JP2017166406A - Cooling pump control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a temperature of an internal combustion engine to an appropriate range by appropriately controlling a variation in flow rate of a cooling pump in regard to a change in heat release value of an internal combustion engine.SOLUTION: A cooling pump control device 100 for controlling a flow rate of a cooling pump 104 for circulating cooling water to an internal combustion engine 102 comprises a controller 202 getting a target flow rate corresponding to a present heat release value of the internal combustion engine to control a flow rate of the cooling pump to cause it to become the target flow rate. The controller is constituted in such a way that the flow rate is reduced at a low average reduction speed as the heat release value before changing of the heat release value is higher when the flow rate of the cooling pump is decreased as the changing in reduction of the heat release value of the internal combustion engine occurs.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cooling pump control device that controls the operation of a cooling pump that circulates cooling water of an internal combustion engine.

  Conventionally, cooling water of an internal combustion engine is circulated by an electric water pump (hereinafter referred to as a cooling pump), and the number of rotations of the cooling pump is increased as the temperature of the cooling water increases, thereby increasing the flow of circulating cooling water. A device for controlling the cooling water temperature within a predetermined range is known.

  Conventionally, a map indicating the number of revolutions of the cooling pump (target number of revolutions) to be set according to the torque and the number of revolutions of the engine is previously determined and stored, and the map according to the current operating state of the engine A cooling water control device is known in which the target rotational speed of the cooling pump is determined and the determined target rotational speed is set in the cooling pump (Patent Document 1). In this cooling water control apparatus, for example, the circulating speed of the cooling water can be controlled in accordance with the heat generation amount of the engine determined from the engine torque and the rotational speed.

  However, in the above conventional cooling water control device, the target rotational speed of the cooling pump is determined in a step shape according to the operating state of the engine. Therefore, when the torque or rotational speed of the engine suddenly increases or decreases, the engine body is configured. Before the engine combustion heat generation increase / decrease changes appear in the cooling water after a delay time corresponding to the heat capacity of the structure (cylinder case, etc.), the number of revolutions of the cooling pump increases or decreases all at once, and the engine is overcooled. In addition, the cooling capacity may be lowered due to insufficient cooling or local boiling of the cooling water, which may cause undesirable events such as fuel consumption deterioration.

JP 2008-144673 A

  From the above background, it is desired to appropriately control the change in the flow rate of the cooling pump with respect to the change in the heat generation amount of the internal combustion engine to control the temperature of the internal combustion engine within an appropriate range.

One aspect of the present invention is a cooling pump control device that controls the flow rate of a cooling pump that circulates cooling water in an internal combustion engine. The cooling pump control device includes a controller that determines a target flow rate according to a current heat generation amount of the internal combustion engine and controls the flow rate of the cooling pump so as to be the target flow rate, and the controller includes the internal combustion engine When the flow rate of the cooling pump is decreased along with the decrease in the heat generation amount, the flow rate is decreased at a smaller average decrease rate as the heat generation amount before the heat generation amount change is larger.
According to another aspect of the present invention, when the controller decreases the flow rate of the cooling pump in accordance with a decrease in the heat generation amount of the internal combustion engine, the temperature of the cooling water before the change in the heat generation amount is further increased. The higher the flow rate, the lower the flow rate is.
According to another aspect of the present invention, when the controller decreases the flow rate of the cooling pump as the heat generation amount of the internal combustion engine decreases, the amount of change in the heat generation amount exceeds a predetermined amount. When the flow rate is decreased, the flow rate is decreased at a predetermined average decrease rate.
According to another aspect of the present invention, the controller is configured to decrease the flow rate along a decreasing curve expressed by an exponential function, and the calorific value before the decrease in the calorific value of the internal combustion engine is large. The time constant of the decreasing curve is increased, and the flow rate is decreased at a small average decreasing rate.
According to another aspect of the present invention, the controller is configured to decrease the flow rate along a decreasing curve expressed by an exponential function, and a temperature of the cooling water before a decrease change in the heat generation amount of the internal combustion engine. The higher the is, the larger the time constant of the decreasing curve is, and the flow rate is decreased at a smaller average decreasing rate.
According to another aspect of the present invention, when the controller decreases the flow rate of the cooling pump as the heat generation amount of the internal combustion engine decreases, the amount of change in the heat generation amount exceeds a predetermined amount. When the time constant is set to a predetermined value, the flow rate is decreased at a predetermined average decrease rate.
According to another aspect of the present invention, the heat generation amount of the internal combustion engine is determined from the intake air amount of the internal combustion engine.

