JP2011007068A - Cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device capable of appropriately cooling an internal combustion engine.SOLUTION: The device includes a circulation means 3 which can cool an internal combustion engine 2 by circulating cooling medium in the internal combustion engine 2, a detection means 4 which can detect a temperature of the cooling medium and a control means 5 which estimates the temperature of the cooling medium in a temperature estimation object position 7 having a temperature higher than the temperature detection position 6 by the detection means 4 on the basis of a change amount dthw/dt per unit time of a detected value thw of temperature by the detection means 4 and circulates the cooling medium by the circulation means 3 when the estimated value Tmax of the temperature is a specific value set in advance or higher.

Description

  The present invention relates to a cooling device, and more particularly to a cooling device for an internal combustion engine that can suitably estimate the temperature of a cooling medium at a position distant from a temperature detection means.

  As a conventional cooling device, there is a cooling device for cooling an internal combustion engine. As such a conventional cooling device, for example, an electric water pump device for a vehicle described in Patent Document 1 includes a motor that drives a water pump that circulates cooling water as a cooling medium between an engine and a radiator. And a temperature sensor that detects the temperature of the cooling water, and a control device that controls the motor based on the detected temperature of the cooling water. Then, the control device provided in the electric water pump device for a vehicle performs motor stop or deceleration when the temperature of the cooling water detected by the temperature sensor is equal to or lower than a predetermined value, and the detected temperature of the cooling water is equal to or higher than the predetermined value. In this case, by driving or accelerating the motor, warming up of the engine is promoted by not circulating the cooling water through the engine while the temperature of the cooling water is low.

JP 2002-161748 A

  However, in the electric water pump device for a vehicle described in Patent Document 1 described above, it is determined whether or not to start the circulation of the cooling water based only on the sensor detection value obtained by simply detecting the temperature of the cooling water during the circulation stop by the temperature sensor. Thus, for example, depending on the mounting position of the temperature sensor, it is not possible to detect the coolant temperature at the center in the cylinder head of the engine where the coolant temperature tends to be relatively high. When the temperature is large, a sudden temperature rise of the cooling water cannot be detected, and the cooling water may boil. For this reason, in the electric water pump device for vehicles described in patent documents 1, there was a possibility that more effective engine cooling might be inhibited.

  Accordingly, an object of the present invention is to provide a cooling device that can properly cool an internal combustion engine.

  In order to achieve the above object, a cooling device according to the present invention comprises a circulating means for circulating a cooling medium inside an internal combustion engine to cool the internal combustion engine, a detecting means capable of detecting the temperature of the cooling medium, Based on the change amount per unit time of the detected value of the temperature by the detecting means, the temperature of the cooling medium at the temperature estimation target position higher than the temperature detecting position by the detecting means is estimated, and the estimated value of the temperature And a control means for circulating the cooling medium by the circulation means when the value is equal to or greater than a predetermined value set in advance.

  In the cooling device, the control unit may be configured to start the circulation of the cooling medium by controlling the circulation unit when the estimated value of the temperature reaches the specified value.

  Further, in the cooling device, the circulation means includes a jacket provided inside the cylinder head of the internal combustion engine and capable of cooling the cylinder head by flowing the cooling medium, and the temperature estimation target position is You may comprise so that it may be located in the center part of the said jacket whose temperature is higher than a detection position.

  In the cooling device, the control unit may be configured to estimate a temperature of the cooling medium at the temperature estimation target position based on a moving average value of a change amount per unit time of the detection value. Good.

  In the cooling device, the control unit may be configured to set a calculation period of the moving average value based on a change amount of the detection value per unit time.

  In the cooling device, the control unit sets the calculation period on the side where the change amount per unit time of the detection value is large relatively short, and the change amount per unit time of the detection value is small. You may comprise so that the said calculation period by the side may be set comparatively long.

  In the cooling device, the control unit sets a coefficient for calculating the estimated value of the temperature from the amount of change of the detected value per unit time based on the amount of change of the detected value per unit time. You may comprise.

  With the cooling device according to the present invention, the internal combustion engine can be appropriately cooled.

FIG. 1 is a schematic configuration diagram of an engine cooling device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a relationship between the engine output and the maximum coolant temperature deviation width in the engine cooling device according to the embodiment of the present invention. FIG. 3 is a flowchart illustrating an example of cooling water circulation start determination control of the engine cooling device according to the embodiment of the present invention. FIG. 4 is a time chart for explaining the relationship between the estimated value of the maximum coolant temperature at the temperature estimation target position of the engine cooling device according to the embodiment of the present invention and the actual measured value.

  Hereinafter, embodiments of a cooling device according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

(Embodiment)
FIG. 1 is a schematic schematic configuration diagram of an engine cooling device according to an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the engine output and the maximum coolant temperature deviation width in the engine cooling device according to the embodiment of the present invention. FIG. 3 is a flowchart illustrating an example of cooling water circulation start determination control of the engine cooling device according to the embodiment of the present invention, and FIG. 4 is a temperature estimation target of the engine cooling device according to the embodiment of the present invention. It is a time chart explaining the relationship between the estimated value and actual value of the cooling water maximum water temperature of a position.

  As shown in FIG. 1, an engine cooling device 1 as a cooling device according to the present embodiment is applied to an engine 2 as an internal combustion engine and cools the engine 2. The engine cooling device 1 includes an engine cooling water circulation device 3 as circulation means, a temperature sensor 4 as detection means, and a control device 5 as control means.

