JPH06102980B2 - Two-cycle engine control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control method for a two-cycle engine, and more specifically, it relates to a method for controlling a two-cycle engine, and more specifically, between an intake passage or an exhaust passage and a chamber formed in communication with these passages. The present invention relates to a method of controlling the operation of an interposed open / close valve.

[Prior art]

In a two-cycle engine, an exhaust chamber is made to communicate with the exhaust passage and the exhaust pulsation is used to improve the filling efficiency, or an intake chamber is provided in the intake pipe.
Various measures have been taken to improve engine output, such as increasing intake efficiency by utilizing pressure fluctuations in the intake pipe. FIG. 4 shows a method of controlling an exhaust valve which is interposed between an exhaust passage and an exhaust chamber and which connects and disconnects the passage and the chamber. The ignition pulse based on the rotation of the engine A is detected by the detector B to detect the engine speed. Then, the information on the engine speed from the detector B is branched into two, one is sent to the exhaust valve controller C and the other is sent to the ignition timing controller D. The ignition timing controller D determines the optimum ignition timing based on the engine speed and sends this ignition timing signal to the magneto E. Magneto E supplies a high voltage to the spark plug based on the above ignition timing signal,
Hereinafter, engine A, detector B, ignition timing controller D,
By circulating the signal between the magnetos D, the engine A is efficiently operated. On the other hand, in the exhaust valve controller C to which the engine speed information is sent from the detector B, the input engine speed value is compared with a certain preset threshold value, and if the engine speed value is lower than the threshold value, An exhaust valve open signal, an exhaust valve close signal is generated when the engine speed value is higher than a threshold value, and this signal is sent to the motor F. The motor F operates the exhaust valve G in the open state or the closed state based on the signal, and the engine is efficiently operated by the control method.

By the way, as described above, in the case where the operation control of the exhaust valve is performed depending on the magnitude of the engine speed numerical value with respect to the threshold value, it may not be possible to cope with the operating condition of the engine. For example, with an exhaust chamber that adopts the above control method 2
If you suddenly decelerate a motorcycle equipped with a cycle engine from the state where you are currently traveling at high speed, the throttle will be throttled for deceleration and the intake passage will be closed, while the engine,
In other words, the crankshaft continues to rotate at a value higher than the threshold value due to the rear wheels that continue to rotate due to the inertia of the vehicle body that was running at the speed before deceleration, so the exhaust valve remains closed and exhaust gas remains in the exhaust passage. Is done smoothly. In such a state, although the fuel is not sent into the combustion chamber, the exhaust is smoothly performed, so that the lubricating oil in the combustion chamber is also discharged, and the cylinder, the piston, and even the exhaust valve described above are exhausted. It was exposed to high temperatures and there was a risk of burning.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object thereof is to provide a control method for a two-cycle engine capable of efficiently operating an engine in response to various operating conditions.

[Structure of Invention]

Therefore, in the present invention, the opening / closing valve interposed between the intake / exhaust passage and the chamber communicating with the passage is opened while the engine speed is lower than a preset threshold value, while the engine When the engine speed is higher than the threshold value, the engine is opened, and when the engine speed is higher than the threshold value and the rate of decrease of the engine speed per unit time is greater than a preset value of the rate of decrease. Has
The above object is achieved by controlling the operation so that the on-off valve is opened.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment.

1 and 2 show the operating conditions of a two-cycle engine operated based on the control method according to the present invention, and
6 is a block diagram showing a control method in an exhaust valve controller (see FIG. 4). The overall control of the engine is based on the conventional control method described with reference to FIG.

If the engine is currently in operation, that engine,
In other words, the rotation speed of the crankshaft is detected by the detector B (4th
(See the figure), the engine speed information from the detector B is converted into the ignition timing signal of the ignition timing controller D, and the ignition plug is actuated by the high voltage generated by the magneto E based on the ignition timing signal. However, this controls the engine operation. On the other hand, the engine speed information a from the detector B is sent to the ignition timing controller D and also to the exhaust valve controller 1. The engine speed information sent to the exhaust valve controller 1 is input to a frequency-voltage converter 2 (hereinafter referred to as / V converter 2) without any choice, as shown in FIG. , Is converted into a voltage value proportional to the rotation speed. This voltage value is branched into two, one of which is sent to a differentiating circuit 3 and the other of which is sent to a comparing circuit I4. The voltage value input to the comparison circuit I4 is
A value preset in I4, that is, a threshold value for selecting the opening / closing operation of the exhaust valve according to the magnitude of the engine speed, is compared, and if the engine speed is lower than the threshold value, a logic level "1" signal is output. , If the engine speed is higher than the threshold value, a signal of logic level "0" is output from the comparison circuit I4.
Output from the logic level signal of "1" or "0"
It is sent to the OR circuit 5. On the other hand, the voltage value indicating the engine speed sent from the / V converter 2 to the differentiating circuit 3 is output as a differential value, in other words, as a rate of voltage change per unit time. This differential value is then sent to the comparison circuit II6. A differential value in a certain deceleration state, in other words, a deceleration gradient is set in advance in this comparison circuit II6, and the differential value from the differentiation circuit 3, that is, the speed gradient, is abruptly decelerated than the preset deceleration gradient. In this case, a logic level "1" signal is output, and during slow deceleration other than the above and during acceleration or constant speed operation, a logic level "0" signal is output. These "1" or "0" logic level signals are input to the OR circuit 5 together with the logic level signals output from the comparison circuit I4 described above. The OR circuit 5 determines the conditions of the engine speed range and speed gradient, outputs an operation signal based on the conditions, and the motor 7 operates according to the operation signal to open / close the exhaust valve.

