JPH04187810A - Cooling and temperature keeping device for exhaust manifold - Google Patents

Abstract

PURPOSE:To enhance warming performance of a catalytic converter so as to reduce thermal deformation of an exhaust manifold by sucking liquid staying in a space of the exhaust manifold to deliver it into a tank by a water pump by means of an exhaust gas cooling and temperature keeping controller. CONSTITUTION:At a low temperature of exhaust gas, an exhaust gas cooling and temperature keeping controller 14 sucks water staying inside a space 4 of an exhaust manifold 1 by means of a water pump 7, to deliver it into a tank 9, and then, the space 4 of the exhaust manifold 1 is in an almost vacuum state. Accordingly, the exhaust gas can be introduced into a catalytic converter 12, warming performance of which can be enhanced. At a high temperature of the exhaust gas in a high speed operation or the like, water cooled by a radiator 6 is delivered into the space 4 so that a multi-branched pipe main body 2 can be cooled. Therefore, it is possible to prevent the multi-branched pipe main body 2 of the exhaust manifold 1 from being exposed to the exhaust gas of a high temperature so as to reduce thermal deformation due to the exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling/warming device for an exhaust manifold constituting an exhaust system of an automobile.

[Conventional technology] Exhaust manifolds make up the exhaust system of automobiles.

Exhaust gas flows through the exhaust pipe and the catalytic converter installed in the exhaust pipe, and is affected by the heat of this exhaust gas.

For example, when the vehicle is running at high speed, the exhaust gas becomes hot and the exhaust manifold is exposed to this exhaust gas, making it susceptible to thermal deformation. Additionally, during a cold start, warm-up performance is required to quickly warm up the catalytic converter, but as the exhaust manifold receives the driving wind, the exhaust gas becomes supercooled and does not immediately reach a temperature sufficient to activate the catalyst in the catalytic converter. There is.

Therefore, as a device aimed at preventing such thermal deformation of the exhaust manifold and improving the warming performance of the catalytic converter, a cooling bag W for the exhaust manifold (shown in Figure 3) is known, for example, as disclosed in Japanese Utility Model Application Publication No. 126507/1983. ing.

In the figure, each exhaust port 102 of an engine 101 is connected to a low-temperature exhaust gas manifold 103A and a high-temperature exhaust gas manifold 103B, and is constituted by an exhaust gas manifold branched into two passages. Each exhaust gas manifold 103A and 103B is provided with a low-temperature exhaust gas cutoff valve 104A and a high-temperature exhaust gas cutoff valve 104B as control valves, and these are connected to a negative pressure valve 105.
It is opened and closed by

A liquid-cooled exhaust gas cooling section 106 is provided in the high-temperature exhaust gas manifold 103B.

This exhaust gas cooling unit 106 is connected to a liquid cooling circulation device 107 that is independent of the cooling water path of the engine 101, thereby forming a liquid cooling exhaust gas cooling device 108.

In the above configuration, when the exhaust heat amount of exhaust gas is high,
The low temperature exhaust gas cutoff valve 1 of the low temperature exhaust gas manifold 103A is activated by the valve control signal output from the valve control device.
04A is closed, and the high temperature exhaust gas cutoff valve 104B of the high temperature exhaust gas manifold 103B is opened. By circulating the coolant in the liquid-cooled exhaust gas cooling device 108, the high-temperature exhaust gas manifold 103B is cooled without being affected by the load condition of the engine 101.

On the other hand, when the exhaust heat amount of the exhaust gas is low, the exhaust gas is passed through the low-temperature exhaust gas manifold 103A in the opposite manner to the above to prevent the exhaust gas from being overcooled.

[Problem to be solved by the invention]

However, in the conventional exhaust manifold cooling device, when the exhaust heat amount of the exhaust gas is high, the high temperature exhaust gas manifold 103B is cooled and its thermal deformation is prevented. When the exhaust heat amount of the gas is low, the exhaust gas is cooled by the running wind while passing through the low-temperature exhaust gas manifold 103A, and the amount of temperature drop before reaching the catalytic converter 109 is large, and the exhaust gas is overheated. Cooling could not be sufficiently prevented, and the warm-up performance for the catalytic converter remained poor.