  Here, the engine 2 is mounted and driven in a vehicle such as a passenger car or a truck to generate engine torque as engine torque, and the generated engine torque is applied to the wheels of the vehicle. In short, the engine 2 is a heat engine that outputs thermal energy generated by burning fuel in the combustion chamber 21 in the form of mechanical energy such as torque. The engine 2 is, for example, an intake stroke while a piston provided in a reciprocating motion in a cylinder bore communicating with the combustion chamber 21 is reciprocated twice in accordance with combustion of a mixture of air and fuel in the combustion chamber 21. This is a so-called four-cycle engine that performs a series of four strokes including a compression stroke, an expansion stroke, and an exhaust stroke. In this embodiment, the engine 2 is a reciprocating spark ignition internal combustion engine using gasoline as fuel, but the engine 2 is not limited to this. The engine 2 may be, for example, a spark ignition internal combustion engine using LPG or alcohol as fuel, a so-called rotary spark ignition internal combustion engine, or a diesel engine.

  The engine 2 includes, for example, a fuel injection device (not shown), an ignition device, a throttle valve device, and the like. These devices are electronic devices (not shown) that are configured around a microcomputer and can control each part of the engine 2. It is electrically connected to a control unit (ECU: Electronic Control Unit) and controlled by this ECU. The ECU determines the fuel injection amount (in the engine 2) based on the engine operating state such as the intake air amount, intake air temperature, intake pressure, throttle opening, accelerator opening, engine speed, engine cooling water temperature detected by various sensors. Fuel injection period), injection timing, ignition timing, etc. are determined, and the fuel injection valve and ignition plug of the engine 2 are driven to execute fuel injection and ignition, thereby controlling the operation of the engine 2 and serving as an output shaft The engine torque generated in the crankshaft can be controlled. Note that the control device 5 of the engine cooling device 1 described later may be configured integrally with this ECU.

  The engine cooling water circulation device 3 cools the engine 2 with this cooling water by circulating cooling water as a cooling medium inside the engine 2. The engine coolant circulation device 3 includes a circulation pipe 31, a water jacket 32 as a jacket, a radiator 33, and an electric water pump 34. The engine cooling water circulation device 3 circulates the cooling water between the water jacket 32 and the radiator 33 inside the engine 2 through the circulation pipe 31 by driving the electric water pump 34 for cooling the engine 2. Let

  The circulation pipe 31 forms a part of a cooling water passage through which cooling water can flow. The circulation pipe 31 is composed of various pipes through which cooling water can flow. The circulation pipe 31 has one end connected to the cooling water inlet of the water jacket 32 and the other end connected to the cooling water discharge port of the water jacket 32.

  The circulation pipe 31 is provided with a radiator 33 and an electric water pump 34 on its path. The circulation pipe 31 is provided with, for example, a water jacket 32, a radiator 33, and an electric water pump 34 in this order along the circulation direction of the cooling water. Accordingly, the circulation pipe 31 can circulate the cooling water between the water jacket 32 and the radiator 33 by driving the electric water pump 34 and flowing the cooling water inside. In other words, the circulation pipe 31 and the water jacket 32 form a cooling water circulation path through which the cooling water circulates.

  The water jacket 32 forms a part of a cooling water passage through which cooling water can flow. The water jacket 32 is provided inside the cylinder head 22 of the engine 2. The water jacket 32 is provided in the cylinder head 22 so as to cover the periphery of the wall surfaces of the plurality of combustion chambers 21 formed in the cylinder head 22 of the engine 2. The water jacket 32 is formed as a hollow space inside the cylinder head 22, and cooling water is supplied to the hollow space via the circulation pipe 31. The water jacket 32 can cool the cylinder head 22 when the supplied cooling water flows inside and the heat is exchanged between the cooling water and the cylinder head 22.

  Here, the cylinder head 22 of the engine 2 is connected to one end (upper part) of a cylinder block (not shown) in which a cylinder bore of the engine 2 is formed, and a plurality of cylinder heads 22 communicate with the respective combustion chambers 21 inside. An intake port and a plurality of exhaust ports are formed. The water jacket 32 is provided inside the cylinder head 22 so as to cover the periphery of the ceiling portion, the intake port, the exhaust port, and the like of each combustion chamber 21.

  The engine coolant circulation device 3 also includes a water jacket (not shown) inside the cylinder block of the engine 2. That is, the engine coolant circulation device 3 may include a water jacket provided in the cylinder block separately from the water jacket 32 provided in the cylinder head 22. The water jacket provided in the cylinder block is provided inside the cylinder block so as to cover the periphery of the plurality of cylinder bores corresponding to the respective combustion chambers 21.

  The radiator 33 is provided on the circulation pipe 31 and cools the cooling water. For example, the radiator 33 cools the cooling water circulating through the circulation pipe 31 by exchanging heat between the outside air and the cooling water. For example, the radiator 33 may cool the cooling water by the traveling wind of the vehicle, or may include a radiator fan (not shown) that forcibly sends outside air to the main body of the radiator 33 and the wind that the radiator fan sends out. The cooling water may be cooled by

  The electric water pump 34 feeds the cooling water in a predetermined circulation direction in the circulation pipe 31. The electric water pump 34 is electrically connected to the control device 5, and the drive is controlled by the control device 5. The electric water pump 34 includes, for example, a water pump main body and a motor that drives the water pump main body, and the flow rate of the cooling water circulating through the circulation pipe 31 is controlled by the control device 5 so that the number of rotations of the motor is controlled. Can be adjusted.

