1. Field of the Invention
The present invention relates to a water-cooled type internal combustion engine mounted to a farming motor vehicle such as a tractor and a combine harvester and more particularly to a device adapted to cool a muffler of such an engine by means of a radiator fan.
2. Description of the Prior Art
Conventionally an engine for a farming motor vehicle is provided with a muffler which is projected upward largely from an engine room of the motor vehicle. In recent years in an attempt to improve an external appearance of the motor vehicle, the muffler is mounted within the engine room.
As such a muffler of the type mounted within the engine room has been known the one disclosed in Japanese Provisional Utility Model Publication No. 1986-32510.
Here, in the engine room extending in the fore and rear direction of the motor vehicle there are arranged a radiator, a radiator fan and an engine body in order from foreside while a muffler body is arranged in a space on the lateral side of the engine body so as to extend in the fore and rear direction. An exhaust outlet pipe is projected downward from the upwind side end portion of the muffler body, and a muffler cover is mounted to the muffler body with a cooling air passage provided therebetween for cooling the muffler. A portion of cooling air flow delivered by means of the radiator fan is introduced into the muffler cooling air passage so as to pass therethrough.
In the aforementioned conventional embodiment there is the advantage in that the muffler body is adapted to be cooled by means of the cooling air flow delivered from the radiator fan so as to prevent the temperature within the engine room from being raised by a heat of the muffler body and to cool down the temperature of an exhaust gas discharged from the outlet pipe.
There is, however, a following disadvantage associated with the conventional embodiment. That is, since it is required to increase a quantity of the cooling air flow delivered by means of the radiator fan when the temperature of the exhaust gas from the outlet pipe is intended to be further cooled down, the radiator fan becomes large in size and resultantly the engine itself becomes large in overall size.