JPH05195837A - Surge controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the wear of an air flow meter and maintain engine brake effective nesswith simple structure. CONSTITUTION:In the case where an idle switch is turned on (S200), if a counter CTS indicates 0 (S210), opening degree thetat for surge is taken as target throttle opening degree thetax(S230), and when the counter CST indicates 1/2 of reference cycle KCTS (S240), target throttle opening degree thetax is switched to zero (S260), and when the counter CTS indicates reference cycle KTCS (S270), the counter CTS indicates zero (S230)taking opening degree thetat for surge as target opening degree thetax again (S230).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surge control device for preventing pulsation of intake air in an internal combustion engine with a supercharger.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 11 (A), in an internal combustion engine (engine) A1 of an automobile or the like, a compressor A2 is rotated by an exhaust turbine in order to improve the performance of the engine A1. There is a supercharger (turbocharger) A3 that performs the intake of the above is installed in the intake path A4.

The engine A1 equipped with this supercharger A3 is
When the throttle valve A5 is closed during the deceleration operation, the compressor A2 continues to rotate at high speed for a short time due to the inertial force up to that time, and as shown in FIG.
The downstream pressure Pm ₂ suddenly rises and is reflected, resulting in both the upstream and downstream pressures Pm ₁ and Pm _{2 of the} supercharger A3 causing hunting. Due to the intake pulsation (turbo surge) between the upstream and downstream of the supercharger A3, the movable part A7 of the air flow meter A6 located upstream of the supercharger A3 flaps and the movable part A7 moves.
7 was the cause of wear. In addition, it has hindered accurate measurement of the intake air amount.

The following techniques have been proposed as measures against this turbo surge. Pulsation is provided by providing a bypass passage between the upstream and downstream of the turbocharger and an intake control valve in the bypass passage, which is opened during deceleration operation to allow the pressure on the downstream side of the turbocharger to escape to the upstream side. There is a technique to prevent
-277820 and JP-A-63-38622).

When the surge occurs, the throttle valve and the bypass valve of the throttle valve are opened,
There is a technique for preventing pulsation by releasing the pressure on the downstream side of the supercharger to the engine side (Japanese Patent Laid-Open No. 62-9164).
No. 1 and JP-A No. 62-91642).

[0006]

However, such a technique has the following problems and is not always suitable. That is, in the above technique, a bypass passage and an intake control valve must be newly provided, and the number of parts and the number of manufacturing steps are increased, which is not preferable. Further, there is a problem that pulsation is easily transmitted to the upstream side.

Further, in the above-mentioned technique, since the throttle valve and the bypass valve are opened, another problem that the effect of engine braking is deteriorated occurs. The present invention has been made to solve the above problems, and an object of the present invention is to provide a surge control device for an internal combustion engine, which prevents wear of an air flow meter, has a simple structure, and does not impair the effectiveness of engine braking.

[0008]

The present invention for achieving the above object is, as illustrated in FIG. 1, a supercharger M for supplying compressed air to the engine body side to an intake passage M2 of an internal combustion engine M1.
In the surge control device for an internal combustion engine, which is provided with 3 and which suppresses the pulsation of intake air in the intake passage M2, an opening / closing means M4 provided downstream of the supercharger M3 for opening and closing the intake passage M2, Full closing instruction means M5 for instructing full closing of the opening / closing means M4, and when a full closing instruction is given from the full closing instruction means M5, the opening / closing means M4 is drive-controlled to control the intake passage M2. A gist is a surge control device for an internal combustion engine, which is provided with an opening / closing control means M6 that periodically opens and closes.

[0009]

In the surge control device for an internal combustion engine of the present invention having the above-mentioned structure, compressed air is supplied to the engine body side by the supercharger M3 provided in the intake passage M2 of the internal combustion engine M1. The intake passage M2 is opened / closed by an opening / closing means M4 such as an electronically controlled linkless throttle or a sub-throttle valve provided on the downstream side of the intake passage M2.

When an instruction to fully close the intake passage M2 is issued from the fully closing instruction means M5 such as a pedal sensor or an idle switch, the opening / closing control means M6 drives and controls the opening / closing means M4. The intake passage M2 is periodically opened / closed so as to be opened / closed by, for example, a rectangular or wavy signal.

