JPH0447374Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine lubrication device, and particularly to a lubrication device aimed at reducing engine friction loss.

[Prior art] Generally speaking, lowering the viscosity of lubricating oil for engines is effective in reducing engine friction, but in valve train systems where lubrication conditions are severe, lowering the viscosity of lubricating oil promotes boundary lubrication and reduces friction. The problem is that losses increase. This tendency is particularly noticeable in the low rotation range.

As a solution to this problem, the engine's lubrication path is divided into the valve train system and other parts of the crankshaft system, etc.
A lubricating device has been proposed in which an oil cooler is installed in the lubrication path of the valve train to increase the viscosity of the lubricating oil sent to the valve train, thereby reducing friction loss in the valve train. 1986-135312, Utility Model Application No. 57-92812, Utility Model Application No. 58-6908).

[Problems to be solved by the invention] However, in the conventional technology as described above,
Since accessories such as oil coolers are used under all operating conditions, they are effective in low rotation ranges where friction loss increases, but in high rotation ranges where this is not a problem, oil pump losses due to high viscosity of lubricating oil occur. The problem is that the engine's friction reduction effect is diminished.

In other words, as shown in Fig. 6, which shows an example of the relationship between engine speed and friction loss torque, boundary lubrication in the valve train is avoided in the low engine speed range by increasing the viscosity of the lubricating oil. Friction loss is reduced, but in the high rotation range, the relative speed between the two contacting objects in the valve train increases, and the rotation speed of the oil pump increases, resulting in an increase in the amount of oil supplied.
It was found that the lubrication conditions of the valve train system have been improved from the severe conditions, and there is no longer a large difference in the lubrication conditions between high-viscosity and low-viscosity lubricants, and that low-viscosity lubricants actually reduce engine friction loss.

Focusing on the above test results, the present invention adjusts the viscosity of the lubricating oil sent to the valve train according to the engine speed, ensuring good lubrication of the valve train while maintaining a high level of lubricating oil throughout the entire rotation range. The purpose is to reduce engine friction loss.

[Means for Solving the Problems] The engine lubrication device of the present invention that meets this objective has a lubrication path that is divided into a sub-lubrication path that supplies lubricant to the engine's valve train and a sub-lubrication path that supplies lubricant to other parts of the engine. In an engine lubricating system configured with a main lubricating path, an oil cooler is provided in the sub-lubricating path, and a bypass passage that sends lubricating oil to the valve train without going through the oil cooler is connected to the sub-lubricating path. The lubrication path is equipped with a control valve that sends lubricating oil to the valve train system via an oil cooler in low engine speed ranges, and sends lubricant oil to the valve train system via the bypass passage in high engine speed ranges. It consists of

[Operation] In such an engine lubricating device, in the low engine speed range, the valve train is supplied with high viscosity lubricating oil cooled by the oil cooler. Therefore, a sufficient oil film is ensured in the lubricated portion of the valve train, and boundary lubrication is avoided, and an increase in engine friction loss due to boundary lubrication is suppressed.

On the other hand, in the high speed range of the engine, lubricating oil is sent to the valve train only through the bypass passage without going through the oil cooler by switching the control valve. Therefore, in the high rotation range of the engine, relatively high temperature and low viscosity lubricating oil is sent to the valve train. In the high engine rotation range, the oil pump rotation speed also increases, so a sufficient amount of lubricating oil is supplied, and the relative speed between the two objects in contact with the lubricating oil is also large, so the lubrication of the valve train is maintained. is kept in good condition. In addition, in the high engine speed range,
Since the lubricating oil is not forced to cool, the viscosity of the lubricating oil is maintained low, reducing losses in the oil pump and suppressing increases in frictional losses throughout the engine.

[Embodiments] Hereinafter, preferred embodiments of the engine lubricating device of the present invention will be described with reference to the drawings.

1 to 3 show an engine lubricating device according to a first embodiment of the present invention. As shown in FIG. 1, the lubrication path is composed of a main lubrication path 1 that sends lubricant to the crankshaft system of the engine, and a sub-lubrication path 2 that sends lubricant to the valve train of the engine.

The main lubrication path 1 includes an oil pump 5 that pumps lubricant oil sucked up from an oil pan 3 through an oil strainer 4, and sends the lubricant oil to a main oil hole 7 via an oil filter 6. 7, a crankshaft 8, a connecting rod 9, and a piston 10 are lubricated, and then the lubricating oil is returned to the oil pan 3. The sub-lubricating path 2 consists of a path that sends lubricating oil from the main oil hole 7 to the valve train, such as the camshaft 11, the rocker arm 12, and the valve 13, and returns it to the oil pan 3.

A control valve 17 is connected to the sub-lubrication path 2 that sends lubricant oil from the main wheel hole 7 to the valve train system.
is provided. The control valve 17 is connected to a bypass passage 16 and a lubricating oil cooling passage 15 that sends lubricating oil supplied from the main oil hole 7 to the valve train system. Lubricating oil cooling passage 15
An oil cooler 14 for forcibly cooling the lubricating oil from the main oil hole 7 is arranged. The control valve 17 sends lubricating oil to the camshaft 11, which is a valve train, through the lubricating oil cooling passage 15 in which the oil cooler 14 is arranged in the low engine speed range, and sends lubricating oil only to the bypass passage 16 in the high engine speed range. Camshaft 1, which is the valve train,
It has the function of sending lubricating oil to 1.

