JP2758971B2 - Electronic control mechanism of gasoline engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Field of the Invention The present invention relates to a general-purpose gasoline engine, which detects a state at the time of starting or operation by a sensor provided in each part and automatically adjusts a governor and a choke. It relates to an electronic control mechanism.

(B) Conventional technology As a technology relating to an electronic control device of an engine using a temperature sensor, a technology described in Japanese Patent Publication No. 63-60223 is known.

(C) Problems to be Solved by the Invention In a conventional general-purpose gasoline engine, since the choke is operated by the suction negative pressure of the intake and automatically controlled, when the difference between the suction temperature and the cylinder head temperature is severe, , Choke shortage, or engine choke due to auto choke often occur.
It was necessary to add bimetal and the like.

As a result, the cost and the complexity of the apparatus have become problems.

Conventionally, in an electronic control unit, an automatic choke, a slowdown control, an oil alert control,
Since the electronic governor over-rotation prevention mechanism was configured to operate independently and with separate components, the number of parts was large,
This was a cause of increased costs, and it was difficult to secure a space for mounting.

Conventionally, as shown in FIG. 3, a temperature sensor 20 'is attached to the head cover 23 of the cylinder head 1 to operate and sense the bimetal at the ambient temperature of the entire engine to determine the opening degree of the choke. If the cylinder head temperature is high immediately after the engine is stopped and the suction temperature is low, the automatic choke will be in an over-choke state, and there will be a problem that the starting will be poor due to the change mechanism.

Therefore, conventionally, a choke that opens and closes by suction negative pressure has been used as a main control device, and control by a temperature sensor has been used as an auxiliary device.

The present invention has solved the problems of the control mechanism of the gasoline engine described above.

(D) Means for Solving the Problems The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

In claim (1), detection signals from a temperature sensor mounted near the cylinder head and a sensor for detecting the number of revolutions of the engine are determined, and at the time of low temperature starting, the choke opening / closing actuator is “fully closed” → It operates in three stages of "half open" → "fully open", and in the "half open" stage, the choke opening / closing actuator is maintained in the "half open" state for a certain period of time when a predetermined number of revolutions is exceeded. When the engine is started at a high temperature, the choke opening / closing actuator is controlled in two stages from “fully closed” to “fully opened”.

According to a second aspect of the present invention, in the engine control mechanism according to the first aspect, an automatic choke mechanism that operates a choke actuator in response to a signal from a temperature sensor to automatically open and close the choke and an engine rotation when the load decreases. A slowdown mechanism that reduces the engine to idling speed, an oil alert mechanism that turns on the oil alert lamp when the oil level is below the specified amount, and an electronic governor overspeed that stops the engine when the engine speed becomes overspeed The operation of the prevention mechanism is controlled by a set of electronic controllers.

(E) Embodiment The problems to be solved and means to be solved by the present invention are as described above. Next, the configuration of the embodiment shown in the accompanying drawings will be described.

FIG. 1 is an overall front view of an engine showing an embodiment of the present invention,
2 is a plan view, FIG. 3 is a rear view, FIG. 4 is an operation flowchart of the electronic controller C, FIG. 5 is a block diagram of the electronic controller C, and FIG. 6 is an operation flowchart of the auto choke mechanism. FIG. 7 is a drawing showing the operation of the auto choke mechanism at a low temperature, and FIG. 8 is a drawing showing the operation of the auto choke mechanism at a high temperature.

The engine shown in FIGS. 1, 2 and 3 is an inclined cylinder type engine in which the cylinder center line is inclined in an oblique direction, and the cylinder head 1 is obliquely above the crankshaft center P in FIG. Projecting to

On one side of the engine block in the crankshaft direction,
A fan case 2 for a cooling fan driven by a crankshaft is mounted. A carburetor 3 is mounted on the same side of the cylinder head 1 as the fan case 2. An air cleaner 5 is mounted on the inlet side of the carburetor 3.

A throttle actuator 7 is fixed to the side of the fan case 2 on the upper side of the central circular protrusion 6 by bolts 8,8.

A throttle shaft 11 protruding above the carburetor 3 and levers 9 and 12 of an output shaft 10 of the actuator 7 are connected to each other by a link 14 having a coil spring 13 in the middle.

On the upper side of the cylinder head 1, the fan case 2
An air guide plate 15 for flowing the cooling air sucked by the cooling fan along the cylinder head 1 is fixed by bolts 16.

