JP6385841B2 - Internal combustion engine negative pressure system - Google Patents

Description

  The present invention relates to a negative pressure system for an internal combustion engine, and more particularly to a negative pressure system that controls a supercharging device using a pressure actuator.

  Conventionally, a negative pressure system using a pressure actuator has been used to open and close a bypass valve of a supercharging device for an internal combustion engine (for example, Patent Document 1). The pressure actuator has a plurality of chambers partitioned by a diaphragm, and is driven by supplying atmospheric pressure or intake pressure in each part of the intake passage to each room via a pressure control valve, opening and closing the bypass valve. To do.

Japanese Utility Model Laid-Open No.2-131033

  Since the negative pressure system according to Patent Document 1 acquires various values of intake pressure from various locations in the intake passage, and selects and supplies these values for each pressure actuator, there is a problem that the piping structure becomes complicated. is there. A solution to this problem is to have a structure that has a negative pressure pump, obtains negative pressure from a negative pressure supply device that supplies negative pressure to the brake booster, and supplies it to each pressure actuator via a pressure control valve Can be considered. In this case, since the pressure source is shared, the piping structure is simplified.

  In this case, if there is a leak in the pipe connecting the pressure actuator and the negative pressure pump, the negative pressure supplied to the brake booster may be reduced, and the operation of the brake booster may be impaired. This problem can be solved by providing a throttle portion in the pipe connecting the negative pressure pump and the pressure actuator to reduce the influence of leakage on the pressure actuator side on the brake booster. In such a negative pressure supply device, there is a case in which leakage from the throttle portion on the side of the pressure actuator is detected based on a state parameter that changes due to the operation of the pressure actuator. In this case, the leakage on the side of the pressure actuator from the restrictor only affects the operation of the pressure actuator, so that an abnormality such as leakage cannot be detected until the pressure actuator is driven. When the type actuator is driven only in a state where the occurrence frequency is relatively low, such as during high-load operation of the internal combustion engine, it takes time to detect a leak.

  In view of the above background, it is an object of the present invention to reduce the influence on a brake booster when a leak occurs in a negative pressure system of an internal combustion engine, and to enable early detection of the leak.

  In order to solve the above problems, the present invention is a negative pressure system (100) of an internal combustion engine (1), which is connected to a negative pressure source (81), the negative pressure source, and a brake booster (86). ) Connected to the main passage (84), a first branch passage (87A) branched from the main passage, a plurality of second branch passages (87B, 87C) branched from the first branch passage, and the first A plurality of pressures connected to each of the second branch passages to control the supercharger (12) and at least one sub-passage (87) provided with a throttle (97) provided in the branch passages Actuators (32, 66) and a plurality of pressure control valves (91, 94) provided in each of the second branch passages for controlling the supply of negative pressure to the pressure actuators. In each of the passages, the internal combustion engine It said pressure control valve for supplying a negative pressure to the pressure actuator when the load range operating state (91), characterized in that it comprises at least one.

  According to this configuration, even if a pressure leak occurs on the pressure control valve side of the throttle portion of the sub-passage, the pressure drop in the main passage is suppressed, and the influence on the operation of the brake booster is reduced. In addition, since the throttle portion is provided in the first branch passage of the sub-passage, if there is a pressure leak in the portion of the sub-passage between the throttle portion and the pressure control valve, it is connected to any of the second branch passages The pressure-type actuator thus made cannot receive the negative pressure and becomes inoperable. The at least one pressure-type actuator connected to the sub-passage should operate in a low-load operation state that occurs in the initial operation of the automobile. A difference occurs between Therefore, the abnormality can be detected early in the initial operation by detecting the difference that occurs.

  In the above invention, each of the sub passages may include at least one pressure control valve (94) for supplying a negative pressure to the pressure actuator when the internal combustion engine is in a high load operation state.

  According to this configuration, the two pressure control valves connected to one sub-passage have different timings for supplying negative pressure to the pressure-type actuators. Insufficient negative pressure supplied to the actuator is prevented.

  In the above invention, the intake pressure sensor (16) for detecting the intake pressure supplied to the cylinder (3) of the internal combustion engine, the intake pressure detected by the intake pressure sensor, and the operating state of the internal combustion engine And an abnormality diagnosing means (99) for detecting an abnormality by comparison with a normal value of the intake pressure set in advance corresponding to the operating state of the pressure control valve.

