JP2012241609A - Fluid control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid control system capable of detecting an open failure of a thermostat at least on the side low in a valve opening temperature.SOLUTION: A fluid supply system includes the thermostats 18, 19 arranged in branch pathways PB1, PB2, valve mechanisms V1, V2 arranged in sections SG1, SG2, and an ECU 30 executing a first control for controlling the second valve mechanism V2 so as to limit the circulation of a coolant when a temperature thw falls below a first target temperature α and exceeds a first threshold α' in a condition in which the limitation of the circulation of the coolant is released by the valve mechanisms V1, V2, and moreover, determining that the second thermostat 19 has the open failure in which the valve is kept open when the temperature thw rises after execution of the first control.

Description

  The present invention relates to a fluid control system.

  As a technique for controlling a fluid such as engine coolant, a technique that is considered to be related to the present invention in that it includes a high water temperature control valve and a low water temperature control valve is disclosed in Patent Document 1, for example. Further, for example, Patent Document 2 discloses a technique that is considered to be related to the present invention in terms of diagnosing an open fixing failure of a thermostat. In addition, for example, Patent Document 3 discloses a technique that is considered to be related to the present invention in terms of configuration.

JP 2002-138836 A JP 2007-9846 A Japanese Patent Laid-Open No. 10-77837

  For example, a thermostat and a valve mechanism can be provided as follows to enable supplying a relatively high-temperature fluid to a fluid supply target and supplying a relatively low-temperature fluid.

  That is, of the first and second branch paths that merge after branching, the first thermostat is provided in the first branch path, and the valve opening temperature is set lower in the second branch path than in the first thermostat. A second thermostat can be provided. In addition, the first valve is included in the first portion that is the portion after the first and second branch paths merge among the fluid supply paths that include the first and second branch paths and that supply the fluid to the supply target. In addition to providing a mechanism, a second valve mechanism can be provided in a second portion of the second branch path, which is a portion downstream of the second thermostat.

  In this case, in a state where the flow control of the fluid by the first thermostat is enabled by the first valve mechanism, by switching the enable / disable of the flow control of the fluid by the second thermostat by the second valve mechanism, Fluid flow control by a thermostat can be made possible.

  Specifically, the fluid flow control by the first thermostat can be enabled by disabling the fluid flow control by the second thermostat by the second valve mechanism. Also, by enabling the fluid flow control by the second thermostat by the second valve mechanism, the fluid flow control by the second thermostat can be enabled. This is because the first thermostat is closed when the fluid temperature falls below the valve opening temperature of the first thermostat even in a state where the flow control of the fluid by the first thermostat is still effective.

  In this case, by enabling the fluid flow control by the first thermostat, it is possible to perform a high liquid temperature control that controls the temperature of the fluid to a relatively high temperature. In addition, by enabling fluid flow control by the second thermostat, it is possible to perform low liquid temperature control that controls the temperature of the fluid to a relatively low temperature.

  However, in this case, even when an open failure occurs in which one of the first and second thermostats remains open, it is not easy to detect the failure. This is because, for example, the following situation may occur when fluid flow control by the second thermostat is enabled.

  That is, for example, the first thermostat has an open failure and the second thermostat is normally closed, and the first thermostat is normally closed and the second thermostat is open. This is because a failure state may occur. This is because there may be no great difference in the control temperature of the fluid between these states. For this reason, in this case, for example, when both the first and second thermostats are normal, the control temperature of the fluid is estimated and compared with the actual control temperature. It is difficult to determine whether or not

  In view of the above-mentioned problems, the present invention switches the fluid flow control by the thermostat on the side where the valve opening temperature is low among the thermostats provided in each of the branch paths that merge after branching, so that the fluid by each thermostat It is an object of the present invention to provide a fluid control system capable of detecting an open failure of a thermostat on the side having a low valve opening temperature when it is possible to perform the flow control.

  The present invention provides a first thermostat provided in the first branch path and a first thermostat provided in the second branch path among the first and second branch paths that merge after branching. A second thermostat having a lower valve opening temperature and the first and second branch paths, and the first and second branches of the fluid supply paths for supplying fluid to the supply target The first valve mechanism provided in the first part that is the part after the path merge, and the second part that is downstream of the second thermostat among the second branch paths. In the state where the second valve mechanism and the first and second valve mechanisms are released from the fluid flow restriction, the control temperature of the fluid is at least a temperature to be controlled according to the state. Below the target temperature of 1 And when the temperature exceeds a first predetermined value that is lower by a predetermined degree than the first target temperature, the first valve mechanism that controls the second valve mechanism to restrict the flow of fluid is controlled. A controller that performs control, and an open failure that causes the second thermostat to remain open when the control temperature of the fluid rises after the controller performs the first control. It is a fluid control system provided with the judgment part which judges that it exists.

  In the first portion, the first thermostat is closed in the first portion by operating in a mechanically interlocked manner with a bypass path that bypasses the first valve mechanism and the first thermostat. A bypass valve that communicates with the bypass path and shuts off the bypass path when the first thermostat is open, and the control unit performs the first control. When the control temperature of the fluid does not rise, the first valve mechanism is controlled to further restrict the fluid flow, and the second valve mechanism is controlled to release the fluid flow restriction. After the control unit performs the second control, the control temperature of the fluid restricts the flow of the fluid by the first valve mechanism, and the second valve machine Is lower than a second predetermined value that is lower than a second target temperature, which is a temperature to be controlled according to a state in which the fluid circulation restriction is released, by a predetermined degree, the first It can be set as the structure which judges that it is in the open failure which remains in the state in which the thermostat of the valve is still open.