The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent thermal deformation of the exhaust manifold when the exhaust gas temperature is high, and to prevent the exhaust gas from being thermally deformed when the exhaust gas temperature is low such as during a cold start. An object of the present invention is to provide an exhaust manifold cooling/heating device that can sometimes sufficiently prevent overcooling of exhaust gas and improve the warming performance for a catalytic converter.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention surrounds the multi-branched pipe main body through which exhaust gas flows with an outer pipe to form an integral space between the multi-branched pipe main body and the outer pipe. A circulation waterway is connected to the exhaust manifold, which is made up of a first
A branch waterway is provided between the on-off valve and the water pump, a tank for storing liquid is connected to the branch waterway, and a tank for storing liquid is connected to the branch waterway.
A second on-off valve is installed in the part leading to the tank, and an exhaust temperature sensor is installed to detect the exhaust temperature of exhaust gas in the exhaust path from the exhaust manifold to the catalytic converter, and the input side is connected to the exhaust temperature sensor. The output side is also connected to the water pump, the first on-off valve, and the second on-off valve, and when the exhaust gas temperature is high, the first on-off valve is opened and the second on-off valve is opened.
Exhaust gas controlled to close the first on-off valve and open the second on-off valve and further operate the water pump for a predetermined time when the temperature of the exhaust gas is low, so as to close the on-off valve and operate the water pump. It is equipped with a cooling and heat retention control device.

[For production]

In the present invention, when the exhaust gas temperature is high, the space of the exhaust manifold is filled with liquid, and the exhaust gas cooling and heat retention control device opens the first on-off valve and closes the second on-off valve. and the water pump is running. Therefore, when the water pump operates, the liquid circulates through the exhaust manifold and the circulation waterway connected to it, and the liquid cooled by the radiator is carried into the space of the exhaust manifold through the circulation waterway, and the liquid is cooled. The liquid cools the multi-branch pipe body of the exhaust manifold.

On the other hand, when the temperature of the exhaust gas is low, the exhaust gas cooling and heat retention control device closes the first on-off valve, opens the second on-off valve, and operates the water pump for a predetermined period of time.

Therefore, the liquid in the space of the exhaust manifold is sucked by the water pump and transported into the tank, and the space of the exhaust manifold is brought into a near-vacuum state. This near-vacuum state functions as a kind of heat insulator, keeping the exhaust gas flowing inside the multi-branch pipe body of the exhaust manifold warm.

〔Example〕

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

FIG. 1 shows an exhaust manifold cooling/warming device according to an embodiment of the present invention.

In the figure, 1 is an exhaust manifold, which surrounds a multi-branch pipe main body 2 consisting of branch pipes 2A, 2B, 2C, and 2D through which exhaust gas flows, and each branch pipe 2A, 2B, 2C, and 2D of the multi-branch pipe main body 2. Outer tubes 3A, 3B.

3C, 3D and connecting pipes 3E, 3E, 3E that connect the outer pipes 3A, 3B, 3C, 3D, and between the multi-branched pipe body 2 and the outer pipes 3A, 3B, 3C, 3D. One space 4
is formed.

Reference numeral 5 denotes a circulation waterway, both ends of which are connected to the outer pipe 3A and outer pipe 3D of the exhaust manifold 1, and communicate with the space 4 of the exhaust manifold 1.

A radiator consisting of a radiator 6 is interposed in the middle of the circulation waterway 5.

A water pump 7 is interposed in the circulation waterway 5 upstream of the radiator 6. water pump 7
The motor 7A is directly connected to.

Further, a first on-off valve 8 is interposed in the circulation waterway 5 on the downstream side of the radiator 6, and a first actuator 8A for operating the first on-off valve 8 is connected.

One end of a branched waterway 10 is connected to a portion 5A of the circulation waterway 5 between the radiator 6 and the water pump 7, and a tank 9 for storing water is connected to the other end of this branched waterway 10. A communication port 9A is provided on the top surface of the tank 9 so that the air inside can be released to the atmosphere. Branch waterway 1
A second on-off valve 11 is interposed in the middle of 0. A second actuator IIA that operates the second on-off valve 11 is connected to the second on-off valve 11.

12 is a catalytic converter, and this catalytic converter 12 is provided with an exhaust temperature sensor 13 for detecting the temperature of exhaust gas.

14 is an exhaust gas cooling and heat retention control device, the input side of which is connected to the exhaust temperature sensor 13, and the output side connected to the motor 7.
A, first actuator 8A, second actuator II
A, and when the exhaust gas temperature is high, the first on-off valve 8
When the temperature of the exhaust gas is low, the first on-off valve 8 is closed and the second on-off valve 11 is opened, and the water pump 7 is operated. Outputs a control command to operate for a predetermined period of time.

