JPH03179122A - Temperature control device of catalyst converter - Google Patents

Abstract

PURPOSE:To quickly activate a catalyst converter and to improve the exhaust gas treating performance by discharging cooling water in a water jacket in the periphery of an exhaust manifold to a reservoir tank to promote the rising of an exhaust gas temperature when an engine is cold. CONSTITUTION:A reservoir tank 15 is communicated with a circulation passage 12 for connecting between a water jacket in an engine main body 5 and a radiator 13 through a passage 14. Further, a water jacket 16 formed in such a manner as to cover the whole of an exhaust manifold 10 is attached to the engine main body 5. An inflow passage 17 separating from the circulation passage 12 between a water pump 11 and an engine main body 5 and an exhaust passage 18 communicating with the reservoir tank 15 are connected to the water jacket 16 to form a circulation passage for cooling water. When the engine is cold, the inflow passage 17 is closed by a thermostat valve 19, whereby the cooling water in the water jacket 16 can be discharged into the reservoir tank 15 through the exhaust passage 18.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a temperature control device for a catalytic converter that controls exhaust gas temperature so that a catalytic converter installed in an exhaust system of a vehicle efficiently performs a purifying action.

[Conventional technology]

A catalytic converter installed in a vehicle's exhaust system to purify exhaust gas has a predetermined activation temperature at which it can purify efficiently, but the purification efficiency decreases when the temperature is below the activation temperature, such as when the engine is cold. By the way, when the engine is cold like this, a large amount of HC (
Hydrocarbons) are generated, so it is necessary to quickly raise the catalytic converter to its activation temperature. Therefore, by introducing secondary air into the exhaust manifold upstream of the catalytic converter to re-burn the exhaust gas, and by supplying extra fuel there to promote combustion of the exhaust gas, the exhaust gas temperature Conventionally, measures have been taken to quickly raise the catalytic converter to its activation temperature by increasing the temperature. In addition, the catalytic converter is placed close to the engine body to reduce heat loss along the way, as shown in Figure 4. A sub catalytic converter 2 for mi mode is installed on the exhaust upstream side of the normal catalytic converter 1, or a bypass passage 4 is installed which is opened only during engine V & engine mode by actuating the actuator 8 as shown in Fig. 5. Installation of a catalytic converter 2 is also being carried out.

[Problem to be solved by the invention]

In the conventional example in which secondary air is introduced, the device configuration including its control device is large-scale, and in the case of a device that supplies extra fuel, there is a disadvantage that the fuel efficiency deteriorates. Furthermore, providing the sub-catalytic converter 2 is disadvantageous in terms of cost. Furthermore, in the case where the catalytic converter is disposed close to the engine body, there is another problem in that the catalyst is thermally deteriorated due to overheating and its durability is reduced. Therefore, the present invention has an advantageous configuration in terms of cost, while
Improves the exhaust gas processing performance of the catalytic converter when the engine is cold without deteriorating fuel efficiency, and improves the engine @+1! The purpose is to improve the durability of the subsequent catalytic converter.

[Means for Solving the Problems] For this purpose, the present invention provides a temperature control device for a catalytic converter installed in an exhaust system of a vehicle, which includes a water jacket covering an exhaust manifold, and a cooling water circulation passage of the water jacket. The system is equipped with an on-off valve device configured to close when the engine is cold and open after the engine is finished, and a reservoir tank passage for discharging the cooling water in the water jacket when the engine is cold. Regarding the structure of the water jacket covering the exhaust manifold, prior art related to Japanese Patent Application Laid-open No. 104711/1982 or Japanese Utility Model Application No. 14020/1983 can be found.

[For production]

