Split Flow Exhaust Deflector

Abstract

A split flow exhaust deflector for a grass moving machine such as a ZTR mower includes a sheet metal body mounted to a lower surface of a muffler of an internal combustion engine, spaced from the lower surface of the muffler to form a pair of channels through which exhaust gasses from the engine pass from the muffler and substantially outwardly through the pair of channels to a pair of locations adjacent a left side surface and a right side surface of the muffler.

Description

FIELD OF THE INVENTION

This invention relates to grass mowing machines, and specifically to exhaust systems for mowers having rear mounted engines such as zero turn radius (“ZTR”) mowers with independently powered left and right drive wheels controlled with hydrostatic transmissions.

BACKGROUND OF THE INVENTION

Grass mowing machines such as ZTR mowers may have internal combustion engines mounted at the rear of the mower frame or platform behind the operator seat. ZTR mowers also have at least one independently powered drive wheel on each side of a frame. Hydrostatic transmissions transmit power from the engine to each of the left and right drive wheels, either in forward or reverse. The pair of hydrostatic transmissions, or dual hydrostatic transmission, may be driven through a belt and pulley arrangement by the engine crankshaft. The hydrostatic transmission(s) may be mounted to the rear-of the vehicle frame adjacent the engine, under and/or behind the operator seat.

A ZTR mower exhaust system may include one or more exhaust pipes extending from the cylinder head or exhaust manifold. The exhaust system also may include a muffler attached to the exhaust pipe(s). Hot exhaust gasses may exit the muffler through openings in the muffler, or through a tail pipe directed downwardly or to the side of the ZTR mower. A plate also may be provided to extend over the muffler openings and may be spaced from the openings sufficiently to direct the exhaust gas stream toward the side of the ZTR mower.

Additionally, a ZTR mower may have a heat shield to protect persons, objects and the grass surface from the muffler itself and the exhaust gas stream. For example, the heat shield may be a curved sheet metal member attached to the ZTR mower frame and extending behind and underneath the muffler.

The heat shield, however, does not prevent grass browning if a ZTR mower is parked for a period of time. This is a result of hot engine cooling air combining with the exhaust stream into a concentrated stream. The resulting heat load may damage or kill the grass under the muffler and heat shield.

There is a need for a exhaust deflector for a ZTR mower that reduces or eliminates grass browning if it is parked for a period of time. There is a need for a exhaust deflector for a ZTR mower that reduces the heat load on grass under the muffler and heat shield.

SUMMARY OF THE INVENTION

A split flow exhaust deflector for a ZTR mower includes a one-piece sheet metal member attached to a lower portion of a muffler on a rear-mounted engine, including a generally horizontal planar lower surface spaced under the lower portion of the muffler. The member forms a left channel leading to a left side opening, and a right channel leading to a right side opening. The left and right side openings are adjacent a left side surface and a right side surface of the muffler such that exhaust gasses from the engine exit openings in the lower portion of the muffler and the flow splits to pass through left and right channels to the left and right side openings at or adjacent the left and right side surfaces of the muffler. The split flow exhaust deflector reduces or eliminates grass browning if a ZTR mower is parked, and reduces the heat load on grass under the muffler and heat shield.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the underside of a ZTR mower with a split flow exhaust deflector according to a preferred embodiment of the invention.

FIG. 2 is a perspective view of a split flow exhaust deflector according to a preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In one embodiment shown in FIGS. 1-2, a grass mowing machine such as zero turning radius (“ZTR”) mower 100 may have rear mounted engine 102 with one or more exhaust pipes 104 connected to and extending from the cylinder head or exhaust manifold. The ZTR mower may include an oblong or generally box-shaped muffler 106 attached to the exhaust pipe(s) and located generally behind and under the rear mounted engine. The muffler may be a two-part member including a top or upper portion 107 secured to a bottom or lower portion 108. Hot exhaust gasses may exit the muffler through downwardly directed openings 109 in the muffler's bottom portion.

In one embodiment, the ZTR mower may include heat shield 112 extending generally over the rear and bottom of the muffler. Additionally, the ZTR mower may include rear panel 114 attached to the frame and extending around the rear of the engine.

In one embodiment, split flow exhaust deflector 110 may be a one-piece sheet metal member attached to bottom or lower portion 108 of muffler 106. For example, the split flow exhaust deflector may be aluminized steel or similar sheet metal. The split flow exhaust deflector may have a generally horizontal planar lower surface that is spaced under the lower surface of the muffler, and spaced from the downwardly directed openings, by about 20 mm up to about 50 mm.