  Therefore, when the electric water pump 34 is driven in the engine cooling water circulation device 3, the cooling water in the circulation pipe 31 starts to flow and circulates through the circulation pipe 31. The cooling water circulating through the circulation pipe 31 is introduced from the circulation pipe 31 into the water jacket 32 through the cooling water inlet. When the cooling water is introduced into the water jacket 32, the water jacket 32 contacts the cylinder head 22 to exchange heat with the cylinder head 22, thereby cooling the vicinity of the cylinder head 22. Then, when the heat is exchanged with the cylinder head 22 and the vicinity of the cylinder head 22 is cooled, the cooling water that has received the heat and rises in temperature is discharged from the water jacket 32 to the circulation pipe 31 through the cooling water discharge port. And is introduced into the radiator 33. The cooling water introduced into the radiator 33 is heat-exchanged with the outside air by the radiator 33 and cooled by radiating the received heat to the outside air. After the temperature is lowered, the cooling water is again introduced into the water jacket 32. When the driving of the electric water pump 34 is stopped, the engine cooling water circulation device 3 stops the flow of the cooling water flowing and circulating through the circulation pipe 31 and the cooling of the engine 2 is stopped.

  The temperature sensor 4 can detect the temperature of the cooling water circulating through the circulation pipe 31 and the water jacket 32. The temperature sensor 4 detects the temperature of the cooling water at a predetermined detection position 6. The temperature sensor 4 is electrically connected to the control device 5 and outputs a detection result, that is, a detected value of the temperature of the cooling water detected at the detection position 6 to the control device 5.

  Here, the predetermined detection position 6 where the temperature sensor 4 detects the temperature of the cooling water is set to be located at the outer edge portion in the water jacket 32. In other words, the detection position 6 is located in the water jacket 32 on the side close to the outside air where the temperature sensor 4 is relatively easy to install, in other words, on the outer edge on the side close to the outer surface of the cylinder head 22. ing. For example, in the inline 4-cylinder engine 2 as illustrated in FIG. 1, the detection position 6 is in the vicinity of the outer surface of the cylinder head 22 in the water jacket 32 and in the vicinity of the cooling water discharge port of the water jacket 32. It is set to be located. That is, the temperature sensor 4 of the present embodiment detects the temperature of the cooling water at the detection position 6 located near the outer surface of the cylinder head 22 and near the cooling water discharge port of the water jacket 32.

  The control device 5 controls the driving of the engine coolant circulation device 3 based on the detection result of the temperature sensor 4. As described above, the control device 5 is electrically connected to the electric water pump 34 and electrically connected to the temperature sensor 4. The control device 5 controls the driving of the electric water pump 34 based on the temperature of the coolant detected by the temperature sensor 4, thereby controlling the ON / OFF of the engine coolant circulation device 3 and the coolant circulating through the circulation pipe 31. The flow rate control can be executed. The control device 5 can turn on the engine coolant circulation device 3 (drive state) by setting the electric water pump 34 to the drive state, that is, the coolant circulates in the circulation pipe 31 and enters the water jacket 32. Thus, the engine 2 can be cooled. On the other hand, the control device 5 can set the electric water pump 34 to the stopped state so that the engine cooling water circulation device 3 can be turned off (stopped), that is, the cooling water circulation is stopped and the engine 2 is cooled. Can be stopped. In addition, this control apparatus 5 may be comprised integrally in ECU (not shown) as mentioned above.

  By the way, in such an engine cooling device 1, for example, when the warm-up is promoted, that is, the temperature of the cooling water during circulation of the cooling water is simply detected based on only the sensor detection value detected by the temperature sensor 4. When determining the circulation start, for example, the cylinder head 22 of the engine 2 in which the coolant temperature tends to be relatively high depending on the attachment position of the temperature sensor 4, that is, the temperature detection position 6 of the temperature sensor 4. The cooling water temperature in the inner central part cannot be detected. As a result, for example, when the intake air amount is large and the engine load is large, a sudden temperature rise of the cooling water cannot be detected and the cooling water may boil. is there. In this case, the engine cooling device 1 may hinder more effective engine cooling.

  Therefore, in the engine cooling device 1 of the present embodiment, the control device 5 cools the temperature estimation target position 7 higher than the detection position 6 based on the amount of change per unit time in the detected value of the coolant temperature by the temperature sensor 4. By estimating the temperature of the water and controlling the drive of the engine cooling water circulation device 3 based on the estimated value of the temperature of the cooling water at the temperature estimation target position 7, for example, the cooling water circulation start timing can be optimized. As a result, the engine 2 is properly cooled. That is, the engine cooling device 1 estimates the temperature of the engine high-temperature part where the control device 5 is located away from the detection position 6 of the temperature sensor 4 and the cooling water may reach the maximum water temperature while the cooling water circulation is stopped. By accurately estimating the temperature of the cooling water at the target position 7, the driving of the engine cooling water circulation device 3 is controlled based on the estimated value of the temperature of the cooling water at the temperature estimation target position 7, thereby Boiling is prevented and proper engine cooling is achieved.

  Specifically, as shown in FIG. 1, the engine cooling device 1 of the present embodiment is functionally conceptual in terms of a pump control unit 50, a change rate calculation unit 51, a moving average value calculation unit 52, and a temperature estimation. A value calculation unit 53 and a comparison determination unit 54 are provided in the control device 5.

