US20100018193A1

US20100018193A1 - Vortex-enhanced exhaust manifold

Info

Publication number: US20100018193A1
Application number: US12/178,892
Authority: US
Inventors: Edward CARR
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-07-24
Filing date: 2008-07-24
Publication date: 2010-01-28

Abstract

An exhaust manifold for handling exhaust from an internal combustion engine includes an empty main body and an exhaust duct. The main body is defined by a generally cylindrical wall, an aperture and a main body longitudinal axis. The exhaust duct is configured to pass through the wall to terminate inside the main body with an exhaust duct longitudinal axis that is offset from the main body longitudinal axis so that exhaust gasses introduced from the exhaust duct into the main body form a vortex as the gasses progress to the aperture in the main body.

Description

FIELD OF THE INVENTION

The present application relates generally to the handling of exhaust from an internal combustion engine and, more specifically, to a vortex-enhanced exhaust manifold.

BACKGROUND OF THE INVENTION

Within each cylinder of an internal combustion engine, without regard for the configuration or the type of fuel used, there is a cycle of intake, compression, power and exhaust. In general, a combination of fuel and an oxidizer (typically air) enter the cylinder on the intake phase of the cycle. After the compression and power phases of the cycle, exhaust gases are expelled from the cylinder, through a valve and into the input port of an exhaust duct.
In some cases, an output port of the exhaust duct simply releases the exhaust gasses to the surrounding atmosphere. However, it is far more typical that the output port of the exhaust duct passes the exhaust gasses to an exhaust manifold, which collects exhaust gasses from several exhaust ducts and delivers the exhaust gasses to an exhaust pipe, perhaps through a catalytic converter and/or a muffler.
Typically, there is a back pressure on the valves that release the exhaust gasses to the input ports of the exhaust ducts. It has been recognized that the back pressure adversely affects the efficiency of the engine.

SUMMARY

Exhaust ducts from an internal combustion engine enter a vortex-enhanced exhaust manifold in an otherwise empty main body at a position that is offset from the longitudinal axis of the main body. A resultant vortex of gas swirling in the main body assists in drawing further gasses out of the exhaust ducts and into the main body, thereby leading to a decrease in back pressure at the input port of the exhaust ducts.
In accordance with an aspect of the present invention there is provided an exhaust manifold for handling exhaust from an internal combustion engine. The exhaust manifold includes an empty main body and an exhaust duct. The main body is defined by a generally cylindrical wall, an aperture and a main body longitudinal axis. The exhaust duct is configured to pass through the wall to terminate inside the main body, the exhaust duct having an exhaust duct longitudinal axis that is offset from the main body longitudinal axis so that exhaust gasses introduced from the exhaust duct into the main body form a vortex as the gasses progress toward the open end of the main body.
Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the drawings, which show by way of example, embodiments of the invention, and in which:

FIG. 1 illustrates, in perspective view, a prior art exhaust manifold;

FIG. 2 illustrates, in perspective view, a vortex-enhanced exhaust manifold having a generally cylindrical main body with a closed end and an open end according to an embodiment of the present invention;

FIG. 3 illustrates, in perspective view, a section of the cylindrical main body of FIG. 2;

FIG. 4 illustrates, in an end view, the section of FIG. 3;

FIG. 5 illustrates, in a perspective view, a first variation of the vortex-enhanced exhaust manifold of FIG. 2 according to an embodiment of the present invention;

FIG. 6 illustrates, in a perspective view, a second variation of the vortex-enhanced exhaust manifold of FIG. 2 according to an embodiment of the present invention;

FIG. 7 illustrates an end view of a section of a main body of a third-variation vortex-enhanced exhaust manifold according to an embodiment of the present invention;

FIG. 8 illustrates a perspective view of an exhaust duct for use in a fourth-variation vortex-enhanced exhaust manifold according to an embodiment of the present invention;

FIG. 9 illustrates a perspective view of an exhaust duct for use in a fifth-variation vortex-enhanced exhaust manifold according to an embodiment of the present invention;

FIG. 10 illustrates, in perspective view, a sixth-variation vortex-enhanced exhaust manifold according to an embodiment of the present invention;

FIG. 11 illustrates, in a sectional view, the sixth-variation vortex-enhanced exhaust manifold of FIG. 10;

FIG. 12 illustrates, in perspective view, a seventh-variation vortex-enhanced exhaust manifold according to an embodiment of the present invention; and

