JP5565283B2 - Cooling device for internal combustion engine - Google Patents

Description

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

  A cooling device for an internal combustion engine includes a cooling water flow path (water jacket) formed inside a cylinder block and a cylinder head of the internal combustion engine, a radiator as a heat exchanger, a water pump that pumps cooling water (refrigerant), and the like. The configuration is The cylinder block and the cylinder head are cooled by circulating water through the water jackets of the cylinder block and the cylinder head by a water pump.

  In such a cooling device for an internal combustion engine, it is preferable to control the flow rate of cooling water supplied to each water jacket of the cylinder block and the cylinder head in accordance with the operating state of the internal combustion engine. For example, in Patent Document 1, a water jacket of a cylinder head is divided into an intake side flow path and an exhaust side flow path, and the flow rate of each cooling water in the intake side flow path and the exhaust side flow path is controlled by a flow control valve. It has been shown. In the cooling apparatus for an internal combustion engine described in Patent Document 1, when the internal combustion engine is not in a low load operation state, the flow rate control valve is opened to increase the flow rate of the cooling water supplied to the exhaust side flow path.

JP 2009-191661 A

  However, in the cooling apparatus for an internal combustion engine described in Patent Document 1, when the internal combustion engine is not in a low load operation state, in other words, in a normal operation state and a high load operation state, the intake side of the cylinder head Cooling water is always circulated in both the flow path and the exhaust side flow path. For this reason, it is not possible to perform fine cooling water flow control according to the operating state of the internal combustion engine. Therefore, there is room for improvement in this respect.

  The present invention has been made in view of such problems, and provides a cooling device for an internal combustion engine capable of finely controlling the flow rate of cooling water according to the operating state of the internal combustion engine. Objective.

In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention relates to an internal combustion engine in which the flow rate of cooling water supplied to a water jacket provided in a cylinder block and the flow rate of cooling water supplied to a water jacket provided in a cylinder head are independently controlled. The water jacket of the cylinder head is divided into two flow paths, a main jacket and a sub jacket, which are respectively communicated with the downstream side of the water jacket of the cylinder block. A first electric water pump is disposed on the upstream side of the water jacket, and a second electric water pump is disposed on the downstream side of the sub jacket, which is upstream of the first electric water pump. A radiator is disposed downstream of the second electric water pump, and the internal combustion engine is operated. Depending on the state, the first, the operation control of the second electric water pump is performed independently, in the normal operating state of the internal combustion engine, the second electric water pump is stopped, only the first electric water pump In the high-load operation state of the internal combustion engine that is driven and has a higher load than the normal operation state, the first and second electric water pumps are both driven .

  According to the cooling apparatus for an internal combustion engine having the above-described configuration, the operation of the first and second electric water pumps is independently controlled, so that the water jacket and cylinder of the cylinder block can be used without using a flow control valve or a thermostat. The flow rate of the cooling water supplied to the main jacket and sub jacket of the head can be controlled according to the operating state of the internal combustion engine. As a result, it is possible to perform fine cooling water flow control according to the operating state of the internal combustion engine.

  According to the cooling apparatus for an internal combustion engine having the above configuration, in the normal operation state of the internal combustion engine, the second electric water pump provided on the downstream side of the sub jacket of the cylinder head is stopped. Become. For this reason, the cooling water from the water jacket of the cylinder block is easy to flow through the main jacket, but is difficult to flow through the sub jacket. On the other hand, in a high load operation state of the internal combustion engine, the cooling water from the water jacket of the cylinder block is supplied to the main jacket and the sub jacket of the cylinder head in accordance with the respective cross-sectional area ratios. Therefore, it is possible to perform fine cooling water flow control according to the operating state of the internal combustion engine. Moreover, in the normal operation state of the internal combustion engine, power consumption can be suppressed by stopping the second electric water pump.

  In the internal combustion engine cooling apparatus of the present invention, it is preferable that both the first and second electric water pumps are stopped while the internal combustion engine is warmed up.

