JP5040816B2 - Internal combustion engine cooling circuit - Google Patents

Description

  The present invention relates to a cooling system for an internal combustion engine, and more specifically to a cooling circuit for an internal combustion engine capable of efficiently warming up and heating / cooling the internal combustion engine and a transmission.

  An internal combustion engine (engine) mounted on a vehicle includes a cooling circuit that circulates generated heat by circulating cooling water using a pump or the like. This cooling circuit is configured such that the temperature of the cooling water is lowered by heating the cooling water by the internal combustion engine and exchanging heat with the atmosphere by the radiator. The cooling circuit of the internal combustion engine is communicated with the transmission, and the hydraulic fluid of the transmission is heated to an appropriate temperature by the heated cooling water. Some transmissions are provided with a cooling path in addition to the cooling water circuit of the internal combustion engine in order to prevent overheating of the hydraulic fluid of the transmission.

In such an internal combustion engine, the ideal engine temperature differs between the cylinder block and the cylinder head. On the other hand, a two-system cooling device for an internal combustion engine (see Patent Document 1) that includes a cylinder block side cooling system and a cylinder head side cooling system independently is disclosed.
(See Patent Document 1).
JP 63-259117 A

  In the configuration described in Patent Document 1, the heat generated by the internal combustion engine is consumed by the heat exchanger of the transmission, so that there is a problem that it takes time to warm up. In addition, although the ideal engine temperature differs between the internal combustion engine and the transmission, both of them are controlled to the same temperature by cooling water, so that there is a problem that the internal combustion engine and the transmission cannot always exhibit sufficient performance. .

  In addition, since the transmission has little self-heating and only exchanges heat with the oil warmer (oil cooler) by the cooling water, the hydraulic oil is difficult to warm up during warm-up, and the friction of the sliding part does not become low, resulting in lower torque transmission efficiency. There was also a problem that fuel consumption deteriorated.

  The present invention has been made paying attention to such a conventional problem, and it is possible to efficiently warm up the internal combustion engine and the transmission, and to cool the internal combustion engine that can efficiently raise and cool the temperature during operation. An object is to provide a circuit.

According to one embodiment of the present invention, a first cooling water path for circulating cooling water to a cylinder head of an internal combustion engine, a second cooling water path for circulating cooling water to a cylinder block of the internal combustion engine, and an internal combustion engine First temperature measuring means for measuring the temperature of the cylinder head, second temperature measuring means for measuring the temperature of the cylinder block of the internal combustion engine, and third temperature measuring means for measuring the temperature of the hydraulic fluid of the transmission And a switching valve that circulates the cooling water in at least one of the first and second cooling water paths, and the switching control of the switching valve based on the measurement results of the first, second, and third temperature measuring means, Control means for controlling the opening degree of the thermostat, and when the temperature measured by the first temperature measurement means is less than the first predetermined value, the control means sets the switching valve to the second cooling Distribute only to the water channel When the temperature measured by the first temperature measuring means is equal to or higher than the first predetermined value, the switching control is performed so that the switching valve is circulated only in the first cooling water path, and the second When the temperature measured by the temperature measuring means is equal to or higher than the second predetermined value, the switching valve is controlled to flow through the first and second cooling water paths, and is measured by the third temperature measuring means. When the temperature is equal to or higher than the third predetermined value, the switching valve is controlled to be switched so as to flow through the first and second cooling water paths .

  According to the present invention, since the switching valve is controlled based on the temperature of the cylinder head, the temperature of the cylinder block, and the hydraulic oil temperature of the transmission, these temperatures can be controlled independently. The warm-up of the cylinder block and the transmission can be accelerated, and fuel efficiency, torque transmission efficiency, machine life, etc. can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a cooling circuit 1 for an internal combustion engine according to an embodiment of the present invention.

  The cooling circuit 1 includes an internal combustion engine (engine) 10, a heat exchanger 21 that exchanges heat between the hydraulic oil of the transmission 20 and cooling water, and a radiator 30 that exchanges heat between the atmosphere and cooling water. This is constituted by a cooling water passage 40 through which the cooling water circulates.

  This cooling water path 40 controls the communication of the cooling water path to the radiator 30 side with the pump 50 that circulates the cooling water and distributes the cooling water only to the bypass path 41 or distributes the cooling water also to the radiator 30. And a thermostat 60 for switching whether or not to perform at a predetermined temperature.

  Further, in the engine 10, the cooling water passage 40 circulates the cooling water through the cylinder head side passage (first cooling water passage) 42 through which the cooling water flows through the water jacket of the cylinder head 11 and the water jacket of the cylinder block 12. And a cylinder block side path (second cooling water path) 43 to be made. A switching valve 70 is provided that communicates with one of the cylinder head side path 42 and the cylinder block side path 43 and allows the coolant to flow therethrough.