FIG. 13 illustrates, in a sectional view, the seventh-variation vortex-enhanced exhaust manifold of FIG. 12.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 illustrates a prior art exhaust manifold 100. The prior art exhaust manifold 100 includes a first exhaust duct 102A having a first exhaust duct input port 104A, a second exhaust duct 102B having a second exhaust duct input port 104B and a third exhaust duct 102C having a third exhaust duct input port 104C. The prior art exhaust manifold 100 includes a main body 108, which receives exhaust gasses from each of the exhaust ducts 102A, 102B, 102C at a respective exhaust duct output port (not shown). The prior art exhaust manifold 100 also includes an output port 106. Each of the input ports 102A, 102B, 102C have a similar cross-sectional area, which is similar to a cross-sectional area of the output port 106.
FIG. 2 illustrates a vortex-enhanced exhaust manifold 200 constructed in accordance with an embodiment of the present invention. The vortex-enhanced exhaust manifold 200 includes a first exhaust duct 202A having a first exhaust duct input port 204A, a second exhaust duct 202B having a second exhaust duct input port 204B and a third exhaust duct 202C having a third exhaust duct input port 204C. The vortex-enhanced exhaust manifold 200 includes a cylindrical wall 210 defining a main body 208. The main body 208 receives exhaust gasses from each of the exhaust ducts 202A, 202B, 202C at a respective exhaust duct output port (not explicitly referenced). The vortex-enhanced exhaust manifold 200 also includes an output port 206. Each of the input ports 204A, 204B, 204C (collectively or individually 204) have a similar cross-sectional area, while a cross-sectional area of the output port 206 is greater than the cross-sectional area of the input ports 204.
In contrast to the prior art exhaust manifold 100, which is constructed so that the exhaust ducts 102A, 102B, 102C terminate at the wall of the main body 108, the exhaust ducts 204 pass through the wall 210 to terminate inside the main body 208.
FIG. 3 illustrates, in perspective view, passage of an exhaust duct 302 through a wall 310 of a main body 308 of an exhaust manifold, only a portion of which is illustrated in FIG. 3. The exhaust duct 302 has an exhaust duct output port 303. As is shown in FIGS. 2 and 3 but better illustrated in FIG. 4, which is an end view of the exhaust manifold portion illustrated in FIG. 3, a longitudinal axis 412 of the exhaust duct 302 is perpendicular to, and axially offset from, a longitudinal axis 414 of the main body 308.
As the end of the main body 208 that is opposite the output port 206 (not shown in FIG. 2) is closed, in operation, exhaust gasses that enter the main body 208 via the exhaust ducts 202A, 202B, 202C (collectively or individually 202) exit the main body 208 via the output port 206. Furthermore, based on the axial offset of the longitudinal axis of the exhaust ducts 202 from the longitudinal axis of the main body 308, a vortex of swirling exhaust gasses extends from the output ports of each exhaust duct 202 to the output port 206 of the main body 208.
FIG. 4 includes a first set of arrows 416 representative of the vortex of swirling exhaust gasses as the exhaust gasses leave the exhaust duct 302 and enter into the main body 208 of the vortex-enhanced exhaust manifold 200. A second set of arrows 418 represents of the vortex of swirling exhaust gasses as the vortex is disturbed by the extension of the exhaust duct 302 into the main body 308.
The applicants consider that the vortex-enhanced exhaust manifold 200 reduces back pressure on the valves on the internal combustion engine from which the vortex-enhanced exhaust manifold 200 receives exhaust gasses. This reduction in back pressure may be attributed to at least two parameters of the vortex-enhanced exhaust manifold 200. The first of these parameters is that, as the vortex of swirling exhaust gasses pass the exhaust duct output port 303 (FIG. 3), a region of low pressure may be produced around the exhaust duct output port 303. This region of low pressure may pull, encourage, or draw the exhaust gasses within the exhaust duct output port 303 into the main body 208 of the vortex-enhanced exhaust manifold 200.
The second of these parameters is the greater volume of the main body 208 of the vortex-enhanced exhaust manifold 200 when compared to the main body 108 of the prior art exhaust manifold 100.
The increased volume allows the main body 208 to act as an accumulator. It is known that the exhaust gasses from the engine do not come to the vortex-enhanced exhaust manifold 200 as a steady flow. Instead, the exhaust gasses from the engine come as pulses as each cylinder pushes out its combustion by-products in turn. The Applicants anticipate that the vortex of exhaust gasses in the main body 208 will have a pulsating flow.