  According to the cooling apparatus for an internal combustion engine having the above-described configuration, the flow of the cooling water is stopped in the water jacket of the cylinder block, the main jacket and the sub jacket of the cylinder head. Warm-up can be promoted and fuel consumption can be improved.

  In the cooling apparatus for an internal combustion engine of the present invention, the first electric water pump is stopped and only the second electric water pump is driven in a low load operation state of the internal combustion engine having a lower load than a normal operation state. preferable.

  According to the cooling apparatus for an internal combustion engine having the above-described configuration, the first electric water pump is stopped in the low-load operation state of the internal combustion engine, and thus the water flow resistance of the radiator, the first electric water pump, and the water jacket of the cylinder block. However, the water flow resistance of the main jacket and sub jacket of the cylinder head is significantly increased. For this reason, since cooling water hardly flows through the water jacket of the cylinder block, the temperature of the cylinder bore of the cylinder block can be kept high, and friction can be reduced to improve fuel efficiency. On the other hand, since the cooling water is circulated through the main jacket and sub jacket of the cylinder head by driving the second electric water pump, the cooling effect of the cylinder head is secured and the reliability of the internal combustion engine is secured. can do. Moreover, in a low load operation state of the internal combustion engine, power consumption can be suppressed by stopping the first electric water pump.

  According to the cooling apparatus for an internal combustion engine of the present invention, the operation of the first and second electric water pumps is independently controlled, so that the water jacket and cylinder of the cylinder block can be used without using a flow control valve or a thermostat. The flow rate of the cooling water supplied to the main jacket and sub jacket of the head can be controlled according to the operating state of the internal combustion engine. As a result, it is possible to perform fine cooling water flow control according to the operating state of the internal combustion engine.

1 is a block diagram showing a schematic configuration of a cooling device for an internal combustion engine according to an embodiment of the present invention. It is sectional drawing which shows an example of the water jacket of the cylinder block of an internal combustion engine, and the main jacket and sub jacket of a cylinder head. It is a figure which shows the flow of the cooling water in a cooling water circuit when a main electric water pump and a sub electric water pump are in warm-up mode. It is a figure which shows the flow of the cooling water in a cooling water circuit when a main electric water pump and a sub electric water pump are in fuel consumption mode. It is a figure which shows the flow of the cooling water in a cooling water circuit when a main electric water pump and a sub electric water pump are in cruise mode. It is a figure which shows the flow of the cooling water in a cooling water circuit when a main electric water pump and a sub electric water pump are in power mode.

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

  As shown in FIG. 1, the cooling device according to this embodiment is a cooling device applied to a vehicle on which an internal combustion engine 10 is mounted, and includes a radiator 30, a main electric water pump 31, a sub electric water pump 32, and These devices are provided with a cooling water circuit 100 that circulates cooling water (for example, LLC: Long Life Coolant).

  The internal combustion engine 10 is, for example, a gasoline engine, and includes a cylinder block 11 and a cylinder head 12 as shown in FIG. The cylinder block 11 and the cylinder head 12 are fastened by a head bolt via a head gasket (not shown). The internal combustion engine 10 may be a diesel engine or the like.

  The cylinder block 11 is provided with a plurality of cylinder bores 13 (only one is shown in FIG. 2) arranged in a line in the longitudinal direction. A piston 14 is inserted into the cylinder bore 13. The cylinder block 11 is formed with a water jacket 15 through which cooling water flows. The water jacket 15 is provided so as to surround the plurality of cylinder bores 13.

  The cylinder head 12 is provided with a combustion chamber 16 corresponding to the cylinder bore 13 of the cylinder block 11. A spark plug 17 is attached to the center of the top of the combustion chamber 16. An intake port 19 and an exhaust port 20 are connected to the combustion chamber 16. An intake valve 21 is provided between the intake port 19 and the combustion chamber 16, and the intake port 19 and the combustion chamber 16 are communicated or blocked by opening and closing the intake valve 21. Further, an exhaust valve 22 is provided between the exhaust port 20 and the combustion chamber 16, and the exhaust port 20 and the combustion chamber 16 are communicated or blocked by opening and closing the exhaust valve 22. The opening / closing drive of the intake valve 21 and the exhaust valve 22 is performed by rotation of an intake camshaft and an exhaust camshaft to which rotation of a crankshaft (not shown) is transmitted.

