JP6311503B2 - Cooling device for internal combustion engine and cooling method for internal combustion engine - Google Patents

Description

  The present invention relates to a cooling device for an internal combustion engine and a cooling method for the internal combustion engine, and more particularly to a technique for reducing fluctuations in the outlet water temperature of the internal combustion engine without being affected by the ambient temperature.

  An internal combustion engine mounted on a vehicle is provided with a cooling flow path through which cooling water flows, and is controlled so that the temperature of the internal combustion engine becomes a desired temperature by flowing cooling water through the cooling flow path. . When it is desired to lower the temperature of the internal combustion engine, the temperature of the cooling water is lowered by passing the cooling water through a heat exchanger (a radiator or the like).

  When the cooling water whose temperature has risen is suddenly introduced into the heat exchanger at room temperature when the internal combustion engine is started, the heat exchanger is subjected to a thermal shock (also called “thermal shock”) due to the temperature difference before and after the introduction of the cooling water. Will receive. In Patent Document 1, in order to mitigate thermal shock, the temperature of the cooling water that passes through the heat exchanger is detected and the temperature of the cooling water that is supplied to the heat exchanger so that the temperature difference does not increase. Is disclosed.

JP 2008-37302 A

  However, in the conventional example disclosed in Patent Document 1 described above, in order to reduce the thermal shock generated in the heat exchanger, the temperature is raised by flowing cooling water through the heat exchanger. Even when it is desired to raise the temperature, a part of the cooling water is supplied to the heat exchanger, which causes a problem that the temperature rise of the internal combustion engine is delayed.

  Further, in order to control the outlet water temperature of the internal combustion engine to be the target temperature, the temperature deviation between the outlet temperature and the ambient temperature is obtained. At this time, since the ambient temperature is set to room temperature (for example, 25 ° C.), for example, when the ambient temperature is lower than room temperature such as 10 ° C., or when the ambient temperature is higher than room temperature such as 40 ° C. The amount of heat released by the heat exchanger increases or decreases. For this reason, overshoot, undershoot, hunting, etc. occur in the outlet temperature of the internal combustion engine, and it becomes difficult to control the outlet water temperature of the internal combustion engine to be the target temperature.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an internal combustion engine capable of controlling the temperature of cooling water supplied to the internal combustion engine to an appropriate temperature. An object of the present invention is to provide an engine cooling apparatus and an internal combustion engine cooling method.

  In order to achieve the above-described object, the present invention provides a cooling channel through which cooling water for cooling an internal combustion engine flows, and a heat exchanger provided with a heat exchanger for cooling water cooling provided on the outlet side of the cooling channel. It has a switching part which branches into at least one of an exchange channel and a bypass channel where a heat exchanger is not arranged. Also, distribution of the cooling water flow rate to the heat exchange flow path and the bypass flow path in the inlet temperature detection section that detects the inlet temperature of the heat exchanger, the outlet temperature detection section that detects the outlet temperature, and the switching section is controlled. A control unit. The control unit obtains a temperature deviation from the difference between the inlet temperature and the target temperature of the internal combustion engine outlet, calculates a difference between the inlet temperature and the outlet temperature, obtains a difference temperature, and based on the temperature deviation and the difference temperature The aperture ratio of the switching unit is obtained.

  In the internal combustion engine cooling apparatus and internal combustion engine cooling method according to the present invention, the temperature deviation is obtained from the difference between the inlet temperature of the heat exchanger and the target temperature of the outlet of the internal combustion engine, and the inlet temperature and the outlet temperature of the heat exchanger. And the opening ratio of the switching unit is obtained based on the temperature deviation and the difference temperature, so that the temperature of the cooling water supplied to the internal combustion engine can be controlled to an appropriate temperature.

1 is a block diagram showing a configuration of an internal combustion engine including a cooling device for an internal combustion engine according to an embodiment of the present invention. It is a block diagram which shows the detailed structure of the control part used for the cooling device of the internal combustion engine shown in FIG. It is explanatory drawing which shows the aperture ratio calculation map which shows the relationship between sensitivity data, differential temperature (DELTA) T, and an aperture ratio employ | adopted with the cooling device of the internal combustion engine which concerns on one Embodiment of this invention. It is explanatory drawing which shows the angle calculation map which shows the relationship between the opening rate of a three-way valve, and an angle employ | adopted with the cooling device of the internal combustion engine which concerns on one Embodiment of this invention. It is a flowchart which shows the process sequence by the cooling device of the internal combustion engine which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an internal combustion engine including a cooling device according to an embodiment of the present invention. As shown in FIG. 1, the cooling device according to the present embodiment includes a cooling flow path L1 that supplies cooling water to the internal combustion engine 11, a circulation pump 13 that circulates the cooling water in the cooling flow path L1, And a three-way valve 12 (switching unit) that is provided at the outlet end of the cooling flow path L1 and branches the cooling water that has passed through the internal combustion engine 11 into two systems.