Computation Fluid Dynamic (CFD) Analysis has been used to compare the vortex-enhanced exhaust manifold 200 to the prior art exhaust manifold 100. According to the CFD Analysis, the peak pressures at the exhaust duct input ports 104A, 104B, 104C of the prior art exhaust manifold 100 average around 4 000 Pa. In contrast, the peak pressures at the exhaust duct input ports 204 of the vortex-enhanced exhaust manifold 200 average around 1 500 Pa.
Additionally, the CFD Analysis illustrated that the prior art exhaust manifold 100 exhibits relatively high peak pressures at all three exhaust duct input ports 104A, 104B, 104C when only one of the exhaust duct input ports 104A, 104B, 104C is receiving exhaust gasses from a cylinder in the engine. In contrast, the CFD Analysis illustrated that the vortex-enhanced exhaust manifold 200 exhibits relatively high peak pressures at only one of the three exhaust duct input ports 204 when only one of the exhaust duct input ports 204 is receiving exhaust gasses from a cylinder in the engine. The single exhaust duct input port 204 exhibiting relatively high peak pressure is the exhaust duct input port 204 receiving the exhaust gasses from the cylinder in the engine.
The CFD Analysis also showed that patterns of variability of the pressure at a given exhaust duct input port 104 of the exhaust duct input ports 104A, 104B, 104C of the prior art exhaust manifold 100 are due to firing of other cylinders into another exhaust duct input port 104 that is down stream of or in front of (closer to the output port 106) the cylinder associated with the given exhaust duct input port 104 of the prior art exhaust manifold 100. In contrast, the CFD Analysis showed that pressures at the exhaust duct input ports 204 followed roughly equivalent patterns of variability.
FIG. 5 illustrates a first variation 500 of the vortex-enhanced exhaust manifold 200 of FIG. 2, wherein exhaust gasses exiting the output port 206 of the main body 208 pass through an output duct in the form of a first funnel 520. The first funnel 520 has a first funnel input port that matches the output port 206 of the main body 208. The first funnel 520 also has a first funnel output port 506 whose cross-sectional area is less than the cross-sectional area of the output port 206 of the main body 208. The first funnel 520 also implements a 90 degree turn between the first funnel input port and the first funnel output port 506. The first-variation vortex-enhanced exhaust manifold 500 attempts to mimic the 90 degree turn leading to output port 106 and the exhaust-duct-diameter of the output port 106 as present in the prior art exhaust manifold 100 (FIG. 1).
As stated above, according to the CFD Analysis, the peak pressures at the exhaust duct input ports 204 of the vortex-enhanced exhaust manifold 200 average around 1 500 Pa. In contrast, the peak pressures at the exhaust duct input ports 204 of the first-variation vortex-enhanced exhaust manifold 500 average around 3 000 Pa.
FIG. 6 illustrates a second variation 600 of the vortex-enhanced exhaust manifold 200 of FIG. 2, wherein exhaust gasses exiting the output port 206 of the main body 208 pass through an output duct in the form of a second funnel 620. The second funnel 620 has a second funnel input port that matches the output port 206 of the main body 208. The second funnel 620 also has a second funnel output port 606 whose cross-sectional area is less than the cross-sectional area of the output port 206 of the main body 208. The second funnel 620 also implements a 45 degree turn between the second funnel input port and the second funnel output port 606. The second-variation vortex-enhanced exhaust manifold 600 was analyzed in an attempt to determine the extent to which the 90 degree turn of the first funnel 520 (FIG. 5) effects the fluid dynamics of the first-variation vortex-enhanced exhaust manifold 500.
As stated above, according to the CFD Analysis, the peak pressures at the exhaust duct input ports 204 of the first-variation vortex-enhanced exhaust manifold 500 average around 3 000 Pa. In contrast, the peak pressures at the exhaust duct input ports 204 of the second-variation vortex-enhanced exhaust manifold 600 average around 2 500 Pa.
