JP2012067614A - Device for controlling compressor outlet pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil from being sucked out of an oil seal part disposed at the back surface of a compressor impeller.SOLUTION: A compressor outlet pressure regulator device 200 (a valve open/close control unit 71) is provided for regulating air pressure at the outlet of the compressor 51. The compressor outlet pressure regulator device includes: an outlet pressure recognition part 712 for automatically recognizing a compressor outlet pressure P3 that is the air pressure at the outlet of the compressor 51; a negative pressure determination part 713 for determining whether the compressor outlet pressure P3 is a negative pressure; and an indication part 714 for closing a by-pass valve 14 when the negative pressure determination part 713 has determined that the compressor outlet pressure P3 is a negative pressure.

Description

  The present invention relates to a compressor provided in an intake passage of an internal combustion engine mounted on a vehicle, a supercharger having a turbine provided in an exhaust passage of the internal combustion engine, an intake passage upstream of the compressor, and the The present invention relates to a compressor outlet pressure control device that includes a bypass passage that communicates with an intake passage at the outlet of a compressor, and a bypass valve that opens and closes the bypass passage, and controls the air pressure at the outlet of the compressor.

  Conventionally, in order to suppress the occurrence of surging in a compressor of a turbocharger mounted on a vehicle, a bypass valve provided in a bypass passage that connects an intake passage on the upstream side of the compressor and an intake passage on the downstream side of the compressor has been provided. A technique for controlling the air pressure at the outlet of the compressor by controlling the opening and closing is known.

  For example, a technique is disclosed in which, when decelerating, a bypass valve is opened to open a bypass passage so that the pressure on the downstream side of the compressor is released to the intake passage on the upstream side to prevent the occurrence of surge noise (patent) Reference 1).

JP-A-10-246118

  However, in the technique described in Patent Document 1, when the intake passage at the outlet of the compressor has a negative pressure, the oil may be sucked out from the oil seal portion disposed on the rear surface of the impeller of the compressor. Further, when oil is sucked out, the sucked out oil burns in the cylinder to generate white smoke, and there is a concern that the amount of oil consumption increases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a compressor outlet pressure control device capable of suppressing oil from being sucked out from an oil seal portion disposed on the back surface of an impeller of a compressor. It is said.

  In order to solve the above problems, a compressor outlet pressure control device according to the present invention is configured as follows.

  That is, a compressor outlet pressure control device according to the present invention includes a compressor provided in an intake passage of an internal combustion engine mounted on a vehicle, a supercharger having a turbine provided in an exhaust passage of the internal combustion engine, A compressor outlet pressure control device, comprising: a bypass passage that communicates an intake passage on the upstream side of the compressor and an intake passage at the outlet of the compressor; and a bypass valve that opens and closes the bypass passage, and controls the air pressure at the outlet of the compressor An outlet pressure recognition means for recognizing a compressor outlet pressure that is an air pressure at an outlet of the compressor, a negative pressure determination means for determining whether or not the compressor outlet pressure is a negative pressure, and the negative pressure determination means When the compressor outlet pressure is determined to be negative, the bypass valve is opened. A valve opening and closing means for the state, a compressor outlet pressure control device comprising a.

  According to the compressor outlet pressure control device having such a configuration, when the compressor outlet pressure, which is the air pressure at the outlet of the compressor, is negative, the bypass valve is opened. Since the upstream intake passage and the intake passage at the outlet of the compressor communicate with each other and the compressor outlet pressure approaches the atmospheric pressure, the oil is sucked out from the oil seal portion disposed on the back surface of the impeller of the compressor. Can be suppressed.

  Also, the compressor outlet pressure control device according to the present invention provides vehicle state determination means for determining whether the state of the vehicle is any of a state at the start of the internal combustion engine, an idling time, and a deceleration state. And the negative pressure determining means determines that the vehicle state is determined by the vehicle state determining means to be one of a start state, an idling time, and a deceleration state of the internal combustion engine. For example, it is preferable to determine whether or not the compressor outlet pressure is a negative pressure.

  According to the compressor outlet pressure control apparatus having such a configuration, it is determined that the state of the vehicle is one of a state at the start of the internal combustion engine, an idling time, and a deceleration time, and the compressor outlet pressure is determined. When the pressure is determined to be negative pressure, the bypass valve is opened, so that it is possible to more accurately suppress the oil from being sucked out from the oil seal portion disposed on the back surface of the compressor impeller. it can.

  That is, if the compressor outlet pressure is negative, when the bypass valve is opened, it is determined to be temporarily negative for some reason (for example, due to erroneous detection of the pressure sensor). Sometimes, since the bypass valve is opened, the bypass valve may not be accurately opened.

  Further, in the compressor outlet pressure control device according to the present invention, the valve opening / closing means is controlled by the vehicle state determination means so that the state of the vehicle is any of a state when the internal combustion engine is started, when idling, and when decelerating. However, when it is determined that this is not the case, it is preferable to control the opening and closing of the bypass valve so as to avoid the occurrence of surging in the compressor.

