WO2017056944A1

WO2017056944A1 - Cooling control device

Info

Publication number: WO2017056944A1
Application number: PCT/JP2016/076811
Authority: WO
Inventors: 渡邉寛隆; 豊田泰延; 吉田昌弘; 島谷和良
Original assignee: アイシン精機株式会社
Priority date: 2015-09-30
Filing date: 2016-09-12
Publication date: 2017-04-06
Also published as: US20180252147A1; JP2017067018A; EP3358163B1; EP3358163A1; JP6488970B2; EP3358163A4; CN107923303A

Abstract

A cooling control device is equipped with: a first heat exchanger to which a coolant for an internal combustion engine is supplied; a radiator to which the coolant is supplied; a coolant pump that supplies the coolant; a flow volume control valve that controls the flow volume of the coolant; and a control unit that controls the flow volume control valve. The control unit obtains a first heat quantity stored in the coolant, a second heat quantity stored in the coolant by means of a heat exchange with the first heat exchanger, and a third heat quantity for changing the coolant to a target temperature. The control unit sets a target heat radiation amount from these heat quantities, and sets the degree of opening of the flow volume control valve by feed-forward control.

Description

Cooling control device

The present invention relates to a cooling control device that performs temperature management of an internal combustion engine using a coolant.

As a cooling control device having the above-described configuration, Patent Document 1 sets the target temperature of cooling water based on the operating state of the internal combustion engine, and in order to achieve the target heat dissipation efficiency, the amount of cooling by the electric cooling device is determined from the heat dissipation model. A technique for acquiring and controlling an electric cooling device based on the acquired cooling amount is shown.

This Patent Document 1 also shows a processing mode in which target heat dissipation efficiency is set by feedback control based on a deviation between a target temperature and an actual temperature and feedforward control based on an engine heat quantity. As an electric cooling device, a radiator fan, a water pump, and a thermostat are shown, and these are controlled in order to realize cooling of the cooling amount.

In Patent Document 2, the total heat quantity of the cooling system is calculated from the cooling system heat quantity stored in the cooling system of the internal combustion engine (drive source) according to the coolant temperature and the vehicle power source heat radiation quantity radiated by the internal combustion engine in the operating state. A control mode for estimating and determining the target total heat amount of the radiator and the flow rate of the radiator based on this is shown.

In this patent document 2, an electric water pump for setting the amount of cooling water is provided, a thermo valve is provided at a joint portion between the cooling water outlet of the internal combustion engine and a radiator lower hose, and a bypass passage is provided between the thermo valve and the electric water pump. And the mixing ratio of the cooling water from the outlet of the internal combustion engine and the cooling water from the radiator hose is adjusted by the opening of the thermo valve.

JP 2014-218938 A JP 2005-248903 A

Considering the control that suppresses the temperature increase of the internal combustion engine by supplying the coolant to the radiator, even if heat is radiated by the radiator, this radiant heat does not immediately appear as a temperature drop of the coolant. Therefore, for example, feedback control that detects the coolant temperature with a temperature sensor and adjusts the coolant flow rate may cause excessive heat dissipation or delay the timing of heat dissipation, leading to hunting, It becomes difficult to keep the temperature of the coolant constant.

For these reasons, the techniques of Patent Document 1 and Patent Document 2 described above are configured so that the temperature of the cooling water can be managed by feedforward control.

Here, in the case of a vehicle equipped with an EGR cooler, part of the heat discharged together with the exhaust gas is removed by the coolant in the EGR cooler. Further, in a vehicle equipped with an oil cooler, the heat of the lubricating oil is removed by the cooling liquid in the oil cooler, or conversely, the lubricating oil is heated by the heat of the cooling liquid. In particular, since high-temperature exhaust gas is supplied to the EGR cooler, the amount of heat transferred from the EGR cooler to the coolant cannot be ignored.

In addition, if a cooling circuit in which these coolants are circulated uses a mechanical water pump driven by an engine, the configuration is simple and inexpensive. However, the temperature control is difficult because the amount of cooling water varies as the engine speed varies.

That is, there is a need for a cooling control device that has a mechanical pump and performs temperature management of an internal combustion engine having a heat exchanger such as an EGR cooler with high accuracy.

