JP6881261B2 - Internal combustion engine cooling system - Google Patents

Description

The present invention relates to a cooling device for an internal combustion engine.

The cooling device for an internal combustion engine described in Patent Document 1 has one end connected to the engine body of the internal combustion engine and has a first cooling water flow path into which the cooling water discharged from the engine body flows. A radiator is arranged in the middle of the first cooling water flow path. The other end of the first cooling water flow path is connected to the engine body, and the cooling water discharged to the first cooling water flow path is returned to the engine body again via the radiator. The cooling device of the internal combustion engine has a second cooling water flow path that branches from a portion of the first cooling water flow path in front of the radiator to flow the cooling water to the EGR cooler. In the first cooling water flow path, a flow rate control valve is arranged at a branch portion to which the second cooling water flow path is connected.

The flow rate control valve has a tubular housing and a valve body arranged inside the housing. The valve body is rotatably provided with the axis of the housing as the center of rotation. A sector gear is connected to the valve body. A reduction gear that is rotationally driven by a control motor meshes with the sector gear. The flow control valve rotates the valve body with respect to the housing by rotating the sector gear via the reduction gear by the control motor. The flow rate of the cooling water supplied to the radiator through the first cooling water flow path and the flow rate of the cooling water flowing from the first cooling water flow path to the second cooling water flow path are adjusted according to the rotation phase of the valve body of the flow rate control valve. To. Further, by controlling the rotation phase of the valve body of the flow rate control valve to a predetermined phase, the flow of cooling water in the first cooling water flow path and the second cooling water flow path is stopped.

Japanese Unexamined Patent Publication No. 2016-8572

The valve body provided in the flow control valve is rotationally driven by a gear mechanism including a reduction gear and a sector gear. Stress is generated on the gear mechanism by the action of a force transmitted from the motor during driving. The driving stress accumulated by driving the gear mechanism causes the gear mechanism to fatigue, which contributes to a decrease in the durability of the flow rate control valve. When driving the flow rate control valve, it is desirable to control the output of the control motor in consideration of the influence of the drive stress accumulated in the flow rate control valve. This point is described in Patent Document 1. There is no disclosure in the cooling system of the internal combustion engine.

The cooling device for an internal combustion engine for solving the above problems is a water jacket formed in the engine body of the internal combustion engine and forming a cooling water passage for cooling the engine body, and cooling water is applied to the water jacket. It has a cooling water pump to be supplied, a hollow housing, a valve body arranged inside the housing, and a gear connected to the valve body to rotate the valve body relative to the housing. It is applied to an internal combustion engine provided with a control valve that adjusts the flow rate of cooling water discharged from the water jacket by rotating the gear with a motor, and estimates the stress generated in the control valve by the rotational drive of the valve body. The values are integrated to calculate the drive stress of the control valve, and when the drive stress is large, the output of the motor when driving the control valve is made smaller than when the drive stress is small.

In the above configuration, when the drive stress of the control valve is large, the drive output of the motor is made smaller than when the drive stress is small. Therefore, in a state where the driving stress of the control valve is large and its durability tends to decrease, it is possible to suppress the force acting on the component parts such as the gear of the control valve from the motor or the like. Therefore, the control valve can be driven appropriately.

The schematic diagram which shows the schematic structure of the cooling device of the internal combustion engine of one Embodiment. Perspective view of the control valve. An exploded perspective view of the control valve. A perspective view of the control valve housing as viewed from below. Perspective view of the rotor. A graph showing the relationship between the rotor phase and the aperture ratio of each port. Block diagram of temperature control. (A) to (c) are timing charts showing changes in each parameter in temperature control.

An embodiment of a cooling device for an internal combustion engine will be described with reference to FIGS. 1 to 8.
As shown in FIG. 1, the engine body 200 of an internal combustion engine includes a cylinder block 201 and a cylinder head 202 connected to the upper end of the cylinder block 201. The cooling water passage 10 for flowing the cooling water to the internal combustion engine has a water jacket 20 formed inside the engine main body 200. The water jacket 20 includes a block-side water jacket 20A formed on the cylinder block 201 and a head-side water jacket 20B formed on the cylinder head 202 and communicating with the block-side water jacket 20A.

The entrance of the water jacket 20 is open to the cylinder block 201. One end of the introduction pipe 21 is connected to this opening. The other end of the introduction pipe 21 is connected to the cooling water pump 22. The cooling water pump 22 is an engine-driven pump driven by a crankshaft of an internal combustion engine. By driving the cooling water pump 22 with the rotation of the crankshaft, the cooling water is supplied from the cooling water pump 22 to the water jacket 20 through the introduction pipe 21.

The outlet of the water jacket 20 is open to the cylinder head 202. One end of the lead-out pipe 23 is connected to this opening. The other end of the lead-out pipe 23 is connected to the control valve 30. The lead-out pipe 23 is provided with a water temperature sensor 24 that detects the temperature of the cooling water flowing through the lead-out pipe 23 (hereinafter referred to as “outlet water temperature Tout”).

The control valve 30 is provided with three outlets for cooling water. A first cooling water path 90 for flowing cooling water is connected to one of the three discharge ports via the radiator 92. The first cooling water path 90 connects the first radiator pipe 91, one end of which is connected to the discharge port, the radiator 92 connected to the other end of the first radiator pipe 91, the radiator 92, and the cooling water pump 22. It is composed of a second radiator pipe 93.