It is a figure which shows an example of a structure of the internal combustion engine system to which the cooling pump control apparatus which concerns on one Embodiment of this invention was applied. It is a figure which shows the structure of the cooling pump control apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the target flow rate map which the cooling pump control apparatus shown in FIG. 2 uses. It is a figure which shows an example of the target reduction parameter (PM) map which the cooling pump control apparatus shown in FIG. 2 uses. It is a figure for demonstrating the method to determine the time constant which is a target reduction parameter value from the target reduction PM map shown in FIG. FIG. 3 is an explanatory diagram for explaining the operation of the cooling pump control device shown in FIG. 2 over time. It is a flowchart which shows the procedure of operation | movement of the cooling pump control apparatus shown in FIG.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating an example of a configuration of an internal combustion engine system to which a cooling pump control device according to an embodiment of the present invention is applied. The cooling pump control apparatus 100 controls, for example, the flow rate of the cooling pump 104 that circulates the cooling water in the internal combustion engine 102 (that is, the cooling water discharge amount (the amount of cooling water discharged per unit time)).

  The cooling water discharged from the cooling pump 104 flows into the internal combustion engine 102 from the cooling water inlet 108 through the pipe 106, cools a cylinder (not shown) and the like inside the internal combustion engine, and then from the cooling water outlet 110. Flows out. The cooling water that has flowed out of the cooling water outlet 110 flows through the pipe 112, splits the radiator 114 and the pipe 116, joins again, passes through the pipe 118, and flows into the cooling pump 104. As a result, the cooling water discharged from the cooling pump 104 to the pipe 106 flows through the internal combustion engine 102 and then flows from the pipe 118 to the cooling pump 104 so that the cooling water circulates.

  The cooling pipe 112 is provided with a water temperature sensor 120 that detects the temperature of the cooling water, and a sensor signal output from the water temperature sensor 120 is input to the cooling pump control device 100. Further, a pipe 122 that is a part of the cooling water circulation pipe connected to the radiator 114 is provided with a thermostat 124 that opens the water channel and guides the cooling water into the radiator 114 when a predetermined water temperature is reached. Thereby, when the cooling water is lower than the predetermined water temperature, the cooling water is cooled by the circulation path passing through the pipe 116, and when the cooling water temperature becomes equal to or higher than the predetermined water temperature, the thermostat 124 is opened and the cooling water is supplied by the radiator 114. Will also be cooled.

  An intake pipe 130 that introduces air for fuel combustion into a cylinder (not shown) of the internal combustion engine 102 includes an intake valve 132 that adjusts the intake air amount, and an intake air that detects the air amount that passes through the intake valve 132. A quantity sensor 134. The opening degree of the intake valve 132 is, for example, the opening degree of an accelerator (not shown) operated by a driver by an engine control ECU (Electronic Control Unit) (not shown) that controls fuel combustion in the internal combustion engine 102. And so on. Further, the sensor signal output from the intake sensor 134 is input to the cooling pump control device 100.

  FIG. 2 is a diagram showing a configuration of the cooling pump control apparatus 100 according to an embodiment of the present invention. This cooling pump control device (hereinafter also referred to as a pump control device) 100 can be realized as an ECU different from the engine control ECU or as a part of an ECU such as the engine control ECU.

