JP2004108343A - Cooling device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve warmup performance by minimizing a time required for an initialization specifying the full open position of a valve disk in a cooling device of an internal combustion engine having a flow control valve controlling the flow rate of engine cooling water passing a radiator and performing the initialization when the engine is started. <P>SOLUTION: This cooling device of the internal combustion engine 1 comprises the flow control valve 14 controlling the flow rate of the engine cooling water passing the radiator 12. An electronic control device 40 drivingly opens the flow control valve 14 based on specified drive instruction values until the displacement of the valve element of the flow control valve 14 is restricted by a stopper, and performs the initialization specifying the full open position thereof when the engine is started. In addition, the electronic control device 40 performs the initialization when the engine is stopped and, after the initialization, holds the valve element at the full open position. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cooling device for an internal combustion engine in which the temperature of an engine cooling water passing through a radiator is controlled by controlling the opening degree of a flow control valve to control the temperature according to the engine operating state.
[0002]
[Prior art]
As such a cooling device for an internal combustion engine, for example, one described in Patent Document 1 can be mentioned. In this device, when the engine cooling water temperature at the time of engine stop is equal to or higher than a predetermined temperature, for example, when the engine is stopped immediately after high-load operation, the flow control valve is forcibly opened to stop the engine during stop. An excessive rise in the temperature of the engine cooling water which occurs in the engine is suppressed.
[0003]
Further, as described in Patent Document 2, for example, an apparatus employing a stepping motor as a drive source for driving the valve element of such a flow control valve has been proposed. In this device, since the positioning control of the valve element can be performed relatively accurately through the open loop control, a position sensor for detecting the opening degree of the flow control valve, that is, the position of the valve element, becomes unnecessary, and The configuration and control structure can be simplified.
[0004]
By the way, in a device not provided with such a position sensor, it is necessary to execute a process for specifying the current position of the valve body of the flow control valve (initialization process) at least once after the engine operation is started. There is. For example, in the case of Patent Document 2, the initialization process is performed at the time of starting the engine.
[0005]
In such initialization processing, for example, when the engine is started, the flow control valve is driven to open and the valve body is brought into contact with a stopper to mechanically stop the valve body at its fully open position. As a result, the current position of the valve element can be specified as the fully open position, and thereafter, a drive command value for relatively displacing the valve element from this fully open position to an arbitrary position is calculated, and the drive command value is calculated. Based on this, it becomes possible to execute position control of the valve element, that is, control of the opening degree of the flow control valve.
[0006]
Further, in the example of the initialization processing, a configuration is adopted in which a reference position for specifying the position of the valve element is set to the fully open position, and a stopper is provided for holding the position of the valve element at the full open position. For this reason, especially when the valve body is controlled to the fully open position, the positioning accuracy can be improved. As a result, if the cooling water temperature rises excessively during operation of the engine, the flow control valve can be reliably shifted to the fully open state, and the flow rate of the engine cooling water passing through the radiator is maximized to increase the overheating. Generation can be suppressed appropriately.
[0007]
[Patent Document 1]
JP-A-9-195768
[Patent Document 2]
JP 2002-21563 A
[0008]
[Problems to be solved by the invention]
However, when the above-described initialization processing is performed at the time of starting the engine, the following inconveniences cannot be ignored.
[0009]
In other words, in the initialization process, it is premised that the valve body is brought into contact with the stopper through the valve opening drive of the flow control valve so that the displacement is reliably regulated. Therefore, for example, even when the valve element is in the fully closed position, which is the most distant from the fully open position, the drive amount for opening the flow control valve to a size that can be reliably displaced to the fully open position is set in advance. Have been.
[0010]
However, when the drive amount of the flow control valve is set in this manner, the valve body can be reliably brought into contact with the stopper, but when the valve body is located at a position other than the fully closed position, especially when the valve body is in the vicinity of the fully open position. In this case, the valve opening drive of the flow control valve is performed for an unnecessarily long time. Therefore, in such a case, the time required for the initialization processing must be long.
[0011]
Also, at the time of cold start, after the initialization process is completed, the flow control valve is quickly shifted from the fully opened state to the fully closed state, and the introduction of cooling water to the radiator is stopped to warm up the internal combustion engine. Need to be promoted. However, as described above, if the initialization process is prolonged, the timing of shifting the flow control valve from the fully open state to the fully closed state after the engine is started is delayed, resulting in a decrease in warm-up properties.