Next, the operation of this embodiment will be explained.

Figure 1 shows the state when the exhaust gas temperature is high (for example, when driving at high speed). In this state, the exhaust manifold 1
The space is filled with water, and the exhaust temperature sensor 13
As a result, the temperature of the exhaust gas in the catalytic converter 12 is detected, and a signal thereof is sent to the exhaust gas cooling/warming control device 14 . A command is sent from the exhaust gas cooling heat retention control device 14 to the first actuator 8A to open the first on-off valve 8, a command is sent to the second actuator IIA to close the second on-off valve 11, and a command is sent to the second actuator IIA to close the second on-off valve 11. A command is sent to motor 7A to operate motor 7. Therefore, the first on-off valve 8 is opened, the second on-off valve 11 is closed,
Water pump 7 is activated.

As a result, water circulates through the exhaust manifold 1 and the circulation channel 5 connected thereto, and the water cooled by the radiator 6 is carried into the space 4 of the exhaust manifold 1 via the circulation channel 5, and the water is cooled. The water cools the multi-branch pipe main body 2 of the exhaust manifold 1, preventing its thermal deformation, and also cools the exhaust gas to an appropriate temperature, thereby preventing the catalytic converter 12 from overheating.

On the other hand, FIG. 2 shows a state when the exhaust gas temperature is low (for example, at the time of a cold start).

When the temperature of the exhaust gas is low, the exhaust gas temperature sensor 13 detects the temperature of the exhaust gas in the catalytic converter 12 and sends a signal thereof to the exhaust gas cooling and heat retention control device 14 .

A command is sent from the exhaust gas cooling heat retention control device 14 to the first actuator 8A to close the first on-off valve 8, a command is sent to the second actuator IIA to open the second on-off valve 11, and a command is sent to the second actuator IIA to open the second on-off valve 11. A command is sent to motor 7A to operate. Therefore, the first on-off valve 8 is closed, the second on-off valve 11 is opened, and the water pump 7 is operated.

In this state, the water in the circulation waterway 5 is prevented from circulating by the first on-off valve 8, so the water in the space 4 of the exhaust manifold 1 is sucked by the water pump 7 and carried into the tank 9, and the water in the exhaust manifold The inside of the space 4 of No. 1 is in a state close to vacuum. When the inside of this space 4 becomes close to vacuum, the second on-off valve 11 is closed and the water pump 7 is stopped. The space 4 is maintained in a near-vacuum state and functions as a kind of heat insulator, so that the exhaust gas flowing through the multi-branch pipe main body 2 of the exhaust manifold 1 is kept warm.

Next, from the state in which the space 4 of the exhaust manifold 1 described above is close to vacuum (the first on-off valve 8 and the second on-off valve 11 are closed), the first on-off valve 8. By opening the second on-off valve 11, water in the tank 9 is transported to the space 4 and filled with water. Then, when the second on-off valve 11 is closed with the first on-off valve 8 open and the water pump 7 is operated, the state shown in FIG. 1 is obtained.

According to the above configuration, when the temperature of the exhaust gas is low, the water in the space 4 of the exhaust manifold 1 is sucked by the water pump 7 and transported into the tank 9 by the exhaust gas cooling and heat retention control device 14. The inside of the space 4 of the exhaust manifold 1 is in a nearly vacuum state. Therefore, the near-vacuum state in this space 4 acts as a kind of heat insulator for the multi-branch pipe body 2 of the exhaust manifold 1, keeping the exhaust gas flowing through the multi-branch pipe body 2 of the exhaust manifold 1 warm, and driving the vehicle. Exhaust gas that has not been cooled by outside air can be guided to the catalytic converter 12 even when it is exposed to wind, and the warm-up performance of the catalytic converter 12 can be improved.

Further, due to the near-vacuum state in the space 4 of the exhaust manifold 1, it is also possible to prevent sound transmitted from the exhaust gas flowing through the multi-branch pipe main body 2.

Furthermore, when the exhaust gas temperature is high during high-speed operation, water cooled by the radiator 6 is carried into the space 4 of the exhaust manifold 1 via the circulation waterway 5, and this cooled water is used to cool the exhaust manifold l. The multi-branch pipe main body 2 can be cooled. Therefore, the multi-branch pipe main body 2 of the exhaust manifold 1
The catalytic converter 12 can be prevented from being exposed to high-temperature exhaust gas and thermal deformation caused by the exhaust gas can be reduced, and the exhaust gas can be cooled to an appropriate temperature to prevent the catalytic converter 12 from overheating.