One of the three discharge ports of the control valve 30 is a second cooling water path for flowing cooling water via devices provided in various parts of the internal combustion engine such as the throttle body 102 and the EGR valve 103. 100 is connected. The second cooling water path 100 has a first device pipe 101 whose one end is connected to the discharge port. The downstream end of the first device pipe 101 is branched into three branches, and the branched ends are connected to the throttle body 102, the EGR valve 103, and the EGR cooler 104, respectively. The second cooling water path 100 has a second device pipe 105. The second device pipe 105 includes an upstream branch portion 105A, a merging portion 105B connected to the upstream branch portion 105A, and a downstream branch portion 105C connected to the merging portion 105B. The upstream branch 105A has a three-pronged end on the upstream side, and the branched end is connected to the throttle body 102, the EGR valve 103, and the EGR cooler 104. The confluence 105B constitutes one passage. The downstream branch portion 105C has a bifurcated end on the downstream side, and the branched end is connected to the oil cooler 106 and the ATF warmer 107.

The second cooling water path 100 has a third device pipe 108. The upstream end of the third device pipe 108 is bifurcated, and the branched end is connected to the oil cooler 106 and the ATF warmer 107. The downstream end of the third device pipe 108 is connected to the second radiator pipe 93. In the second cooling water path 100, the cooling water flowing from the control valve 30 to the first device pipe 101 branches into the throttle body 102, the EGR valve 103, and the EGR cooler 104 and flows. The cooling water that has passed through any of the throttle body 102, the EGR valve 103, and the EGR cooler 104 merges once in the second device pipe 105, and then branches and flows into the oil cooler 106 and the ATF warmer 107. The cooling water that has passed through either the oil cooler 106 or the ATF warmer 107 merges in the third device pipe 108 and flows to the cooling water pump 22 through the second radiator pipe 93.

A third cooling water path 110 for circulating cooling water is connected to one of the three discharge ports of the control valve 30 to the heater core 112 of the air conditioner provided in the vehicle. The third cooling water path 110 has one end connected to the first heater pipe 111 having one end connected to the discharge port, the heater core 112 connected to the other end of the first heater pipe 111, and the heater core 112. It is composed of a second heater pipe 113. The other end of the second heater pipe 113 is connected to the third device pipe 108. The cooling water flowing through the first heater pipe 111 passes through the heater core 112 and then flows to the third device pipe 108 through the second heater pipe 113. The cooling water flowing through the third device pipe 108 flows to the cooling water pump 22 through the second radiator pipe 93. In this way, the cooling water flowing from the control valve 30 to the cooling water paths 90, 100, 110 merges in front of the cooling water pump 22, and is supplied to the water jacket 20 again by the cooling water pump 22.

The control valve 30 is provided with a relief passage 115. The relief passage 115 communicates the inside of the control valve 30 with the first cooling water passage 90. A relief valve 116 is provided in the relief passage 115. The relief valve 116 opens when the pressure difference between the pressure on the control valve 30 side and the pressure on the first radiator pipe 91 side in the relief passage 115 becomes equal to or higher than a predetermined pressure, and the relief valve 116 opens from the control valve 30 to the first cooling water path. The cooling water is flowed to 90. That is, the relief valve 116 suppresses the pressure in the control valve 30 from becoming excessively high.

The structure of the control valve 30 will be described with reference to FIGS. 2 to 5.
As shown in FIG. 2, the control valve 30 has three ports that are outlets for cooling water. That is, the control valve 30 has a radiator port P1 to which the first cooling water path 90 is connected, a device port P2 to which the second cooling water path 100 is connected, and a heater port P3 to which the third cooling water path 110 is connected. And have. Each port P1, P2, P3 is open in a different direction. The inner diameter of the device port P2 and the inner diameter of the heater port P3 are the same. The inner diameter of the radiator port P1 is larger than the inner diameter of the device port P2 and the heater port P3.

As shown in FIG. 3, the control valve 30 includes a housing 40, a rotor 60 as a valve body, a rotation mechanism 70, and a cover 80 as its components. The housing 40 is formed in a hollow shape and constitutes the skeleton of the control valve 30. The housing 40 includes a main body 41, a first connector 51 attached to the main body 41, a second connector 52, and a third connector 53. The first connector portion 51 includes a first bulging portion 51A formed in a bottomed cylindrical shape, a plate-shaped first flange portion 51B connected to the opening peripheral edge of the first bulging portion 51A, and a first. It is composed of a cylindrical first port portion 51C connected to the bottom wall of the bulging portion 51A. The first connector portion 51 is a component of the radiator port P1. The second connector portion 52 includes a second port portion 52A formed in a cylindrical shape and a plate-shaped second flange portion 52B connected to an opening peripheral edge at one end of the second port portion 52A. The second connector portion 52 is a component of the device port P2. The third connector portion 53 includes a cylindrical third port portion 53A and a plate-shaped third flange portion 53B connected to the peripheral edge of the opening at one end of the third port portion 53A. The third connector portion 53 is a component of the heater port P3. The main body 41 is provided with a first mounting 42 to which the first connector 51 is mounted, a second mounting 43 to which the second connector 52 is mounted, and a third mounting 44 to which the third connector 53 is mounted. Has been done. The first connector portion 51 is attached to the first attachment portion 42 by bolts 56. Further, the second connector portion 52 is attached to the second attachment portion 43 by a bolt 56, and the third connector portion 53 is attached to the third attachment portion 44 by a bolt (not shown).

Two holes having different opening areas are formed in the first mounting portion 42. A relief valve 116 is assembled to the first hole 42A having a small opening area among these holes. The first connector portion 51 is attached to the first attachment portion 42 with the relief valve 116 assembled in the first hole 42A. As a result, the relief valve 116 is housed inside the housing 40. Of the two holes provided in the first mounting portion 42, the first hole 42A constitutes a part of the relief passage 115, and the second hole 42B having a larger opening area than the first hole 42A is the radiator port P1. It constitutes a part. The passage cross-sectional area of the radiator port P1 is larger than the passage cross-sectional areas of the heater port P3 and the device port P2. In the control valve 30, a sufficient relief amount is secured by providing the relief valve 116 in the radiator port P1.