  The pump control apparatus 100 includes an input interface (input INF) 200 for receiving sensor signals from the intake sensor 134 and the water temperature sensor 120, a current intake air amount acquired from the sensor signal of the intake sensor 134, and a water temperature sensor. The controller 202 that controls the flow rate of the cooling pump 104 based on the current cooling water temperature acquired from the 120 sensor signals, the storage device 204 that stores data necessary for processing in the controller 202, and the controller 202 outputs. And an output interface (output INF) 206 for outputting a signal for controlling the pump flow rate to the cooling pump 104. The signal for controlling the pump flow rate can be, for example, a drive current for energizing the cooling pump 104 so that the cooling pump 104 has a desired flow rate.

  The controller 202 is a computer having a processor such as a CPU (Central Processing Unit), a ROM (Read Only Memory) in which a program is written, a RAM (Random Access Memory) for temporary storage of data, and the like, and a calorific value calculation unit 210, a target flow rate determination unit 212, a target decrease rate determination unit 214, and a pump flow rate control unit 216.

  Each unit included in the controller 202 is realized by the controller 202 being a computer executing a program, and the computer program can be stored in any computer-readable storage medium. Instead of this, or in addition to this, all or a part of each of the above units can be configured by hardware including one or more electronic circuit components.

  The heat generation amount calculation unit 210 repeatedly calculates the current heat generation amount of the internal combustion engine 102 based on the intake air amount acquired from the intake sensor 134 via the input INF 200 at predetermined time intervals, and calculates the calculated heat generation amount. And stored in the storage device 204 described later. In the present embodiment, the current heat generation amount is calculated based on the intake air amount. However, the present invention is not limited to this, and other parameters (for example, the rotational speed of the internal combustion engine 102, the throttle opening, and / or the fuel injection) are calculated. The calorific value can also be calculated based on the amount.

  The target flow rate determination unit 212 stores the current cooling water temperature acquired from the water temperature sensor 120 via the input INF 200 at a predetermined time interval in the storage device 204 described later. Further, the target flow rate determination unit 212 is based on the calorific value calculated by the calorific value calculation unit 210 at predetermined time intervals, and the absolute amount of change between the calorific value calculated last time (previous calorific value) and the current calorific value is calculated. If the value (heat generation change amount) ΔQc is equal to or greater than a predetermined first threshold value Qth1, it is determined that there is a significant change in the heat generation amount, and based on the current heat generation amount and the current cooling water temperature, The target flow rate of the cooling pump 104 is determined with reference to a target flow rate map 220 stored in the storage device 204 described later. The determined target flow rate is output to a pump flow rate control unit 216 described later.

  The target decrease rate determination unit 214 determines whether the current heat generation amount has decreased with respect to the heat generation amount calculated last time (previous heat generation amount) based on the heat generation amount calculated by the heat generation amount calculation unit 210 at predetermined time intervals. When the flow rate of the cooling pump 104 is reduced to the target flow rate, the average of the flow rates when the flow rate of the cooling pump 104 is reduced to the target flow rate is referred to with reference to a target reduction PM map 222 stored in the storage device 204 described later. The target value (target decrease parameter value) of the operation parameter that defines the decrease rate is output to the pump flow rate control unit 216.

  The pump flow rate control unit 216 uses the target flow rate output from the target flow rate determination unit 212 and the target decrease parameter value output from the target decrease rate determination unit 214 based on the average decrease rate defined by the target decrease parameter value. The flow rate of the cooling pump 104 is controlled so as to decrease to the target flow rate.

  In the present embodiment, as an example, the pump flow rate control unit 216 reduces the flow rate of the cooling pump 104 so as to decrease along a decrease curve according to an exponential function, and the target decrease parameter that defines the average decrease rate. The value is assumed to be a time constant of a decreasing curve according to the exponential function. However, the present invention is not limited to this, and the pump flow rate control unit 216 may decrease the flow rate of the cooling pump 104 linearly or nonlinearly in time along an arbitrary decrease curve. In this case, the target decrease parameter value that defines the average decrease rate is, for example, the value of the average decrease rate to be realized by the arbitrary decrease curve (for example, the flow rate decrease rate per unit time) or the flow rate decrease. The time from the start to the end. In the present specification, the “reduction rate” in the case of “target reduction rate” and “average reduction rate” may be the “flow rate reduction rate per unit time” as described above.