The present invention is characterized in that a radiator to which a coolant of an internal combustion engine is supplied, a first heat exchanger that performs heat exchange with the coolant separately from the radiator, and the internal combustion engine for circulating the coolant. A driven coolant pump, a flow rate control valve for setting the flow rate of the coolant, and a control unit for setting the opening of the flow rate control valve;
A first heat amount that the internal combustion engine gives to the coolant according to a rotational speed of the internal combustion engine and a load acting on the internal combustion engine; and a second heat amount that the first heat exchanger gives to the coolant. And a third heat quantity that is transferred to change the coolant to the target temperature, and a heat quantity acquisition unit that acquires the third heat quantity, and the first heat quantity, the second heat quantity, and a unit time obtained by the heat quantity acquisition part. A target heat dissipation amount setting unit for setting a target heat dissipation amount based on a value obtained by adding the third heat amount,
The control unit sets a target flow rate of the coolant to be supplied to the radiator based on the target heat dissipation amount set by the target heat dissipation amount setting unit and the heat exchange efficiency in the radiator, and feedforward control is used to set the target flow rate. It is in the point provided with the opening setting part which sets the target opening of a flow control valve.

For example, when the accelerator pedal is depressed, the amount of fuel consumed in the internal combustion engine increases as the rotational speed of the internal combustion engine and the load acting on the internal combustion engine increase, and the first amount of heat generated in the internal combustion engine Will also increase. When the load of the internal combustion engine increases, the first heat exchanger gives the second amount of heat to the coolant. Further, the first heat amount, the second heat amount, and the third heat amount transferred to change the coolant to the target temperature are acquired by the heat amount acquisition unit. After this acquisition, the target heat release amount setting unit sets the target heat release amount based on a value obtained by adding the first heat amount, the second heat amount, and the third heat amount per unit time. Further, the opening degree setting unit sets a target flow rate to be supplied to the radiator based on the target heat dissipation amount and the heat exchange efficiency of the radiator, and performs feedforward control in which the opening degree of the flow control valve is set to the target opening degree. Is called.

In other words, in this control, even when the coolant temperature does not increase immediately, such as immediately after the accelerator pedal is depressed, and the coolant temperature rises thereafter, the radiator is set before the coolant temperature rises. The supply amount of the coolant to be supplied can be increased. Therefore, the heat radiation timing is not delayed by feedforward control reflecting the amount of heat acting on the coolant from the first heat exchanger, and an appropriate heat radiation amount can be set. In addition, since the flow rate of the coolant is set by the opening degree of the flow control valve, it is possible to set an appropriate heat radiation amount while using a coolant pump driven by the internal combustion engine.
Therefore, a cooling control device is constructed that performs a temperature control of an internal combustion engine having a mechanical pump and a heat exchanger such as an EGR cooler with high accuracy.

In the present invention, the amount of heat acquired by the heat amount acquisition unit is provided separately from the fourth amount of heat exchanged between the coolant and the block portion of the internal combustion engine, and the radiator and the first heat exchanger. The second heat exchanger may include a temperature difference between the coolant flowing inside and the heat exchange target and a fifth heat quantity obtained from the flow rate.

The fourth heat amount and the fifth heat amount are not as large as the first heat amount and the second heat amount, but affect the liquid temperature of the coolant. Therefore, accurate and highly accurate temperature management is realized by reflecting the fourth heat amount and the fifth heat amount in the target flow rate of the coolant.

In the present invention, the second heat exchanger may be an oil cooler.

This makes it possible to exchange heat between the coolant flowing inside the oil cooler and the lubricating oil.

In the present invention, when the deviation between the target heat dissipation amount and the amount of heat acquired by the heat amount acquisition unit falls below a predetermined threshold, the deviation is reduced by feedback control while performing feedforward control. May be executed.

実行 By executing the feedforward control, the target heat quantity is radiated from the coolant, and the liquid temperature deviation of the coolant can be reduced. However, since the control is based on the amount of heat, the control is difficult to converge, and the accuracy of the temperature control is improved by switching to the feedback control that further reduces the deviation of the coolant temperature while performing the feedforward control. To do.

In the present invention, a target response time for managing the temperature of the internal combustion engine may be set, and the opening setting unit may set a target opening of the flow control valve based on the target response time.

For example, in a situation where the temperature of the internal combustion engine rises for a short time, such as when the accelerator pedal is depressed suddenly, it is appropriate to perform control based on the temperature of the internal combustion engine due to insufficient heat conduction of the internal combustion engine. Temperature control is difficult, and it is necessary to set a target response time for radiating a necessary amount of heat by the timing when boiling of the coolant is assumed. Further, when the temperature increase of the internal combustion engine is suppressed even in a situation where excessive cooling shortage is caused when the accelerator pedal depression operation is released, heat is released by taking a sufficient time until the expected timing is exceeded. Target response time is required.
In this configuration, when the target response time is set, the temperature management of the internal combustion engine can be appropriately performed by setting the opening degree of the flow control valve based on the target response time.