As shown in FIG. 4, the main body 41 is provided with an opening 45 at the lower end, and a partition wall 46 for partitioning the main body 41 in the vertical direction is provided inside the opening 45. Inside the main body 41, the lower space partitioned by the partition wall 46 is referred to as an inflow space 47, and the upper space is referred to as an accommodation space 48. The radiator port P1, the device port P2, and the heater port P3 communicate with the inflow space 47. The partition wall 46 is formed with a support hole 49 that communicates the inflow space 47 and the accommodation space 48. At the opening edge of the support hole 49, a sliding contact portion 50 projecting in a cylindrical shape is erected on the inflow space 47 side. A stopper 55 projecting outward in the radial direction is connected to the outer surface of the sliding contact portion 50.

As shown in FIG. 3, a rotor 60 is assembled from the lower end portion and a rotation mechanism 70 is assembled from the upper end portion inside the main body 41.
As shown in FIG. 5, the rotor 60 has a valve body 61 and a rotor shaft 65 inserted through the valve body 61. The valve body 61 has a first valve portion 62 arranged on the upper side of FIG. 5 and a second valve portion 63 arranged on the lower side. The first valve portion 62 is formed in a tubular shape whose diameter is enlarged toward the central portion in the central axis direction (vertical direction in FIG. 5) of the rotor shaft 65. A first through hole 62A extending in the circumferential direction is formed on the side wall of the first valve portion 62. The inner region and the outer region of the first valve portion 62 are communicated with each other by the first through hole 62A. A protruding wall 62B extending radially inward is connected to the upper end of the first valve portion 62. A support wall 62C formed in an annular shape is connected to the tip of the protruding wall 62B. A locking hole 62D extending in an arc shape in the circumferential direction is formed at the upper end of the first valve portion 62.

The second valve portion 63 is formed in a tubular shape, and its inner region communicates with the inner region of the first valve portion 62. A second through hole 63A is formed on the side wall of the second valve portion 63. The second through hole 63A extends longer in the circumferential direction than the first through hole 62A.

The rotor shaft 65 is formed in the shape of a cylindrical rod, and is inserted and connected to the support wall 62C of the first valve portion 62. The rotor shaft 65 extends through the valve body 61 in the vertical direction. A bearing 66 is connected to the upper end of the rotor shaft 65. A seal 67 is connected to the rotor shaft 65 below the bearing 66 and above the support wall 62C. The seal 67 is formed in a disk shape. When the rotor shaft 65 rotates, the valve body 61 rotates around the rotor shaft 65 as the center of rotation. In the rotor 60, the upper end portion of the rotor shaft 65 in the state where the bearing 66 is not connected is inserted into the support hole 49 of the partition wall 46 of the housing 40 and protrudes toward the accommodation space 48, and the bearing is provided at the protruding upper end portion. By connecting 66, it is assembled to the housing 40. In this state, the valve body 61 and the seal 67 are arranged in the inflow space 47, and the bearing 66 is arranged in the accommodation space 48. The bearing 66 supports the rotor shaft 65 and the valve body 61 so as to be rotatable relative to the housing 40 by being connected to the upper surface of the partition wall 46. The seal 67 comes into contact with the lower surface of the sliding contact portion 50, and slides with the lower surface of the sliding contact portion 50 as the rotor shaft 65 rotates.

When the rotor 60 is housed in the housing 40, the stopper 55 is arranged in the locking hole 62D of the valve body 61. When the rotor 60 rotates relative to the housing 40, the stopper 55 moves relative to the locking hole 62D in the circumferential direction. When the stopper 55 comes into contact with the protruding wall 62B, the relative rotation of the rotor 60 with respect to the housing 40 is restricted. As described above, the valve body 61 of the rotor 60 can rotate relative to the housing 40 within a predetermined range until the stopper 55 abuts on the protruding wall 62B.

The rotor 60 communicates the first through hole 62A with the radiator port P1 when the relative rotation phase of the rotor 60 with respect to the housing 40 (hereinafter referred to as “rotor phase θ”) is within a certain range. That is, when the rotor phase θ is not in this range, the radiator port P1 is closed by the valve body 61. Further, the rotor 60 communicates the second through hole 63A with at least one of the device port P2 and the heater port P3 when the rotor phase θ is in another range.

In the control valve 30, the lead-out pipe 23 is connected to the lower end of the housing 40. As a result, the cooling water that has flowed through the water jacket 20 flows into the inflow space 47 through the outlet pipe 23. The cooling water supplied from the lead-out pipe 23 to the inflow space 47 flows into the inner region of the rotor 60, and when the first through hole 62A and the radiator port P1 are in communication with each other, the cooling water is cooled from the inflow space 47 to the radiator port P1. Flows. Further, when the second through hole 63A and the device port P2 are in communication with each other, cooling water flows from the inflow space 47 to the device port P2, and when the second through hole 63A and the heater port P3 are in communication with each other, the cooling water flows. Cooling water flows from the inflow space 47 to the heater port P3. The rotor 60 can also adjust the flow rate of the cooling water flowing through each port P1, P2, P3 by changing the flow path cross-sectional area of each port P1, P2, P3. The seal 67 is in sliding contact with the lower surface of the sliding contact portion 50 to suppress the flow of cooling water from the inflow space 47 to the accommodation space 48.

As shown in FIG. 3, the rotation mechanism 70 has a first gear 71 connected to the upper end of the rotor shaft 65 and a second gear 72 that meshes with the first gear 71. A motor 73 is connected to the second gear 72. When the motor 73 rotates the second gear 72, the rotor 60 is rotationally driven via the first gear 71. A detection sensor 74 for detecting the drive amount and drive speed of the motor 73, that is, the rotor phase θ and the rotor rotation speed V is attached to the motor 73. The detection sensor 74 includes a detection gear 75 that is rotationally driven by a motor 73, and a sensor unit 76 that detects the rotation phase and rotation speed of the detection gear 75. The sensor unit 76 is attached to the cover 80. The rotating mechanism 70 is arranged in the accommodation space 48 of the housing 40. The cover 80 is attached so as to close the upper end opening of the main body 41. As a result, the rotating mechanism 70 is housed inside the housing 40. The gears 71, 72, and 75 are made of resin.