  The storage device 204 can be a storage device including a volatile and / or nonvolatile memory (for example, a semiconductor memory), a hard disk, and the like. The storage device 204 stores the previous heat generation amount and the current heat generation amount repeatedly calculated by the heat generation amount calculation unit 210, and the previous cooling water temperature and the current cooling water temperature repeatedly acquired by the target flow rate determination unit 212.

  The storage device 204 stores in advance a target flow rate map 220 that indicates the target flow rate of the cooling pump in accordance with the current heat generation amount of the internal combustion engine 102. Further, the storage device 204 also stores a target reduction parameter map (target reduction PM map) 222 that indicates a target reduction parameter value corresponding to the previous heat generation amount and the previous cooling water temperature. Here, as described above, the target reduction parameter value is an operation parameter that defines an average reduction rate of the flow rate when the heat generation amount of the internal combustion engine 102 is reduced and the flow rate of the cooling pump 104 is reduced to the target flow rate. In this embodiment, it is the value of the time constant of the flow rate decrease curve according to the exponential function used when the pump flow rate control unit 216 reduces the flow rate of the cooling pump 104.

FIG. 3 is a diagram illustrating an example of the target flow rate map 220 stored in advance in the storage device 204. In the illustrated example, the cooling pump according to the current heat generation amount (that is, the current heat generation amount) of the internal combustion engine 102 indicated on the vertical axis and the current cooling water temperature (that is, the current cooling water temperature) indicated on the horizontal axis. 104 target flow rates are shown in each zone in the two-dimensional plane defined by the vertical and horizontal axes. In other words, the target flow rate is V ₁₀ for the range of heat generation and cooling water temperature in the zone surrounded by the line 300 and the vertical and horizontal axes, and the heat generation in the zone sandwiched between the line 300 and the line 302 and the vertical axis. The target flow rate is V ₂₀ ,. . . The target flow rate is V ₈₀ for the range of the calorific value and cooling water temperature of the zone sandwiched between the lines 312 and 314, and the target flow rate for the range of the calorific value and cooling water temperature of the zone on the right side of the line 314 in the figure. Is shown to be V ₉₀ . The target flow rate determination unit 212 described above corresponds by referring to the target flow rate map 220 based on the current heat generation amount calculated by the heat generation amount calculation unit 210 and the current cooling water temperature acquired from the water temperature sensor 120. Determine the target flow rate.

  FIG. 4 is a diagram illustrating an example of the target reduction PM map 222 stored in advance in the storage device 204. In the illustrated example, the target reduction PM map 222 includes a target reduction PM map A shown in FIG. 4A and a target reduction PM map B shown in FIG. In the target reduction PM map A, the current heat generation amount decrease amount (heat generation decrease amount) ΔQd (assuming a positive value when the current heat generation amount has decreased with respect to the previous time) The target decrease PM map B is used when it is less than a predetermined second predetermined threshold value Qth2, and the target decrease PM map B is used when the heat generation decrease amount ΔQd is equal to or greater than the threshold value Qth2.

In the target reduction PM map A shown in FIG. 4A, a two-dimensional plane region defined by the heat generation amount on the vertical axis and the cooling water temperature on the horizontal axis (for example, the maximum rating Q3 of the heat generation amount and the cooling water (cooling) The operation range defined by the maximum use temperature T3 of the substance) is divided into nine zones each dividing the change range of the calorific value and the cooling water temperature into three zones, and the time constant corresponding to each zone is divided. Is indicated by t _max , t _mid , or t _min . Further, in the target reduction PM map B shown in FIG. 4B, the region of the two-dimensional plane is divided into three zones that divide the cooling water temperature change range into three, and each zone corresponds to the above-described zone. A time constant is specified.

Here, it is assumed that t _max > t _mid > t _min and t _min is greater than a predetermined lower limit value t _limit . In other words, the time constant t _min defines that the flow rate is decreased more slowly than a predetermined flow rate gradient (flow rate reduction rate) determined by the lower limit time constant t _limit , and the time constant t _mid is less than t _min. The time constant t _max specifies that the flow rate is decreased at the slowest flow rate gradient, and the time constant t _max is used to specify that the flow rate is decreased at the slowest flow rate gradient.

