WO2009143634A2

WO2009143634A2 - Exhaust pipe accessory

Info

Publication number: WO2009143634A2
Application number: PCT/CA2009/001180
Authority: WO
Inventors: Klaus F. Nowak
Original assignee: Nowak Klaus F
Priority date: 2008-05-02
Filing date: 2009-04-29
Publication date: 2009-12-03
Also published as: WO2009143634A3; CA2630268A1

Abstract

An exhaust duel has a venturi into which exhaust gases from an internal combustion engine flow. and an inner chamber having an υouter frusto-conical shaped wall. The wall increases in cross- section downstream and terminates at a nozzle from which the exhaust gases discharge. The inner chamber is perforated and is surrounded by an inner chamber into which exhaust gases may flow. The nozzle has a curved inner wall which increases in cross-section downstream such that the exhaust gases which discharge through the nozzle and which are adjacent to the inner wall tend to adhere to the latter wall by reason of the Coanda effect. A number of such exhaust ducts are incorporated into an exhaust assembly which also includes a catalytic converter and a resonator.

Description

TITLE OF THE INVENTION EXHAUT PIPE ACCESSORY

FIELD OF THE INVENTION

This invention relates to an assembly through which exhaust gases from an internal combustion engine flow before they fire released to the atmosphere and more particularly to an ex haust assembly provided with one or more exhaust ducts each of which being composed of a venturi and a diverging cone.

BACKGROUND OF THE INVENTION

In my Canadian patent no 624,629 issued on July 25. 1961, I describe a muffler composed of an outer shell which is clamped to the tail pipe of an internal combustion engine. An inner shell is positioned within the outer shell and is surrounded by a layer of noise-absorbing material The outer shall has an upstream element of uniform diameter and a downstream element of gradually increasing diameter.

The subject invention is an improvement on the muffler described in my patent. The apparatus is suitable as a final stage through which exhaust gases pass be lore they are expelled to the atmosphere. The apparatus is also suitable for use in an exhaust system in conjunction with a conventional catalytic converter, resonator and muffler.

The apparatus of the subject invention carries out the function of a conventional muffler and effects a reduction of back pressure through the acceleration of the exhaust gases There arc

many benefits that flow from this: 1. Lower back pressure means less energy required to expel burnt gases;

2. Increased scavenging effect during the valve overlap;

3 A more efficient gas exchange dining the combustion cycle,

4 Increased work for the same fuel consumption;

5. Reduced fuel consumption and pollution for an equivalent output, and

6. Lower level of sound pressure (dBA)

There is in many instances, a reduction in the consumption of fuel by a motor vehicle equipped with the subject apparatus with resulting reduction in the quantity of pollutants released to the atmosphere. Furthermore, in most cases there is a significant improvement in the useful or nel horsepower generated by an internal combustion engine where its exhaust flows through the apparatus of the invention. That is because more expansion of the exhaust gases occurs in the apparatus of the invention than in a conventional muffler. More expansion has at least two useful results, one is that the amount of useful work generated by the engine is increased and secondly, less energy is required to generate such work with resulting reduction in fuel consumption.

Trie weight of the apparatus of the invention is significantly Iess than that of most con- ventional mufflers with resulting savings in the cost of production of the apparatus. Furthermore the reduction in weight contributes toward lower fuel consumption.

SUMMARY OF THE INVENTION

Briefly, the apparatus of my invention is an exhaust duct through which exhaust gases from an internal combustion engine are adapted to flow. The exhaust duct includes a venturi having an inlet at its upstream end into which the exhaust gases are adapted to flow and an inner chamber into which gases from trip venturi are adapted to flow. The inner chamber is bounded by an outer first wall which commences at the venturi. increases in cross-section downstream there- of and which terminates at a nozzle through which the exhaust gases are adapted to discharge.

One of the preferred features of the nozzle is that it has a curved inner wall which increases in cross-section downstream such that the exhaust gases which discharge through the nozzle and which are adjacent Io the curved inner wall tend to adhere to it by reason of the Coanda effect.