Next, the relationship between the rotor phase θ of the control valve 30 and the aperture ratios of the ports P1, P2, and P3 will be described.
As shown in FIG. 6, in the control valve 30, the rotor phase θ when all the ports P1, P2, and P3 are closed is set to “0 °”. In this state, the valve body 61 of the rotor 60 can rotate in the clockwise direction (plus direction) and the counterclockwise direction (minus direction) in the axial direction viewed from the cover 80 side. Regarding the aperture ratio in each port P1, P2, P3, the opening area when fully opened is "100%" and the opening area when fully closed is "0%", and the opening ratio in each port P1, P2, P3 is It represents the ratio.

The aperture ratio of each port P1, P2, P3 changes depending on the rotor phase θ. That is, when the rotor 60 is rotated in the positive direction from the position where the rotor phase θ is “0 °”, the heater port P3 first starts to open. Then, the aperture ratio of the heater port P3 increases as the rotor phase θ increases in the positive direction. When the aperture ratio of the heater port P3 reaches "100%" and is fully opened, and then the rotor phase θ is further increased, the device port P2 starts to open next. Then, the aperture ratio of the device port P2 increases as the rotor phase θ increases in the positive direction. When the aperture ratio of the device port P2 reaches "100%" and is fully opened, and then the rotor phase θ is further increased, the radiator port P1 starts to open next. Then, the aperture ratio of the radiator port P1 increases as the rotor phase θ increases in the positive direction. Assuming that the rotor phase θ in which the protruding wall 62B and the stopper 55 abut is “β °”, the radiator port P1 is fully opened before the rotor phase θ reaches “β °”. From this state until the rotor phase θ reaches “β °”, the ports P1, P2, and P3 are fully open. As described above, in the control valve 30, the end of the movable range of the rotor 60 and the motor 73 in the positive direction is the position where the rotor phase θ is “β °”, and in this phase, the ports P1, P2, and P3 of each port P1, P2, and P3. Everything is fully open.

On the other hand, when the rotor 60 is rotated in the negative direction from the position where the rotor phase θ is “0 °”, the device port P2 first starts to open, and the aperture ratio of the device port P2 increases as the rotor phase θ increases in the negative direction. growing. After that, the radiator port P1 starts to open before the aperture ratio of the device port P2 reaches "100%", that is, a position slightly before the position where the device port P2 is fully opened. Then, as the rotor phase θ increases in the negative direction, the aperture ratio of the device port P2 increases and the device port P2 becomes fully open, and the aperture ratio of the radiator port P1 also increases. Assuming that the rotor phase θ in which the protruding wall 62B and the stopper 55 abut is “−α °”, the radiator port P1 is fully opened before the rotor phase θ reaches “−α °”. From this state until the rotor phase θ reaches “−α °”, the device port P2 and the radiator port P1 are fully open. As described above, in the control valve 30, the end of the movable range of the rotor 60 and the motor 73 in the minus direction is a position where the rotor phase θ is “−α °”, and in this phase, the radiator port P1 and the device port P2 are located. It is fully open. The heater port P3 is always fully closed in the range where the rotor phase θ is on the minus side of “0 °”.

As shown in FIG. 1, an output signal from the water temperature sensor 24 is input to the control device 130 of the internal combustion engine. Further, in the control device 130, in addition to the detection sensor 74 of the control valve 30, the outside temperature sensor 25 for detecting the outside temperature THA, the rotation speed sensor 26 for detecting the engine rotation speed NE of the internal combustion engine, and the operating amount of the accelerator pedal. An output signal from the accelerator sensor 27 or the like that detects the above is also input. The control device 130 adjusts the flow rate of the cooling water discharged from the water jacket 20 by driving the control valve 30 based on the output signals from the sensors 24, 25, 26, 27, 74 and the like. Further, the control device 130 executes temperature control control for controlling the outlet water temperature Tout of the cooling water by driving the control valve 30 based on the output signals from the sensors 24, 25, 26, 27, 74 and the like. ..

As shown in FIG. 7, the control device 130 has a target rotor phase calculation unit 131, a feedback term calculation unit 132, a feedback processing unit 133, a stress estimation value calculation unit 134, and a drive stress as functional units for controlling the control valve 30. It has a calculation unit 135, a stress storage unit 136, a limit value setting unit 137, and an output calculation unit 138. The control device 130 executes the driving amount of the control valve 30 in the temperature control as follows. This control is repeatedly executed at a predetermined control cycle during the operation of the internal combustion engine.

When the control device 130 starts this process, the target rotor phase calculation unit 131 first calculates the target rotor phase θt, which is the target value of the rotor phase θ of the control valve 30. The target rotor phase θt is set in different modes before and after the completion of warming up of the internal combustion engine. In the present embodiment, it is determined that the warm-up of the internal combustion engine is completed when the outlet water temperature Tout rises to the warm-up completion temperature T2 after the start of the internal combustion engine.

The target rotor phase θt before the completion of warming up of the internal combustion engine is set based on the outlet water temperature Tout. That is, when the outlet water temperature Tout is lower than the water stop completion temperature T1 (<warm-up completion temperature T2), the aperture ratios of the three ports of the radiator port P1, the device port P2, and the heater port P3 are all set to "0%". The position of the rotor phase θ (= 0 °) is set as the target rotor phase θt. As a result, the discharge of the cooling water from the water jacket 20 of the internal combustion engine is stopped, and the temperature rise of the engine body 200 is promoted. When the outlet water temperature Tout becomes the water stop completion temperature T1 or higher, the target rotor phase θt is increased to the plus side or the minus side according to the increase in the outlet water temperature Tout. In this case, if the outside air temperature THA is below the reference temperature and there is a high possibility that the heating of the vehicle will be used, the target rotor phase θt is increased to the plus side, and the outside air temperature THA exceeds the reference temperature and the heating is used. When it is unlikely that the target rotor phase θt will be increased to the negative side.

