JPH07119463A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE:To keep the temperature of cooling water at a proper value and to stabilize running of an internal combustion engine by a method wherein when a cooling water temperature attains a set temperature, low temperature cooling water through a low temperature confluence water passage and high temperature cooling water from an upper stream water passage are mixed together by a temperature regulating valve. CONSTITUTION:The temperature of cooling water is maintained at a proper value so that operation of an engine 1 is stabilized. In which case, when a water temperature is below a set temperature, a total amount of cooling water fed with a pressure with the aid of a water pump 2 is circulated through a high temperature cooling water circuit consisting of a number of water passages 100-103 containing a temperature regulating valve 4. Meanwhile, a low temperature cooling water circuit consisting of a number of water passages 200-205, 301, 303, and 304 causes circulation of a total amount of cooling water, fed with a pressure with the aid of a different water pump 3, through an air cooler 11, a lubricating oil cooler 12, and a heat-exchanger 21. When a water temperature attains a set temperature, low temperature cooling water through a low temperature confluence water passage 302 and high temperature cooling water through an upper stream water passage 103 are mixed together by a temperature regulating valve 4 to regulate temperature into a proper value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a water-cooled internal combustion engine equipped with a supercharger.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a first conventional example of a cooling device for a water-cooled internal combustion engine equipped with a supercharger. The configuration and operation will be described with reference to FIG. In the figure, 1
Is an engine, 2 and 3 are water pumps, 6 is a directional control valve for cooling water, 11 is an air cooler for supercharging, 12 is a lubricating oil cooler, 21 and 22 are heat exchangers, 100 to 105,200.
˜206 are cooling water passages, 111˜112 are supercharging air passages, 121˜122 are lubricating oil passages, and 401˜40.
3 is a passage for the secondary side cooling water for the heat exchanger.

In this configuration, the cooling water path is divided into a system for supplying cooling water to the water jacket of the cylinder and the cylinder head of the engine 1 and a system for supplying cooling water to the air cooler 11 and the lubricating oil cooler 12. The cooling water supplied to the water jacket is supplied to the heat exchanger 21 through the water passages 402 to 403.
The cooling water that is cooled by heat exchange with the secondary cooling water flowing to the air cooling device 11 and the cooling water supplied to the air cooling device is exchanged with the secondary cooling water flowing from the water passages 401 to 402 in the heat exchanger 22. Cooling by heat exchange. The passage 102 of the cooling water leading from the outlet side of the water jacket to the heat exchanger 21
A three-port directional control valve 6 is provided between No. 103 and No. 103. When the temperature of the cooling water is low, the valve on the side of the flow path 103 is closed and the valve on the side of the flow path 104 is opened, so that the cooling water flows through the heat exchanger 2
1 is circulated from the flow passage 104 to the water jacket via the water pump 2 without passing through 1, and when the cooling water temperature rises moderately, the valve on the flow passage 104 side is closed and the valve on the flow passage 103 side is opened. Then, the cooling water is cooled by heat exchange in the heat exchanger 21.

Although this configuration requires two heat exchangers,
If the capacity setting of the heat exchanger is suitable, the temperature control of the cooling device can be performed in a state that can be substantially satisfied. Also,
When good quality water can be supplied as the secondary side cooling water, the heat exchanger 22 is omitted, the secondary side cooling water is supplied from the water passage 200, and the secondary side cooling water is sent via the water passages 201 to 206. It is also possible to short-circuit the cooling water passage 402 on the secondary side.

FIG. 4 is a block diagram of a second conventional example of a cooling device for a water-cooled internal combustion engine equipped with a supercharger. The symbols and names of the respective elements shown in the figure are cooling water passages 301 and 302. Other than that is the same as the case of the first conventional example shown in FIG. The heat exchanger consists of one unit, and the heat of the cooling water in the water jacket around the cylinder and the heat recovered by the air cooler 11 and the lubricating oil cooler 12 are all radiated by the heat exchanger 21. It is a method.