[0012]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional circumstances, and has as its object to provide an initialization which includes a flow control valve for controlling the flow rate of engine cooling water passing through a radiator, and specifies a fully open position of the valve body. An object of the present invention is to improve the warm-up property by minimizing the time required for the initialization process in a cooling device for an internal combustion engine that performs the process when the engine is started.
[0013]
[Means for Solving the Problems]
The configuration for achieving the above object and the operation and effect thereof will be described below.
According to the first aspect of the present invention, there is provided a flow rate control valve for controlling the flow rate of the engine cooling water passing through the radiator of the internal combustion engine, and the flow rate control valve is set to a predetermined value until the displacement of the valve body is regulated by the stopper. In a cooling device for an internal combustion engine, which executes an initialization process for specifying the fully open position of the valve body by opening the valve based on the drive command value at the time of starting the engine, the initialization process is executed when the engine is stopped, and And a stop-time control means for driving and controlling the flow rate control valve so that the valve body is held at a predetermined position after the completion of the conversion process.
[0014]
According to this configuration, when the engine is stopped, the flow control valve is driven and controlled, so that the valve body of the flow control valve is held at a predetermined position. Therefore, in the above-mentioned initialization processing accompanying the engine start, under the situation where the current position of the valve body is grasped, the valve opening drive of the flow control valve is performed until the displacement of the valve body is regulated by the stopper. It will be good. Further, since the initialization process is performed before the valve body is held at the predetermined position when the engine is stopped, the positioning accuracy when the valve body is held at the predetermined position can be improved. Become like
[0015]
For example, in a configuration example in which a stepping motor is adopted as a drive source of the flow control valve, a step-out occurs due to vibration or the like, and the position of the valve body corresponding to the drive command value (step command value) and the actual position are determined. May occur. Therefore, when the initialization process is not performed, even if the valve body of the flow control valve is held at a predetermined position when the engine is stopped, the positioning accuracy is naturally compared with the case where the initialization process is performed. It has to be low. Therefore, in order to ensure that the valve body abuts against the stopper when the engine is started, the drive amount of the flow control valve is set to a large value in advance so that even if such a positional deviation due to step-out or the like has occurred, it can be absorbed. There is a need to.
[0016]
In this regard, according to the above-described configuration, even in the case where the position of the valve element is displaced during the operation of the engine, such as the position error due to the step-out of the stepping motor, the valve element is corrected with high accuracy after correcting this. Since the flow control valve can be held at the predetermined position, when the flow control valve is driven to open, the drive amount can be set to an appropriate size corresponding to the predetermined position. Therefore, it is possible to prevent the drive operation of the flow rate control valve from being performed more than necessary during the initialization process at the time of starting the engine, and it is possible to improve the warm-up property.
[0017]
According to a second aspect of the present invention, in the cooling device for an internal combustion engine according to the first aspect, the stop control means controls the stop so that the valve body is held at a position on an opening side of a fully closed position as the predetermined position. It is said that the flow control valve is driven and controlled.
[0018]
According to this configuration, when the initialization process is performed at the time of starting the engine, the valve body of the flow control valve is located at a position closer to the fully open position, which is the reference position of the initialization process, than the fully closed position. become. Therefore, the time from when the initialization process is started to when the valve body contacts the stopper at the fully open position can be reduced, and the time required for the initialization process can be further reduced.
[0019]
According to a third aspect of the present invention, in the cooling device for an internal combustion engine according to the second aspect, the stop-time control means drives the flow control valve such that the valve body is held at the fully open position as the predetermined position. It is said to be controlled.
[0020]
According to this configuration, since the movement of the valve body to the predetermined position is performed in parallel with the initialization processing, there is no need to further move the valve body to the predetermined position after the initialization processing is completed. . Therefore, the time required for the initialization processing can be significantly reduced.
[0021]
According to a fourth aspect of the present invention, in the cooling device for an internal combustion engine according to any one of the first to third aspects, when the engine is stopped, the valve body is not held at the predetermined position. Means for starting the engine, and setting the drive command value in the initialization processing to the maximum value of the valve element on condition that the fact that the valve element is not held at the predetermined position is stored and held in the storage means. Setting means for setting a value corresponding to the amount of displacement or more.
[0022]
According to this configuration, even if the valve body of the flow control valve is not held at the predetermined position when the engine is stopped for some reason, such as when the engine is immediately started after the engine stop operation of the internal combustion engine, the engine is not started. In this initialization processing, the valve element can be reliably brought into contact with the stopper to execute the processing.
[0023]
According to a fifth aspect of the present invention, in the cooling device for an internal combustion engine according to any one of the first to fourth aspects, the flow control valve is opened and closed by using a stepping motor as a drive source.