  The three-way valve 12 distributes and outputs the cooling water supplied from the cooling flow path L1 to the bypass flow path L2 and the heat exchange flow path L3. The bypass channel L2 is connected to the inlet side of the circulation pump 13, and the heat exchange channel L3 is connected to the inlet side of the circulation pump 13 via a heat exchanger 14 (for example, a radiator) for cooling the cooling water. It is connected to the. That is, the three-way valve 12 (switching means) is provided on the outlet side of the cooling flow path L1, and the cooling flow path L1 is connected to the heat exchange flow path L3 in which the heat exchanger 14 for cooling water cooling is disposed, and the heat. A function of branching to at least one of the bypass flow paths L2 where the exchanger 14 is not disposed is provided.

  Further, in the cooling flow path L1 in the vicinity of the outlet of the internal combustion engine 11, a first temperature detection unit 21 (inlet temperature detection unit) that detects the temperature of the cooling water flowing through the cooling flow path L1 is provided. In addition, since temperature T1 detected by the 1st temperature detection part 21 is inlet side temperature of the heat exchanger 14, it is hereafter called inlet temperature T1. And since the exit edge part of the cooling flow path L1 is connected to the inlet_port | entrance of the heat exchanger 14 via the heat exchange flow path L3, the temperature detected by the 1st temperature detection part 21 is the heat exchanger 14. It becomes a temperature equivalent to the inlet temperature T1 of the cooling water supplied to. On the other hand, in the heat exchange flow path L3 near the outlet of the heat exchanger 14, a second temperature detection unit 22 (outlet temperature detection unit) that detects an outlet temperature T2 that is the temperature of the cooling water that has passed through the heat exchanger 14 is provided. Is provided. Note that “detecting temperature” is a concept including direct measurement by a sensor and estimation based on factors such as a cooling water flow rate.

  Furthermore, the control part 23 which acquires the inlet temperature T1 and the outlet temperature T2, and controls the opening degree of the three-way valve 12 based on these temperature data is provided.

  The detailed configuration of the control unit 23 will be described below with reference to the block diagram shown in FIG. The controller 23 calculates a deviation (temperature deviation) between the temperature of the cooling water output from the internal combustion engine 11 (that is, the inlet temperature T1) and the target temperature T1ref of the inlet temperature T1, and the subtraction. The multiplier 31 includes a multiplier 32 that multiplies a preset gain and outputs sensitivity data. Furthermore, a subtractor 33 is provided for inputting the inlet temperature T1 and the outlet temperature T2 of the heat exchanger 14 and calculating the difference temperature ΔT between them.

  Further, based on the sensitivity data output from the multiplier 32 and the difference temperature ΔT, the opening ratio calculation for obtaining the opening ratio of the three-way valve 12 (the opening ratio for determining the amount of cooling water supplied to the heat exchange flow path L3). Unit 34, an angle calculation unit 35 for obtaining an angle of the three-way valve 12 based on the opening ratio obtained by the opening ratio calculation unit 34, and a memory 36 (map storage unit). In the memory 36, an opening ratio calculation map showing the correspondence between the sensitivity data, the difference temperature ΔT, and the opening ratio, which is used for the calculation of the opening ratio calculation unit 34, and the opening ratio of the three-way valve 12 and the three-way valve 12 An angle calculation map indicating a correspondence relationship with the angle is stored.

  FIG. 3 is an explanatory diagram showing the specific contents of the aperture ratio calculation map, in which the aperture ratio is set for the sensitivity data and the difference temperature ΔT. Therefore, when sensitivity data and differential temperature ΔT are input, an aperture ratio corresponding to the sensitivity data and differential temperature ΔT is obtained. More specifically, the aperture ratio is obtained based on the sensitivity data, and the aperture ratio can be corrected by the differential temperature ΔT. FIG. 4 is an explanatory diagram showing the specific contents of the angle calculation map, and the angle of the three-way valve is set with respect to the opening ratio of the three-way valve 12.