[0006]

The requirement for improving the performance of an internal combustion engine is to reduce the supply air temperature as much as possible. The reduction of the supply air temperature increases the density of the air filling the cylinder, and the mass of the air involved in the combustion increases, so that the improvement of the combustion and the increase of the output can be achieved at the same time. Generally, when the engine operates under high load, the upper limit of the combustion gas temperature is a condition that restricts the continuation of operation.However, if the supply air temperature is reduced, the combustion gas temperature can be lowered, and the engine can be operated under high load. Continuous operation of
The effect of suppressing the generation of NO _x is also obtained.

The object of the present invention is to maintain an appropriate cooling water temperature with a simple structure and to achieve both improved engine output and improved combustion, and stable cooling performance even during continuous operation under high load. It is to provide a cooling device for an internal combustion engine that can maintain the above.

[0008]

A cooling device for an internal combustion engine according to the present invention is a water-cooled internal combustion engine equipped with a supercharger; the water pump 2 and the opening / closing of a valve opening and the cooling water linked to the temperature of the cooling water. High temperature system cooling constituted by a temperature control valve 4 capable of controlling a flow rate, and water passages 100 to 103 for communicating a closed circuit between the water pump, a water jacket around the cylinder of the engine 1 and the temperature control valve. Water circuit; water pump 3, air cooler 11 for supercharging, lubricating oil cooler 12, heat exchanger 21, and water passage 20 that communicates with each other in a closed circuit.
0-205, 301, 303, 304; a low temperature system cooling water circuit; an upstream part of the heat exchanger 21 in the low temperature system cooling water circuit from an upstream part of the temperature control valve 4 in the high temperature system cooling water circuit. A high temperature confluent water passage 104 into which a part of the high temperature system cooling water flows, and a low temperature into which a part of the low temperature system cooling water flows from the upstream part of the heat exchanger to the low temperature side cooling water inlet of the temperature control valve. It is characterized by having a confluent water passage 302.

[0009]

In order to maintain a stable operating condition of the engine, it is necessary that the temperature of the cooling water be kept constant at an appropriate set temperature. After the engine is started in the cold state, the water temperature in the water jacket around the cylinder gradually rises, but if the water temperature is below the set temperature, the entire amount of the cooling water sent to the water jacket by the water pump 2 is the high temperature in the closed circuit. The cooling water temperature rises as it circulates in the system cooling water circuit. In the meantime, in the low temperature system cooling water circuit, the entire amount of the cooling water pumped by the pump 3 is supplied to the air cooler 1.
1, the lubricating oil cooler 12, and the heat exchanger 21 circulate.

When the cooling water temperature reaches the set temperature, the low temperature converging water passage 302 is connected to the temperature adjusting valve 4 so as to maintain the cooling water temperature.
A part of the cooling water of the low temperature system is caused to flow into the temperature control valve 4, and the cooling water of the high temperature system flowing from the upstream side water passage 103 is merged and mixed in the water passage 100 on the downstream side of the valve. At this time, the cooling water temperature of the water passage is detected by a temperature detector provided in the water passage 100, and the openings of the high temperature system cooling water throttle and the low temperature system cooling water throttle provided in the temperature control valve 4 are set to the cooling water temperature. The cooling water held at the set temperature is sucked into the water pump 2 through the water passage 100. The excess cooling water in the water passage 103 due to the inflow of a part of the low-temperature system cooling water from the low-temperature combined water passage 302 to the temperature control valve 4 flows into the heat exchanger 21 from the high-temperature combined water passage 104 and recovers the recovered heat. To release. In the low temperature system cooling water circuit, the air cooler 11 and the lubricating oil cooler 12 are heat supply sources, and the recovered heat is released by the heat exchanger 21.