[0024]
As described above, in the configuration in which the stepping motor is used as the drive source of the flow control valve, the step-out occurs during the operation of the engine, and the position between the position of the valve body corresponding to the drive command value and the actual position is changed. In some cases.
[0025]
According to the fifth aspect of the present invention, in such a configuration in which the stepping motor is employed as the drive source of the flow control valve, the adverse effect due to the step-out can be suitably suppressed, and the time required for the initialization process can be shortened as much as possible. Thus, the warm-up property can be improved.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram schematically showing a configuration of a cooling device for a vehicle-mounted internal combustion engine according to the present embodiment.
[0027]
This cooling device converts a water pump 10, a cooling passage 11 including a water jacket formed around a combustion chamber (not shown) of the internal combustion engine 1 and the like, a radiator 12, and cooling water flowing into the radiator 12 according to the opening degree. The flow control valve 14 is provided with an electronic control device 40 for controlling the opening degree of the flow control valve 14, and the like. The electronic control unit 40 integrally controls various engine controls such as fuel injection control and ignition timing control in addition to cooling water temperature control. The electronic control unit 40 includes a memory 41 for storing an execution program and an execution result of these controls.
[0028]
The water pump 10 is drivingly connected to an output shaft (not shown) of the internal combustion engine 1 and is driven by rotation of the output shaft. The outlet of the water pump 10 is connected to the inlet of the cooling passage 11. On the other hand, the outlet of the cooling passage 11 is connected to the radiator 12 via the radiator passage 15. Further, a downstream portion of the radiator 12 in the radiator passage 15 is connected to the flow control valve 14. Further, the flow control valve 14 is connected to the water pump 10 via a pump passage 16.
[0029]
When the water pump 10 is driven, the cooling water discharged from the water pump 10 is introduced into the cooling passage 11 and used for cooling the engine body. The cooling water whose temperature has increased due to the cooling of the engine body is introduced into the radiator passage 15 when the flow control valve 14 is opened, and is cooled when passing through the radiator 12. The cooling water whose temperature has been lowered by the cooling by the radiator 12 is returned to the water pump 10 again through the pump passage 16.
[0030]
The outlet of the cooling passage 11 is connected to the radiator 12 via a radiator passage 15 and also connected to a pump passage 16 via a heater passage 18 provided with a heater 19 for heating a vehicle compartment on the way. ing.
[0031]
Further, the outlet of the cooling passage 11 is connected to a flow control valve 14 via a bypass passage 17 that bypasses the radiator 12. Therefore, of the cooling water that has passed through the cooling passage 11, except for the amount introduced into the radiator 12 and the heater 19, the cooling water passes through the bypass passage 17 and the flow control valve 14 and is returned to the water pump 10 through the pump passage 16. .
[0032]
Next, the configuration of the flow control valve 14 will be described with reference to FIG.
The flow control valve 14 has a first valve portion 21 for metering cooling water introduced from the radiator passage 15 through the pump passage 16 into the water pump 10, and a water pump 10 through the bypass passage 17 and the pump passage 16. And a second valve portion 22 for metering the cooling water introduced into the cooling device. The first valve portion 21 includes a first valve body 211 and a first valve seat 212 on which the valve body 211 is separated and seated. On the other hand, the second valve portion 22 is configured to include, in addition to the first valve body 211, a second valve body 221 and a second valve seat 222 on which the valve body 221 is detached and seated.
[0033]
A port 51 forming a part of the radiator passage 15, a port 52 forming a part of the bypass passage 17, and a port 53 forming a part of the heater passage 18 are formed in the body 25 of the flow control valve 14, respectively. Have been. Further, a joining chamber 32 to which the pump passage 16 is connected is formed inside the body 25, and the radiator passage 15 and the bypass passage 17 are respectively opened to the joining chamber 32.
[0034]
The first valve seat 212 is formed on the periphery of the opening of the radiator passage 15 that opens into the merging chamber 32. When the first valve body 211 is detached from and seated on the first valve seat 212, the junction chamber 32 and the radiator passage 15 are communicated and blocked. On the other hand, the second valve seat 222 is formed on the periphery of the opening of the bypass passage 17 that opens into the merging chamber 32. The first valve body 211 and the second valve body 221 are separated from and seated on the second valve seat 222, so that the junction chamber 32 and the bypass passage 17 are communicated and blocked.
[0035]
A valve shaft 26 is provided on the body 25 so as to be able to reciprocate in the axial direction, and a first valve body 211 and a second valve body 221 are attached at substantially the center thereof. When the valve shaft 26 is displaced in the axial direction, the distance between each of the valve bodies 211 and 221 and the corresponding valve seats 212 and 222 is changed, and the first valve portion 21 and the second valve portion 22 are changed. Is changed.