  The cylinder head 12 is formed with a water jacket through which cooling water flows. In this embodiment, the water jacket of the cylinder head 12 is divided into two cooling water passages of a main jacket 23 and a sub jacket 24. As illustrated in FIG. 2, the main jacket 23 is formed in a region around the spark plug 17, a region around the exhaust port 20, and a region around the exhaust valve 22. On the other hand, the sub jacket 24 is formed in a region below the intake port 19. The channel cross-sectional area of the main jacket 23 is larger than the channel cross-sectional area of the sub jacket 24. The main jacket 23 and the sub jacket 24 are communicated with the downstream side of the water jacket 15 of the cylinder block 11, respectively, and cooling water flows from the water jacket 15 of the cylinder block 11.

  Each of the main electric water pump 31 and the sub electric water pump 32 is an electric water pump capable of variably setting the discharge amount by controlling the rotation speed of the electric motor. The (maximum) discharge amount of the main electric water pump 31 is set larger than the (maximum) discharge amount of the sub electric water pump 32. Operation control of the main electric water pump 31 and the sub electric water pump 32 will be described later.

  As shown in FIG. 1, in the coolant circuit 100, the main electric water pump 31 is disposed on the upstream side of the water jacket 15 of the cylinder block 11. The sub electric water pump 32 is disposed on the downstream side of the sub jacket 24 of the cylinder head 12. A radiator 30 is disposed upstream of the main electric water pump 31 and downstream of the sub electric water pump 32. The main jacket 23 is connected to a passage 33 connecting the sub electric water pump 32 and the radiator 30 of the cooling water circuit 100. The flow of the cooling water in the cooling water circuit 100 will be described later.

  The ECU 200 includes a CPU, a ROM, a RAM, a backup RAM, and the like. The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU executes arithmetic processing based on various control programs and maps stored in the ROM. The RAM is a memory that temporarily stores calculation results in the CPU, data input from each sensor, and the like. The backup RAM is a non-volatile memory that stores data to be saved when the internal combustion engine 10 is stopped. It is.

  Various sensors that detect the operating state of the internal combustion engine 10 are connected to the ECU 200. For example, as various sensors, a water temperature sensor 41 that detects the temperature of cooling water of the cooling water circuit 100 (for example, cooling water of the main jacket 23 of the cylinder head 12), oil that lubricates and cools each part of the cylinder head 11 and the cylinder head 12. An oil temperature sensor 42 that detects the temperature (oil temperature) of the engine, an exhaust temperature sensor 43 that detects the temperature (exhaust temperature) of exhaust gas discharged to the exhaust system of the internal combustion engine 10, and the pressure (combustion pressure) in the combustion chamber 16 A combustion pressure sensor 44 for detecting the acceleration, an accelerator opening sensor 45 for detecting an operation amount (accelerator opening) of the accelerator pedal of the vehicle by the driver, and the like are provided.

  The ECU 200 executes various controls of the internal combustion engine 10 including throttle valve opening control, ignition timing control, fuel injection amount control, and the like based on output signals of various sensors. Further, the ECU 200 controls the flow of the cooling water in the cooling water circuit 100 by controlling the operation of the main electric water pump 31 and the sub electric water pump 32.

  In this embodiment, the operation control of the main electric water pump 31 and the sub electric water pump 32 is performed independently according to the operating state of the internal combustion engine 10. The flow rate of the cooling water supplied to the water jacket 15 of the cylinder block 11 and the main jacket 23 and the sub jacket 24 of the cylinder head 12 is independently controlled. Hereinafter, the operation control of the main electric water pump 31 and the sub electric water pump 32 will be specifically described.