  According to this configuration, an abnormality in the negative pressure system can be detected based on the intake pressure.

  In the above invention, the supercharging device includes a high pressure stage turbocharger (21) including a high pressure stage turbine (21A) and a high pressure stage compressor (21B), a low pressure stage turbine (22A), and a low pressure stage compressor ( 22B), and a low-pressure stage supercharger (22) connected in series to the high-pressure stage supercharger, and an exhaust pressure supplied to the turbine blade (25) provided in the high-pressure stage turbine is changed. A variable nozzle mechanism (30) to be provided, a high-pressure turbine bypass valve (45) provided in a bypass passage (44) bypassing the high-pressure turbine, and a bypass passage (51) bypassing the low-pressure turbine. The low pressure turbine bypass valve (52) and the high pressure compressor bypass provided in the bypass passage (64) bypassing the high pressure compressor A first pressure actuator (32) that consumes more negative pressure in a low-load operation state than in a high-load operation state so as to drive the variable nozzle mechanism. ), A second pressure actuator (46) having a larger negative pressure consumption in a low load operation state than in a high load operation state, and the low pressure stage turbine bypass valve to drive the high pressure stage turbine bypass valve. In order to drive, the third pressure actuator (54), which consumes a lot of negative pressure in the high load operation state than in the low load operation state, and the high pressure compressor bypass valve to drive the higher pressure compressor bypass valve than in the low load operation state. A fourth pressure actuator (66) that consumes a large amount of negative pressure during a high load operation state, and the sub-passage includes the first pressure actuator and the fourth pressure actuator. The first and the auxiliary passage (87) that 4 connected to a pressure actuator, a second may have a sub-passage (88) connected to said second pressure actuator, and the third pressure actuator.

  According to this configuration, even in a negative pressure system that uses a large number of pressure actuators to control the multistage turbocharger, the effect on the brake booster is reduced when leakage occurs, and early detection of leakage is performed. Can be possible.

  According to the above configuration, in the negative pressure supply device for an internal combustion engine, when leakage occurs, the influence on the brake booster is reduced, and early detection of leakage is possible.

Configuration of a negative pressure supply device for an internal combustion engine according to an embodiment Sectional view of the first actuator Diagram showing the operating state of the internal combustion engine, the negative pressure consumption of each actuator, and the opening of each valve

  Hereinafter, an embodiment in which a negative pressure system according to the present invention is applied to an internal combustion engine equipped with a multistage supercharging device for an automobile will be described in detail with reference to the drawings.

  As shown in FIG. 1, an internal combustion engine 1 of an automobile has an internal combustion engine body 2. The internal combustion engine main body 2 may be a gasoline engine or a diesel engine, and includes a cylinder block, a cylinder head, and the like, and has a cylinder 3 inside.

  In the internal combustion engine body 2, an intake port 4 and an exhaust port 5 that are continuous to the cylinder 3 are formed. The intake port 4 opens on one side of the internal combustion engine body 2, and the exhaust port 5 opens on the other side of the internal combustion engine body 2. An intake device 7 is coupled to one side surface of the internal combustion engine body 2, and an exhaust device 8 is coupled to the other side surface of the internal combustion engine body 2.

  The intake device 7 forms a series of intake passages 11 that communicate with the cylinder 3 together with the intake port 4. The intake device 7 includes, in order from the upstream side, an air inlet, an air cleaner, an intake side portion of the multistage supercharging device 12, an intercooler 13, a throttle valve 14, and an intake manifold 15 in series. It is connected. An intake pressure sensor 16 for detecting the intake pressure of this portion is provided on the downstream side (cylinder 3 side) of the intake side portion of the multistage supercharging device 12 of the intake device 7. In the present embodiment, an intake pressure sensor 16 is provided between the throttle valve 14 and the intake manifold 15.

  The exhaust device 8 forms a series of exhaust passages 17 communicating with the cylinder 3 together with the exhaust port 5. The exhaust passage 17 includes, in order from the upstream side, an exhaust manifold 18, an exhaust side portion of the multistage supercharging device 12, a catalytic converter, a muffler, and an exhaust outlet, and is connected to the exhaust port 5 in the exhaust manifold 18.

  The multi-stage supercharging device 12 includes a high-pressure stage supercharging device 21 and a low-pressure stage supercharging device 22, and constitutes a sequential turbocharger system. The high-pressure stage supercharger 21 has a high-pressure stage turbine 21A and a high-pressure stage compressor 21B, and the low-pressure stage supercharger 22 has a low-pressure stage turbine 22A and a low-pressure stage compressor 22B.

