JPH0828230A - Lubrication device of 2-cycle engine - Google Patents

Abstract

PURPOSE:To precisely control oil supply quantity across the whole rotational speed range and at the same time continuously supply oil in medium to high rotational speed range so as to improve durability of an engine. CONSTITUTION:A lubrication device is provided with an oil tank 8, an oil path 9, an oil pump 11 connected on the way to this oil path 9, a valve means (a switch valve 21) connected to the oil path 9 on the downstream side of the oil pump 11 and opening the valve at a prescribed cycle so as to communicate the oil path 9 thereto, an engine rotational speed sensor 13, and a control means 14 for operating the valve means (the switch valve 12) based on the input from the engine rotational speed sensor 13. The control means 14 controls at least one of such controls that shorten valve opening cycle of the valve means (the switch valve 12) as the engine rotation speed increases, and shorten the valve opening cycle of the valve means (the switch valve 12) as the engine rotational speed increases and at the same time elongates the valve opening time of the valve means (the switch valve 12).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating system for a two-cycle engine.

[0002]

2. Description of the Related Art FIG. 1 is a block diagram showing an example of a lubrication device for a two-cycle engine. The 2-cycle engine 1
A cylinder assembly 3 is provided on the crankcase 2, an intake pipe 4 is provided on the crankcase 2, and a carburetor 5 is connected to the intake pipe 4. An exhaust pipe 6 is connected to the cylinder assembly 3.

The lubricating device 7 includes an oil tank 8 installed outside the two-cycle engine 1, an oil passage 9, an oil pump 11, a switching valve 12, and an engine speed sensor 13.
And a control means 14.

The oil passage 9 is connected to the oil tank 8.
It is connected to the lubrication part of the cycle engine 1, for example, the intake pipe 4. The oil pump 11 is connected in the middle of the oil passage 9 and is driven when the two-cycle engine 1 is operated to supply the oil in the oil tank 8 to the intake pipe 4. The oil supplied to the intake pipe 4 is mixed with the air-fuel mixture from the carburetor 5 and enters the crankcase 2 to lubricate the inside of the engine.

The amount of oil discharged from the oil pump 11 increases in proportion to the increase in engine speed. The oil pump 11 is, for example, a plunger pump that intermittently discharges an accurate amount of oil.

On the other hand, the switching valve 12 is connected to the oil passage 9 on the downstream side of the oil pump 11, and serves as a valve means for opening (closing) the oil passage 9 at a predetermined cycle to communicate the oil passage 9. Is. The engine speed sensor 13 is a sensor that detects the speed of the two-cycle engine and inputs it to the control means 14.

A relief passage 15 extends from the switching valve 12 and is connected to the oil passage 9 on the upstream side of the oil pump 11. In the middle of the relief passage 15, the relief valve 15 extends from the switching valve 12 to the oil passage 9 side. Relief valve 16 that allows only flow
Is connected.

The control means 14 is a CPU or the like that operates the switching valve 12 based on the input from the engine speed sensor 13,
As shown in FIG. 4, the engine speed is 0 to N1, N1 to N2,
N2 to N3, N3 to N4, N4 to N5, and N5 and above (0 <N1 <N2 <
N3 <N4 <N5), for example, the switching valve 12 is divided into 6 stages, and the switching valve 12 is always opened at a constant valve opening period T.
The valve opening time at that time is t as the engine speed increases.
Control so that the time becomes 1, t2, and so on.

That is, in the engine speed range of 0 to N1, the valve opening time is set to the shortest time t1, and the valve opening rate (valve opening time) of the switching valve 12 during the valve opening cycle T is, for example, 6 minutes. Set to 1. Further, when the engine speed is in the range of N1 to N2, the valve opening time becomes t2 and the valve opening rate of the switching valve 12 is, for example, 6
It is set to 2/2. Below, engine speed range N2 to N3
Valve opening time t3 (valve opening rate 3/6), N3 to N4 valve opening time t4 (valve opening rate 6/4), N4 to N5 valve opening time t5 (valve opening rate 5/6) Then, when N5 or more, the valve opening time becomes t6 which is the same as the valve opening period T (valve opening ratio 6/6), and the switching valve 12 is kept in the fully open state.

When the switching valve 12 is closed, the oil discharged from the oil pump 11 is returned to the upstream side of the oil pump 11 via the relief passage 15 and the relief valve 16. Therefore, an increase in the internal pressure of the oil pump 11 and the oil passage 9 on the downstream side of the oil pump 11 is avoided, and oil leakage is prevented.

