JP2004332613A - Air bypass valve control device for internal combustion engine with supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air bypass valve control device for an internal combustion engine with a supercharger, for controlling an air bypass valve provided therein to properly handle a waist gate valve driving mechanism, when malfunctioned. <P>SOLUTION: The internal combustion engine with the supercharger has the supercharger 10 consisting of a turbine arranged in an exhaust passage and a compressor arranged in an intake passage, the waist gate valve 21 mounted in a bypass line 20 for bypassing the turbine of the supercharger in the exhaust passage, and the waist gate valve driving mechanism 23 for driving the waist gate valve 21. The air bypass valve control device for the internal combustion engine with the supercharger comprises an air bypass valve mechanism 31 for communicating/shutting off an air bypass line 30 bypassing the compressor of the supercharger 10 in the intake passage and a control means 50 for controlling the air bypass valve mechanism 31. When determining that the waist gate valve driving mechanism 23 is malfunctioned, the control means 50 controls the air bypass valve mechanism 31 to put the air bypass line 30 into a communicated condition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air bypass valve control device for a supercharged internal combustion engine.
[0002]
[Prior art]
In an internal combustion engine with a supercharger, there has been proposed an example in which a supercharging pressure sensor is provided in an intake passage, and the opening degree of a wastegate is feedback-controlled based on a supercharging pressure measured by the supercharging pressure sensor (for example, see Patent Reference 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-345851
Patent Literature 1 discloses that when a supercharging pressure sensor is determined to be faulty, supercharging pressure control is performed by follow-up control that does not use a measured supercharging pressure.
[0005]
[Problems to be solved by the invention]
However, it does not disclose how to deal with an abnormality in the drive mechanism of the wastegate.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide an air bypass valve, and when an abnormality occurs in a wastegate valve driving mechanism, control the air bypass valve to appropriately cope with the problem. The present invention provides an air bypass valve control device for an internal combustion engine with a supercharger.
[0007]
Means for Solving the Problems and Functions and Effects
In order to achieve the above object, the invention according to claim 1 of the present invention bypasses a turbocharger including a turbine disposed in an exhaust passage and a compressor disposed in an intake passage, and a turbine of the supercharger in the exhaust passage. In an internal combustion engine with a supercharger having a wastegate valve interposed in a bypass passage and a wastegate valve driving mechanism for driving the wastegate valve, an air bypass bypassing a compressor of the supercharger in an intake passage An air bypass valve mechanism for communicating and blocking the passage, and control means for controlling the air bypass valve mechanism, wherein the control means, when it is determined that the wastegate valve drive mechanism is abnormal, the air bypass passage An air bypass valve for a supercharged internal combustion engine that controls the air bypass valve mechanism so as to enable communication. And a control device.
[0008]
When an abnormality occurs in the wastegate valve driving mechanism, the air bypass passage is made communicable, and the air bypass passage is communicated with a supercharging pressure equal to or higher than a predetermined pressure so that the pressure is controlled to a predetermined pressure or less. It is possible to reduce surge noise such as the above, and prevent disconnection of the intake system piping and overshoot of the supercharging pressure.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment according to the present invention will be described below with reference to FIGS.
FIG. 1 is a schematic configuration diagram of an internal combustion engine with a supercharger and a wastegate valve control device according to the present embodiment.
[0010]
In the internal combustion engine 1, an intake passage 4 for intake and an exhaust passage 5 for exhaust extend from a combustion chamber in a cylinder 2 in which a piston 3 reciprocates, and a turbine 11 provided in the exhaust passage 5 The compressor 12 provided in the intake passage 4 is integrated with the turbocharger 10.
[0011]
An air cleaner 6 is provided at an end of the intake passage 4 upstream of the compressor 12, and an intercooler 7 and a throttle valve 8 are sequentially provided downstream of the compressor 12.
[0012]
An exhaust bypass passage 20 is provided in the exhaust passage 5 to bypass the turbine 11 of the supercharger 10 and communicate between the upstream side and the downstream side of the turbine 11. A waste gate valve 21 is interposed in the exhaust bypass passage 20, The gate valve 21 opens and closes the exhaust bypass passage 20.
[0013]
The waste gate valve 21 is opened and closed by the diaphragm actuator 24 in communication with the pressure chamber 24b of the diaphragm actuator 24.
The diaphragm chamber 24a of the diaphragm type actuator 24 communicates with the intake passage 4 upstream of the compressor 12 via the pressure guiding passage 25.
[0014]
A waste gate solenoid valve 26 is interposed in the middle of the pressure guiding passage 25, and the waste gate solenoid valve 26 is driven to open and close by a waste gate solenoid 27.
[0015]
In the pressure guiding passage 25, a branch passage 25a is branched downstream of the waste gate solenoid valve 26 and communicates with the intake passage 4 downstream of the compressor 12, and an orifice 28 is formed in the branch passage 25a.
