JPH11324775A - Intake and exhaust valve control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake and exhaust valve control system that is capable of preventing any abnormal combustion including not only knocking but self- ignition and preignition as well in an internal combustion engine. SOLUTION: Upon a determination that an engine 201 is in a rapid acceleration state by an acceleration determination means 208, it is determined whether the conditions on which abnormal combustion occurs are met or not from detection values about the intake pressure, engine temperature, engine speed and air-fuel ratio. If the occurrence conditions are found fulfilled, a variable intake/ exhaust valve opening/closing timing mechanism 207 controls or retards the closing of the intake valves. The timing at which intake compression starts is thus delayed to lower the cylinder pressure or to prevent any unintended ignition phenomenon. When the detection value of an engine speed detection means 204 thereafter indicates that the engine speed exceeds a prescribed value that avoids any abnormal combustion, the closing of the intake valves are returned or advanced to the original state before the rapid acceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to control of an internal combustion engine for avoiding abnormal combustion.

[0002]

2. Description of the Related Art FIG. 2 shows a configuration of an anti-knock control as an example of a conventional method of controlling an internal combustion engine corresponding to abnormal combustion. This is composed of an ignition type internal combustion engine 101, an opening degree detection means 102 of an intake air flow control valve, a knock detection means 103, a crank angle detection means 104, a calculation means 105, and an ignition timing control means 106. When the opening degree detecting means 102 of the intake flow rate adjusting valve detects the sudden acceleration of the internal combustion engine 101, the calculating means 105 detects the crank angle by the crank angle detecting means 104 and issues a command to the ignition timing control means 106 to set the ignition timing. Knocking is prevented by retarding. Thereafter, the ignition timing is advanced gradually, and the knock detection means 1
If the knock is detected, the ignition timing is retarded again. If the knock is not generated, the ignition timing is advanced to the ignition timing before the rapid acceleration.

[0003]

In the above prior art, when abnormal combustion such as self-ignition and preignition occurs in addition to knocking, the air-fuel mixture self-ignites without external ignition. In addition, even if the ignition timing was retarded, no abnormal combustion prevention effect was obtained at all. In Japanese Patent Application Laid-Open No. 4-246249, a valve timing control mechanism is provided to prevent the occurrence of knocking, and control is performed so that the valve overlap between the intake valve and the exhaust valve is minimized in a low rotation and high load region. Although there is a point slightly similar to the present invention in that knocking is prevented by controlling the valve timing, there is a case where abnormal combustion occurs in an operation region other than the low rotation high load region. Not considered at all.

[0004]

According to the first aspect of the present invention, when it is determined that abnormal combustion occurs immediately after the start of acceleration, when the signal is input to the accelerator, the intake valve is simultaneously opened. Since the closing angle is retarded and the filling efficiency is reduced,
The in-cylinder pressure is reduced, and abnormal combustion can be prevented. If the closing angle of the intake valve is at the most retarded position and cannot be further retarded, the control of the closing angle of the intake valve to the target advanced position is performed as in the invention of claim 2. By prohibiting and maintaining the current state, it is possible to wait for the abnormal combustion state to end.

According to the third aspect of the present invention, in the case of an internal combustion engine provided with a non-cut power transmission device, if the abnormal combustion occurs at the time when the operation of the stop device is terminated, the intake valve is closed. By retarding the angle, the same effect as in claim 1 can be obtained with better responsiveness.

According to the fourth aspect of the present invention, if the abnormal combustion occurs in the same state as the second aspect, the idle speed of the engine is increased to increase the idle speed.
The effect in the case of claim 2 can be enhanced.

[0007]

FIG. 1 shows the configuration of a control system according to a first embodiment of the present invention. In this example, the internal combustion engine 201, the intake pressure detecting means 202, the engine temperature detecting means 20
3. It is constituted by a rotational speed detecting means 204, an air-fuel ratio detecting means 205, a calculating means 206, an intake valve opening / closing timing variable mechanism 207, and an acceleration determining means 208.

