JPH09177590A - Method for determining excessive state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately determine an excessive state so as to always control an ignition time to an optimal ignition time by setting a threshold value based on a detected air intake pipe pressure and a revolution number and determining the excessive state of an engine running state based on this threshold value and a detected air intake pipe pressure. SOLUTION: A control part 6 inputs a rotational signal outputted from a rotation sensor 9, a pressure signal outputted from a pressure sensor 8, a water temperature signal outputted from a water temperature sensor 30 and the like to an input interface 6c. By an excessiveness determination program, the air intake pressure of an engine EG and an engine revolution number are first detected and a threshold value is set by retrieving a two-dimensional table based on these. Then, the excessive running state of the engine EG is detected based on the threshold value and the detected air intake pressure. Thus, the mistaken determination of an excessive state caused by the influence of pulsation is prevented and normal control is performed for an ignition time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transient judging method for judging that a vehicle is in a transient state such as during acceleration, mainly in an internal combustion engine for automobiles.

[0002]

2. Description of the Related Art Conventionally, in a carburetor type engine,
For example, as disclosed in Japanese Unexamined Patent Publication No. 56-126647, there is known one that determines a steady state or a transient state based on a signal output from an O ₂ sensor attached to an exhaust system. Further, in a fuel injection type engine, the steady state and the transient state are judged from the intake pipe pressure within a fixed time, that is, the amount of change in the intake pressure, for each engine speed, and the amount of fuel injected and the ignition timing are controlled. Is going. Specifically, a threshold value for determining the amount of change in intake pressure with respect to the engine speed is set, and when it exceeds the threshold value, it is determined to be a transient state, and when it is below, it is determined to be a steady state. judge.

[0003]

By the way, in the case of applying to the carburetor system such a type which determines the transient state from the variation of the intake pressure, the carburetor system is introduced as it is because of the difference in the structure of the intake system. Difficult to do. That is, in a fuel injection type engine, a surge tank having a relatively large volume is generally provided in the intake system,
In the carburetor type, the intake manifold is generally used as short as possible so that the air-fuel mixture reaches each cylinder evenly. As a result, it is difficult to provide a large volume space such as a surge tank at a position downstream of the throttle valve.

As described above, when there is no space such as a surge tank downstream from the throttle valve, the amount of change in intake pressure can change greatly even in a steady state due to the influence of intake pulsation generated in the intake system. is there. For this reason, depending on how the threshold value is set, it is determined to be a transient state because the amount of change exceeds the threshold value even if it is a steady state, or conversely, it is determined to be a steady state even if it is a transient state. Sometimes. That is, if the threshold value is set with reference to the steady state in consideration of the influence of intake pulsation, stable engine rotation can be obtained in the original steady state, but as shown in FIG. 3, the throttle valve is fully opened to accelerate ( There is a case where it is erroneously determined to be a steady state even though it is in a transient state (WOT acceleration), and an appropriate acceleration state cannot be obtained, that is, acceleration is slow and traveling may be slow. On the contrary, when the threshold value is set based on the transient state, the acceleration state is improved, but as shown in FIG. 4, the transient state and the steady state are repeatedly determined in the steady state. By changing each time of the judgment,
Rough idle or drive surge due to torque fluctuation may occur.

[0005] An object of the present invention is to solve such a problem.

[0006]

In order to achieve the above object, the present invention takes the following measures. That is, the transient determination method according to the present invention is a transient determination method for determining the transient state of the internal combustion engine in order to control at least the ignition timing of the internal combustion engine, and detects the intake pipe pressure and the rotational speed of the internal combustion engine. Then, a threshold value is set based on the detected intake pipe pressure and the rotational speed, and it is determined that the operating state of the internal combustion engine is in the transient state based on the set threshold value and the detected change in the intake pipe pressure. Characterize.

With such a configuration, the threshold value is set based on the intake pipe pressure and the number of revolutions, so that the threshold value reflects the operating state of the internal combustion engine at that time. That is, when the threshold value is set only by the rotation speed of the internal combustion engine, even if the rotation speed is the same, since the intake pulsation is different due to the difference in the throttle opening, the transient state may be erroneously determined. By setting the threshold value based on the rotation speed and the intake pipe pressure, it is possible to reflect the difference in intake pulsation due to the difference in throttle opening degree in the threshold value.