  That is, the control unit 23 obtains a temperature deviation from the difference between the inlet temperature T1 and the target temperature (T1ref) of the internal combustion engine outlet, and calculates a difference between the inlet temperature T1 and the outlet temperature T2 to obtain a difference temperature ΔT. , A function of obtaining the opening ratio of the three-way valve 12 (switching unit) based on the temperature deviation and the difference temperature ΔT.

  The control unit 23 can be configured as an integrated computer including a central processing unit (CPU), storage means such as a RAM, a ROM, and a hard disk.

  Next, with reference to the flowchart shown in FIG. 3, the processing procedure of the cooling device for the internal combustion engine according to the present embodiment will be described. This process is repeatedly executed every preset calculation cycle.

  First, in step S11 of FIG. 3, the internal combustion engine 11 is started. At this time, since the circulation pump 13 starts driving, the cooling water flows into the cooling flow path L1 and the internal combustion engine 11 is cooled. Further, the outlet of the three-way valve 12 is opened at the bypass flow path L2 side and closed at the heat exchange flow path L3 side. Accordingly, the cooling water flowing through the cooling flow path L1 is returned to the circulation pump 13 via the bypass flow path L2. As a result, the temperature of the cooling water rises, and the temperature of the cooling water after passing through the internal combustion engine 11 rises to 100 ° C., for example. Thereafter, the temperature of the lubricating oil (internal combustion engine oil, transmission oil, etc.) used for the internal combustion engine and the drive mechanism rises, so that the friction of the lubricating oil decreases and the fuel consumption rate can be improved.

  Thereafter, when the rotational speed and torque of the internal combustion engine 11 increase, knocking occurs in the internal combustion engine 11 and the fuel consumption rate deteriorates. Therefore, it is desired to reduce the temperature of the internal combustion engine 11 in order to prevent knocking. Therefore, in step S <b> 12, the control unit 23 opens the heat exchange flow path L <b> 3 side of the three-way valve 12 and starts supplying cooling water to the heat exchanger 14. At this time, the opening ratio of the three-way valve 12 is set to an initially set opening ratio.

  In step S <b> 13, the control unit 23 acquires the inlet temperature T <b> 1 measured by the first temperature detection unit 21. When the inlet temperature T1 is acquired, the temperature deviation between the inlet temperature T1 and the target temperature T1ref is calculated by the subtractor 31 shown in FIG. 2, and this temperature deviation is multiplied by the gain by the multiplier 32. After that, it is supplied to the aperture ratio calculation unit 34 as sensitivity data. In step S14, the opening ratio calculation unit 34 obtains the opening ratio of the three-way valve 12 on the heat exchange flow path L3 side by applying the sensitivity data to the opening ratio calculation map shown in FIG.

  In step S <b> 15, the control unit 23 acquires the outlet temperature T <b> 2 measured by the second temperature detection unit 22. When the outlet temperature T2 is acquired, the difference temperature ΔT between the outlet temperature T2 and the inlet temperature T1 is calculated by the subtractor 33 shown in FIG. 2, and this difference temperature ΔT is supplied to the opening ratio calculation unit 34. The

  In step S16, the aperture ratio calculation unit 34 corrects the aperture ratio obtained in the process of step S14 by applying it to the aperture ratio calculation map shown in FIG. 3 based on the difference temperature ΔT.

  The corrected opening rate is controlled so that the cooling water supplied from the three-way valve 12 has a flow rate corresponding to the differential temperature ΔT after passing through the heat exchanger 14. That is, when it is determined that the ambient temperature is low (for example, 10 ° C.) and the amount of heat released by the heat exchanger 14 is large, the opening ratio is decreased and the flow rate of the cooling water passing through the heat exchanger 14 is decreased. . On the contrary, when it is determined that the ambient temperature is high (for example, 40 ° C.) and the amount of heat released by the heat exchanger 14 is small, the cooling water passing through the heat exchanger 14 with an increased aperture ratio is used. Increase the flow rate. By doing so, the temperature of the cooling water supplied to the internal combustion engine 11 can be maintained at a substantially constant temperature, and the internal combustion engine 11 can be operated stably. Then, the corrected aperture ratio data is output to the angle calculator 35.

  In step S17, the angle calculation unit 35 obtains the valve angle of the three-way valve 12 by fitting the opening ratio corrected in the process of step S16 to the angle calculation map. Thereafter, in step S18, this angle data is output to the three-way valve 12 shown in FIG. 1, and the angle of the valve of the three-way valve 12 is controlled.