As described above, if the valve opening ratio of the switching valve 12 is controlled to increase as the engine speed increases, it is possible to supply an appropriate amount of oil commensurate with all engine speeds. It is possible to prevent seizure and generation of white smoke in exhaust gas due to excess oil.

[0012]

However, in the case of such a lubricating device 7, the valve opening period T of the switching valve 12 is always set to be constant irrespective of the engine speed, so that the oil supply amount can be accurately adjusted. I couldn't control it.

For example, when the engine speed fluctuates drastically, the switching valve 12 is closed and the engine speed rises sharply when the oil supply is stopped, or the switching valve
The engine speed may drop sharply when 12 is opened and oil is being supplied. In such a case, until the next valve opening cycle T comes and the opening time of the switching valve 12 is reset. Since this state is maintained, there is a risk that the oil supply will not be in time or that the oil will be excessively supplied.

Further, since the absolute value of the closing time of the switching valve 12, that is, the absolute value of the time during which the oil is being relieved is large, the oil supply is intermittent even in the medium to high speed rotation range, and the durability of the engine is improved. May decrease.

The present invention has been made in order to solve such a problem, and controls the oil supply amount with high accuracy in the entire rotational speed range and continuously supplies the oil in the medium to high speed rotational range. An object of the present invention is to provide a lubrication device for a two-cycle engine that can improve the durability of the engine.

[0016]

In order to achieve the above object, a lubrication device for a two-cycle engine according to the present invention includes an oil tank, an oil passage connecting the oil tank to a lubrication portion of the two-cycle engine, and the oil. An oil pump connected in the middle of the passage to supply the oil in the oil tank to the two-cycle engine side, and a valve connected to the oil passage on the downstream side of the oil pump and opened at a predetermined cycle to communicate the oil passage. Means, an engine speed sensor for detecting the speed of the two-cycle engine, and a control means for actuating the valve means based on an input from the engine speed sensor. It is the same as the control that shortens the valve opening cycle of the valve means as the engine speed increases and shortens the valve opening cycle of the valve means as the engine speed increases. It is characterized in that performing at least one control of the control to increase the opening time of the valve means.

[0017]

When the lubrication system for a two-cycle engine is constructed in this way, even if the engine speed fluctuates drastically, the valve opening period of the valve means becomes smaller as the engine speed increases. The time until the next valve opening period comes and the valve opening time of the switching valve is reset is shortened, shortage or excessive supply of oil is prevented, and accurate oil supply is performed. Further, the oil can be continuously supplied in the medium to high speed rotation range, and the durability of the engine can be improved.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. 2 and 3 are timing charts showing an example of control of the switching valve 12 by the control means 14 of the lubricating device 7 shown in FIG. 1, respectively.

In the control example (1) shown in FIG. 2, the opening cycle of the switching valve 12, which is the valve means, is shortened as the engine speed of the two-cycle engine 1 increases. Control means 14
Is the engine speed 0 to N1, N1 to N2, N2 to N3, N3 to N
4, N4 to N5, and N5 or more (0 <N1 <N2 <N3 <N4 <N5)
In this way, for example, it is divided into six stages, and the valve opening cycle of the switching valve 12 corresponding to each engine revolution speed stage is set based on the input from the engine revolution speed sensor 13. here,
The valve opening time t of the switching valve 12 is always kept constant.

The opening cycle of the switching valve 12 is such that the engine speed is 0.
It is set to the longest T1 in the range of to N1, and this valve opening period T1
The valve opening rate (valve opening time) of the switching valve 12 in the inside is, for example, 6
It is set to one-half. Further, in the engine speed range of N1 to N2, the valve opening period is set to T2, which is shorter than T1, and the valve opening rate of the switching valve 12 is, for example, 2/6. Hereinafter, in the engine speed range N2 to N3, the valve opening period T3 (valve opening rate 3/6),
In N3 to N4, the valve opening period T4 (valve opening rate is 4/6) is shortened, and in N4 to N5, the valve opening period is T5 (valve opening rate is 5/6). Is zero, that is, the switching valve
12 is kept fully open. The number of stages in the engine speed range and the valve opening rate in each valve opening cycle may be set to other values.