  FIG. 5 is a diagram for explaining a method of determining the value of the time constant that is the target decrease parameter value from the target decrease PM map 222 shown in FIG. More specifically, FIG. 5 is a diagram in which the target reduction PM map A shown in FIG. 4A is superimposed on the flow rate map similar to FIG. 3, and each arrow shown in FIG. It shows that the operation of the internal combustion engine 102 has changed from the operating point (illustrated white circle) indicated by the amount of generated heat and the previous cooling water temperature to the operating point indicated by the current amount of heat generated and the current cooling water temperature (illustrated black circle). That is, the vertical axis in FIG. 5 represents the previous or current calorific value, and the horizontal axis represents the previous or current cooling water temperature.

In the operating point change indicated by reference numeral 500, the operating point before the change is in the zone 1 and the time constant t _max is defined for the zone 1, and the operating point after the change is in the zone 4 and the zone 4 defines a time constant t _min . As shown on the vertical axis of FIG. 4A, the target decrease parameter value (in this embodiment, the time constant) is determined according to the previous heat generation amount. The time constant t _max defined in the zone 1 where the previous operating point exists is determined as the target decrease parameter value. Similarly, in the operating point changes indicated by reference numerals 502, 504, 506, and 508, since the operating points before the change are in Zone 1, Zone 4, Zone 7, and Zone 5, respectively, the time constants t _max , t _min , t _min and _tmid are determined as target reduction parameter values.

In this way, the target decrease parameter value is determined according to the previous heat generation amount because the amount of heat Q _eq that should be radiated by the cooling water circulation until the cooling water temperature reaches the water temperature corresponding to the current heat generation amount and stabilizes. This is because (that is, a part of the amount of heat accumulated in the main body structure of the internal combustion engine 102) depends on the amount of heat generated last time (that is, the amount of heat generated before the operating point is changed).

Since the heat quantity Q _eq is larger as the heat generation amount before the operating point change (that is, the previous heat generation amount) is larger, the target decrease PM map A shown in FIG. The large time constant is determined. In addition, since the heat dissipation efficiency due to the cooling water circulation is lower as the cooling water temperature is higher, in the target reduction PM map A shown in FIG. 4A, the higher the cooling water temperature is, the more cooling water is circulated for a longer time. A large time constant is specified.

  On the other hand, in the target decrease PM map B shown in FIG. 4 (b) used when the heat generation decrease amount ΔQd (the current heat generation amount decrease amount with respect to the previous heat generation amount) is larger than the predetermined threshold value Qth2, it depends only on the cooling water temperature. The time constant is defined by the fact that ΔQd is greater than Qth2, which means that the operating point before the change was in a state of heat generation greater than a certain value Qth2, so that the cooling water regardless of the heat generation amount. This is because it is sufficient to determine the time constant depending only on the temperature.

In the target reduction PM map B shown in FIG. 4B, the same time constant is defined for each of the three zones. However, the present invention is not limited to this, and other time constants are set in one of these three zones. It may be defined, or each zone may define a different time constant. In this embodiment, by defining as shown in FIG. 4B, when the heat generation reduction amount ΔQd is larger than the predetermined threshold value Qth2, always using one time constant (t _max ) regardless of the cooling water temperature, It is assumed that the flow rate of the cooling pump 104 is decreased at a predetermined average decrease rate.

4 (a) and 4 (b), the two-dimensional plane defined by the calorific value on the vertical axis and the cooling water temperature on the horizontal axis is divided into nine and three, respectively, and the target reduction parameter value is obtained. Although prescribed | regulated, it is not restricted to this, The number of the zones which divide the said two-dimensional plane can be made into arbitrary numbers. In addition, the number of time constant values that are target decrease parameter values is not limited to three of t _max , t _mid , or t _min , and can be an arbitrary number.