As a result, a carburetor type internal combustion engine,
Even if the volume of the internal surge tank of the fuel injection type internal combustion engine is relatively small, the transient state can be determined without being affected by the intake pulsation. Therefore, based on this determination result, even if the ignition timing is changed,
Since the transient state is accurately determined, the optimum ignition timing can be set and good combustion can be obtained. For this reason, it is possible to prevent the drive surge that occurs as a result of changing the ignition timing by changing the ignition timing even in the steady state, and eliminate the problems such as rough idle and poor acceleration. be able to.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention, for example, in an internal combustion engine equipped with a carburetor, detects the intake pipe pressure downstream of the throttle valve and also detects the rotational speed, and based on the detected intake pipe pressure and rotational speed. Then, the threshold value defined in the two-dimensional table is searched and set, and if the change in the intake pipe pressure at that time is equal to or more than the set threshold value, it is determined to be in the transient state.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, an engine EG for an automobile is shown.
Is equipped with the carburetor 1 and the pressure sensor 8 in the intake system 3, and the exhaust manifold 41 of the exhaust system 4 is installed.
A catalyst 42 is attached to the. The pressure sensor 8 is the intake system 3
It is provided downstream of the throttle valve 24 in order to detect the intake pipe pressure, that is, the intake pressure PM.

The carburetor 1 is formed by integrally forming a carburetor body 1a and a body portion 1b which constitutes a part of the intake system 3. The carburetor body 1a has a float chamber 11 for temporarily storing fuel, a main well 12 communicating with the float chamber 11, and a fuel stored in the main well 12 communicating with the main jet 14 formed in the body portion 1b. A main nozzle 15 leading to a small venturi 22, a slow fuel passage 16 forming a slow system, and an idle adjust screw 19 for changing the opening area of the idle port 18 to adjust the fuel amount during idle operation. The throttle port 24 is provided on the upstream side of the idle port 18, and the throttle port 24 is closed in a fully closed state during idle operation. In the carburetor 1 having such a configuration, the main system is composed of the main well 12, the main jet 14, and the main nozzle 15, and the slow system is the slow fuel passage 16, the idle port 18, the idle adjust screw 19, and the slow throttle system. And port 20.

The body portion 1b has an air chamber 21 to which air from an air filter (not shown) reaches, a small venturi 22 provided in the air chamber 21, a large venturi 23 provided downstream thereof, and a downstream of the large venturi 23. And a throttle valve 24 that is rotatably provided. The throttle valve 24 rotates in conjunction with an accelerator pedal (not shown), and a control unit 6 described later.
The opening / closing is electrically controlled by an actuator 7 operated by a negative pressure supplied from a VSV (vacuum switching valve) 5 whose opening degree is controlled by. Such an idle-up mechanism including the VSV 5 and the actuator 7 also serves as an existing so-called D-range idle-up mechanism that is provided for performing the D-range idle-up when the automatic transmission is installed, for example. Good.

The control unit 6 includes a central processing unit 6a which constitutes a microcomputer system, a storage unit 6b which stores programs and data, an input interface 6c which outputs each signal inputted from the outside to the central processing unit 6a, An A / D converter 6e that converts an input analog signal into a digital signal, an output interface 6d that outputs a signal output from the central processing unit 6a to each control element, and an igniter IGN that outputs an ignition signal to the spark plug SP are provided. Configured to have. The input interface 6c of the control unit 6 has an engine E
Rotation sensor 9 for detecting the engine speed NE of G
The rotation signal Ne output from the pressure sensor 8, the pressure signal Pm output from the pressure sensor 8, the water temperature signal Stw output from the water temperature sensor 30, and the like are input. On the other hand, from the output interface 6d, a drive signal for rotating a drive motor of a radiator fan for supplying cooling air to a radiator (not shown) for cooling the cooling water and a VSV5 for operating an actuator for idle up are provided. A control signal or the like for controlling is output.

The control unit 6 has a built-in program for determining a transient state. Further, a program for controlling the ignition timing based on the result of this transient determination program is also incorporated. Regarding the control of the ignition timing, it is possible to apply what is known in the art,
Description is omitted. This transient determination program detects the intake pressure PM of the engine EG and the engine speed NE, sets a threshold FCSTA based on the detected intake pressure PM and engine speed NE, and sets the set threshold FCSTA and the detected intake pressure NE. It is configured to determine that the operating state of the engine is in a transient state based on the change in PM.
Further, the storage device 6b stores a threshold FCS in a two-dimensional table defined by the intake pressure PM and the engine speed NE.
TA candidates are stored. That is, the intake pressure PM, specifically, the signal output from the pressure sensor 8 is A / D converted by the A / D converter 6e into a raw intake pressure value PMAD and the engine speed NE to define one threshold FCSTA candidate. I am doing it. This two-dimensional table is searched, four points are interpolated from the detected intake pressure PM and the number of revolutions, and the threshold FCSTA at that time is set. The threshold value FCSTA has a larger value as the engine speed NE is smaller and the raw intake pressure value PMAD is larger. Therefore, at the same engine speed NE, the value increases as the intake pressure value PMAD increases, and at the same raw intake pressure value PMAD, the value increases as the engine speed NE decreases.