  The present invention relates to an estimation unit that estimates a control temperature of a fluid when the first and second thermostats are normal, and after the control unit performs the second control, the control temperature of the fluid is the second control temperature. And when the degree of deviation between the fluid control temperature and the estimated control temperature, which is the control temperature estimated by the estimation unit, exceeds a predetermined level, the determination unit Of the second thermostats, the first thermostat may be determined to have an open failure in which the valve remains open.

  According to the present invention, after the branching, among the thermostats provided in the branch paths to be joined, the fluid circulation control by the thermostat having the lower valve opening temperature is switched between valid and invalid so that the fluid circulation by each thermostat is performed. When the control can be performed, it is possible to detect at least an open failure of the thermostat on the side where the valve opening temperature is low.

It is a schematic block diagram of an engine cooling circuit. It is a schematic block diagram of a rotary valve. Fig.3 (a) is a figure which shows a rotary valve body by a side view. FIG.3 (b) is a figure which shows a rotary valve body by the arrow A shown to Fig.3 (a). Fig.4 (a) is a figure which shows a rotary valve body in the AA cross section shown to Fig.3 (a). FIG.4 (b) is a figure which shows a rotary valve body in the BB cross section shown to Fig.3 (a). FIG.4 (c) is a figure which shows a rotary valve body in CC cross section shown to Fig.3 (a). It is a figure which shows a fluid supply path | route. It is a schematic block diagram of ECU. It is a figure which shows control operation with a flowchart.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an engine cooling circuit (hereinafter referred to as a cooling circuit) 100. The cooling circuit 100 includes a water pump (hereinafter referred to as W / P) 1, an engine 2, an oil cooler 3, a heater 4, an ATF (Automatic Transmission Fluid) warmer 5, a radiator 6, and an electronic control throttle 7. The rotary valve 10 is provided. The cooling circuit 100 is mounted on a vehicle (not shown).

  W / P1 circulates the coolant of the engine 2 that is a fluid. W / P 1 is a mechanical pump that is driven by the output of the engine 2. W / P1 may be an electrically driven pump. The coolant discharged from the W / P 1 flows into the engine 2 and the electronic control throttle 7 through the rotary valve 10. When flowing into the engine 2, the coolant flows out of the rotary valve 10 through the outlet portions Out 1 and Out 2. Further, when flowing into the electronic control throttle 7, the coolant flows out of the rotary valve 10 via the outlet portion OutA.

  The engine 2 includes a cylinder block 2a and a cylinder head 2b. The engine 2 is provided with the following cooling passages. That is, the coolant flowing in from the outlet portion Out1 is circulated in the order of the cylinder block 2a and the cylinder head 2b, and the coolant flowing in from the outlet portion Out2 is circulated to the cylinder head 2b, and these are further merged by the cylinder head 2b. After that, a cooling passage is provided through which the combined coolant flows out from the cylinder head 2b.

  Among the coolant that has circulated through the engine 2, a part of the coolant flows through the oil cooler 3, the heater 4, and the ATF warmer 5, and the remaining coolant flows through the radiator 6. The oil cooler 3 exchanges heat between the lubricating oil of the engine 2 and the coolant to cool the lubricating oil. The heater 4 exchanges heat between the air and the coolant to heat the air. The heated air is used for heating the passenger compartment. The ATF warmer 5 exchanges heat between the ATF and the coolant to heat the ATF. The radiator 6 is a cooler, and cools the coolant by exchanging heat between the air and the coolant.

  The coolant that has passed through the oil cooler 3, the heater 4, and the ATF warmer 5 returns to the W / P 1 through the rotary valve 10. At this time, the coolant flows into the rotary valve 10 through the inlet portion In1. In addition, the coolant flowing through the radiator 6 flows into the rotary valve 10 through the inlet portion In2. A distribution path for distributing the oil cooler 3, the heater 4 and the ATF warmer 5 is a first radiator bypass path P <b> 11 that bypasses the radiator 6.

  The coolant flowing into the electronic control throttle 7 flows through the electronic control throttle 7 and then merges with the first radiator bypass path P11. A coolant can be circulated through the electronic control throttle 7 in order to prevent the occurrence of malfunction due to freezing. A distribution path for distributing the electronic control throttle 7 is an engine bypass path P2 for bypassing the engine 2.

  Further, in the cooling circuit 100, a part of the coolant flowing through the engine 2 flows into the rotary valve 10 via the inlet portion In3. This distribution path is a second radiator bypass path P12 that bypasses the radiator 6. Therefore, the coolant flowing through the first radiator bypass path P11 flows into the rotary valve 10 through the inlet portion In1. In addition, the coolant flowing through the second radiator bypass path P12 flows through the inlet portion In3.

  FIG. 2 is a schematic configuration diagram of the rotary valve 10. In FIG. 2, W / P 1 is also shown together with the rotary valve 10. As shown in FIGS. 1 and 2, the rotary valve 10 includes a first passage portion 11, a second passage portion 12, a rotary valve body 13, a drive portion 14, a valve body bypass passage portion 15, 1 bypass valve 16, detector 17, first thermostat 18, second thermostat 19, second bypass valve 20, and check valve 21. In addition, it includes inlet portions In1, In2, and In3 and outlet portions Out1, Out2, and OutA. In FIG. 2, the check valve 21 is not shown for the sake of illustration.