  Here, the control device 5 is configured around a microcomputer, and includes a processing unit 5a, a storage unit 5b, and an input / output unit 5c, which are connected to each other and can exchange signals with each other. A drive circuit (not shown) for driving each part of the engine cooling device 1 and the various sensors described above are connected to the input / output unit 5c. The input / output unit 5c inputs and outputs signals to and from these sensors and the like. To do. The storage unit 5b stores a computer program for controlling each unit of the engine cooling device 1. The storage unit 5b is a hard disk device, a magneto-optical disk device, a nonvolatile memory such as a flash memory (a storage medium that can only be read such as a CD-ROM), or a RAM (Random Access Memory). A volatile memory or a combination thereof can be used. The processing unit 5a includes a memory (not shown) and a CPU (Central Processing Unit), and includes at least the above-described pump control unit 50, change speed calculation unit 51, moving average value calculation unit 52, temperature estimated value calculation unit 53, A comparison / determination unit 54 is provided. Various controls by the control device 5 are performed by the processing unit 5a reading the computer program into a memory incorporated in the processing unit 5a based on the detection results of the sensors provided in the respective units, and depending on the calculation results. It is executed by sending a control signal. At that time, the processing unit 5a appropriately stores a numerical value in the middle of the calculation in the storage unit 5b, and takes out the stored numerical value and executes the calculation. In addition, when controlling each part of this engine cooling device 1, you may control by the dedicated hardware different from the control apparatus 5 instead of the said computer program.

  The pump control unit 50 controls the driving of the electric water pump 34 of the engine coolant circulating apparatus 3. As described above, the pump control unit 50 controls the driving of the electric water pump 34 to perform the ON / OFF control of the engine coolant circulation device 3 and the flow rate control of the coolant circulating through the circulation pipe 31.

  The change speed calculation unit 51 calculates a change speed (rising speed / falling speed) dthw / dt of the detected value (output value) thw of the temperature of the cooling water by the temperature sensor 4. The change rate dthw / dt of the temperature detection value thw of the cooling water by the temperature sensor 4 corresponds to the amount of change per unit time of the detection value thw of the temperature of the cooling water at the detection position 6 by the temperature sensor 4. This corresponds to the time differential value of the detected value thw of the temperature of the cooling water at the detection position 6 by the temperature sensor 4. The change rate dthw / dt of the detection value thw calculated by the change rate calculation unit 51 is a change gradient (up / down gradient) with respect to the time axis of the detected value thw of the coolant temperature at the detection position 6 by the temperature sensor 4. Is also equivalent. The change speed calculation unit 51 calculates the change speed dthw / dt of the detected value thw based on the detected value thw of the coolant temperature at the detection position 6 detected by the temperature sensor 4.

  The moving average value calculation unit 52 calculates the moving average value of the change speed dthw / dt of the detection value thw in a predetermined calculation period. The moving average value calculation unit 52 is based on the change speed dthw / dt of the detection value thw calculated by the change speed calculation unit 51, in the calculation period ba from the calculation start time point a to the calculation end time point b (for example, the current time point). The moving average value of the change speed dthw / dt is calculated.

  The temperature estimated value calculation unit 53 estimates the temperature of the cooling water at the temperature estimation target position 7 based on the change rate dthw / dt of the detection value thw calculated by the change rate calculation unit 51. In the present embodiment, the temperature estimated value calculation unit 53 calculates the temperature of the cooling water at the temperature estimation target position 7 based on the moving average value of the change speed dthw / dt of the detection value thw calculated by the moving average value calculation unit 52. presume.

  Here, the temperature estimation target position 7 where the temperature estimated value calculation unit 53 estimates the temperature of the cooling water is a position different from the detection position 6 of the cooling water temperature by the temperature sensor 4, and is higher than the detection position 6. Is the position. The temperature estimation target position 7 is located at the center of the water jacket 32 that is hotter than the detection position 6. The temperature estimation target position 7 is located closer to the center of the water jacket 32 than the detection position 6 located at the outer edge of the water jacket 32. In other words, the temperature estimation target position 7 is located in the water jacket 32 on the side farther from the outside air than the detection position 6, in other words, on the central portion on the side farther from the outer surface of the cylinder head 22 than the detection position 6. is doing. For example, in the in-line four-cylinder engine 2 as illustrated in FIG. 1, the temperature estimation target position 7 is between the two combustion chambers 21 inside the four combustion chambers (cylinders) 21 in the water jacket 32. It is set to be located in the center part of. Since the temperature estimation target position 7 is set so as to be located in the central portion between the two combustion chambers 21, the cooling water at the temperature estimation target position 7 tends to be relatively hot, The temperature of the cooling water at this temperature estimation target position 7 tends to be the highest water temperature.

  That is, the temperature estimated value calculation unit 53 of the present embodiment detects the estimated value Tmax of the temperature of the cooling water at the temperature estimation target position 7 where the temperature of the cooling water is likely to be relatively high and is likely to be the maximum water temperature. Estimation is based on the change rate dthw / dt of the value thw. Here, it is assumed that the estimated value Tmax of the coolant temperature at the temperature estimation target position 7 estimated by the temperature estimated value calculation unit 53 is the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7.

  Here, FIG. 2 is a diagram illustrating an example of the relationship between the engine output and the maximum coolant temperature deviation width in the engine cooling apparatus 1. In FIG. 2, the horizontal axis is the engine output Pw [kW], and the vertical axis is the temperature estimation target position 7 for the detected value thw when the detected value thw of the coolant temperature at the detection position 6 reaches 80 ° C. The deviation width [° C.] of the actual measured value Tmax (actually measured) of the maximum water temperature of the cooling water. The relationship between the engine output and the coolant maximum water temperature divergence width in FIG. 2 exemplifies a case where the engine 2 is a 1.5 L inline 4-cylinder engine and the ambient temperature is −7 ° C.