  In this embodiment, as shown in FIGS. 3 to 6, the operation mode (operation mode) of the main electric water pump 31 and the sub electric water pump 32 is the warm-up mode, the fuel consumption mode, the cruise mode, and the power mode. One is provided.

  The warm-up mode is a mode that is set while the internal combustion engine 10 is warming up. Specifically, when the temperature Tw of the cooling water in the cooling water circuit 100 is lower than a preset threshold value T1 (Tw <T1), the main electric water pump 31 and the sub electric water pump 32 are set to the warm-up mode. Is done. Whether or not to set the warm-up mode can be determined based on the detection output of the water temperature sensor 41.

  On the other hand, the fuel consumption mode, the cruise mode, and the power mode are modes that are set during the warm period after the warm-up of the internal combustion engine 10 is completed. Specifically, when the temperature Tw of the cooling water in the cooling water circuit 100 is equal to or higher than the threshold value T1 (Tw ≧ T1), the operation mode of the main electric water pump 31 and the sub electric water pump 32 is the load X of the internal combustion engine 10. Accordingly, one of the fuel consumption mode, the cruise mode, and the power mode is set. This setting can be performed based on the detection output of the accelerator opening sensor 45.

  The fuel consumption mode is a mode that is set when the load X of the internal combustion engine 10 is extremely low to low, and is a mode that is set in a low load operation state of the internal combustion engine 10 that has a lower load than the normal operation state. . Specifically, when the load X of the internal combustion engine 10 is lower than a preset threshold value X1 (X <X1), the main electric water pump 31 and the sub electric water pump 32 are set to the fuel consumption mode.

  The cruise mode is a mode set when the load X of the internal combustion engine 10 is low to medium load. This cruise mode is a mode that is set in the normal operation state of the internal combustion engine 10, and is a mode that is set when the vehicle is in a steady running state. Specifically, when the load X of the internal combustion engine 10 is not less than the threshold value X1 and lower than the preset threshold value X2 (X1 ≦ X <X2), the main electric water pump 31 and the sub electric water pump 32 are in the cruise mode. Set to

  The power mode is a mode that is set when the load X of the internal combustion engine 10 is medium to high load, and is a mode that is set in a high load operation state of the internal combustion engine 10 that has a higher load than the normal operation state. Specifically, when the load X of the internal combustion engine 10 is equal to or greater than the threshold value X2 (X ≧ X2), the main electric water pump 31 and the sub electric water pump 32 are set to the power mode.

  Next, the flow of the cooling water in the cooling water circuit 100 in each operation mode described above will be described with reference to FIGS.

  As shown in FIG. 3, in the warm-up mode, both the main electric water pump 31 and the sub electric water pump 32 are stopped. At this time, the circulation of the cooling water is completely stopped in the water jacket 15 of the cylinder block 11, the main jacket 23 and the sub jacket 24 of the cylinder head 12. Thereby, when the internal combustion engine 10 is started at a low temperature, warm-up of the internal combustion engine 10 can be promoted to improve fuel efficiency.

  As shown in FIG. 4, in the fuel consumption mode, the main electric water pump 31 is stopped and only the sub electric water pump 32 is driven. At this time, the cooling water is circulated by driving the sub electric water pump 32 so as to circulate mainly through the main jacket 23 and the sub jacket 24 of the cylinder head 12 as indicated by solid arrows. On the other hand, the water flow resistance of the radiator 30, the main electric water pump 31, and the water jacket 15 of the cylinder block 11 is significantly larger than the water flow resistance of the main jacket 23 and the sub jacket 24 of the cylinder head 12. The cooling water is hardly circulated through the water jacket 15 of the cylinder block 11.