It is a figure which shows the structure of a cooling control apparatus. It is a chart which shows the opening degree of each valve part with respect to the operation amount of a valve body. It is a block circuit diagram of a cooling control device. It is a flowchart of cooling control. It is a block diagram which shows the relationship of the calorie | heat amount of a cooling water. It is a chart which shows the relationship between the valve opening degree at the time of control, and water temperature. It is a figure which shows the relationship between the air volume and heat dissipation in a radiator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIG. 1, a water pump WP (an example of a cooling liquid pump) that sends cooling water (an example of a cooling liquid) of an engine E as an internal combustion engine, and a plurality of flow paths F (first flow) formed in parallel. The flow rate for controlling the flow of the cooling water (an example of the cooling liquid), the heat exchanger provided in each of the plurality of flow paths F, and the superordinate concept of the path F1, the second flow path F2, and the third flow path F3). A cooling circuit including the control valve V and a control unit 10 (an example of a control unit) are included to constitute a cooling control device.

This cooling control device detects the water temperature of the cooling water (cooling liquid) with a water temperature sensor S (an example of a liquid temperature sensor), and the control unit 10 controls the flow rate control valve V based on the detection result, which will be described later. The heat exchange between the first supply mode M1 and the second supply mode M2 is managed.

As a heat exchanger whose cooling water is controlled by the flow rate control valve V, an EGR cooler 1 (specific example of the first heat exchanger), an oil cooler 2 (specific example of the second heat exchanger), and a radiator 3 are provided. I have. Further, the water pump WP (coolant pump) is driven by the crankshaft of the engine E and is disposed between the flow control valve V and the engine E.

The cooling control device is configured to perform temperature management of an engine E (internal combustion engine) of a vehicle such as a passenger car. The engine E is assumed to have a water jacket formed in an area extending from the cylinder block to the cylinder head, for example, like a reciprocating engine. The cooling control device is configured to send the cooling water in the water jacket to the flow path F, supply the cooling water to the heat exchanger to exchange heat, and then return the water jacket to the water jacket by the water pump WP. The engine E is configured to transmit a driving force from a crankshaft as an output shaft to the transmission. The engine E is not limited to a reciprocating engine. Further, the engine E is not limited to the configuration in which the driving force is directly applied to the transmission, but may be one that transmits the driving force to the electric motor, for example, like a hybrid vehicle.

[Flow path / Heat exchanger]
The water temperature sensor S is provided in the engine E, and a plurality of flow paths F are formed in a form branched from a main flow path FM through which cooling water is sent from the engine E. In the present embodiment, a first channel F1, a second channel F2, and a third channel F3 are formed as the plurality of channels F. As a heat exchanger, the EGR cooler 1 is provided in the first flow path F1, the oil cooler 2 is provided in the second flow path F2, and the radiator 3 is provided in the third flow path F3.

The technology that improves the components in the exhaust gas and improves the fuel efficiency by taking out part of the exhaust gas of the engine E and returning it to the intake system is called EGR (Exhaust Gas Recirculation). The EGR cooler 1 Part of the exhaust gas taken out from the chamber is heat exchanged (cooled) with cooling water.

The oil cooler 2 has a configuration in which the lubricating oil stored in the oil pan 5 of the engine E is supplied by the oil pump 6, and performs heat exchange with the cooling water. The lubricating oil that has been subjected to heat exchange in the oil cooler 2 is supplied to hydraulic operating devices such as a valve opening / closing timing control device or lubricating portions of various parts of the engine. The oil pump 6 is a variable hydraulic mechanical oil pump that can control the hydraulic pressure level in two or more stages, and is driven by the engine E.

The radiator 3 has a function of managing the temperature of the engine E by radiating the cooling water, and the cooling air is supplied from the radiator fan 7. The radiator fan 7 is driven by a fan motor 7M configured by an electric motor.

(Flow control valve)
The flow control valve V is a rotary type in which a valve body is rotatably accommodated in a valve case, and a valve motor VM that is an electric motor so as to rotate the valve body, and a valve that detects a rotation angle of the valve body. And a sensor VS. The valve sensor VS is composed of a hall element, a potentiometer, and the like, and by detecting the rotation angle of the valve body of the flow control valve V, it is possible to detect the opening of the valve portion in each supply mode in the flow control valve V. To do. The flow control valve V may adopt a slide operation type in which a valve body that slides is accommodated inside the valve case.

The flow control valve V includes a first valve portion V1 that opens and closes the first flow path F1, a second valve portion V2 that opens and closes the second flow path F2, and a third valve portion V3 that opens and closes the third flow path F3. have. FIG. 2 shows the opening degrees of the first valve portion V1, the second valve portion V2, and the third valve portion V3 with respect to the operation amount of the valve body in the flow rate control valve V having this configuration. The first valve portion V1, the second valve portion V2, and the third valve portion V3 are collectively referred to as valve portions.