  The high-pressure stage supercharging device 21 includes a high-pressure stage turbine blade 25 and a high-pressure stage compressor blade 26 that are coaxially and integrally connected by a high-pressure stage shaft 24, and a high-pressure stage turbine housing 27 that houses the high-pressure stage turbine blade 25. A high-pressure stage compressor housing 28 that accommodates the high-pressure stage compressor blade 26, and a high-pressure stage bearing housing 29 that connects the high-pressure stage turbine housing 27 and the high-pressure stage compressor housing 28 and rotatably supports the high-pressure stage shaft 24. ing.

  The high-pressure stage supercharging device 21 is a variable nozzle turbocharger (VNT) having a variable nozzle mechanism 30 in a high-pressure stage turbine housing 27. The variable nozzle mechanism 30 includes a plurality of variable nozzle vanes 30A that are rotatably supported by the high-pressure turbine housing 27, and link members 30B that are coupled to the variable nozzle vanes 30A. The plurality of variable nozzle vanes 30 </ b> A are arranged on a circumference centered on the axis of the high-pressure stage shaft 24, each axis of rotation is parallel to the axis of the high-pressure stage shaft 24, and the tip side is radially inward of the high-pressure stage turbine housing 27. It is arranged to face. The link member 30 </ b> B is formed in, for example, an annular shape, and is disposed coaxially with the axis of the high-pressure stage shaft 24. When the link member 30B is displaced (rotated), the direction of each variable nozzle vane 30A changes, and the flow passage cross-sectional area of the exhaust gas formed between the variable nozzle vanes changes. For example, the variable nozzle vane 30A increases the exhaust pressure (exhaust flow velocity) to increase the supercharging efficiency by narrowing (closing) the flow path cross-sectional area when the engine speed is low, and the variable nozzle vane 30A flows when the engine speed is high. By increasing (opening) the cross-sectional area of the road, the exhaust pressure (exhaust flow rate) is lowered to reduce the exhaust resistance. The link member 30B is driven by the first actuator 32 (VNT actuator). Since the variable nozzle mechanism 30 is a kind of valve that controls the exhaust, it may be referred to as the valve 30 in the following description.

  The low-pressure stage supercharging device 22 includes a low-pressure stage turbine blade 34 and a low-pressure stage compressor blade 35 that are coaxially and integrally connected by a low-pressure stage shaft 33, and a low-pressure stage turbine housing 36 that houses the low-pressure stage turbine blade 34. A low-pressure stage compressor housing 37 for housing the low-pressure stage compressor blade 35, and a low-pressure stage bearing housing 38 for connecting the low-pressure stage turbine housing 36 and the low-pressure stage compressor housing 37 and rotatably supporting the low-pressure stage shaft 33. ing. The low-pressure turbine housing 36 has a larger volume than the high-pressure turbine housing 27, and the low-pressure compressor housing 37 has a larger volume than the high-pressure compressor housing 28.

  The exhaust inlet of the high-pressure turbine housing 27 is connected to the exhaust manifold 18 by the first exhaust passage 41. The exhaust outlet of the high-pressure turbine housing 27 is connected to the exhaust inlet of the low-pressure turbine housing 36 by the exhaust connection passage 42. The exhaust outlet of the low-pressure turbine housing 36 is connected to the catalytic converter by the second exhaust passage 43.

  The first exhaust passage 41 and the exhaust connection passage 42 are connected to each other by a turbine bypass passage 44 that bypasses the high-pressure turbine 21A. The turbine bypass passage 44 is provided with a turbine bypass valve 45 (TBV) that opens and closes the turbine bypass passage 44. The turbine bypass valve 45 is a swing valve, and is opened and closed by a second actuator 46 (TBV actuator).

  The exhaust connection passage 42 and the second exhaust passage 43 are connected to each other by a waste gate passage 51 that bypasses the low-pressure turbine 22A. The waste gate passage 51 is provided with a waste gate valve 52 (WGV) that opens and closes the waste gate passage 51. The waste gate valve 52 is a swing valve, and is opened and closed by a third actuator 46 (WGV actuator).

  An intake inlet of the low-pressure compressor housing 37 is connected to an air cleaner by a first intake passage 61. The intake outlet of the low-pressure compressor housing 37 is connected to the intake inlet of the high-pressure compressor housing 28 by an intake connecting passage 62. An intake outlet of the high-pressure compressor housing 28 is connected to the intercooler 13 by a second intake passage 63.