  Thereby, it is possible to promote the warm-up of the cylinder block 11 while ensuring the cooling effect of the cylinder head 12 in the low-load operation state of the internal combustion engine 10. Specifically, since the cooling water is hardly supplied to the water jacket 15 of the cylinder block 11, the temperature of the cylinder bore 13 can be kept high, and the friction can be reduced to improve the fuel efficiency. Further, the cooling water supplied to the main jacket 23 of the cylinder head 12 can suppress the area around the spark plug 17 of the cylinder head 12 and the area around the exhaust valve 22 from becoming high temperature. The reliability of the internal combustion engine 10 can be ensured. Further, power consumption can be suppressed by stopping the main electric water pump 31. Note that the discharge amount of the sub electric water pump 32 secures the amount of cooling water necessary for cooling the area around the ignition plug 17 of the cylinder head 12 and the area around the exhaust valve 22 in the fuel economy mode. The discharge amount is set to be able to be performed.

  As shown in FIG. 5, in the cruise mode, the sub electric water pump 32 is stopped and only the main electric water pump 31 is driven. At this time, the cooling water is circulated through the water jacket 15 of the cylinder block 11 by driving the main electric water pump 31. Here, in addition to the flow passage cross-sectional area of the main jacket 23 of the cylinder head 12 being made larger than the flow passage cross-sectional area of the sub jacket 24, the flow resistance caused by the sub electric water pump 32 being stopped is The cooling water from the water jacket 15 of the cylinder block 11 is easy to flow through the main jacket 23, but is difficult to flow through the sub jacket 24. Therefore, the cooling water is circulated mainly through the water jacket 15 of the cylinder block 11, the main jacket 23 of the cylinder head 12, and the radiator 30 as indicated by solid arrows. The cooling water is hardly circulated in the sub jacket 24 of the cylinder head 12.

  Thereby, power consumption can be suppressed by stopping the sub electric water pump 32 in the normal operation state of the internal combustion engine 10. In addition, at the minimum necessary flow rate only by the main electric water pump 31, the area around the cylinder bore 13 of the cylinder block 11, the spark plug 17 of the cylinder head 12, the area around the exhaust port 20, and the area around the exhaust valve 22. The region and the like can be prevented from becoming high temperature, and the reliability of the internal combustion engine 10 can be ensured. It should be noted that the discharge amount of the main electric water pump 31 is the range around the cylinder bore 13 of the cylinder block 11, the spark plug 17 of the cylinder head 12, the area around the exhaust port 20, and the exhaust valve 22 in the cruise mode. The discharge amount is set such that a cooling water amount necessary for cooling the surrounding area and the like can be secured.

  As shown in FIG. 6, in the power mode, the main electric water pump 31 and the sub electric water pump 32 are both driven. At this time, the cooling water is circulated through the water jacket 15 of the cylinder block 11 by driving the main electric water pump 31. Here, unlike the cruise mode shown in FIG. 5, the sub electric water pump 32 is driven, so that the cooling water is also distributed to the sub jacket 24. For this reason, the cooling water from the water jacket 15 of the cylinder block 11 is divided and distributed into the main jacket 23 and the sub jacket 24 of the cylinder head 12. In this case, the cooling water from the water jacket 15 of the cylinder block 11 is supplied to the main jacket 23 and the sub jacket 24 of the cylinder head 12 in accordance with the respective cross-sectional area ratios. As indicated by solid arrows, the first cooling water path that circulates through the water jacket 15 of the cylinder block 11, the main jacket 23 of the cylinder head 12, and the radiator 30, the water jacket 15 of the cylinder block 11, and the cylinder head. A second cooling water path that circulates the twelve sub jackets 24 and the radiator 30 is formed in the cooling water circuit 100.

  Thereby, in a high load operation state of the internal combustion engine 10, the area around the cylinder bore 13 of the cylinder block 11, the spark plug 17 of the cylinder head 12, the area around the exhaust port 20, the area around the exhaust valve 22, It can suppress that the area | region under the port 19 etc. become high temperature, and the reliability of the internal combustion engine 10 can be ensured.