In FIG. 2, the vertical axis indicates the opening degree of the first valve part V1, the second valve part V2, and the third valve part V3 (the opening degree is expressed as a percentage), and the horizontal axis indicates the valve operating amount. (Rotation amount) is shown. As can be understood from the figure, when the valve body is in the initial position, the first valve portion V1, the second valve portion V2, and the third valve portion V3 are in the fully closed mode M0 in which they are closed, Cooling water does not flow through the first flow path F1, the second flow path F2, and the third flow path F3.

Next, the opening degree of the first valve portion V1 is adjusted while the second valve portion V2 and the third valve portion V3 are maintained in the closed state by operating the valve body in the opening direction from the fully closed mode M0. Shifts to the first supply mode M1 in which

Further, by operating the valve body in the opening direction beyond the fully opened state of the first supply mode M1 from the first supply mode M1, the opening degree of the first valve unit V1 is maintained in the fully opened state (third valve The part V3 is maintained in the closed state), and the process proceeds to the second supply mode M2 in which the opening degree of the second valve part V2 can be adjusted.

Then, by operating the valve body from the second supply mode M2 in the opening direction beyond the fully opened state of the second supply mode M2, the opening degree of the first valve part V1 and the opening degree of the second valve part V2 part In a state where the valve is fully opened, the process proceeds to the third supply mode M3 in which the opening degree of the third valve portion V3 can be adjusted.

In particular, in this flow control valve V, the cooling water is not supplied by the second valve portion V2 before the opening degree of the first valve portion V1 reaches full open. Similarly, the cooling water is not supplied by the third valve portion V3 before the opening degree of the second valve portion V2 reaches the fully open position.

[Control unit / control type]
The control unit 10 manages the entire engine, and also manages the amount of heat exchanged by the heat exchanger by controlling the amount of cooling water flowing through the flow path F with the flow rate control valve V when the engine E is in operation. In particular, when temperature management of the engine E is performed, the flow rate of the cooling water supplied to the radiator 3 can be set optimally by the control of the flow rate control valve V.

As shown in FIG. 3, the control unit 10 includes a throttle sensor 21, an engine speed sensor 22, an outside air temperature sensor 23, an oil temperature sensor 24, a water temperature sensor S (an example of a liquid temperature sensor), and a valve sensor. A detection signal from VS is input. The control unit 10 also outputs control signals to the valve motor VM that controls the opening degree of the flow control valve V and the fan motor 7M that drives the radiator fan 7.

The throttle sensor 21 includes a potentiometer that detects the throttle position (opening) of the engine E. The engine speed sensor 22 is a non-contact type sensor that measures the speed of the crankshaft of the engine E. The outside air temperature sensor 23 is composed of a thermistor or the like that detects the outside air temperature of the vehicle. The oil temperature sensor 24 includes a thermistor that detects the oil temperature of the lubricating oil supplied to the oil cooler 2. The water temperature sensor S is provided in the engine E and is composed of a thermistor or the like.

The control unit 10 includes a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), etc., and a warm-up control unit 11 configured as software, a heat quantity acquisition unit 12, A target heat release amount setting unit 13, an opening degree setting unit 14, an opening degree correction unit 15, an air volume estimation unit 16, and a target water temperature setting unit 17 are provided. The control form by these is demonstrated based on the flowchart of FIG. 4, the block diagram of FIG. 5, and the chart of FIG.

FIG. 5 is a block diagram showing the relationship between the amount of heat stored in the cooling water and the amount of heat to be radiated by the radiator 3. The first heat quantity Q1 is a heat quantity given to the cooling water from the engine E to the cooling water during operation of the engine E (hereinafter referred to as engine heat quantity), and is proportional to the rotational speed of the engine E and the load acting on the engine E. Have a relationship. The second heat quantity Q2 is a heat quantity given to the cooling water per unit time from the EGR cooler 1 during operation of the engine E (hereinafter referred to as EGR heat quantity), and is applied to the rotational speed of the engine E and the load acting on the engine E. On the other hand, it is determined by a predetermined EGR rate. Here, the intake air amount can be acquired based on the throttle position (opening degree) of the throttle sensor 21. The second heat quantity Q2 increases as the EGR rate increases, and decreases as the EGR rate decreases.

The third heat quantity Q3 is the total heat quantity of the cooling water that is transferred to change the current water temperature of the cooling water to the target water temperature (hereinafter referred to as the cooling water heat quantity), and basically the actual water temperature and the target water temperature. The difference value is a value calculated by multiplying the total amount of cooling water and specific heat.