  According to the compressor outlet pressure control apparatus having such a configuration, it is possible to avoid the occurrence of surging in the compressor when the state of the vehicle is not any of the starting state, the idling state, and the deceleration state of the internal combustion engine. Since the bypass valve is controlled to open and close as much as possible, the surging in the compressor can be avoided by opening and closing the bypass valve.

  The compressor outlet pressure control device according to the present invention further includes an outlet pressure sensor for detecting the compressor outlet pressure, and the outlet pressure recognition means recognizes the compressor outlet pressure based on an output signal from the outlet pressure sensor. It is preferable to do.

  According to the compressor outlet pressure control apparatus having such a configuration, the compressor outlet pressure is detected by the outlet pressure sensor, and the compressor outlet pressure is recognized based on the detected output signal of the compressor outlet pressure. Can be accurately recognized, and the bypass valve can be accurately opened.

  The compressor outlet pressure control apparatus according to the present invention includes a throttle opening sensor that detects a throttle opening of the internal combustion engine, an intake manifold pressure sensor that detects an intake manifold pressure that is an air pressure of the intake manifold of the internal combustion engine, A flow rate sensor for detecting an air flow rate upstream of the compressor, and the outlet pressure recognition means determines the compressor outlet pressure based on the throttle opening, the intake manifold pressure, and the air flow rate. It is preferable to estimate.

  According to the compressor outlet pressure control device having such a configuration, the compressor outlet pressure is estimated based on the throttle opening, the intake manifold pressure, and the air flow rate upstream of the compressor. The compressor outlet pressure can be recognized without newly arranging.

  In the compressor outlet pressure control apparatus according to the present invention, it is preferable that the bypass valve is disposed in order to avoid occurrence of surging in the compressor.

  According to the compressor outlet pressure control device having such a configuration, a bypass valve arranged to avoid the occurrence of surging in the compressor without newly providing a bypass valve or the like is used on the rear surface of the compressor impeller. It is possible to suppress oil from being sucked out from the disposed oil seal portion.

  In the compressor outlet pressure control apparatus according to the present invention, the bypass valve is preferably an electric valve.

  According to the compressor outlet pressure control apparatus having such a configuration, the bypass valve can be opened regardless of the state of the vehicle, so that oil is sucked from the oil seal portion disposed on the back surface of the compressor impeller. It can suppress more effectively.

  The compressor outlet pressure control device according to the present invention avoids occurrence of surging in the compressor when the valve opening / closing means determines that the compressor outlet pressure is not negative by the negative pressure determining means. Therefore, it is preferable to control the opening and closing of the bypass valve.

  According to the compressor outlet pressure control apparatus having such a configuration, when the compressor outlet pressure is not a negative pressure, the bypass valve is controlled to be opened and closed in order to avoid the occurrence of surging in the compressor. Therefore, occurrence of surging in the compressor can be avoided.

  In addition, the compressor outlet pressure control device according to the present invention includes: a stop unit that stops idling of the internal combustion engine when the vehicle satisfies a preset idling stop condition; and the stop unit stops the idling of the internal combustion engine. It is preferable to include restarting means for restarting the internal combustion engine when preset restart conditions are satisfied after idling is stopped.

  According to the compressor outlet pressure control device having such a configuration, when a preset idling stop condition is satisfied, idling of the internal combustion engine is stopped (fuel supply is stopped), and a preset restart condition is satisfied. In this case, since the internal combustion engine is restarted, the frequency at which the compressor outlet pressure, which is the air pressure at the outlet of the compressor, becomes a negative pressure increases. Therefore, the oil seal disposed on the back surface of the impeller of the compressor The effect of suppressing the oil from being sucked out from the portion becomes obvious.

  According to the compressor outlet pressure control device according to the present invention, it is possible to suppress the oil from being sucked out from the oil seal portion disposed on the back surface of the impeller of the compressor.

It is a conceptual diagram which shows an example of the internal combustion engine system to which the compressor outlet pressure control apparatus which concerns on this invention is applied. It is sectional drawing which shows an example of the supercharger to which the compressor outlet pressure control apparatus which concerns on this invention is applied. FIG. 3 is a partial cross-sectional view illustrating an example of a situation in which oil is sucked out from an oil seal portion on the back surface of an impeller in the supercharger illustrated in FIG. 2. It is a block diagram which shows an example of the compressor outlet pressure control apparatus which concerns on this invention. It is a flowchart which shows an example of operation | movement of the valve opening / closing control part shown in FIG. It is a graph which shows an example of the effect of the opening / closing control of a bypass valve by the valve opening / closing control part shown in FIG.

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

-Configuration of internal combustion engine system 100-
FIG. 1 is a conceptual diagram showing an example of an internal combustion engine system 100 to which a compressor outlet pressure control device according to the present invention is applied. First, a schematic configuration of the internal combustion engine system 100 will be described below with reference to FIG. An internal combustion engine system 100 shown in FIG. 1 includes an engine 2, an exhaust circulation device 3, an intake passage 1 of the engine 2, an exhaust passage 4 of the engine 2, a turbocharger 5, and an engine control ECU (Electronic Control Unit) 7. (Refer to FIG. 4). Here, the engine 2 corresponds to an “internal combustion engine”, and the turbocharger 5 corresponds to a “supercharger”.

