JP3117758B2 - Lubricating oil supply device for two-cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil supply device for a two-stroke engine, and more particularly to an improved control method for controlling the amount of lubricating oil supplied to the engine to an appropriate amount according to the operating state of the engine. About.

[0002]

2. Description of the Related Art As a lubricating oil supply device for a two-stroke engine, an engine-driven lubricating oil pump having a discharge amount corresponding to the engine speed has conventionally been adopted, and for example, as shown by a characteristic line a in FIG. A device is generally used in which the plunger stroke of the lubricating oil pump is changed in accordance with the engine speed and the accelerator opening, thereby controlling the discharge amount of the pump itself to an amount along the engine output curve b. . However, in this conventional device, for example, when the accelerator is widely opened and accelerated from a low-speed running state, the plunger stroke becomes unnecessarily large as shown by a characteristic line c in FIG. 4, so that excessive lubricating oil is supplied to the engine, and eventually With this conventional device, it is difficult to control the oil amount according to the operating state of the engine.

In order to solve the above problem, a return passage is conventionally connected to a lubricating oil supply passage, and when either the supply passage side or the return passage side is opened at the connection portion, the other is connected. There has been proposed a lubricating oil supply apparatus in which a three-way solenoid valve for closing is disposed and the duty of the solenoid valve is controlled (for example, see Japanese Patent Application Laid-Open No. 2-139307). In the conventional device that controls the duty of the three-way solenoid valve, the excess lubricating oil is returned to the pump suction side by controlling the duty ratio in accordance with the operation state of the engine. It is possible to supply an appropriate amount of lubricating oil to the engine.

[0004]

When the duty control is performed, how to set the control interval is an important problem. That is, for example, in the case of a lubricating oil pump of a type driven by an engine, the reciprocating time of the plunger changes according to the rotation speed of the engine. Therefore, depending on the setting of the control interval, for example, the three-way solenoid valve is connected to the supply passage side. It is possible that the timing of opening the plunger is shifted from the timing of forward movement of the plunger, and eventually the amount of oil supplied to the engine is not proportional to the duty ratio. Further, if the control interval is too long, for example, there is a concern that responsiveness in lubricating oil supply becomes insufficient at the time of sudden acceleration or the like.

Therefore, the applicant of the present application has proposed a lubricating oil supply device in which the control interval is set shorter as the engine speed is higher and longer as the engine speed is lower, or is set shorter as the accelerator opening speed is higher. (Japanese Patent Application No. 3-108651).
However, according to a subsequent experimental study, in the device according to the above proposal, a required oil supply amount and a required duty ratio are obtained from the engine speed, the throttle opening, and the like, and a control interval of the duty ratio is obtained from the engine speed and the like. Therefore, the time during which the supply passage is opened (discharge time) and the time during which the return passage is opened (pause time) are different for each required duty ratio. It has been found that the operation of the solenoid valve may be difficult to follow.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and provides a lubricant supply for a two-stroke engine capable of supplying an appropriate amount of lubricant to the engine according to the operating state of the engine while simplifying the calculation in the control device. It is intended to provide a device.

[0007]

According to the present invention, a lubricating oil pump driven by the engine is connected to a two-stroke engine via a supply passage, and the supply passage communicates with the suction side of the lubricating oil pump. A return passage is provided, and a switching valve that opens the other when one of the return passage side and the supply passage side is closed is disposed at a connection portion between the return passage and the supply passage, and the switching valve performs duty control. In the lubricating oil supply device for a two-stroke engine provided with a control device, the duty control is performed by changing the pause time for opening the return passage side while keeping the discharge time for opening the supply passage side constant. The ratio is divided into a plurality of stages, and the discharge time is set to be constant for each stage, and set shorter for lower request duty ratio stages and longer for higher request duty ratio stages. It is a symptom.

[0008]

According to the lubricating oil supply device of the present invention, the discharge time is fixed and the pause time is changed.
If the required duty ratio is obtained from the engine speed and the like, the discharge time and the pause time are immediately determined from this, and the discharge time and the like do not differ depending on the engine speed and the like, and the calculation is simple accordingly. Further, the required duty ratio is divided into a plurality of stages, and the constant value of the discharge time is set to be shorter as the duty ratio is lower and longer as the duty ratio is higher. Since the time can be reduced, it is possible to cope with a sudden change in the required duty ratio. In addition, even when the required duty ratio is high, the pause time can be secured to some extent, so that it is easy to match the required duty ratio while ensuring the followability of the switching valve.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIGS. 1 to 3 are diagrams for explaining a lubricating oil supply device for a two-stroke engine according to an embodiment of the present invention. FIG. 1 is a configuration diagram, FIG. 2 is a waveform diagram of duty control, and FIG. FIG.

In the figure, reference numeral 1 denotes a lubricating oil supply device,
In this configuration, a lubricating oil pump 3 is connected to the engine 2 via a supply passage 4, and an oil tank 5 is connected to a suction side of the lubricating oil pump 3.
Are connected via an introduction passage 6, and the supply passage 4 and the introduction passage 6 are connected by a return passage 7 which bypasses the lubricating oil pump 3.

A three-way solenoid valve 8 is provided at the connection between the return passage 7 and the supply passage 4. This solenoid valve 8
Is a valve body 9 having a supply port 9a communicating with the supply passage 4 side and a return port 9b communicating with the return path 7 side, and any one of the supply port 9a and the return port 9b arranged in the body 9. The valve body 10 which closes the other when one is opened
And an urging spring 11 for urging the valve element 10 to a position for closing the supply port 9a, and an electromagnetic coil 12 for moving the valve element 10 to a position for opening the supply port 9a when energized.