  The 1st channel | path part 11 is provided between the coolant outlet part of W / P1, and the engine 2, and distribute | circulates a coolant. The 2nd channel | path part 12 is provided between the coolant inlet_port | entrance part of W / P1, and the radiator 6, and distribute | circulates a coolant. The passage portions 11 and 12 are arranged side by side. The passage portions 11 and 12 are connected to W / P1 at the ends in a state where they are arranged side by side. The first passage portion 11 is connected to the coolant outlet portion of the pump 1, and the second passage portion 12 is connected to the coolant inlet portion of the pump 1. In the first passage portion 11, the W / P1 side is the upstream side, and in the second passage portion 12, the W / P1 side is the downstream side.

  The first passage portion 11 communicates with the outlet portions Out1 and Out2 on the downstream side of the rotary valve body 13, and communicates with the outlet portion OutA on the upstream side of the rotary valve body 13. Therefore, the outlet portions Out1 and Out2 allow the coolant to flow out from the downstream portion of the rotary valve body 13 in the first passage portion 11. Further, the outlet portion OutA causes the coolant to flow out from the upstream portion of the rotary valve body 13 in the first passage portion 11.

  The second passage portion 12 communicates with the inlet portion In1 on the upstream side and the downstream side of the rotary valve body 13. Accordingly, the inlet portion In1 allows the coolant to flow into the upstream portion and the downstream portion of the second passage portion 12 with respect to the rotary valve body 13. For convenience of illustration, the state in which the inlet portion In1 and the upstream side and the downstream side of the second passage portion 12 communicate with each other is not shown in FIG.

  The second passage portion 12 communicates with the inlet portion In2 on the upstream side and the downstream side of the rotary valve body 13. Therefore, the inlet portion In <b> 2 allows the coolant to flow through the second passage portion 12 to the upstream portion and the downstream portion of the rotary valve body 13. In this respect, the second passage portion 12 includes a first communication portion B1 that communicates a portion downstream of the rotary valve body 13 and the inlet portion In2, and a portion upstream of the rotary valve body 13 and the inlet portion In2. And a second communication part B2 that communicates with each other. The second passage portion 12 further communicates with the inlet portion In3 on the upstream side of the rotary valve body 13.

  The rotary valve body 13 is provided so as to be interposed between the first passage portion 11 and the second passage portion 12. The rotary valve body 13 changes the circulation of the coolant flowing through the first passage portion 11 and the circulation of the coolant flowing through the second passage portion 12 by a rotating operation. The rotary valve body 13 prohibits and permits the circulation of the coolant flowing through the first passage portion 11 and the circulation of the coolant flowing through the second passage portion 12. It can be performed. The drive unit 14 includes an actuator 14 a and a gear box unit 14 b and drives the rotary valve body 13. The actuator 14a is specifically an electric motor.

  The valve body bypass passage portion 15 communicates the upstream portion and the downstream portion of the first passage portion 11 with respect to the rotary valve body 13. The first bypass valve 16 is a differential pressure valve, and in the first passage portion 11, the coolant pressure (upstream pressure) in the upstream portion of the rotary valve body 13 and the downstream of the rotary valve body 13. The flow of the coolant via the valve body bypass passage 15 is restricted and the restriction is released according to the pressure difference with the coolant pressure (downstream pressure) at the side portion (specifically, prohibited or permitted here) )I do.

  Specifically, the first bypass valve 16 is cooled via the valve body bypass passage portion 15 when the magnitude of the differential pressure obtained by subtracting the downstream pressure from the upstream pressure is equal to or less than a predetermined magnitude. The flow of the liquid is prohibited, and the flow of the coolant through the valve body bypass passage portion 15 is permitted when the flow is higher than a predetermined size. The predetermined magnitude can be set larger than the magnitude of the maximum differential pressure obtained in the normal case.

  The first bypass valve 16 is further configured to operate mechanically in conjunction with the first thermostat 18. In this regard, the first thermostat 18 is provided with an operating shaft 18 a connected to the first bypass valve 16 by extending so as to be interposed in the passage portions 11 and 12. The first bypass valve 16 allows the operating shaft 18a to drive the first bypass valve 16 so that the coolant flows through the valve body bypass passage portion 15 with the first thermostat 18 closed. While permitting, the flow of the coolant through the valve body bypass passage portion 15 is prohibited with the first thermostat 18 opened.

  In order to configure the first bypass valve 16 to be a differential pressure valve and to operate mechanically in conjunction with the first thermostat 18, for example, the first bypass valve 16 is opened with a differential pressure. While providing the structure, the entire first bypass valve 16 can be configured to operate mechanically in conjunction with the first thermostat 18.

  The detector 17 is provided with respect to the drive shaft of the actuator 14a. The detector 17 detects the rotation angle of the drive shaft of the actuator 14a. Thus, the phase of the rotary valve body 13 can be detected or estimated. The detection unit 17 may be provided, for example, with respect to the rotation shaft of the rotary valve body 13.

  The first thermostat 18 is provided in the first communication part B1. The second thermostat 19 is provided in the second communication part B2. Therefore, the second passage portion 12 communicates with the inlet portion In2 via the first thermostat 18 on the downstream side of the rotary valve body 13. As a result, it communicates with the radiator 6 via the first thermostat 18 on the downstream side of the rotary valve body 13. The second passage portion 12 communicates with the inlet portion In <b> 2 via the second thermostat 19 on the upstream side of the rotary valve body 13. As a result, the upstream side of the rotary valve body 13 communicates with the radiator 6 via the second thermostat 19.

