JPS6118009B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for cooling an exhaust gas purifying catalyst holding portion of an outboard motor.

Conventional outboard motors do not take any measures against exhaust gases, and emit exhaust gases containing CO and HC directly into the atmosphere or into the water. However, even in outboard motors, it is desirable to take measures against exhaust gases in order to prevent air pollution, and one method is to provide an exhaust gas purification (oxidation promotion) catalyst. However, by installing a catalyst in the exhaust gas passage,
When CO, HC, and other unburned gases are combusted (oxidation reaction) in the catalyst section, the area around the catalyst section becomes extremely high temperature, which can cause problems in handling the outboard motor and adversely affect the functions of other parts inside the outboard motor. On the other hand, directly cooling the catalyst section in order to prevent the adverse effects of the high temperature described above will reduce the engine performance and the catalyst function.

In view of the above circumstances, an object of the present invention is to provide a catalyst holder cooling device for an outboard motor that does not reduce the catalyst function or engine performance and can prevent heat damage to the outside due to the high temperature of the catalyst. In particular,
The gist thereof lies in a catalyst holder cooling device for an outboard motor, comprising a heat insulating layer provided outside the catalyst holder in an exhaust gas passage and a cooling zone provided outside the heat insulating layer. .

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

FIG. 1 is a conceptual cross-sectional view showing an example of an outboard motor not equipped with a cooling device according to the present invention. In the figure, exhaust gas discharged from the exhaust port 1a of the cylinder 1 passes through the exhaust gas passage 5 formed by the exhaust cover 2, the hole 3a of the engine holder 3, the exhaust pipe 4, etc., and is directed to the propeller as shown by arrow A. Part 6 is discharged into the water. At this time, the exhaust gas passes through the catalyst 7 provided in the exhaust pipe, and unburned gas is burned in the catalyst 7, resulting in a very high temperature near the catalyst 7, and as described above, the housing 8
The temperature of the outboard motor becomes high, making it difficult to handle the outboard motor, or causing heat damage such as malfunction or deformation of various built-in parts. Reference numeral 9 denotes a water draining device for preventing water adhering to the inner circumferential surface of the exhaust pipe 4 from flowing back through the exhaust pipe 4 and entering the cylinder 1 which wets the catalyst 7 when the outboard motor is tilted up. Yes, 10
is a water pump for supplying cooling water to the first part of the cylinder.

The cooling device according to the present invention is a cooling device provided outside the catalyst holding part of the exhaust gas passage as described above,
Hereinafter, FIG. 2, which is a conceptual cross-sectional diagram of the present device, will be explained. In the figure, the engine holder 3, exhaust pipe 4, exhaust gas passage 5, catalyst 7, housing 8, and water pump 10 are as described in FIG. The cooling device according to the present invention includes a heat insulating layer 11 provided on the outer periphery of the catalyst 7 holding portion of the exhaust gas passage 5 and a cooling zone 12 provided on the outer periphery of the heat insulating layer 11. In this embodiment, a large diameter portion 4a is formed in the exhaust pipe 4, and a cooling water passage 12 serving as a cooling zone is formed in the large diameter portion 7a in the shape of a water jacket. A heat insulating layer 11 formed of an inner cylinder 11a, an outer cylinder 11b, and a heat insulating material 11c filled in both cylinders 11a, 11b is disposed inside the large diameter portion 4a of the exhaust pipe, that is, inside the cooling water passage 12. The layer 11 itself is used as an exhaust gas passage constituent member, and the inner cylinder 11 thereof
A catalyst 7 is held inside a. A water conduit 13 is connected to the cooling water passage 12 from the water pump 10.
Supply unused cooling water as shown by arrow B through
After use, the cooling water is not used for cooling other components, but flows through the drain pipe 14 to the housing 8 as shown by arrow C.
It is configured so that it is discharged from the outboard motor. The water conduit 13 is branched from a water conduit 15 that supplies cooling water to the cylinder section. 16 is a cushioning material;
17 is a lower lid, 18 is a gasket, 19 is a water conduit holding seal, and 20 is a drive shaft.

The functions and effects of the cooling device according to the present invention are as follows. That is, the exhaust gas discharged from the cylinder passes through the catalyst 7 provided in the exhaust gas passage 5, and at this time, unburned gas and unburned oil in the exhaust gas are burned, so the catalyst 7 holding part becomes extremely high temperature. Become. However, since a cooling water passage 12 serving as a cooling zone is formed around the outer periphery of the catalyst holding part of the exhaust gas passage 5, the outside of the catalyst holding part is cooled, thus preventing heat damage to the outside due to the high temperature of the catalyst holding part. be able to. On the other hand, since the heat insulating layer 11 is formed between the cooling water passage 12 and the exhaust gas passage 5, the cooling effect of the cooling water passage 12 does not reach the exhaust gas passage 5 and the catalyst 7, and therefore the exhaust gas The gas passage 5 and the catalyst 7 are maintained at high temperatures, so there is no risk of deterioration of engine performance or catalyst function. In addition, by supplying unused cooling water directly from the water pump 10 to the cooling water passage 12, a sufficient cooling effect can be obtained, and the cooling water after heat exchange can be directly supplied without being used for cooling other components. By discharging cooling water from the housing 8 to the outside of the outboard motor in a visible manner, it is possible to determine whether there is an abnormality in the water pump, overheating, or whether the catalyst 7 is functioning effectively based on the presence or absence of discharged cooling water and its discharge condition. If the temperature of the exhaust cooling water is low, it means that the catalyst is not functioning effectively. Furthermore, by forming the cooling water passage 12 in a water jacket shape, a sound insulation effect can be exhibited, which can contribute to reducing the noise of the outboard motor.

As described above, if the device according to the present invention is used,
Heat damage caused by high temperatures near the catalyst holding part in the exhaust gas passage can be prevented, and since the catalyst holding part itself in the exhaust gas passage is not directly cooled, there is no risk of deterioration of engine performance or catalyst function. Further, by configuring as in the embodiment, sufficient cooling effect and sound insulation effect can be obtained, and it can be confirmed whether the pump and catalyst are functioning sufficiently.

Note that the cooling zone in the present invention is not limited to a cooling water passage connected to a water pump, but may also be a cooling air passage connected to an air pump or other various cooling means as necessary, and a heat insulating layer may also be used as necessary. Various formats can be used.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional conceptual diagram showing an example of an outboard motor without the present device, and FIG. 2 is a cross-sectional conceptual diagram showing the present device and the state in which the present device is installed. 5... Exhaust gas passage, 7... Catalyst, 11... Heat insulation layer, 12... Cooling zone (cooling water passage).

Claims (1)

[Claims] 1. A catalyst holder cooling device for an outboard motor, comprising: a heat insulating layer provided outside a catalyst holder in an exhaust gas passage; and a cooling zone provided outside the heat insulating layer.