[0016]
As described above, the wastegate valve driving mechanism 23 is configured by the diaphragm type actuator 24 and the wastegate solenoid 27 and the like.
[0017]
The waste gate valve driving mechanism 23 is configured such that the waste gate solenoid valve 26 opens the pressure guiding passage 25 by energizing the waste gate solenoid 27, and introduces the intake pressure into the diaphragm chamber 24a of the diaphragm type actuator 24, and increases the pressure in the pressure chamber 24b. The wastegate valve 21 closes the exhaust bypass passage 20.
[0018]
When the power supply to the waste gate solenoid 27 is cut off, the pressure in the diaphragm chamber 24a of the diaphragm type actuator 24 is released, and the pressure in the pressure chamber 24b is reduced, so that the waste gate valve 21 opens the exhaust bypass passage 20.
[0019]
The energization of the wastegate solenoid 27 is performed by a pulse drive signal whose duty ratio is controlled, and the opening of the wastegate by the wastegate valve 21 is controlled by the duty ratio. Supercharging is promoted by flowing toward the turbine 11.
[0020]
Therefore, when the power supply to the wastegate solenoid 27 is turned off and the wastegate valve 21 fully opens the exhaust bypass passage 20, almost all of the exhaust gas flows through the exhaust bypass passage 20, and the supercharging pressure by the supercharger 10 is smaller than a predetermined pressure. Can be suppressed.
[0021]
The intake passage 4 is provided with an air bypass passage 30 that bypasses the compressor 12 and connects the downstream side of the intercooler 7 and the upstream side of the compressor 12, and a relief valve 32 is interposed in the air bypass passage 30. Have been.
[0022]
The relief valve 32 is a diaphragm-type valve. The inside of a valve body 32a is divided into a diaphragm chamber 32d and a communication chamber 32e by a diaphragm 32c to which a valve body 32b is attached, and the opening and closing of the air bypass passage 30 by movement of the valve body 32b. Is going.
The valve element 32b is urged in the closing direction by a spring 32f.
[0023]
When the pressure in the communication chamber 32e becomes higher than the pressure in the diaphragm chamber 32d by a predetermined pressure or more, the valve body 32b opens to communicate with the air bypass passage 30, and recirculates the supercharging pressure on the downstream side of the compressor 12 to the upstream side. To relieve.
[0024]
The diaphragm chamber 32d communicates with an output port 35c of an air bypass valve 35, which is a three-port solenoid valve. An input port 35b of the air bypass valve 35 communicates with the downstream side of the throttle valve 8, and another input port 35a. Communicates with the upstream side of the throttle valve 8.
[0025]
The air bypass valve mechanism 31 is configured as described above. When the input port 35b is closed and the input port 35a is opened in the demagnetized state of the air bypass solenoid 36, the intake negative pressure on the downstream side of the throttle valve 8 is output. It acts on the diaphragm chamber 32d of the relief valve 32 via the port 35c, so that the relief valve 32 can be opened.
[0026]
When the air bypass solenoid 36 is excited, the input port 35a is closed and the input port 35b is opened, so that the intake pressure on the upstream side of the throttle valve 8 acts on the diaphragm chamber 32d of the relief valve 32 via the output port 35c. With the same pressure as the communication chamber 32e, the relief valve 32 is kept closed by the urging force of the spring 32.
[0027]
Therefore, when the power supply to the air bypass solenoid 36 is turned off, the relief valve 32 is opened, and when the supercharging pressure of the supercharger 10 becomes higher than a predetermined pressure, the relief valve 32 is opened to open the air bypass passage. 30 communicates and the pressure is reduced.
[0028]
Various controls of the internal combustion engine 1 are performed by an ECU (Electronic Control Unit) 50. The ECU 50 provides signals from various sensors indicating the operating state of the internal combustion engine 1, for example, the engine speed Ne and the throttle opening Th. , The intake negative pressure Pb, the atmospheric pressure Pa, the intake temperature T, and the like are input and processed to perform various controls. The control of the wastegate valve driving mechanism 23 and the control of the air bypass solenoid 36 of the air bypass valve mechanism 31 are also performed. This is performed by the ECU 50.
[0029]
In the internal combustion engine 1 with the supercharger described above, the ECU 50 determines whether the wastegate valve driving mechanism 23 is abnormal and controls the air bypass valve mechanism 31 according to the abnormality based on the flowcharts of FIGS. 2 and 3. Will be explained.
[0030]
FIG. 2 shows a procedure for determining an abnormality of the wastegate valve driving mechanism 23. First, it is determined whether the IG1 voltage applied to the wastegate solenoid 27 that drives the wastegate solenoid valve 26 is equal to or lower than a predetermined voltage. Then, if the voltage is equal to or lower than the predetermined voltage, the abnormality determination is not performed, and the process jumps to step 5 to initialize the abnormal state timer (set and start the timer) and initialize the normal state timer (step 6).
