JP2010209818A - Cooling device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology performing oil temperature control while satisfying a requirement to a heater and further reducing a workload on a pump, in a cooling device for an internal combustion engine. <P>SOLUTION: This cooling device for the internal combustion engine includes: an oil cooler circulation passage 6 circulating cooling water from the internal combustion engine 1 to an oil cooler 5; a radiator bypass passage 7 allowing the cooling water led to flow out from the internal combustion engine 1 to bypass a radiator 3; a heater circulation passage 9 circulating the cooling water from the internal combustion engine 1 to the heater 8; and a cross valve 11 provided in a portion where the outlet of the oil cooler circulation passage 6 is connected to the outlet of the radiator bypass passage 7 and the cooling water is supplied to a side downstream of the heater 8 in the heater circulation passage 9, and simultaneously controlling a cooling water flow rate in the oil cooler circulation passage 6 and a cooling water flow rate in the radiator bypass passage 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling device for an internal combustion engine.

  In a cooling device for an internal combustion engine, a technique is disclosed in which a valve is disposed in a radiator bypass passage, and the cooling water flow rate in the radiator bypass passage is adjusted by the valve to increase the cooling water flow rate to the heater (for example, Patent Documents). 1).

JP 2000-289444 A JP 2007-107522 A JP 2002-227648 A JP 2007-224819 A JP 2007-224821 A JP 2003-322019 A

  However, in the above technology, the flow rate of the cooling water to the oil cooler is not taken into consideration, and the oil temperature control cannot be performed while satisfying the heater requirement, and the work amount of the pump is reduced. A sufficient effect could not be obtained.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique for controlling the oil temperature while satisfying the heater requirement and further reducing the work of the pump in the cooling device for the internal combustion engine. It is in.

In the present invention, the following configuration is adopted. That is, the present invention
An oil cooler circulation passage for circulating a cooling medium from the internal combustion engine to the oil cooler;
A radiator bypass passage for bypassing the radiator to the cooling medium flowing out of the internal combustion engine;
A heater circulation passage for circulating a cooling medium from the internal combustion engine to the heater;
The outlet of the oil cooler circulation passage and the outlet of the radiator bypass passage are connected to each other, and the cooling medium flow rate in the oil cooler circulation passage is provided at a portion that supplies the cooling medium downstream of the heater in the heater circulation passage. A three-way valve for simultaneously controlling the coolant flow rate in the radiator bypass passage;
A cooling device for an internal combustion engine, comprising:

  According to the present invention, the cooling medium flow rate in the oil cooler circulation passage and the cooling medium flow rate in the radiator bypass passage are simultaneously controlled by the three-way valve, and these cooling media are supplied to the downstream side of the heater in the heater circulation passage. Thus, not only the coolant flow rate to the oil cooler is adjusted by the three-way valve, but also the coolant flow rate to the heater is adjusted by the three-way valve. Therefore, the heater request can be satisfied by adjusting the coolant flow rate to the heater by the three-way valve, and the oil temperature can be controlled by adjusting the coolant flow rate to the oil cooler.

  Further, the cooling medium from the oil cooler circulation passage and the radiator bypass passage is supplied to the downstream side of the heater in the heater circulation passage. Thereby, the cooling medium flow rate of the heater circulation passage can be sufficiently increased. Therefore, it is not necessary to increase the coolant flow rate in the heater circulation passage by the pump, and the work of the pump can be reduced.

  According to the present invention, in the cooling device for an internal combustion engine, the oil temperature control can be performed while satisfying the heater requirement, and the work of the pump can be reduced.

1 is a diagram illustrating a schematic configuration of an internal combustion engine and a cooling system thereof according to Embodiment 1. FIG. 3 is a flowchart showing a coolant flow control routine 1 according to the first embodiment. 6 is a flowchart showing a cooling water flow rate control routine 2 according to the first embodiment. 5 is a flowchart showing a coolant flow control routine 3 according to the first embodiment. 7 is a flowchart showing a coolant flow control routine 4 according to the first embodiment. 7 is a flowchart illustrating a coolant flow control routine 5 according to the first embodiment. 6 is a flowchart showing a coolant flow control routine 6 according to the first embodiment. 7 is a flowchart showing a coolant flow control routine 7 according to the first embodiment. 7 is a flowchart showing a cooling water flow rate control routine 8 according to the first embodiment.