The transient judgment program is as follows, for a predetermined time, for example, 5 msec. It is executed every time. FIG.
First, in step S1, the transient flag XPMT
Reset (= 0) P. In step S2, it is determined whether or not the transient flag XPMTP has been reset. In step S3, the raw intake pressure value PMAD for determining the intake pressure value PMTP2 for controlling the ignition timing is set.
Two values that have been tampered with, that is, two times smoothed value PMADN2
Then, the smoothed value PMADN16 is subtracted 16 times, and it is determined whether or not the absolute value AVPMN is greater than or equal to the threshold value FCSTA.
In this step S3, the gently changing 16-time average value PMADN16 and the relatively rapidly changing twice smoothed value PAD
The magnitude of change in intake pressure PM is detected based on the difference from MADN2. In other words, 16 times smoothed value PMAD
Even if the intake pressure PM greatly changes in the transient state, N16 does not change greatly following the change. On the other hand, the twice-annealed value PMADN2 greatly changes reflecting the change in the intake pressure PM in the transient state. By detecting the difference between the two, the magnitude of change in the actual intake pressure PM is detected.

In step S4, the intake pressure value PMTP2 is set to the twice smoothed value PMADN2, and the transient flag XPM is set.
Set (= 1) TP. In step S5, the intake pressure PM twice-annealed value PMADN2 to 16-time averaged value P
MADN16 is subtracted, and it is determined whether or not the absolute value AVPMN is greater than or equal to the determination value α. This determination value α is used to determine a transient state from the magnitude of the change in the intake pressure PM regardless of the engine speed NE and the intake pressure PM, and in this embodiment, a compatible value (fixed value) is applied. . Note that the determination value α may be a variable value set based on, for example, the engine speed NE and the intake pressure PM, like the threshold value FCSTA. In step S6, the intake pressure value PMT P2 is determined to be the rounded value PMADN16 16 times,
Reset the transient flag XPMTP. The two-time smoothed value PMADN2 and the sixteen-time smoothed value PMADN16 may be calculated by the following formulas. PMADN2 = PMADN2 _n-1 + (PMAD-PM
ADN2 _n-1 ) / 2 PMADN16 = PMADN16 _n-1 + (PMAD-
PMADN16 _n-1 ) / 16 In such a configuration, for example, in an idle operation state or a steady state in which the accelerator pedal is in a substantially constant state, the intake pressure PM does not change, so the control is performed in steps S1 → S2 → S3. → Proceeds to S6, determines the intake pressure value PMTP2 to be the rounded value PMADN16 16 times, and sets the transient flag X
Reset PMTP. In this steady state, the control is
After this, steps S2 → S3 → S6 are repeatedly executed,
Unless the magnitude of change in the intake pressure PM, that is, the absolute value AVPMN exceeds the threshold value FCSTA, the transitional state is not determined. The threshold value FCSTA is set based on the engine speed NE and the intake pressure PM, and is designed to reflect the operating state at that time. For example, the threshold value FCSTA becomes a large value in an idle operating state where the engine speed NE is low. Because
If a relatively large change in intake pressure PM does not occur, the transient state is not determined, and the transient state can be accurately determined. Therefore, in the steady state,
The engine speed NE fluctuates by determining that it is transient in response to a slight change in the intake pressure PM, and repeating the steady state and the transient state to frequently control the ignition timing to the optimum ignition timing. Can be prevented.