[0031]
If the IG1 voltage exceeds the predetermined voltage, the process proceeds to step 2 to determine whether or not the duty ratio of the output to the wastegate solenoid 27 is equal to or more than a predetermined duty ratio (for example, 90%). It is determined whether the output duty ratio is equal to or less than a predetermined duty ratio (for example, 10%). If the duty ratio is excessively large or small, the abnormality is unstable and cannot be accurately detected. No judgment is made.
[0032]
Further, in the next step 4, it is determined whether or not the battery voltage is equal to or higher than a predetermined voltage. Even if the battery voltage is lower than the predetermined voltage, accurate abnormality determination cannot be performed.
[0033]
If it is determined in step 4 that the battery voltage is equal to or higher than the predetermined voltage, the process proceeds to step 7 where a wastegate solenoid signal is detected (returned) to determine whether a duty signal is present.
[0034]
If the duty signal is present, the wastegate solenoid signal is normal, the process proceeds to step 8, the abnormal state timer is initialized, and it is determined whether the normal state has passed a predetermined time by the normal state timer (step 9), and the predetermined time is determined. When the time elapses, the process proceeds to step 10 to determine the normal state, and sets the abnormal flag Fw = 0.
[0035]
If the wastegate solenoid signal is detected (returned) in step 7 and it is determined that the duty signal does not exist, it is not normal, and the process jumps to step 11 to determine whether or not the abnormal state has passed for a predetermined time by the abnormal state timer. Then, when a predetermined time has elapsed, the process proceeds to step 12 to determine the abnormal state, and sets “1” to the abnormal flag Fw.
Then, the normal state timer is initialized (step 13).
[0036]
As described above, the abnormality of the wastegate valve driving mechanism 23 is determined from the wastegate solenoid signal, and the air bypass valve mechanism 31 is controlled based on the abnormality flag Fw that is the result of the determination.
The control procedure of the air bypass valve mechanism 31 will be described with reference to the flowchart shown in FIG.
[0037]
First, in step 21, data of the throttle opening Th indicating the operating state of the internal combustion engine 1, the intake negative pressure Pb, and the like and the abnormal flag Fw are input.
In the next step 22, it is determined whether or not "1" is set in the abnormality flag Fw. If it is determined that "1" is set and the wastegate valve driving mechanism 23 is abnormal, the process jumps to step 33. The power supply to the air bypass solenoid 36 is turned off.
[0038]
When the power supply to the air bypass solenoid 36 is turned off, the air bypass valve 35 closes the input port 35b and opens the input port 35a, so that the intake negative pressure downstream of the throttle valve 8 is reduced via the output port 35c to the relief valve 32. The relief valve 32 is brought into a valve openable state (a state in which the supercharging pressure is relieved at a predetermined pressure or higher).
[0039]
Therefore, when an abnormality occurs in the wastegate valve driving mechanism 23, even if the supercharging by the supercharger 10 rises without being controlled by the wastegate, the relief valve 32 is in a valve openable state. When the pressure is equal to or higher than the predetermined pressure, the relief valve 32 is opened, the air bypass passage 30 is communicated, and the supercharging pressure is reduced.
[0040]
As described above, when the waste gate valve driving mechanism 23 has an abnormality, the air bypass valve mechanism 31 suppresses the supercharging pressure to a predetermined pressure or less. In addition, it is possible to prevent an overshoot of the supercharging pressure.
[0041]
If it is determined in step 22 that there is no wastegate solenoid signal abnormality (Fw = 0), the process proceeds to step 23, where it is determined whether or not a fixed time has elapsed since the start of the internal combustion engine 1, and the fixed time has elapsed. If it is not possible to ensure stable driving of the internal combustion engine 1, the process jumps to step 34 to turn on the power supply to the air bypass solenoid 36, keeps the relief valve 32 closed, and stops the supercharging by the supercharger 10. It can be done without suppression.
[0042]
If it is determined in step 23 that a certain period of time has elapsed after the start of the internal combustion engine 1 and stable driving has been started, the process proceeds to step 24, where it is determined whether or not energization of the air bypass solenoid 36 is off. Proceed to step 25, but if not in the off state (on state), jump to step 27.
[0043]
Since it is in the ON state at the beginning after the engine is started, the routine jumps to step 27 to search for the intake negative pressure Pon for controlling the energization of the air bypass solenoid 36 based on the engine speed Ne.
The upper limit intake negative pressure Pon for controlling the energization on the engine speed Ne is determined in advance and prepared as a map.