A mounting plate 18 for a choke actuator 17 is provided between the mounting surface of the vaporizer 3 and the mounting surface of the actuator 7, and a piston 17 a of the choke actuator 17 mounted and fixed on the mounting plate 18. Is connected to a choke lever 19 to operate the choke to “fully close”, “half open”, and “fully open” by operating the choke actuator 17.

The choke mechanism has a choke valve disposed inside the carburetor 3. By closing the choke valve in cold weather, the amount of intake air is reduced, and the internal negative pressure is increased. Since a large negative pressure is generated in the part on the combustion chamber side, a large amount of fuel is sucked from the fuel pipe introduced to the carburetor 3, and a rich mixture is ejected from the main nozzle to the venturi. is there.

This facilitates starting even in cold weather.

The throttle actuator 7 is constituted by a solenoid in a pulling direction, and is provided with a return spring 17b.

Further, in the present invention, a temperature sensor 20 for measuring the temperature of the cylinder head 1 as a signal for adjusting the degree of opening and closing of the choke is attached to the head of the cylinder head 1.

An oil sensor 27 is provided inside the cylinder block B.
And an engine rotation sensor 30 that detects the number of rotations of the crankshaft 33 is provided.

A starting motor 24 is provided at the right shoulder of the fan case 2, and a starting handle 26 and a starting rope mechanism 25 are provided on the front side of the fan case 2.
28 is an exhaust muffler.

As shown in FIG. 5, in the engine of the present invention, an engine rotation sensor 30, an engine temperature sensor 20, and an oil sensor 27 are arranged as sensors.

Further, as operation switches, a 50/60 Hz changeover switch 35, a load current detection switch 36, and a slow down switch 37 are arranged.

The load current detection switch 36 detects the load on the engine by detecting the current, and the slow down switch 37 is a switch that performs control to reduce the engine rotation to idling rotation when the load decreases. is there.

Based on the signals from these switches and the sensors, comparison and determination are performed in the microcomputer portion inside the controller C, and instruction signals are output to the throttle actuator 7, igniter 41, and choke actuator 17 as operating portions. It is done.

The rotation speed signal detected by the engine rotation sensor 30 is transmitted to an engine stall detector 42, a 1000 rotation or less determination unit, a low speed rotation control unit 43, and an overrun detector 32.

Then, when the engine speed is 1000 rpm or less, the degree of opening and closing of the auto choke changes, and the choke valve is “fully closed”.
A determination of "half open" or "full open" is made.

The low-speed rotation control unit 43 controls the constant-speed rotation. When the rotation speed is overrun by the electronic governor overspeed prevention mechanism, the engine is stopped by the igniter 41.

When the rotation speed of the engine increases or decreases, the throttle shaft 11 is rotated by operating the throttle actuator 7 in a decreasing direction so as to maintain a constant speed.

When the slow-down switch 37 is pressed, and when a no-load state is detected based on a signal from the load current detection switch 36, control to reduce the rotation to idling is performed by the rotation speed support unit 39.

Further, it is determined whether the temperature is low or high based on the temperature of the cylinder head portion detected by the temperature sensor 20, and the choke valve is switched between "fully closed", "half open" and "fully open".

In the case of “fully closed”, the 8-second timer 44 is activated, and becomes “fully opened” after the lapse of 8 seconds.
The second timer 45 is activated, and becomes "full open" after 15 seconds have elapsed.

(F) Operation of the Invention The operation of the present invention will be described with reference to the control flowchart of FIG.

First, it is determined whether or not the oil level is a specified amount. If the oil level is equal to or less than the determined amount, the oil sensor 27 is turned on, and the oil alert lamp is turned on for 3 to 5 seconds. Thereafter, the primary line of the igniter 41 is short-circuited, the spark ignition is stopped, and the engine is stopped.

If the oil level is normal, the temperature sensor
The temperature in the vicinity of the cylinder head 1 is detected by 20. If the temperature is 15 ° C or higher, the auto choke is set to “fully closed”.
Then, it is set to "full open" immediately after about one second has elapsed.

When the temperature of the temperature sensor 20 is 15 ° C. or lower, the auto choke is set to “fully closed”, and the “fully closed” state is maintained until the number of rotations increases to 1000 or more.

Then, when the rotation speed becomes 1000 rotations or more, the auto choke is set to “half open”. The holding time of “half open” is about 15 seconds, and then the auto choke is “full open”.

As a result, the operation is performed with the no-load maximum rotational speed.

 The above is the control action of the auto choke.