  The intake connection passage 62 and the second intake passage 63 are connected to each other by a compressor bypass passage 64 that bypasses the high-pressure compressor 21B. The compressor bypass passage 64 is provided with a compressor bypass valve 65 (CBV) that opens and closes the compressor bypass passage 64. The compressor bypass valve 65 is a swing valve, and is opened and closed by a fourth actuator 66 (CBV actuator).

  A first actuator 32 that drives the variable nozzle mechanism 30, a second actuator 46 that drives the turbine bypass valve 45, a third actuator 54 that drives the waste gate valve 52, and a fourth actuator 66 that drives the compressor bypass valve 65. Are pressure actuators. Since each actuator 32, 46, 54, 66 has the same configuration, the configuration of the first actuator 32 will be described below, and the description of the other actuators 46, 54, 66 will be omitted.

  As shown in FIG. 2, the first actuator 32 is coupled to the hollow main body 71 having an inner chamber, a partition wall 74 that divides the inner chamber of the main body 71 into an atmospheric pressure chamber 72 and a pressure chamber 73, and the partition wall 74. And a drive shaft 75 provided with a distal end protruding from the main body 71 and connected to the operation target.

  The partition wall 74 can be displaced in the main body 71 and changes the volumes of the atmospheric pressure chamber 72 and the pressure chamber 73 according to the pressure difference between the atmospheric pressure chamber 72 and the pressure chamber 73. In the present embodiment, the partition wall 74 is a flexible diaphragm, and the edge portion is coupled to the main body 71. In another embodiment, the partition wall 74 may be a piston slidably provided in the inner chamber of the main body 71.

  The drive shaft 75 passes through the atmospheric pressure chamber 72 from the base end coupled to the partition wall 74 and protrudes outward from the main body 71. The main body 71 has a breathing hole 77 that is a through hole extending from the outer surface of the main body 71 to the atmospheric pressure chamber 72. The atmospheric pressure chamber 72 is maintained at the atmospheric pressure by the breathing hole 77. The main body 71 has a pressure supply hole 78 which is a through hole extending from the outer surface of the main body 71 to the pressure chamber 73. Each pressure supply hole 78 of each actuator 32, 46, 54, 66 is connected to a negative pressure supply device 80 described below.

  The pressure chamber 73 is provided with a biasing member 79 that biases the partition wall 74 toward the atmospheric pressure chamber 72. In the present embodiment, the urging member 79 is a compression coil spring, and has one end in contact with the pressure chamber 73 side portion of the partition wall 74 and the other end in contact with the portion facing the partition wall 74 of the main body 71. ing. In the initial state where the atmospheric pressure is supplied to the pressure chamber 73 by the urging member 79, the partition wall 74 is located on the atmospheric pressure chamber side, and the drive shaft 75 is in the most protruding position. When negative pressure is supplied to the pressure chamber 73 through the pressure supply hole 78, the partition wall 74 moves against the urging force of the urging member 79 toward the pressure chamber 73, and the protruding length of the drive shaft 75 is small. Become.

  As shown in FIG. 1, the negative pressure supply device 80 has a negative pressure pump 81 as a negative pressure source. The negative pressure pump 81 is a known negative pressure pump (vacuum pump). In this embodiment, the camshaft that rotates in synchronization with the crankshaft of the internal combustion engine body 2 is connected to its own drive shaft, and the rotation of the camshaft is performed. Generates negative pressure under force.

  A main passage 84 is connected to the negative pressure pump 81. The main passage 84 becomes negative pressure by the suction action of the negative pressure pump 81. A brake booster 86 (a booster) is connected to the main passage 84 via a one-way valve 85. The brake booster 86 is a well-known brake booster, and assists the depression of the brake pedal by the occupant using the supplied negative pressure. The one-way valve 85 allows a gas flow from the brake booster 86 side to the main passage 84 side, but prevents a reverse flow.