  The valve opening temperatures of the thermostats 18 and 19 are different from each other. The valve opening temperature of the second thermostat 19 is set lower than the valve opening temperature of the first thermostat 18. In this respect, the first thermostat 18 opens when the temperature of the coolant is higher than the predetermined value A, and closes when the temperature of the coolant is equal to or lower than the predetermined value A. The second thermostat 19 opens when the temperature of the coolant is higher than a predetermined value B, which is smaller than the predetermined value A, and closes when the temperature is lower than the predetermined value B.

  The second bypass valve 20 is provided to communicate and block the inlet portion In3. The second bypass valve 20 is configured to operate mechanically in conjunction with the second thermostat 19. Specifically, the second bypass valve 20 is connected to an operating shaft (not shown) of the second thermostat 19. The second bypass valve 20 allows the coolant to flow through the inlet portion In3 (that is, the second radiator bypass path P12) with the second thermostat 19 closed, and the second thermostat 19 In a state where the valve is opened, the flow of the coolant through the inlet portion In3 is prohibited.

  The check valve 21 controls the flow of the coolant that flows in from the inlet portion In1. Specifically, the check valve 21 permits the flow from the upstream side to the downstream side when the coolant flowing in from the inlet portion In1 flows into the upstream side and the downstream side of the second passage portion 12, and from the downstream side. Distributing upstream is prohibited.

  FIG. 3A is a view showing the rotary valve body 13 in a side view. FIG. 3B is a view showing the rotary valve body 13 as indicated by an arrow A shown in FIG. 4A is an AA cross section shown in FIG. 3A, FIG. 4B is a BB cross section shown in FIG. 3A, and FIG. 4C is FIG. 3A. It is a figure which shows the rotary valve body 13 in CC section shown.

  The rotary valve body 13 includes a first valve body portion R1 disposed in the first passage portion 11, and a second valve body portion R2 disposed in the second passage portion 12. The valve body portions R1 and R2 are both members having a hollow inside. In this respect, the insides of the valve body portions R1 and R2 do not communicate with each other.

  The first valve body R1 is provided with a first opening G1, and the second valve body R2 is provided with a second opening G2. The openings G1 and G2 are provided with different phases. The first opening G1 is a part combining the two opening parts divided by the column, and the second opening G2 is a part combining the three opening parts divided by the column.

  The first opening G <b> 1 can permit the coolant to flow to the engine 2 in a state opened to the upstream side and the downstream side of the first passage portion 11. Further, it is possible to prohibit the circulation of the coolant to the engine 2 in a state where only one of the upstream side and the downstream side of the first passage portion 11 is open. The first opening G <b> 1 is open to the upstream side and the downstream side of the first passage portion 11, and the flow rate of the coolant flowing through the engine 2 can be adjusted according to the phase of the rotary valve body 13.

  The second opening G2 can be allowed to flow through the second opening G2 in a state where the second opening G2 is opened upstream and downstream of the second passage portion 12. In addition, it is possible to prohibit the flow of the coolant through the second opening G2 in a state where only one of the upstream side and the downstream side of the second passage portion 12 is open.

  The second valve body R2 is further provided with a third opening G3. The third opening G3 is provided at a position different from the second opening G2 in the axial direction. The third opening G3 is a second opening when the second opening G2 is located on the downstream side of the second passage portion 12 with the second opening G2 opening on the upstream side and the downstream side of the second passage portion 12. It is provided so as to open downstream of the passage portion 12. On the other hand, when the second opening G2 is open on the upstream side and the downstream side of the second passage portion 12 and is located on the upstream side of the second passage portion 12, the second passage portion 12 It is provided so as not to open upstream.

  Therefore, when the third opening G3 is located on the downstream side of the second passage portion 12, it is possible to allow the coolant to flow through the third opening G3. At this time, the coolant can be allowed to flow through the openings G2 and G3. On the other hand, when the third opening G3 is located on the upstream side of the second passage portion 12, the flow of the coolant through the third opening G3 can be prohibited. At this time, the circulation of the coolant through the second opening G2 out of the openings G2 and G3 can be permitted.

  When the third opening G3 is located on the upstream side of the second passage part 12, the second opening G2 is opened on the upstream side and the downstream side of the second passage part 12, and the rotary valve body The flow rate of the coolant flowing from the upstream side to the downstream side of the second passage portion 12 with the rotary valve body 13 interposed therebetween can be gradually increased or decreased in accordance with the phase 13. In addition, when the third opening G3 is located on the downstream side of the second passage portion 12, the opening portions G2 and G3 are opened to the upstream side and the downstream side of the second passage portion 12, and the rotary valve Depending on the phase of the body 13, the flow rate of the coolant flowing from the upstream side to the downstream side of the second passage portion 12 with the rotary valve body 13 interposed therebetween can be gradually increased or decreased.

  The rotary valve body 13 configured as described above can simultaneously control the circulation of the coolant in the first passage portion 11 and the circulation of the coolant in the second passage portion 12 by a rotating operation.

  Specifically, for example, the rotary valve body 13 cancels the restriction on the flow of the coolant from the upstream side to the downstream side of the first passage portion 11 with the rotary valve body 13 sandwiched by the first valve body portion R1 ( At the same time, the flow of the coolant from the upstream side to the downstream side of the second passage portion 12 with the rotary valve body 13 sandwiched by the second valve body portion R2 is restricted (specifically, permitted here). Can be prohibited here). Further, for example, the restriction on the flow of the coolant from the upstream side to the downstream side of the first passage portion 11 with the rotary valve body 13 sandwiched between the first valve body portion R1 is released (specifically, here permitted) At the same time, the restriction of the flow of the coolant from the upstream side to the downstream side of the second passage portion 12 with the second valve body portion R2 sandwiching the rotary valve body 13 therebetween is released (specifically, here) Allowed).