  Here, the engine 2 is configured as an in-line four-cylinder gasoline engine. The engine 2 includes a cylinder block and a cylinder head, and four combustion chambers 21 are formed inside the cylinder block. The cylinder head is formed with an intake port for supplying intake air to the combustion chamber 21 and an exhaust port for discharging exhaust gas generated in the combustion chamber 21 to the outside. In the present embodiment, the case where the engine 2 is an in-line four-cylinder gasoline engine will be described. However, the engine 2 may be another type of engine such as a diesel engine, the type of the engine 2, and the number of cylinders. Also, other types and other cylinders may be used.

  An intake passage 1 is connected to an intake port formed in a cylinder head of the engine 2 via an intake manifold 22. In the middle of the intake passage 1, a main intake passage 12 and a bypass passage 13 that merge after branching into two are formed in parallel. A compressor 51 of the turbocharger 5 is disposed in the main intake passage 12. A bypass valve 14 is disposed in the bypass passage 13. The bypass valve 14 is controlled to open and close by a control signal transmitted from the engine control ECU 7 (see FIG. 4). The bypass valve 14 is an electric valve. Further, the bypass valve 14 is arranged to avoid the occurrence of surging in the compressor 51.

  Thus, since the bypass valve 14 is arranged to avoid the occurrence of surging in the compressor 51, as will be described later with reference to FIG. 6 without newly providing a bypass valve or the like, By using the bypass valve 14 arranged to avoid the occurrence of surging in the compressor 51, it is possible to suppress the oil from being sucked out from the oil seal 581 provided on the back surface of the impeller 511 of the compressor 51 (FIG. 3, see FIG.

  As will be described later with reference to FIGS. 5 and 6, the bypass valve 14 is opened to prevent oil from being sucked out from the oil seal 581 disposed on the back surface of the impeller 511 (see FIG. 2) of the compressor 51. In this case, since the pressure at the outlet of the compressor 51 is a negative pressure, air flows in the direction of the arrow V1 in the bypass passage 13. On the other hand, when the bypass valve 14 is opened to suppress surging, air flows in the direction of the arrow V2 in the bypass passage 13.

  An air cleaner 11 for filtering the intake air is disposed further upstream of the merging position on the intake upstream side of the main intake passage 12 and the bypass passage 13 of the intake passage 1. Further, the intake air flow rate Q (hereinafter referred to as “intake air”) is introduced into the intake passage 1 downstream of the air cleaner 11 (between the air cleaner 11 and the merging position on the intake upstream side of the main intake passage 12 and the bypass passage 13). A flow rate sensor 61 for detecting “amount” is also provided. A detection signal indicating the air flow rate Q detected by the flow sensor 61 is input to the engine control ECU 7.

  An intercooler 15 that cools the air compressed by the compressor 51 is disposed further downstream of the merging position on the intake downstream side of the main intake passage 12 and the bypass passage 13 of the intake passage 1. Further, an air pressure at the outlet of the compressor 51 (hereinafter referred to as “compressor”) is provided in the intake passage 1 on the upstream side of the intercooler 15 (between the merge position on the intake downstream side of the main intake passage 12 and the bypass passage 13 and the intercooler 15). An outlet pressure sensor 62 that detects “outlet pressure”) is provided. A detection signal indicating the compressor outlet pressure P3 detected by the outlet pressure sensor 62 is input to the engine control ECU 7.

  Further, a throttle valve 16 is provided on the intake downstream side of the intake passage 1 from the intercooler 15 (between the intercooler 15 and the intake manifold 22). The throttle valve 16 is configured such that the opening degree is controlled by a control signal transmitted from the engine control ECU 7 and the flow rate of the intake air flowing into the intake manifold 22 can be adjusted.

  The throttle valve 16 is provided with a throttle opening sensor 64 that detects a throttle opening φ that is the opening of the throttle valve 16. A detection signal indicating the throttle opening φ detected by the throttle opening sensor 64 is input to the engine control ECU 7 (see FIG. 4). Further, an intake manifold pressure sensor that detects an intake manifold pressure Pb that is a pressure of air sucked into the intake manifold 22 is provided in the intake passage 1 downstream of the throttle valve 16 (between the throttle valve 16 and the intake manifold 22). 63 is arranged. A detection signal indicating the intake manifold pressure Pb detected by the intake manifold pressure sensor 63 is input to the engine control ECU 7.

  An exhaust passage 4 is connected to an exhaust port formed in the cylinder head of the engine 2 via an exhaust manifold 23. Further, the engine 2 has an exhaust gas recirculation device 3 that reduces the combustion temperature by reducing the exhaust gas discharged into the exhaust passage 4 back to the intake passage 1 as EGR (Exhaust Gas Recirculation) gas, thereby reducing the amount of NOx emission. Is provided. In the exhaust circulation device 3, the EGR gas is configured to be returned to the intake passage 1 through an exhaust circulation passage 31 that connects the exhaust passage 4 and the intake passage 1. Further, an EGR cooler 32 that cools the EGR gas is interposed in the exhaust circulation passage 31. The EGR gas is cooled by the EGR cooler 32 when returning from the exhaust passage 4 to the intake passage 1 through the exhaust circulation passage 31.