Reference numeral 13 denotes the electromagnetic coil 12 of the three-way solenoid valve 8.
CPUs for controlling the power supply to the power supply, and 14 and 15 are main switches and batteries. The CPU 13 receives signals representing the engine speed, the accelerator opening, and other engine operating conditions, calculates the amount of lubricating oil required by the engine based on these signals, and calculates the amount of lubricating oil to the engine. The duty ratio is determined so as to be the required amount, and the energization of the electromagnetic coil 12 of the three-way solenoid valve 8 is duty-controlled. In this case, as shown in FIG. 2, the required duty ratio is divided into three stages of A, B, and C, and the discharge time during which the supply port 9a is opened at each stage is set to a constant value of a, b, and c. And the rest periods a ′, b ′,
The required duty ratio is realized by changing c '. Here, it is desirable that the discharge time a at the stage where the required duty ratio is small (for example, A) is set substantially equal to the stroke interval of the pump at the time of the minimum engine speed. In setting the maximum required duty ratio (excluding the case of 100%), it is set so that the maximum required duty ratio = discharge time / (discharge time + switching valve follow-up time) × 100%. The maximum required duty ratio is the maximum value of the duty ratio existing in the actual mode. When the duty ratio is 100%, the solenoid valve 8 is continuously opened.

Next, the operation and effect of this embodiment will be described with reference to the flowchart of FIG. The CPU 13 reads the engine speed, the throttle opening, etc., calculates a map of the required amount of lubricating oil, and calculates the required duty ratio D for realizing the amount of lubricating oil, the engine speed, the pump stroke number, and the pump discharge capacity. (Steps S1 and S2).
Then, it is determined at which stage the required duty ratio D is. In this case, the required duty ratio D is 20
If it is not more than%, it is determined that the required duty ratio is in the stage A, the discharge time is determined as a, and the pause time a 'is obtained from the required duty ratio D and the discharge time a (steps S3 to S5). The discharge time a, the pause time a '
Is output to the switching valve 8 (step S6). Thus, for example, when the required duty ratio D is 20%, the switching valve 8 is set to the supply port 9a
Is opened, and then the return port 9b is opened for 4a seconds.

If the required duty ratio D is larger than 20% and equal to or less than 60%, the required duty ratio is determined to be in the stage B, the discharge time is determined as b, and the pause time b 'is determined. Duty control is performed accordingly (steps S7 to S9, S6), and the required duty ratio is set to 60
If it is greater than%, it is determined that the process is in the above-mentioned stage C, the discharge time is determined to be c, the pause time c 'is obtained, and the duty control is performed (steps S10, S11, S6).

As described above, in this embodiment, the discharge time is set to a,
Since the duty control is performed by determining the constant value of either b or c and changing the pause time,
If the required duty ratio is determined according to the engine speed,
The discharge time and the pause time can be immediately determined, and the calculation in the control device is simpler than when the control interval is changed according to the engine speed. By this duty control, it is possible to secure an oil supply amount according to the operation state of the engine. As a result, it is possible to make the amount of lubricating oil to the engine correspond to the output characteristic curve b in FIG. Excessive supply can be avoided, and problems such as exhaust smoke and oil scattering can be solved.

When the required duty ratio is small, the discharge time is set to a constant value on the shorter side, so that the pause time can be set relatively short while the duty ratio is reduced, and therefore the time required for control can be shortened accordingly. Responsiveness to a change in duty ratio can be improved. When the required duty ratio is large, the discharge time is set to a constant value on the long side, so that the pause time can be set relatively long while increasing the duty ratio, and the required duty ratio can be set while maintaining the response time of the switching valve 8. Can be easily adapted.

As described above, according to the lubricating oil supply device for a two-stroke engine according to the present invention, the discharge time is made constant, and the duty control is performed by changing the idle time. There is an effect that can be converted. In setting the discharge time, when the required duty ratio is small, it is kept constant on the short side, and when it is large, it is kept constant on the long side. There is an effect that the duty ratio can be adjusted.

[Brief description of the drawings]

FIG. 1 is a block diagram of a lubricating oil supply device for a two-stroke engine according to one embodiment of the present invention.

FIG. 2 is a waveform chart for explaining a control method of the apparatus of the embodiment.

FIG. 3 is a flowchart for explaining a control method of the apparatus of the embodiment.

FIG. 4 is a diagram for explaining problems of the conventional device and effects of the present embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lubricating oil supply device 2 engine 3 lubricating oil pump 4 supply passage 7 return passage 8 three-way solenoid valve (switching valve) 13 CPU (switching control device)

Claims (1)

(57) [Claims] 1. A two-stroke engine, wherein a lubricating oil pump driven by the engine is connected via a supply passage, and a return passage communicating between the supply passage and a suction side of the lubricating oil pump is provided. A two-stroke engine provided with a switching valve at a connection portion between the valve and the supply passage and a switching valve that opens the other when one of the return passage side and the supply passage side is closed, and a duty control of the switching valve is provided. In the lubricating oil supply device of the present invention, the duty control is performed by making the discharge time for opening the supply passage side constant and changing the pause time for opening the return passage side, and changing the required duty ratio.
Is divided into a plurality of stages, and the above-mentioned ejection time is fixed at each stage.
And the lower the required duty ratio, the shorter the required duty ratio.
A lubricating oil supply device for a two-stroke engine, wherein the longer the duty ratio, the longer the setting .