Thus, for example, when the accelerator is returned, the intake passage M2 is periodically opened and closed without being fully closed, so that the effect of engine braking is not reduced and the occurrence of intake pulsation is prevented. To be done.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a surge control device for an internal combustion engine of the present invention will be described below with reference to the drawings. FIG. 1 shows the entire system of the control device of this embodiment. As shown in FIG. 2, the intake manifold 3 is arranged on the upstream side of the intake air of the engine 1, and the exhaust manifold 5 is arranged on the downstream side.

From the upstream side of the intake manifold 3, an air flow meter 7 for detecting the amount of intake air, a supercharger (turbocharger) 9 for increasing the density of intake air, and an intake passage (by electronic control) are opened and closed. A linkless throttle valve 11 is disposed, and a step motor 13 that drives the throttle valve 11 and a throttle position sensor 15 that detects the opening degree of the throttle valve 11 are attached to the throttle valve 11.

The engine 1 main body is provided with a fuel injection valve 17 for injecting fuel for each cylinder, a rotation speed sensor 19 for detecting the engine rotation speed Ne, and the like. The exhaust manifold 5 is provided with an exhaust side turbine 9a of the supercharger 9 and a bypass passage 21 of the exhaust side turbine 9a. In the bypass passage 21, a waste gate valve 23 for adjusting the supercharging pressure is provided. It is provided. Therefore, when the exhaust side turbine 9a is rotated by the exhaust gas from the engine 1, the supercharger 9 is driven and the intake side turbine 9b is rotated, and the intake air is compressed and supplied to the engine 1 main body side.

Further, the accelerator pedal 25 has an accelerator sensor 26 for detecting the depression amount of the accelerator pedal 25.
In addition, an idle switch 27 that is turned on when the accelerator pedal 25 is released is provided. The entire system of the engine 1 includes an electronic control circuit (ECU) 3
This ECU 31 is controlled by the CPU 1, a well-known CPU 31a, a ROM 31b, and a RAM 31 as shown in FIG.
c, bus line 31d, input unit 31e and output unit 31f
Etc.

The input unit 31e of the ECU 31 has
Air flow meter 7, throttle position sensor 15,
A rotation speed sensor 19, an accelerator sensor 26, an idle switch 27, etc. are connected, and their signals are transmitted to the ECU 3
Input to 1. On the other hand, the output unit 31f includes a step motor 13, a fuel injection valve 17, and a waste gate valve 23.
Etc. are connected, and a control signal for controlling the engine speed Ne, opening / closing control of the throttle valve 11 described later, and the like is output from the ECU 31.

Next, the control of this embodiment performed by the ECU 31 will be described with reference to FIGS. 4 to 9. Of these, FIG. 4 is a timing chart of this control, FIGS. 5 and 8 are flowcharts of this control, and FIGS. 6, 7, and 9 are graphs showing the relationship between this control and the engine speed Ne.

First, referring to FIGS. 4 and 5, the overall control performed according to the depression state of the accelerator pedal 25 will be described. This process is performed every 10 ms. As shown in both figures, step (hereinafter step is referred to as S) 100
Then, based on the signal from the accelerator sensor 26, the accelerator operation change amount dAp is obtained by subtracting the previous accelerator operation amount Ap from the current accelerator operation amount Ap.

In subsequent S110, the accelerator operation change amount d
It is determined whether Ap is greater than or equal to a predetermined value kdAp,
That is, it is determined whether or not the amount of change is a rapid deceleration, and if an affirmative determination is made here, the process proceeds to S120, and if a negative determination is made, the process proceeds to S140. In S120, the counter CSURG that ends the period for performing the control for suppressing the intake pulsation (surge control period) of the present embodiment is set to 0, and the flag XSURG that indicates the execution of the control for suppressing the pulsation (surge control) is turned on. And

In subsequent S130, the periodic opening / closing control of the throttle valve 11 and the setting of the throttle opening θt for surge prevention, which will be described later in detail in the process of the subroutine of FIG. 8, are performed, and the present process is terminated. On the other hand, the above S11
In step S140, which is answered in the negative with 0, the flag XSU
It is determined whether or not RG is on, that is, whether or not surge control has already been performed, and if an affirmative determination is made here, S15
On the other hand, if the determination is negative, the process proceeds to S180.