  A first sub-passage 87 and a second sub-passage 88 are connected to the main passage 84. The first sub-passage 87 includes a first branch passage 87A branched from the main passage 84 and two second branch passages 87B and 87C branched from the first branch passage 87A. Similarly, the second sub-passage 88 has a first branch passage 88A branched from the main passage 84 and two second branch passages 88B and 88C branched from the first branch passage 88A. The end of one second branch passage 87B of the first sub-passage 87 is connected to the pressure supply hole 78 of the first actuator 32, and the end of the other second branch passage 87C is the pressure supply hole 78 of the fourth actuator 66. It is connected to the. The end of one second branch passage 88B of the second sub-passage 88 is connected to the pressure supply hole 78 of the second actuator 46, and the end of the other second branch passage 88C is the pressure supply hole 78 of the third actuator 54. It is connected to the.

  A first pressure control valve 91 is provided in the second branch passage 87B, a second pressure control valve 92 is provided in the second branch passage 88B, and a third pressure control valve 93 is provided in the second branch passage 88C. A fourth pressure control valve 94 is provided in the second branch passage 87C. The first to third pressure control valves 91 to 93 are supplied with the original pressure (negative pressure) and the atmospheric pressure supplied from the main passage 84 side, and are adjusted to an arbitrary value between the original pressure and the atmospheric pressure. EVRV (Electric Vacuum Regulating Valve, or linear solenoid valve) that supplies the output pressure to the actuators 32, 46, and 54 as outputs. The fourth pressure control valve 94 receives a source pressure (negative pressure) and atmospheric pressure supplied from the main passage 84 side, and supplies a source pressure or atmospheric pressure to the fourth actuator 66 side. It is. Each pressure control valve 91-94 is controlled by ECU95, and supplies the pressure according to instruction | command to each actuator 32,46,54,66. The ECU 95 generates a command signal to the pressure control valves 91 to 94 in accordance with the operating state of the internal combustion engine 1 as will be described later.

  When the atmospheric pressure is supplied from the first to fourth pressure control valves 91 to 94, the actuator 32, 46, 54, 66 has the maximum protrusion length of the drive shaft 75, and the first to fourth pressures. When negative pressure is supplied from the control valves 91 to 94, the protruding length of the drive shaft 75 is reduced. The initial state of the actuators 32, 46, 54, and 66 is when the projecting length of the drive shaft 75 is maximum, and the most driven state is when the projecting length is minimum. Since the first to third pressure control valves 91 to 93 can adjust the magnitude of the negative pressure supplied to the first to third actuators 32, 46, and 54, the first to third actuators 32, 46, and 54 can be adjusted. Can be in any driving state between the initial state and the most driven state. On the other hand, since the fourth pressure control valves 91 to 93 have only two pressures that can be supplied to the fourth actuator 66, the original pressure and the atmospheric pressure, the fourth actuator 66 has two states, an initial state and a most driven state. Can be.

  In the variable nozzle mechanism 30, the flow path cross-sectional area between the variable nozzle vanes 30A is maximized when the first actuator 32 is in the initial state, and the flow between the variable nozzle vanes 30A is when the first actuator 32 is in the most driven state. Road cross-sectional area is minimized. The turbine bypass valve 45 is fully opened when the second actuator 46 is in the initial state, and is fully closed when the second actuator 46 is in the most driven state. The waste gate valve 52 is fully closed when the third actuator 54 is in the initial state, and is fully opened when the second actuator 54 is in the most driven state. The compressor bypass valve 65 is fully closed when the fourth actuator 66 is in the initial state, and is fully opened when the fourth actuator 66 is in the most driven state.

  FIG. 3 is a diagram showing the operating state of the internal combustion engine 1, the negative pressure consumption of each actuator 32, 46, 54, 66, and the opening of each valve 30, 45, 52, 65. As shown in FIG. 3, the variable nozzle mechanism 30 reduces the opening degree of the internal combustion engine 1 with a low engine rotational speed in a low-load operation state, increases the opening degree as the engine rotational speed increases, and increases the engine rotational speed. When the internal combustion engine 1 is in a high load operation state, the opening is fully opened. In a low load operation state where the exhaust pressure supplied to the multi-stage turbocharger 12 is low due to the operation of the variable nozzle mechanism 30, the flow pressure between the variable nozzle vanes 30A is narrowed and the exhaust pressure supplied to the high-pressure turbine blade 25 is reduced. In a high-load operation state where the exhaust pressure increases and the exhaust pressure is high, the flow path between the variable nozzle vanes 30A is opened, and the exhaust pressure supplied to the high-pressure stage turbine blade 25 decreases. In order to operate the variable nozzle mechanism 30, the first actuator 32 increases the negative pressure consumption in the low load operation state and decreases the negative pressure consumption in the high load operation state.