  The cylinder head 11 has a temperature sensor (first temperature sensor) 11a that measures the temperature of the cylinder head 11, and the cylinder block 12 has a temperature sensor (second temperature sensor) 12a that measures the temperature of the cylinder block 12. Each is provided.

  Further, the heat exchanger 21 is provided with a temperature sensor (third temperature sensor) 21 a that measures the hydraulic oil temperature of the transmission 20 in the heat exchanger 21.

  The control device 100 controls the switching of the thermostat 60 in addition to controlling the switching of the switching valve 70 based on the temperatures measured by these temperature sensors 11a, 12a and 21a.

  The cooling water circulated by the pump 50 flows through at least one of the cylinder head side path 42 and the cylinder block side path 43 of the engine 10. The switching valve 70 is constituted by, for example, a three-way valve, and switches the coolant to at least one (or both) of the cylinder head side path 42 and the cylinder block side path 43 so that the flow path is possible.

  In the cylinder block side path 43, the cooling water is overheated by the combustion of the cylinder block 12, and the cylinder block 12 is warmed up and cooled by the cooling water. Further, in the cylinder head side path 42, the cylinder head 11 is warmed up and cooled by the cooling water.

  The cooling water that has passed through the switching valve 70 is warmed up and cooled by the cooling water in the heat exchanger 21.

  The cooling water passing through the engine 10 and the transmission 20 is cooled by heat exchange with the atmosphere by the radiator 30. When the cooling water temperature is equal to or lower than the predetermined temperature, the thermostat 60 is controlled to be switched, canceling the route to the radiator 30 and allowing only the bypass route 41 to flow, thereby promoting warm-up of the engine 10.

  The cooling water that has passed through the thermostat 60 is circulated in the cooling water passage 40 by the pump 50 again.

  The thermostat 60 uses a so-called electric thermostat configured so that the flow rate can be controlled by changing the opening degree. The control device 100 controls the valve opening degree of the thermostat 60 so that the cooling water temperature becomes the target temperature based on a preset cooling water target temperature (for example, 90 [° C.]). For example, when the cooling water temperature is higher than the target temperature, the valve opening is increased to reduce the cooling water flow rate to the radiator 30. Further, when the cooling water temperature is lower than the target temperature, the valve opening degree is decreased and the cooling water flow rate to the radiator 30 is increased.

  Next, the operation of the cooling circuit 1 configured as described above will be described.

  In the cooling circuit 1 of the present invention, the control device 100 has a switching valve 70 and a control valve 100 based on the temperature of the cylinder head 11, the temperature of the cylinder block 12, and the temperature of the hydraulic oil in the heat exchanger 21 of the transmission 20. The thermostat 60 is controlled. Thereby, the cooling water heated by the engine 10 warms up the transmission 20 in the heat exchanger 21. Further, after warming up, the radiator 30 cools the air by exchanging heat with the air of the cooling water, and the cooled cooling water cools the transmission 20 in the heat exchanger 21.

  More specifically, the following processing is executed.

  First, the control device 100 determines whether or not the temperature of the cylinder head 11 has become equal to or higher than a predetermined temperature T1 [° C.], and executes the following processing (processing A).

  When the temperature of the cylinder head 11 is less than the predetermined temperature T1 [° C.], the control device 100 controls the switching of the switching valve 70, shuts off the cylinder head side path 42, and does not allow the coolant to flow in. It is assumed that the cooling water flows only in the side path 43.

  In this state, as shown in FIG. 2, in the engine 10, the coolant flows through only the cylinder block 12 that is heated most. In this state, the thermostat 60 is controlled to the bypass path 41 side. Accordingly, the cooling water circulates only through the cylinder block side path 43 and the heat exchanger 21, thereby promoting warming up of the engine 10 and the transmission 20.

  On the other hand, when the temperature of the cylinder head 11 becomes equal to or higher than the predetermined temperature T1 [° C.], the control device 100 controls the switching of the switching valve 70 so that the coolant flows through the cylinder head side path 42 and the cylinder block side The path 43 is blocked so that the cooling water does not flow.

  In this state, as shown in FIG. 3, in the engine 10, the flow of the cooling water in the cylinder block 12 is interrupted, and the cooling water flows only in the cylinder head 11. Therefore, the cooling water in the cylinder block side path 43 does not circulate, so the engine 10 can be warmed up more quickly. Moreover, since the temperature of the cooling water is already equal to or higher than the above-described T1 [° C.], the cylinder head 11 and the transmission 20 are kept warm.

