JP4310762B2 - Engine ignition timing control structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine in which ignition timing control is mechanically interlocked with a throttle opening / closing operation, and more particularly, to an ignition timing control structure for preventing the occurrence of ketting in such an engine.
[0002]
[Prior art]
As an outboard engine mounted on an outboard motor of a small vessel, the engine is manually started by a manual starter, and the ignition timing is controlled mechanically in conjunction with the operation for opening and closing the throttle. An engine in which a shift mechanism for switching the transmission of engine power between neutral, forward and reverse is moved through each connecting member such as a shift connecting lever by manual operation of a shift lever (shift operating lever). Conventionally used in general.
[0003]
[Problems to be solved by the invention]
By the way, in the engine as described above, when starting the engine manually with a manual starter, the engine should be started with the throttle fully opened in order to reduce the intake resistance and reduce the burden of the starting operation. In such a case, the ignition timing control is mechanically linked to the operation for opening and closing the throttle, so that the ignition advance is advanced by the accelerator operation for fully opening the throttle. Become.
[0004]
As a result, the ignition timing is advanced in spite of the low power to rotate the engine for manual start, and the piston is pushed back by starting ignition until the piston reaches top dead center. So-called ketting may occur where the engine rotates in reverse.
[0005]
The technique for preventing the occurrence of ketchin at the start of the engine is conventionally known, for example, in Japanese Patent Laid-Open Nos. 5-60044 and 7-259711. Each of the conventionally known ketchin prevention structures is costly because the ignition timing is electrically controlled using a microcomputer.
[0006]
An object of the present invention is to solve the above-described problems. Specifically, in an engine in which ignition timing control is mechanically interlocked with throttle opening / closing operation, it is reduced by a simple structure. It is an object of the present invention to be able to prevent the occurrence of ketchin at the start of the engine at a cost.
[0007]
[Means for Solving the Problems]
In the present invention, in order to solve the above-described problems, the ignition timing is controlled mechanically in conjunction with the throttle opening / closing operation, and the shift mechanism is moved via the shift coupling lever by the operation of the shift operation lever. In such an engine, an advance lever for linking the throttle opening / closing operation and ignition timing control is connected to a throttle opening / closing accelerator cam rotated by an accelerator operation with a predetermined coupling force via a spring force. It is provided coaxially so as to follow a predetermined range at the same time, and when the throttle mechanism opens the throttle in a neutral state, it is used for the advance angle with respect to the rotation of the accelerator cam against the connecting force with the accelerator cam. In order to limit the follow-up of the lever, a stopper that can contact the shift connecting lever in the neutral state is provided integrally with the advance lever. It is an.
[0008]
According to such a configuration, when the engine is started with the shift set to neutral and the throttle fully opened, even if the accelerator cam is rotated so that the throttle is fully opened by the accelerator operation, the advance angle lever is integrated. The stopper provided is in contact with the shift connecting lever in the neutral state, so that the rotation of the advance angle lever that follows the rotation of the accelerator cam is suppressed by the shift connecting lever, and the ignition advance angle is suppressed. Since the ignition timing cannot be advanced, ketting does not occur even if the engine rotational force at the time of starting is low.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an ignition timing control structure for an engine according to the present invention will be described below with reference to the drawings.
[0010]
FIG. 1 schematically shows an outboard motor equipped with an engine having an ignition timing control structure according to the present invention. The outboard motor 1 includes a top cowl 2, an upper case 3, a lower case 4, and a housing. The engine 5 serving as a drive source is housed in the top cowl 2, the steering handle 6 is connected to the upper case 3 via the steering bracket 7, and the propeller 8 serving as a propulsion device is disposed behind the lower case 4. A shift operation lever 9 is provided in the vicinity of the steering handle of the steering bracket 7 for manually switching the shift.
[0011]
The engine 5 housed in the top cowl 2 of the outboard motor 1 is installed so that the axis of the crankshaft (not shown) is in the vertical direction, and the upper end side of the crankshaft of the engine 5 is A manual starter 10 for starting the engine by a driver's manual operation is connected, and a drive shaft 11 for power transmission is connected to the lower end side of the crankshaft of the engine 5.