The fourth heat quantity Q4 is a heat quantity (hereinafter referred to as engine block heat quantity) that acts on the cooling water in the engine E through the engine block part constituting the outer wall part including the cylinder block from the cylinder head in the engine E. It is obtained based on the engine wall temperature and the actual water temperature. This engine block heat amount takes heat from the cooling water when the engine E is at a low temperature, and gives heat to the cooling water when the temperature of the engine E rises above a predetermined temperature. Since it is difficult to grasp the relationship between the engine wall temperature and the actual water temperature, the amount of heat must be set by calculation based on data obtained in advance from the relationship between the operating time of the engine E or the actual water temperature, or table data. become. Even when the engine E is not a reciprocating engine, the portion where the heat quantity of the cooling water acts is the engine outer wall portion.

The fifth heat quantity Q5 is a heat quantity (hereinafter referred to as oil heat quantity) given to the oil cooler 2 and the cooling water during operation of the engine E after warm-up (hereinafter referred to as oil heat quantity). Is an example of a heat exchange object), the amount of lubricating oil flowing through the oil cooler 2, the actual water temperature, and the cooling water amount.

A value obtained by dividing the third heat amount Q3 by the target response time T is defined as a third heat amount Q3 ′ per unit time, and the first heat amount Q1, the second heat amount Q2, the third heat amount Q3 ′ per unit time, the fourth heat amount Q4, By obtaining the sum (added value) of the fifth heat quantity Q5, the heat quantity to be radiated is obtained. In order to dissipate the obtained amount of heat, the target flow rate of cooling water to be supplied to the radiator 3 is set by considering the outside air temperature, the target response time T (see FIG. 6), etc. in the radiator model. Correspondingly, the target opening degree of the flow control valve V is set.

The target response time T is set to two types, one for promptly radiating heat (rapid heat dissipation) and one for allowing sufficient time to radiate heat (suppressed heat dissipation). That is, the target response time T for quick heat dissipation is a value indicating the time that must not be exceeded before completing the heat dissipation of the amount of heat to be dissipated when the flow rate control valve V is used to increase the flow rate of the cooling water. In addition, the target response time T for suppressing heat dissipation is a value indicating a time that must not be decreased until the heat dissipation of the heat amount to be radiated is completed in the control for reducing the flow rate of the cooling water by the flow rate control valve V. The target response time T is set based on the accelerator operation, the engine speed, the opening degree of the flow control valve V, and the like.

The reason why the target response time T is set is as follows. For example, in a situation where the temperature of the engine E rises for a short time, such as when the accelerator pedal is depressed suddenly, it is appropriate to perform control based on the temperature of the engine E due to insufficient heat conduction of the engine E. Temperature control is difficult. Therefore, it is necessary to radiate a heat amount necessary for suppressing boiling by assuming the timing of boiling of the coolant. For this reason, a target response time T for quick heat dissipation is set. Similarly, the target response time T for suppressing the temperature rise of the engine E is set even in a situation where excessive cooling shortage is caused when the accelerator pedal depression operation is released.

Thus, for example, when the flow rate of the cooling water is increased, the target opening degree of the flow control valve V is set to be larger as the target response time T for quick heat dissipation is shorter.

In the cooling control device, the opening degree setting unit 14 sets the rotation speed of the engine E (the rotation per unit time) during the control in any of the first supply mode M1, the second supply mode M2, and the third supply mode M3. Number) and the target response time T (see FIG. 6), the opening degree of the flow control valve V is set. That is, since the water pump WP is driven by the engine E, the rotational speed of the engine E is taken into consideration. Note that the target response time T shown in FIG. 6 is used as a switching timing from the feedforward control FF to the control that executes the feedforward control FF and the feedback control FB in parallel.

As a specific control mode, as shown in the flowchart of FIG. 4, cooling control is executed as the engine E is started, and the water temperature (actual water temperature) detected by the water temperature sensor S is lower than a specified value. When the machine operation is necessary, the warm-up operation is performed by maintaining the flow control valve V in the fully closed mode M0 (steps # 01 to # 03).

This warm-up operation is realized by the control of the warm-up control unit 11. In this warm-up operation, the first valve portion V1 is opened after the actual water temperature rises to a value suitable for heat exchange in the EGR cooler 1. In the first supply mode M1, the flow rate of the cooling water supplied to the first flow path F1 is increased by increasing the opening of the first valve portion V1 as the actual water temperature rises.

Following this, after the actual water temperature further rises and the opening degree of the first valve portion V1 exceeds 100% (after the actual water temperature reaches a predetermined value or more), the second valve portion V2 is opened. The In the second supply mode M2, the flow rate of the cooling water supplied to the second flow path F2 is increased by increasing the opening of the second valve portion V2 as the actual water temperature rises.

