JPH0323319A - Control device for internal combustion engine with supercharger - Google Patents

Abstract

PURPOSE:To prevent the generation of noise occasioned by surging by a method wherein, in a device in which a reflux valve is located in an intake air reflux passage for intercommunicating the upper and lower streams of the compressor of a supercharger, control is effected so that the reflux valve is opened during detection of rapid closing of a throttle valve. CONSTITUTION:In an internal combustion engine with a supercharger, through running of a compressor 5 coupled directly to a turbine 4 of a supercharger 3 rotated by means of an exhaust gas, air in an intake air passage 6 is boosted, and supercharging to a combustion chamber 10 is effected through an intercooler 7, a throttle valve 8, and a collector 9. An intake air passage part 6 between the intercooler 7 and the throttle valve 8 is connected to the intake air passage part on the upper stream side of the compressor 5 through a reflux passage 14, and a reflux valve 15 is located in the middle thereof. In this case, control is effected so that when, based on output signals from a throttle sensor 31 and a number of revolutions sensor 33, rapid closing of the throttle valve 8 is detected by a control unit 32, the reflux valve 15 is opened.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a control device for a supercharged internal combustion engine, and particularly relates to opening/closing control of a recirculation valve provided in an intake recirculation passage connecting upstream and downstream of a compressor. ．． <Prior art> In a supercharged internal combustion engine, when the throttle valve is suddenly operated in the closing direction, such as during deceleration, supercharging occurs due to the inertia of the supercharger even though the throttle valve is closed. As the compressor of the aircraft continues to perform supercharging, the pressure downstream of the compressor increases, and furthermore, separation occurs from the blades around the blade row of the compressor, causing a phenomenon in which fluid flows backward from downstream of the compressor to upstream of the compressor, so-called surging. A phenomenon occurs. Therefore, conventionally, as shown in Japanese Unexamined Patent Publication No. 62-78430 and Japanese Utility Model Application No. 63-46628, a slot is installed downstream of the compressor to recirculate the supercharged intake air downstream of the compressor to the upstream side of the compressor. A reflux passage is provided that connects the upstream part of the torque valve and the upstream part of the compressor, and the reflux passage is further provided with a reflux valve that opens and closes communication between the passages. Here, the recirculation valve is actuated by a diaphragm, and the pressure from the intake passage downstream of the throttle valve and the pressure near the recirculation valve located upstream of the throttle valve are introduced into the diaphragm, and the pressure introduced into the diaphragm is When the difference exceeded a predetermined value, the recirculation valve was opened to allow the supercharged air downstream of the compressor to flow back upstream of the compressor, lowering the pressure and preventing the occurrence of surging. <Problems to be Solved by the Invention> However, in the conventional configuration, the opening/closing control of the reflux valve is performed by introducing the pressure upstream and downstream of the throttle valve into the diaphragm, and when the pressure difference introduced into the diaphragm exceeds a predetermined value. The valve opening was controlled by sliding, which caused the following problems. That is, to explain with reference to FIG. 4, when the throttle valve is suddenly closed (throttle valve closed), the pressure (Pu) upstream of the throttle valve introduced into the diaphragm and the pressure (Pd) downstream of the throttle valve are It takes time for the differential pressure (δP) above a predetermined value to occur, and before the reflux valve takes effect, surging (S) of the supercharger occurs during deceleration, which causes abnormal noise (R). do. In addition, when a pressure difference between the upstream and downstream sides of the throttle valve exceeds a predetermined value, the recirculation valve is opened and the supercharged intake air downstream of the compressor is recirculated upstream of the compressor through the recirculation passage. In the so-called half-throttle state where the throttle valve is slightly opened, the above-mentioned recirculation valve does not need to act, but the downstream side of the throttle valve has a very low negative pressure, so the differential pressure is always above a predetermined value. There were problems such as the recirculation valve opening and insufficient intake air being supplied to the internal combustion engine, resulting in a decrease in engine torque. The present invention has been made in view of the above circumstances, and provides a control device for a supercharged internal combustion engine that can quickly and reliably prevent the occurrence of surging by operating a recirculation valve without using differential pressure. The purpose is to Means for Solving the Problems> For this reason, the present invention provides a compressor of a supercharger in an intake passage of an internal combustion engine, and a recirculation passage downstream of the compressor that connects an upstream part of the throttle valve and an upstream part of the compressor. In a supercharged internal combustion engine, the recirculation valve is provided in a recirculation passage and opens and closes communication between the recirculation passage, and the recirculation valve includes at least an electromagnetic solenoid, and the opening degree of the throttle valve The system is equipped with a detection means that includes a throttle sensor that detects sudden closing of the throttle valve, and a control means that opens the recirculation valve when the detection means detects the sudden closing of the throttle valve. <Operation> According to this control device for a supercharged internal combustion engine, the opening of the throttle valve is detected by the throttle sensor, and when sudden closing of the throttle valve is detected from the rate of change in the opening of the throttle valve, etc., the recirculation passage is opened. Since the opening and closing of the reflux valve, which opens and closes the communication between the two valves, is controlled, the opening and closing operations of the reflux valve are performed quickly and reliably in approximately synchronization with the operation of the throttle valve. <Example> Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 1 showing a first embodiment of the present invention, exhaust gas discharged from an internal combustion engine main body I passes through an exhaust passage 2 and rotates a turbine 4 of a supercharger 3. As shown in FIG. A compressor 5 is provided coaxially with the turbine 4, and the compressor 5 rotates in synchronization with the turbine 4 to supercharge the air in the intake passage 6. The supercharged air passes through the intercooler 7, the throttle valve 8, and the collector 9 on the intake passage 6, and is then mixed with fuel injected from the injector 11 just before the combustion chamber IO of the internal combustion engine main body l, and flows into the combustion chamber 10. is supplied to. Note that an air cleaner 12 is provided upstream of the intake passage.