  FIG. 2 shows a deviation width [Tmax (actual measurement) −thw] between the detected value thw of the cooling water temperature at the detection position 6 and the actual measured value Tmax (actual measurement) of the maximum coolant temperature at the temperature estimation target position 7. As shown, the engine output Pw tends to change substantially proportionally. That is, the deviation width [Tmax (actual measurement) −thw] and the engine output Pw are substantially proportional (linear), and the ratio between the change amount of the engine output Pw and the variation amount of the deviation width [Tmax (actual measurement) −thw]. Is almost constant.

  Therefore, the relational expression of the deviation width [Tmax−thw] between the detected value thw of the temperature of the cooling water at the detection position 6 and the estimated value Tmax of the maximum water temperature of the cooling water at the temperature estimation target position 7 is, for example, It can be expressed by the following mathematical formula (1). In this formula (1), thw is a detected value of the temperature of the cooling water at the detection position 6, Tmax is an estimated value of the maximum water temperature of the cooling water at the temperature estimation target position 7, Pw is the engine output, and α and β are predetermined coefficients. For example, for each engine 2 to which the engine cooling device 1 is applied, the value is preliminarily adapted in accordance with the coolant temperature actually measured in a test or the like.

  Assuming that the engine output Pw is correlated with the change (rise) speed dthw / dt of the detected value thw of the coolant temperature at the detection position 6, the estimated value of the maximum coolant temperature at the temperature estimation target position 7 is assumed. The prediction formula of Tmax can be expressed by, for example, Formula (2) shown in the following Equation 2. In this mathematical formula (2), α ′ and β ′ are predetermined coefficients, and the coolant temperature measured in a test or the like for each engine 2 to which the engine cooling device 1 is applied, for example, similar to the coefficients α and β described above. It is a value that is pre-adapted according to.

  The temperature estimated value calculation unit 53 calculates the detected value thw of the temperature of the cooling water at the detection position 6 detected by the temperature sensor 4 and the change rate dthw / dt of the detection value thw calculated by the change rate calculation unit 51 using the formula (2 ), It is possible to calculate the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7, and estimate and predict the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7. Is possible.

  Here, the temperature estimated value calculation unit 53 of the present embodiment further cools the temperature estimation target position 7 using the moving average value of the change speed dthw / dt of the detection value thw calculated by the moving average value calculation unit 52 described above. By calculating the estimated value Tmax of the maximum water temperature, the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 is estimated and predicted more accurately.

  That is, the temperature estimated value calculation unit 53 of the present embodiment calculates, for example, the following equation (3) expressed by the following Equation 3 to the detected value thw of the coolant temperature at the detection position 6 detected by the temperature sensor 4 and the moving average: By substituting the moving average value of the change speed dthw / dt in the calculation period ba from the calculation start time point a calculated by the value calculation unit 52 to the calculation end time point b (for example, the current time point), the temperature estimation target position 7 The estimated value Tmax of the maximum coolant temperature can be estimated and predicted.

  Thereby, the temperature estimated value calculation unit 53 can smooth the change rate dthw / dt of the detection value thw. For example, convection of cooling water or lateral G in the water jacket 32 according to the behavior of the vehicle As a result, the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 can be calculated more accurately. Further, the coefficients α ′ and β ′ are coefficients set from the coolant temperature measured in accordance with the variation of the change rate dthw / dt in a test or the like for each engine 2 to which the engine cooling device 1 is applied, for example. The estimated value Tmax calculated based on Equation (3) can be appropriately followed with respect to the coolant temperature change when the engine output Pw fluctuates.

  The comparison determination unit 54 performs various determinations by comparing various numerical values. The comparison determination unit 54 compares at least the estimated value Tmax of the coolant maximum water temperature at the temperature estimation target position 7 calculated by the temperature estimated value calculation unit 53 with a preset specified value, and the cooling water at the temperature estimation target position 7 is compared. It is determined whether the estimated value Tmax of the maximum water temperature is equal to or higher than a specified value. Here, the preset specified value is, for example, a value corresponding to the warm-up end temperature, and is a value corresponding to at least a temperature lower than the temperature at which the cooling water as the cooling medium boils.

  The comparison determination unit 54 performs ON / OFF determination of the engine coolant circulation apparatus 3 based on a comparison result between the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 and the specified value. When the comparison determination unit 54 determines that at least the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 is equal to or greater than the specified value, the pump that turns the engine coolant circulation device 3 to the ON state (drive state). A drive command is output to the pump control unit 50. More specifically, the comparison / determination unit 54 predicts that the cooling water is likely to boil when the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 reaches a specified value, and circulates the engine coolant. A pump drive command for starting the circulation of the cooling water by controlling the device 3 is generated and output to the pump control unit 50. The determination for setting the engine coolant circulation device 3 to the OFF state (stop state) may be performed by various known determinations.

  Then, the pump control unit 50 sets the electric water pump 34 to the driving state based on the pump driving command generated by the comparison / determination unit 54, thereby turning the engine cooling water circulation device 3 to the ON state (driving state). Circulation is started and cooling of the engine 2 is started by the water jacket 32.

  In the engine cooling device 1 configured as described above, the control device 5 determines the cooling water at the temperature estimation target position 7 based on the moving average value of the change speed dthw / dt of the detection value thw, here the change speed dthw / dt. Since the temperature of the estimated value Tmax of the maximum water temperature is estimated, regardless of the temperature detection position 6 of the temperature sensor 4, the temperature becomes higher than the detection position 6 while the cooling water circulation is stopped (that is, during warm-up promotion). The temperature of the cooling water at the temperature estimation target position 7 can be accurately estimated. For example, a sudden rise in the temperature of the cooling water can be reliably detected. When the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 is equal to or greater than a preset specified value, the engine cooling device 1 causes the engine coolant circulating device 3 to circulate the coolant. By doing so, for example, it is possible to optimize the cooling water circulation start timing, and to reliably prevent the cooling water from boiling, and thus the engine 2 can be appropriately cooled.

