Cooling system for liquid-cooled machines

Abstract

A cooling system for an engine of a lawnmower. The engine has a muffler through which exhaust gases exit the engine and is cooled by a liquid coolant. The cooling system includes a heat exchanger operatively connected to the engine to receive the liquid coolant from the engine at a first temperature and return the liquid coolant to the engine at a lower temperature. A fan mounted above the heat exchanger is operable to draw or pull an air flow in a standard direction upward through the heat exchanger. The heat exchanger and fan are oriented in an inclined orientation such that the air flow is directed upward and away from the operator station of the lawnmower. The cooling system also has a generally tubular baffle surrounding the muffler at least partially isolating the engine from heat radiating from the muffler. The baffle is configured such that exhaust leaving the muffler causes air to be inducted into the areas between the muffler and the baffle by an aspiration effect created by the exiting exhaust gases.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The structure, operation, and advantages of the presently disclosed embodiment of the invention will become apparent when consideration of the following description is taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of a lawnmower embodying the invention;

FIG. 2 is an exploded perspective view of the lawnmower of FIG. 1 illustrating the engine cooling system;

FIG. 3 is a perspective view of a portion of the engine cooling system in a pivoted position;

FIG. 4 is a perspective view of the shielded muffler of the engine cooling system of FIG. 2;

FIG. 5 is a side view of the shielded muffler of the engine cooling system of FIG. 2; and

FIG. 6 is an end view of the shielded muffler of the engine cooling system of FIG. 2.

Claims

1. A lawnmower comprising: a chassis;an operator station on said chassis;a plurality of ground engaging wheels rotatably mounted on said chassis;an engine mounted on the chassis and operatively connected to drive said ground engaging wheels, said engine having a muffler through which exhaust gases exit said engine and said engine being cooled by a liquid coolant;an engine cooling system comprising: a heat exchanger operatively connected to said engine to receive said liquid coolant from said engine at a first temperature and return said liquid coolant to the engine at a lower temperature;a fan mounted above the heat exchanger and operable to draw an air flow in a standard upward direction through said heat exchanger, wherein said heat exchanger and fan are oriented in an inclined orientation such that the air flow is directed upward and away from the operator of the lawnmower; anda generally tubular baffle surrounding the muffler at least partially isolating the engine from heat radiating from the muffler, wherein the baffle is configured such that exhaust gases leaving the muffler causes air to be inducted into the areas between the muffler and the baffle by an aspiration effect created by the exiting exhaust gases.

2. The lawnmower of claim 1 wherein the baffle has an outer end portion that defines a venturi tube.

3. The lawnmower of claim 2 wherein the baffle is concentric with and surrounds the muffler to define an annular air passage therebetween and an exhaust pipe on a discharge end of the muffler directs the exhaust gases into the venturi tube.

4. The lawnmower of claim 3 wherein the baffle has a multi-sided shape.

5. The lawnmower of claim 4 wherein the baffle has an octagonal or hexagonal shape.

6. The lawnmower of claim 4 wherein the distance Db across shield flats of the baffle is about 120% to about 130% of the diameter Dm of the muffler, the distance Do across shield flats at an outlet of the venturi tube is about 175% to about 225% of the diameter Dp of the exhaust pipe and the distance Dt from the muffler to the baffle outlet is equal to the length Lp of the exhaust pipe plus about 80% to about 120% the exhaust pipe diameter Dp.

7. The lawnmower of claim 1 wherein the heat exchanger and fan are mounted onto the chassis such that they can be pivoted to provide access to the lower side of the heat exchanger.

8. The lawnmower of claim 1 wherein the operator station is formed by a seat mounted on the chassis.

9. A method for increasing cooling of a lawnmower engine cooling system, the lawnmower comprising a chassis, an operator station on said chassis, an engine mounted on the chassis, the engine cooling system comprising a heat exchanger operatively connected to said engine, a fan mounted above the heat exchanger and operable to draw an air flow in a standard upward direction through said heat exchanger, a generally tubular baffle surrounding the muffler at least partially isolating the engine from heat radiating from the muffler, wherein the baffle is configured such that exhaust gases leaving the muffler cause air to be conducted into the areas between the muffler and the baffle by an aspiration effect created by the exiting exhaust gases, said method comprising the steps of: pivot mounting said heat exchanger and fan onto said chassis;orienting said heat exchanger and fan in an inclined position so as to direct said exhaust gases upward and away from said operator station;wherein the pivot mounting step facilitates rotating of said heat exchanger about its pivot axis to provide access to the lower side of the heat exchanger and said engine.

10. The method as recited in claim 9, wherein the pivot mounting and orienting steps function to enhance the natural convection process of heat from the engine through the heat exchanger.