  In the exhaust passage 4, a main exhaust passage 42 and a bypass passage 43 that merge after branching into two are formed in parallel. A turbine 52 of the turbocharger 5 is disposed in the main exhaust passage 42. A bypass valve 44 is disposed in the bypass passage 43. The bypass valve 44 is controlled to open and close by a control signal transmitted from the engine control ECU 7, and is configured to be able to adjust the flow rate of the exhaust gas passing through the bypass passage 43.

  The turbocharger 5 includes a compressor 51, a turbine 52, and a turbine shaft 53. The compressor 51 includes a plurality of impellers 511 (see FIG. 2) on the outer peripheral surface. The compressor 51 is formed of a lightweight aluminum alloy, synthetic resin, or the like in order to suppress turbo lag.

  The turbine 52 includes a plurality of blades on the outer peripheral surface. Further, since the turbine 52 is exposed to high-temperature (for example, 600 to 800 ° C.) exhaust gas, it is made of heat-resistant steel (carbon steel) or the like. The turbine 52 is connected via a turbine shaft 53 and is configured to be rotatable integrally with the compressor 51.

  The compressor 51 and the turbine 52 are integrally connected by a turbine shaft 53 made of metal (for example, cast iron) so as to be rotatable. That is, the compressor 51, the turbine 52, and the turbine shaft 53 are disposed on the same axis, and are assembled together to constitute a turbo rotor.

  Since the turbocharger 5 is configured to rotate integrally as described above, when the turbine 52 is rotationally driven by the energy of the exhaust gas, the rotational force of the turbine 52 is transmitted to the compressor 51 via the turbine shaft 53. The As a result, the compressor 51 is driven to rotate, and the turbocharger 5 performs the supercharging operation.

  The engine control ECU 7 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU reads and executes a control program or the like stored in a ROM or the like. The ROM is a memory that stores a control program and the like in advance. The RAM is a memory used as a working memory, a temporary storage memory, or the like. Here, the engine control ECU 7 reads out a control program stored in the ROM and executes it by the CPU, thereby performing various controls relating to the operation of the engine 2, and functionally, the valve opening / closing control unit 71, engine start It functions as the stop control unit 72 (see FIG. 4).

-Configuration of turbocharger 5-
FIG. 2 is a cross-sectional view showing an example of a turbocharger 5 to which the compressor outlet pressure control device according to the present invention is applied. Hereinafter, the configuration of the turbocharger 5 will be described with reference to FIG. As described above with reference to FIG. 1, the turbocharger 5 includes the compressor 51, the turbine 52, and the turbine shaft 53.

  As shown in FIG. 2, the turbocharger 5 includes a housing 54 that houses a compressor 51, a turbine 52, and a turbine shaft 53. The housing 54 includes a compressor housing 541 that houses the compressor 51, a turbine housing 542 that houses the turbine 52, and a bearing housing 543 that houses the turbine shaft 53. Further, the compressor housing 541 has a vortex chamber 59 for supplying compressed air discharged from the impeller 511 of the compressor 51 to the intake manifold 22 via the intercooler 15 shown in FIG. It is arranged. Further, the bearing housing 543 is provided with rolling bearings 55 and 56 that rotatably support the turbine shaft 53.

  Here, the rolling bearings 55 and 56 are both known angular ball bearings. In this embodiment, the case where the turbine shaft 53 is rotatably supported by the rolling bearings 55 and 56 will be described. However, the turbine shaft 53 can be rotated by other types of bearings (for example, an oil film bearing). It may be a supported form.

  Oil is supplied to the rolling bearings 55 and 56 for lubrication and cooling via oil passages 551 and 561 formed in the housing 54, respectively. Further, the oil supplied to the rolling bearings 55 and 56 is configured to pass from the rolling bearings 55 and 56 to the outside (both left and right ends). In the following description, for the sake of convenience, an oil seal structure and an oil discharge structure that prevent oil supplied to the rolling bearing 55 from entering the compressor housing 541 will be described.

  In order to prevent the oil supplied to the rolling bearing 55 and having passed to the outside (here, the left end side) from leaking to the compressor housing 541, an oil seal is provided on the outside (left end side) of the rolling bearing 55. 581 is provided. The oil seal 581 is mounted in an outer peripheral groove provided on the outer periphery of a seal sleeve 58 that is fitted on the compressor 51 side of the turbine shaft 53. Further, the oil seal 581 is in contact with the inner peripheral surface of the seal plate 541 a of the compressor housing 541. In the present embodiment, the oil seal 581 is formed of a seal ring having a rectangular cross-sectional shape, but may be formed of another type of seal ring (for example, an O-ring).

  Further, an oil discharge system 57 for discharging the oil supplied to the rolling bearing 55 is formed inside the oil seal 581 provided in the seal sleeve 58. The oil discharge system 57 includes an oil chamber 571, an oil deflector 572, and an oil discharge passage 573. The oil chamber 571 is an annular space for storing the oil blocked by the oil seal 581, and is formed along the outer periphery of the turbine shaft 53. The oil deflector 572 guides the oil received in the oil chamber 571 to the oil discharge passage 573. The oil guided to the oil drain passage 573 is recovered to the oil supply source side.