  Specific examples of the present invention will be described below.

<Example 1>
FIG. 1 shows a schematic configuration of an internal combustion engine to which the cooling device for an internal combustion engine of the present invention is applied and its cooling system. An internal combustion engine 1 shown in FIG. 1 is a water-cooled four-stroke cycle diesel engine having four cylinders 2 that form a combustion chamber together with a piston. The internal combustion engine 1 is mounted on a vehicle.

  The internal combustion engine 1 is provided with a radiator circulation passage 4 through which cooling water flows from the internal combustion engine 1 to the radiator 3. The radiator 3 cools the cooling water by exchanging heat between the cooling water and the air in the radiator circulation passage 4. In this embodiment, the cooling water is described as an example, but other cooling media may be used in the present invention.

  The internal combustion engine 1 is provided with an oil cooler circulation passage 6 through which cooling water flows from the internal combustion engine 1 to the oil cooler 5. The oil cooler cools the oil by exchanging heat between the oil in the oil cooler 5 and the cooling water in the oil cooler circulation passage 6.

  The internal combustion engine 1 is provided with a radiator bypass passage 7 for bypassing the radiator 3 with cooling water flowing out from the internal combustion engine 1.

  The internal combustion engine 1 is provided with a heater circulation passage 9 through which cooling water flows from the internal combustion engine 1 to the heater 8. The heater 8 is for heating the vehicle interior and generates heat. In order to prevent the heater 8 from generating excessive heat, cooling water is supplied from the heater circulation passage 9 and cooled.

A three-way valve 11 is arranged at a portion for connecting the outlet of the oil cooler circulation passage 6 and the outlet of the radiator bypass passage 7 and supplying cooling water to the downstream side of the heater 8 of the heater circulation passage 9 through the communication passage 10. Yes. The three-way valve 11 has an oil cooler circulation passage side valve and a radiator bypass passage side valve, and the coolant flow rate of the oil cooler circulation passage 6 can be adjusted by the oil cooler circulation passage side valve, and the radiator bypass passage side valve The coolant flow rate in the radiator bypass passage 7 can be adjusted. Therefore, the three-way valve 11 can simultaneously control the coolant flow rate in the oil cooler circulation passage 6 and the coolant flow rate in the radiator bypass passage 7. Due to the three-way valve 11, the cooling water in the oil cooler circulation passage 6 and the radiator bypass passage 7 flows into the heater circulation passage 9 via the communication passage 10.

  A heater valve 12 is disposed downstream of the heater 8 in the heater flow passage 9 and upstream of the connection position with the communication passage 10. The heater valve 12 can adjust the coolant flow rate in the heater circulation passage 9.

  The outlet on the downstream side of the outlet of the radiator circulation passage 4 and the connection position of the heater circulation passage 9 with the communication passage 10 communicates with the thermostat 13. When the internal combustion engine 1 is in a warm-up operation state, the thermostat 13 closes the radiator circulation passage 4 and causes only the heater circulation passage 9 to circulate cooling water. On the other hand, when the internal combustion engine 1 is in a normal operation state, the radiator circulation passage 4 is opened, and the cooling water in both the radiator circulation passage 4 and the heater circulation passage 9 is circulated. Since the thermostat 13 in this embodiment is a simple one that controls only the opening and closing of the radiator circulation passage 4, it is possible to improve reliability, reduce costs, and reduce weight.

  A junction passage 14 is provided on the downstream side of the thermostat 13. A water pump 15 is disposed in the merge passage 14. The water pump 15 pumps up cooling water flowing through the merge passage 14 and pumps it to the internal combustion engine 1. These constitute a cooling system for the internal combustion engine 1.

  The internal combustion engine 1 configured as described above is provided with an ECU 16 that is an electronic control unit for controlling the internal combustion engine 1. The ECU 16 is a unit that controls the operation state of the internal combustion engine 1 in accordance with the operation conditions of the internal combustion engine 1 and the request of the driver. Each actuator of the three-way valve 11 and the heater valve 12 is connected to the ECU 16 via electric wiring, and these devices are controlled by the ECU 16.

