JP2011179336A - Supercharging system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mitigate or solve a response delay of supercharging in such a state that reacceleration is performed after deceleration, in an internal combustion engine with an exhaust turbosupercharger controlling supercharging pressure in a direction reducing the supercharging pressure by opening a waste gate valve when the supercharging pressure introduced into the control chamber of an actuator exceeds a set pressure. <P>SOLUTION: This supercharging system includes: a supercharging pressure introducing path 9 for introducing the supercharging pressure to the control chamber 82 of the actuator 8; a first operating valve 10 provided in the supercharging pressure introducing path 9; an intake air negative pressure introducing path 11 for introducing intake air negative pressure downstream of a throttle valve 14 to the control chamber 82; a second operating valve 12 provided in the intake air negative pressure introducing path 11; and a controller 13 (ECU) for closing the first operating valve 10 with the throttle valve 14 closed and also opening the second operating valve 12. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a supercharging system for an internal combustion engine including an exhaust turbocharger.

  In a turbocharger that rotates a turbine with engine exhaust and drives a compressor to supercharge intake air, a bypass and a waste gate valve are provided to bypass part of the exhaust gas without introducing it into the turbine. It is customary to adjust the supercharging pressure through opening and closing of the waste gate valve. The waste gate valve is driven by a diaphragm actuator in which supercharged air is introduced into a control chamber (diaphragm chamber) (see, for example, Patent Document 1).

  By the way, in a system equipped with a well-known waste gate valve, when the foot is released from the accelerator pedal to use the engine brake and the throttle valve is closed, a high boost pressure temporarily flows into the control chamber, and the waste pressure is reduced. The gate valve is opened. Immediately after that, if the accelerator pedal is depressed to accelerate again, there will be a delay until the open wastegate valve closes, which combined with the turbo lag causes a problem that good reacceleration performance cannot be obtained. .

JP 2009-180112 A

  The present invention has been made paying attention to the above points, and an object of the present invention is to alleviate or eliminate a supercharge response delay in a situation where re-acceleration is performed after deceleration.

  That is, the supercharging system for an internal combustion engine according to the present invention controls the supercharging pressure to be reduced by opening the waste gate valve when the supercharging pressure introduced into the control chamber of the actuator exceeds the set pressure. In an internal combustion engine with an exhaust turbocharger that is obtained, a supercharging pressure introduction path for guiding a supercharging pressure to the control chamber, a first on-off valve provided in the supercharging pressure introduction path, An intake negative pressure introduction path for introducing intake negative pressure downstream of the throttle valve to the control chamber, a second opening / closing valve provided in the intake negative pressure introduction path, and the first opening / closing in a situation where the throttle valve is closed And a controller for closing the valve and opening the second on-off valve.

  In such a case, when the engine brake is used with the throttle valve closed, the intake negative pressure downstream of the throttle valve can be guided to the control chamber of the actuator, and the waste gate valve can be reliably closed. Therefore, at the time of reacceleration, there is no delay until the open waste gate valve is closed.

  ADVANTAGE OF THE INVENTION According to this invention, the response delay of the supercharging at the time of performing reacceleration after deceleration can be relieve | eliminated or eliminated.

The figure which shows the outline | summary of the supercharging system of the internal combustion engine which concerns on one Embodiment of this invention. Action | operation explanatory drawing which concerns on the same embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  An exhaust turbocharger 1 according to the present embodiment is mounted on, for example, an automobile internal combustion engine, and receives an energy of exhaust gas discharged from the internal combustion engine, that is, an exhaust turbine that rotates by receiving exhaust pressure, and an exhaust turbine. The compressor 3 driven by 2 is an element. The air sucked through the air cleaner 4 is compressed by the compressor 3 and supplied to the internal combustion engine. In addition, a bypass passage 6 that bypasses the exhaust turbine 2 is formed, and a waste gate valve 7 is interposed in the bypass passage 6. The inner diameter of the bypass passage 6 is about 0.6 to 1.0 times the wheel diameter of the exhaust turbine 2. The waste gate valve 7 is opened and closed by a diaphragm actuator 8.