  1 and 2, the first passage portion 11 communicating with the outlet portion OutA on the upstream side of the rotary valve body 13 is branched to the engine bypass path P2 on the upstream side of the rotary valve body 13. Yes. For this reason, when the rotary valve body 13 prohibits the flow of the coolant to the engine 2 in the first passage portion 11, the rotary valve 10 can flow the coolant to the engine bypass path P2.

  Specifically, the first passage portion 11 can be branched so that the following flow control can be performed according to the phase of the rotary valve body 13. That is, depending on the phase of the rotary valve body 13, it can be branched so that the flow of the coolant to the cylinder block 2 a and the cylinder head 2 b can be prohibited. Further, it is possible to branch so that the flow of the coolant to the cylinder block 2a is prohibited and the flow of the coolant to the cylinder head 2b can be permitted. Furthermore, it can be branched so that the coolant can be allowed to flow to the cylinder block 2a and the cylinder head 2b.

  In order to branch in this way, more specifically, the first passage portion 11 can be branched corresponding to each of different phases of the rotary valve body 13. In FIG. 2, for convenience of illustration, the first passage portion 11 is shown so as to be branched corresponding to the same phase of the rotary valve body 13. In this regard, for example, even when the first passage portion 11 is branched corresponding to the same phase of the rotary valve body 13, the first valve body portion has the same structure as the second valve body portion R2 in the rotary valve body 13. In addition to being applied to R1, the above-described flow control can be enabled by branching the first passage portion 11 in correspondence with the openings G2 and G3. In supplying the coolant to the engine 2, the first passage portion 11 may not be branched on the downstream side of the rotary valve body 13. In this case, for example, the coolant can be supplied to the cylinder block 2a.

  FIG. 5 is a diagram showing the fluid supply path PS. The fluid supply path PS is a path for supplying the coolant to the coolant supply target, that is, the engine 2 to be cooled, and includes branch paths PB1 and PB2 that merge after branching. The fluid supply path PS is a path for supplying the coolant from the radiator 6 to the engine 2. Therefore, the radiator 6 cools the coolant flowing on the upstream side of the branch paths PB1 and PB2. Specifically, the first branch path PB1 corresponds to a path that reaches the downstream side of the second passage portion 12 via the first communication portion B1. Specifically, the second branch path PB2 corresponds to a path that reaches the second communication part B2, the upstream side of the second passage part 12, and the downstream side of the second passage part 12 via the rotary valve 10. ing.

  The thermostat unit T includes a first thermostat 18 on the first branch path PB1 and a second thermostat 19 on the second branch path PB2. The valve unit V includes the first valve mechanism V1 in the first portion SG1 that is a portion after the branch paths PB1 and PB2 merge in the fluid supply path PS, and the second portion of the second branch path PB2. A second valve mechanism V <b> 2 is provided in the second portion SG <b> 2 that is a portion on the downstream side of the thermostat 19. The valve portion V includes the uniaxial rotary valve body 13 disposed in the portions SG1 and SG2, so that the first portion SG1 includes the first valve mechanism V1 and the second portion SG2 includes the second valve mechanism. V2 is provided. The valve body bypass passage portion 15 forms a bypass path that bypasses the first valve mechanism V1 in the first portion SG1.

  In the fluid supply path PS configured in this way, the second thermostat 19 is controlled by the second valve mechanism V2 in a state where the flow control of the coolant by the first thermostat 18 is enabled by the first valve mechanism V1. By disabling the coolant flow control according to the above, the coolant flow control by the first thermostat 18 can be enabled. Further, in a state where the flow control of the coolant by the first thermostat 18 is enabled by the first valve mechanism V1, the flow control of the coolant by the second thermostat 19 is enabled by the second valve mechanism V2. Thus, the flow control of the coolant by the second thermostat 19 can be made possible.

  In other words, in the fluid supply path PS configured in this way, the circulation control of the coolant by the thermostats 18 and 19 can be enabled by switching between the enable and disable of the coolant control by the second thermostat 19. it can. In this case, by enabling the coolant flow control by the first thermostat 18, it is possible to perform high liquid temperature control that controls the temperature of the coolant to a relatively high temperature. Further, by allowing the second thermostat 19 to control the flow of the coolant, it is possible to perform a low liquid temperature control that controls the temperature of the coolant to a relatively low temperature.

  FIG. 6 is a schematic configuration diagram of the ECU 30. The ECU 30 includes a microcomputer including a CPU 31, a ROM 32, a RAM 33, and the like, and input / output circuits 34 and 35. These components are connected to each other via a bus 36. The ECU 30 is electrically connected to a sensor group 40 for detecting the operating state of the detection unit 17 and the engine 2 and the state of the vehicle via an input circuit 34. Further, the actuator 14 a is electrically connected via the output circuit 35.

  The sensor group 40 can detect the rotational speed NE of the engine 2, a sensor that can detect the load of the engine 2, a sensor that detects the temperature thw of the coolant flowing through the engine 2, and a vehicle speed that can be detected. And a sensor for detecting the outside air temperature of the vehicle. The temperature thw is the control temperature of the coolant, and is, for example, the temperature of the coolant in the portion upstream of the first valve mechanism V1 in the first portion SG1. For example, the sensor group 40 may be indirectly connected via a control device that controls the engine 2. Alternatively, the ECU 30 may be a control device that controls the engine 2, for example.

