JPH0723709B2 - Method of controlling ignition timing and auxiliary exhaust valve of two-cycle engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a two-cycle engine for a motorcycle including a spark plug, a main exhaust valve, and an auxiliary exhaust valve that is opened by advancing during acceleration (the present specification). (Also referred to as an internal combustion engine), and a method for controlling the auxiliary exhaust valve.

(Prior Art) In a two-cycle engine or the like mounted on a motorcycle or the like, generally, an automatic advance device is attached and the ignition timing is adjusted according to the speed (rotation speed) of the engine. This adjustment, for example, as shown by the solid line Pb in FIG. 3, advances or delays the ignition timing according to the engine speed so that optimum combustion can be performed at that rotation speed. As such a prior art, there is JP-A-62-75072.

The automatic advance device has traditionally been of a type using a governor mechanism, and has recently been configured using a computer.

(Problems to be Solved by the Invention) By the way, in recent years, engine performance has been remarkably improved, and particularly in recent years, there have been some remarkable things.

However, even today, further improvement in engine performance is required. One of them is the acceleration performance or response performance of high-speed vehicles such as motorcycles.

However, in the case of the automatic advance device as described above, since the ignition timing is simply changed in accordance with the absolute speed, in the acceleration state or the deceleration state, in the combustion chamber of the engine, There are some areas where optimal combustion is not always performed.

The present invention has been made under the background described above, and an object thereof is to provide an engine excellent in acceleration performance and response performance.

(Means for Solving the Problem) A method for controlling an ignition timing and an auxiliary exhaust valve of a two-cycle engine according to the present invention includes a spark plug, a main exhaust valve, and an auxiliary exhaust valve that is advanced and opened during acceleration. In a method for controlling an ignition timing and an auxiliary exhaust valve of a two-cycle engine for a motorcycle, an engine acceleration (increase / decrease in engine speed per unit time) is detected, and a degree of the detected engine acceleration is determined. Then, according to the degree of the acceleration, a corresponding advance angle correction process is selected from a plurality of advance angle correction processes having different advance angles to change the ignition timing, and when the acceleration is positive, the acceleration is changed to the acceleration. The feature is that the opening timing of the auxiliary exhaust valve is advanced accordingly.

(Operation) In this way, the acceleration of the engine is detected, the degree of acceleration of the detected engine is determined, and a corresponding advance angle correction process is selected according to the degree of acceleration to vary the ignition timing. When the acceleration is positive, advancing the opening timing of the auxiliary exhaust valve in accordance with the acceleration causes the combustion state and exhaust efficiency at each rotation speed to remarkably change as compared with the conventional one, so that the output during acceleration is improved. At the same time, the capacity of the control device can be reduced.

(Embodiment) FIG. 1 is an overall configuration diagram showing a schematic configuration of the engine according to the present embodiment, FIG. 2 is a block diagram showing a configuration of an igniter and connections with peripheral devices, and FIG. 3 is an ignition timing. FIG. 4 (a), (b), (c) showing the relationship between the rotation speed and the rotation speed.
Is a flow chart showing the control contents of the ignition timing, and FIGS. 5 (a) and 5 (b) are partially enlarged views showing the internal structure of the cylinder upper part of the two-cycle engine according to the present embodiment.

In FIG. 1 or FIG. 5 (a), 1A is a cylinder head, and 2 spark plugs are provided on the cylinder head 1A.
Is installed. As shown in FIGS. 1 and 2, the ignition plug 2 is electrically connected to an igniter 3 which supplies a current for ignition at a predetermined time. The igniter 3 is electrically connected to a sensor 5 attached to the generator 4 so that the engine speed can be measured.

In addition, the two-cycle engine according to the present embodiment has a fifth
Auxiliary exhaust port 10, auxiliary exhaust passage 11, and auxiliary exhaust valve 12 for expanding the exhaust passage in the high speed region and improving the exhaust efficiency in the high speed region as shown in FIG. An auxiliary exhaust system consisting of is provided in the cylinder 1B. In addition to the auxiliary exhaust system, the main exhaust port
A main exhaust system including a main exhaust passage 13 and a main exhaust passage 14 is provided in the cylinder 1B. The auxiliary exhaust passage 11 joins the main exhaust passage 14 on the outside air side, and the main exhaust passage 14 is connected to an exhaust pipe (not shown).