The control example (2) shown in FIG. 2 shortens the valve opening period of the switching valve 12 as the engine speed increases, and at the same time lengthens the opening time of the switching valve 12. The engine speed range is divided into, for example, 6 stages as in the case of the control example (1), and the opening cycle of the switching valve 12 is in the range of engine speed 0 to N1 as in the control example (1). Then T1,
In the range of N1 to N2, T2 in the range of N2 to N3, T3 in the range of N3 to N4, T5 in the range of N4 to N5, and T5 in the range of N5 or more. Be drunk

The opening time of the switching valve 12 is the opening cycle.
It is set to the shortest t1 at the time of T1.
2, t3 at valve opening cycle T3, t5 at valve opening cycle T4, t5 at valve opening cycle T5
And has been gradually lengthened. The valve opening rate in each of the valve opening cycles T1 to T5 is set to, for example, 1/6 as in the control example (1).

The control means 14 is a control example (1) and a control example.
At least one of (2) or both control examples (1) and (2) are mixed. Control example (1), (2) that is a mixture of both means, for example, when the engine speed is 0 to N3, the valve opening time of the switching valve 12 is fixed as in the control example (1), and the engine speed is fixed. The control mode is such that the valve opening time of the switching valve 12 is gradually increased as shown in the control example (2) from when N becomes equal to or more than N4.

When such control is performed, for example, even if the engine speed of the two-cycle engine 1 fluctuates drastically and the engine speed sharply rises when the switching valve 12 is closed, the engine speed rises. Accordingly, the valve opening period is shortened, so the valve opening time of the switching valve 12 is quickly reset,
An amount of oil suitable for high speed rotation is supplied.

Further, even when the engine speed drops sharply when the switching valve 12 is opened, the valve opening cycle becomes longer as the engine speed drops, so that an amount of oil suitable for low speed rotation is supplied. . Therefore, the oil supply amount can be accurately controlled in the entire rotation speed range.

Moreover, since the absolute value of the valve closing time of the switching valve 12, that is, the absolute value of the time during which the oil is being relieved is small, the oil supply in the medium to high speed rotation region is continuous, and the two-cycle engine 1 is operated. The durability can be improved.

The present invention can be applied not only to a two-cycle engine, but also to a dry sump type lubricating device used in a four-cycle engine, for example.

[0028]

As described above, the lubricating device for a two-cycle engine according to the present invention is connected to an oil tank, an oil passage connecting the oil tank to the lubrication portion of the two-cycle engine, and an intermediate part of the oil passage. And an oil pump for supplying the oil of the oil tank to the engine side for two cycles, a valve means connected to the oil passage on the downstream side of the oil pump and opening the valve for a predetermined period to communicate the oil passages, and two cycles An engine speed sensor for detecting an engine speed, and a control means for operating the valve means based on an input from the engine speed sensor are configured, and the control means increases with an increase in the engine speed. Control for shortening the valve opening cycle of the valve means and shortening the valve opening cycle of the valve means as the engine speed increases It is obtained to perform at least one control of the control to increase the.

Therefore, it is possible to control the oil supply amount with high accuracy in the entire rotational speed range, and to improve the durability of the engine by continuously supplying the oil in the medium to high speed rotational range.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a lubrication device for a two-cycle engine.

FIG. 2 is a timing chart showing an embodiment of the present invention and showing a control example in which the valve opening period of the valve means is shortened as the engine speed increases.

FIG. 3 is a timing chart showing an embodiment of the present invention and showing a control example in which the valve opening period of the valve means is shortened and the valve opening time of the valve means is lengthened as the engine speed increases.

FIG. 4 is a timing chart of a valve means control example showing a conventional technique.

[Explanation of symbols]

 1 2 Cycle Engine 2 Crankcase 3 Cylinder Assembly 4 Intake Pipe 5 Carburetor 6 Exhaust Pipe 7 Lubricator 8 Oil Tank 9 Oil Passage 11 Oil Pump 12 Switching Valve as Valve Means 13 Engine Speed Sensor 14 Control Means 15 Relief Passage 16 Relief Valves T1 to T5 Opening cycle of valve means t, t1 to t5 Opening time of valve means

Claims (1)

[Claims] 1. An oil tank and this oil tank
The oil passage that connects to the lubrication part of the cycle engine and the oil in the oil tank that is connected in the middle of the oil passage
An oil pump for supplying to the cycle engine side, a valve means connected to the oil passage on the downstream side of the oil pump and opening at a predetermined cycle to communicate the oil passage, and an engine for detecting the rotation speed of the two-cycle engine. The engine includes a rotation speed sensor and control means for operating the valve means based on an input from the engine rotation speed sensor, and the control means shortens the valve opening cycle of the valve means as the engine rotation speed increases. Lubrication device for a two-cycle engine, characterized in that at least one of a control for increasing the engine speed and a control for shortening the valve opening period of the valve means as well as increasing the valve opening time of the valve means is performed. .