  Here, in order to prevent boiling of the cooling water, for example, when a specified value set with respect to the sensor detection value thw of the temperature sensor 4 is given in order to determine the start of circulation of the cooling water, that is, When the specified value is set to a relatively low temperature, boiling of the cooling water can be prevented, but the cooling water temperature at which the circulation of the cooling water starts is relatively low. There is a possibility that the effect of promoting warm-up of the engine 2 by not circulating the cooling water to the engine 2 in a low state may be reduced.

  However, as described above, the engine cooling device 1 according to the present embodiment is configured so that when the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 reaches the specified value, the control device 5 Since the engine cooling water circulation device 3 is controlled to start circulation of the cooling water, the boiling of the cooling water is prevented, and the cooling water is not circulated through the engine 2 in a state where the temperature of the cooling water is low. It can suppress that the effect of warming-up promotion is reduced. That is, the engine cooling device 1 can achieve both prevention of boiling of cooling water and promotion of warm-up of the engine 2, and can cool the engine 2 more appropriately.

  Here, as shown in FIG. 1, the engine cooling device 1 of the present embodiment may further include a calculation period setting unit 55 and a coefficient setting unit 56 in the control device 5.

  The calculation period setting unit 55 sets the calculation period of the moving average value of the change rate dthw / dt of the detection value thw. The calculation period setting unit 55 calculates the moving average value of the change speed dthw / dt from the calculation start time point a to the calculation end time point b (for example, the current time point) based on the change speed dthw / dt calculated by the change speed calculation unit 51. The calculation period ba is variably set. For example, the calculation period setting unit 55 changes the calculation period ba based on the change speed dthw / dt by changing the calculation start time point a according to the change speed dthw / dt.

  Specifically, the calculation period setting unit 55 sets the calculation period ba on the side where the change rate dthw / dt is large relatively short, and the calculation period ba on the side where the change rate dthw / dt is small. Is set relatively long. That is, the calculation period setting unit 55 sets the calculation period ba relatively shorter as the change speed dthw / dt of the detection value thw is faster, and the calculation period b− as the change speed dthw / dt of the detection value thw is lower. Set a relatively long. The moving average value calculation unit 52 calculates the moving average value of the change speed dthw / dt in the calculation period ba set by the calculation period setting unit 55 according to the change speed dthw / dt. As a result, the engine cooling device 1 can reliably detect a sudden rise in the temperature of the cooling water, and starts circulation of the cooling water by the engine cooling water circulation device 3 with good followability to a sudden change in the temperature of the cooling water. can do.

  The coefficient setting unit 56 sets coefficients α ′ and β ′ in Expression (3) when calculating the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 from the moving average value. The coefficient setting unit 56 variably sets the coefficients α ′ and β ′ in Expression (3) based on the change speed dthw / dt calculated by the change speed calculation unit 51. That is, the coefficient setting unit 56 changes the coefficients α ′ and β ′ in the equation (3) according to the change speed dthw / dt.

  For example, the coefficient setting unit 56 maps or formulates the coefficients α ′ and β ′ in advance in correspondence with the change speed dthw / dt by a test or the like, and calculates the change speed based on the coefficient map or formula. Coefficients α ′ and β ′ corresponding to the change speed dthw / dt are calculated from the change speed dthw / dt calculated by the unit 51. The estimated temperature calculation unit 53 calculates the maximum cooling water at the temperature estimation target position 7 based on the formula (3) to which the coefficients α ′ and β ′ set by the coefficient setting unit 56 according to the change speed dthw / dt are applied. An estimated value Tmax of the water temperature is calculated. As a result, the engine cooling device 1 can detect, for example, the temperature estimation target position 7 by the temperature estimation value calculation unit 53 caused by the difference between the thermal resistance of the member near the detection position 6 and the thermal resistance of the member near the temperature estimation target position 7. As a result, the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 can be calculated more accurately.

  Next, an example of the cooling water circulation start determination control of the engine cooling device 1 according to the present embodiment will be described with reference to the flowchart of FIG. Note that these control routines are repeatedly executed at a control cycle of several ms to several tens of ms.

  In the cooling water circulation start determination control illustrated in FIG. 3, first, the change speed calculation unit 51 of the control device 5 provided in the engine cooling device 1 detects the temperature of the cooling water at the current detection position 6 detected by the temperature sensor 4. Based on thw and the past detection value thw stored in the storage unit 5b, the change rate dthw / dt of the detection value thw is calculated (S100).

  Next, the calculation period setting unit 55 and the coefficient setting unit 56 of the control device 5 calculate the moving average value calculation period b− based on the change rate dthw / dt of the detection value thw calculated by the change rate calculation unit 51 in S100. a, Coefficients α ′ and β ′ of Expression (3) are set (S102).

  Next, the moving average value calculation unit 52 of the control device 5 determines the change rate dthw / dt of the detection value thw calculated by the change rate calculation unit 51 in S100 or the past change rate dthw / dt stored in the storage unit 5b. Based on the above, the moving average value of the change speed dthw / dt in the calculation period ba set by the calculation period setting unit 55 in S102 according to the change speed dthw / dt is calculated (S104).

