JPH08232659A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE: To realize improvement in emissions and reduction in fuel consumption by providing an opening/closing valve for opening a bypass path in accordance with reduction of a load of an internal combustion engine, and providing a heat accumulator interposed in the bypass path. CONSTITUTION: A cooling water path 3 extended from a cooling water outlet 11 of an engine 1, leading to a radiator 2, is connected to a cooling water inlet 12 of the engine 1. A bypass main path 4 branches from the cooling water outlet 11 of the engine 1, to lead to a flow regulating valve 7, to extend bypass paths 41, 42. The one bypass path 41 is connected to a bottom wall of a heat accumulator 8 and here opened. During warming the engine, cooling water flowing out from the cooling water outlet 11, much flowing in the bypass path 41 from the bypass main path 4, is supplied to the heat accumulator 8. Cooling water of high temperature in the heat accumulator 8 is supplied to a water jacket and an oil warmer 14 via a warm water supply path 5 and the cooling water inlet 12. Thus by increasing a cylinder wall temperature of the engine 1, improving exhaust emission and reducing fuel consumption can be realized.

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 an internal combustion engine, and more particularly to a cooling device for an internal combustion engine which enables a rapid rise in cooling water temperature during warm-up to improve exhaust emission.

[0002]

2. Description of the Related Art In cooling an internal combustion engine (engine), the cooling water in the water jacket, which has been heated to a high temperature (100 ° C. or more), is sent to a radiator to radiate the heat, so that an appropriate temperature (80 ° C.) is reached.
This is done by recirculating the cooling water that has reached ~ 88 ° C) to the engine again. By the way, at the start of engine warm-up, the engine cooling water has dropped to about the outside temperature, and the engine cylinder wall is also cold,
The air-fuel ratio is made rich in fuel to ensure reliable engine startup and smooth engine rotation during warm-up. However, making the fuel rich often causes deterioration of exhaust emission and also lowers fuel consumption, and thus cannot meet the recent demands for exhaust regulations and energy saving.

[0003]

Therefore, the cooling water of an appropriate temperature during engine operation is stored in a heat accumulator, which is used at the time of engine warm-up to rapidly warm the engine cylinder to an appropriate temperature, thereby increasing the air-fuel ratio. It is possible to avoid fuel rich. However, providing a large-capacity heat storage device makes it difficult to secure an installation space, and causes an increase in weight of the heat storage device, which causes deterioration of fuel efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a cooling device for an internal combustion engine, which can effectively prevent deterioration of exhaust emission during warm-up by a small heat storage device provided in a cooling water system. And

[0005]

In the first configuration of the present invention, a cooling water passage 3 for returning the cooling water flowing out of the cooling water outlet 11 of the internal combustion engine 1 to the cooling water inlet 12 of the internal combustion engine 1 via the radiator 2. A bypass path 41 for directly returning the cooling water immediately after flowing out from the cooling water outlet 11 of the internal combustion engine 1 to the cooling water inlet 12 of the internal combustion engine 1, and a load state detecting means 7a for detecting a load state of the internal combustion engine, An on-off valve 7 that opens the bypass passage 41 according to a decrease in the load of the internal combustion engine 1;
The heat storage device 8 is provided in the bypass 41.

In the second configuration of the present invention, the cooling water passage 3 for returning the cooling water flowing out from the cooling water outlet 11 of the internal combustion engine 1 to the cooling water inlet 12 of the internal combustion engine 1 via the radiator 2.
And a first bypass passage 41 for circulating the cooling water immediately after flowing out from the cooling water outlet 11 of the internal combustion engine 1 to the cooling water inlet 12 of the internal combustion engine 1 bypassing the radiator 2, and the cooling water outlet 11 of the internal combustion engine 1. Immediately after flowing out of the cooling water, the cooling water is supplied to the vicinity of the heat-sensitive part of the heat-sensitive valve 6 provided in the cooling water passage 3 connecting the outlet of the radiator 2 and the internal combustion engine 1 and opened according to the cooling water temperature, and the cooling water passage 3 is Through the cooling water inlet 12 of the internal combustion engine 1
To the first bypass passage 41 for the second bypass passage 42 in response to the decrease in the load of the internal combustion engine 1, and the second bypass passage 42 for returning to the second bypass passage 42, the load state detecting means 7a for detecting the load state of the internal combustion engine, It is provided with a flow rate adjusting valve 7 for increasing the cooling water inflow ratio, and a heat storage device 8 provided in the first bypass passage 41.

