JP3091927B2 - Lubrication control 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 lubrication control device for a two-stroke engine.

[0002]

2. Description of the Related Art As a lubrication system for a two-cycle engine,
In some cases, oil is supplied separately from fuel. Japanese Unexamined Patent Publication No. 2-191807 discloses that in such a separate oil supply system, an electromagnetic three-way valve controlled by a microcomputer is connected to the discharge side of an oil pump to return the oil to the oil tank together with the supply path to the engine. Form a path,
There is disclosed an engine in which excess oil is returned to an oil tank in accordance with an engine load to perform optimal engine lubrication. Further, the electromagnetic three-way valve is configured to be normally opened to the engine supply path side when no power is supplied, so that even if a failure occurs in the electric system, the engine can be reliably lubricated.

However, in such a lubrication control device, if the microcomputer control unit that drives the electromagnetic three-way valve operates abnormally due to a failure, it is not always possible to supply oil to the engine. There was a problem that the merit could not be used.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a two-stroke engine lubrication control device which can reliably lubricate an engine even when an abnormality occurs in the microcomputer control unit as described above. It is in.

[0005]

In order to achieve the above object, the present invention provides an electromagnetic three-way valve on the discharge side of an oil pump, and a supply path to the engine and a return path to the oil tank via the electromagnetic three-way valve. The electromagnetic three-way valve is configured such that the oil passage is normally opened to the engine supply path side when the power is not supplied to the electromagnetic three-way valve. Control device, a plurality of output ports are provided in the microcomputer control unit, and the drive circuit of the electromagnetic three-way valve comprising a logic circuit having these as input terminals is connected to the plurality of output ports. The logic circuit is configured to output a drive signal only when the outputs of the plurality of output ports have a specific pattern.

[0006] The form in which the microcomputer control unit becomes abnormal is as follows: (a) When the microcomputer cannot operate at all when the clock is stopped,
It is conceivable that (b) the program runs away, or (c) there is a partial hardware failure. Of these abnormalities, the case (b) can be prevented by a commonly used watchdog circuit. In the case of (a), since the microcomputer control unit is in the reset state, the drive circuit does not output, and in the case of (c),
The drive circuit does not output because the specific pattern does not output to the output port.

In other words, according to the lubrication control device of the present invention, when an abnormality occurs in the microcomputer control unit, the output of the plurality of output ports becomes other than a specific pattern, so that no drive signal is output from the drive circuit. Then, the electromagnetic three-way valve is normally opened on the engine supply path side. Therefore, the oil discharged from the oil pump is continuously supplied to the engine side, and the engine is lubricated.

[0008]

FIG. 1 is a system diagram showing a lubrication control device for a two-cycle engine according to an embodiment of the present invention. In the figure, 1 is a two-stroke engine, and 2 is a plunger type oil pump. The oil pump 2 is driven by the power of the crankshaft of the engine 1 and has a throttle opening V
Thus, the stroke amount is controlled to change the discharge amount. An electromagnetic three-way valve 3 is connected to the discharge side of the oil pump 2, and a supply path A to the engine 1 and a return path B to the oil tank 4 via the electromagnetic three-way valve 3.
Are formed.

The electromagnetic three-way valve 3 is normally open on the engine supply path A side when no power is supplied or when no drive signal is output from the control unit 5, and has a valve structure for supplying oil only to the engine 1. ing. In addition, the electromagnetic three-way valve 3
Is driven by the control unit 5 according to the engine load when the power is supplied, and returns an excess amount of oil discharged from the oil pump 2 to the oil tank 4. The control unit 5 determines the split ratio to the recirculation path B based on the duty ratio determined from the throttle opening V and the engine speed N, and sets the minimum oil amount for the engine 1 that does not generate white smoke in the exhaust gas. Is supplied.