The control valve 17 is shown in FIGS.
It is configured as shown in the figure. Spring 18
A piston 19 is provided which is biased to one side by a main oil hole 7.
An oil passage 21 is formed in which the lubricant cooling passage 15 and the bypass passage 16 can communicate with either one depending on the position of the piston 19.

The structure of this control valve is, for example,
A second embodiment shown in FIGS. 4 and 5 may be used. In the control valve 22 of this embodiment, the piston 24 biased by the spring 23 is moved according to the oil pressure of the oil passage 25 connected to the main oil hole 7, and is connected to the lubricating oil cooling passage 15 and the bypass passage 16. Leading opening/closing part 2
Either 6 or 27 can be opened.

The operation of the engine lubrication system configured as described above will be explained below.

The lubricating oil pressure-fed from the main oil hole 7 is selectively sent to the lubricating oil cooling passage 15 and the bypass passage 16 depending on the engine speed. In the low rotation range, the rotation speed of the oil pump 5 is low and the hydraulic pressure of the lubricating oil being pumped is low, so the biasing force of the springs 18, 23 exceeds the hydraulic pressure, and the pistons 19, 24 move as shown in FIGS. 2 and 4. It will be in the position shown. Therefore, the lubricating oil flows through the lubricating oil cooling passage 15.
The oil is sent to the valve train via the oil cooler 14. By being cooled by the oil cooler 14, highly viscous lubricating oil is sent to the valve train, thereby avoiding boundary lubrication and reducing friction loss.

When the engine reaches a high speed range, the oil pump 5
As the rotational speed increases and the oil pressure for pumping lubricating oil also increases, the oil pressure overcomes the biasing force of the springs 18 and 23, and the pistons 19 and 24 are at the positions shown in FIGS. 3 and 5. Therefore, the lubricating oil is sent to the bypass passage 16 and sent to the valve train without going through the oil cooler 14. By not passing the lubricating oil through the oil cooler 14, relatively high temperature and low viscosity lubricating oil is sent to the valve train. Since the rotation speed of the oil pump 5 is increasing, a sufficient amount of lubricating oil is sent to the lubricating parts of the valve train, and the relative speed between the two contacting objects is large enough, so that the required oil film is is formed and maintained in a well-lubricated state. In addition, in the high speed range of the engine, the lubricating oil returned to the oil pan 3 and pumped from the oil pan 3 is kept at a low viscosity, so the increase in loss in the oil pump 5 is suppressed, and the friction loss of the entire engine is kept low. It can be suppressed.

[Effects of the invention] As explained above, when using the engine lubrication device according to the invention, the sub-lubrication path that sends the lubricant to the valve train has a control that switches the flow path of the lubricant depending on the level of the engine speed. The provision of a valve allows high viscosity lubricating oil that is forcibly cooled by the oil cooler to be sent to the valve train in the low engine speed range, ensuring a sufficient oil film on the lubricated parts of the valve train. can do. Therefore,
Boundary lubrication is avoided, and an increase in engine friction loss can be suppressed.

In addition, in the high speed range of the engine, a large amount of low-viscosity lubricating oil is sent to the valve train through the bypass passage that bypasses the oil cooler, so the valve train can maintain good lubrication. Increase in pump loss can be suppressed.

In this way, it is possible to suppress an increase in the friction loss of the entire engine in all rotation ranges, and by reducing the friction loss, it is possible to achieve the effect that fuel efficiency and output can be improved.

[Brief explanation of drawings]

Fig. 1 is a lubrication system diagram of the engine lubricating device of the present invention, Fig. 2 is a sectional view of the control valve according to the first embodiment of the present invention, and Fig. 3 is another operating state of the control valve of Fig. 2. 4th cross-sectional view showing
The figure is a sectional view of a control valve according to a second embodiment of the present invention, FIG. 5 is a sectional view showing another operating state of the control valve of FIG. 4, and FIG. 6 is an engine speed, friction loss torque, and lubrication. This is a relationship diagram with the viscosity of oil. 1...Main lubrication route, 2...Sub lubrication route,
3...Oil pan, 5...Oil pump, 7...
Main oil hole, 14...Oil cooler, 1
6... Bypass passage, 17, 22... Control valve, 18, 23... Spring, 19, 2
4... Piston.

Claims (1)

[Scope of utility model registration request] In an engine lubricating device in which a lubrication path is configured with a sub-lubrication path that sends lubricant oil to a valve train of the engine and a main lubrication path that sends lubricant oil to other parts of the engine, an oil cooler is provided in the sub-lubrication path, A bypass passage that sends lubricating oil to the valve train without going through the oil cooler is connected to the sub-lubrication path, and lubricating oil is sent to the valve train through the oil cooler in the low engine speed range to the sub-lubrication path. A lubricating device for an engine, characterized in that a control valve is provided that sends lubricating oil to the valve train through the bypass passage in a high engine speed range.