  As described above, according to this embodiment, the operation of the main electric water pump 31 and the sub electric water pump 32 is independently controlled, so that the cylinder block 11 can be used without using a flow control valve or a thermostat. The flow rate of cooling water supplied to the water jacket 15, the main jacket 23 of the cylinder head 12, and the sub jacket 24 can be controlled according to the operating state of the internal combustion engine 10. For example, in the normal operation state of the internal combustion engine 10, the cruise mode is set, and the cooling water hardly flows through the sub jacket 24 compared to the main jacket 23 of the cylinder head 12. In the high load operation state, the power mode is set, and the cooling water is circulated through the main jacket 23 and the sub jacket 24 of the cylinder head 12. Therefore, it is possible to perform fine cooling water flow control according to the operating state of the internal combustion engine 10.

-Other embodiments-
The present invention is not limited only to the above-described embodiments, and all modifications and applications within the scope of the claims and within the scope equivalent to the scope are possible.

  The configurations of the main jacket 23 and the sub jacket 24 of the cylinder head 12 described in the above embodiment are merely examples (see FIG. 2), and the main jacket 23 and the sub jacket 24 may have other configurations. For example, the main jacket 23 is formed in a region around the ignition plug 17 of the cylinder head 12, a region around the exhaust port 20, and a region around the exhaust valve 22, and the sub jacket 24 is formed in the intake air of the cylinder head 12. It may be formed in a region around the port 19 and a region around the intake valve 21. Alternatively, the main jacket 23 is formed in a region around the ignition plug 17 of the cylinder head 12, a region around the exhaust port 20, and a region around the exhaust valve 22, and the sub jacket 24 bypasses the main jacket 23. You may form so that it may do.

  In the above embodiment, the operation mode of the main electric water pump 31 and the sub electric water pump 32 is switched according to the temperature of the cooling water and the load of the internal combustion engine 10, but the main electric water pump 31 and The operation mode of the sub electric water pump 32 may be switched.

  In the above embodiment, in the fuel consumption mode (see FIG. 4), the main electric water pump 31 is stopped so that the cooling water hardly flows through the radiator 30 and the water jacket 15 of the cylinder block 11. However, when the cooling water flowing to the water jacket 15 of the radiator 30 and the cylinder block 11 is more than necessary, the cooling water is supplied to the radiator 30 and the water jacket 15 of the cylinder block 11 by restricting the flow path using a solenoid valve or the like. May not be distributed.

  The present invention provides a cooling system for an internal combustion engine in which a flow rate of cooling water supplied to a water jacket provided in a cylinder block and a flow rate of cooling water supplied to a water jacket provided in a cylinder head are independently controlled. Available to the device.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 11 Cylinder block 12 Cylinder head 15 Water jacket 23 Main jacket 24 Sub jacket 30 Radiator 31 Main electric water pump (1st electric water pump)
32 Sub electric water pump (second electric water pump)
100 Cooling water circuit

Claims (3)

A cooling device for an internal combustion engine in which a flow rate of cooling water supplied to a water jacket provided in a cylinder block and a flow rate of cooling water supplied to a water jacket provided in a cylinder head are independently controlled. ,
The water jacket of the cylinder head is divided into two flow paths, a main jacket and a sub jacket, which are respectively communicated with the downstream side of the water jacket of the cylinder block.
A first electric water pump is disposed on the upstream side of the water jacket of the cylinder block, and a second electric water pump is disposed on the downstream side of the sub jacket.
A radiator is disposed upstream of the first electric water pump and downstream of the second electric water pump;
According to the operating state of the internal combustion engine, the operation control of the first and second electric water pumps is performed independently ,
In the normal operation state of the internal combustion engine, the second electric water pump is stopped, and only the first electric water pump is driven.
A cooling apparatus for an internal combustion engine, wherein the first and second electric water pumps are both driven in a high load operation state of the internal combustion engine having a higher load than a normal operation state . The cooling apparatus for an internal combustion engine according to claim 1 ,
The internal combustion engine cooling apparatus, wherein both the first and second electric water pumps are stopped during warm-up of the internal combustion engine. The cooling device for an internal combustion engine according to claim 1 or 2 ,
A cooling apparatus for an internal combustion engine, wherein the first electric water pump is stopped and only the second electric water pump is driven in a low load operation state of the internal combustion engine having a lower load than a normal operation state.

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