[0036]
The flow control valve 14 is provided with a four-phase excitation type stepping motor 24 that adjusts the opening of each of the valve portions 21 and 22 as a driving source. The stepping motor 24 is disposed above the valve shaft 26 in the axial direction, and a driving nut 29 is screwed to the driving shaft 28. A retainer 27 whose upper part can be engaged with a driving nut 29 is attached to one end (the upper end in FIG. 2) of the valve shaft 26. A spring 30 is provided between the retainer 27 and the driving nut 29. The retainer 27 and the valve shaft 26 are biased by the biasing force of the spring 30 away from the drive nut 29.
[0037]
On the other hand, a spring 31 is provided between the first valve body 211 and a part of the body 25 that reciprocally supports the opposite end (the lower end in FIG. 2) of the valve shaft 26. . Due to the urging force of the spring 31, the first valve body 211 is urged to the side away from the first valve seat 212 and to the side close to the second valve seat 222.
[0038]
A bearing 33 is formed inside the body 25 and extends from the inner surface to the center to support the valve shaft 26 in a reciprocating manner. When the drive shaft 28 rotates and the drive nut 29 is displaced upward in the axial direction of the drive shaft 28, the valve shaft 26 is displaced upward in the axial direction. As a result, as shown in FIG. 2, the second valve body 221 comes into contact with the lower end surface of the bearing 33. As a result, the displacement of the valve shaft 26 further upward in the axial direction is restricted, and the first valve body 211 stops at the position furthest away from the first valve seat 212. As described above, in the present embodiment, the bearing 33 functions as a stopper for regulating the displacement of the first valve body 211 and holding the first valve body 211 at the fully open position.
[0039]
In the following, the position of the first valve element 211 when the second valve element 221 is in contact with the bearing 33 is referred to as a “fully open position”, and the state of the first valve section 21 is described below. Is referred to as a “fully open state”.
[0040]
Next, a change in the opening degree of the flow control valve 14 based on the driving of the stepping motor 24 will be described with reference to FIG. FIG. 3 is a graph showing the relationship between the drive signal output to the stepping motor 24 (the amount of increase or decrease in the number of motor steps) and the radiator flow rate passing through the radiator passage 15 and the bypass flow rate passing through the bypass passage 17.
[0041]
When the first valve portion 21 is in the fully opened state, a drive signal for reducing the number of motor steps of the stepping motor 24 is output, and when the drive shaft 28 rotates in a predetermined direction around the axis based on the drive signal, the drive signal is output. The drive nut 29 is displaced downward in the axial direction of the drive shaft 28 by a predetermined amount according to the rotation angle. When the driving nut 29 is displaced in this manner, the retainer 27 and the valve shaft 26 are urged downward in the axial direction by the elastic force of the spring 30. Therefore, the first valve body 211 is displaced axially downward together with the valve shaft 26 and the like, comes close to the first valve seat 212, and separates from the second valve seat 222. As a result, the opening of the first valve portion 21 gradually decreases.
[0042]
On the other hand, the second valve body 221 comes closer to the valve seat 222 as the first valve body 211 moves away from the second valve seat 222 in this way. As a result, although the opening degree of the second valve portion 22 is increased once the first valve body 211 is separated from the second valve seat 222, the second valve body 221 is opened by the second valve seat 222. , And decreases again as the distance becomes closer.
[0043]
For example, if the current number of motor steps is “α” and the target number of motor steps is “β (<α)”, the number of motor steps decreases by an amount corresponding to “β−α”. This is manipulated to As a result, the opening of the first valve portion 21 gradually decreases as the number of motor steps decreases, and as shown in FIG. 3, the radiator flow rate decreases.
[0044]
On the other hand, when the current motor step number α is relatively large (for example, in the case of “α> NS2” in FIG. 3), the second valve portion 22 Is gradually increased. Accordingly, as shown in FIG. 3, the bypass flow rate gradually increases. On the other hand, when the current number of motor steps α is relatively small (for example, in the case of “α <NS1” in FIG. 3), the opening degree of the second valve portion 22 decreases with a decrease in the number of motor steps. It gradually decreases. Therefore, the bypass flow rate gradually decreases. Further, when the current motor step number α takes an intermediate value (for example, in the case of “NS1 ≦ α ≦ NS2” in FIG. 3), the second valve unit does not operate even if the motor step number decreases. The opening of the valve 22 hardly changes, so that the bypass flow rate is kept substantially constant.