In S150, the counter CSURG is set in advance for a predetermined period set value KCSURG (see FIG. 4).
It is determined whether or not the above is true, that is, the surge control may be performed for a certain period after the rapid deceleration, so it is determined whether or not the preset surge control period has been exceeded. Here, if an affirmative decision is made that the surge control period has ended, then the processing advances to S160, whereas if a negative decision is made that the surge control period has not ended, S17.
Go to 0.

It should be noted that the state of pulsation is determined by the engine speed N
Since it varies depending on e, the period setting value KCSURG is
As shown in FIG. 6, it is set to increase as the engine speed Ne increases. In S170, the counter CSURG is incremented, and the above S130 is performed again.
Go to and perform surge control.

On the other hand, in S160, the flag XSURG indicating surge control is turned off at the end of the surge control period, and the process proceeds to S180. In S180, normal throttle opening setting control is performed. That is, as shown in FIG. 7, when the surge control is not performed, the target throttle opening θx is set according to the engine speed Ne and the opening of the accelerator pedal 25 based on the map stored in the ROM 31b.
Is performed, and the present process is terminated.

Next, the surge control subroutine executed in S130 will be described with reference to FIG. 8 and FIG. As shown in both figures, it is determined whether or not the idle switch 27 is on, that is, whether or not the accelerator pedal 25 is released and an instruction to fully open the intake passage is given,
If an affirmative judgment is made here, the routine proceeds to S210, while if a negative judgment is made, the routine proceeds to S220.

In S210, it is determined whether or not the counter CTS for setting the cycle is 0, that is, whether or not the idle switch 27 is turned on for the first time this time. If a positive determination is made here, the process proceeds to S230, On the other hand, if a negative decision is made, the operation proceeds to S240. In S230, the preset throttle valve opening for surge control (surge opening) θt
Is set as the target opening (target throttle opening) θx of the throttle valve 11. This is because a sudden deceleration is determined (at S110 in FIG. 5) and the idle switch 25 is turned on for the first time this time, so it is determined that all conditions for performing surge control are satisfied, and the throttle for surge control is determined. The setting processing of the opening degree θ is performed.

It should be noted that the state of pulsation is determined by the engine speed N
Since it varies with e, the surge opening θt is set to increase as the engine speed Ne increases, as shown in FIG. In the following S250, the counter C
The TS is incremented and this process is once terminated.

A negative determination is made at S210 and the process proceeds to S2.
At 40, the counter CTS has a preset reference period K.
It is determined whether it is equal to 1/2 of CTS (see FIG. 4) or above or below. That is, the surge control of this embodiment is
Since the throttle opening θ is periodically switched to suppress the pulsation, the processing in S240 is performed in the reference cycle KCT.
This is for changing the throttle opening θ every ½ of S.

At S240, 1 / of the reference period KCTS
When it is determined that the value is less than 2, that is, the reference cycle KCTS
When it is determined that the surge opening degree θt is not reached, the process returns to S230 and the surge opening θt is maintained. Further, when it is determined that it is equal to 1/2 of the reference cycle KCTS, that is, when it is determined that the time to switch the throttle opening θ has been reached, the target throttle opening θx is switched to 0 in S260, and the above-mentioned is performed again. It returns to S250 and continues counting. Furthermore,
If it is determined that it exceeds 1/2 of the reference period KCTS, that is, if it is determined that 1/2 of the reference period KCTS has already passed, the process proceeds to S270.

At S270, it is determined whether the counter CTS is equal to or longer than the reference period KCTS. This processing is also the above-mentioned S24.
This is for changing the throttle opening θ for each reference cycle KCTS, which is almost the same as the processing for 0. This S270
If the affirmative determination is made that the reference period KCTS or more, it means that the reference period KCTS has already been reached.
At 0, the counter CTS is set to 0, and the process proceeds to S250 to perform counting again. On the other hand, here, the reference cycle KCTS
If it is determined that the throttle opening degree θ has not been reached, it means that the time to switch the throttle opening θ has not yet been reached.
Returning to 60, the target throttle opening θx is maintained at 0.