Next, when the actual water temperature further rises and the actual water temperature exceeds a predetermined value, the third supply mode M3 is started, and the opening of the third valve unit V3 is started. Thus, when supplying cooling water to the radiator 3, the fan motor 7M is driven and cooling air is supplied to the radiator 3. FIG. Further, when the vehicle speed is sufficient and the cooling air sufficiently hits the radiator 3, or when the water temperature is sufficiently low, the fan motor 7M is not driven.

In particular, in the third supply mode M3, feedforward control FF is started as shown in FIG. 6 in order to obtain an appropriate flow rate without causing hunting. In order to realize this feedforward control FF, as described above, the first heat amount Q1 per unit time as the engine heat amount, the second heat amount Q2 per unit time as the EGR cooler heat amount, and the third heat amount Q3 per unit time The values of ', the fourth heat amount Q4 per unit time as the engine block heat amount, and the fifth heat amount Q5 per unit time as the oil heat amount are acquired.

In the first heat quantity Q1, the second heat quantity Q2, the fourth heat quantity Q4, and the fifth heat quantity Q5, those that give heat quantity to the cooling water are given a positive (plus) sign, and those that take the heat quantity from the cooling number, A negative sign is attached. Further, the third heat quantity Q3 is given a positive (plus) sign when it is dissipated to change it to the target temperature, and a negative (minus) sign when it receives heat. Further, the target heat dissipation amount setting unit 13 obtains the target heat dissipation amount to be radiated from the sum of these heat values (the sum of Q1, Q2, Q3 ', Q4, and Q5) (steps # 04 and # 05).

For example, when the accelerator pedal is depressed and the engine E rotation speed and the load acting on the engine E increase or the EGR rate rises, the fuel consumption in the engine E increases. Along with this, the amount of heat generated in the engine E increases, and the first amount of heat Q1 given (stored) to the cooling water increases. Further, since a part of the exhaust gas of the engine E is supplied to the EGR cooler 1, the EGR cooler 1 gives the cooling water to the cooling water when the rotational speed of the engine E and the load acting on the engine E increase. 2 Heat quantity Q2 also increases.

That is, since the second heat quantity Q2 given to the cooling water in the EGR cooler 1 is proportional to the first heat quantity Q1, it is acquired by a calculation that multiplies the first heat quantity Q1 by a coefficient set in advance as the EGR rate. The first heat quantity Q1 and the second heat quantity Q2 are acquired based on the detection result of the throttle sensor 21.

For example, when the temperature of the engine E rises and heat is given from the oil cooler 2 to the cooling water (when the lubricating oil temperature rises above the actual water temperature), the fifth heat quantity Q5 is the lubricating oil temperature of the lubricating oil and the oil cooler. The amount of lubricating oil supplied to 2, the temperature of the cooling water, and the amount of cooling water are in a relationship. Accordingly, the amount of lubricating oil supplied to the oil cooler 2 is obtained from the discharge pressure of the oil pump 6, the temperature of the lubricating oil is detected by the oil temperature sensor 24, and the fifth heat quantity Q5 is obtained by calculation using these. Is done.

Further, the fourth heat quantity Q4 is acquired from the calculation or table data as described above.

The third heat quantity Q3 'per unit time is the cooling water heat quantity per unit time obtained by dividing the third heat quantity Q3 by the target response time T.

The amount of heat determined by the sum of the first amount of heat Q1, the second amount of heat Q2, the third amount of heat Q3 ', the fourth amount of heat Q4, and the fifth amount of heat Q5 acquired in this way is the amount of heat to be radiated. The target heat release amount setting unit 13 sets the total heat amount obtained by the calculation as the target heat release amount, the opening degree setting unit 14 sets the flow rate of the cooling water supplied to the radiator 3, and the opening degree setting unit 14 sets the flow rate. The target opening degree of the third valve part V3 of the control valve V is set, and based on this setting, the opening degree of the third valve part V3 of the flow rate control valve V is set, and the flow rate control valve V is controlled (# 06). , # 07 step).

As described above, since the water pump WP is driven by the engine E, the discharge amount varies depending on the rotation speed of the engine E (rotation speed per unit time). The amount of heat exchanged by the radiator 3 is affected by the outside air temperature, the cooling water temperature, the amount of air supplied to the radiator 3, the heat radiation efficiency in the radiator 3, and the like described as a radiator model.

Therefore, when the opening degree of the flow rate control valve V is controlled by the opening degree setting unit 14, the outside air temperature detected by the outside air temperature sensor 23 and the air volume of the cooling air for the radiator 3 estimated by the air volume estimating unit 16 The target opening is set based on a radiator model that takes into account the amount of cooling water supplied by the water pump WP and the target water temperature.