Further, a reflux passage 14 is provided between the intercooler 7 and the throttle valve 8 and opens upstream of the compressor 5, and is opened and closed by a reflux valve 15 provided in the reflux passage 14. Here, the reflux valve l5 is opened and closed by a diaphragm l6, and includes a pressure operation chamber 18 into which pressure is introduced through a pressure introduction path l7, and the diaphragm l6.
When the three-way electromagnetic valve 20 is turned off, the positive pressure Pu upstream of the throttle valve 8 passes through the positive pressure introduction path 22 and the pressure introduction path 17. is introduced into the pressure working chamber 18 to close the communication of the recirculation passage 14, while the three-way solenoid valve 20 is
By setting the pressure to N, the negative pressure Pd in the vacuum tank 2l, which is in communication with the collector 9 and is always maintained substantially constant by a one-way valve (not shown), is transferred through the negative pressure introduction path 23 and the pressure introduction path 17. is introduced to open the communication of the reflux passage 14. Further, as a structure according to the present invention, a throttle sensor 3l for detecting the opening TVO of the throttle valve 8 is provided, and the opening TVO is controlled by a control unit 32, which will be described later.
The rate of change ΔTVO is also detected. Further, a rotation speed sensor 33 for detecting the engine rotation speed N is provided, and these detection signals are inputted to a control unit 32 containing a built-in microcomputer, which controls the three-way solenoid valve 20 according to the flowchart described later to control the recirculation. The passage 14 is opened and closed. That is, the control unit 32 corresponds to a detection means for detecting sudden closing of the throttle valve 8, and a control means for opening the recirculation valve 15 when the detection means detects the sudden closing of the throttle valve 8. Next, the recirculation valve 15 is controlled through switching control of the three-way solenoid valve 20 executed by the control unit 32 in the control device for a supercharged internal combustion engine configured as described above.
The opening/closing control will be explained according to the flowchart shown in FIG. Note that this flowchart is executed at predetermined intervals.

In step (denoted as S in the figure; the same applies hereinafter) (2), the opening degree TVO of the throttle valve 8 detected by the throttle sensor 3l is read and input. In step 2, the engine rotation speed N detected by the rotation speed sensor 33 is input.