Note that in this embodiment, the exhaust gas temperature sensor l3 is provided in the catalytic converter I2, but the exhaust gas temperature sensor 13 may be provided in the exhaust path from the exhaust manifold 1 to the catalytic converter 13.

Further, in this embodiment, the first on-off valve 8 is interposed in the circulation waterway 5 at the downstream side of the radiator 6. It can also be provided on the upstream side between the radiator 6 and the branch waterway 10.

Furthermore, in this embodiment, the water pump 7 is installed in the circulation waterway 5, located upstream of the radiator 6, but it is installed in the circulation waterway 5, located downstream of the radiator 6. You can also do that.

In that case, the branch waterway 10 needs to be located at the downstream side of the water pump 7 in the circulation waterway 5 and provided between the first on-off valve 8 and the water pump 7 .

In this embodiment, water is used as an example of the liquid circulating in the circulation waterway 5 and the exhaust manifold 1, but the liquid is not limited to this.

〔Effect of the invention〕

As described above, according to the present invention, when the exhaust gas temperature is low, the exhaust gas cooling heat retention control device causes the liquid in the space of the exhaust manifold to be sucked by the water pump and transported into the tank, and the liquid is The inside of the manifold space is in a near-vacuum state. Therefore, the near-vacuum state in this space acts as a kind of heat insulator for the multi-branched pipe body of the exhaust manifold, keeping the exhaust gas flowing through the multi-branched pipe body of the exhaust manifold warm, even when it is exposed to the traveling wind. Exhaust gas that has not been cooled by outside air can be guided to the catalytic converter, and the warm-up performance of the catalytic converter can be improved.

Furthermore, the near-vacuum state in the space of the exhaust manifold makes it possible to prevent sound from passing through the exhaust gas flowing through the multi-branch pipe body.

Furthermore, when the temperature of exhaust gas is high during high-speed operation, etc., the liquid cooled by the radiator is carried into the space of the exhaust manifold through the circulation channel, and this cooled liquid is used in the multi-branch pipe body of the exhaust manifold. can be cooled. Therefore, it is possible to prevent the multi-branched pipe main body of the exhaust manifold from being exposed to high-temperature exhaust gas, and to reduce thermal deformation caused by the exhaust gas.

[Brief explanation of drawings]

FIG. 1 is a partially sectional configuration diagram of an exhaust manifold cooling and heat retention device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the operating state of the cooling and heat-insulating device for the exhaust manifold. FIG. 3 is a configuration diagram of a conventional cooling device for an exhaust manifold. [Explanation of symbols of main parts] 1...Exhaust manifold 2...Multi-branch pipe body 3A, 3B, 3C, 3D...Outer pipe 4...Space 5...Circulation waterway 6... Radiator (radiator) 7... Water pump 8... First on-off valve 9... Tank 10... Branch waterway 11... Second on-off valve 12... Catalytic converter 13... Exhaust temperature Sensor 14: Exhaust gas cooling and heat retention control device. Figure 2 Figure 3

Claims (1)

[Claims] (1) A circulation waterway is connected to the exhaust manifold, which is formed by surrounding the multi-branched pipe main body through which exhaust gas flows with an outer pipe to form an integrated space between the multi-branched pipe main body and the outer pipe, so as to communicate with the space. A radiator, a water pump, and a first on-off valve are each installed in the circulation waterway, and the first valve is located downstream of the water pump in the circulation waterway.
A branch waterway is provided between the on-off valve and the water pump, a tank for storing liquid is connected to the branch waterway, a second on-off valve is interposed in the part of the branch waterway up to the tank, and further, an exhaust temperature sensor that detects the temperature of exhaust gas in the exhaust path from the exhaust manifold to the catalytic converter; the input side is connected to the exhaust temperature sensor, and the output side is connected to the water pump, the first on-off valve, and the second on-off valve; When the exhaust gas temperature is high, the first on-off valve is opened and the second on-off valve is opened.
Exhaust gas controlled to close the first on-off valve and open the second on-off valve and further operate the water pump for a predetermined time when the temperature of the exhaust gas is low, so as to close the on-off valve and operate the water pump. A cooling/heating device for an exhaust manifold, comprising: a cooling/heating control device.