[0044]
Then, in the next step 28, the searched upper limit intake negative pressure Pon to be controlled to be energized is compared with the current intake negative pressure Pb previously input, and if it is less than the upper limit intake negative pressure Pon, the routine jumps to step 34. The energization of the air bypass solenoid 36 is controlled to be ON, and the supercharging is continued.
[0045]
In step 31, it is determined whether or not the negative pressure fluctuation ΔPb of the intake negative pressure Pb per one rotation of the internal combustion engine is equal to or more than a predetermined value ΔP. If less than the predetermined value ΔP, the process jumps to step 34 to energize the air bypass solenoid 36. Is turned on to continue the supercharging. If the negative pressure fluctuation ΔPb is large and is equal to or more than the predetermined value ΔP, the routine proceeds to step 32, the ABV off timer is initialized, and the energization to the air bypass solenoid 36 is turned off (step 33). The relief valve 32 is brought into a valve openable state, that is, a state in which the supercharging pressure can be released.
[0046]
If it is determined in step 24 that the energization of the air bypass solenoid 36 is off, the process proceeds to step 25, where it is determined whether or not the throttle opening Th exceeds a predetermined opening Th1, and the predetermined opening Th1 is determined. If it exceeds, the routine jumps to step 34 to turn on the energization of the air bypass solenoid 36 so that the supercharging pressure can be supercharged without being relieved.
[0047]
If the throttle opening Th is equal to or less than the predetermined opening Th1 in step 25, the process proceeds to step 26, where it is determined whether or not the ABV off timer has counted a predetermined time, and the process skips to step 33 until the predetermined time has elapsed. To continue the off state of energization of the air bypass solenoid 36, and when a predetermined time elapses, the routine proceeds to step 29, where the intake negative pressure for controlling the energization of the air bypass solenoid 36 to be off from a map prepared in advance based on the engine speed Ne. Search for Poff.
[0048]
Then, in the next step 30, the upper limit intake negative pressure Poff for conducting power-off control searched as described above is compared with the current intake negative pressure Pb. The energization of the solenoid 36 is controlled from off to on to perform supercharging without relief of the supercharging pressure.
[0049]
Even if the intake negative pressure Pb is equal to or higher than the upper limit intake negative pressure Poff, the process proceeds to step 31 to determine whether the negative pressure variation ΔPb is equal to or higher than the predetermined value ΔP. To turn on the power supply to the air bypass solenoid 36.
[0050]
If the negative pressure fluctuation ΔPb is large and equal to or greater than the predetermined value ΔP, the process proceeds to step 32, where the ABV off timer is initialized (the timer is set and started), and the off state of energization to the air bypass solenoid 36 is maintained (step 33), maintaining a state in which the supercharging pressure can be relieved.
[0051]
The air bypass valve mechanism 31 is controlled as described above.
As described above, when “1” is set in the abnormality flag Fw in step 22 after the data is input to indicate the abnormality of the wastegate valve driving mechanism 23, the air bypass valve mechanism 31 directly jumps to step 33 to perform the air bypass solenoid operation. The power supply to 36 is turned off, and the supercharging pressure is relieved when the supercharging pressure is equal to or higher than a predetermined pressure. Thus, a surge noise at the time of deceleration can be reduced, and disconnection of the intake system piping and overshoot of the supercharging pressure can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an internal combustion engine with a supercharger and a wastegate valve control device according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a procedure for determining an abnormality of a knock sensor.
FIG. 3 is a flowchart showing a control procedure of a wastegate valve driving mechanism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Cylinder, 3 ... Piston, 4 ... Intake passage, 5 ... Exhaust passage, 6 ... Air cleaner, 7 ... Intercooler, 8 ... Throttle valve,
10: supercharger, 11: turbine, 12: compressor,
20 ... exhaust bypass passage, 21 ... waste gate valve, 23 ... waste gate valve driving mechanism, 24 ... diaphragm type actuator, 25 ... pressure guide passage, 26 ... waste gate solenoid valve, 27 ... waste gate solenoid, 28 ... orifice,
30 ... air bypass passage, 31 ... air bypass valve mechanism, 32 ... relief valve, 35 ... air bypass valve, 36 ... air bypass solenoid,
50 ... ECU.

Claims (1)

A supercharger including a turbine disposed in an exhaust passage and a compressor disposed in an intake passage, a wastegate valve interposed in a bypass passage bypassing the turbine of the supercharger in the exhaust passage, and the wastegate valve. In the internal combustion engine with a supercharger equipped with a wastegate valve drive mechanism to drive,
An air bypass valve mechanism for communicating and blocking an air bypass passage that bypasses a compressor of the supercharger in the intake passage;
Control means for controlling the air bypass valve mechanism,
When the wastegate valve drive mechanism is determined to be abnormal, the control means controls the air bypass valve mechanism so as to make the air bypass passage communicable. Air bypass valve control device.

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