In the third structure, the load state detecting means is composed of the pressure chamber 7a for driving the valve body operating diaphragm 71 of the flow rate adjusting valve 7 by introducing the intake manifold negative pressure of the internal combustion engine.

[0008]

In the first construction described above, when the engine is warmed up, the load on the internal combustion engine is small, so the on-off valve opens, and the cooling water flowing out from the cooling water outlet of the internal combustion engine flows into the bypass passage. The high-temperature cooling water stored in the heat accumulator is pushed out by the new inflow of cooling water, moves toward the cooling water inlet of the internal combustion engine, and quickly raises the cylinder wall temperature of the internal combustion engine. The cooling water flowing out from the internal combustion engine gradually becomes hot during warm-up, and the cooling water temperature immediately after flowing out from the cooling water outlet becomes sufficiently high. Then, this high-temperature cooling water flows into the heat storage device in the bypass passage and is stored therein. Since sufficiently high-temperature cooling water is stored, even if the heat storage unit is made small, a sufficient amount of heat can be obtained to quickly raise the cylinder wall temperature of the internal combustion engine that is warming up.
This rapid increase in the cylinder wall temperature eliminates the need to make the air-fuel ratio fuel-rich at the time of warm-up, thereby improving exhaust emission and reducing fuel consumption.

In the above-mentioned second structure, during warm-up or when traveling under a low load, the flow rate adjusting valve causes the cooling water inflow ratio to the first bypass passage to be larger than the cooling water inflow ratio to the second bypass passage. Then, the high temperature cooling water flowing out from the cooling water outlet of the internal combustion engine flows into the first bypass passage and is stored in the heat accumulator.
At the same time, since the supply of high-temperature cooling water to the vicinity of the heat-sensitive portion is reduced, the heat-sensitive valve tends to close, the amount of cooling water passing through the radiator decreases, and the cooling water temperature of the internal combustion engine rises as a whole. As a result, in addition to the improvement of exhaust emission at the time of warming up, smooth engine rotation and fuel consumption reduction at low load running are realized by reducing the quench area. During high-load running, the ratio of cooling water flowing into the second bypass path becomes large, and the supply of high-temperature cooling water to the vicinity of the heat-sensitive section increases, causing the heat-sensitive valve to open and the amount of cooling water passing through the radiator. And the cooling water temperature of the internal combustion engine decreases as a whole. As a result, knocking is suppressed and the output of the internal combustion engine is increased by improving the charging efficiency.

In the third structure, the load condition of the internal combustion engine is reliably detected by the intake manifold negative pressure of the internal combustion engine, and the electric valve control circuit is not required, so that the device structure is simplified.

[0011]

FIG. 1 shows an internal combustion engine (engine) according to the present invention.
2 shows the piping system of the cooling device. A cooling water passage 3 extending from a cooling water outlet 11 of the engine 1 reaches a radiator 2 and is connected to a cooling water inlet 12 of the engine 1 via the radiator 2. In the cooling water passage 3 from the radiator 2 to the cooling water inlet 12, a thermostat 6 as a heat sensitive valve is provided on the way.
Is provided. The thermostat 6 tends to open as the cooling water temperature rises due to the expansion of the wax in the heat-sensing portion provided therein, increasing the flow rate in the cooling water passage 3 passing through the radiator 2 and decreasing the engine cooling water temperature as a whole. When the cooling water temperature decreases, the thermostat 6 tends to close, reducing the flow rate in the cooling water passage 3 passing through the radiator 2 and increasing the engine cooling water temperature as a whole. In this way, the temperature of the cooling water supplied to the engine 1 is maintained substantially constant (80 ° C to 88 ° C). The cooling water is circulated by a water pump 13 attached to the engine 1. The cooling water reaching the cooling water inlet 12 cools the engine 1 through a water jacket in the engine 1 and is also supplied to an oil warmer 14. Be warmed up engine oil

The bypass main path 4 branches from the cooling water outlet 11 of the engine 1 to reach the flow rate adjusting valve 7. The bypass paths 41 and 42 extend from the flow rate adjusting valve 7, and one bypass path 41 stores heat. The bypass passage 42 is connected to the bottom wall of the container 8 and opens therein, and the other bypass passage 42 is connected to the cooling water passage 3 and opens near the heat-sensitive portion of the thermostat 6.