-Oil suction phenomenon-
FIG. 3 is a partial cross-sectional view showing an example of a situation in which oil is sucked out from the oil seal 581 on the back surface of the impeller 511 in the turbocharger 5 shown in FIG. Hereinafter, a phenomenon in which oil is sucked out from the oil seal 581 on the back surface of the impeller 511 of the compressor 51 will be described with reference to FIG. When the vehicle is in any state of starting the engine 2, idling, and decelerating, the air pressure on the discharge side of the compressor 51 (such as in the vortex chamber 59) may be negative. is there.

  For example, at the time of cranking, idling, and deceleration (coast running), the accelerator is in an “OFF” state, and the throttle opening φ of the throttle valve 16 is a “fully closed position (idle opening)” in terms of control. In this state, during the intake stroke of the engine 2, the air pressure of the intake manifold 22 becomes a large negative pressure as an absolute value, and the air on the discharge side (in the vortex chamber 59 and the like) of the compressor 51 passes through the clearance of the throttle valve 16. Since the air is sucked in, the pressure on the discharge side of the compressor 51 (in the vortex chamber 59 and the like) also becomes negative. At this time, since the air cleaner 11 is provided, it is difficult for outside air to be inhaled. Here, the idle opening is an opening required for ISC (Idle Speed Control) control.

  Thus, when the pressure of the air on the discharge side of the compressor 51 (in the vortex chamber 59 or the like) becomes a negative pressure, as shown by an arrow V3 in FIG. 3, the oil seal 581 passes through the impeller 511 rear surface of the compressor 51, Oil is sucked into the vortex chamber 59. The sucked out oil is supplied to the engine 2 to generate abnormal combustion and white smoke. Moreover, since oil is sucked out, there is a concern that the amount of oil consumption increases.

  Further, as described above, the air pressure on the discharge side (in the vortex chamber 59 or the like) of the compressor 51 may be negative in various states of the vehicle. Therefore, as described with reference to FIG. 1, since the bypass valve 14 is an electric valve, the bypass valve 14 can be opened regardless of the state of the vehicle. Therefore, it is possible to more effectively suppress the oil from being sucked out from the oil seal 581 provided on the back surface of the impeller 511 of the compressor 51.

−Configuration of Compressor Outlet Pressure Control Device 200−
FIG. 4 is a block diagram showing an example of the compressor outlet pressure control apparatus 200 according to the present invention. Hereinafter, the configuration of the compressor outlet pressure control apparatus 200 will be described with reference to FIG. The compressor outlet pressure control device 200 performs opening / closing control of the bypass valve 14 described with reference to FIG. 1, and includes a part of the engine control ECU 7 (valve opening / closing control unit 71, engine start / stop control unit 72), And an outlet pressure sensor 62.

  As shown in FIG. 1, the outlet pressure sensor 62 is disposed in the intake passage 1 upstream of the intercooler 15 (between the merge position on the intake downstream side of the main intake passage 12 and the bypass passage 13 and the intercooler 15). And a sensor that detects the air pressure at the outlet of the compressor 51 (hereinafter referred to as “compressor outlet pressure”). A detection signal indicating the compressor outlet pressure P3 detected by the outlet pressure sensor 62 is input to the engine control ECU 7.

  The valve opening / closing control unit 71 performs opening / closing control of the bypass valve 14, and functionally includes a vehicle state determination unit 711, an outlet pressure recognition unit 712, a negative pressure determination unit 713, an instruction unit 714, and surging avoidance. A control unit 715 is provided.

  The vehicle state determination unit 711 is a functional unit that determines whether the state of the vehicle is one of the state at the start of the engine 2, the idling time, and the deceleration state. The vehicle state determination unit 711 corresponds to “vehicle state determination unit”. Here, the vehicle state determination unit 711 determines that the vehicle is in a state of being decelerated based on, for example, a detection signal from a vehicle speed sensor (or a wheel speed sensor).

  The outlet pressure recognition unit 712 is a functional unit that recognizes the compressor outlet pressure P3 that is the air pressure at the outlet of the compressor 51. The outlet pressure recognition unit 712 corresponds to “outlet pressure recognition means”. Specifically, the outlet pressure recognition unit 712 recognizes the compressor outlet pressure P3 based on an output signal from the outlet pressure sensor 62 (a detection signal indicating the compressor outlet pressure P3).

  Thus, since the outlet pressure recognition unit 712 recognizes the compressor outlet pressure P3 based on the output signal from the outlet pressure sensor 62, the compressor outlet pressure P3 can be accurately recognized.

  In the present embodiment, the case where the outlet pressure recognition unit 712 recognizes the compressor outlet pressure P3 based on the output signal from the outlet pressure sensor 62 will be described. The outlet pressure recognition unit 712 detects by the throttle opening sensor 64. The compressor outlet pressure P3 may be estimated based on the throttle opening φ, the intake manifold pressure Pb detected by the intake manifold pressure sensor 63, and the air flow rate Q detected by the flow sensor 61. In this case, the compressor outlet pressure P3 can be recognized without newly arranging a sensor such as the outlet pressure sensor 62.