In step 3, it is determined whether the input opening degree TVO of the throttle valve 8 is equal to or greater than a predetermined opening degree C. Predetermined opening degree C
In the above case, since the throttle valve 8 is opened by a predetermined opening degree or more, it is assumed that the state is not a so-called half-throttle state, and the process proceeds to step 4.

On the other hand, when the opening degree TVO is less than the predetermined opening degree C, it is considered to be a half-throttle state, so as described later, the process proceeds to step 13, where the three-way solenoid valve 20 is turned off and the recirculation valve 15 is closed.

In step 4, the opening degree TVO and the opening degree TvO of the throttle valve 8 when the routine was executed last time are determined.
By calculating the difference from
= T V O T V O o t D). Furthermore, after calculating the rate of change ΔTVO, TVO is
Save as vOOLD. Whether or not the engine l is in a state of rapid deceleration depends on the operating state of the engine l. In step 5, the engine speed N and the opening degree TV of the throttle valve 8 are determined.
Using a three-dimensional map from O, a predetermined value ωl of the rate of change in opening used to judge sudden deceleration is determined. That is, the predetermined value ω1 is a negative value. Then, in step 6, the step 4
Whether the rate of change ΔTVO of the opening obtained in Step 5 is smaller than the predetermined negative value ω1 obtained in step 5, the change in the opening TVO of the so-called throttle valve 8 is a more rapid change in the closing direction. Determine whether or not. If it is smaller than the predetermined value ωl, it is assumed that there is a sudden deceleration, and the process proceeds to step 7, where the three-way solenoid valve 20 is turned on and the recirculation valve I5 is opened.

On the other hand, if the opening change rate ΔTVO is not smaller than the predetermined value ωl, the engine l is at least not rapidly decelerating, so there is no need to turn on the three-way solenoid valve 20 and open the recirculation valve l5, and step l3 Proceed to reflux valve 15
Let be closed.

Then, the process proceeds to step 8, where the opening degree TVO of the throttle valve 8 detected by the throttle sensor 31 after the three-way solenoid valve 20 is turned on is read, and manual operation is performed again. In step 9, the difference between the opening TvO read in step 8 and TvOoLD, which is the opening TVO of the throttle valve 8 when the routine was executed last time, is determined to determine the opening after the three-way solenoid valve 20 is turned ON. rate of change in degree (for example, angular velocity of opening degree) ΔTVO (=TVO TVOo
to ). Furthermore, as in step 4 above, after calculating the rate of change ΔTVO, TVO is stored as TVOOLI1. Similar to the determination in the case of sudden deceleration in step 5.6, whether or not the engine 1 is in a state of acceleration depends on the state in which the engine 1 is being operated, and in step 10, the engine speed is determined. Using a three-dimensional map from N and the opening TVO of the throttle valve 8, a predetermined value ω2 of the rate of change in the opening used for determining acceleration is determined. still,
The predetermined value ω2 is a value of 0 or more.