[0012]
A drive shaft 11 connected to the lower end of the crankshaft of the engine 5 extends vertically through the upper case 3 to the lower case 4. The lower end of the drive shaft 11 is connected to the propeller shaft via a shift mechanism 12 using a bevel gear. 13, the rotation of the crankshaft driven by the engine 5 is transmitted to the propeller 8 disposed on the rear side of the lower case 4 via the drive shaft 11, the shift mechanism 12, and the propeller shaft 13.
[0013]
Although not shown in detail, the shift mechanism 12 meshes the forward gear and the reverse gear, which are rotatably provided on the propeller shaft 13, with the drive gear fixed to the lower end of the drive shaft 11, respectively. The dog clutch, which is spline-engaged on the propeller shaft 13 between the gears, is shifted to the neutral, forward, or reverse position by the rotation of the shift cam provided at the lower end of the shift rod 14, thereby driving The rotation of the shaft 11 is transmitted to the propeller shaft 13 either forward or backward, or is not transmitted as neutral.
[0014]
The shift rod 14 is rotatably accommodated from the top cowl 2 into the steering shaft (an outer cylindrical member fixed integrally with the swivel bracket 17) in a state substantially parallel to the drive shaft 11, and the upper end thereof is the steering bracket. 7) is extended vertically to the lower case 4 through the hollow shaft core portion, and the upper end portion of the shift rod 14 is connected to the shift operating lever 9 via each connecting member. When the driver manually operates the shift operation lever 9, the shift rod 14 is rotated about its axis via the connecting members.
[0015]
In the outboard motor 1, a swivel bracket 17 is connected to a clamp bracket 16 that is detachably fixed to the rear plate 15 of the hull so that the swivel bracket 17 is pivotable in the vertical direction by a horizontal tilt shaft 18. 17, the outboard motor 1 is rotatably supported in the left-right direction (that is, the steering shaft of the outboard motor extending in the up-down direction is rotated inside the outer cylinder member integrally fixed to the swivel bracket 17. The hull stern plate 15 can be rotated in the up and down direction (tilt direction) and the left and right direction (steering direction). Is attached to.
[0016]
2 to 6, the connecting member between the shift operation lever 9 and the shift rod 14 is configured as one of the constituent members in order to control the ignition timing of the engine 5 of the outboard motor 1 as described above. The engine ignition timing control structure of the present embodiment shows different throttle opening states at each of the neutral and forward shifts.
[0017]
As shown in FIG. 2, the shift operation lever 9 is linked to the upper end portion of the shift rod 14 via the shift connecting rod 21 and the shift connecting lever 22 so that the driver manually performs the shift operation. The shift rod 14 is rotated by moving the shift connecting rod 21 forward and backward by operating the lever 9 and rotating the shift connecting lever 22 by moving the shift connecting rod 21 forward and backward.
[0018]
A throttle opening / closing accelerator that is rotated via an accelerator wire 23 by an operation of an accelerator operating portion provided on the steering handle is located above the shift connecting lever 22 for interlocking the shift operating lever 9 and the shift rod 14. A common base member 28 in which a cam 24 and an advance lever 27 movably connected via a connecting arm 26 and a pickup unit 25 of an advance device for controlling ignition timing are fixed at a fixed position. Are provided coaxially so as to be rotatable.
[0019]
Although the accelerator cam 24 and the advance lever 27 which are relatively rotatable and coaxially provided are not shown, one end of a coil spring arranged concentrically with the rotation shaft is rotated by the accelerator cam 24. By being fixed to the moving base portion side and the other end being fixed to the rotating base portion 29 side of the advance lever 27, the spring force in the torsion direction of the coil spring can be used with a predetermined coupling force. It is linked so that it can be linked.