After the warm-up of the internal combustion engine is completed, the outlet water temperature Tout is feedback-controlled so as to reach the target water temperature set according to the operating condition of the internal combustion engine. The target water temperature is set to a low temperature in order to suppress the occurrence of knocking when the internal combustion engine is operated under the condition that knocking is likely to occur. Further, the target water temperature is set to a high temperature in order to reduce the viscosity of the lubricating oil and improve the fuel efficiency when the internal combustion engine is operated under the condition that knocking is unlikely to occur.

The target rotor phase calculation unit 131 calculates the target water temperature based on the engine rotation speed NE and the load KL of the internal combustion engine, and then calculates the target rotor phase θt according to the deviation of the outlet water temperature Tout with respect to the target water temperature. The load KL of the internal combustion engine can be calculated based on the engine rotation speed NE and the accelerator operation amount. The target rotor phase θt is calculated so that the opening ratio of the radiator port P1 is large when the outlet water temperature Tout is higher than the target water temperature, and the opening ratio of the radiator port P1 is small when the outlet water temperature Tout is lower than the target water temperature. Is calculated in.

When the target rotor phase θt is calculated in this way, the feedback processing unit 133 determines the required drive duty DUTYd of the motor 73 of the control valve 30 based on the deviation Δθ (= θt−θ) of the current rotor phase θ with respect to the target rotor phase θt. Feedback control. In the present embodiment, the feedback control of the required drive duty DUTYd is performed by PID control. The feedback term FAF used for feedback control is calculated by the feedback term calculation unit 132. The feedback term calculation unit 132 calculates the sum of the output values of the proportional element, the integrating element, and the differential element that input the deviation Δθ as the feedback term FAF.

Further, the control device 130 sets an upper limit and a lower limit of the drive duty DUTY, which is a duty ratio of the voltage applied to the motor 73 when executing the temperature control control.
That is, the stress estimation value calculation unit 134 calculates the stress estimation value ST, which is an estimation value of the stress generated in the control valve 30 by the rotational drive of the rotor 60. The stress estimated value calculation unit 134 calculates the stress estimated value ST every time the rotor 60 of the control valve 30 is rotationally driven. The stress estimate ST is calculated based on the rotor rotation speed V. When the rotor rotation speed V is high, the force acting on the gears 71, 72, 75 from the motor 73 when the rotor 60 is rotationally driven tends to be larger than when the rotor rotation speed V is low. Therefore, the stress estimation value calculation unit 134 calculates the stress estimation value ST so that the higher the rotor rotation speed V, the larger the stress estimation value ST. The relationship between the rotor rotation speed V and the stress estimated value ST is obtained in advance by simulation or the like and stored in the stress estimated value calculation unit 134.

When the stress estimate calculation unit 134 calculates the stress estimate ST _(n) this time, the drive stress calculation unit 135 calculates the stress estimate ST _{( n-1) to the integrated value ΣST (n-1) of the stress estimates up to the previous time. n)} is integrated to calculate the drive stress ΣST _(n) of the control valve 30. That is, the drive stress ΣST _(n) is an integrated value of the stress estimated value ST generated in the control valve 30. The drive stress ΣST _(n) calculated in this way is stored in the stress storage unit 136 as an integrated value ΣST _{(n-1) of the stress estimated values. The integrated value ΣST (n-1)} stored in the stress storage unit 136 is used when calculating the next drive stress ΣST _(n).

The limit value setting unit 137 calculates the limit of the drive duty DUTY based on _{the drive stress ΣST (n)} calculated by the drive stress calculation unit 135. As shown in FIG. 7, this limit is set stepwise according to the _{driving stress ΣST (n).} For example, when the drive stress ΣST _(n) is a value within the smallest 0th range, the limit is set to “0%”. In this case, in the drive duty DUTY, "+ 100%" is set as the upper limit value when driving the rotor 60 in the positive direction, and "-100%" is set as the lower limit value when driving the rotor 60 in the negative direction. Duty. That is, when the drive stress ΣST _(n) is a value within the 0th range, the drive duty DUTY can take a value from “+ 100%” to “-100%”. When the drive duty DUTY is "+ 100%" and "-100%", the output of the motor 73 becomes maximum, and the closer the value of the drive duty DUTY approaches 0, the smaller the output of the motor 73.

Further, when the drive stress ΣST _(n) is a value in the first range larger than the 0th range, the limit is set to a value α (> 0) larger than the value in the 0th range. In this case, in the drive duty DUTY, "+ (100-α)%" is set as the upper limit value when driving the rotor 60 in the positive direction, and "-("-( "100-α)%" is set. That is, when the drive stress ΣST _(n) is a value within the first range, the drive duty DUTY can take a value from "+ (100-α)%" to "-(100-α)%". Therefore, when the drive stress ΣST _(n) is a value within the first range, the range of values that the drive duty DUTY can take is _{larger than when the drive stress ΣST (n) is a value within the 0th range.} It gets narrower.

Further, when the driving stress ΣST _(n) is a value in the second range larger than the first range, the limit is set to a value β (> α) larger than the value α in the first range. In this case, in the drive duty DUTY, "+ (100-β)%" is set as the upper limit value when the rotor 60 is driven in the positive direction, and "-(" is the lower limit value when the rotor 60 is driven in the negative direction. "100-β)%" is set. That is, when the drive stress ΣST _(n) is a value within the second range, the drive duty DUTY can take a value from “+ (100-β)%” to “− (100-β)%”. Therefore, when the drive stress ΣST _(n) is a value within the second range, the range of values that the drive duty DUTY can take is _{larger than when the drive stress ΣST (n) is a value within the first range.} It gets narrower.