  The ROM 72 is configured to store a program in which various processes executed by the CPU 31 are described, map data, and the like. Various functions are realized in the ECU 30 when the CPU 31 executes processing while using the temporary storage area of the RAM 33 as necessary based on the program stored in the ROM 32. In this regard, in the ECU 30, for example, the following control unit, determination unit, and estimation unit are functionally realized.

  When the control unit is in a state where the valve mechanisms V1 and V2 have released the flow restriction of the coolant (that is, in the state where the low liquid temperature control is performed), the temperature thw is at least lower than the first target temperature α. First, the first control is performed to control the second valve mechanism V2 so as to limit the flow of the coolant. The first target temperature α is a temperature that should be controlled in accordance with the state in which the valve mechanisms V1 and V2 have released the coolant flow restriction.

  In performing the first control, the control unit assumes that the temperature thw is at least lower than the first target temperature α. Specifically, the temperature thw is lower than the first target temperature α, and the first When the temperature exceeds a first threshold value α ′, which is a first predetermined value that is lower by a predetermined degree than the target temperature α, the second valve mechanism V2 is controlled so as to limit the flow of the coolant. . More specifically, when the temperature thw is lower than the fourth threshold value δ and higher than the first threshold value α ′, the second valve mechanism V2 is set so as to restrict the flow of the coolant. Control. The fourth threshold δ can be set to a value lower than the first target temperature α and higher than the first threshold α ′.

  When the temperature thw rises after the control unit performs the first control, the determination unit determines that the second thermostat 19 has an open failure that remains open. Specifically, when the temperature thw exceeds the first threshold value α ′ (specifically, when the temperature thw is equal to or higher than the first threshold value α ′), the second thermostat 19 causes an open failure. Judge that In this regard, the determination unit specifically determines that the second thermostat 19 out of the thermostats 18 and 19 has an open failure. When the temperature thw does not increase, the determination unit determines that the first thermostat 18 has an open failure, the thermostats 18 and 19 both have an open failure, or the thermostats 18 and 19 are both normal.

  The control unit controls the first valve mechanism V1 so as to further restrict the circulation of the cooling liquid when the temperature thw does not increase after performing the first control, and cancels the restriction on the circulation of the cooling liquid. The second control for controlling the second valve mechanism V2 is performed.

  The determination unit further determines that the first thermostat 18 has an open failure when the temperature thw is at least lower than the second target temperature β after the control unit performs the second control. The second target temperature β is a temperature that should be controlled in accordance with the state in which the first valve mechanism V1 restricts the flow of the coolant and the second valve mechanism V2 releases the flow restriction of the coolant. is there.

  The determination unit assumes that the temperature thw is at least lower than the second target temperature β. Specifically, the temperature thw is a second predetermined value whose temperature is lower than the second target temperature β by a predetermined degree. If it is below the threshold value β ′ of 2, it is determined that the first thermostat 18 has an open failure. In this regard, the determination unit specifically determines that both the thermostats 18 and 19 have an open failure. When the temperature thw exceeds the second threshold value β ′ (specifically, when the temperature thw is equal to or higher than the second threshold value β ′ in this case), the determination unit determines that the first thermostat 18 of the thermostats 18 and 19 is open. It is determined that the thermostats 18 and 19 are normal.

  The estimation unit estimates the temperature thw when the thermostats 18 and 19 are normal. Specifically, the estimation unit is configured to change the temperature thw when the flow control state of the valve mechanisms V1 and V2 and the thermostats 18 and 19 are normal and the flow control states of the valve mechanisms V1 and V2 are the same ( For example, the temperature thw is estimated based on the outside air temperature, the usage state of the heater 4, and the load of the engine 2. The estimation unit estimates the control temperature thw, thereby calculating the estimated control temperature thw ′.

  After the control unit performs the second control, the determination unit further exceeds the second threshold value β ′, and the degree of deviation between the temperature thw and the estimated control temperature thw ′ is a predetermined level γ. If it exceeds, it is determined that the first thermostat 18 of the thermostats 18 and 19 has an open failure. Further, when the degree of deviation is less than the predetermined degree γ (specifically, when the degree is less than the predetermined degree γ here), it is determined that both the thermostats 18 and 19 are normal.

  The determination unit assumes that the degree of deviation exceeds a predetermined degree γ, specifically, the temperature thw is a third predetermined value whose temperature is lower than the estimated control temperature thw ′ by a predetermined degree γ. If it is below the threshold γ ′, the determination is made as described above. Therefore, the determination unit determines that the degree of deviation is lower than the predetermined degree γ, specifically, the case where the temperature thw is higher than the third threshold γ ′ (specifically, the third threshold here). If it is equal to or greater than γ ′, the determination is made as described above. The third threshold γ ′ can be calculated when the estimated control temperature thw ′ is calculated.

  The comparison between the temperature thw and the first threshold value α ′ may be performed, for example, by determining whether the temperature thw is equal to or lower than the first threshold value α ′ or exceeds the first threshold value α ′. This is the same when the comparison target of the temperature thw is, for example, the first target temperature α or the threshold values β ′, γ ′, and δ. Each of the predetermined degrees applied to the threshold values α ′ and β ′ and the predetermined degree γ may be different from each other. In the present embodiment, a fluid control system including thermostats 18 and 19, valve mechanisms V1 and V2, and an ECU 30 is realized.