  The internal combustion engine 1 is in several states depending on its operating state. For example, there may be a warm-up operation state in which the vehicle travels at a low speed after the cold start. In this case, a high capacity of the heater 8 is required, but the engine speed and the cooling water temperature are low, and the performance of the heater 8 is difficult to obtain. In this case, the cooling water temperature is low, and the thermostat 13 closes the radiator circulation passage 4. The heater valve 12 is opened to the maximum. Since the three-way valve 11 uses the oil cooler 5 as an oil warmer, the oil cooler flow passage side valve is greatly opened, and the internal combustion engine 1 does not require much cooling, so the radiator bypass passage side valve is opened or closed to a minimum. To do.

  For example, there may be a middle-speed and medium-load operation state. In this case, the cooling water temperature rises to about 80 ° C. to 90 ° C., the thermostat 13 opens the radiator circulation passage 4, and the cooling water circulates through the radiator 3. In this case, the capacity of the heater 8 depends on the outside air temperature, but is required to be moderate. Therefore, the heater valve 12 is opened at the minimum required opening. Since the oil temperature of the three-way valve 11 is about 80 ° C. to 90 ° C. and cooling by the oil cooler 5 is unnecessary, the oil cooler circulation passage side valve is closed, and the radiator 3 performs cooling of the internal combustion engine 1. The bypass passage side valve is closed.

For example, there may be a high-speed and high-load operation state. In this case, the thermostat 13 opens the radiator circulation passage 4, and the cooling water circulates through the radiator 3. In this case, since the cooling performance in the radiator 3 is most required, the heater valve 12 is closed in order to increase the cooling water flow rate in the radiator circulation passage 4. In the three-way valve 11, the oil temperature becomes 100 ° C. or more and the cooling water is circulated to the oil cooler 5 to stabilize the oil temperature, so that the oil cooler circulation passage side valve is opened to the maximum, and the cooling performance of the radiator 3 is the highest. As required, the radiator bypass passage side valve is closed.

  Next, the cooling water flow rate control routine 1 according to this embodiment will be described. FIG. 2 is a flowchart showing a cooling water flow rate control routine 1 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In S101, various output values from various sensors and the like are taken into the ECU 16. Examples of the output value include engine speed, engine load, cooling water temperature, oil temperature, heater command value, room temperature, outside air temperature, and the like. Conventionally, output values such as heater command values have not been captured by the ECU 16, but in this embodiment, these output values and internal combustion engine information are unified and used for control.

  In S102, the openings of the three-way valve 11 and the heater valve 12 are searched from a map obtained in advance according to the output value taken in in S101.

  In S103, the three-way valve 11 and the heater valve 12 are controlled to the opening degree searched in S102.

  In this way, by executing this routine, it is possible to control the cooling water flow rate optimum for the internal combustion engine 1. Thereby, indoor comfort, fuel consumption, and exhaust can be maintained in an optimal state.

  The cooling water flow rate may be controlled by a method other than the above. For example, the following may be used.

  Next, the cooling water flow rate control routine 2 according to this embodiment will be described. FIG. 3 is a flowchart showing a cooling water flow rate control routine 2 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In S201, the ECU 16 takes in the output values of the cooling water temperature and the engine speed.

  In S202, it is determined whether or not the cooling water temperature taken in in S201 is lower than a predetermined value. The predetermined value is a predetermined value, and is a threshold value that eliminates the need to circulate cooling water through the radiator bypass passage 7 when the predetermined value is higher. If a positive determination is made in S202, the process proceeds to S203. If a negative determination is made in S202, the process proceeds to S205.

  In S203, the openings of the three-way valve 11 and the heater valve 12 are retrieved from a map obtained in advance according to the engine speed taken in in S201. In this map, the opening degree of the heater valve 12 is reduced as the engine speed increases, and the coolant flow rate to the heater 8 is reduced.

  In S204, the three-way valve 11 and the heater valve 12 are controlled to the opening degree searched in S203.

  On the other hand, in S205, the radiator bypass passage side valve of the three-way valve 11 is closed.