  Next, the temperature estimated value calculation unit 53 of the control device 5 adds the coefficient α ′, β ′ set by the coefficient setting unit 56 according to the change speed dthw / dt in S102 to Formula (3), in S100. The detected temperature thw of the cooling water at the current detection position 6 detected by the temperature sensor 4 and the moving average value of the change speed dthw / dt calculated by the moving average value calculating unit 52 in S104 are substituted, and the temperature estimation target An estimated value Tmax of the maximum coolant temperature at position 7 is calculated (S106).

  Next, the comparison / determination unit 54 of the control device 5 compares the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 calculated by the temperature estimation value calculation unit 53 in S106 with a preset specified value, It is determined whether the estimated value Tmax of the maximum coolant temperature at the estimation target position 7 is equal to or greater than a specified value (S108).

  When the comparison determination unit 54 determines that the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 is smaller than the specified value (S108: No), the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 is The determination of S108 is repeatedly executed until it is determined that the value is equal to or greater than the specified value.

  If the comparison determination unit 54 determines that the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 is equal to or greater than the specified value (S108: Yes), it generates a pump drive command and outputs it to the pump control unit 50. Based on this, the pump control unit 50 of the control device 5 sets the electric water pump 34 to the driving state, starts circulating the cooling water, starts cooling the engine 2 with the water jacket 32 (S110), and sets the current control cycle. End and shift to the next control cycle.

  FIG. 4 is a time chart for explaining an example of the relationship between the estimated value Tmax (predicted) of the maximum coolant temperature at the temperature estimation target position 7 of the engine cooling device 1 according to the embodiment of the present invention and the measured value Tmax (measured). It is. In FIG. 4, the horizontal axis is the time axis, and the vertical axis is the temperature of the cooling water. FIG. 4 exemplifies a case where the engine 2 is a 1.5 L in-line four-cylinder engine and the ambient temperature is 25 ° C. In the figure, a thin solid line thw (actual measurement) indicates cooling water at the detection position 6. The detected temperature value, the thick solid line Tmax (actually measured) indicates the actually measured value of the maximum coolant temperature at the temperature estimation target position 7, and the thick dashed line Tmax (predictive value) indicates the estimated value of the maximum coolant temperature at the temperature estimated target position 7. ing. 4 can be expressed by the following mathematical formula (4) in which α ′ = 23 and β ′ = 10 are substituted into the mathematical formula (3).

  As is clear from this figure, the estimated value Tmax (prediction) of the maximum coolant temperature at the temperature estimation target position 7 calculated as described above is the actual measured value Tmax of the maximum coolant temperature at the temperature estimation target position 7. It can be understood that this is almost following (actual measurement). Then, at time T1, it is determined that the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 is equal to or greater than the specified value, the electric water pump 34 is driven, and the coolant is started to circulate. When the cooling of the engine 2 is started, it can be understood that the actual measured value Tmax (actual measurement) of the maximum coolant temperature at the temperature estimation target position 7 is decreased.

  According to the engine cooling device 1 according to the embodiment of the present invention described above, the cooling water can be circulated inside the engine 2 to cool the engine 2 and the temperature of the cooling water can be detected. Temperature sensor 4 and a temperature estimation temperature higher than temperature detection position 6 by temperature sensor 4 based on change rate dthw / dt which is a change amount per unit time of temperature detection value thw of cooling water by temperature sensor 4 Control that estimates the temperature of the cooling water at the target position 7 and causes the engine cooling water circulation device 3 to circulate the cooling water when the estimated value Tmax of the temperature of the cooling water at the temperature estimation target position 7 is greater than or equal to a preset specified value. Device 5.

  Therefore, in the engine cooling device 1, the control device 5 estimates the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7 based on the change rate dthw / dt of the detected value thw, and the estimated value Tmax is a specified value. Since the cooling water is circulated by the engine cooling water circulation device 3 in the above case, the cooling water circulation start timing can be optimized, and the boiling of the cooling water can be reliably prevented. The engine 2 can be cooled appropriately.

  Further, the engine cooling device 1 does not provide a sensor for detecting the temperature of the cooling water at the temperature estimation target position 7 separately from the temperature sensor 4, and uses the estimated value Tmax of the maximum coolant temperature at the temperature estimation target position 7. Since it can be estimated, an increase in the number of parts constituting the engine cooling device 1 can be suppressed, and an increase in manufacturing cost of the engine cooling device 1 can be suppressed. Furthermore, the engine cooling device 1 can estimate the temperature of the cooling water at an arbitrary temperature estimation target position 7 away from the detection position 6 of the temperature sensor 4 and also can create a complicated control map for determining the cooling water circulation start. Therefore, it can be easily applied to an existing engine cooling device.

  Furthermore, according to the engine cooling device 1 according to the embodiment of the present invention described above, the control device 5 determines that the engine temperature when the estimated value Tmax of the coolant temperature at the temperature estimation target position 7 reaches the specified value. The cooling water circulation device 3 is controlled to start the circulation of the cooling water. Therefore, the engine cooling device 1 can achieve both prevention of boiling of cooling water and promotion of warm-up of the engine 2, and can cool the engine 2 more appropriately.

  Furthermore, according to the engine cooling device 1 according to the embodiment of the present invention described above, the engine cooling water circulation device 3 is provided inside the cylinder head 22 of the engine 2 and cools the cylinder head 22 by flowing the cooling water. The possible water jacket 32 is provided, and the temperature estimation target position 7 is located at the center of the water jacket 32 that is hotter than the detection position 6. Therefore, the engine cooling device 1 uses the control device 5 to detect the estimated value Tmax of the temperature of the cooling water at the temperature estimation target position 7 where the temperature of the cooling water is likely to be relatively high and is likely to be the maximum water temperature. Can be estimated based on the moving average value of the change speed dthw / dt.