Further, when the driving stress ΣST _(n) is a value in the third range larger than the second range, the limit is set to a value γ (> β) larger than the value β in the second range. In this case, in the drive duty DUTY, "+ (100-γ)%" is set as the upper limit value when driving the rotor 60 in the positive direction, and "-("-( "100-γ)%" is set. That is, when the drive stress ΣST _(n) is a value within the third range, the drive duty DUTY can take a value from "+ (100-γ)%" to "-(100-γ)%". Therefore, when the drive stress ΣST _(n) is a value within the third range, the range of values that the drive duty DUTY can take is _{larger than when the drive stress ΣST (n) is a value within the second range.} It gets narrower.

Further, when the drive stress ΣST _(n) is a value in the fourth range larger than the third range, the limit is set to a value δ (> γ) larger than the value γ in the third range. In this case, in the drive duty DUTY, "+ (100-δ)%" is set as the upper limit value when driving the rotor 60 in the positive direction, and "-("-( "100-δ)%" is set. That is, when the drive stress ΣST _(n) is a value within the fourth range, the drive duty DUTY can take a value from "+ (100-δ)%" to "-(100-δ)%". Therefore, when the drive stress ΣST _(n) is a value within the fourth range, the range of values that the drive duty DUTY can take is _{larger than when the drive stress ΣST (n) is a value within the third range.} It gets narrower.

Further, when the drive stress ΣST _(n) is a value in the fifth range larger than the fourth range, the limit is set to a value ε (> δ) larger than the value δ in the fourth range. In this case, in the drive duty DUTY, "+ (100-ε)%" is set as the upper limit value when the rotor 60 is driven in the positive direction, and "-(" is the lower limit value when the rotor 60 is driven in the negative direction. "100-ε)%" is set. That is, when the drive stress ΣST _(n) is a value within the fifth range, the drive duty DUTY can take a value from "+ (100-ε)%" to "-(100-ε)%". Therefore, when the drive stress ΣST _(n) is a value within the fifth range, the range of values that the drive duty DUTY can take is _{larger than when the drive stress ΣST (n) is a value within the fourth range.} It gets narrower. As described above, when the drive stress ΣST _(n) is large, the value that the drive duty DUTY can take becomes narrower than when the drive stress ΣST _{(n) is small.}

When the upper limit value and the lower limit value of the drive duty DUTY are set in this way, the output calculation unit 138 calculates the drive duty DUTY of the motor 73 when executing the temperature control control. When the required drive duty DUTYd calculated by the feedback processing unit 133 is within the range from the upper limit value to the lower limit value set by the limit value setting unit 137, the output calculation unit 138 sets a value equal to the required drive duty DUTYd. Calculated as drive duty DUTY. Further, when the required drive duty DUTYd calculated by the feedback processing unit 133 exceeds the upper limit value set by the limit value setting unit 137, the output calculation unit 138 sets a value equal to the upper limit value as the drive duty DUTY. Calculate as. Further, when the required drive duty DUTYd calculated by the feedback processing unit 133 is lower than the lower limit value set by the limit value setting unit 137, the output calculation unit 138 sets the drive duty DUTY to a value equal to the lower limit value. Calculate as. When the absolute value of the drive duty DUTY is large, the operating speed of the control valve 30 becomes high, and the response speed of the rotor phase θ with respect to the target rotor phase θt becomes fast. As described above, when the operating speed of the control valve 30 is high, the rotor rotation speed V becomes high, and the stress estimated value ST generated in the control valve 30 becomes large. In the control device 130, the _{larger the drive stress ΣST (n)} , the lower the upper limit value of the drive duty DUTY and the higher the lower limit value of the drive duty DUTY. Therefore, when the drive stress ΣST _{(n) of} the control valve 30 is large, the absolute value of the drive duty DUTY is likely to be set to a small value. As a result, the output of the motor 73 can be reduced as compared with the case where the limit is not set, and the stress generated in the control valve 30 is reduced by slowing down the operating speed of the control valve 30.

Next, the operation and effect of the present embodiment will be described with reference to FIG.
As shown by the alternate long and short dash line in FIG. 8A, when the target rotor phase θt is changed to the positive side at the timing t1, the feedback processing unit 133 calculates the required drive duty DUTYd. In this example, the required drive duty DUTYd is calculated as "+ 80%". As shown in FIG. 8C, at the timing t1, the drive stress ΣST _(n) calculated by the drive stress calculation unit 135 is a value within the 0th range, and therefore is an upper limit value of the drive duty DUTY. Is set to "+ 100%" and the lower limit is set to "-100%". At the timing t1, the value of the required drive duty DUTYd is a value between the upper limit value shown by the alternate long and short dash line in FIG. 8 (b) and the lower limit value indicated by the alternate long and short dash line in FIG. 8 (b). Therefore, as shown by the solid line in FIG. 8B, a value equal to the required drive duty DUTYd is calculated as the drive duty DUTY of the motor 73.

After that, the output of the motor 73 is controlled by the calculated drive duty DUTY, so that the rotor phase θ is increased to the target rotor phase θt as shown by the solid line in FIG. 8A.