Further, the auxiliary exhaust system is configured so that this passage is communicated / blocked by the rotational movement of the auxiliary exhaust valve 12, and the rotational movement is driven by the drive motor 15 shown in FIGS. 1 and 2. . This auxiliary exhaust valve 12 (Fig. 5 (b)
The drive motor 15 and the drive motor 15 are mechanically connected to each other via a transmission mechanism such as a wire 16 and an ear 17, as shown by a chain double-dashed line in FIG. "Open" and "Closed" (see Figs. 5 (a) and 5 (b))
It is configured so that the switching operation can be performed. Further, a potentiometer 18 is attached to a rotation shaft (not shown) of the drive motor 15 so that the igniter 3 can detect the rotation angle of the drive motor 15.

The drive motor 15 and the potentiometer 18 are electrically connected to the igniter 3, as shown in FIG.

Then, the ignition timing of the spark plug 2 and the drive motor 15 of the auxiliary exhaust valve 12 are changed according to the acceleration of the engine.
It is controlled by the igniter 3.

This control is performed by the program stored in the memory of the igniter 3 as shown in the flowcharts of FIGS. 4 (a), (b) and (c).

(A). That is, as shown in the flowchart of FIG. 4 (a), the igniter 3 detects the engine speed Rn at that time by the sensor 5 at every constant timing, and calculates the engine acceleration α at that time. .

(B). Regarding the ignition timing control, as shown in the flowchart of FIG.
It is determined whether the absolute value of is larger than the acceleration to be controlled. When the absolute value of the acceleration is large, the ignition timing of the spark plug 2 is changed according to the acceleration α to the line P _{1 in} FIG.
~ As shown by P ₃ , the reference ignition timing Pb (solid line in Fig. 3
The ignition timing advance angle is varied with respect to Pb). That is, in the present embodiment, the magnitude of the detected acceleration α is set in three predetermined levels (α ₁ rpm / sec.α ₂ rpm / sec.α ₃ rpm / sec).
It is determined which range of 3
The advanced angle correction angle p (p ₁ °, p ₂ °, p ₃ °) divided into stages is selected and controlled so as to be advanced (advanced) by that amount from the reference ignition timing Pb at that speed ( However, p ₁ <p ₂ <p ₃ ). Of course, if the capacity of the control device can be increased, the acceleration α may be made stepless like the control of the auxiliary exhaust valve 12 described later. Further, the advance amount may not be a fixed correction amount but may be changed according to the engine speed.

On the other hand, when the acceleration α is “negative”, contrary to the above control, in the present embodiment, it becomes P ₀ ° before the top dead center (delays).
Control (however, P ₀ <Pb).

In this way, when control is performed to make the ignition timing earlier or later than the reference ignition timing, generally, in the acceleration state, the air-fuel ratio is high in the combustion chamber (fuel ratio is high), so if the ignition timing is made earlier than the reference ignition timing, Combustion efficiency improves and output improves. Further, during deceleration, the output of the engine can be reduced by delaying the reference ignition timing.

(C). Regarding the control of the auxiliary exhaust valve 12, as shown in the flow chart of FIG. 4 (c), when the acceleration α is “positive”, the engine speed R _{0 is set} to the specific rotation speed R ₀ according to the acceleration α. On the other hand, how much the rotational speed R ₁ of the auxiliary exhaust valve 12 at the beginning of opening is accelerated is calculated. In the case of the present implementation order, this calculation is based on the above-mentioned specific rotational speed (auxiliary exhaust passage It refers to a rotational speed to exert a remarkable effect) operation to conform to the R ₀ are made open. For example, suppose that the operating time is T
(Sec) and the acceleration in the rotational speed range before advance of the specific rotational speed R ₀ is α (rpm / second), the rotational speed R ₁ (rpm) at which the auxiliary exhaust valve 12 starts to open is R ₁ = [R ₀ −T · α / 2] (1) That is, as indicated by a thin line C in the time chart of FIG. 7, the auxiliary exhaust valve 12 is started to be opened after being corrected so as to be faster than the specific rotation speed R ₀ by [T · α / 2] (rpm).

