WO2013118410A1

WO2013118410A1 - Cooling device for internal combustion engine

Info

Publication number: WO2013118410A1
Application number: PCT/JP2012/083332
Authority: WO
Inventors: 宮下　茂樹; 大介中西
Original assignee: トヨタ自動車株式会社; 株式会社デンソー
Priority date: 2012-02-08
Filing date: 2012-12-21
Publication date: 2013-08-15
Also published as: JP5903917B2; CN104114828A; DE112012005840T5; CN104114828B; JP2013160195A; DE112012005840B4

Abstract

This cooling device (20) is used in an internal combustion engine (1) equipped with a turbocharger (15). The cooling device (20) has two independent cooling systems (21, 22) that cool the internal combustion engine (1) and have mutually different set temperatures. The low-temperature cooling system (22) includes a cooling circuit (30) that cools the intake port (10) of the cylinder head (7), the turbocharger (15), and the cylinder block (6), in this order.

Description

Cooling device for internal combustion engine

The present invention relates to a cooling device applied to an internal combustion engine with a turbocharger.

As a cooling device for an internal combustion engine, there is known a cooling system including a cooling system for flowing cooling water in order of an exhaust system of a cylinder head, a turbocharger, a radiator, and a cylinder block (Patent Document 1). In addition, Patent Documents 2 to 4 exist as prior art documents related to the present invention.

JP 2008-157102 A JP 59-224414 A JP 2001-152961 A JP 2001-107730 A

The cooling device of Patent Document 1 has good warm-up performance because the cooling water that has cooled the turbocharger is supplied to the water outlet of the cylinder block. However, since the cooling of the cylinder head intake system after warm-up is not sufficient, there is room for improvement in order to achieve both cooling performance and warm-up performance.

Therefore, an object of the present invention is to provide a cooling device for an internal combustion engine capable of achieving both cooling performance and warm-up performance.

The cooling device of the present invention is a cooling device for an internal combustion engine applied to an internal combustion engine with a turbocharger having a cylinder head to which an intake port is formed and a cylinder block to which the cylinder head is connected, to which a turbocharger is attached. Two cooling systems that cool the internal combustion engine and have different set temperatures and are independent from each other, and included in any one of the two cooling systems, the order of the intake port, the turbocharger, and the cylinder block And a cooling circuit for cooling them.

According to this cooling device, during normal operation after the completion of warm-up, the intake port is cooled by one cooling system and knocking of the internal combustion engine can be suppressed, and the other cooling system independent of this cooling system can Since the engine is cooled, the cooling performance during normal operation is high. When the internal combustion engine is warm before completion of warm-up, the heat taken from the turbocharger by the cooling of the turbocharger can be transferred to the cylinder block, so that the warm-up performance is improved. Therefore, both cooling performance and warm-up performance can be achieved.

In one aspect of the cooling device of the present invention, the one cooling system may have a lower set temperature than the other cooling system. According to this aspect, since the intake port can be cooled in a lower temperature region than other cooling systems, the cooling performance is further improved.

In one aspect of the cooling device of the present invention, the one cooling system may have a smaller flow rate of the refrigerant used for cooling than the other cooling system. In this case, the heat capacity of one cooling system is smaller than that of the other cooling system, and the temperature of the refrigerant is easily increased, so that the warm-up property is further improved.

In one aspect of the cooling device of the present invention, the internal combustion engine is provided with an intercooler for cooling the air supercharged to the turbocharger, and the cooling circuit is configured to cool the intake port before cooling it. The intercooler may be cooled. According to this aspect, since the intercooler is cooled before cooling the intake port having a high calorific value, it is easy to keep the intercooler at a low temperature.