When the accelerator pedal is depressed to accelerate the vehicle in the steady state as described above, the opening degree of the throttle valve 24 becomes larger than that in the idle state or before the accelerator pedal is depressed, so that the intake valve is closed. The atmospheric pressure PM changes greatly. In this case, the control proceeds from the steady state to step S2 → S3, and the absolute value AVPMN becomes
If it is greater than or equal to the threshold value FCSTA set based on the engine speed NE and the raw intake pressure value PMAD at this time, it is determined to be in a transient state, and the routine proceeds to step S4, where the intake pressure value PMTP2
Is determined as the rounded value PMADN2 twice, and the transient flag XP is set.
Set MTP. Therefore, the ignition timing is set to the determined intake pressure value PMTP2 which is the two-time smoothed value PMADN2.
Is controlled by After that, if the acceleration state continues and the absolute value AVPMN becomes equal to or larger than the determination value α, the control proceeds to steps S2 → S5 → S4 because the transition flag XPMTP is set, and the transition is made. Judge as a state. That is, when the state in which the change in the intake pressure PM is equal to or larger than the determination value α which is the predetermined value continues, it is determined to be the transient state. As described above, when the transient state is determined from the steady state, the transient state can be accurately determined according to the operating state because the threshold value FCSTA that changes in value depending on the engine speed NE and the intake pressure PM is used. it can.

When the acceleration state ends and the vehicle decelerates and the absolute value AVPMN falls below the judgment value α, the control proceeds to steps S2 → S5 → S6, which is judged to be a steady state, and the intake pressure value PMTP16 is an average of 16 times PM
ADN16 is determined and the transient flag XPMTP is reset. Once the steady state is determined, the transient flag XPM
Since TP has been reset, control is performed in step S2.
→ Proceeds to S3, and then proceeds to step S6 until the absolute value AVPMN becomes equal to or more than the threshold value FCSTA, determines the steady state, and controls the ignition timing. After that, when the deceleration further progresses and the absolute value AVPMN becomes equal to or more than the threshold value FCSTA, the control proceeds to steps S2 → S3 → S4, and it is determined again that the state is the transient state.

In this way, when the transient state is judged when the steady state is transited to the transient state, the absolute value AVP is used.
Since MN is compared with the threshold value FCSTA for determination, the determination is made according to the operating state at that time, that is, the engine speed NE and the intake pressure PM, and the accuracy can be improved. Therefore, it is possible to prevent the transient state from being erroneously determined due to the influence of the pulsation, and it is possible to suppress rough idle, drive surge, and the like in order to perform normal ignition timing control. Further, since the transient state can be accurately determined, the transient state is erroneously determined as the steady state and the ignition timing is not advanced,
It is possible to prevent problems such as slow acceleration.

The present invention is not limited to the embodiment described above. Although the engine EG equipped with the carburetor has been described in the above embodiment, for example, in a fuel injection type engine including a fuel injection valve, a surge tank provided downstream of the throttle valve has a relatively small volume. It may be applied. In this case, the intake pressure value PMTP2 in the above embodiment may be used for both ignition timing control and fuel injection control. In such a small-volume surge tank, since intake pulsation may occur as in the case of the carburetor, as described above, the intake pressure is set at a threshold value set based on the engine speed NE and the intake pressure PM. By determining the magnitude of PM, it is possible to accurately determine the transient state without being affected by the intake pulsation.

In addition, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0023]

As described above, according to the present invention, the transient state can be accurately determined even if the intake pulsation exists in the intake system at that time. Therefore, even when the ignition timing is controlled at least based on the determination result, the ignition timing can always be controlled to the optimum ignition timing, and as a result, a good combustion state can be divided into a steady state and a transient state. It can be maintained in both. Therefore, it is possible to prevent rough idle, drive surge, and the like, and prevent acceleration failure.

[Brief description of the drawings]

FIG. 1 is a schematic configuration explanatory view showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure of the embodiment.

FIG. 3 is an operation explanatory view of a conventional example.

FIG. 4 is an operation explanatory view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Carburetor 6 ... Control part 6a ... Central processing unit 6b ... Storage device 6c ... Input interface 6d ... Output interface 8 ... Pressure sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location F02M 19/00 F02M 19/00 Z F02P 5/15 F02P 5/15 B (72) Inventor Kazumoto Hashimoto Remains 1-1, Taoyuan, Ikeda, Osaka Prefecture Daihatsu Industry Co., Ltd. (72) Inventor, Shoji Miyatake 2-1-1 Taoyuan, Ikeda City, Osaka Prefecture Daihatsu Industry Co., Ltd.

Claims (1)

[Claims] 1. A transient determination method for determining a transient state of an internal combustion engine for controlling at least an ignition timing of the internal combustion engine, comprising: detecting an intake pipe pressure and a rotational speed of the internal combustion engine; A transient determination method characterized in that a threshold value is set based on the pressure and the number of revolutions, and the operating state of the internal combustion engine is determined based on the set threshold value and the detected change in the intake pipe pressure. .