  The turbine bypass valve 45 is fully closed when the internal combustion engine 1 is in a low-load operation state, is increased according to the increase in engine speed, and is fully opened when the internal combustion engine 1 is in a high-load operation state. To do. By the operation of the turbine bypass valve 45, in the low load operation state where the exhaust pressure is low, the turbine bypass passage 44 is closed and the entire amount of exhaust passes through the high pressure turbine 21A. Thereafter, when the operating state changes to a high load, the turbine bypass passage 44 is opened by the turbine bypass valve 45, and most of the exhaust gas bypasses the high-pressure turbine 21A and flows directly to the low-pressure turbine 22A. Thereby, the low pressure stage supercharging device 22 is used rather than the high pressure stage supercharging device 21 in a state where the exhaust pressure is high. Since the turbine bypass valve 45 is fully open in the initial state, the second actuator 46 operates the turbine bypass valve 45, so that the negative pressure consumption increases in the low load operation state and the negative pressure in the high load operation state. Consumption is reduced.

  The waste gate valve 52 fully closes when the internal combustion engine 1 is in a low-load operation state, and increases the opening as the engine speed increases. By the operation of the waste gate valve 52, in a low load operation state where the exhaust pressure is low, the waste gate passage 51 is closed and the entire amount of exhaust passes through the low pressure turbine 22A. Thereafter, when the operating state changes to a high load, the waste gate passage 51 is opened by the waste gate valve 52, and a part of the exhaust gas bypasses the low pressure turbine 22A and flows downstream. As a result, it is possible to control the supercharging pressure and to prevent the low pressure stage supercharging device 22 from over-rotating. Since the waste gate valve 52 is fully closed in the initial state, the third actuator 54 operates the waste gate valve 52. Therefore, the negative pressure consumption is reduced in the low load operation state, and the third actuator 54 is negative in the high load operation state. Pressure consumption increases.

  The compressor bypass valve 65 fully opens when the internal combustion engine 1 is in a low load operation state, and fully opens when the internal combustion engine 1 is in a high load operation state. Due to the operation of the compressor bypass valve 65, the compressor bypass passage 64 is closed in the low load operation state, and the entire amount of the intake air passes through the high-pressure compressor 21B. Flows around the high-pressure compressor 21B. This prevents the high-pressure compressor 21B from becoming an intake resistance. Since the compressor bypass valve 65 is fully closed in the initial state, the fourth actuator 66 operates the compressor bypass valve 65. Therefore, the negative pressure consumption is reduced in the low load operation state, and the fourth actuator 66 is negative in the high load operation state. Pressure consumption increases.

  The first branch passages 87A and 88A of the first and second sub passages 87 and 88 are provided with throttle portions 97, respectively. The throttle portion 97 has an inner diameter that is smaller than the inner diameter of the first branch passages 87A, 88A. The throttle part 97 may be formed integrally with the pipe member forming the first branch passages 87A and 88A, or may be formed by incorporating a part formed separately from the pipe member into the pipe member. .

  When the second branch passages 87B, 87C, 88B, and 88C are damaged and become atmospheric pressure than the throttle portions 97 of the sub passages 87 and 88, the throttle portion 97 is more negative on the main passage 84 side than the throttle portion 97. It is provided for the purpose of reducing the effect on pressure. The inner diameter of the throttle portion 97 is preferably set so that the main passage side of each of the sub passages 87 and 88 is maintained at a pressure higher than the pressure that enables the brake booster 86 to operate. Further, the inner diameter of the throttle portion 97 may be set in consideration of the response time of each actuator 32, 46, 54, 66.

  As described above, the negative pressure system 100 for controlling the multi-stage supercharging device 12 of the internal combustion engine 1 includes the actuators 32, 46, 54, 66, the negative pressure pump 81, the main passage 84, the first and the second. The auxiliary passages 87 and 88 and the negative pressure supply device 80 including the first to fourth pressure control valves 91 to 94 are configured.

  The ECU 95 has an abnormality diagnosis unit 99 that detects an abnormality of the negative pressure supply device 80. The abnormality diagnosis unit 99 has a map of normal values of intake pressure set in advance according to the state quantity of the internal combustion engine 1. The state quantity of the internal combustion engine 1 includes engine speed, fuel injection quantity, accelerator pedal depression quantity, vehicle speed, and the like. In the present embodiment, the engine speed and the fuel injection amount are adopted as the state quantities, and the normal value of the intake pressure is set for these. Since each valve 30, 45, 52, 65 is controlled according to the state quantity of the internal combustion engine 1, the map of the normal value of the intake pressure considers the operation of each valve 30, 45, 52, 65. It has become.