Another preferred feature of the exhaust duct is that it includes an outer chamber within which the inner chamber is disposed. The outer chamber has an outer second wall spaced apart from the first wall by an annul an space which contains noise-absorbing material and which is isolated from the atmosphere. The first wall is perforated such that the exhaust gases within the inner chamber may flow into the annular space,

DESCRIPTION QF THE DRAWINGS

The exhaust assembly of the invention is described with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a conventional exhaust assembly through which exhaust gases from an internal combustion engine flow;

Figure 2 is a perspective view of a multi-stage exhaust assembly consisting of a number of exhaust ducts of my invention mounted within a housing;

Figure 3 is a perspective view, in more detail, of the assembly of Figure 2;

Figure 4 is an elevation., in larger scale, of one of the exhaust ducts illustrated in Figures 2 and 3;

Figure 4a is an elevation of the exhaust duct in conjunction with a booster;

Figure 5 is a simplified elevation of the assembly illustrated in Figures 2 and 3; and

Figure 6 is a perspective view, in larger scale, of the tail pipes of the assembly illustrated in Figures 2 and 3.

Like reference characters refer to like parts throughout the description of the drawings. DESCRIPTION OF PREFERRED EMBODIMENTS

With reference; to Figure 1 , a conventional exhaust assembly is illustrated. The assembly consists of a catalytic converter 10 at the upstream end of the assembly, a resonator 12 further downstream of the cataliytic c

onverter and a muffler 14 at the downstream end of the assembly Exhaust gases generated within a conventional internal combustion engine (not illustrated) flow through pipe 16 to the catalytic converter, then downstream through the resonator and muffler and discharge to the atmosphere through outlet 20.

With reference to Figure 3, the assembly of my invention consists of a pair of hollow upstream and downstream cylinders 20, 22 respectively, and. a number of tail pipes, generally 24 downstream of the two cylinders. Exhaust gases generated by an internal combustion engine (not illustrated) enter the upstream cylinder tlnυuyh pipe 26 and flow to a catalytic converter mounted in an upstream compartment 20a of the cylinder. From the catalytic converter, the gases flow through exhaust duct 28 and discharge from the cylinder in two streams Two parallel pipes 30a,b act as conduits for the two streams.

The catalytic converter is conventional while the exhaust duct is one of the subject inventions of this application. The exhaust duct is described in detail below.

Downstream cylinder 22 functions as a resonator and contains the conventional components for carrying out that function. The cylinder also however contains two exhaust ducts 34a,b. The latter ducts arc mounted in parallel and each is connected to a separate pipe 30a,b for receipt ot one of the streams of exhaust gases. Exhaust ducts 34a,b are of the same construction as ex haust duet 28.

The exhaust gases which flow through exhaust ducts 34 discharge into and are separated into four streams in conduits 36 and each conduit is connected to a separate exhaust duct 38. The latter conduits and exhaust ducts comprise the exhaust pipes 24 of the assembly and the exhaust gases which issue from them discharge to the atmosphere. The exhaust ducts in the tail pipes arc of the same construction as the previously mentioned exhaust ducts.

The exhaust ducts of the invention are described with reference to Figure 4. Each exhaust duct, generally 39, includes a ventuπ 40 at the upstream end. Exhaust gases flow through conduit 42 into the venturi and issue from it into an inner chamber, generally 44.The inner chamber is bounded by an outer first frusto-conical shaped outer watl 46. The Wall commences at the venturi, increases in cross-section downstream and terminates at a nozzle 48.

Nozzle 48 has a curved inner wall 50 which increases in cross-section downstream. The curvature of the inner wall is such that the exhaust gases adjacent to it tend to adhere to it by reason of the Coanda effect. The inner wall accordingly causes the exhaust gases which pass through the nozzle to discharge from it in the form of a cone which enlarges downstream of the nozzle.

The internal diameter of the inlet of the venturi, which is also the internal diameter of conduit 42, is preferably about 60 percent of the cross-sectional area of the conical pipe at its outlet 40b where the pipe is connected to the upstream edge of the nozzle.

The inner chamber is surrounded by an outer annular chamber, generally 52, having an outer second frusto conical shaped wall 54 which is concentric with the first outer wall 46. The two outer walls 54, 46 define outer and inner boundaries, respectively, of the outer chamber.

The outer wall 46 of the inner chamber is perforated and provides the exhaust eases within the inner chamber access to the outer chamber. Preferably the combined area of the perforations in wall 46 is approximately 40 to 50 percent of the total area of the wall.