Further, in FIGS. 4A and 4B, the target reduction parameter value is defined for each zone that divides the two-dimensional plane defined by the calorific value on the vertical axis and the cooling water temperature on the horizontal axis. However, the present invention is not limited to this. For example, when the cooling efficiency by the cooling water circulation does not depend much on the cooling water temperature, the target decrease parameter value can be determined only according to the previous heat generation amount. Thus, even when the target decrease parameter value is determined only in accordance with the previous heat generation amount, the flow rate of the cooling water is slowly decreased at an average decrease rate in accordance with the previous heat generation amount. The amount of heat Q _eq of the internal combustion engine 102 that should be dissipated by circulating the cooling water before the water temperature corresponding to the current heat generation amount is stabilized and stabilized, can be effectively dissipated as in the case of the present embodiment.

  FIG. 6 is an explanatory diagram for explaining the operation of the pump control apparatus 100 over time. 6A shows the change over time in the amount of heat generation, FIG. 6B shows the change over time in the cooling water temperature, and FIG. 6C shows the change over time in the pump flow rate. The horizontal axis is time.

  At time t10, for example, when the driver depresses the accelerator and the intake valve 132 is opened, the amount of heat generated by the internal combustion engine 102 increases from time t10 to time t20 after a predetermined time interval Δt (FIG. 6 (a)). )), The pump control apparatus 100 detects the increase in the heat generation amount from the change in the intake air amount acquired from the intake air sensor 134 at times t10 and t20.

  Then, the target flow rate determination unit 212 determines the target flow rate with reference to the target flow rate map 220 based on the current cooling water temperature acquired from the water temperature sensor 120 and the current heat generation amount calculated by the heat generation amount calculation unit 210. To do. As a result, the pump flow rate control unit 216 increases the energization current to the cooling pump 104 immediately after time t20, and increases the flow rate of the cooling pump 104 so that the determined target flow rate is obtained.

  At this time, the change in the heat generation amount of the internal combustion engine 102 from time t10 to t20 is an increase rather than a decrease, so the pump flow rate control unit 216 simply changes the flow rate of the cooling pump 104 to the target flow rate in a stepped manner. As a result, the pump flow rate increases all at once from time t20 to time t30 (FIG. 6C). On the other hand, the cooling water temperature continues to increase slowly due to the heat capacity of the main body metal of the internal combustion engine 102 (FIG. 6B).

  Thereafter, at time t40, for example, the driver depresses the accelerator and the opening of the intake valve 132 is closed, and the amount of heat generated by the internal combustion engine 102 decreases from time t40 to time t50 after a predetermined time interval Δt. Then (FIG. 6A), the target decrease rate determination unit 214 and the pump flow rate control unit 216 detect the decrease in the heat generation amount from the heat generation amount calculated by the heat generation amount calculation unit 210 at times t40 and t50.

  Then, the target flow rate determination unit 212 refers to the target flow rate map 220 based on the current cooling water temperature obtained at the time t50 acquired from the water temperature sensor 120 and the current heat generation amount at the time t50 calculated by the heat generation amount calculation unit 210. To determine the target flow rate. On the other hand, the target decrease rate determination unit 214 calculates the target decrease PM map based on the previous heat generation amount calculated at time t40 by the heat generation amount calculation unit 210 and the previous cooling water temperature acquired from the water temperature sensor 120 at time t40. Referring to 222 (that is, target reduction PM map A or target reduction PM map B shown in FIG. 4), a time constant that is a target reduction parameter value is determined.

  Subsequently, the pump flow rate control unit 216 uses the time constant determined by the target decrease rate determination unit 214 to adjust the flow rate of the cooling pump 104 according to an exponential function so as to be the target flow rate determined by the target flow rate determination unit 212. Decrease along the decreasing curve (FIG. 6C). As a result, the flow rate of the cooling pump 104 does not change stepwise (as indicated by the dotted line in FIG. 6C) as in the prior art, but slowly decreases immediately after time t50, and reaches the target at time t60. The flow rate will be reached.