FIG. 3 is a flowchart illustrating a control procedure of the control system according to the first embodiment of the present invention. If it is determined in step 301 that the engine (or the vehicle) is in a state of rapid acceleration, an interrupt is issued and step 30 is executed.
In step 2, it is determined from the detection values of the intake pressure, the engine temperature, the number of revolutions, and the air-fuel ratio whether the abnormal combustion occurs. If the condition for occurrence of abnormal combustion is not satisfied, nothing is performed, but if it is determined that the condition for occurrence of abnormal combustion is satisfied, step 3 is executed.
Proceeding to 03, retard control of the closing angle of the intake valve is performed. At this time, as shown in FIG. 4, when a judgment signal 401 from the acceleration judgment means 208 is input, the lift amount of the intake valve changes from the conventional lift amount 402a to the special lift amount 402b by this control, and the width 404 Only the closing angle of the intake valve is retarded. As a result, the in-cylinder pressure waveform assuming that the start of compression is delayed and ignition is not performed at the same intake pressure is the difference 40 from the conventional pressure waveform 403a to the pressure waveform 403b of the present control result.
It drops by five.

That is, by reducing the in-cylinder pressure by this control, an unintended ignition phenomenon can be prevented, and a normal combustion state can be obtained. Thereafter, the intake pressure detecting means 202, the engine temperature detecting means 203, the rotational speed detecting means 2
04, monitoring the information from the air-fuel ratio detecting means 205, interrupts at step 304 when the engine speed exceeds a predetermined value at which abnormal combustion can be avoided, and determines the closing angle of the intake valve at step 305. Return to the state before rapid acceleration (advance).

FIG. 5 shows a configuration of a control system according to a second embodiment of the present invention. In the case of the second embodiment, a stop device 508 capable of outputting an operation signal is used instead of the acceleration determining means 208 in the case of the first embodiment. Here, the stop device is a device such as a brake having a function of stopping a running vehicle.

FIG. 6 is a flowchart illustrating a control procedure according to a second embodiment of the present invention. Basic operation is first
This is the same as that of the embodiment, except that the interrupt condition in step 601 is determined depending on whether or not the stopping device is released. The effect when the retard control of the intake valve is performed is the same as that of the first embodiment. However, by executing the control of the intake valve closing angle by the release signal of the stop device as in step 601, the intake valve is controlled. Can be executed earlier.

FIG. 7 shows a configuration of a control system according to a third embodiment of the present invention. In the case of the third embodiment, the internal combustion engine 70
1, intake pressure detecting means 702, engine temperature detecting means 703,
Revolution speed detection means 704, air-fuel ratio detection means 705, main intake control valve opening degree detection means 706, calculation means 707, operation detection means 708 of a stop device, intake valve opening / closing timing variable mechanism 709
It consists of. The difference from the second embodiment lies in that an opening degree detecting means 706 for the main intake adjustment valve is provided.

FIG. 8 is a flowchart illustrating a control procedure according to a third embodiment of the present invention. First, as in the case of the second embodiment, an interrupt is issued in step 801 when the stop device is released. At this time, step 80
In 2, it is determined from the intake pressure, the engine temperature, the number of revolutions, and the air-fuel ratio whether or not a condition for causing abnormal combustion is satisfied. If the generation condition is not satisfied, nothing is performed. When it is determined that the condition for occurrence of abnormal combustion is satisfied, the routine proceeds to step 803, in which the closing angle of the intake valve is retarded. Further, immediately at step 804, the idle speed is increased. Thereafter, when the main intake control valve is opened, the signal of the opening degree detecting means 706 is received and an interrupt is entered in step 805, and in step 806, the set value of the idle speed is returned (reduced). Also, information from the intake pressure detecting means 702, the engine temperature detecting means 703, the rotational speed detecting means 704, and the air-fuel ratio detecting means 705 are monitored, and the rotational speed of the engine exceeds a predetermined value at which abnormal combustion can be avoided. At step 807, an interruption is made, and at step 808, the closing angle of the intake valve is returned to the state before the rapid acceleration. According to the control method of the third embodiment, in addition to the effect of the second embodiment, there is an effect that higher abnormal combustion prevention performance can be obtained by increasing the engine idle speed.