As shown in FIG. 2, the control unit 5 is provided with a power supply circuit 9 via a main switch 8 and
It has a microcomputer control unit 6. The microcomputer control unit 6 receives the throttle opening V and the engine speed N, and has two output ports on the output side. A drive circuit 7 composed of a logic circuit having these as input terminals is connected to the two output ports, and the electromagnetic three-way valve 3 is driven by a drive signal output from the drive circuit 7. The drive circuit 7 activates the electromagnetic three-way valve 3 only when the output port of the microcomputer control unit 6 has a specific pattern, that is, when the output port is in the H (Hi) state and the output port is in the L (Low) state. It is composed of a logic circuit that outputs a driving signal.

For example, if the microcomputer control section 6 remains in a reset state due to a failure of an oscillation circuit or the like in the microcomputer control section 6, the output terminal of the microcomputer control section 6 is connected to a pull-up resistor (not shown). ) To output port,
Are set to the H state. Since it is not the specific pattern described above, the output of the drive circuit 7 (logic circuit) becomes L, and no drive signal is output. Also, even when each of the output ports does not operate, such as when the microcomputer control unit 6 is in a reset state, no drive signal is output.

If the drive signal is not output from the drive circuit 7 as described above, the electromagnetic three-way valve 3 is not driven, so that it is normally opened on the engine supply path A side, and the oil is continuously supplied to the engine 1. Therefore, even if an abnormality occurs in the microcomputer control unit, reliable engine lubrication becomes possible. FIG. 3 shows an actual application example of the above-described lubrication control device. One port of an open drain terminal (not shown) with a pull-up resistor of the microcomputer control unit 6 is connected to the base of the transistor 10 and the other is connected. The port is connected to a collector, which is connected to an FET (field effect transistor) 11. Also,
FIG. 4 shows the configuration together with the microcomputer control unit for the ignition circuit. Since the input signals (throttle opening V and engine speed N) are made common, the control system can be simplified by combining them as in this example.

[0013]

As described above, according to the present invention, an electromagnetic three-way valve is provided on the discharge side of the oil pump, and a supply path to the engine and a return path to the oil tank are formed through the electromagnetic three-way valve. When the three-way valve is not energized, the oil passage is normally opened to the engine supply path side, and when energized, control is performed via the microcomputer control unit to return excess oil to the oil tank according to the engine load. In the lubrication control device for a cycle engine, the microcomputer control unit is provided with a plurality of output ports, and the plurality of output ports is connected to a drive circuit of the electromagnetic three-way valve including a logic circuit having these as input terminals. Is configured to output a drive signal only when the outputs of the plurality of output ports are in a specific pattern. Three-way solenoid valve driving signal of the circuit is not output is no longer driven. Therefore, the oil is continuously supplied only to the engine, thereby enabling reliable engine lubrication.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a lubrication control device for a two-cycle engine according to an embodiment of the present invention.

FIG. 2 is a system diagram showing a control unit portion of the lubrication control device.

FIG. 3 is a system diagram showing a specific example of a control unit according to the present invention.

FIG. 4 is a system diagram showing another specific example of the control unit of the present invention.

[Explanation of symbols]

Reference Signs List 1 2 cycle engine 2 oil pump 3 solenoid three-way valve 4 oil tank 5 control unit 6 microcomputer control unit 7 drive circuit (logic circuit)

Claims (1)

(57) [Claims] 1. An electromagnetic three-way valve is provided on the discharge side of an oil pump, and a supply path to an engine and a return path to an oil tank are formed through the electromagnetic three-way valve. A two-stroke engine lubrication control device configured to be normally open to the engine supply path side and to control excess oil to return to the oil tank according to the engine load via a microcomputer control unit when energized, A plurality of output ports are provided in the microcomputer control unit, and a drive circuit for the electromagnetic three-way valve including a logic circuit having these input ports is connected to the plurality of output ports, and the logic circuit outputs the output signals of the plurality of output ports. Is a lubrication control device for a two-stroke engine in which a drive signal is output only when the pattern is a specific pattern.