  Here, when the cooling water does not circulate in the cylinder block 12, the temperature of the cylinder block 12 increases rapidly. Therefore, the control device 100 determines whether or not the temperature of the cylinder block 12 has become equal to or higher than a predetermined temperature T2 [° C.], and executes the following process (process B). Note that T2> T1.

  When the temperature of the cylinder head 11 is less than the predetermined temperature T2 [° C.], the control device 100 controls the switching valve 70 so that the cooling water flows through the cylinder head side path 42 and the cylinder block side path 43 is changed. The state is shut off so that the cooling water does not flow (the state shown in FIG. 3 described above).

  On the other hand, when the temperature of the cylinder head 11 becomes equal to or higher than the predetermined temperature T2 [° C.], the control device 100 controls the switching valve 70 to switch both the cylinder head side path 42 and the cylinder block side path 43. It is assumed that the cooling water flows through

  In this state, as shown in FIG. 4, in the engine 10, the coolant flows through the cylinder head side path 42 and the cylinder block side path 43. Therefore, the cooling water heated by the cylinder block 12 circulates through the heat exchanger 21 and the cylinder block 12 to warm up, and circulates through the cylinder block side path 43 to suppress overheating of the cylinder block 12.

  Further, the control device 100 determines whether or not the temperature of the heat exchanger 21 of the transmission 20 is equal to or higher than T3 [° C.], and executes the following processing (processing C). Note that T3> T1.

  When the temperature of the heat exchanger 21 is less than T3 [° C.], the control device 100 controls the switching valve 70 so that the cooling water flows in the cylinder head side path 42 and cools in the cylinder block side path 43. It is set as the state which water does not flow in (state of above-mentioned FIG. 2).

  When the temperature of the heat exchanger 21 becomes equal to or higher than the predetermined temperature T3 [° C.], the control device 100 switches and controls the switching valve 70 to both the cylinder head side path 42 and the cylinder block side path 43. It is assumed that the cooling water flows through

  The process C is executed in parallel with the process A and the process B described above. That is, when the temperature of the cylinder head 11 becomes T1 [° C.] or more and when the temperature of the cylinder block 12 becomes T2 [° C.] or more, or the temperature of the heat exchanger 21 becomes T3 [° C. When the above is reached, the control device 100 sets the cooling water to flow through both the cylinder head side path 42 and the cylinder block side path 43.

  In this state, the cooling water flows through the cylinder head 11 and the cylinder block 12 in the engine 10 as in FIG. Accordingly, the cooling water heated by the cylinder block 12 circulates through the heat exchanger 21 and the cylinder block 12 to warm up, and circulates through the cylinder block 12 to cool the cylinder block 12.

  Further, the control device 100 is configured such that when the temperature of the cylinder head 11 becomes equal to or higher than the predetermined temperature T1 [° C.], when the temperature of the cylinder block 12 becomes equal to or higher than the predetermined temperature T2 [° C.], or When the temperature is equal to or higher than the predetermined temperature T3 [° C.], the thermostat 60 is controlled to be switched so that the cooling water flows to the radiator 30 side (Process D).

  In this state, the cooling water circulates in the radiator 30 as shown in FIG. As a result, heat is exchanged between the cooling water and the atmosphere in the radiator 30, so that the cooling water temperature is lowered and the temperature rise of the cylinder head 11, the cylinder block 12 and the transmission 20 of the engine 10 can be suppressed.

  Note that the process D is executed in parallel with the process A, the process B, and the process C described above. That is, in parallel with the process for controlling the switching of the thermostat 60, the switching valve 70 is controlled to be switched in the processes A, B and C described above.

  For example, when the cooling water temperature becomes T2 [° C.] or less as a result of the circulation of the cooling water to the radiator 30 by switching the thermostat 60, the engine 10 enters a supercooled state. 100 controls the switching valve 70 to flow the cooling water through the cylinder head side path 42 so that the cooling water does not flow into the cylinder block side path 43. Thereby, overcooling on the cylinder block 12 side can be prevented, and deterioration of friction loss can be suppressed. Further, in the cylinder head 11, since the cooling is promoted, knocking can be suppressed. At this time, if the cooling water temperature exceeds T1 [° C.], the thermostat 60 does not switch to the bypass path 41 side.

  Thus, when the cooling water temperature rises and the thermostat 60 switches to the radiator 30 side, even if the cooling water temperature suddenly drops, the fuel consumption and generated torque of the engine are not reduced. Be controlled.

  In the above-described control, T1, T2, and T3 [° C.] are set as threshold values for switching control, but hysteresis may be set to suppress control hunting.