Then, in step 11, it is determined whether the opening change rate ΔTVO obtained in step 9 is larger than the positive predetermined value ω2 obtained in step 10, and whether the so-called engine 1 is accelerating at a predetermined rate or higher. Decide whether or not. and a predetermined value ω2
If it is larger, the engine 1 is assumed to be in an accelerating state, and the process proceeds to step 13, where the three-way solenoid valve 20 is turned off and the recirculation valve l5 is closed in order to supply the entire amount of intake air supercharged by the compressor 5 to the combustion chamber 10. This closes the connection of the reflux passage l4. On the other hand, in step 1l, if the opening change rate ΔTVO is not larger than the predetermined value ω2, it can be determined that the engine 1 continues to be in a deceleration state, so the three-way solenoid valve 20 remains ON. Turn on 20
By opening the recirculation valve 15, a part of the supercharged intake air is not supplied to the combustion chamber IO.
It is common for the output of engine 1 to decrease. Therefore, in step 12, the elapsed time t from turning on the three-way solenoid valve 20 in step 7 is set to a predetermined time t0.
By comparing with
S) Proceed to step 13, turn off the three-way solenoid valve 20, close the recirculation valve 15 to supply the entire amount of supercharged intake air to the combustion chamber IO, and start recirculation! Close 14 contacts. Note that the elapsed time t is the predetermined time t. If not, return to step 8 and judge again whether engine 1 is accelerating at a predetermined rate or higher. As explained above, according to this embodiment, it is determined whether or not the half throttle state is reached by comparing the opening degree TVO of the throttle valve 8 with the predetermined opening degree C. In the half-throttle state where it is not necessary to circulate the supplied intake air, the recirculation valve 15 is closed and sufficient intake air can be supplied to the combustion chamber 10 of the engine body 1. Furthermore, in this embodiment, the opening degree TVO of the throttle valve 8,
The opening and closing of the recirculation valve 15, which opens and closes the connection of the recirculation passage 14, is controlled according to the operating state of the engine, using the opening change rate ΔTVO and the engine speed N. Here, the reflux valve 15 is opened and closed by a diaphragm l6, and the positive pressure Pu upstream of the throttle valve B and the negative pressure Pd in the vacuum tank 21 are connected to the pressure through the three-way solenoid valve 20 and the pressure introduction path 17. Since there is almost no time delay in introducing the flow into the working chamber 18, as a result, the opening/closing operation of the recirculation valve 15 is approximately the same as the ON/OFF operation of the three-way solenoid valve 20.
This can be done in conjunction with the operation of the throttle valve 8. As a result, there is almost no response delay, and the response is performed quickly and reliably. Therefore, it is possible to reliably prevent the generation of abnormal noise due to surging that occurs when the throttle valve 8 is suddenly operated in the closing direction, such as during deceleration, as shown by the dotted line in Fig. 4. Become.

What is shown in FIG. 3 shows a second embodiment of the present invention. Note that the same structural elements as in the first embodiment are given the same reference numerals as in FIG. 1, and the explanation thereof will be omitted.

In this embodiment, communication between the recirculation passage 14 is opened and closed by a solenoid valve 25 provided in the recirculation passage 14.Here, as in the first embodiment, the throttle valve 8 is opened and closed.
t T V O etc. are input to the control unit 32, and the solenoid valve 25 is turned off to close the communication of the recirculation passage 14, and the solenoid valve 25 is turned on.
By doing so, we will open contact. The switching control of the electromagnetic valve 25 is the same as the flowchart shown in FIG. 2, so the explanation thereof will be omitted. Therefore, in this embodiment as well, the opening/closing operation of the electromagnetic valve 25 is performed in conjunction with the operation of the throttle valve 8, so that there is almost no response delay and the recirculation passage can be quickly and reliably opened.
Since the opening/closing of the communication 4 is controlled, it is possible to reliably prevent the occurrence of abnormal noise due to surging that occurs when the throttle valve 8 is suddenly operated in the closing direction, such as during deceleration. ．． <Effects of the Invention> As explained above, according to the present invention, sudden closing of the throttle valve is detected based on the opening degree of the throttle valve, the rate of change in opening degree, and the engine speed, and the sudden closing of the throttle valve is detected. Since the reflux valve installed in the reflux passage is opened at certain times, the connection between the reflux passage and This can be reliably prevented through reliable opening control, and there is no reduction in engine torque since opening control is not performed when communication of the recirculation passage is not required, such as in a half-throttle state.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram showing a first embodiment of the present invention, FIG. 2 is a flow chart showing a control routine of the same embodiment, and FIG. 3 is a system configuration diagram showing a second embodiment of the present invention.
FIG. 4 is a diagram illustrating problems in the conventional example and the effects of the embodiment.

Claims (1)

[Scope of Claims] A compressor of a supercharger is provided in an intake passage of an internal combustion engine, and a recirculation passage downstream of the compressor connects an upstream part of a throttle valve and an upstream part of the compressor, and a recirculation passage provided in the recirculation passage to communicate the passage. In a supercharged internal combustion engine comprising a recirculation valve that opens and closes, the recirculation valve includes at least an electromagnetic solenoid, and a throttle sensor that detects the opening degree of the throttle valve. 1. A control device for a supercharged internal combustion engine, comprising: a detection means for detecting a sudden closing of a throttle valve; and a control means for opening the recirculation valve when the detection means detects a sudden closing of a throttle valve.