With such means, when the engine is cold, the cooling water in the water jacket is discharged to the reservoir tank, and the water jacket forms a heat insulating space around the exhaust manifold to keep the exhaust manifold warm. Therefore, when the engine is cold, the exhaust gas temperature is promoted to rise, and the catalytic converter quickly reaches its activation temperature, improving exhaust gas treatment performance. Furthermore, after the engine warms up, cooling water circulates within the water jacket and cools the exhaust manifold, which suppresses the rise in exhaust gas temperature and prevents the catalytic converter from overheating, improving its durability.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the accompanying drawings. In FIG. 1, reference numeral 5 denotes an engine body 5, which includes an intake system that communicates with an air cleaner 7 via an intake manifold 6, and an exhaust system that communicates with an exhaust pipe 9 that grows a catalytic converter 8 via an exhaust manifold 1O. Be prepared. The catalytic converter 8 is arranged close to the engine body 5. Further, in the engine body 5, a cooling water circulation passage #i12 having a water pump 11 in the middle is connected to the radiator 13.
The water pump 11 and radiator 13 of this circulation passage 12 communicate with a reservoir tank 15 via a passage 14. Here, the engine body 5 is provided with a water jacket 16 that covers the entire exhaust manifold IO. An inflow passage 17 branching from the circulation passage 12 between the quarter pump 11 and the engine main body 5 and a discharge passage 18 communicating with the reservoir tank 15 are connected to the water jacket 16 to form a cooling water circulation passage. be done. Further, a thermostatic pulp 19 as an on-off valve device is installed in the middle of the inflow passage 17 so as to close the passage when the engine is cold and open the passage after the engine warms up. With the above configuration, when the engine is cold, the thermostatic pulp! 9 closes the inflow passage 17, the cooling water in the water jacket 16 is discharged into the reservoir tank 15 via the discharge passage 18. Therefore, a heat insulating space is formed around the exhaust manifold 10 covered by the water jacket 1B, and the heat insulating space keeps the exhaust manifold lO warm. Therefore, the temperature of the exhaust gas increases, and the catalytic converter 8 quickly reaches the activation temperature, improving the performance of treating exhaust gas such as HC. Note that j [converter 8
Radiant heat from the engine body 5 also has an advantageous effect on the temperature rise. Also, after the engine @ machine, thermostat pulp 19
opens the inflow passage 17, so the water jacket 1
Cooling water flows into and circulates in the exhaust manifold IO, and the exhaust manifold IO is water-cooled. Therefore, the temperature rise of the exhaust gas is suppressed, and overheating of the catalytic converter 8 is prevented, thereby improving the durability of the catalytic converter 8. FIG. 2 shows another embodiment of the invention. In this example,
The exhaust manifold 20 has a water jacket 2 around the exhaust passage! The other structure is almost the same as that of the previous embodiment. In this embodiment as well, when the engine is cold, a heat insulating space is formed in the water jacket 21 around the exhaust manifold 20 to keep the exhaust manifold 20 warm. Since cooling water flows in and the exhaust manifold 20 is water-cooled, substantially the same effects as in the previous embodiment are achieved. Note that the thermostatic valve 19 in the embodiment described above may be constituted by a solenoid valve 22 as shown in FIG. In this case, the solenoid valve 22 is controlled to open and close by a control unit 23, and a detection signal from an exhaust temperature sensor 24 installed in the exhaust pipe 9 upstream of the catalytic converter I is input to the control unit 23. The solenoid valve 22 is closed when the engine is cold and the exhaust temperature is below a predetermined value, and is opened after one engine whose exhaust temperature is above the predetermined value.

【Effect of the invention】

As described above, according to the present invention, when the engine is cold, the cooling water in the water jacket is discharged to the reservoir tank, and the water jacket forms a heat insulating space around the exhaust manifold to keep the exhaust manifold warm. Therefore, when the engine is cold, the exhaust gas temperature increases and the catalytic converter quickly reaches its activation temperature.
The exhaust gas treatment performance of the catalytic converter can be improved without deteriorating fuel efficiency. In addition, after the engine warms up, cooling water circulates within the water jacket and cools the exhaust manifold, which suppresses the rise in exhaust gas temperature and prevents the catalytic converter from overheating, increasing the durability of the catalytic converter. can be improved. And since there is no need for an expensive sub-catalytic converter,
This is an advantageous configuration in terms of cost.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is an overall configuration diagram showing another embodiment of the invention, FIG. 3 is a main part configuration diagram of still another embodiment, and FIG. This figure is an overall configuration diagram of one conventional example, and FIG. 5 is an overall configuration diagram of another conventional example. DESCRIPTION OF SYMBOLS 1... Catalytic converter, 2... Sub-catalytic converter, 3... Actuator, 4... Bypass passage, 5... Engine body, 6... Intake manifold, 7... Air cleaner, 8...Catalytic converter, 9...Exhaust pipe, IO...Exhaust manifold, 11...Quarter pump, ! 2... Circulation passage, 13... Radiator, 14... Passage, 15... Reservoir tank, 16... Water jacket, 17... Inflow passage, 18... Discharge passage, 19...・Thermostat valve, 20... Exhaust manifold, 21... Water jacket, 22... Solenoid valve, 23... Control unit, 24... Exhaust temperature sensor.

Claims (1)

[Claims] A temperature control device for a catalytic converter installed in the exhaust system of a vehicle, comprising a water jacket that covers the exhaust manifold and a cooling water circulation passage of the water jacket that is closed when the engine is cold, and after the engine is warmed up. 1. A temperature control device for a catalytic converter, comprising: an on-off valve device configured to open; and a reservoir tank passage through which cooling water in the water jacket is discharged when the engine is cold.