  Specifically, data indicating the relationship between the throttle opening φ, the intake manifold pressure Pb and the air flow rate Q, and the compressor outlet pressure P3 is acquired in advance through experiments or the like, and the acquired data is tabulated, for example. Store in the data table. Then, the outlet pressure recognition unit 712 may recognize the compressor outlet pressure P3 by reading out the compressor outlet pressure P3 corresponding to the detected throttle opening φ, the intake manifold pressure Pb, and the air flow rate Q from the data table.

  When the vehicle state determination unit 711 determines that the vehicle state is one of the states when the engine 2 starts, idling, and deceleration, the negative pressure determination unit 713 outputs the outlet pressure recognition unit. 712 is a functional unit that determines whether or not the compressor outlet pressure P3 recognized by 712 is a negative pressure. The negative pressure determination unit 713 corresponds to “negative pressure determination means”.

  The instruction unit 714 is a functional unit that opens the bypass valve 14 when the negative pressure determination unit 713 determines that the compressor outlet pressure P3 is negative. The instruction unit 714 also performs surging avoidance control when the surging avoidance control unit 715 outputs instruction information for opening the bypass valve 14 or instruction information for opening the bypass valve 14. This is a functional unit that controls opening and closing of the bypass valve 14 based on instruction information from the unit 715. The instruction unit 714 corresponds to a part of “valve opening / closing means”.

  The surging avoidance control unit 715, when the vehicle state determination unit 711 determines that the state of the vehicle is not any of the engine 2 starting, idling, and deceleration states, or a negative pressure determination unit When it is determined by 713 that the compressor outlet pressure P3 is not a negative pressure, the bypass valve 14 is controlled to be opened / closed in order to avoid the occurrence of surging in the compressor 51 (hereinafter, this opening / closing control is also referred to as “surging avoidance control”). This is a functional unit that outputs instruction information to that effect to the instruction unit 714. The surging avoidance control unit 715 corresponds to a part of “valve opening / closing means”.

  Specifically, the surging avoidance control unit 715 opens the bypass valve 14 and sets the air pressure at the outlet of the compressor 51 when, for example, it is estimated that a surging occurrence region A1 described later with reference to FIG. The occurrence of surging in the compressor 51 is avoided by reducing the pressure ratio to the air pressure at the inlet of the compressor 51.

  The engine start / stop control unit 72 stops idling of the engine 2 and restarts the engine 2 after being stopped, and functionally includes a stop unit 721 and a restart unit 722.

  The stop unit 721 is a functional unit that stops idling of the engine 2 (stops fuel supply) when a preset idling stop condition is satisfied. Here, the idling stop condition is, for example, that the ignition is “ON”, the vehicle speed sensor detects that the vehicle speed is “0”, and the brake pedal is depressed by the brake pedal sensor. Is a condition that is detected. The stop unit 721 corresponds to “stop means”.

  The restart unit 722 is a functional unit that restarts the engine 2 when idling of the engine 2 is stopped (fuel supply is stopped) by the stop unit 721 and a preset restart condition is satisfied. Here, the restart condition is, for example, whether it has been detected that the brake pedal depressing operation has been performed from the brake pedal sensor while idling of the engine 2 is stopped (fuel supply stopped) by the stop unit 721. Alternatively, it is a condition that it is detected from the accelerator pedal sensor that the accelerator pedal is depressed. The restart unit 722 corresponds to “restart means”.

  Thus, when the idling stop condition is satisfied, the idling of the engine 2 is stopped (fuel supply is stopped), and after the idling is stopped, the engine 2 is restarted when the restart condition is satisfied. Therefore, the engine 2 is frequently stopped and restarted. Therefore, since the frequency at which the compressor outlet pressure P3 becomes negative pressure increases, the effect of suppressing the oil from being sucked out from the oil seal 581 provided on the back surface of the impeller 511 of the compressor 51 is further manifested.

  In the present embodiment, the case where the engine control ECU 7 includes the engine start / stop control unit 72 has been described. However, the engine control ECU 7 may not include the engine start / stop control unit 72. In this case, the configuration of the engine control ECU 7 is simplified.

-Operation of the valve opening / closing control unit 71-
FIG. 5 is a flowchart showing an example of the operation of the valve opening / closing control unit 71 according to the present invention. Hereinafter, the operation of the valve opening / closing control unit 71 will be described with reference to FIG. First, in step S <b> 101, the vehicle state determination unit 711 determines whether the vehicle state is any of the states when the engine 2 is started, idling, and decelerating. If YES in step S101, the process proceeds to step S103. On the other hand, if NO at step S101, the process proceeds to step S107.

  In step S103, the outlet pressure recognition unit 712 recognizes the compressor outlet pressure P3, which is the air pressure at the outlet of the compressor 51, and the negative pressure determination unit 713 determines whether the compressor outlet pressure P3 is a negative pressure. Is done. If YES in step S103, the process proceeds to step S105. On the other hand, if NO at step S103, the process proceeds to step S107.