  By executing this routine in this way, if the flow rate of the coolant to the heater 8 increases with the increase in the engine speed, the flow becomes more than necessary and is wasted. Therefore, the heater valve 12 is adjusted in accordance with the increase in the engine speed. The amount of cooling water flow to the heater 8 can be reduced.

  The cooling water flow rate control routine 3 according to this embodiment will be described. FIG. 4 is a flowchart showing a cooling water flow rate control routine 3 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In this routine, after the processing of step S204, as S301, the opening degree of the heater valve 12 is reduced and the cooling water flow rate to the heater 8 is reduced in accordance with the rise of the cooling water temperature. The other steps are the same as those in the cooling water flow rate control routine 2 and will not be described. Note that the map in S203 may be considered by adding the coolant temperature in addition to the engine speed.

  In this way, when the cooling water temperature rises by executing this routine, if the flow rate of the cooling water to the heater 8 is increased in consideration of the heat radiation performance of the heater 8, the flow becomes more than necessary and is wasted. As the water temperature rises, the opening degree of the heater valve 12 can be reduced to reduce the coolant flow rate to the heater 8.

  The cooling water flow rate control routine 4 according to this embodiment will be described. FIG. 5 is a flowchart showing a cooling water flow rate control routine 4 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In this routine, instead of S201, the output values of the cooling water temperature, the engine speed, and the room temperature are taken into the ECU 16 in S401. Moreover, after the process of step S301, as S402, the opening degree of the heater valve 12 is reduced and the cooling water flow rate to the heater 8 is reduced in accordance with the rise in the room temperature. The other steps are the same as those in the cooling water flow rate control routine 3, and will not be described.

  In this way, by executing this routine, when the room temperature is high, the demand for the heater 8 is not high. Therefore, if the flow rate of the cooling water to the heater 8 is increased, the flow rate becomes unnecessarily high and is wasted. As the temperature rises, the opening degree of the heater valve 12 can be reduced and the flow rate of the cooling water to the heater 8 can be reduced.

  The cooling water flow rate control routine 5 according to this embodiment will be described. FIG. 6 is a flowchart showing a cooling water flow rate control routine 5 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In this routine, instead of S201, the output values of the coolant temperature, the engine speed and the outside air temperature are taken into the ECU 16 in S501. Moreover, after the process of step S301, as S502, the opening degree of the heater valve 12 is reduced and the cooling water flow rate to the heater 8 is reduced in accordance with the rise in the outside air temperature. The other steps are the same as those in the cooling water flow rate control routine 3, and will not be described.

  In this way, by executing this routine, when the outside air temperature is high, the demand for the heater 8 is not high. Therefore, if the flow rate of the cooling water to the heater 8 is increased, the flow rate becomes more than necessary and is wasted. The opening degree of the heater valve 12 can be reduced according to the temperature rise, and the coolant flow rate to the heater 8 can be reduced.

  The cooling water flow rate control routine 6 according to the present embodiment will be described. FIG. 7 is a flowchart showing a cooling water flow rate control routine 6 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In this routine, instead of S201, the output values of the cooling water temperature, the engine speed, the room temperature, and the outside air temperature are taken into the ECU 16 in S601. Further, after the process of step S301, as S602, the opening degree of the heater valve 12 is reduced and the heater 8 is reduced as the difference temperature ΔT (= indoor temperature−outside air temperature) obtained by subtracting the outside air temperature from the room temperature increases. Reduce the coolant flow rate. The other steps are the same as those in the cooling water flow rate control routine 3, and will not be described.

  Thus, by executing this routine, when the difference temperature ΔT increases, the demand for the heater 8 is not high, and if the flow rate of the cooling water to the heater 8 increases, the flow rate becomes higher than necessary and is wasted. Therefore, the opening degree of the heater valve 12 can be reduced and the coolant flow rate to the heater 8 can be reduced as the differential temperature ΔT increases.