The hot water supply path 5 branches off from the cooling water outlet 11 and passes through the heater valve 51 and the heater core 52.
Has been reached. Hot water supply path 5 returning from the heater core 52
Is connected in the middle of the cooling water passage 3 toward the cooling water inlet 12, and the bypass passage 43 extending from the heat storage device 8 is connected to this return passage. The base end of the bypass passage 43 is located above the heat storage device 8.

The details of the structure of the flow rate adjusting valve 7 are shown in FIG.
A pressure chamber 7a is formed in the flow rate adjusting valve 7 by being partitioned by a diaphragm 71. The diaphragm 71 is formed by the pressure chamber 7a.
It is pressed to the left in the figure by a coil spring 72 provided inside. An operation rod 73 extending from the diaphragm 71 is inserted through an opening 751 of a partition wall 75 that divides the fluid chambers 7b and 7c, and a valve element 74 provided at the tip of the operation rod 73 closes an opening 411 of the bypass passage 41 to the fluid chamber 7c. are doing. The bypass main passage 4 is connected to the fluid chamber 7c from above and a bypass passage 42 extends from the fluid chamber 7b. The pressure chamber 7a communicates with an intake manifold (not shown) of the engine 1. In a high engine load state where the intake manifold negative pressure is small, the bypass main passage 4 and the bypass passage 42 communicate with each other to cool them as shown in the figure. Water flows. When the engine load decreases and the intake manifold negative pressure increases accordingly, the diaphragm 71 moves to the right, and along with this, the valve element 74 gradually separates from the opening 411 and from the bypass main path 4 to the bypass path 4
Cooling water begins to flow to 1. The amount of cooling water to the bypass 42 is reduced accordingly. During warm-up when the engine load is sufficiently small, the valve element 74 moves to a position where it closes the opening 751.
All the cooling water that has flowed in from the bypass main passage 4 is bypass passage 4
Flow to 1.

In the cooling device having such a structure, during warming up or running with a low engine load, much cooling water immediately after flowing out from the cooling water outlet 11 of the engine 1 flows from the bypass main passage 4 to the bypass passage 41. And is supplied to the heat storage device 8. The supplied cooling water pushes the high temperature cooling water accumulated in the upper part of the heat storage device 8 into the bypass passage 43 by natural convection, and the pushed high temperature cooling water flows from the return passage of the hot water supply passage 5 to the cooling water passage 3. After that, it reaches the cooling water inlet 12 of the engine 1 and is supplied to the water jacket and the oil warmer 14 in the engine 1. The high-temperature cooling water is supplied, the temperature of the cylinder wall of the engine 1 rises quickly, and fuel rich at the time of warm-up becomes unnecessary, so that exhaust emission is improved. In addition, the quench area is reduced during running under a low load, which realizes smooth engine rotation and reduced fuel consumption. And since the sufficiently high temperature (100 degreeC or more) cooling water immediately after flowing out from an engine is stored in the said heat storage device 8, compared with the case where 80 degreeC-88 degreeC cooling water after passing a radiator is stored. Even if the capacity of the heat accumulator is reduced by about 25% to 13.6% and the size is reduced, a sufficient amount of heat for engine temperature rise can be stored.

Further, in this embodiment, by supplying the high temperature cooling water to the oil warmer 14 of the engine 1, the oil temperature rapidly rises and its viscosity decreases especially during warm-up, which also reduces fuel consumption. Reduction is achieved. Further, since the high-temperature cooling water is also supplied to the heater core 52, the rising of heating is improved.

When the engine 1 is in a high load state during traveling, a large amount of cooling water immediately after flowing out from the cooling water outlet 11 starts to flow from the bypass main passage 4 to the bypass passage 42, and this high temperature cooling water is brought to the vicinity of the heat-sensitive portion. Supplied with thermostat 6
Will open up. As a result, the amount of cooling water passing through the radiator 2 increases, and the engine cooling water temperature as a whole becomes 8
The temperature is lower than 0 ° C. to 88 ° C., knocking is suppressed, the filling efficiency is improved, and the engine output is increased.