  Furthermore, according to the engine cooling device 1 according to the embodiment of the present invention described above, the control device 5 cools the temperature estimation target position 7 based on the moving average value of the change speed dthw / dt of the detection value thw. Estimate water temperature. Therefore, the engine cooling device 1 can relax the detection error of the coolant temperature, and as a result, the estimated value Tmax of the coolant temperature at the temperature estimation target position 7 can be calculated more accurately.

  Furthermore, according to the engine cooling device 1 according to the embodiment of the present invention described above, the control device 5 sets the calculation period of the moving average value based on the change rate dthw / dt of the detection value thw. Therefore, the engine cooling device 1 can calculate the moving average value of the change speed dthw / dt in the calculation period set according to the change speed dthw / dt.

  Further, according to the engine cooling device 1 according to the embodiment of the present invention described above, the control device 5 sets the calculation period on the side where the change rate dthw / dt of the detection value thw is large relatively short, The calculation period on the side where the change rate dthw / dt of the detection value thw is small is set relatively long. Therefore, the engine cooling device 1 can reliably detect a sudden rise in the temperature of the cooling water, and starts circulation of the cooling water by the engine cooling water circulation device 3 with good followability to a sudden change in the temperature of the cooling water. be able to.

  Furthermore, according to the engine cooling device 1 according to the embodiment of the present invention described above, the control device 5 determines from the change rate dthw / dt of the detection value thw based on the change rate dthw / dt of the detection value thw. Here, coefficients α ′ and β ′ for calculating the estimated temperature value from the moving average value of the change speed dthw / dt of the detection value thw are set. Therefore, the engine cooling device 1 can detect the temperature estimation target position 7 by the temperature estimated value calculation unit 53 caused by the difference between the thermal resistance of the member near the detection position 6 and the thermal resistance of the member near the temperature estimation target position 7, for example. The estimation error of the cooling water temperature can be relaxed, and as a result, the estimated value Tmax of the maximum cooling water temperature at the temperature estimation target position 7 can be calculated more accurately.

  The cooling device according to the above-described embodiment of the present invention is not limited to the above-described embodiment, and various changes can be made within the scope described in the claims.

  In the above description, the temperature estimation target position has been described as being located in the center of the jacket, but is not limited thereto. Further, although the control means has been described as setting the calculation period of the moving average value based on the change amount of the detection value per unit time, the present invention is not limited to this. In addition, the control unit has been described as setting a coefficient for calculating the estimated value of the temperature of the cooling medium at the temperature estimation target position from the moving average value based on the change amount of the detected value per unit time. Not limited to.

  In the above description, the control unit has been described as estimating the temperature of the cooling medium at the temperature estimation target position based on the moving average value of the change amount per unit time of the detected value of the cooling medium temperature by the detection unit. However, the present invention is not limited to this, and the temperature of the cooling medium at the temperature estimation target position may be simply estimated based on the amount of change per unit time in the detected value of the temperature of the cooling medium by the detection unit. Even in this case, the cooling device of the present invention can properly cool the internal combustion engine. In this case, the cooling device of the present invention may not include the above-described moving average value calculation unit 52, calculation period setting unit 55, and the like.

  As described above, the cooling device according to the present invention can appropriately cool the internal combustion engine, and is suitable for application to various cooling devices for cooling the internal combustion engine.

1 Engine cooling device (cooling device)
2 Engine (Internal combustion engine)
3 Engine cooling water circulation device (circulation means)
4 Temperature sensor (detection means)
5 Control device (control means)
6 Detection position 7 Temperature estimation target position 22 Cylinder head 31 Circulation piping 32 Water jacket (jacket)
33 Radiator 34 Electric Water Pump 50 Pump Control Unit 51 Change Speed Calculation Unit 52 Moving Average Value Calculation Unit 53 Temperature Estimated Value Calculation Unit 54 Comparison Determination Unit 55 Calculation Period Setting Unit 56 Coefficient Setting Unit

Claims (7)

Circulation means capable of cooling the internal combustion engine by circulating a cooling medium inside the internal combustion engine;
Detection means capable of detecting the temperature of the cooling medium;
Based on the amount of change per unit time of the temperature detection value by the detection means, the temperature of the cooling medium at a temperature estimation target position higher than the temperature detection position by the detection means is estimated, and the temperature estimation A control means for circulating the cooling medium by the circulation means when the value is equal to or greater than a predetermined value set in advance,
Cooling system. The control means starts the circulation of the cooling medium by controlling the circulation means when the estimated value of the temperature reaches the specified value.
The cooling device according to claim 1. The circulation means has a jacket provided inside the cylinder head of the internal combustion engine and capable of cooling the cylinder head by flowing the cooling medium,
The temperature estimation target position is located in a central portion of the jacket that is hotter than the detection position.
The cooling device according to claim 1 or 2. The control means estimates a temperature of the cooling medium at the temperature estimation target position based on a moving average value of a change amount per unit time of the detection value.
The cooling device according to any one of claims 1 to 3. The control means sets a calculation period of the moving average value based on an amount of change per unit time of the detection value.
The cooling device according to claim 4. The control means sets the calculation period on the side where the change amount per unit time of the detection value is large relatively short, and sets the calculation period on the side where the change amount per unit time of the detection value is small. Set relatively long,
The cooling device according to claim 5. The control means sets a coefficient for calculating the estimated value of the temperature from the amount of change per unit time of the detected value based on the amount of change per unit time of the detected value.
The cooling device according to any one of claims 1 to 6.

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