[0011]

1 is a block diagram of a cooling device for an internal combustion engine according to an embodiment of the present invention, and FIG. 2 is a functional explanatory diagram of the temperature control valve in FIG. The configuration will be described with reference to FIGS. In FIG. 1, 1 is an engine, 2 is a water pump, and 4
Is a temperature control valve, 100 to 103 are water passages, and a circuit constituted by these is called a high temperature system cooling water circuit. In the other unit, 3 is a water pump, 11 is an air cooler for supercharging, 12 is a lubricating oil cooler, 21 is a heat exchanger, and 200-
Reference numerals 205, 301, 303 and 304 are water passages, and a circuit constituted by these is called a low temperature system cooling water circuit. 10
Reference numeral 4 denotes a high temperature confluent water passage, which is a water passage 10 of the high temperature system cooling water circuit.
2 communicates with a water passage 304 that flows through the heat exchanger 21 of the low temperature system cooling circuit. 302 is a low temperature confluent water passage,
The water passage 301 of the low temperature system cooling water circuit communicates with the temperature control valve 4 of the high temperature system cooling water circuit. 111 to 112 are air passages for supercharging, 121 to 122 are passages for lubricating oil, and 4
Reference numerals 01 to 402 denote secondary cooling water passages for the heat exchanger 21.

In the first conventional example shown in FIG. 3, there are heat exchangers in the high temperature cooling water circuit and the low temperature cooling water circuit, and they have independent circuit configurations. In the second conventional example shown in FIG. The high-temperature cooling water circuit and the low-temperature cooling water circuit are merged into a single circuit configuration. In this embodiment, a high temperature combined water passage 104 and a low temperature combined water passage 302 are provided between the high temperature system cooling water circuit and the low temperature system cooling water circuit, and the temperature of the cooling water is detected in the water passage of the high temperature system cooling water circuit. A new circuit is formed by arranging a temperature adjusting valve 4 that controls the flow state of the cooling water in association with the water temperature.

Next, the operation will be described. In the high temperature system cooling water circuit, the heat generation source is around the cylinder of the engine 1, and the cooling water is sent from the water passage 101 to the water jacket by the water pump 2 to cool the cylinder appropriately to raise the temperature. Is discharged from the water passage 102. In the high temperature system cooling water circuit, the cooling water temperature is kept constant at an appropriate temperature in order to maintain a stable operating condition of the engine. This function will be described with reference to the function explanatory diagram (FIG. 2) of the temperature control valve 4 arranged in the water passage of the high temperature system cooling water circuit.
The temperature control valve 4 is a three-port directional control valve having a high temperature side throttle 41 and a low temperature side throttle 42 in a flow passage inside the valve. A control circuit 43 communicating with 41 and a control circuit 44 communicating with the low temperature side diaphragm 42 are provided.

If the temperature of the cooling water supplied to the water jacket of the engine is kept constant at 75 ° C., the temperature of the cooling water will gradually rise after the engine is started in the cold state. As shown in FIG. 2A, the entire amount of the cooling water flowing from the water passage 103 into the temperature control valve 4 flows into the water passage 100 and is supplied from the water passage 101 to the water jacket via the water pump 2. It circulates from 102 to 103 and the cooling water temperature rises. During this time, the inlet of the temperature control valve 4 on the side of the low-temperature combined water passage 302 is closed, and the entire amount of cooling water in the low-temperature system cooling water circuit is transferred from the water flow paths 301 and 303 to the heat exchanger 21.
The heat that has flowed into the internal water passage 304 and recovered is released.

When the temperature of the cooling water reaches the set temperature of 75 ° C., the temperature control valve 4 operates as shown in FIG. 2B so as to maintain the temperature of the cooling water. The inflow port on the side of the low-temperature confluent water passage 302 is opened, and a part of the cooling water of the low-temperature system cooling water circuit which flows in from the inflow port and the cooling water of the high-temperature system cooling water circuit which flows in from the water passage 103 are supplied in the water passage 100. Combine and mix. At this time, the temperature detector provided in the water passage 100 detects the cooling water temperature of the water passage, and the high temperature side and low temperature side control circuits 43,
The openings of the high-temperature side throttle 41 and the low-temperature side throttle 42 are controlled in association with the cooling water temperature via 44, and the water passages 100 to 7
The cooling water held at 5 ° C. is caused to be sucked into the water pump 2. Some of the low-temperature system cooling water flows into the temperature control valve 4 from the low-temperature confluent water passage 302, so that the surplus cooling water in the water passage 103 passes through the high-temperature confluent water passage 104 and flows to the low-temperature side in the water passage 304. It merges with the cooling water and releases heat in the heat exchanger 21.