The required drive duty DUTYd is calculated as a gradually smaller value after the timing t2 in which the deviation Δθ between the rotor phase θ and the target rotor phase θt is correspondingly reduced. As a result, as shown by the solid line in FIG. 8B, the drive duty DUTY gradually becomes a small value. Then, at the timing t3 slightly before the timing t4 at which the rotor phase θ becomes the same as the target rotor phase θt, the drive duty DUTY becomes “0%”. The movement of the rotor 60 of the control valve 30 is delayed with respect to the change in the drive duty DUTY. Therefore, in the control of the rotor phase θ, the rotor phase θ increases even after the timing t3 when the drive duty DUTY becomes “0%”, and the rotor phase θ and the target rotor phase θt once match at the timing t4, but thereafter. , The rotor phase θ overshoots beyond the target rotor phase θt. The drive duty DUTY is calculated following such a change in the rotor phase θ, and is set to positive and negative values after the timing t4. Then, after the timing t5 when the rotor phase θ converges to the target rotor phase θt, the drive duty DUTY is maintained at “0%”. As a result, the flow rate of the cooling water flowing through the radiator port P1, the device port P2, and the heater port P3 of the control valve 30 is adjusted, and the outlet water temperature Tout of the cooling water is controlled to the target water temperature.

After that, a case where the drive stress ΣST accumulated in the control valve 30 increases with the use of the control valve 30 will be described.
As shown by the alternate long and short dash line in FIG. 8A, when the target rotor phase θt is changed to the positive side at the timing t6, the feedback processing unit 133 calculates the required drive duty DUTYd. In this example, the required drive duty DUTYd is calculated as "+ 80%". As shown in FIG. 8C, at the timing t6, the drive stress ΣST _(n) calculated by the drive stress calculation unit 135 is a value within the fifth range, and therefore is an upper limit value of the drive duty DUTY. Is set to "+ (100-ε)%" and the lower limit is set to "-(100-ε)%". At the timing t6, the value of the required drive duty DUTYd shown by the alternate long and short dash line in FIG. 8 (b) exceeds the upper limit value shown by the alternate long and short dash line in FIG. 8 (b). Therefore, as shown by the solid line in FIG. 8B, the drive duty DUTY is calculated as a value equal to the upper limit value, not as the required drive duty DUTYd. As a result, the drive duty DUTY becomes a value smaller than the required drive duty DUTYd.

After that, the output of the motor 73 is controlled by the calculated drive duty DUTY, so that the rotor phase θ is increased to the target rotor phase θt as shown by the solid line in FIG. 8A.

After the timing t7 when the deviation Δθ between the rotor phase θ and the target rotor phase θt is correspondingly reduced, the required drive duty DUTYd is calculated as a gradually smaller value. After that, after the timing t8 when the required drive duty DUTYd becomes equal to or less than the upper limit value, the drive duty DUTY is gradually reduced to a smaller value as shown by the solid line in FIG. 8B. Then, at the timing t9 slightly before the timing t10 when the rotor phase θ becomes the same as the target rotor phase θt, the drive duty DUTY becomes “0%”. The movement of the rotor 60 of the control valve 30 is delayed with respect to the change in the drive duty DUTY. Therefore, in the control of the rotor phase θ, the rotor phase θ increases even after the timing t9 when the drive duty DUTY becomes “0%”, and the rotor phase θ and the target rotor phase θt once match at the timing t10, but thereafter. , The rotor phase θ overshoots beyond the target rotor phase θt. The drive duty DUTY is calculated following such a change in the rotor phase θ, and is set to positive and negative values after the timing t10. Then, after the timing t11 when the rotor phase θ converges to the target rotor phase θt, the drive duty DUTY is maintained at “0%”. As a result, the flow rate of the cooling water flowing through the radiator port P1, the device port P2, and the heater port P3 of the control valve 30 is adjusted, and the outlet water temperature Tout of the cooling water is controlled to the target water temperature.

In the present embodiment, when the drive stress ΣST of the control valve 30 is large, the drive output of the motor 73 is reduced by reducing the drive duty DUTY as compared with the case where the drive stress ΣST is small. In the example shown in FIG. 8, the value of the required drive duty DUTYd at the timing t1 is equal to the value of the required drive duty DUTYd at the timing t6, but at the timing t6, the drive stress ΣST is large, so that the drive duty DUTY is required. It is limited to a value smaller than the drive duty DUTYd. In this case, as shown by the solid line in FIG. 8A, the rate of change (slope) of the rotor phase θ during the period from timing t6 to timing t10 is the rate of change (slope) of the rotor phase θ during the period from timing t1 to timing t4. ) Is smaller than. That is, when the drive stress ΣST is large, the operating speed of the control valve 30 can be lowered to lower the rotor rotation speed V. Therefore, in a state where the drive stress ΣST of the control valve 30 is large and its durability tends to decrease, the force acting from the motor 73 on the components such as the gears 71, 72, 75 of the control valve 30 can be suppressed. The control valve 30 can be driven appropriately.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
Although the configuration in which the motor 73 is provided as the rotation mechanism 70 of the control valve 30 has been described as an example, the arrangement of the motor 73 can be changed as appropriate. For example, the motor 73 may be provided as a configuration different from that of the control valve 30.

-The stress estimated value calculation unit 134 calculates the stress estimated value ST based on the rotor rotation speed V, but the calculation mode of the stress estimated value ST is not limited to this. For example, the stress estimated value ST may be calculated based on the rotor rotation speed V and the drive duty DUTY. That is, when the absolute value of the drive duty DUTY is large, the force acting on the gears 71, 72, 75 from the motor 73 when the rotor 60 is rotationally driven is compared with the case where the absolute value of the drive duty DUTY is small. Tends to be large. Therefore, when this configuration is adopted, the stress estimated value ST is calculated so as to be larger when the absolute value of the drive duty DUTY is large than when the absolute value of the drive duty DUTY is small. Further, the stress estimation value calculation unit 134 may calculate the stress estimation value ST based only on the drive duty DUTY without considering the rotor rotation speed V. Further, the stress estimation value calculation unit 134 calculates the stress estimation value ST based on the parameters different from the rotor rotation speed V and the drive duty DUTY and correlating with the stress generated in the control valve 30. Is also possible. For example, when the rotor 60 is rotationally driven to the limit of the movable range, the stopper 55 abuts on the protruding wall 62B to regulate the relative rotation of the rotor 60 with respect to the housing 40. In such a case, a force acts on the gears 71, 72, and 75 due to the collision between the stopper 55 and the protruding wall 62B. Therefore, it is also possible to calculate the stress estimated value ST based on the number of times the target rotor phase θt of the rotor 60 is set to the above-mentioned “α °” and “β °” which is the limit of the movable range. In this configuration, the higher the rotor rotation speed V, the greater the force acting on the gears 71, 72, and 75 due to the collision between the stopper 55 and the protruding wall 62B. Therefore, stress is estimated in consideration of these points. It is desirable to calculate the value ST.