[0045]
On the other hand, a driving signal for increasing the number of motor steps of the stepping motor 24 is output, and when the driving shaft 28 of the stepping motor 24 rotates in a direction opposite to the predetermined direction based on the driving signal, a position corresponding to the rotation angle is generated. The driving nut 29 is displaced upward in the axial direction of the driving shaft 28 with a certain amount. When the driving nut 29 is displaced in this manner, the valve shaft 26 is displaced upward in the axial direction together with the retainer 27 with the displacement. Therefore, the first valve body 211 comes close to the second valve seat 222 and separates from the first valve seat 212. As a result, the opening of the first valve portion 21 gradually increases. When the second valve body 221 contacts the bearing 33, further displacement of the second valve body 221, the first valve body 211, and the valve shaft 26 is restricted, and the first valve portion 21 Is fully opened again.
[0046]
The driving of the stepping motor 24 is basically controlled based on the deviation between the current motor step number and the target motor step number as described above. For example, one of the excitation circuits of each phase may be used. When an abnormality such as disconnection occurs, the following abnormal processing is performed.
[0047]
That is, in this abnormal time process, the stepping motor 24 is used as a DC motor, and the driving torque thereof is adjusted so that the thrust generated in the valve shaft 26 according to the driving torque and the urging force of the spring 31 are balanced. . Thus, the valve shaft 26, in other words, each of the valve bodies 211 and 221 is stopped at a predetermined position, and the first valve portion 21 and the second valve portion 22 can be held at a predetermined opening degree. Become. By executing such an abnormal time process, although the control accuracy is reduced, the opening degree of the flow control valve 14 can be controlled even when the stepping motor 24 is abnormal.
[0048]
In the apparatus according to the present embodiment, when the engine is started, the stepping motor 24 is driven to open based on a predetermined drive command value, so that the second valve body 221 contacts the bearing 33 and the first valve body 211 is closed. By regulating the displacement, a process for specifying the fully open position of the valve body 211, that is, an initialization process is executed. Hereinafter, a series of processes including the initialization process performed at the time of starting the engine is referred to as “start-time valve driving process”.
[0049]
Further, in the apparatus according to the present embodiment, in order to minimize the time required for the initialization processing at the time of starting the engine, the initialization processing is executed at the time of stopping the engine, and the first valve is provided after the completion of the processing. The control for holding the body 211 at the fully open position (referred to as “stop valve driving process”) is also executed.
[0050]
Hereinafter, the stop-time valve drive process and the start-time valve drive process will be described with reference to FIGS. 4 and 5.
The flowchart of FIG. 4 shows a processing procedure of the stop valve drive processing. A series of processes shown in FIG. 3 is repeatedly executed by the electronic control device 40 at a predetermined control cycle.
[0051]
In this series of processing, first, it is determined whether or not the internal combustion engine 1 has transitioned from the operating state to the stopped state between the previous control cycle and the current control cycle (step S100). In this determination, for example, it is determined that the engine has been stopped when the engine rotation speed has decreased to a predetermined speed or less. Here, when it is determined that the internal combustion engine 1 is in the operating state (step S100: NO), this series of processing is temporarily ended. In this case, in this case, the target value of the engine cooling water temperature is calculated based on the engine load and the like through a processing routine different from the present processing, so that the current engine cooling water temperature matches the target value. Then, the opening of the flow control valve 14 is feedback-controlled.
[0052]
On the other hand, when it is determined that the internal combustion engine 1 has transitioned from the operating state to the stopped state (step S100: YES), a drive signal for executing the initialization processing, specifically, a stepping motor The amount of increase when increasing the number of motor steps of 24 is calculated (step S110).
[0053]
Here, the step number increase amount ΔNS sufficient to bring the second valve body 221 into contact with the bearing 33 to reliably displace the first valve body 211 from the current position to the fully open position is shifted to the engine stop state. The motor step number of the stepping motor 24 at the time of the calculation is calculated as an initial value.
[0054]
For example, when the number of motor steps required to shift the first valve portion 21 from the fully closed state to the fully open state is “NSMAX” and the current number of motor steps is “NSNOW”, the step number increase amount ΔNS is as follows. It is calculated through the following equation (1).
[0055]
ΔNS ← NSMAX−NSNOW + k1 (1)
Here, "k1" is an increase in the number of steps to absorb the stepping motor 24 and to surely shift the first valve portion 21 to the fully open state even if a slight step-out occurs in the stepping motor 24. This is a correction amount for the large amount of ΔNS.