FIG. 9 shows a procedure of a control operation different from the flowchart shown in FIG. 3 to be applied to the special case of the first embodiment described above. In the control procedure shown in FIG. 3, when it is determined that the condition for occurrence of abnormal combustion is satisfied in the rapid acceleration state, the retard control of the closing angle of the intake valve is performed in step 303. The retard control of the angle is possible when the vehicle is accelerating from a constant speed driving state or when the vehicle is suddenly accelerating from a gentle acceleration state. In the state of vehicle speed 0 as if it is operating, the intake valve closing angle is usually at the most retarded position, so when suddenly accelerating from that state,
The closing angle of the intake valve cannot be further retarded.

Therefore, in such a special case of the first embodiment, a special control procedure as shown in the flowchart of FIG. 9 can be used. That is, vehicle speed 0
When it is determined that the condition for occurrence of abnormal combustion is satisfied in the rapid acceleration from step 302, steps 302 to 30 following step 301 in the flowchart of FIG.
Proceed to 6 to prohibit the target advance control of the intake valve. As a result, an increase in the in-cylinder pressure is suppressed to prevent an unintended ignition phenomenon, thereby leading to a normal combustion state. If the engine speed exceeds the predetermined value in step 304 while such an operation state continues, the process proceeds to step 307, in which the prohibition of the target advance control of the intake valve is released, and the target advance control is performed. Resume. If the condition for occurrence of abnormal combustion is not satisfied in step 302, the process proceeds to step 308,
The target advance control of the intake valve is executed as usual.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a configuration of a control system according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a configuration of a conventional control system.

FIG. 3 is a flowchart illustrating a control operation procedure of the control system according to the first embodiment.

FIG. 4 is a time chart showing the operation and effect of the first embodiment.

FIG. 5 is a conceptual diagram illustrating a configuration of a control system according to a second embodiment of the present invention.

FIG. 6 is a flowchart illustrating a control operation procedure of the control system according to the second embodiment.

FIG. 7 is a conceptual diagram illustrating a configuration of a control system according to a third embodiment of the present invention.

FIG. 8 is a flowchart illustrating a control operation procedure of the control system according to the third embodiment.

FIG. 9 is a flowchart showing a control operation procedure of the control system in a special case of the first embodiment, which is different from that of FIG. 3;

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiko Watanabe 14 Iwatani, Shimowakakucho, Nishio City, Aichi Prefecture Inside the Japan Automobile Parts Research Institute (72) Inventor Yasuyuki Kawabe 14 Iwatani, Shimowakakucho, Nishio City, Aichi Prefecture Stock Company (72) Inventor Yoshiaki Ito 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (4)

[Claims] An internal combustion engine having an intake valve opening / closing timing variable mechanism includes an acceleration determination unit, an intake pressure detection unit, an engine temperature detection unit, a rotation speed detection unit, and an air-fuel ratio detection unit, and the engine is in an accelerated state. When it is determined that there is a condition, it is determined from the detection values of the respective detection means whether or not the condition for generating abnormal combustion is satisfied, and it is determined that the condition for generating abnormal combustion is satisfied. An intake / exhaust valve control device, wherein an abnormal combustion is prevented by retarding an intake valve closing angle in such a case. 2. The method according to claim 1, wherein when it is determined that abnormal combustion is established, when the intake valve closing angle cannot be further retarded, the intake valve closing angle is shifted to a target advanced position. An intake / exhaust valve control device, wherein control is prohibited. 3. An internal combustion engine having an intake valve opening / closing timing variable mechanism, comprising a stop device operation detection unit, an intake pressure detection unit, an intake temperature detection unit, a rotation speed detection unit, and an air-fuel ratio detection unit. At the moment when the combustion is canceled, it is determined whether or not abnormal combustion occurs from the detection values of the respective detecting means. If it is determined that the condition for causing abnormal combustion is satisfied, the intake valve closing angle is retarded. By squaring,
An intake and exhaust valve control device for preventing occurrence of abnormal combustion. 4. An internal combustion engine having an intake valve opening / closing timing variable mechanism, comprising a stop device operation detection unit, an intake pressure detection unit, an intake temperature detection unit, a rotation speed detection unit, and an air-fuel ratio detection unit. At the moment when the condition is released, it is determined from the detection values of the respective detecting means whether or not a condition for causing abnormal combustion is satisfied. An intake / exhaust valve control device characterized in that occurrence of abnormal combustion is prevented by retarding a valve closing angle and further increasing an idle speed.