As a mode for calculating the drive stress ΣST, the stress storage unit 136 stores the drive stress ΣST calculated by the drive stress calculation unit 135, and the stored drive stress ΣST stores the stress newly calculated by the stress estimation value calculation unit 134. A method of integrating the estimated value ST has been illustrated. The mode for calculating the driving stress ΣST is not limited to this. For example, all of the stress estimation value ST calculated by the stress estimation value calculation unit 134 is stored in the stress storage unit 136, and in the driving stress calculation unit 135, all of the stress estimation value ST is stored in the stress storage unit 136, or within a predetermined period. The driving stress ΣST may be calculated by integrating the stress estimated value ST.

-In the limit value setting unit 137, the limit is set stepwise according to the drive stress ΣST, but it is also possible to set the limit so that the larger the drive stress ΣST is, the larger the limit is. For example, the limit may be set in a proportional relationship so that the drive stress ΣST increases as the drive stress ΣST increases.

-The limit value setting unit 137 applies the set limit to both the upper limit value and the lower limit value of the drive duty DUTY, but it may be applied to only one of them. Further, the limit value setting unit 137 may set the upper limit value and the lower limit value separately.

In the above embodiment, when the drive stress ΣST is large, the upper limit value of the drive duty DUTY is made smaller and the lower limit value is made larger than when the drive stress ΣST is small so that the output of the motor 73 is reduced. I made it. The method of reducing the output of the motor 73 is not limited to this. In short, when the drive stress ΣST is large, the output of the motor 73 may be reduced by reducing the power supplied to the motor 73 as compared with the case when the drive stress ΣST is small.

10 ... Cooling water passage, 20 ... Water jacket, 20A ... Block side water jacket, 20B ... Head side water jacket, 21 ... Introduction piping, 22 ... Cooling water pump, 23 ... Derivation piping, 24 ... Water temperature sensor, 25 ... Outside temperature Sensor, 26 ... Rotation speed sensor, 27 ... Accelerator sensor, 30 ... Control valve, 40 ... Housing, 41 ... Main body, 42 ... 1st mounting part, 42A ... 1st hole, 42B ... 2nd hole, 43 ... 2nd Mounting part, 44 ... 3rd mounting part, 45 ... opening, 46 ... partition wall, 47 ... inflow space, 48 ... accommodation space, 49 ... support hole, 50 ... sliding contact part, 51 ... first connector part, 51A ... 1 bulging part, 51B ... 1st flange part, 51C ... 1st port part, 52 ... 2nd connector part, 52A ... 2nd port part, 52B ... 2nd flange part, 53 ... 3rd connector part, 53A ... 3 port part, 53B ... 3rd flange part, 55 ... stopper, 56 ... bolt, 60 ... rotor, 61 ... valve body, 62 ... 1st valve part, 62A ... 1st through hole, 62B ... protruding wall, 62C ... support Wall, 62D ... Locking hole, 63 ... 2nd valve, 63A ... 2nd through hole, 65 ... Rotor shaft, 66 ... Bearing, 67 ... Seal, 70 ... Rotating mechanism, 71 ... 1st gear, 72 ... 2 gears, 73 ... motor, 74 ... detection sensor, 75 ... detection gear, 76 ... sensor unit, 80 ... cover, 90 ... first cooling water path, 91 ... first radiator piping, 92 ... radiator, 93 ... second radiator Piping, 100 ... 2nd cooling water path, 101 ... 1st device piping, 102 ... Throttle body, 103 ... EGR valve, 104 ... EGR cooler, 105 ... 2nd device piping, 105A ... Upstream branch, 105B ... Confluence, 105C ... downstream branch, 106 ... oil cooler, 107 ... ATF warmer, 108 ... third device piping, 110 ... third cooling water path, 111 ... first heater piping, 112 ... heater core, 113 ... second heater piping, 115 ... Relief passage, 116 ... Relief valve, 130 ... Control device, 131 ... Target rotor phase calculation unit, 132 ... Feedback term calculation unit, 133 ... Feedback processing unit, 134 ... Stress estimation value calculation unit, 135 ... Drive stress calculation unit, 136 ... Stress storage unit, 137 ... Limit value setting unit, 138 ... Output calculation unit, 200 ... Engine body, 201 ... Cylinder block, 202 ... Cylinder head.

Claims (1)

A water jacket that is formed on the engine body of an internal combustion engine and constitutes a passage for cooling water that cools the engine body.
A cooling water pump that supplies cooling water to the water jacket,
It has a hollow housing, a valve body arranged inside the housing, and a gear connected to the valve body for rotating the valve body relative to the housing, and the gear is rotated by a motor. This applies to internal combustion engines equipped with a control valve that regulates the flow rate of cooling water discharged from the water jacket.
The estimated value of the stress generated in the control valve due to the rotational drive of the valve body is integrated to calculate the drive stress of the control valve. When the drive stress is large, the drive stress is smaller than when the drive stress is small. A cooling device for an internal combustion engine that reduces the output of the motor when driving a control valve.

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