[0020]
Further, with respect to the stopper receiving portions 28a and 28b formed on the base member 28 in order to restrict the rotation of the advance lever 27 within a predetermined range, the rotation base 29 of the advance lever 27 includes An integrally fixed stopper 30 and a stopper 31 that can be adjusted by a screw are integrally provided, and further, the accelerator cam in the neutral state so as to come into contact with the shift connecting lever 22 in the neutral state. A stopper 32 for restricting the follow-up of the advance angle lever 27 with respect to the rotation of 24 is integrally provided.
[0021]
The operating state of the engine ignition timing control structure of the present embodiment having the above-described structure will be described below with reference to FIGS.
[0022]
In a state where the shift is moved forward (F) by the operation of the shift operation lever 9, as shown in FIGS. 4 to 6, the shift connecting lever 22 is tilted forward and the advance angle lever 27 is rotated. Even so, the stopper 32 provided integrally with the rotation base 29 is not in contact with the shift connecting lever 22. Even when the shift is reverse (R), the direction in which the shift connecting lever 22 is tilted is reversed, and the relationship between the stopper 32 and the shift connecting lever 22 is the same as when the shift is forward (F). is there.
[0023]
In such a state other than neutral, when the accelerator cam 24 is rotated through the accelerator wire 23 by the accelerator operation, the accelerator cam 24 is rotated to open and close the throttle valve 33 regardless of the shift connecting lever 22. In conjunction with the operation, the advance lever 27 is formed by the stopper receiving portions 28 a and 28 b formed on the base member 28 and the stoppers 30 and 31 provided on the rotation base 29 of the advance lever 27. In the regulated predetermined rotation range, the accelerator cam 24 rotates following the rotation.
[0024]
That is, when the throttle is closed, as shown in FIG. 4, the stopper receiving portion 28b on the base member 28 side and the stopper 31 on the advance angle lever 27 side come into contact with each other, so that the advance angle lever 27 rotates counterclockwise. , And the stopper 30 on the advance angle lever 27 side prevents the accelerator cam 24 from rotating counterclockwise, so that the advance lever 27 and the accelerator cam 24 are The member 28 is stopped at a fixed initial position adjusted by a stopper 31 that can be adjusted by a screw.
[0025]
When the accelerator operation is performed so that the throttle is opened from the closed state, the accelerator cam 24 and the advance lever 27 are connected by a coil spring interposed therebetween as shown in FIG. Until the stopper receiving portion 28a on the base member 28 and the stopper 30 on the advance angle lever 27 come into contact with each other, the advance angle lever 27 follows the rotation of the accelerator cam 24, and the throttle valve 33 has a predetermined opening (partial). The advance lever 27 is rotated until the ignition timing reaches the ignition timing suitable for the operating state of the engine (advanced by θ1-θ2).
[0026]
Further, when the accelerator operation is performed so that the throttle is fully opened from the partial state, the stopper receiving portion 28a on the base member 28 side and the stopper 30 on the advance angle lever 27 side are brought into contact with each other as shown in FIG. The advance angle lever 27 does not rotate further in the clockwise direction, and the advance angle (θ1-θ2) of the ignition timing does not advance any more, whereas it is rotated through the accelerator wire 23. The accelerator cam 24 is rotated to a position where the throttle valve 33 is fully opened against the spring force of a coil spring interposed between the accelerator cam 24 and the advance lever 27.
[0027]
In the state where the shift is neutral as compared to the state where the shift as described above is forward (F), the shift connecting lever 22 is in a standing state as shown in FIGS. When the accelerator operation is performed so that the throttle is opened from the throttle closed state, the advance lever 27 that follows the accelerator cam 24 that is rotated via the accelerator wire 23 rotates the advance lever 27. The stopper 32 provided integrally with the rotation base 29 abuts the shift connecting lever 22 to advance only a little (θ1−θ3), and the advance angle position (θ1−1) when the throttle is fully opened. It will be regulated so that it does not reach θ2).
[0028]
That is, when the throttle is closed, as shown in FIG. 2, the advance lever 27 and the accelerator cam 24 stop at a fixed initial position with respect to the base member 28, as in the case where the shift is forward (F). However, if the accelerator operation is performed so that the throttle is opened from such a closed state, as shown in FIG. 3, the stopper receiving portion 28a on the base member 28 side and the advance lever 27 side are still on. In a state where the stopper 30 is not in contact, the stopper 32 on the advance angle lever 27 side contacts the shift coupling lever 22.