In one embodiment, the split flow exhaust deflector may form a first or left channel 122 leading to a first or left side opening 116, and a second or right channel 124 leading to a second or right side opening 118. The left and right side openings of the split flow exhaust deflector may be at or, adjacent to (i.e., within about 50 mm) the left side surface 128 and right side surface 130 of the muffler. The length of the split flow exhaust deflector between the left and right openings may be substantially the same as, or within about 100 mm of, the width of the muffler between the left and right side surfaces. Thus, the channels formed by the split flow exhaust deflector may extend substantially across the width of the muffler so that exhaust gasses can exit the channels at or adjacent the left and right side surfaces of the muffler.

In one embodiment, channel 122 may have a shorter length than channel 124 of the split flow exhaust deflector. This is because the downwardly directed openings in the muffler may be positioned substantially closer to one side of the muffler than the other side. For example, the left channel may be less than about 100 mm in length and the right channel may be greater than about 200 mm in length. Each channel may have a width of at least about 50 mm but preferably less than about 200 mm.

In one embodiment, the split flow exhaust deflector may include a central portion 126 between the left and right channels. The area of the central portion may be substantially similar or larger than the area defined by the downwardly directed openings in the muffler. For example, the width or diameter of the central portion may be at least about 75 mm, which may be greater than the width of each channel.

In one embodiment, flange 120 may be provided around the perimeter of the split flow exhaust deflector, including along the edge of each channel and the central portion. Threaded fasteners may be inserted through openings in the flange to secure the split flow exhaust deflector to the muffler.

In one embodiment, the split flow exhaust deflector may split the exhaust stream into two streams, and direct each stream outwardly to the left and right side openings 116, 118 at or adjacent the left and right side surfaces 128, 130 of the muffler. Once an exhaust stream reaches the left or right side of the muffler, it can mix with the engine cooling air in a mixing zone. As a result, the mixed air has a lower concentrated head load to the ground, and prevents grass browning.

Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.

Claims

1. A split flow exhaust deflector, comprising:

a one-piece sheet metal member attached to a lower portion of a muffler on a rear-mounted engine and having a generally horizontal planar lower surface spaced under the lower portion of the muffler, the member forming a left channel leading to a left side opening, a right channel leading to a right side opening, the left and right side openings adjacent a left side surface and a right side surface of the muffler such that exhaust gasses from the engine exit openings in the lower portion of the muffler and pass through the left and right channels to the left: and right side openings at or adjacent the left and right side surfaces of the muffler..

2. The split flow exhaust deflector of claim 1 wherein the left channel is shorter in length than the right channel.

3. The Split flow exhaust deflector of claim 1 wherein the muffler is a two-part member including the lower portion secured to an upper portion.

4. The split flow exhaust deflector of claim 1 further comprising a wider central portion between the, left and right channels.

5. The split flow exhaust deflector of claim 1 further comprising a heat shield positioned below and rearwardly of the muffler.

6. A split flow exhaust'deflector, comprising:

a pair of channels under a muffler, the pair of channels being unequal in length;

a central portion between the pair of channels and positioned under a plurality of exhaust openings in a muffler;

each channel having a side opening adjacent a side surface of the muffler.

7. The split flow exhaust deflector of claim 6 wherein the central portion has an area substantially the same as an area defined by the exhaust openings in the muffler.

8. The split flow exhaust deflector of claim.6 further comprising a flange along each of the pair of channels and fasteners securing the flange to the muffler.

9. The split flow exhaust deflector of claim 6 wherein the width of each channel is less than the width of the central portion.

10. The split flow exhaust deflector of claim 6 wherein the split flow exhaust deflector is a one-piece sheet metal body.

11. A split flow exhaust deflector, comprising:

a sheet metal body mounted to a lower surface of a muffler connected to an internal combustion engine of a zero turn radius mower, and spaced from the lower surface of the muffler to form a pair of channels between the sheet metal body and the lower surface of the muffler through which exhaust gasses from the engine-pass from'the muffler and substantially outwardly through the-pair of channels to a pair of locations adjacent a left side surface and a right side surface of the muffler.

12. The split flow exhaust deflector of claim 11 wherein the sheet metal body includes a central portion mounted over a plurality of exhaust openings in the lower surface of the muffler.

13. The split flow exhaust deflector of claim 11 wherein the muffler is generally box-shaped.

14. The split flow exhaust deflector of claim 11 wherein the muffler is connected to the internal combustion engine by at least one exhaust pipe.