In one aspect of the cooling device of the present invention, the internal combustion engine is a direct injection type internal combustion engine provided with an injector that directly injects fuel into a cylinder, and the cooling circuit is configured to cool the turbocharger. Alternatively, the injector may be cooled. During high-temperature operation of the internal combustion engine, the injector is heated and the fuel existing inside the injector is vaporized, so that fuel injection cannot be performed well, and the restartability of the internal combustion engine is deteriorated, for example. According to this aspect, when the injector is cooled, the fuel existing inside the injector can be prevented from being vaporized, so that the restartability can be prevented from deteriorating. Further, since the injector is cooled before the temperature of the refrigerant rises due to the cooling of the turbocharger, the coolability of the injector is high.

FIG. 1 is a diagram schematically showing an overall configuration of an internal combustion engine to which a cooling device according to a first embodiment is applied. FIG. 2 is a view schematically showing a part of the internal combustion engine of FIG. FIG. 3 is a diagram schematically showing the overall configuration of the internal combustion engine to which the cooling device according to the second embodiment is applied. FIG. 4 is a diagram schematically showing the overall configuration of the internal combustion engine to which the cooling device according to the third embodiment is applied. FIG. 5 is a view schematically showing a part of the internal combustion engine of FIG.

(First form)
As shown in FIGS. 1 and 2, the internal combustion engine 1 is configured as a reciprocating internal combustion engine in which a plurality (one in the figure) of cylinders 2 is provided, and a piston 3 is reciprocally provided in the cylinder 2. ing. The internal combustion engine 1 includes a cylinder block 6 in which each cylinder 2 is formed, and a cylinder head 7 connected to the cylinder block 6 so as to close an upper portion of each cylinder 2. An injector 8 is attached to the cylinder block 6 so that the tip end faces the cylinder 2. Therefore, the internal combustion engine 1 is configured as an in-cylinder direct injection internal combustion engine in which fuel is directly injected into the cylinder 2 by the injector 8.

The cylinder head 7 is formed with an intake port 10 through which air flows into the cylinder and an exhaust port 11 through which exhaust gas after combustion is discharged from the cylinder 2. The intake port 10 is opened and closed at a predetermined timing by an intake valve 13 and the exhaust port 11 is opened and closed by an exhaust valve 14, respectively. Although not shown, a spark plug for igniting the air-fuel mixture formed in the cylinder 2 is attached to the cylinder head 7. The internal combustion engine 1 is provided with a turbocharger 15 that supercharges intake air using exhaust energy, and the air compressed by the turbocharger 15 is taken into the cylinder 2 through the intake port 10 and burned. To be served. Further, an intercooler 16 for cooling the air supercharged by the turbocharger 15 is attached to the internal combustion engine 1.

As shown in FIG. 1, the internal combustion engine 1 is applied with a cooling device 20 for cooling each part thereof. The cooling device 20 includes two

cooling systems

21 and 22 that are independent of each other. The engine cooling system 21 mainly cools the periphery of the exhaust port 11 of the cylinder head 7. The engine cooling system 21 has a cooling circuit 23 that circulates coolant, which is a refrigerant, along a path indicated by a broken line. The cooling circuit 23 is provided with a heat exchanger 24 for exchanging heat between the cooled coolant and the outside air. The coolant exchanged by the heat exchanger 24 is pumped by a pump 25. The A refrigerant passage 26 is formed in the cylinder head 7 so as to surround the exhaust port 11, and the refrigerant passage 26 constitutes a part of the cooling circuit 23. A cooling circuit 30 downstream of the cylinder head 7 is connected to the heat exchanger 24. As shown in the drawing, the coolant circulates along the cooling circuit 23, so that the periphery of the exhaust port 11 of the cylinder head 7 is cooled.

The low-temperature cooling system 22 is set so that the set temperature is lower than that of the engine cooling system 21 described above, and the coolant flow rate is set to be lower than that of the engine cooling system 21. The low-temperature cooling system 22 includes a cooling circuit 30 indicated by a solid line, and the coolant circulates along the cooling circuit 30.

