JPS6232262A - Internal combustion engine controller - Google Patents

Abstract

PURPOSE:To eliminate unnecessary control over a controlled device at the time of idling when some variations occur in revolution, by making the control of a part, where the controlled device largely varies to a slight variation in rotational frequency of an internal combustion engine, have a hysteresis. CONSTITUTION:At an exhaust port 9 in a two-cycle engine 1, there is provided with a movable valve 10, and this movable valve, namely, a controlled device 10 is regulated its opening by an electronic control part 15 via a servomotor unit 11 on the basis of output of a pulser coil 16. And, the electronic control part 15 detects a revolving sped of the engine 1 with an engine speed detecting device 17, and calculates the value of opening in the movable valve 10 corresponding to the said revolving speed with a movable valve opening operational device 19. In this case, the movable valve opening operational device 19 is made to have a hysteresis in its control over a part where the controlled device 10 largely varies to a slight variation in the said revolving speed. Wit this constitution, it copes with rotational unevenness or the like at the time of idling, thereby eliminating unnecessary control over the controlled device 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an internal combustion engine control device that adjusts the opening of an exhaust valve or performs other controls in accordance with the rotational speed of the internal combustion engine.

[Conventional technology]

For example, a two-stroke internal combustion engine has an exhaust port that is opened and closed by a piston.

In such two-stroke internal combustion engines, there is one in which a movable valve as a controlled means is provided at the upper edge of the exhaust port, and the movable valve is driven based on a detection signal of the engine rotational speed to control the exhaust timing ( (Japanese Patent Application Laid-Open No. 15851/1983)
. In principle, this movable valve is controlled to have a large opening during high-speed rotation and a small opening during low-speed rotation, and this control improves the output of the engine.

On the other hand, if we look at the operation of this movable valve in more detail, we can see that this movable valve becomes fully open when the control device is powered on (when the engine speed is zero), and then immediately opens when the engine starts. The original control described above is performed. The reason why the valve is fully opened before the engine starts is to scrape off carbon deposited around the movable valve, or to initialize the opening degree in the fully open state.

[Problem that the invention seeks to solve]

In this way, the movable valve is controlled to shift from the fully open state to the original adjusted opening in the low engine speed region near zero, but the rotation speed is generally unstable when the engine is idling. Yes, there are variations in the rotational speed during the engine stroke. Therefore, the rotation speed is often very low when viewed instantaneously, and the rotation speed during idling temporarily matches the rotation speed at which the movable valve changes from the fully open state to its original adjusted opening. This often happens. If this situation is left unaddressed, the movable valve will open and close unnecessarily during idling.
There were drawbacks such as wasted power consumption.

[Means for solving problems]

The present invention has been made in view of the above problems, and the relationship between the rotational speed and the position of the controlled means is set in advance, and the controlled means changes in response to a slight change in the rotational speed within the relationship. Hysteresis is added to the control of parts that change significantly.

[Operation] Even if the rotational speed of the controlled means changes temporarily due to irregular rotation during idling, etc., the position of the controlled means changes due to hysteresis. does not change.

〔Example〕

Hereinafter, the present invention will be described in detail along with examples.

FIG. 1 is a block diagram showing an embodiment of the present invention.

2 is a two-stroke engine, 2 is a cylinder, 3 is a piston, and 4 is a crankshaft. An intake passage 5 for introducing a fuel mixture gas is connected to the lower part of the cylinder 2, and a throttle valve 6 for adjusting the amount of intake air is provided in the intake passage 5. A combustion chamber 2a formed in the upper part of the cylinder 2 is provided with a spark plug 7 on its upper surface, and has a scavenging port 8 and an exhaust port 9 opened on its side surface. A movable valve 10 that can change the area of the exhaust port is provided at the upper edge of the exhaust port 9, so that the exhaust timing can be controlled. That is, the movable valve 10 has a semi-cylindrical shape that is divided into two on a plane including the central axis, and by rotating about the central axis, the position of the edge facing the exhaust port 9 is vertically displaced. This is to adjust the exhaust timing.

The opening degree of the movable valve 10 is adjusted by a servo motor unit 11. The servo motor unit 11 includes a servo motor 12, a potentiometer 13 that converts the rotation angle of the servo motor 12 into an electric signal, and a pulley drive device that transmits the rotation force of the servo motor 12 to the movable valve 10 via the wire 8. It consists of 14.