An example of the concept of the radiator model is shown in FIG. “Radiator heat dissipation” is determined from a three-dimensional map of “air flow”, “flow rate”, and “difference between water temperature and outside temperature”. Proportional relationship.
In other words, by standardizing “the difference between the water temperature and the outside air temperature per 1 ° C.”, the “radiator heat dissipation per 1 ° C. between the water temperature and the outside air temperature” can be determined from the “air volume” and the “flow rate”. . Therefore, the “flow rate” to be controlled can be obtained by a two-dimensional map of “radiation amount of radiator per 1 ° C. difference between water temperature and outside air temperature” and “air volume” obtained from the relationship between heat reception and radiation. In FIG. 7, the vertical axis (Y axis) is ΔT (target water temperature−outside air temperature) = 1 ° C., and the horizontal axis (X axis) is the air volume. The target heat dissipation amount Ex is the target heat dissipation amount per ΔT = 1 ° C., and is obtained by the equation Ex = (Q1 + Q2 + Q3 ′ + Q4 + Q5) / (target water temperature−outside air temperature).

The air volume estimation unit 16 estimates the air volume Fx when the vehicle is traveling and the air volume Fx when the vehicle is stopped based on the traveling speed of the vehicle and the driving speed of the fan motor 7M. In the target heat release amount setting unit 13, the target heat release amount Ex is set based on the outside air temperature, the target water temperature, and the required heat release amount.

In this way, the calculation for setting the target opening degree is performed based on the air volume Fx and the target heat release amount Ex. Further, as means for setting the target opening, it is conceivable to refer to table data obtained in advance for the opening of the flow control valve V for a plurality of target flow rates.

Then, as shown in FIG. 6, the feedforward control FF is executed, and at the timing when the target response time T has elapsed from the start of the execution, the feedforward control FF is executed and the feedback control FB is executed (two types of control). The control shifts to (control in which control is performed in parallel) (steps # 08 and # 09).

The above-described feedback control FB is assumed to generate a correction coefficient for correcting the opening degree of the flow control valve V and reflect it in the valve control in the control for executing the feedforward control FF. Even in a situation where the feedforward control FF and the feedback control FB are executed in parallel, for example, when the target water temperature changes, the control shifts to the control of only the feedforward control FF.

That is, as shown in FIG. 6, the feedforward control FF is executed until the target response time T elapses from the start of execution, and when the target response time T elapses, the feedforward control FF and the feedback control FB are performed in parallel. (A region indicated by FF + FB in the figure). By executing this control, a value obtained by adding the opening set by the feedforward control FF shown as the FF component in the figure and the opening set by the feedback control FB shown as the FB component in the figure is The opening degree of the flow control valve V is set.

Further, when the target water temperature changes, the feedforward control FF is executed again, and after the target response time T has elapsed from the re-execution of the feedforward control FF, the feedforward control FF and the feedback are similarly performed as described above. By shifting to the control that executes the control FB in parallel, the opening degree set by the feedforward control FF shown as the FF component and the excuse degree set by the feedback control FB shown as the FB component are added. The value is set to the opening degree of the flow control valve V.

This control is repeatedly performed until the engine is reset (basically, the engine E is stopped) (Step # 010).

As can be seen from FIG. 6, it can be understood that the actual water temperature converges to the target water temperature by executing the feedback control FB in parallel.

[Operation / Effect of Embodiment]
As described above, when the cooling water is supplied to the radiator 3 to control the temperature of the engine E, the first heat amount generated with the operation of the engine E is obtained by obtaining the load acting on the engine E by the throttle sensor 21. Since Q1 and the second heat quantity Q2 given to the cooling water from the EGR cooler 1 are required, these heat quantities can be acquired relatively easily.

The third heat quantity Q3 can be acquired from the current water temperature (actual water temperature), the total amount of cooling water set as a constant, the specific heat of the cooling water, and the target water temperature.

Furthermore, the fourth heat quantity Q4 radiated from the engine E can be easily variable based on the actual measurement value based on the outside air temperature. The fifth heat quantity Q5 can be obtained from the lubricating oil temperature, the amount of lubricating oil flowing through the oil cooler 2, the actual water temperature, and the cooling water amount.

From this, the first calorie Q1, the second calorie Q2, the third calorie Q3 ′, the third calorie Q3, the fourth calorie Q4, and the fifth calorie Q5 per unit time are obtained and summed up. The feedforward control FF that sets the amount of heat to be radiated and sets the opening degree of the flow control valve V can be realized simply by obtaining the above.