When the engine 1 changes from a high load state to a low load state during traveling, the cooling water immediately after flowing out from the cooling water outlet 11 starts to flow from the bypass main passage 4 to the bypass passage 41, whereby the inside of the heat storage unit 8 is stored. The high temperature cooling water is extruded and supplied to the engine 1. As a result, high-temperature cooling water is supplied to the engine 1 when the load is switched to a low load, lean combustion in the engine 1 is efficiently started, and fuel efficiency is improved. Changes in engine load and cooling water temperature at this time are shown in FIGS. 3 (1) and 3 (2). The solid line in FIG. 3 (2) shows the one in the present invention, and the broken line shows one without a heat accumulator. As is known from the figure, in the present invention, the water temperature rises rapidly when the engine is switched to the low load state. .

In the above embodiment, the flow rate adjusting valve 7, the thermostat 6, the heat accumulator 8 and the bypass passages 4, 41, 42, 43 connecting them can be integrated into a module.

Further, in the above embodiment, when it is not necessary to lower the cooling water temperature when the engine is under high load, it is not necessary to provide the bypass passage 42. In this case, instead of the flow rate adjusting valve 7 having the above structure, the intake air is taken. An on-off valve that opens and closes depending on the manifold negative pressure can be used.

Although the load state of the engine 1 is detected by the intake manifold negative pressure in the above embodiment, the load state may be detected by another method. In this case, the negative pressure actuated type flow rate adjusting valve is used. Or instead of the open / close valve,
A solenoid valve or the like operated by an electric signal from the control circuit can be used.

[0022]

As described above, according to the cooling system for an internal combustion engine of the present invention, the cooling water temperature at a low load of the internal combustion engine is rapidly increased by using a small heat storage device, thereby reducing exhaust emission and fuel consumption. It is possible to improve.

[Brief description of drawings]

FIG. 1 is a piping system diagram of a cooling device showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a flow rate adjusting valve.

FIG. 3 is a time chart showing the operation of the cooling device.

[Explanation of symbols]

 1 Engine (Internal Combustion Engine) 11 Cooling Water Outlet 12 Cooling Water Inlet 2 Radiator 3 Cooling Water Channel 41 Bypass Channel (First Bypass Channel) 42 Bypass Channel (Second Bypass Channel) 6 Thermostat (Heat Sensitive Valve) 7 Flow Control Valve ( Open / close valve) 7a Pressure chamber (load state detection means) 8 Heat accumulator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Fukunaga 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Stock Company Japan Automotive Parts Research Institute (72) Inventor Tokio Obama 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Shares (72) Inventor Houri Yamanaka, 1-1, Showa-cho, Kariya city, Aichi prefecture, Nihon Denso Co., Ltd. (72) Inventor, 1-1, 1-1, Showa-machi, Kariya city, Aichi prefecture Co., Ltd. (72) Inventor Mitsuru Inoue 1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd.

Claims (3)

[Claims] 1. A cooling water passage for returning cooling water flowing out from a cooling water outlet of an internal combustion engine to a cooling water inlet of the internal combustion engine via a radiator, and a cooling water immediately after flowing out of the cooling water outlet of the internal combustion engine directly to the internal combustion engine. A bypass path for returning to the cooling water inlet, load state detection means for detecting a load state of the internal combustion engine, an opening / closing valve for opening the bypass path according to a decrease in the load of the internal combustion engine, and a bypass path provided in the bypass path. And a cooling device for an internal combustion engine. 2. A cooling water passage for returning cooling water flowing out of a cooling water outlet of the internal combustion engine to a cooling water inlet of the internal combustion engine via a radiator, and a cooling water immediately after flowing out of the cooling water outlet of the internal combustion engine, bypassing the radiator. The first bypass passage for returning to the cooling water inlet of the internal combustion engine and the cooling water immediately after flowing out from the cooling water outlet of the internal combustion engine are provided in the cooling water passage connecting the outlet of the radiator and the internal combustion engine to the cooling water temperature. A second bypass passage for supplying the fluid near the heat-sensitive portion of the heat-sensitive valve to recirculate to the cooling water inlet of the internal combustion engine through the cooling water passage; load state detecting means for detecting the load state of the internal combustion engine; An internal combustion engine including a flow control valve for increasing a cooling water inflow ratio to the first bypass passage with respect to the second bypass passage according to a decrease in load, and a heat storage device provided in the first bypass passage. cold Rejection device. 3. The internal combustion engine according to claim 1, wherein the load state detecting means is constituted by a pressure chamber for driving a valve body operating diaphragm of the flow rate adjusting valve by introducing an intake manifold negative pressure of the internal combustion engine. Cooling system.