  In step S105, the instruction unit 714 outputs instruction information indicating that the bypass valve 14 is opened. Then, when the process in step S105 ends, the process returns to step S101.

  In step S107, the instruction unit 714 outputs instruction information to the effect that the bypass valve 14 is closed. When the process in step S107 ends, the process proceeds to step S109.

  In step S109, the bypass valve 14 is controlled to be opened and closed by the surging avoidance control unit 715 so as to avoid the occurrence of surging. Then, when the process in step S109 ends, the process returns to step S101.

  In this way, when it is determined that the state of the vehicle is any of the engine 2 starting, idling, and deceleration, and the compressor outlet pressure P3 is determined to be negative. Furthermore, since the bypass valve 14 is opened, it is possible to more accurately suppress the oil from being sucked out from the oil seal 581 provided on the back surface of the impeller 511 of the compressor 51 (see FIG. 6).

  That is, if the compressor outlet pressure P3 is negative, when the bypass valve 14 is opened, it is determined to be temporarily negative for some reason (for example, due to erroneous detection of the pressure sensor). Sometimes, since the bypass valve 14 is opened, there is a possibility that the bypass valve 14 cannot be accurately opened.

  Further, since the bypass valve 14 is controlled to open and close in order to avoid the occurrence of surging in the compressor 51 when the state of the vehicle is not any of the engine 2 starting, idling, and decelerating states, Occurrence of surging in the compressor 51 can be avoided by opening and closing the valve 14 (see FIG. 6).

  Further, when the compressor outlet pressure P3 is not a negative pressure, the bypass valve 14 is controlled to be opened and closed in order to avoid the occurrence of surging in the compressor 51. Therefore, the occurrence of surging in the compressor 51 is avoided by the opening and closing operation of the bypass valve 14. (See FIG. 6).

-Effects of opening / closing control of bypass valve 14-
FIG. 6 is a graph showing an example of the effect of opening / closing control of the bypass valve 14 by the valve opening / closing control unit 71 according to the present invention. Hereinafter, the effect of opening / closing control of the bypass valve 14 by the valve opening / closing control unit 71 will be described with reference to FIG. The horizontal axis of the graph shown in FIG. 6 is the air flow rate sucked into the compressor 51, and the vertical axis is the pressure ratio of the air pressure at the outlet of the compressor 51 to the air pressure at the inlet of the compressor 51.

  The graph G1 is a graph showing the boundary line of the surging occurrence region A1. The graph G2 is a graph showing the choke flow rate that is the maximum flow rate that can be pumped by the compressor 51. The graph G3 is a graph showing an example of the relationship between the pressure ratio and the air flow rate when the rotation speed of the compressor 51 is constant. Graph G4 is a graph showing an example of the behavior of the internal combustion engine system 100 when the surging avoidance control by the surging avoidance control unit 715 is not performed. When the surging avoidance control is not performed, as shown in the graph G4, the surging generation area A1 may be entered (= surging will occur).

  On the other hand, the graph G5 is a graph showing an example of the behavior of the internal combustion engine system 100 when the surging avoidance control by the surging avoidance control unit 715 is performed. Since the bypass valve 14 is opened by the surging avoidance control unit 715 when it is estimated that the surging occurrence area A1 is entered, the rise in the pressure ratio is suppressed and the surging occurrence area A1 is entered ( = Surging occurs) is avoided.

  As shown in FIG. 3, the region A <b> 2 is a vortex chamber in which the air pressure on the discharge side of the compressor 51 (in the vortex chamber 59 or the like) becomes negative, and the oil seal 581 passes through the back surface of the impeller 511 of the compressor 51. 59 is an area where oil is sucked out. Point P1 is a point indicating an example of the operating state of the internal combustion engine system 100 in which the bypass valve 14 is closed. In this state, since the point P1 is in the region A2, the pressure of the air on the discharge side of the compressor 51 (in the vortex chamber 59 or the like) becomes negative, and passes from the oil seal 581 to the rear surface of the impeller 511 of the compressor 51. Thus, oil is sucked into the vortex chamber 59.

  On the other hand, the point P2 is a point indicating an example of an operation state of the internal combustion engine system 100 when the bypass valve 14 is opened by the valve opening / closing control unit 71. Since the point P1 is outside the region A2, oil is not sucked into the vortex chamber 59 from the oil seal 581 via the back surface of the impeller 511 of the compressor 51.

  Thus, when the compressor outlet pressure P3, which is the air pressure at the outlet of the compressor 51, is a negative pressure, the bypass valve 14 is opened, so that the bypass passage 13 and the intake passage 1 upstream of the compressor 51 The intake passage 1 at the outlet of the compressor 51 is communicated and the compressor outlet pressure P3 is brought close to the atmospheric pressure, so that oil is prevented from being sucked out from the oil seal 581 provided on the back surface of the impeller 511 of the compressor 51. It can be done.