The electronic control section 15 controls the servo motor unit 11 based on the output of the pulsar coil 16. When this device is mounted on a motorcycle, the electronic control section 15 controls the servo motor unit 11 based on the output of the pulser coil 16. It is housed in the space together with the servo motor unit 11. Electronic control section 15
is composed of a microcomputer consisting of a CPU, a memory section, and an interface section, and when divided into functional blocks, it consists of a rotational speed detection means 17, a movable valve opening calculation means 19, a movable valve opening comparison means 20, and a motor. It can be divided into control means 21.

The rotational speed detection means 17 is a means for detecting the rotational speed R of the engine 1 by counting the number of pulses of the pulsar coil 16 per unit time, detecting the period of output pulses of the pulsar coil 16, etc.

The movable valve opening calculation means 19 is a means for calculating the opening θ of the movable valve 10 corresponding to the rotational speed R. here,
The relationship between the engine rotational speed R and the movable valve opening degree θ will be explained.

FIG. 3 is a characteristic diagram showing the relationship between engine rotational speed R and engine output when the movable valve opening degree is changed. Solid lines A, B, and C indicate the opening degrees of the movable valves θa, θb, and θC (
However, the engine output is shown when θa<θb<θC, and the broken line is the envelope of these characteristic curves.

As can be seen from the figure, when the engine speed R is below Ra, the movable valve opening is set to the minimum opening θa (solid line A), and when the engine speed R is below Ra, the maximum opening θC ( When the rotational speed R is between Ra and RcO, the maximum output according to the rotational speed R can be obtained by setting the movable valve opening to an appropriate opening between θa and θC. This is possible.

On the premise of such an action, the movable valve opening degree calculation means 19 calculates and outputs the movable valve opening degree θ in order to obtain the maximum output. Fourth
The figure is a graph showing the relationship between the rotational speed R and the movable valve opening θ.When the rotational speed R is other than around zero, the movable valve opening θ is adjusted so that the engine output is maximized. It shows that there is. Further, when the rotational speed R is zero, the movable valve 10 is fully open (maximum opening degree θC) as described above, so the rotational speed R is close to zero.

The opening degree is set to change greatly from the maximum opening degree θC to the minimum opening degree θa.

The movable valve opening calculation means 19 basically calculates the movable valve opening θ based on this relationship, but the rotational speed RO
After i'ii7, processing is performed with hysteresis.

This hysteresis processing will now be explained.

FIG. 5 is a graph specifically showing the hysteresis process by expanding the "rotational speed R--movable valve opening characteristic" near the rotational speed RO in the direction of the rotational speed R.

In the same figure, the rotational speed near RO is Rz, Rx (R2
<Ro<R+), and the average rotational speed during idling is R1 (R:l<R1).

As mentioned above, the rotational speed during idling is unstable, so even if the average rotational speed is Ro, if you look at the instantaneous speed during one stroke of engine rotation, it will be a value lower than Ro ( For example, R,) is often taken. Therefore, if the movable valve opening degree θ is directly calculated and output based on the characteristics shown in FIG. 4, there is a risk that opening and closing may be repeated pointlessly during idling. However, the movable valve opening calculation means 19 of this embodiment has hysteresis with a width of ±α when changing the movable valve opening θ from θa to θC or from θC to θa when the rotational speed R is near RO. At the same time, the value of the movable valve opening degree θ is output. Therefore, even if there is a change in the rotational speed that instantaneously crosses Ro, such as a variation in rotational speed during idling, the movable valve opening degree is maintained at θa, and the opening/closing operation of the movable valve 10 does not occur. In addition, it is possible that the average rotational speed R, becomes less than RO during idling in winter, but since hysteresis is provided, the rotation speed that momentarily crosses RO as in the case described above may occur. Even if there is a change in speed, the opening degree of the movable valve is maintained at θC, and the opening/closing operation of the movable valve 10 does not occur.

The thus calculated movable valve opening degree θ is input to the movable valve opening comparison means 20 and compared with the current movable valve opening degree θp obtained from data input from the potentiometer 13. That is, the movable valve opening comparison means 20 compares the opening difference (θ−
θp) and determines whether the value is positive, negative, or zero, and the determination result is output to the motor control means 21.

The motor control means 21 is a means for rotating the servo motor 12 in an appropriate direction according to the value of the opening degree difference (θ-θp), and when the opening degree difference (θ-θp) is positive, that is, (θ-θp)> If it is 0, it outputs a rotation signal that rotates the servo motor 12 in the forward direction so that the movable valve 10 opens, and if the opening difference is negative, that is, (θ - θ
p) If <0, output a rotation signal to reverse the servo motor 12. In addition, the opening difference is zero, that is, θ−θp=0
If so, the servo motor 12 outputs a rotation signal to maintain the stopped state.