The cooling circuit 30 is provided with a heat exchanger 31 for exchanging heat between the cooled coolant and the outside air, and the coolant exchanged in the heat exchanger 31 is pumped by a pump 32. The cooling circuit 30 is branched into two on the downstream side of the pump 32, one branch path 30 a extends to the cylinder head 7 side, and the other branch path 30 b is connected to the intercooler 16. The branch passage 30 a extending toward the cylinder head 7 leads to a refrigerant passage 35 formed in the cylinder head 7 so as to surround the intake port 10, and the refrigerant passage 35 constitutes a part of the cooling circuit 30. When the coolant is guided to the refrigerant passage 35, the intake port 10 is cooled. The cooling circuit 30 is connected to the turbocharger 15 through the refrigerant passage 35, and the coolant is guided to a passage (not shown) formed inside the turbocharger 15 to cool each part of the turbocharger 15.

As shown in FIG. 1, the cooling circuit 30 downstream of the turbocharger 15 is connected to a water jacket 36 formed in the cylinder block 6. As is well known, the water jacket 36 is a passage extending so as to surround each cylinder 2. On the downstream side of the water jacket 36, the other branch passage 30b that has cooled the intercooler 16 is joined. The cooling circuit 30 is connected to the heat exchanger 31 downstream of the joining position. In this way, the cooling circuit 30 included in the low-temperature cooling system 22 cools the intake port 10, the turbocharger 15, and the cylinder block 6 in this order.

Since the cooling device 20 has the above-described configuration, during normal operation after the warm-up of the internal combustion engine 1 is completed, the intake port 10 is cooled by the low-temperature cooling system 22 and knocking of the internal combustion engine 1 can be suppressed. Since the internal combustion engine 1 is cooled by the independent engine cooling system 21, the cooling performance during normal operation is high. When the internal combustion engine 1 is cold before the warm-up is completed, the heat deprived from the turbocharger 15 by the cooling of the turbocharger 15 can be transferred to the cylinder block 6, so that the warm-up property is improved. Therefore, the cooling device 20 can achieve both cooling performance and warm-up performance.

Further, since the set temperature of the low-temperature cooling system 22 is lower than that of the engine cooling system 21, the low-temperature cooling system 22 can cool the intake port 10 in a lower temperature region than the engine cooling system 21, so that the cooling performance is further improved. Moreover, since the coolant flow used for cooling in the low-temperature cooling system 22 is smaller than that in the engine cooling system 21, the heat capacity of the low-temperature cooling system 22 is smaller than that in the engine cooling system 21. Accordingly, the temperature of the coolant of the low-temperature cooling system 22 is easily raised, so that the warm-up property is further improved. In this embodiment, the low-temperature cooling system 22 corresponds to one cooling system according to the present invention, and the engine cooling system 21 corresponds to another cooling system according to the present invention.

(Second form)
Next, a second embodiment of the present invention will be described with reference to FIG. Since the second form is common to the first form except for some forms of the cooling device, the same reference numerals are assigned to the common members in the drawings, and the description is omitted. The cooling device 40 according to the second embodiment has two

cooling systems

41 and 42 that are independent of each other. The engine cooling system 41 has the same configuration as the cooling system 21 of the first embodiment. The low-temperature cooling system 42 is set so that the set temperature is lower than that of the engine cooling system 41 and the coolant flow rate is reduced. The low-temperature cooling system 42 includes a cooling circuit 45, and the cooling circuit 45 is provided with a heat exchanger 46 and a pump 47. Unlike the first embodiment, the cooling circuit 45 downstream of the pump 47 is connected to the intercooler 16 without branching. Therefore, the cooling circuit 45 cools the intercooler 16 before cooling the intake port 10.

According to the second mode, similar to the first mode, since the cooling is performed in the order of the intake port 10, the turbocharger 15, and the cylinder block 6, the same effect as the first mode can be obtained. Furthermore, according to the second embodiment, since the intercooler 16 is cooled before the intake port 10 having a high calorific value is cooled, it is easy to keep the intercooler 16 at a low temperature. In this embodiment, the low-temperature cooling system 42 corresponds to one cooling system according to the present invention, and the engine cooling system 41 corresponds to the other cooling system according to the present invention.