  Thus, in the cooling device for an internal combustion engine according to the present embodiment, the coolant temperature on the outlet side of the internal combustion engine 11, that is, the inlet temperature T1 of the heat exchanger 14 is set to the preset target temperature T1ref. The opening ratio of the three-way valve 12 is obtained. Further, a difference temperature ΔT between the inlet temperature T1 and the outlet temperature T2 of the heat exchanger 14 is calculated, and the opening ratio is corrected by the difference temperature ΔT. Then, the angle of the three-way valve 12 is controlled so that the corrected opening ratio is obtained.

  Therefore, the flow rate of the cooling water supplied to the heat exchanger 14 is controlled according to the difference temperature ΔT between the inlet temperature T1 and the outlet temperature T2 of the heat exchanger 14. For this reason, for example, when the ambient temperature is low and the amount of heat released by the heat exchanger 14 is large, the amount of cooling water supplied to the heat exchanger 14 is reduced. As a result, the temperature of the cooling water flowing into the internal combustion engine 11 can be maintained at a stable temperature, and it is possible to avoid the occurrence of the problem that the cooling water temperature is lowered and the efficiency of the internal combustion engine is reduced. It becomes.

  Further, since the opening ratio calculation map is stored in the memory 36 and the opening ratio of the three-way valve 12 is set with reference to the opening ratio calculation map, the opening ratio can be calculated without applying much calculation load. .

  In the above-described embodiment, the example in which the opening ratio is corrected using the difference temperature ΔT between the inlet temperature T1 and the outlet temperature T2 has been described. However, the present invention is not limited to this example. The gain of the multiplier 32 shown in FIG. 2 may be changed based on ΔT. Even in such a configuration, the same effects as those of the above-described embodiment can be obtained.

  The internal combustion engine cooling device and the internal combustion engine cooling method of the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part has the same function. It can be replaced with any configuration.

11 Internal combustion engine 12 Three-way valve (switching part)
13 Circulation Pump 14 Heat Exchanger 21 First Temperature Detection Unit (Inlet Temperature Detection Unit)
22 Second temperature detector (exit temperature detector)
23 Control Unit 31 Subtractor 32 Multiplier 33 Subtractor 34 Aperture Ratio Calculation Unit 35 Angle Calculation Unit 36 Memory (Map Storage Unit)
L1 Cooling channel L2 Bypass channel L3 Heat exchange channel

Claims (3)

A cooling flow path through which cooling water for cooling the internal combustion engine flows;
Provided on the outlet side of the cooling flow path, the cooling flow path is at least one of a heat exchange flow path in which a heat exchanger for cooling water cooling is disposed and a bypass flow path in which the heat exchanger is not disposed. A switching unit for branching;
A circulation pump for sending the cooling water that has passed through the heat exchange channel and the bypass channel to the cooling channel;
An inlet temperature detector that detects an inlet temperature that is a temperature of cooling water that is output from the internal combustion engine and supplied to the heat exchanger;
An outlet temperature detector that detects an outlet temperature that is a temperature of cooling water output from the heat exchanger;
A control unit for controlling distribution of the cooling water flow rate to the heat exchange channel and the bypass channel in the switching unit,
The controller is
Find the temperature deviation from the difference between the inlet temperature and the target temperature of the internal combustion engine outlet, and calculate the difference between the inlet temperature and the outlet temperature to obtain the difference temperature,
A cooling device for an internal combustion engine, wherein an opening ratio of the switching unit is obtained based on the temperature deviation and the differential temperature. A map storage unit that stores an opening ratio calculation map indicating correspondence between the temperature deviation, the difference temperature, and an opening ratio for determining a flow rate of cooling water to the heat exchange flow path in the switching unit; ,
2. The cooling device for an internal combustion engine according to claim 1, wherein the control unit applies the temperature deviation and the differential temperature to the opening rate calculation map to obtain an opening rate of the switching unit. A step of flowing cooling water through a cooling flow path for cooling the internal combustion engine when driving the internal combustion engine;
Detecting an inlet temperature which is a temperature of cooling water output from the internal combustion engine and supplied to the heat exchanger, and obtaining a temperature deviation which is a difference between the detected inlet temperature and a target temperature of the internal combustion engine outlet;
Detecting an outlet temperature which is a temperature of cooling water output from the heat exchanger, and obtaining a difference temperature between the detected outlet temperature and the inlet temperature;
Provided on the outlet side of the cooling flow path, the cooling flow path is at least one of a heat exchange flow path in which a heat exchanger for cooling water cooling is disposed and a bypass flow path in which the heat exchanger is not disposed. A method for cooling an internal combustion engine, comprising: obtaining an opening ratio of the switching unit to be branched to the heat exchanger side based on the temperature deviation and the differential temperature.

Images