  The abnormality diagnosis unit 99 obtains a normal value of the intake pressure based on the state quantity of the internal combustion engine 1 with reference to the map, and compares the normal value of the intake pressure with the intake pressure detected by the intake pressure sensor 16. The abnormality of the negative pressure supply device 80 is detected. For example, the abnormality diagnosis unit 99 determines that an abnormality has occurred when the difference between the normal value of the intake pressure and the actual intake pressure is equal to or greater than a predetermined value. This determination method is based on a predetermined value between the normal value of the intake pressure and the actual intake pressure when any of the valves 30, 45, 52, 65 that should normally be operated does not operate due to pressure leakage or sticking. This is based on the fact that a difference greater than the value occurs.

  The abnormality diagnosing unit 99 includes the abnormality in the main passage 84, the abnormality in the portion on the main passage side of the first and fourth pressure control valves 91 and 94 in the first sub passage 87, the second, regardless of the operating state of the internal combustion engine 1. It is possible to detect an abnormality in the main passage side portion of the sub passage 88 relative to the second and third pressure control valves 92 and 93. Further, the abnormality diagnosis unit 99 detects an abnormality in the first pressure control valve 91 between the first pressure control valve 91 and the first actuator 32 in the first sub passage 87 when the operating state of the internal combustion engine 1 is in a low load region. , The first actuator 32, the variable nozzle mechanism 30, the second pressure control valve 92, the second sub-passage 88 between the second pressure control valve 92 and the second actuator 46. , The second actuator 46 abnormality, and the turbine bypass valve 45 abnormality can be further detected. Further, the abnormality diagnosis unit 99 detects an abnormality in the fourth pressure control valve 94 between the fourth pressure control valve 94 and the fourth actuator 66 in the first sub passage 87 when the operating state of the internal combustion engine 1 is in a high load region. , Part of the fourth actuator 66, part of the compressor bypass valve 65, part of the third pressure control valve 93, part of the second sub-passage 88 between the third pressure control valve 93 and the third actuator 54. , The third actuator 54 abnormality, and the waste gate valve 52 abnormality can be further detected. Here, the abnormality of each passage includes damage accompanied by pressure leakage, and the abnormality of each valve and each pressure control valve includes malfunction caused by pressure leakage, malfunction due to sticking, and the like.

  The effect of the negative pressure system 100 according to the embodiment configured as described above will be described. In the negative pressure system 100, since the throttle portion 97 is provided in the first branch passages 87 </ b> A and 88 </ b> A of the first and second sub passages 87 and 88, the second branch is more than the throttle portion 97 of each sub passage 87 and 88. Even if a pressure leak occurs on the passage side, the pressure drop in the main passage 84 is suppressed, and the influence on the operation of the brake booster 86 is reduced.

  Further, since the throttle portion 97 is provided in the first branch passage 87 </ b> A of the first sub-passage 87, pressure is applied to the portion of the sub-passage 87 between the throttle portion 97 and the first and fourth pressure control valves 91 and 94. When leakage occurs, neither of the first and fourth actuators 32 and 66 can be supplied with negative pressure and become inoperable. And since the 1st pressure type actuator operates in the low load operation state generated at the beginning of driving of a car, a difference arises between the intake pressure assumed in the initial operation and the actual intake pressure, Detected by the abnormality diagnosis unit 99. Therefore, an abnormality can be detected early in the initial stage of operation. If only the third actuator 54 and the fourth actuator 66 that consume negative pressure during the post-load operation state are connected to the first sub-passage 87, in the initial operation of the low-load operation state, A pressure leak cannot be detected by the abnormality diagnosis unit 99 in a portion between the throttle unit 97 and the first and fourth pressure control valves 91 and 94. The second sub passage 88 has the same effect as the first sub passage 87.

  The first and fourth pressure control valves 91 and 94 connected to the first sub-passage 87 have different timings for supplying negative pressure to the actuators 32 and 66. Therefore, the first branch passage 87A has a throttle portion 97. In addition, it is possible to prevent the negative pressure supplied to the actuators 32 and 66 from being insufficient. The second sub passage 88 has the same effect as the first sub passage 87.