  The cooling pump control device 100 having the above configuration repeatedly specifies the heat generation amount and the cooling water temperature of the internal combustion engine 102 at predetermined time intervals, and determines the target flow rate of the cooling pump 104 by the target flow rate determination unit 212. Then, when the heat generation amount repeatedly specified decreases, the flow rate of the cooling pump 104 is slowly decreased to the target flow rate at an average decrease rate corresponding to the heat generation amount before the decrease change.

  As a result, the pump control apparatus 100 can effectively dissipate the heat accumulated in the main body structure of the internal combustion engine 102 before the heat generation amount is reduced until the flow rate of the cooling pump 104 reaches the target flow rate. The temperature of the internal combustion engine 102 can be controlled within an appropriate range.

  Next, the operation procedure of the pump control apparatus 100 will be described with reference to the flowchart shown in FIG. The process shown in FIG. 7 starts when the power supply of the pump control device 100 is turned on, and is repeatedly executed at predetermined time intervals.

  When the process is started, first, the calorific value calculation unit 210 and the target flow rate determination unit 212 receive the sensor signals from the intake sensor 134 and the water temperature sensor 120 via the input INF 200, respectively, and the intake air amount acquired from the intake sensor 134, respectively. For example, the current heat generation amount of the internal combustion engine 102 calculated based on the following (hereinafter referred to as the current heat generation amount) and the current cooling water temperature acquired from the water temperature sensor 120 (hereinafter referred to as the current cooling water temperature) are stored, for example. It memorize | stores in the apparatus 204 (S100).

  Next, the calorific value calculation unit 210 performs the following operation on the calorific value stored in the storage device 204 in step S100 during the previous execution of this process repeatedly executed at predetermined time intervals (hereinafter referred to as the previous calorific value). It is determined whether or not the absolute value (heat generation change amount) ΔQc of the change amount of the current heat generation amount is equal to or greater than a predetermined first threshold value Qth1 (S102). S102, No), assuming that the calorific value has not changed significantly, this processing is terminated.

  On the other hand, when the heat generation change amount ΔQc is equal to or greater than the first threshold value Qth1 (S102, Yes), the target flow rate determination unit 212 acquires the current heat generation amount calculated by the heat generation amount calculation unit 210 and the water temperature sensor 120. Based on the current coolant temperature, the target flow rate 220 stored in the storage device 204 is referred to determine the target flow rate, and the determined target flow rate is output to the pump flow rate control unit 216 (S104).

  Next, the target decrease rate determination unit 214 and the pump flow rate control unit 216 each determine whether or not the current heat generation amount has decreased with respect to the previous heat generation amount (S106). If not decreasing (S106, No), the pump flow rate control unit 216 starts the flow rate control of the cooling pump 104 so that the flow rate of the cooling pump 104 becomes the determined target flow rate (S108). ), This process is terminated. Note that after the flow rate control is started in step S108, the pump flow rate control unit 216 determines that the target flow rate that has already been determined is determined unless a new target flow rate is determined in step S104 of this process that is repeatedly executed at predetermined time intervals. The started flow control is continued so as to be maintained.

  On the other hand, when the current heat generation amount is decreasing with respect to the previous heat generation amount (S106, Yes), the target reduction rate determination unit 214 decreases the current heat generation amount with respect to the previous heat generation amount (heat generation decrease amount). It is determined whether or not ΔQd is less than a predetermined second threshold value Qth2 (S110), and if it is less than Qth2 (S110, Yes), the target decrease rate determination unit 214 stores the storage device 204. Referring to the target reduction PM map A stored in FIG. 4, the previous heat generation amount and the coolant temperature stored in the storage device 204 in step S100 at the previous execution of this process repeatedly executed at a predetermined time interval. (Hereinafter referred to as the previous cooling water temperature), the flow rate reduction according to the exponential function as the target value (target reduction parameter value) of the operating parameter that defines the average flow rate reduction rate Determining a value of the time constant of the curve (S112).

  On the other hand, when the heat generation reduction amount ΔQd is equal to or greater than Qth2 (S110, No), the target reduction speed determination unit 214 refers to the target reduction PM map B stored in the storage device 204 and sets the previous cooling water temperature. Based on this, the value of the time constant that is the target decrease parameter value is determined (S114).