(Third form)
Next, a third embodiment of the present invention will be described with reference to FIGS. Since the third form is common to the first form except for some forms of the cooling device, common members are denoted by the same reference numerals in the drawings, and description thereof is omitted. The cooling device 50 according to the third embodiment has two

cooling systems

51 and 52 that are independent of each other. The engine cooling system 51 has the same configuration as the cooling system 21 of the first embodiment. The low-temperature cooling system 52 is set so that the set temperature is lower than that of the engine cooling system 51 and the coolant flow rate is reduced. The low-temperature cooling system 52 includes a cooling circuit 55, and the cooling circuit 55 is provided with a heat exchanger 56 and a pump 57. The cooling circuit 55 branches into two downstream of the pump 57, one branch passage 55 a extends to the cylinder head 7 side, and the other branch passage 55 b is connected to the intercooler 16. A refrigerant passage 58 is formed in the cylinder head 7 so as to surround the intake port 10, and the refrigerant passage 58 is connected to a refrigerant passage 59 formed in the cylinder block 6 so as to surround the injector 8. Each

refrigerant passage

58 and 59 constitutes a part of the cooling circuit 55. Therefore, the coolant guided to the cylinder head 7 is guided to the periphery of the intake port 10 and the injector 8 through the

refrigerant passages

58 and 59 as shown by arrows in FIG. It is burned. That is, the cooling circuit 55 cools the injector 8 before cooling the turbocharger 15.

According to the third embodiment, the same effect as in the first embodiment can be obtained because the intake port 10, the turbocharger 15, and the cylinder block 6 are cooled in the same order as in the first embodiment. Furthermore, according to the third embodiment, since the injector 8 is cooled to prevent the fuel existing in the injector 8 from being vaporized, the fuel injection is not successfully performed by the vaporization, and the restartability of the internal combustion engine 1 can be prevented. Can prevent the situation from getting worse. Further, since the injector 8 is cooled before the temperature of the coolant rises due to the cooling of the turbocharger 15, the coolability of the injector 8 is high. In this embodiment, the low-temperature cooling system 52 corresponds to one cooling system according to the present invention, and the engine cooling system 51 corresponds to the other cooling system according to the present invention.

The present invention is not limited to the above embodiment, and can be implemented in various forms within the scope of the gist of the present invention. In each of the above embodiments, an in-cylinder direct injection internal combustion engine is exemplified as the internal combustion engine to which the cooling device is applied. However, the cooling device of the present invention may be applied to any type of internal combustion engine. For example, the present invention can be applied to a port injection type internal combustion engine in which an injector is provided at an intake port, and the present invention can also be applied to an internal combustion engine such as a self-ignition type diesel engine that does not require a spark plug.

Claims

In a cooling device for an internal combustion engine applied to an internal combustion engine with a turbocharger, which includes a cylinder head in which an intake port is formed, and a cylinder block to which the cylinder head is connected, to which a turbocharger is attached.
Two cooling systems for cooling the internal combustion engine and having different set temperatures and independent from each other;
A cooling circuit that is included in one of the two cooling systems and cools the intake port, the turbocharger, and the cylinder block in this order;
A cooling device for an internal combustion engine.
The cooling apparatus according to claim 1, wherein the one cooling system has a lower set temperature than either one of the two cooling systems.
The cooling device according to claim 1 or 2, wherein the one cooling system has a smaller flow rate of the refrigerant used for cooling than the other cooling system of the two cooling systems.
The internal combustion engine is provided with an intercooler for cooling the air supercharged to the turbocharger,
The cooling device according to any one of claims 1 to 3, wherein the cooling circuit cools the intercooler before cooling the intake port.
The internal combustion engine is an in-cylinder direct injection internal combustion engine provided with an injector that directly injects fuel into a cylinder.
The cooling device according to any one of claims 1 to 4, wherein the cooling circuit cools the injector before cooling the turbocharger.