The actuator 8 is provided with a diaphragm 81 elastically biased by a pressure adjusting spring 83 and its control chamber 82 (diaphragm chamber). When the pressure in the control chamber 82 exceeds a predetermined set pressure P ₀ , the pressure is adjusted. The diaphragm 81 is displaced against the urging force of the spring 83 and moves the operating rod 84 forward. The waste gate valve 7 is driven by the operating rod 84. That is, the waste gate valve 7 opens when the pressure in the control chamber 82 is equal to or higher than the set pressure P ₀ .

  Therefore, in this embodiment, the supercharging pressure introduction path 9 for guiding the supercharging pressure downstream of the compressor 3 to the control chamber 82, the first on-off valve 10 provided in the supercharging pressure introduction path 9, An intake negative pressure introduction path 11 for guiding intake negative pressure downstream of the throttle valve 14 to the control chamber 82, a second on-off valve 12 provided in the intake negative pressure introduction path 11, the first on-off valve 10 and A controller 13 capable of individually opening and closing the second opening / closing valve 12 is provided.

  The supercharging pressure introduction path 9 communicates the intake passage 5 downstream of the compressor 3 and the control chamber 82.

  The first on-off valve 10 can transition between a closed state in which the supercharging pressure introduction path 9 is blocked and an open state in which the supercharging pressure introduction path 9 is opened. The first on-off valve 10 is, for example, a valve body that is operated by an electromagnetic actuator, and by applying a control voltage signal (pulse voltage) having a duty ratio that defines the length of the open time to the electromagnetic actuator, The opening can be controlled according to the duty ratio.

  The intake negative pressure introduction path 11 communicates the intake passage 5 (surge tank 15 in the illustrated example) downstream of the throttle valve 14 and the control chamber 82.

  The second on-off valve 12 can transition between a closed state in which the intake negative pressure introduction path 11 is blocked and an open state in which the intake negative pressure introduction path 11 is opened. The second on-off valve 12 can also be an electromagnetic valve similar to the first on-off valve 10, for example.

  The intake negative pressure introduction path 11 merges with the supercharging pressure introduction path 9 before the control chamber 82. The junction is located between the first opening / closing valve 10 and the second opening / closing valve 12. In the present embodiment, the control chamber 82 of the actuator 8 does not directly communicate with the atmospheric pressure.

In each place of the internal combustion engine, in order to detect various situations of the internal combustion engine, an intake pressure sensor 16 that detects the intake pressure (supercharging pressure) in the surge tank 15 and a throttle that detects the opening of the throttle valve 14. An opening sensor 17, a water temperature sensor 18 for detecting the cooling water temperature of the internal combustion engine, a rotation speed sensor 19 for detecting the engine speed, an O ₂ sensor 20 for detecting the air-fuel ratio of the exhaust gas, and the like are attached.

  A controller 13 (ECU) that receives and processes signals from these sensors and controls the operating state of the internal combustion engine is a microcomputer system including a CPU, a RAM, a ROM, a flash memory, an I / O interface, and the like. . Various control programs are stored in the ROM or flash memory, and the programs are read into the RAM and decoded by the CPU. The controller 13 controls the fuel injection amount, the ignition timing, and other various controls according to the program.

  Hereinafter, the opening / closing control of the waste gate valve 7 in the supercharging system of the present embodiment will be described in detail with reference to FIG.

First, in a situation where it is desired to perform supercharging of intake air by the exhaust turbo supercharger 1, the controller 13 opens the throttle valve 14 to a required opening as shown in FIG. Both the valve 10 and the second opening / closing valve 12 are closed. At this time, the intake pressure P ₁ in the surge tank 15 is lower than a predetermined maximum boost pressure (set pressure P _s ). The supercharged air downstream of the compressor 3 does not flow into the control chamber 82 of the actuator 8 and the waste gate valve 7 is closed. Therefore, the entire exhaust gas is supplied to the exhaust turbine 2 and the compressor 3 is driven.