  Subsequently, the pump flow rate control unit 216 decreases based on the exponential function defined by the time constant based on the target flow rate determined in step S104 and the time constant which is the target decrease parameter value determined in step S112 or S114. After starting the flow control of the cooling pump 104 so that the flow rate decreases to the target flow rate along the curve (S116), the process is terminated.

  Note that after the flow rate control is started in step S116, the pump flow rate control unit 216 has already set the flow rate of the cooling pump 104 unless a new target flow rate is determined in step S104 of this process that is repeatedly executed at predetermined time intervals. The above-described flow control is continued until the determined target flow rate is reached, and after reaching the target flow rate, the flow rate control is performed so that the target flow rate is maintained.

  As described above, the pump control apparatus 100 according to the present embodiment reduces the heat generation amount instead of reducing the pump flow rate of the cooling pump 104 to the target flow rate all at once when the heat generation amount of the internal combustion engine 102 decreases. Since it is decreased at an average decrease rate according to the previous heat generation amount, the heat accumulated in the main body structure of the internal combustion engine 102 until the target flow rate is reached is effectively dissipated, and the internal combustion engine The temperature of 102 can be controlled within an appropriate range.

  DESCRIPTION OF SYMBOLS 100 ... Cooling pump control apparatus, 102 ... Internal combustion engine, 104 ... Cooling pump, 114 ... Radiator, 120 ... Water temperature sensor, 124 ... Thermostat, 130 ... Intake pipe, 132 ... Intake valve, 134 ... Intake sensor, 200 ... Input interface, 202 ... Controller, 204 ... Storage device, 206 ... Output interface, 210 ... Heat generation calculation unit, 212 ... target flow rate determination unit, 214 ... target reduction speed determination unit, 216 ... pump flow rate control unit, 220 ... target flow rate map, 222 ... target reduction parameter (PM) map.

Claims (7)

A cooling pump control device for controlling a flow rate of a cooling pump for circulating cooling water to an internal combustion engine,
A controller for determining a target flow rate according to the current calorific value of the internal combustion engine and controlling the flow rate of the cooling pump so as to be the target flow rate;
When the controller decreases the flow rate of the cooling pump in accordance with a decrease in the heat generation amount of the internal combustion engine, the controller decreases the flow rate at a smaller average decrease rate as the heat generation amount before the change in the heat generation amount increases. Configured,
Cooling pump control device. When the controller decreases the flow rate of the cooling pump in accordance with a decrease in the heat generation amount of the internal combustion engine, the controller further decreases the flow rate by a smaller average as the temperature of the cooling water before the change in the heat generation amount increases. Configured to decrease at speed,
The cooling pump control device according to claim 1. The controller determines the flow rate in advance when the amount of change in the heat generation amount exceeds a predetermined amount when the flow rate of the cooling pump is decreased in accordance with a decrease in the heat generation amount of the internal combustion engine. Decrease at a predetermined average decrease rate,
The cooling pump control device according to claim 1 or 2. The controller is
Configured to decrease the flow rate along a decreasing curve expressed in an exponential function, and
The larger the heat generation amount before the change in the heat generation amount of the internal combustion engine is, the larger the time constant of the decrease curve is, and the flow rate is decreased at a small average decrease rate.
The cooling pump control device according to claim 1. The controller is
Configured to decrease the flow rate along a decreasing curve expressed in an exponential function, and
The higher the temperature of the cooling water before the change in the calorific value of the internal combustion engine is, the larger the time constant of the decrease curve is, and the flow rate is decreased at a small average decrease rate.
The cooling pump control device according to claim 4. The controller is
When the flow rate of the cooling pump is decreased with a decrease in the heat generation amount of the internal combustion engine, if the amount of change in the heat generation amount exceeds a predetermined amount, the time constant is set to a predetermined value. To reduce the flow rate at a predetermined average reduction rate,
The cooling pump control device according to claim 5. The amount of heat generated by the internal combustion engine is determined from the amount of intake air of the internal combustion engine.
The cooling pump control device according to any one of claims 1 to 5.

Images