[0056]
When the step number increase amount ΔNS is calculated in this way, an initialization process is executed based on the step number increase amount ΔNS (step S120).
By performing the initialization processing in this manner, the first valve body 211 and the second valve body 221 are displaced together with the valve shaft 26, and the second valve body 221 comes into contact with the bearing 33 and the first valve body 221 contacts the bearing 33. The valve body 211 comes to a standstill at the fully open position. Thereafter, the position of the first valve body 211 is controlled so that the position of the first valve body 211 is maintained at the fully open position. Therefore, when the initialization process is completed and the position of the first valve body 211 is held at the fully open position when the engine is stopped, the first valve body 211 is held at the fully open position when the engine is started thereafter. Can be regarded as being done.
[0057]
As described above, when the internal combustion engine 1 shifts to the stop state, the power supply from the battery to the electronic control unit 40 is performed through a processing routine different from this processing until a predetermined period elapses from the shift. To be continued. The electronic control unit 40 performs post-processing such as writing the execution results of various controls during the operation of the engine into the memory 41 until the power supply period after the stop of the engine elapses. The execution results and the like written in the memory 41 in this manner are stored and held until the next engine operation. Each of the processes in steps S110 and S120 is executed during the power supply period after the engine stops.
[0058]
Next, it is determined whether or not the initialization processing has been completed (step S130). To be precise, in the process of step S130, the second valve body 221 is brought into contact with the bearing 33 by performing the initialization process when the engine is stopped, and the first valve body 211 is held at the fully open position. It is determined whether the state has been reached. If it is determined that the initialization process for stopping the engine has not been completed, that is, if the first valve body 211 is not held at the fully open position, the initialization process incomplete flag is set to “ "On" is set, and the result is stored in the memory 41 of the electronic control unit 40 (step S150). Therefore, if the power supply period of the electronic control unit 40 when the engine is stopped has elapsed before the initialization process is completed, the initialization process incomplete flag is set to “ON”.
[0059]
An example in which the power supply period of the electronic control unit 40 when the engine is stopped while the initialization processing incomplete flag is set to “ON” without being set to “OFF” as described above is, for example, There are cases such as the following.
[0060]
-When the execution period of the initialization process has been extended for some reason after the engine stopped.
-When the engine is restarted before the initialization process is completed after the engine is stopped.
-When the voltage of the battery drops and the stepping motor 24 cannot be driven.
[0061]
-When the memory 41 is initialized by replacing the battery after the engine is stopped.
-When the initialization process has never been executed after returning from the process when the stepping motor 24 is abnormal.
[0062]
On the other hand, when the initialization process at the time of engine stop is completed and it is determined that the first valve body 211 is held at the fully open position, the initialization process incomplete flag is set to “OFF”. The result is stored in the memory 41 of the electronic control unit 40 (step S140).
[0063]
As described above, after the initialization process is completed when the engine is stopped, and after the initialization process incomplete flag is turned on / off based on the determination result as to whether or not the first valve body 211 is held at the fully open position. This series of processing is temporarily ended.
[0064]
Next, the startup valve driving process will be described with reference to FIG. The flowchart of FIG. 5 shows a processing procedure of the valve driving process at the time of starting. A series of processes shown in FIG. 3 is repeatedly executed by the electronic control device 40 at a predetermined control cycle.
[0065]
In this series of processing, first, it is determined whether or not the current control cycle is at the time of starting the engine (step S200). Here, when it is determined that the engine is being started (step S200: YES), first, the storage contents of the memory 41 are read, and whether or not the initialization process incomplete flag is set to “ON” is determined. Is determined (step S210). Here, when the initialization process incomplete flag is “ON”, that is, when the engine is stopped prior to the current engine start, the initialization process is not completed, and the position of the first valve body 211 is undefined. In this case, the step number increase amount ΔNS in the initialization processing is set to the maximum increase amount ΔNSMAX (step S220). Here, even if the first valve body 211 is in the fully closed position, the second valve body 221 is brought into contact with the bearing 33 through the initialization processing, and the maximum increase amount ΔNSMAX is determined by the first valve body 211. Is set to a size that can be reliably displaced to the fully open position. The maximum increase amount ΔNSMAX is calculated based on, for example, the following equation (2).
[0066]
ΔNSMAX ← NSMAX + k2 (2)
k2 ≧ 0
Here, "NSMAX" is the number of motor steps required to shift the first valve section 21 from the fully closed state to the fully open state, as in the case of the equation (1). Further, even when the relative position of the first valve body 211 with respect to the first valve seat 212 is slightly changed due to, for example, vibration or the like, “k2” is absorbed and absorbed by the first valve body 211. This is a correction amount for the maximum increase amount ΔNSMAX for surely displacing the 211 to the fully open position.