As for the opening start timing of the auxiliary exhaust valve 12, whether the rotation speed Rn at that time obtained by the sensor 5 is called every moment as shown in the flowchart of FIG. 4 (a) and the rotation speed Rn becomes equal to the obtained R ₁ Check whether or not the rotation speed Rn is R ₁
Is equal to, the auxiliary exhaust valve 12
By issuing a command to open the.

When the potentiometer 18 confirms that the auxiliary exhaust valve 12 is in the fully open state, the turning operation of the auxiliary exhaust valve 12 is terminated by instructing the drive motor 15 to stop.

As mentioned above, depending on the acceleration at that time, the specific rotation speed
By opening the auxiliary exhaust valve 12 earlier than R ₀ by the above correction amount, exhaust efficiency is improved and output characteristics can be made smooth. In particular, as described above, the midpoint of the operating time of the auxiliary exhaust valve 12 is set to match the specific rotation speed R ₀ ,
When the opening / closing operation of the auxiliary exhaust valve 12 is controlled, the sixth
As indicated by a thin line A in the figure, the output characteristic can be smoothed around both sides of the specific rotation speed R ₀ .

In the above embodiment, the opening / closing operation of the auxiliary exhaust valve 12 is controlled so that the midpoint of the operating time of the auxiliary exhaust valve 12 matches the specific rotation speed R _0. By correcting the point at which the valve 12 starts to open earlier than the specific rotational speed R ₀ within the range of the operating time of the valve, the output compared with the output characteristic (broken line A ′) of the conventional two-cycle engine of this type. The characteristics can be smoothed.

On the other hand, when decelerating from a rotational speed range higher than the specific rotational speed (when the acceleration is negative), control is performed so that the auxiliary exhaust valve is closed, as shown in the latter part of the flowchart of FIG. 4 (c). .

In this embodiment, as described above, the ignition timing and the auxiliary exhaust valve are controlled so as to fluctuate according to the acceleration of the engine. Therefore, due to the synergistic effect of these, a better response performance in acceleration performance at the time of acceleration is obtained. can get.

The flow charts in FIGS. 4 (a) to 4 (c) are as follows.
The time processing may be appropriately timed and multiple CPUs may perform multiple processes. If necessary, multiple CPUs may be used to perform simultaneous processes.

Further, in FIG. 6, a two-dot chain line A ″ shows the output characteristic of an engine of a type that does not have an auxiliary exhaust valve.

Further, in the above-mentioned embodiment, although the description has been made exclusively for the two-cycle engine, it is needless to say that the control method according to the present invention can be applied to the four-cycle engine in the same manner as above and has the same operational effect.

(Effects of the Invention) According to the present invention, since the ignition timing and the auxiliary exhaust valve are controlled as described above, it is possible to provide an engine which is superior in acceleration and response as compared with the conventional engine.

Therefore, for example, when the present engine is mounted on a high-speed traveling vehicle such as a motorcycle, it is possible to provide a vehicle excellent in drivability without feeling insufficient output in all rotation regions.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a schematic configuration of the engine according to the present embodiment, FIG. 2 is a block diagram showing a configuration of an igniter and a connection with a controlled object, and FIG. 3 is an ignition timing and a rotation. FIG. 4 (a), (b), (c) showing the relationship with the number
Is a flow chart showing the control contents of the igniter, FIG. 5 (a) is a partially enlarged view showing the internal structure of the cylinder upper part of the two-cycle engine according to this embodiment, and FIG. 5 (b) is that of FIG. 5 (a). FIG. 6 is a view showing the engine speed-output characteristic, and FIG. 7 is a view showing the relationship between the opening / closing timing of the auxiliary exhaust valve and the engine speed. 1A: Cylinder head, 2 ... Spark plug, 3 ... Igniter, 4 ... Generator, 5 ... Sensor.

Claims (1)

[Claims] 1. A method for controlling an ignition timing and an auxiliary exhaust valve of a two-cycle engine for a motorcycle, comprising a spark plug, a main exhaust valve, and an auxiliary exhaust valve which is advanced and opened during acceleration. Is detected, the degree of acceleration of the detected engine is determined, and a corresponding advance angle correction process is selected from a plurality of advance angle correction processes having different advance angles according to the degree of acceleration, and ignition is performed. A method for controlling an ignition timing and an auxiliary exhaust valve of a two-cycle engine, which comprises changing the timing and advancing the opening start timing of the auxiliary exhaust valve according to the acceleration when the acceleration is positive.