Also, in this feedforward control FF, the target heat amount is radiated from the cooling water, and the deviation of the water temperature becomes small. However, since the control is based on the amount of heat, the control is difficult to converge. For this reason, the feedforward control FF is executed in parallel at the timing when the target response time T has elapsed from the start of execution of the feedforward control FF, and the detection result of the water temperature sensor S is based on the reduction in the coolant temperature deviation. By correcting the target opening of the flow rate control valve V with the feedback control FB based on the temperature control within the fluctuation range of the cooling water, it is possible to converge the steady deviation, improving the temperature control accuracy and hunting. There is no invitation.

In addition, it is conceivable to control the amount of cooling water supplied with high accuracy by using a water pump driven by an electric motor in order to manage the temperature of the engine E. In the case of setting the flow rate of the cooling water by setting the opening, it is possible to use the water pump WP driven by the engine E, which leads to a reduction in cost.

[Another embodiment]
In addition to the above-described embodiments, the present invention may be configured as follows (the components having the same functions as those of the embodiments are denoted by the same numbers and symbols as those of the embodiments).

(A) In the embodiment, the first flow path F1, the second flow path F2, and the third flow path F3 are formed in parallel. However, instead of this, a part of them may be arranged in series. good. Moreover, you may form the flow path F other than this, and may provide a heat exchanger like a heater core, for example. When the heater core is provided in this way, it is only necessary to set the control form of the heat quantity acquisition unit 12 so that the heat quantity taken from the cooling water by heat exchange in the heater core is reduced from the total heat quantity described in the embodiment. Basically, the temperature management is realized by the control common to the embodiment.

(B) In the embodiment, the flow control valve V includes the first valve portion V1, the second valve portion V2, and the third valve portion V3. However, in the present invention, the flow control valve V is supplied to the radiator 3. Since it is only necessary to be able to control the amount of cooling water, a configuration that can control the flow rate of cooling water only in the first flow path F1 may be used.

(C) The first heat exchanger may be a turbocharger, the second heat exchanger may be an ATF cooler or a heater, and the outside air temperature sensor may use an intake air temperature sensor.

The present invention can be used in a cooling control device that manages the temperature of an internal combustion engine using a coolant.

1 First heat exchanger (EGR cooler)
2 Second heat exchanger (oil cooler)
3 Radiator 10 Control unit (control unit)
12 heat quantity acquisition unit 13 target heat release setting unit 14 opening setting unit 15 opening correction unit E internal combustion engine (engine)
F channel (first channel)
V Flow control valve WP Coolant pump (water pump)
Q1 1st heat quantity Q2 2nd heat quantity Q3 3rd heat quantity Q4 4th heat quantity Q5 5th heat quantity

Claims

A radiator to which the coolant of the internal combustion engine is supplied, a first heat exchanger that exchanges heat with the coolant separately from the radiator, and a coolant pump that is driven by the internal combustion engine to circulate the coolant And a flow rate control valve for setting the flow rate of the coolant, and a control unit for setting the opening degree of the flow rate control valve,
A first heat amount that the internal combustion engine gives to the coolant according to a rotational speed of the internal combustion engine and a load acting on the internal combustion engine; and a second heat amount that the first heat exchanger gives to the coolant. And a third heat quantity that is transferred to change the coolant to the target temperature, and a heat quantity acquisition unit that acquires the third heat quantity, and the first heat quantity, the second heat quantity, and a unit time obtained by the heat quantity acquisition part. A target heat dissipation amount setting unit for setting a target heat dissipation amount based on a value obtained by adding the third heat amount,
The control unit sets a target flow rate of the coolant to be supplied to the radiator based on the target heat dissipation amount set by the target heat dissipation amount setting unit and the heat exchange efficiency in the radiator, and feedforward control is used to set the target flow rate. A cooling control device comprising an opening setting unit for setting a target opening of the flow control valve.
The amount of heat acquired by the heat amount acquisition unit is the fourth heat amount exchanged between the coolant and the block portion of the internal combustion engine, and the second heat provided separately from the radiator and the first heat exchanger. The cooling control device according to claim 1, comprising a temperature difference between a coolant flowing in the exchanger and a heat exchange target, and a fifth heat quantity obtained from the flow rate.
The cooling control device according to claim 2, wherein the second heat exchanger is an oil cooler.
When the deviation between the target heat release amount and the amount of heat acquired by the heat amount acquisition unit falls below a predetermined threshold value, a control is performed to reduce the deviation by feedback control while executing feedforward control. Item 4. The cooling control device according to any one of Items 1 to 3.
5. The target response time for managing the temperature of the internal combustion engine is set, and the opening setting unit sets the target opening of the flow control valve based on the target response time. The cooling control device according to one item.