[0067]
On the other hand, when the initialization process incomplete flag is “OFF”, that is, when the engine is stopped prior to the current start of the engine, the initialization process has been completed, and the first valve body 211 is held at the fully open position. In this case, the step number increase amount ΔNS in the initialization processing is set to the minimum increase amount ΔNSMIN (step S240). Here, the minimum increase amount ΔNSMIN is calculated based on, for example, the following equation (3).
[0068]
ΔNSMIN ← k3 (3)
k3 ≧ 0
Here, “k3” is a case where the distance between the first valve body 211 and the first valve seat 212 slightly changes due to vibration or the like, similarly to the correction amount k2 in the above equation (2). However, the size is set such that it can be absorbed and the first valve body 211 can be reliably displaced to the fully open position. Accordingly, ΔNSMIN (= k3) is set to a larger value as it is assumed that the relative position change of the first valve body 211 due to the vibration or the like described above is larger. Conversely, if the relative position change of the first valve body 211 can be almost ignored, ΔNSMIN (= k3) can be set to “0”.
[0069]
In addition, when the initialization process incomplete flag is “off”, the step number increase amount ΔNS is set relatively small, and compared with the case where the flag is “on”, the engine start time is not increased. The time required for the initialization process is greatly reduced. Therefore, the first valve portion 21 can be shifted from the fully open state to the fully closed state as soon as possible when starting the engine, and good warm-up properties can be secured.
[0070]
On the other hand, if it is determined in step S200 that the engine is not being started (step S200: NO), then, if the process returns from the above-described abnormal process, the process returns to the initialization process. Is determined (step S230). Here, if the initialization process has already been performed after the return from the abnormal time process (step S230: NO), this series of processes is temporarily ended. On the other hand, if the initialization process has not been executed after the return from the abnormal-time process, the step number increase amount ΔNS is set to the maximum increase amount ΔNSMAX to execute the same process (step S250).
[0071]
In this way, when the step number increase amount NS is set based on the setting state of the initialization process incomplete flag and the like, the initialization process is executed based on the step number increase amount NS (step S260). Then, this series of processing is temporarily ended.
[0072]
According to the cooling device according to the present embodiment in which the initialization process is performed on the flow control valve 14 in such a manner, the following operational effects can be obtained.
[0073]
In the cooling device according to the present embodiment, when the engine is stopped, the flow control valve 14 (the stepping motor 24) is drive-controlled, so that the first valve body 211 is held at the fully open position. Therefore, in the initialization processing accompanying the engine start, this is executed under the situation where the current position of the first valve body 211 is grasped. Further, since the initialization process is performed even when the engine is stopped, the positioning accuracy when the first valve body 211 is held at the fully open position is extremely high. As a result, even when the first valve body 211 is displaced during the engine operation, such as a position displacement due to the step-out of the stepping motor 24, the first valve body 211 is corrected after the correction. It can be accurately held at the fully open position. Therefore, it is possible to prevent the drive operation of the flow rate control valve from being performed more than necessary during the initialization process at the time of starting the engine, and it is possible to improve the warm-up property. Furthermore, deformation and damage of the bearing 33 functioning as a stopper due to unnecessary driving operation of the flow control valve and reduction in durability of the stepping motor 24 can be suppressed.
[0074]
In the device according to the present embodiment, the first valve body 211 is held at the fully open position after the initialization process is completed when the engine is stopped, but the holding position is not necessarily the fully open position. There is no. In short, if the initialization process is performed when the engine is stopped, the initialization process can be performed after accurately grasping the current position of the first valve body 211 when the engine is started. The required time can be reduced. Here, in the apparatus according to the present embodiment, since the holding position after the completion of the initialization process is set to the fully open position, the initialization process and the process of moving the first valve body 211 to a predetermined position are performed. It will be done in parallel. Therefore, it is not necessary to further move the valve body to the predetermined position after the completion of the initialization processing, and the time required for the initialization processing can be greatly reduced.
[0075]
Furthermore, in the device according to the present embodiment, when the engine is stopped, the initialization process is not completed, and when the first valve body 211 is not held at the fully open position, the initialization process incomplete flag is set to “ON”. You have set. When the engine is started, the drive command value in the initialization process, that is, the step number increase amount ΔNS is set to a value equal to or greater than the maximum increase amount ΔNSMAX, provided that the initialization process incomplete flag is set to “ON”. (= NSMAX + k2). Therefore, even when the first valve body 211 of the flow control valve 14 is not held at the fully open position when the engine is stopped, such as when the engine is immediately stopped after the engine stop operation, the second process is performed in the initialization process at the time of engine start. The first valve body 211 can be moved to the fully open position by reliably bringing the valve body 221 into contact with the stopper.