When the engine starts operating and the engine speed is low and the threshold value N has not been reached, as shown in the left side of FIG. 1, a signal of logic level "1" is output from the comparison circuit I4. Further, the comparison circuit II6 outputs the signal of the logic level "0" because the engine is in the speed increasing state.
In this state, due to the well-known function of the OR circuit 5, the OR circuit 5
Outputs a signal of logic level "1", and the motor 7 operates based on this signal to open the exhaust valve. When the engine speed increases and exceeds the threshold value N, the comparison circuit I4 outputs a signal of logic level "0" and the comparison circuit II6 also outputs a signal of logic level "0". A signal of logic level "0" is output from 5, and the motor 7 is based on this signal.
Operates and the exhaust valve behaves from the open state to the closed state. OR even when the engine speed reaches the point (a) and is then operated at high speed and constant speed until the point (b)
A signal of logic level "0" is output from the circuit 5,
Even when the speed is gradually decelerating from points (B) to (C), the comparator circuit I4 outputs the signal of logic level "0" and the comparator circuit II6 also presets. While the engine deceleration is gentler than the deceleration gradient, the exhaust valve is still in the closed state because the logic level "0" signal is output. By the way, when the throttle is closed during the high speed operation and the speed is rapidly decelerated from the point (c) to the point (d), the points (c) and (d) are larger than the threshold value N, so the comparison circuit I4 The signal of logic level "0" is output, while (c),
If the deceleration gradient between the points (d) is steeper than the deceleration gradient preset in the comparison circuit II6, that is, the deceleration is steep, the comparison circuit II6 outputs a signal of logic level "1". As a result, the OR circuit 5 inputs the signals of the logic levels "0" and "1", and the OR circuit 5 outputs the signal of the logic level "1", whereby the exhaust valve occupies the open state. To do. By opening the exhaust valve during sudden deceleration in this way, the exhaust passage of the engine becomes a low-speed mode, that is, a mode in which blow-through in the exhaust pipe is suppressed. It is possible to prevent it from being sucked out. After the engine decelerates to point (2),
When it is operated at a constant speed such as between points (d) and (e),
Since points (d) and (e) are both larger than the threshold value N, the comparison circuit I4 outputs a signal of logic level "0", while the comparison circuit II6 has a deceleration gradient of 0, so that the logic level "0". Output the signal. Thus, the OR circuit 5 outputs a signal of logic level "0" and the exhaust valve occupies the open state to the closed state again. When the engine speed decelerates slowly from the point (e) and the engine speed becomes smaller than the threshold value N, the comparison circuit II6 outputs a signal of logical level "0" because of the gentle deceleration, but the comparison circuit I4 outputs the signal. A signal of logic level "1" is output and thus the exhaust valve occupies the open state. Briefly describing the operation mode of the exhaust valve in the above engine operating conditions, when the engine speed is lower than the threshold value N, the exhaust valve is open at (I) and (V), the engine speed is higher than the threshold value N, and the speed is rapidly reduced. Without (II) and (IV), the exhaust valve is closed, and when the engine speed is higher than the threshold value N and the vehicle decelerates rapidly (III), the exhaust valve is open.

FIG. 3 shows another embodiment. Engine 10, detector 11, ignition timing controller 12, and magneto 13
The basic control system that controls the operation of the engine by circulating information between the two and controls the motor 15 and the exhaust valve 16 from the detector 11 through the exhaust valve controller 14 remains the same, but the ignition timing controller 12 and the exhaust valve controller 14 are made to input the throttle opening information from the throttle opening detector 17, and the ignition timing controller 12 is made to further input the exhaust valve operation status from the exhaust valve operation detector 18. ing. In this way, by controlling the ignition timing of the engine or the opening / closing operation of the exhaust valve based on a plurality of different information, it becomes possible to perform optimum operation control even in a more complicated engine operating condition.

In this example, a two-cycle engine with an exhaust chamber is taken as an example, but it is of course possible to apply the present invention as a valve operation control system of a two-cycle engine with an intake chamber or an intake / exhaust chamber. Further, although the exhaust valve controller is composed of the / V converter, the differentiating circuit, the comparing circuit and the like in this example, the structure is not limited to the above as long as the object of the present invention can be achieved.

〔The invention's effect〕

As described in detail above, according to the control method for a two-cycle engine according to the present invention, the opening / closing valve for the chamber, which is connected to the intake / exhaust pipe, is used to reduce the engine speed and the decrease rate of the engine speed per unit time. By controlling the opening / closing operation based on the above, it has become possible to efficiently operate the engine corresponding to various driving situations.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between engine speed and elapsed time showing an example of the operating condition of a two-cycle engine operated based on the control method according to the present invention.
FIG. 2 is a block diagram showing a control process in the exhaust valve controller, FIG. 3 is an overall control block diagram of the engine showing another embodiment of the control method according to the present invention, and FIG. FIG. 10 is an overall control block diagram of an engine showing a conventional control method. 1,14 …… Exhaust valve controller, 2 …… / V converter,
3 …… differential circuit, 4,6 …… comparator circuit, 5 …… OR circuit, 7,1
5 ... motor, 10 ... engine, 11 ... detector, 12 ...
Ignition timing controller, 13 Magneto, 16 Exhaust valve, 17 Throttle opening detector, 18 Exhaust valve operation detector.

Claims (1)

[Claims] 1. A method for controlling a two-cycle engine, wherein a chamber is connected to at least one of an intake passage and an exhaust passage via an opening / closing valve, and the opening / closing valve is operated to enhance filling efficiency. If the rotation speed is lower than a preset threshold value, the open / close valve is opened, while if the engine speed is higher than the threshold value, the open / close valve is closed, and the engine speed is higher than the threshold value. A method for controlling a two-cycle engine, characterized in that when the rate of decrease of the engine speed per unit time is larger than a preset rate of decrease, the on-off valve is opened.