  Next, the control operation of the fluid supply system of the present embodiment will be described using the flowchart shown in FIG. The ECU 30 determines whether or not the temperature thw is below the fourth threshold value δ and above the first threshold value α ′ (step S1). As shown in FIG. 7, the first threshold value α ′ is set to a temperature lower than the first target temperature α by a predetermined degree. The fourth threshold δ is set to a value lower than the first target temperature α and higher than the first threshold α ′. In this flowchart, it is confirmed at the same time that the low liquid temperature control is performed because the temperature thw is lower than the first target temperature α. The ECU 30 may separately determine whether or not the low liquid temperature control is performed based on, for example, the flow control state of the valve mechanisms V1 and V2 (phase of the rotary valve body 13). If a negative determination is made in step S1, this flowchart is temporarily terminated.

  If an affirmative determination is made in step S1, the ECU 30 determines whether or not to enter the failure diagnosis mode (step S2). In step S <b> 2, for example, based on the operating state of the engine 2, it can be determined whether or not there is an obstacle to entering the failure diagnosis mode. Then, when there is no trouble, it can be determined to enter the failure diagnosis mode. If a negative determination is made in step S2, this flowchart is temporarily terminated.

  If an affirmative determination is made in step S2, the ECU 30 controls the second valve mechanism V2 so as to limit the flow of the coolant (step S3). Thus, as a result of the first control being performed, the fluid flow control by the second thermostat 19 is switched from the valid state to the invalid state. Subsequently, the ECU 30 determines whether or not the temperature thw has increased (step S4). Whether or not the temperature thw has risen can be determined, for example, by whether or not the temperature thw has exceeded the fourth threshold value δ.

  If a negative determination is made in step S4, the ECU 30 determines that only the second thermostat 19 has an open failure (step S11). On the other hand, if an affirmative determination is made in step S4, the ECU 30 determines whether only the first thermostat 18 has an open failure, whether both the thermostats 18, 19 have an open failure, or both the thermostats 18, 19 are normal. Is determined (step S5).

  Subsequent to step S5, the ECU 30 controls the first valve mechanism V1 so as to restrict the flow of the coolant and also controls the second valve mechanism V2 so as to release the restriction on the flow of the coolant (step S6). ). Thus, as a result of the second control being performed, the flow of the coolant to the engine 2 is limited. Subsequently, the ECU 30 determines whether or not the temperature thw is lower than the second threshold value β ′ (step S7).

  If an affirmative determination is made in step S7, the ECU 30 determines that both the thermostats 18 and 19 have an open failure (step S12). On the other hand, if the determination is negative, the ECU 30 determines that only the first thermostat 18 has an open failure or that both the thermostats 18 and 19 are normal (step S8). Following step S8, the ECU 30 calculates the estimated control temperature thw ′ and the third threshold value γ ′ (step S9). Subsequently, the ECU 30 determines whether or not the temperature thw is lower than the third threshold γ ′ (step S10).

  If an affirmative determination is made in step S10, the ECU 30 determines that only the first thermostat 18 has an open failure (step S13). On the other hand, if the determination is negative, the ECU 30 determines that both the thermostats 18 and 19 are normal (step S14). After steps S11, 12, 13, and 14, this flowchart is terminated. When it is determined that a failure has occurred in steps S11, S12, and S13, the ECU 30 can perform operation control of the engine 2 in accordance with the failure mode. When it is determined in step S14 that the engine is normal, the ECU 30 can perform operation control of the engine 2 as usual.

  Next, the effect of the fluid control system of the present embodiment will be described. Here, when the temperature thw is lower than at least the first target temperature α in the state of performing the low liquid temperature control, control is performed so that the temperature thw increases as a result of the thermostats 18 and 19 being originally closed. This is equivalent to At the same time, this corresponds to the case where the temperature thw may be lowered as a result of at least one of the thermostats 18 and 19 having an open failure.

  On the other hand, in such a case, the fluid control system performs the first control for controlling the second valve mechanism V2 so as to restrict the flow of the coolant. In this regard, if the temperature thw rises after the first control is performed, it can be determined that the temperature thw has risen as a result of restricting the flow of the coolant through the second thermostat 19. . Therefore, in this case, the fluid control system can detect the open failure of the second thermostat 19 by determining that the second thermostat 19 has an open failure.

  In this regard, in the fluid control system, when the temperature thw is at least lower than the first target temperature α, the temperature thw is lower than the first target temperature α and exceeds the first threshold value α ′. By doing so, it can be detected that the second thermostat 19 among the thermostats 18 and 19 has an open failure.

  That is, for example, when both the thermostats 18 and 19 are in an open failure state, and the temperature thw is in a state of being lowered, the flow of the coolant through the first thermostat 18 after the first control is performed. As a result, only the temperature thw may increase. On the other hand, in the fluid control system, the case where the temperature thw is at least lower than the first target temperature α is the case described above, so that the thermostat 18 and 19 can be distinguished from the case where both the thermostats 18 and 19 are open. 18 and 19, it can be detected that the second thermostat 19 has an open failure. Therefore, specifically, the first threshold value α ′ can be set to a value that can distinguish these cases.

  In the fluid control system, when the temperature thw is at least lower than the first target temperature α, the temperature thw is further lower than the fourth threshold value δ and is higher than the first threshold value α ′. When the possibility of failure is high, the failure diagnosis mode can be entered. As a result, the failure can be detected suitably.

  When the temperature thw does not increase after the first control, the fluid control system controls the first valve mechanism V1 so as to further restrict the circulation of the cooling liquid and releases the restriction on the circulation of the cooling liquid. Thus, the second control for controlling the second valve mechanism V is performed. Then, after performing the second control, when the temperature thw is at least lower than the second target temperature β, a failure can be determined as follows.