  When the internal combustion engine 1 is in a low load operation state, the first and second pressure control valves 91 and 92 that supply negative pressure are distributed and arranged in the first and second auxiliary passages 87 and 88. Even if the portion 97 is present, it is possible to prevent the negative pressure supplied to the actuators 32 and 46 from being insufficient. The third and fourth pressure control valves 93 and 94 have the same effect.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above-described embodiment, the example of the negative pressure system 100 including the two sub passages 87 and 88 is shown. However, the number of the sub passages may be an arbitrary number depending on the number of actuators. Further, the number of second branch passages provided in the sub passages 87 and 88 may be an arbitrary number of 2 or more.

1: Internal combustion engine 12: Multi-stage turbocharger 16: Intake pressure sensor 21: High-pressure stage turbocharger 21A: High-pressure stage turbine 21B: High-pressure stage compressor 22: Low-pressure stage turbocharger 22A: Low-pressure stage turbine 22B: Low-pressure stage compressor 30 : Variable nozzle mechanism 32: First actuator 44: Turbine bypass passage 45: Turbine bypass valve 46: Second actuator 51: Waste gate passage 52: Waste gate valve 54: Third actuator 64: Compressor bypass passage 65: Compressor bypass valve 66 : Fourth actuator 80: Negative pressure supply device 81: Negative pressure pump (negative pressure source)
92: Second pressure control valve 84: Main passage 86: Brake boosters 87, 88: Sub passages 87A, 88A: First branch passages 87B, 87C, 88B, 88C: Second branch passages 91-94: Pressure control valve 95: ECU
97: Restriction part 99: Abnormality diagnosis part 100: Negative pressure system

Claims (4)

A negative pressure system for an internal combustion engine,
A negative pressure source,
A main passage connected to the negative pressure source and connected to a brake booster;
A first branch passage branched from the main passage, a plurality of second branch passages branched from the first branch passage, and at least one sub-passage provided with a throttle portion provided in the first branch passage;
A plurality of pressure actuators connected to each of the second branch passages to control the supercharging device;
A plurality of pressure control valves provided in each of the second branch passages for controlling supply of negative pressure to the pressure actuator;
Each of the sub passages includes at least one pressure control valve for supplying a negative pressure to the pressure actuator when the internal combustion engine is in a low load region operation state.   2. The internal combustion engine according to claim 1, wherein each of the sub passages includes at least one of the pressure control valves for supplying a negative pressure to the pressure actuator when the internal combustion engine is in a high load operation state. Negative pressure system. An intake pressure sensor for detecting an intake pressure supplied to a cylinder of the internal combustion engine;
Abnormality diagnosis means for detecting an abnormality by comparing the intake pressure detected by the intake pressure sensor with a normal value of the intake pressure set in advance corresponding to the operating state of the internal combustion engine and the operating state of the pressure control valve The negative pressure system for an internal combustion engine according to claim 1, further comprising: The supercharger comprises a high-pressure stage turbocharger comprising a high-pressure stage turbine and a high-pressure stage compressor, and a low-pressure stage supercharger comprising a low-pressure stage turbine and a low-pressure stage compressor and connected in series to the high-pressure stage supercharger. A variable nozzle mechanism that is provided in the high-pressure turbine and changes exhaust pressure supplied to the turbine blades, a high-pressure turbine bypass valve that is provided in a bypass passage that bypasses the high-pressure turbine, and the low-pressure A low pressure turbine bypass valve provided in a bypass passage that bypasses the stage turbine, and a high pressure compressor bypass valve provided in a bypass passage that bypasses the high pressure compressor,
In order to drive the variable nozzle mechanism, the pressure actuator drives the first pressure actuator that consumes a larger amount of negative pressure in the low load operation state than in the high load operation state, and the high pressure turbine bypass valve. Therefore, in order to drive the second pressure actuator, which consumes a lot of negative pressure in a low load operation state than in a high load operation state, and the low pressure turbine bypass valve, a higher load operation state than in a low load operation state. A third pressure actuator that sometimes consumes a negative pressure, and a fourth pressure actuator that consumes a lot of negative pressure in a high load operation state rather than a low load operation state to drive the high pressure compressor bypass valve And
The sub passage includes a first sub passage connected to the first pressure actuator and the fourth pressure actuator, a second sub passage connected to the second pressure actuator and the third pressure actuator, and The negative pressure system for an internal combustion engine according to any one of claims 1 to 3, characterized by comprising:

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