The outer chamber is isolated from the atmosphere so that exhaust gases within the outer chamber do not leak into the atmosphere. The outer chamber contains conventional noise- absorbing material 56

With reference to Figure 4a. exhaust duct 60 is the same as the exhaust duct 39 depicted in Figure 4. To the duct is added a booster, generally 62. Ambient air from outside the exhaust duct enters ihe booster through inlet 62a and discharges through outlet 62b.

The booster is hollow and is provided with an inlet 62a, an outlet 62b and an outer wall 64 The outer wall has a frusto-conical upstream component 64a and a radially outwaidly extending downstream component 64b which terminates at the outlet. The outer wall surrounds the exhaust duct and is concentric with it while the downstream componeπi extends downstream from the exhausl duct.

The curvature of the outlet component takes advantage of the Coancla effect to bend the gases lhat discharge from the outlet radially outward.

There is a relatively small annular space, generally 68, between the downstream edge of the nozzle and the outer wall of the booster. A venturi effect occurs in that space as ambient air outside the exhaust element flows through the booster and through the space. The venturi effect results in a decrease in the pressure of the exhaust gases upstream of the nozzle with resulting reduction in the energy required Io expel exhaust gases from the exhaust duct. The pressure drop also causes an improvement in the gas exchange during the comhuslion cycle in the engine.

The pressure is further decreased by the Coanda effect at the outlet of the boosler.

Wi th reference to Figures 5 and 6 a number of exhaust ducts of the invention arc shown in the multi-stage exhaust assembly illustrated in these drawings. In the first stage, a first exhaust conduit 100 is mounted in upstream chamber 102 and is downstream of and in fluid flow relationship with a catalytic converter (not illustrated). Exhaust, gases from that exhaust duct flovv through two openings 104 in the downstream wall of the chamber into a pair of conduits 106 The gases are in two so-called "first" streams.

Conduits 106 extend 1O the upstream ends of two so-called ''second" exhaust ducts 108 in the second stage of the exhaust assembly. The two conduits act as a passage or means through which each first stream flows to a separate second exhaust duct. The two second exhaust ducts are mounted in downstream chamber 110.

Exhaust gases from the two second exhaust ducts flow through four openings 112 in the downstream wall of the downstream chamber and into four conduits 114. The gases are accordingly now in four so-called "Third " streams.

Conduits 114 extend to the upstream ends of four "third" exhaust ducts 1 16 in the thud stage of the assembly. This stage is the final stage in the assembly and the exhaust ducts as generally referred to as the "exhaust pipes". Exhaust gases which pass through the exhaust pipes are expelled to the atmosphere. The exhaust pipes accordingly act as the passage or means by which ihc exhaust gases are expelled to the atmosphere.

It will be understood, that the exhaust assembly of the invention can have additional stages in which the number of exhaust ducts through which the exhaust gases flow remains the same or changes. The number of ducts can for example, progressively increase downstream of the initial stages.. It may be useful, for example, to have additional stages where noise attenuation is particularly important since each exhaust duel of the assembly acts as a muffler and contributes to the overall reduction in the volume of noise from the engine.

The exhaust duct of the invention may be composed of metallic or non-metallic material For example, the non-metallic material may be carbon fibre, fibreglass or a combination of other non-metallic materials. The exhaust duct is particularly suitable for use in conjunction with a diescl locomotive or a large internal combustion engine of a ship.

Tt will be understood that modifications can be made to the structure of the exhaust duct and assembly illustrated and described herein without departing from the scope and purview of the invention as defined in the appended claims.

Claims

I claim:

1. A exhaust duct through which exhaust gases from an internal combustion engine are adapted to flow comprising: a vcniuri having an inlet at its upstream end into which said exhaust gases are adapted to flow; an inner chamber into which gases from said venturi are adapted to flow, said inner chamher being bounded by an outer first wall which commences at said venturi, increases in cross-section downstream thereof and which teπninates at a nozzle through which said exhaust gases are adapted to discharge.