[0076]
In particular, although the flow control valve 14 is adapted to be opened and closed by using the stepping motor 24 as a drive source, even with such a flow control valve, it is possible to suitably suppress the adverse effect due to step-out of the stepping motor. Thus, the time required for the initialization process can be shortened as much as possible to improve the warm-up property.
[0077]
As described above, the embodiment of the present invention has been described, but the embodiment can also change its configuration and control structure as follows.
-Although the stepping motor is used as a drive source of the flow control valve 14, for example, a DC motor, an actuator using air pressure or the like can be used as the drive source.
[0078]
When the engine is stopped, the first valve body 211 is held at the fully open position after the initialization processing is completed. For example, after the initialization processing is completed, the first valve body 211 is specified at a position other than the fully open position. It may be moved to a position and held at the same position.
[0079]
When the initialization process incomplete flag is “ON”, the step number increase amount ΔNS in the initialization process is set to the maximum increase amount ΔNSMAX. For example, the current motor step number NSNOW is stored and held. If so, the step number increase amount ΔNS may be set through the above equation (1). That is, as described above, the initialization process incomplete flag is set to “ON” when the engine is stopped and the engine start operation is performed again before the initialization process is completed, or when the battery voltage decreases. Then, the driving of the stepping motor 24 is stopped. In such a case, since the current motor step number NSNOW is stored and held, the step number increase amount ΔNS can be set through the above (1). By setting the step number increase amount ΔNS in this way, it is possible to reduce the chance of the initialization process being lengthened, and to improve the durability of the stepping motor 24.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing the configuration of a cooling device for an internal combustion engine.
FIG. 2 is a sectional view showing a configuration of a flow control valve.
FIG. 3 is a graph showing a relationship between the number of motor steps and a radiator flow rate and a bypass flow rate.
FIG. 4 is a flowchart showing a processing procedure of a stop-time valve driving process.
FIG. 5 is a flowchart showing a processing procedure of a startup valve driving process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 10 ... Water pump, 11 ... Cooling passage, 12 ... Radiator, 14 ... Flow control valve, 15 ... Radiator passage, 16 ... Pump passage, 17 ... Bypass passage, 18 ... Heater passage, 19 ... Heater, 21 first valve portion, 22 second valve portion, 24 stepping motor, 25 body, 26 valve shaft, 27 retainer, 28 drive shaft, 29 driving nut, 30 spring , 31 ... Spring, 32 ... Merging chamber, 33 ... Bearing, 211 ... First valve body, 212 ... First valve seat, 221 ... Second valve body, 222 ... Second valve seat, 40 ... Electronic control Devices (stop control means, storage means, setting means), 41 ... memory, 51-53 ... ports.

Claims (5)

A flow control valve for controlling the flow rate of the engine cooling water passing through the radiator of the internal combustion engine, and opening the flow control valve based on a predetermined drive command value until the displacement of the valve body is regulated by the stopper; In the cooling device of the internal combustion engine, which executes an initialization process for specifying the fully open position of the valve body by driving when starting the engine,
The internal combustion engine according to claim 1, further comprising: a stop-time control unit configured to execute the initialization process when the engine is stopped and to control the driving of the flow control valve so that the valve body is held at a predetermined position after the initialization process is completed. Engine cooling system. The cooling device for an internal combustion engine according to claim 1,
The internal combustion engine cooling device, wherein the stop-time control means drives and controls the flow control valve such that the valve body is held at a position on the opening side of the fully closed position as the predetermined position. The cooling device for an internal combustion engine according to claim 2,
The cooling device for an internal combustion engine, wherein the stop-time control means controls the drive of the flow control valve so that the valve body is maintained at the full open position as the predetermined position. The cooling device for an internal combustion engine according to any one of claims 1 to 3,
Storage means for storing and holding when the valve is not held at the predetermined position when the engine is stopped,
At the time of starting the engine, the drive command value in the initialization processing is equal to or more than the maximum displacement of the valve body on condition that the fact that the valve body is not held at the predetermined position is stored and held in the storage means. Setting means for setting the value to a value corresponding to the amount of the internal combustion engine. The cooling device for an internal combustion engine according to any one of claims 1 to 4,
The cooling device for an internal combustion engine, wherein the flow control valve is driven to open and close by using a stepping motor as a drive source.

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