[0029]
Then, at that time, the advancement lever 27 rotates against the spring force of the coil spring interposed between the accelerator cam 24 and the advancement lever 27 to follow the rotation of the accelerator cam 24. Even if the accelerator operation is performed until the throttle is fully opened from such a state, the accelerator cam 24 is rotated and the throttle is fully opened. The rotation of the advance angle lever 27 remains at the advance angle position (θ1-θ3) stopped by the shift connecting lever 22, and does not proceed further.
[0030]
According to the ignition timing control structure of the engine of the present embodiment that operates as described above, a simple structure is provided in which the stopper 32 for bringing the advance lever 27 into contact with the shift connecting lever 22 is provided. Thus, when the engine 5 is started with the throttle fully open, even if the accelerator cam 24 is rotated by the accelerator operation, the stopper 32 provided integrally with the advance lever 27 is provided when the shift is in the neutral state. By contacting the shift connecting lever 22, the rotation of the advance angle lever 27 following the rotation of the accelerator cam 24 is suppressed, and as a result, the advance angle of ignition is suppressed and the ignition timing cannot be advanced. Even if the engine rotational force at the time of starting is low, ketting does not occur.
[0031]
As mentioned above, although one embodiment of the ignition timing control structure of the engine of the present invention has been described, the present invention is not limited only to the embodiment as described above. For example, the engine shown in the above embodiment Although it is an engine for an outboard motor, it can be implemented even with an engine other than that for an outboard motor, and the engine shown in the above embodiment uses a manual starter as a starter for starting the engine. Needless to say, the present invention can be changed as appropriate, for example, in an engine using an electric starter.
[0032]
【The invention's effect】
According to the ignition timing control structure for an engine of the present invention as described above, even when the engine is started with the throttle fully open, it is possible to prevent the occurrence of kettin at the time of starting, and to prevent the ketchin. Therefore, the ignition timing can be controlled at a low cost with a very simple structure.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing an outboard motor equipped with an engine equipped with an ignition timing control structure of the present invention.
FIG. 2 is a side view showing a state in which the shift is neutral and the throttle is closed according to an embodiment of the engine ignition timing control structure of the present invention.
FIG. 3 is a side view showing a state where the shift is neutral and the throttle is fully open in the engine ignition timing control structure shown in FIG. 2;
4 is a side view showing a state in which the shift is forward (F) and the throttle is closed in the engine ignition timing control structure shown in FIG. 2; FIG.
FIG. 5 is a side view showing a state where the shift is forward (F) and the throttle is partial in the engine ignition timing control structure shown in FIG. 2;
6 is a side view showing a state in which the shift is forward (F) and the throttle is fully opened in the engine ignition timing control structure shown in FIG. 2; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outboard motor 5 Engine 9 Shift operation lever 10 Manual starter 12 Shift mechanism 22 Shift connection lever 24 Acceleration cam 27 Advance angle lever 32 Stopper 33 (it contacts shift connection lever) Throttle valve

Claims (2)

In an engine where the ignition timing is controlled mechanically in conjunction with the throttle opening / closing operation, and the shift mechanism is moved via the shift connecting lever by operating the shift operation lever, the throttle opening / closing operation and ignition timing control are linked. An advance angle lever is provided coaxially so as to follow a predetermined range with a predetermined coupling force via a spring force with respect to a throttle opening / closing accelerator cam rotated by an accelerator operation. In addition, when opening the throttle when the shift mechanism is in the neutral state, in the neutral state so as to limit the follow-up of the advance lever against the rotation of the accelerator cam against the coupling force with the accelerator cam. An ignition timing system for an engine, characterized in that a stopper capable of contacting the shift connecting lever is provided integrally with the advance angle lever. Structure. 2. The engine ignition timing control structure according to claim 1, wherein the starter for starting the engine is a manual starter by manual operation.

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