The operations of the above-mentioned means in the electronic control unit 15 are actually executed by a single microcomputer, and a flowchart thereof is shown in FIG. First, the "rotational speed R--movable valve opening characteristic" as shown in FIG. The current movable valve opening degree θp is detected based on the information from 13 (steps 102 and 103).
).

Next, it is determined whether the rotation speed R is not in the low rotation range including RO (step 104). A concrete judgment as to whether or not it is in the low rotation region is made by comparing the rotation speed R with a suitable rotation speed R with a large value of the movable valve opening θ (larger than the changing rotation speed RO). R
-R≧0, the movable valve opening θ is determined based on the characteristics determined in process 101 (step 105). When it is determined in judgment 104 that it is in the low rotation region, that is, R-
If R1<O, hysteresis processing is performed when calculating the movable valve opening degree θ (step 106).

A specific routine for this time constant processing is shown in the flowchart of FIG. Now, if the engine is idling at an average rotational speed R, then the rotational speed is normally (R
Since it is near R1 which is larger than o+α), judgment 201
The process then proceeds to process 202, where the movable valve opening degree is set to θa, and the process proceeds to general flow determination 107.

Now, suppose that the rotational speed temporarily becomes R2 due to uneven rotation of the engine, the process proceeds from judgment 201 to judgment 203, and directly proceeds to general flow judgment 107. Therefore, the set value of the movable valve opening degree θ is maintained at the previous value θa, and the process proceeds to judgment 107, and the movable valve 1o does not rotate at all.

Similarly, when the movable valve opening degree is θC, the rotation speed R2
Even when the engine is in an idling state with the average rotational speed in the vicinity, the set value of the movable valve opening degree is maintained at θC even if the rotational speed instantaneously reaches R3 due to uneven rotation.

Next, the movable valve opening degree θ obtained in process 105 or 106
The difference between the opening degree θp of the movable valve obtained in step 103, that is, the opening difference (θ−θp) is determined (step 107), and θ−θp
>Q, rotate the servo motor 12 forward (step 1)
08), θ−θp=.

In this case, the servo motor 12 is stopped (step 109).
), and reversed when θ−θp<Q (step 110
). The above process is repeated continuously thereafter. Furthermore, processing 1
If the characteristic calculation of 01 is executed periodically at appropriate intervals, the influence of noise during data reading can be sufficiently removed, so in judgment 111 it is determined whether or not it is time to calculate the characteristic.
If it is not time to calculate the characteristics, the process directly advances to process 102.

In this embodiment, a movable valve provided at an exhaust port is used as an example of the controlled means, but it goes without saying that the present invention can be applied to other means as well.

〔Effect of the invention〕

As explained above, in the internal combustion engine control device of the present invention, the relationship between the rotational speed and the position of the controlled means is set in advance, and in this relationship, the controlled means changes in response to a slight change in the rotational speed. Since hysteresis is provided in the control of parts that change significantly, even if the actual rotational speed reaches a rotational speed that greatly changes the position of the controlled means, the position of the controlled means will remain unchanged unless the rotational speed greatly exceeds the rotational speed. does not change. Therefore, there is no need to drive the controlled means unnecessarily during idling or the like where there are variations in rotation, and there are advantages such as being able to prevent unnecessary power consumption.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a side view showing the arrangement when the present invention is mounted on a motorcycle, and Fig. 3 is an engine rotation when changing the opening degree of the movable valve. A characteristic diagram showing the relationship between the speed R and the engine output, FIGS. 4 and 5 are graphs showing the relationship between the rotational speed R and the movable valve opening θ, and FIG. 6 shows the execution of the electronic control unit 15. FIG. 7 is a flowchart of the hysteresis process similarly executed by the electronic control section 15. 1...2-cycle engine, 10...Movable valve, 11
...Servo motor unit, 15...Electronic control section. Patent Applicant Yamaha Motor Co., Ltd. Representative Kazuko Yamakawa (and 2 others)

Claims (1)

[Claims] In an internal combustion engine control device that adjusts the positional state of a controlled means according to the rotational speed of an internal combustion engine, the relationship between the rotational speed and the position of the controlled means is set in advance, and An internal combustion engine control device characterized by providing hysteresis in control of a portion where a controlled means changes significantly in response to a change.