2. The exhaust duct of claim 1 wherein said nozzle has a curved inner wall which increases in cross-section downstream such that said exhaust gases which discharge through said nozzle and which are adjacent to said inner wall tend to adhere to the latter said wall by reason of the Coanda effect,

3. The exhaust duct of claim 1 further including an outer chamber within which said inner chamber is disposed, said outer chamber having an outer second wall spaced apart from said first wall by an annular space which contains noise-absorbing material and which is isolated from the atmosphere, said first wall being perforated such that said exhaust gases within said inner cham her may flow into said annular space.

4. The exhaust duct of claim 1 further including a booster tube disposed radially outward of said outer chamber, said booster tube having an inlet for receipt of ambient air from outside said exhaust duct, an outer wall having an upstream component which tapers downstream, a down-

stream component which is radially outwardly extending and which terminates at an outlet, said booster outer wall being spaced apart from said nozzle such that said ambient air may flow between the latter said wall and said noz/.le.

5. In combination with a plurality of exhaust ducts as claimed in any one of claims 1 to 4, a catalytic converter and a resonator, a first one of said exhaust ducts being in fluid flow relationship with said catalytic convener and bring downstream thereof; means for causing exhaust gases issuing from said first exhaust duct to flow to a second one of said exhaust duct; means for causing exhaust gases issuing from said second exhaust duct to flow to a third one of said exhaust duct; and means for discharging exhaust gases issuing from said third exhaust duel to the atmosphere.

6. In combination with a plurality of exhaust ducts as claimed in any one of claims 1 to 4, a catalytic converter and a resonator, a first one of said exhaust ducts being in fluid flow relationship with said catalytic converter and being downstream thereof; means for separating cxhausi gases issuing from said first exhaust duct into a plurality of first streams; means for causing each said first stream to flow to a separate one of a plurality of second said exhaust ducts; means for separating exhaust gases issuing from each said second exhaust duct into a plurality of second streams; means for causing each said second stream to flow to a separate one of a plurality of third said exhaust ducts, and means for discharging exhaust gases issuing from said third exhaust ducts to the atmosphere.

7. A exhaust duct through which exhaust gases from an internal combustion engine are adapted to flow comprising: a venturi having an inlet at its upstream end into which said exhaust- gases are adapted to flow; an inner chamber into which gases from said venturi are adapted to flow, said inner chamber being bounded by an outer first wall which commences at said venturi, increases in cross-section downstream thereof and which terminates at a nozzle through which said exhaust gases are adapted to discharge, said nozzle having a curved inner wall which increases in cross-section downstream such that said exhaust gases which discharge through said nozzle and which are adjacent to said inner wall tend to adhere to the latter said wall by reason of 1he Coanda effect; an outer chamber within which said inner chamber is disposed, said outer chamber having an outer second walJ spaced apart from said first wall by an annular space which contains noise-absorbing material and which is isolated from the atmosphere, said first wall being perforated such that said exhaust gases within said inner chamber may flow into said annular space.

8. The exhaust duct of claim 7 further including a booster tube disposed radially outward of said outer chamber, said booster tube having an inlet for receipt of ambient air from outside said exhaust duet, an outer wall having an uptream component which tapers downstream, a downstream component which is radially outwardly extending and which terminates at an outlet, said booster outer wall being spaced apart from said nozzle such that said ambient air may flow between the latter said wall and said nozzle.

9. In combination -with a plurality of exhaust ducts as claimed in any one of claims 7 to 8, a catalytic converter and a resonator, a first one of said exhaust ducts being in fluid flow relationship with said catalytic converter and being downstream thereof, means for causing exhaust gases issuing from said first exhaust duct to flow to a second one of said exhaust duct; means for causing exhaust gases issuing from said second exhaust duct to flow to a third one of said exhaust duct; and means for discharging exhaust gases issuing from said third exhaust duct to the atmosphere.

10. In combination with a plurality of exhaust ducts as claimed in any one of claims 7 to 8, a catalytic convener and a resonator, a first one of said exhaust ducts being in fluid flow relationship with said catalytic converter and being downstream thereof; means for separating exhaust gases issuing from said first exhaust duct into a plurality of first streams; means for causing each said first stream to flow to a separate one of a plurality of second said exhaust ducts; means for separating exhaust gases issuing from each said second exhaust duct into a plurality of second streams; means for causing each said second stream to flow to a separate one of a plurality of third said exhaust ducts, and means for discharging exhaust gases issuing from said third exhaust ducts to the atmosphere.