  That is, when the second control is performed, the supply of the coolant to the engine 2 is restricted by the first valve mechanism V1. At this time, if both the thermostats 18 and 19 are normal, both the thermostats 18 and 19 are in the valve-closed state. Therefore, the first bypass valve 16 interlocked with the first thermostat 18 is in the valve open state. For this reason, in this case, the coolant is supplied to the engine 2 via the first bypass valve 16, and as a result, the engine 2 receives heat of the coolant. In this state, the temperature thw is controlled to be the second target temperature β.

  On the other hand, when the first thermostat 18 has an open failure, the flow of the coolant through the first bypass valve 16 is restricted, so that the coolant flow to the engine 2 is restricted. Therefore, as a result of limiting the heat receiving of the coolant from the engine 2, the temperature thw is at least lower than the second target temperature β.

  For this reason, the distribution control system determines that the first thermostat 18 has an open failure when the temperature thw is at least lower than the second target temperature β after performing the second control. An open failure of the first thermostat 18 can also be detected. In this regard, in the fluid control system, when the temperature thw is at least lower than the second target temperature β, the temperature thw is lower than the second threshold value β ′. It is possible to detect that both the thermostats 18 and 19 are open-failed while distinguishing from the case where one thermostat 18 is open-failed.

  This is because, when both the thermostats 18 and 19 have an open failure, the flow rate of the coolant flowing through the thermostats 18 and 19 increases more than when the first thermostat 18 has an open failure. This is because the temperature thw tends to decrease. Therefore, specifically, the second threshold value β ′ can be set within the range of the temperature thw that can distinguish these cases.

  After performing the second control, when the temperature thw is lower than the second threshold value β ′, and the degree of deviation between the temperature thw and the estimated control temperature thw ′ exceeds a predetermined degree γ Can be determined as follows. In other words, it can be determined that a deviation occurs between the temperature thw and the estimated control temperature thw ′ as a result of the open failure of the first thermostat 18 of the thermostats 18 and 19.

  For this reason, in this case, by determining that the first thermostat 18 of the thermostats 18 and 19 is open, the fluid control system further controls the thermostats 18 and 19. It can also be detected that the first thermostat 18 has an open failure. Therefore, the predetermined degree γ can be set to a value that can distinguish between the case where the first thermostat 18 of the thermostats 18 and 19 has an open failure and the case where both the thermostats 18 and 19 are normal.

  In addition, the fluid control system further allows the first thermostat 18 of the thermostats 18 and 19 to have an open failure, the second thermostat 19 to have an open failure, and both the thermostats 18 and 19 to have an open failure. Can be detected while distinguishing each other.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

  For example, the first and second valve mechanisms may be realized by a single valve (for example, a solenoid valve). In this respect, the first and second valve mechanisms can be driven by a single actuator by realizing the first and second valve mechanisms by the rotary valve bodies arranged in the first and second portions. it can. As a result, a cost-effective configuration can be obtained. Moreover, as a result, it becomes possible to configure a rotary valve that can be provided directly to the W / P, for example, so that simplification and compactness of the cooling circuit can be suitably achieved by integrating the circuit configuration. .

W / P 1
Engine 2
Radiator 6
Rotating valve body 13
First thermostat 18
Second thermostat 19
ECU 30
Fluid supply path PS
First branch path PB1
Second branch path PB2
First valve mechanism V1
Second valve mechanism V2

Claims (3)

Of the first and second branch paths that merge after branching, a first thermostat provided in the first branch path;
A second thermostat provided in the second branch path and having a valve opening temperature set lower than that of the first thermostat;
The fluid supply path that includes the first and second branch paths and supplies fluid to the supply target is provided in a first portion that is a part after the first and second branch paths merge. 1 valve mechanism;
A second valve mechanism provided in a second portion of the second branch path, which is a portion downstream of the second thermostat;
In a state where the first and second valve mechanisms have released the fluid flow restriction, the fluid control temperature is at least below a first target temperature that is a temperature to be controlled according to the state, And a first control that controls the second valve mechanism to restrict the flow of fluid when the temperature exceeds a first predetermined value that is lower by a predetermined degree than the first target temperature. A control unit to perform,
A determination unit configured to determine that the second thermostat remains open when the control temperature of the fluid rises after the control unit performs the first control; A fluid control system comprising: The fluid control system of claim 1,
A bypass path for bypassing the first valve mechanism in the first portion;
By operating in conjunction with the first thermostat, the bypass path communicates with the first thermostat closed, and the bypass path opens with the first thermostat opened. And a bypass valve for shutting off,
When the control temperature of the fluid does not rise after the controller performs the first control, the first valve mechanism is controlled to further restrict the fluid flow and the fluid flow restriction is released. To perform a second control to control the second valve mechanism,
After the control unit performs the second control, the control temperature of the fluid is such that the first valve mechanism restricts the fluid flow and the second valve mechanism releases the fluid flow restriction. When the temperature is below a second predetermined value that is lower than a second target temperature, which is a temperature to be controlled according to the state, by a predetermined degree, the first thermostat remains open. A fluid control system that determines that an open failure has occurred. The fluid control system according to claim 2,
An estimation unit for estimating a control temperature of the fluid when the first and second thermostats are normal;
After the control unit performs the second control, the control temperature of the fluid exceeds the second predetermined value, and between the control temperature of the fluid and the estimated control temperature that is the control temperature estimated by the estimation unit. When the degree of divergence of the first and second thermostats exceeds a predetermined level, the determination unit has an open failure that causes the first thermostat to remain open among the first and second thermostats. Fluid control system to judge

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