That is, the above S230, S240, S26
The processing from 0 to S280 is 1 / of the reference cycle KCTS.
It is a process of switching the throttle opening θ to the surge opening θt and the fully closed state for each two. In S220, which is judged negative in S200, the conditions for surge control are not all satisfied, so the counter CTS is set to 0 and the process returns to S250.

The configuration and control processing of this embodiment as described above have the following effects. In this embodiment, rapid deceleration is detected based on the signal from the accelerator sensor 26, and based on the signal from the idle switch 27,
It is detected that the throttle valve 11 is in the fully closed idle state, and surge control is executed when these conditions are satisfied. In this surge control, control is performed to periodically switch the throttle opening degree θ between a fixed amount (surge opening degree θt) between a valve open state and a fully closed state. Therefore, even if the accelerator pedal 11 is loosened and the supercharger 19 operates by inertia, it is possible to effectively suppress the pulsation of intake air caused by the operation.

That is, as shown in FIG. 10, since the throttle opening θ is periodically switched, the remarkable effect that the pulsation of intake air can be suppressed not only on the downstream side of the supercharger 19 but also on the upstream side thereof. .. Further, in this surge control, the throttle opening θ is not fully opened but is opened periodically, that is, only slightly, so that the effect of the engine braking is not deteriorated, and the throttle valve 11 Since the opening and closing can be realized only by controlling the drive of the conventional step motor 13, there is an advantage that the device configuration can be extremely simple.

It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be carried out in various modes without departing from the gist of the present invention. For example,
In the above-described embodiment, the throttle valve 11 is opened and closed in a pulsed manner by repeatedly opening and closing the valve for a fixed period / a fixed amount and then fully closing it for a fixed period. Of course, it is possible to draw various curves such as waves.

[0034]

As described above, in the surge control device for an internal combustion engine according to the present invention, when the instruction to fully close the intake passage is given from the fully closing instruction means, the opening / closing control means drives and controls the opening / closing means. Since the intake passage is opened and closed periodically, for example, when the accelerator is returned, the occurrence of intake pulsation is effectively prevented without reducing the effectiveness of engine braking. As a result, wear of the movable part of the air flow meter is reduced, and moreover, the measurement of the intake air amount becomes more accurate. Further, there is an advantage that the device configuration is simple.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram illustrating a configuration of the present invention.

FIG. 2 is an explanatory diagram showing an entire system of an engine control device according to the present embodiment.

FIG. 3 is a block diagram showing an electronic control circuit.

FIG. 4 is a timing chart showing surge control of this embodiment.

FIG. 5 is a flowchart showing the overall control of throttle opening.

FIG. 6 is a graph showing a relationship between a surge period set value and an engine speed.

FIG. 7 is a graph showing a relationship between a target throttle opening degree, an engine speed, and an accelerator pedal operation amount.

FIG. 8 is a flowchart showing surge control.

FIG. 9 is a graph showing the relationship between surge throttle opening and engine speed.

FIG. 10 is a graph showing the effect on pulsation of this example.

FIG. 11 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

1 ... Engine, 3 ... Intake manifold, 7 ... Air flow meter, 9 ... Supercharger (turbocharger), 11 ... Throttle valve,
13 ... Step motor 15 ... Throttle position sensor, 19 ... Rotation speed sensor, 25 ... Accelerator pedal, 26 ... Accelerator sensor, 27 ... Idle switch, 31 ...
Electronic control circuit (ECU)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsunori Takao 1-1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd.

Claims (1)

[Claims] 1. A surge control device for an internal combustion engine, comprising a supercharger for supplying compressed air to an engine body side in an intake passage of an internal combustion engine, and suppressing a pulsation of intake air in the intake passage. An opening / closing means provided downstream of the opening / closing means for opening / closing the intake passage, a full-closing instruction means for instructing the full closing of the opening / closing means, and a full closing instruction from the full closing instruction means. A surge control device for an internal combustion engine, comprising: an opening / closing control unit that drives the opening / closing unit to periodically open / close the intake passage.