In the low temperature system cooling water circuit, the heat recovered from the air cooler 11 and the lubricating oil cooler 12 is released by the heat exchanger 21, but generally the amount of heat generation is smaller than that in the high temperature system cooling water circuit.
It should be noted that it is effective to reduce the temperature of the air for supercharging in the air cooler 11 as much as possible in order to improve the output of the engine and the combustion. When the temperature control valve 4 is in the state of FIG. 2B, a part of the cooling water of the low temperature system cooling water circuit flows out from the water passage 302 to the high temperature system water passage 100 via the low temperature side throttle 42, A part of the cooling water of the low temperature system whose amount of water is reduced by the amount of the outflow and a part of the cooling water of the high temperature system circuit flowing from the high temperature combined water passage 104 are combined in the water passage 304 and radiated by the heat exchanger 21. Comparing the operation when the cooling water temperature is maintained near the set temperature in FIG. 1 with the operation in the second conventional example shown in FIG. 4, the high temperature side cooling water flowing into the water flow passage in the heat exchanger 21 is compared. Since the flow rate is reduced, assuming that the capacities of the heat exchangers are the same, the temperature drop of the primary side cooling water increases, and the cooling water temperature of the downstream water passage 201 of the cooling water pump 3 can be lowered. It is possible to supply low-temperature cooling water to the cooler 11.

[0017]

The cooling device for an internal combustion engine according to the present invention has a simple structure, maintains an appropriate temperature of the cooling water, and can achieve both improvement of engine output and improvement of combustion, and continuous operation under high load. Stable cooling performance can be maintained even during operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cooling device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a functional explanatory view of a temperature control valve 4 in FIG.

FIG. 3 is a configuration diagram of a cooling device for an internal combustion engine according to a first conventional example.

FIG. 4 is a configuration diagram of a cooling device for an internal combustion engine according to a second conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Water pump, 3 ... Water pump, 4 ... Temperature control valve, 11 ... Air cooler, 12 ... Lubricating oil cooler, 21
... heat exchanger, 100-103 ... water passage, 104 ... high-temperature combined water passage, 200-205 ... water passage, 301, 303,
304 ... Water passage, 302 ... Low temperature confluent water passage, 111, 1
12 ... Air passage, 121, 122 ... Lubricating oil passage, 40
1, 402 ... Secondary side cooling water passage (for heat exchanger).

Claims (1)

[Claims] 1. A water-cooled internal combustion engine equipped with a supercharger; a water pump (2) and a temperature control valve (4) capable of opening and closing a valve port and controlling the flow rate of the cooling water in conjunction with the temperature of the cooling water. And a high temperature system cooling water circuit constituted by the water pump, a water jacket around the cylinder of the engine (1), and a water passage (100 to 103) communicating between the temperature control valve in a closed circuit; (3) and an air cooler (11) for supercharging
, A lubricating oil cooler (12), a heat exchanger (21), and water passages (200 to 20) communicating with each other in a closed circuit.
5, 301, 303, 304), and a heat exchanger (2 in the low temperature system cooling water circuit from the upstream of the temperature control valve (4) in the high temperature system cooling water circuit.
A high temperature confluent water passage (104) for allowing a part of the high temperature system cooling water to flow into the upstream part of 1); and a low temperature system cooling water from the upstream part of the heat exchanger to the low temperature side cooling water inlet of the temperature control valve. And a low temperature confluent water passage (302) through which a part of the internal combustion engine flows.