-Other embodiments-
In the present embodiment, the case where the outlet pressure recognition means, the negative pressure determination means, the valve opening / closing means, the vehicle state determination means, the stop means, and the restart means are configured as functional units in the engine control ECU 7 has been described. However, at least one of the outlet pressure recognition unit, the negative pressure determination unit, the valve opening / closing unit, the vehicle state determination unit, the stop unit, and the restart unit may be configured by hardware such as an electronic circuit.

  The present invention relates to a compressor provided in an intake passage of an internal combustion engine mounted on a vehicle, a supercharger having a turbine provided in an exhaust passage of the internal combustion engine, an intake passage upstream of the compressor, and the The present invention is applicable to a compressor outlet pressure control device that includes a bypass passage that communicates with an intake passage at the outlet of a compressor, and a bypass valve that opens and closes the bypass passage, and controls the air pressure at the outlet of the compressor.

DESCRIPTION OF SYMBOLS 100 Internal combustion engine system 200 Compressor outlet pressure control apparatus 1 Intake passage 13 Bypass passage 14 Bypass valve 2 Engine 4 Exhaust passage 5 Turbocharger (supercharger)
51 Compressor 511 Impeller 54 Housing 541 Compressor housing 541a Seal plate 55, 56 Bearing 57 Oil discharge system 571 Oil chamber 58 Seal sleeve 581 Oil seal 59 Vortex chamber 61 Flow rate sensor 62 Outlet pressure sensor 63 Intake manifold pressure sensor 64 Throttle opening sensor 7 Engine control ECU
71 Valve open / close control unit 711 Vehicle state determination unit (vehicle state determination means)
712 outlet pressure recognition unit (outlet pressure recognition means)
713 Negative pressure determination unit (negative pressure determination means)
714 Indicator (part of valve opening / closing means)
715 Surging avoidance control unit (part of valve opening / closing means)
72 Engine start / stop control unit 721 Stop unit (stop means)
722 Restart part (restart means)

Claims (9)

A compressor provided in an intake passage of an internal combustion engine mounted on a vehicle; a supercharger having a turbine provided in an exhaust passage of the internal combustion engine; an intake passage upstream of the compressor; and an outlet of the compressor A compressor outlet pressure control device that controls a pneumatic pressure at an outlet of the compressor, comprising a bypass passage communicating with an intake passage; and a bypass valve that opens and closes the bypass passage;
Outlet pressure recognition means for recognizing compressor outlet pressure which is air pressure at the outlet of the compressor;
Negative pressure determining means for determining whether or not the compressor outlet pressure is a negative pressure;
And a valve opening / closing means for opening the bypass valve when the negative pressure determining means determines that the compressor outlet pressure is negative. In the compressor outlet pressure control device according to claim 1,
Vehicle state determination means for determining whether the state of the vehicle is any of a state when the internal combustion engine is started, idling, and decelerated;
The negative pressure determining means is only when the vehicle state determining means determines that the state of the vehicle is one of the state at the start of the internal combustion engine, the idling time, and the deceleration. It is determined whether the said compressor outlet pressure is a negative pressure, The compressor outlet pressure control apparatus characterized by the above-mentioned. In the compressor outlet pressure control device according to claim 2,
The valve opening / closing means may perform surging in the compressor when the vehicle state determining means determines that the state of the vehicle is not any of the start, idling, and deceleration states of the internal combustion engine. A compressor outlet pressure control device that controls the opening and closing of the bypass valve so as to avoid the occurrence of gas. In the compressor outlet pressure control device according to any one of claims 1 to 3,
An outlet pressure sensor for detecting the compressor outlet pressure;
The compressor outlet pressure control device, wherein the outlet pressure recognition means recognizes the compressor outlet pressure based on an output signal from the outlet pressure sensor. In the compressor outlet pressure control device according to any one of claims 1 to 3,
A throttle opening sensor for detecting the throttle opening of the internal combustion engine;
An intake manifold pressure sensor that detects an intake manifold pressure that is an air pressure of an intake manifold of the internal combustion engine;
A flow rate sensor for detecting an air flow rate on the upstream side of the compressor,
The compressor outlet pressure control device, wherein the outlet pressure recognition means estimates the compressor outlet pressure based on the throttle opening, the intake manifold pressure, and the air flow rate. In the compressor outlet pressure control device according to any one of claims 1 to 5,
The compressor outlet pressure control apparatus, wherein the bypass valve is arranged to avoid occurrence of surging in the compressor. In the compressor outlet pressure control device according to any one of claims 1 to 6,
The compressor outlet pressure control device, wherein the bypass valve is an electric valve. In the compressor outlet pressure control device according to any one of claims 1 to 7,
The valve opening / closing means controls opening / closing of the bypass valve to avoid occurrence of surging in the compressor when the negative pressure determination means determines that the compressor outlet pressure is not negative. Compressor outlet pressure control device. In the compressor outlet pressure control device according to any one of claims 1 to 8,
The vehicle is
Stop means for stopping idling of the internal combustion engine when a preset idling stop condition is satisfied;
A compressor outlet comprising: restarting means for restarting the internal combustion engine when a preset restart condition is satisfied after idling of the internal combustion engine is stopped by the stopping means. Pressure control device.

Images