  The cooling water flow rate control routine 7 according to this embodiment will be described. FIG. 8 is a flowchart showing a coolant flow control routine 7 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In this routine, instead of S201, the coolant temperature, the engine speed, and the engine load output values are taken into the ECU 16 in S701. Further, after the processing of step S301, as S702, the opening degree of the heater valve 12 is reduced in accordance with the engine load increase, and the coolant flow rate to the heater 8 is reduced. The other steps are the same as those in the cooling water flow rate control routine 3, and will not be described.

  In this way, by executing this routine, when the engine load increases, the cooling performance by the radiator 3 is required and the flow rate of the cooling water flowing to the heater 8 is relatively large, so the cooling water flow rate to the radiator 3 is As the engine load increases, the opening degree of the heater valve 12 can be reduced to reduce the cooling water flow rate to the heater 8 so that the cooling water flow rate to the heater 8 is reduced.

  Next, the cooling water flow rate control routine 8 according to this embodiment will be described. FIG. 9 is a flowchart showing a cooling water flow rate control routine 8 according to this embodiment. This routine is repeatedly executed by the ECU 16 at regular intervals.

  In S801, an output value for detecting that the room is being cooled is taken into the ECU 16.

  In S802, it is determined whether or not the output value fetched in S801 is in cooling. If a negative determination is made in S802, the process proceeds to S803. If a positive determination is made in S802, the process proceeds to S804.

  In S803, cooling water flow rate control is performed. For example, the cooling water flow rate control routines 1 to 7 can be used.

  On the other hand, in S804, the heater valve 12 is closed.

  In this way, by executing this routine, when the room is being cooled, the heater 8 does not generate heat, and it is useless if the cooling water flows to the heater 8. Therefore, when the room is being cooled. The heater valve 12 can be closed so that the cooling water does not flow to the heater 8.

  According to the present embodiment described above, the three-way valve 11 simultaneously controls the cooling water flow rate in the oil cooler circulation passage 6 and the cooling water flow rate in the radiator bypass passage 7, and these cooling waters are supplied from the heater 8 in the heater circulation passage 9. Is also supplied downstream. Therefore, not only the cooling water flow rate to the oil cooler 5 is adjusted by the three-way valve 11, but also the cooling water flow rate to the heater 8 is adjusted by the three-way valve 11. Therefore, the heater request can be satisfied by adjusting the cooling water flow rate to the heater 8 by the three-way valve 11, and the oil temperature can be controlled by adjusting the cooling water flow rate to the oil cooler 5.

Further, cooling water from the oil cooler circulation passage 6 and the radiator bypass passage 7 is supplied to the downstream side of the heater 8 in the heater circulation passage 9. Therefore, the cooling water flow rate of the heater circulation passage 9 can be sufficiently increased. Therefore, it is not necessary to increase the coolant flow rate in the heater circulation passage 9 by the water pump 15, and the work amount of the water pump 15 can be reduced. As a result, the mechanical loss due to the large amount of work of the water pump 15 can be reduced, the fuel consumption can be improved, the startability at low temperature and the output at the time of high rotation can be improved, and further the water pump The cavitation of 15 suction parts can be prevented, durability can be improved, and the cooling water flow rate can be prevented from decreasing when the cooling water temperature is high due to high rotation.

  The cooling apparatus for an internal combustion engine according to the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the gist of the present invention.

1 Internal combustion engine 2 Cylinder 3 Radiator 4 Radiator flow passage 5 Oil cooler 6 Oil cooler flow passage 7 Radiator bypass passage 8 Heater 9 Heater flow passage 10 Communication passage 11 Three-way valve 12 Heater valve 13 Thermostat 14 Merge passage 15 Water pump 16 ECU

Claims (1)

An oil cooler circulation passage for circulating a cooling medium from the internal combustion engine to the oil cooler;
A radiator bypass passage for bypassing the radiator to the cooling medium flowing out of the internal combustion engine;
A heater circulation passage for circulating a cooling medium from the internal combustion engine to the heater;
The outlet of the oil cooler circulation passage and the outlet of the radiator bypass passage are connected to each other, and the cooling medium flow rate in the oil cooler circulation passage is provided at a portion that supplies the cooling medium downstream of the heater in the heater circulation passage. A three-way valve for simultaneously controlling the coolant flow rate in the radiator bypass passage;
A cooling device for an internal combustion engine, comprising:

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