration of the cylinder head 15 is suppressed. I won't even receive it.

Further, the O-ring holder 12 is provided with a cooling water passage 28, and since the cooling water 29 flows therethrough, the holder does not overheat.

The gas inside the cylinder 4 is completely sealed by the O-ring 11 and the metal ring 19, and measurements can be carried out satisfactorily. Next, the results of measuring the frictional force between the piston 20 and the cylinder 4 using the device 1 of the present invention will be explained.

When measuring frictional force, the value is extremely sensitively affected by oil temperature, so it is inappropriate to use cooling water temperature as the standard when comparing frictional force during actual operation and motoring.
The temperature of the cylinder wall was measured at three locations: top dead center (TDC), bottom dead center (BDC), and center of the top ring, and the temperature at the center position was used as a reference. Here, what Furuhama and Suzuki are using in this research (Shoichi Furuhama, Hidekazu Suzuki; Transactions of the Japan Society of Mechanical Engineers Vol. 45, No. 392, 197
9, P. According to the results of measuring the temperature of the cylinder and ring in an engine almost the same as 571), the sliding surface temperature of the piston ring varies from 15qo to 20qo depending on the temperature of the cylinder.
o I know it's expensive. On the other hand, in the case of a motor ring, the piston ring and cylinder temperatures are considered to be approximately the same temperature. Therefore, in an experiment to estimate the frictional force of the ring during actual operation, we thought that the closest value would be to measure the temperature of the cylinder wall at a temperature 8 to 1000 times higher than the temperature during actual operation, and that method was adopted. The engine used in the experiment was a single-cylinder test engine with a bore of 13
7 guys, stroke: 135 side, direct injection 4-stroke diesel engine, 3 compression rings, 1 oil ring
This is a book ring arrangement. Next, an example of the measurement results is shown below.
Figure 4 shows an example of measuring the frictional force in a firing ring, where F is the frictional force waveform, P is the pressure fluctuation inside the cylinder 4, and the rotation angle (o) of the crankshaft is
, and the top dead center in the combustion stroke is set to 00.

The vertical axis shows the frictional force (k9) and the pressure inside cylinder 4 (a blood).
I'm taking it. The engine speed was kept constant at 120 pm and the cooling water temperature was varied. In this figure tw'
tc is the cooling water temperature, and tc indicates the temperature at the top ring position at the center of the stroke of the cylinder 4. That is, as shown in the figure, the waveform of the frictional force F has almost no noise and is clearly drawn, and as the cooling water temperature tw increases, the frictional force F increases.
can clearly be seen to decrease. Figure 5 shows the maximum value F of the frictional force in the intake and exhaust strokes for each cooling water temperature of 8w based on the results in Figure 4.

and the maximum value Fm of the frictional force during the combustion stroke, respectively. As shown in this figure, it has become clear that the cylinder wall temperature has a large effect on the frictional force, and that particularly large frictional forces are exhibited at low temperatures and when the viscosity of the lubricating oil is high. In addition to the above-mentioned measurements, the device of the present invention measures changes in frictional force when changing the rotational speed, changes in frictional force when changing piston rings, changes in frictional force during one rotation of the crankshaft, and various parts for the total frictional force. It is possible to easily measure the magnitude of the three contribution factors for both firing and motoring. Since the present invention is configured and operates as described above, it is possible to accurately and easily measure the frictional force between the piston and cylinder of a reciprocating internal combustion engine even during engine operation, which has been difficult with the prior art. In particular, it has the effect of sealing the gas pressure inside the cylinder so that it does not affect the frictional force waveform during the combustion stroke, and it can reduce the magnitude of the frictional force in each part of the internal combustion engine. By making it possible to actually measure friction, this invention can contribute to the development of low-friction engines, and is an extremely excellent invention for promoting energy savings in internal combustion engines.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the assembled state of the device of the present invention, Fig. 2 is an enlarged longitudinal sectional view of the main part, Fig. 3 is a longitudinal sectional view of the main part showing the operating state of the cylinder internal pressure, and Fig. 4 is the main part. A diagram showing the results of actual measurements of the frictional force of the piston during engine operation using the invented device at various cooling water temperatures. Figure 5 is a diagram created based on the results in Figure 4. FIG. 2 is a diagram plotting changes in frictional force with respect to water temperature. 1 is a piston friction force measuring device, 4 is a cylinder, 4c is an inner wall of the cylinder, 5 is a cylinder block, 8 is a piezo type pickup which is an example of a displacement measuring device, 11 is a circle, 12 is an O ring holder, 14 is a circle Ring housing groove, 1
5 is the cylinder head, 16 is the center of the housing groove 14 of the ○ ring, 18 is the space, 18a is the outer periphery of the space, 19 is a metal ring as an example of a heat-resistant seal ring, and 19a is the maximum inner diameter of the ring. 20 is a piston. Figure 4 Figure 1 Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] 1. A cylinder is supported so as to be movable relative to a cylinder block, a displacement detection device for detecting the relative displacement is installed between the cylinder and the cylinder block, and an O-ring is provided to seal the top of the cylinder. An O-ring holder to be held is fixed to the cylinder block and separated from the cylinder head, a groove for accommodating the O-ring is provided across both the inner wall of the cylinder and the O-ring holder, and an O-ring is inserted into the groove.
A space is provided between the O-ring holder and the cylinder head to accommodate the ring and communicate with the inside of the cylinder, and a heat-resistant seal ring is attached to the outer periphery of the space, so that the gas pressure inside the cylinder acts on the cylinder and A piston friction force measuring device characterized in that the pressure receiving area of the O-ring holder in the vertical direction is equalized so that the acting force due to the gas pressure acting on the cylinder and the cylinder block is equal in the vertical direction. 2. The center of the groove that accommodates the O-ring is aligned with the inner wall of the cylinder, and the inner maximum diameter part of the heat-resistant seal ring is aligned with the inner wall of the cylinder to equalize the pressure receiving area in the vertical direction. A piston friction force measuring device according to claim 1. 3. The piston friction force measuring device according to claim 1 or 2, wherein the heat-resistant seal ring is an annular metal ring having a dogleg-shaped cross section. 4. The piston friction force measuring device according to any one of claims 1 to 3, wherein the displacement detecting device is a piezo pickup.