Next, when the load current detection switch 36 is turned on, the state of the maximum no-load speed of 1000 seconds has passed, and when the load detection current is 40 A or more, the rated speed is 3000 to 3600 rpm. The control is performed so that

Then, when the load becomes a no-load state, if the slowdown switch 31 is turned on, a slowdown control for reducing the rotation to the idling rotation is performed.

Further, since the electronic governor over-rotation prevention mechanism is provided, when the engine speed exceeds 4500 rpm, the primary line of the oil sensor 27 is short-circuited and the engine is stopped.

When the load current detection switch 36 is OFF, the rotation speed is controlled to 2100 rotations.

Also, when the engine is stopped, the engine speed is reduced along with the primary line short-circuit when the engine is stopped. Refuse and shut off the engine.

FIG. 6 discloses a flowchart of only the automatic choke mechanism, and FIGS. 7 and 8 show the open / closed state of the choke valve at low and high temperatures.

As shown in FIG. 7, in the case of a low temperature of 15 ° C. or less, first, it is set to “fully closed”, and it is determined whether the rotation speed is 1000 rotations or more.
The choke actuator 17 performs control to switch to “fully open” when 15 seconds have elapsed in the “half open” state after “00 half rotation” or “half open”.

In the case of a high temperature of 15 ° C. or more as shown in FIG. 8, first, the auto choke is set to “fully closed”, and after 1 second, “full open” is determined. "Fully closed" and "fully open" are repeated.

The automatic choke control at the time of high temperature in FIG. 4 and the control in FIGS. 6 and 8 are slightly different in that “full open” and “fully close” are repeated.

(G) Effects of the Invention The present invention is configured as described above, and has the following effects.

As described in claim (1), the choke opening / closing actuator is operated in three stages of “fully closed” → “half open” → “fully open” at the time of a low temperature start, and “fully closed” → at the time of a high temperature start. The release mechanism that controls in two stages of "full open" is provided, which is a drawback of the conventional gasoline engine. The choke is operated by the suction negative pressure of the intake and automatically controlled. When there was a large difference between the two, the lack of choke or auto choke caused an engine start failure, which improved the need for manual assistance or the addition of bimetal, etc. .

In addition, such a control mechanism can be configured as an auto actuator which is simple, inexpensive, and has a reliable starting performance.

In the engine control mechanism, the automatic choke, the slowdown, the oil alert, and the electronic governor overspeed prevention mechanism are configured to be controlled by a set of electronic controllers. Choke, slowdown control, oil alert control, and electronic governor overspeed prevention mechanism have been improved so that they were configured to operate independently and with separate parts, reducing the number of parts and increasing costs. In addition, each device of the control mechanism, for which it was difficult to secure a space for mounting, could be simply combined into a simple configuration.

[Brief description of the drawings]

1 is an overall front view of an engine showing an embodiment of the present invention, FIG. 2 is a plan view of the same, FIG. 3 is a rear view of the same, FIG. 4 is an operation flowchart of an electronic controller C, and FIG. C is a block diagram, FIG. 6 is an operation flowchart of the auto choke mechanism, FIG. 7 is a drawing showing the operation of the auto choke mechanism when the temperature is low, and FIG. 8 is a drawing showing the operation of the auto choke mechanism when the temperature is high. It is. 1 Cylinder head 7 Throttle actuator 9 Lever 11 Throttle shaft 19 Choke lever 17 Choke actuator 20 Temperature sensor 27 Oil sensor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02M 1/10 F02D 45/00 310

Claims (2)

(57) [Claims] The system detects a detection signal from a temperature sensor mounted near the cylinder head and a sensor for detecting the number of revolutions of the engine. When starting at a low temperature, the choke opening / closing actuator is changed from "fully closed" to "half open". → "Fully open" 3
In the "half open" stage, the choke opening / closing actuator is configured to be maintained in the "half open" state for a predetermined period of time when the rotation speed exceeds a predetermined number of revolutions. An electronic control mechanism for a gasoline engine, wherein an opening / closing actuator is controlled in two stages from "fully closed" to "fully opened". 2. An engine control mechanism according to claim 1, wherein a choke actuator is actuated by a signal from a temperature sensor to automatically open and close the choke, and an idling rotation of the engine when the load is reduced. A slowdown mechanism that reduces the engine speed, an oil alert mechanism that turns on the oil alert lamp when the oil level is below the specified amount, and an electronic governor overspeed prevention mechanism that stops the engine when the engine speed becomes excessive. An electronic control mechanism for a gasoline engine, wherein the operation is controlled by a set of electronic controllers.