  As described above, the cooling circuit 1 for an internal combustion engine according to the embodiment of the present invention switches and controls the switching valve 70 based on the temperatures of the cylinder head 11, the cylinder block 12, and the transmission 20 of the engine. More specifically, it is controlled whether or not cooling water is allowed to flow through the cylinder head 11 based on the temperature of the cylinder head 11, and whether or not cooling water is allowed to flow through the cylinder block 12 based on the temperature of the cylinder block 12. And whether or not the coolant is allowed to flow through the cylinder block 12 based on the temperature of the transmission 20 is controlled. Further, when the thermostat 60 is opened on the radiator 30 side, the opening degree of the thermostat 60 is controlled to control the temperature of the circulating cooling water.

  By controlling in this way, the temperature of the cylinder head 11 of the engine 10, the temperature of the cylinder block 12, and the temperature of the transmission 20 can be individually controlled. For example, the cylinder block 12 has the best fuel efficiency at a predetermined temperature (for example, 90 ° C. or higher), but the cylinder head 11 can be prevented from knocking by setting the temperature to the predetermined temperature or lower. Further, by setting the transmission 20 to a predetermined temperature or less, functional reliability such as wear prevention can be improved.

  In this way, by controlling the temperatures of the cylinder head 11, the cylinder block 12, and the transmission, respectively, the engine can be warmed up efficiently at the time of engine start, fuel efficiency can be improved, friction loss and knock can be reduced, and the engine 10 Output transmission efficiency increases.

It is explanatory drawing of the cooling circuit of the internal combustion engine of 1st Example of this invention. It is explanatory drawing of the process A of the cooling circuit of the internal combustion engine of 1st Example of this invention. It is explanatory drawing of the process B of the cooling circuit of the internal combustion engine of 1st Example of this invention. It is explanatory drawing of the process C of the cooling circuit of the internal combustion engine of 1st Example of this invention. It is explanatory drawing of the process D of the cooling circuit of the internal combustion engine of 1st Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling circuit 10 Engine 11 Cylinder head 11a Temperature sensor 12 Cylinder block 12a Temperature sensor 20 Transmission 21 Heat exchanger 21a Temperature sensor 30 Radiator 40 Cooling water path 41 Bypass path 42 Cylinder head side path 43 Cylinder block side path 50 Pump 60 Thermostat 70 switching valve 100 control device

Claims (3)

In a cooling circuit for an internal combustion engine in which cooling water is circulated by a pump between the internal combustion engine, a transmission, and a radiator,
A thermostat configured to be able to adjust the flow rate of the cooling water passing through the opening, and capable of switching to the bypass path by blocking the path to the radiator;
A first cooling water path for circulating cooling water to a cylinder head of the internal combustion engine;
A second cooling water path for circulating cooling water to a cylinder block of the internal combustion engine;
First temperature measuring means for measuring the temperature of the cylinder head of the internal combustion engine;
Second temperature measuring means for measuring the temperature of the cylinder block of the internal combustion engine;
Third temperature measuring means for measuring the temperature of hydraulic oil of the transmission;
A switching valve for circulating cooling water in at least one of the first and second cooling water paths;
Based on the measurement results of the first, second and third temperature measuring means, the switching valve is controlled to switch, and the control means for controlling the opening of the thermostat;
Equipped with a,
The control means includes
When the temperature measured by the first temperature measuring means is less than a first predetermined value, the switching valve is controlled to flow only in the second cooling water path,
When the temperature measured by the first temperature measuring means is equal to or higher than a first predetermined value, the switching valve is controlled to flow only through the first cooling water path,
If the temperature measured by the second temperature measuring means is equal to or higher than a second predetermined value, the switching valve is controlled to flow through the first and second cooling water paths,
When the temperature measured by the third temperature measuring means is equal to or higher than a third predetermined value, the switching valve is controlled to flow through the first and second cooling water paths. > A cooling circuit for an internal combustion engine. When the temperature measured by the first temperature measuring means is equal to or higher than a first predetermined value, the temperature measured by the second temperature measuring means is equal to or higher than a second predetermined value. Alternatively, when the temperature measured by the third temperature measuring means is equal to or higher than a third predetermined value, the thermostat is switched and controlled so that cooling water flows to the radiator. A cooling circuit for an internal combustion engine according to claim 1 . The control means, after switching the thermostat so as to circulate the cooling water to the radiator, controls the opening of the thermostat so that the cooling water reaches a target temperature, and the flow rate of the cooling water to the radiator The cooling circuit for the internal combustion engine according to claim 1 or 2, wherein

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