Next, in a situation where the intake pressure P ₁ in the surge tank 15 exceeds the set pressure P _s , the controller 13 opens the first on-off valve 10 as shown in FIG. The second opening / closing valve 12 is closed. As a result, a part of the supercharged air downstream of the compressor 3 flows into the control chamber 82 of the actuator 8. At this time, when the supercharging pressure P ₂ upstream of the throttle valve 14 exceeds the set pressure P ₀ , the diaphragm 81 is displaced against the biasing force of the pressure regulating spring 83 and the waste gate valve 7 is opened. Thereby, a part of the exhaust gas is bypassed and not supplied to the exhaust turbine 2, and supercharging by the compressor 3 is appropriately suppressed.

Further, in the situation where the engine load is lower than the predetermined load, when supercharging is not required, the controller 13 opens the first on-off valve 10 as shown in FIG. Then, the second on-off valve 12 is closed. As a result, a part of the supercharged air downstream of the compressor 3 flows into the control chamber 82 of the actuator 8. At this time, when the supercharging pressure P ₂ upstream of the throttle valve 14 exceeds the set pressure P ₀ , the diaphragm 81 is displaced against the biasing force of the pressure regulating spring 83 and the waste gate valve 7 is opened. Thereby, the supercharging by the compressor 3 is suppressed, the pump loss due to the supercharging in the low rotation range is reduced, and the excessive fuel is not injected without applying the supercharging pressure in a scene where the supercharging pressure is unnecessary. This improves fuel efficiency.

In addition, in a situation where the throttle valve 14 is closed, as shown in FIG. 2D, the controller 13 closes the first opening / closing valve 10 and opens the second opening / closing valve 12. To do. In other words, the intake negative pressure generated downstream of the throttle valve 14, in other words, the intake negative pressure P ₁ in the surge tank 15 is introduced into the control chamber 82 of the actuator 8 through the intake negative pressure introduction path 11. Then, the waste gate valve 7 is strongly closed.

  When the throttle valve 14 is opened again to re-accelerate after the throttle valve 14 is closed, the state shown in FIG. 2D can be quickly changed to the state shown in FIG. 2B. . Alternatively, after the throttle valve 14 is closed, when the engine load becomes a predetermined load or less, the state shifts from the state shown in FIG. 2D to the state shown in FIG.

  As described above, according to the supercharging system of the present embodiment, in a situation in which the throttle valve 14 is closed, the first on-off valve 10 is closed and the second on-off valve 12 is opened. As a result, intake negative pressure is introduced into the control chamber 82, the diaphragm 81 and the operating rod 84 are drawn into the control chamber 82 side, and the waste gate valve 7 can be strongly closed. Therefore, when the throttle valve 14 is opened again immediately after the throttle valve 14 is closed, there is no delay until the waste gate valve 7 is closed, and the response delay of supercharging when reacceleration after deceleration is reduced. Or it can be solved.

  In addition, by introducing intake negative pressure into the control chamber 82 of the actuator 8 and closing the waste gate valve 7, it is possible to prevent chattering that the waste gate valve 7 frequently opens and closes due to fluctuations in the supercharging pressure. it can.

  The present invention is not limited to the embodiment described above.

  For example, the first on-off valve and the second on-off valve are not limited to electromagnetic valves whose opening degree can be controlled by DUTY.

  In addition, various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Exhaust turbocharger 7 ... Waste gate valve 8 ... Actuator 82 ... Control chamber 9 ... Supercharging pressure introduction path 10 ... 1st on-off valve 11 ... Intake negative pressure introduction path 12 ... 2nd on-off valve 13 ... Controller 14 ... Throttle valve

Claims (1)

In an internal combustion engine with an exhaust turbocharger that can be controlled in a direction to reduce the supercharging pressure by opening a waste gate valve when the supercharging pressure introduced into the control chamber of the actuator exceeds a set pressure ,
A supercharging pressure introduction path for guiding supercharging pressure to the control chamber;
A first on-off valve provided in the supercharging pressure introduction path;
An intake negative pressure introduction path for guiding intake negative pressure downstream of the throttle valve to the control chamber;
A second on-off valve provided in the intake negative pressure introduction path;
A supercharging system for an internal combustion engine, comprising: a controller for closing the first open / close valve and opening the second open / close valve in a situation where the throttle valve is closed.

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