FIG. 7 illustrates an end view of a section of a main body 708 of a third-variation vortex-enhanced exhaust manifold with an exhaust duct 702 passing through a wall 710 of the main body 708 to terminate in the interior of the main body 708. The exhaust duct 702 has an input port 704 and an output port 703. Like the exhaust duct 302 of FIG. 3, the exhaust duct 702 of FIG. 7 has a longitudinal axis offset from the longitudinal axis of the main body 708. However, unlike the exhaust duct 302 of FIG. 3, which has a consistent circular cross-sectional area throughout its length, the exhaust duct 702 of FIG. 7 tapers such that the circular cross-sectional area of the output port 703 is less than the circular cross-sectional area of the input port 704. For the CFD Analysis, the diameter of the exhaust duct 702 was reduced from 5.08 cm (2.00 inches) to 4.1275 cm (1.625 inches) over the final 7.62 cm (3 inches) of the exhaust duct 702. The analysis was performed using a third-variation vortex-enhanced exhaust manifold similar to the vortex-enhanced exhaust manifold 200 of FIG. 2, with exhaust ducts following the design of the exhaust duct 702 replacing the exhaust ducts 202.
As will be appreciated by a person of ordinary skill in the art of fluid dynamics, the taper in the exhaust duct 702 is likely to increase the velocity of the exhaust gasses flowing through the output port of the exhaust duct 702. The Applicant anticipated that the increase in the velocity of the exhaust gasses flowing through the output port would increase the velocity of the exhaust gasses swirling in a vortex in the main body 708. The expectation was that the increase in the velocity of the exhaust gasses swirling in the vortex would further enhance the depth of the region of low pressure and enhancing the pulling, encouraging, or drawing out of the exhaust gasses from the exhaust duct output port into the main body 708 of the third-variation vortex-enhanced exhaust manifold.
As stated above, according to the CFD Analysis, the peak pressures at the exhaust duct input ports 204 of the vortex-enhanced exhaust manifold 200 of FIG. 2 average around 1 500 Pa. In contrast, the peak pressures at the exhaust duct input ports of the third-variation vortex-enhanced exhaust manifold average around 5 000 Pa.
FIG. 8 illustrates a perspective view of an exhaust duct 802 having an input port 804 and an output port 803. The exhaust duct 802 tapers such that the cross-sectional area of the output port 803 is less than the cross-sectional area of the input port 804. Furthermore, the shape of the output port 803 of the exhaust duct 802 is given a gibbous shape. A gibbous shape is limited by a) a semicircle and b) a half ellipse whose major axis coincides with, and equals in length, the diameter defining the ends of the semicircle. When in position in a main body, the semicircular portion of the output port is located closest to the wall of the main body.
For the CFD Analysis, the cross-sectional area of the output port 803 of the exhaust duct 802 was maintained constant. The analysis was performed using a fourth-variation vortex-enhanced exhaust manifold similar to the vortex-enhanced exhaust manifold 200 of FIG. 2, with exhaust ducts following the design of the exhaust duct 802 replacing the exhaust ducts 202.
Notably, due to the changed of shape (no change in cross-section), there is a greater distance between the outlet port of the exhaust duct 702 of FIG. 7 and the adjacent wall 710 of the main body 708 than is present between the outlet port 303 of the exhaust duct 302 of FIG. 3 and the adjacent wall 310 of the main body 308.
The design of the output port 803 of the exhaust duct 802 is intended to gain any advantages available from an increased velocity given to the exhaust gasses by the reduced cross-sectional area of the output port (like the exhaust duct 702 of FIG. 7) while maintaining proximity of the output port 803 to the wall of the main body.
As stated above, according to the CFD Analysis, the peak pressures at the exhaust duct input ports 204 of the vortex-enhanced exhaust manifold 200 of FIG. 2 average around 1 500 Pa. In contrast, the peak pressures at the exhaust duct input ports of the fourth-variation vortex-enhanced exhaust manifold average around 4 000 Pa.
FIG. 9 illustrates a perspective view of an exhaust duct 902 having an output port 903 and input port 904. The exhaust duct 902 tapers in part and widens in part in such a manner that the cross-sectional area of the output port 903 is the same than the cross-sectional area of the input port 904. Furthermore, the shape of the output port 903 of the exhaust duct 902 of FIG. 9 is similar to the shape of the output port 803 of the exhaust duct 802 of FIG. 8.
The CFD Analysis was performed using a fifth-variation vortex-enhanced exhaust manifold similar to the vortex-enhanced exhaust manifold 200 of FIG. 2, with exhaust ducts following the design of the exhaust duct 902 replacing the exhaust ducts 202.
As stated above, according to the CFD Analysis, the peak pressures at the exhaust duct input ports 204 of the vortex-enhanced exhaust manifold 200 of FIG. 2 average around 1 500 Pa. In contrast, the peak pressures at the exhaust duct input ports of the fifth-variation vortex-enhanced exhaust manifold average around 3 000 Pa.
FIG. 10 illustrates, in perspective view, a sixth-variation vortex-enhanced exhaust manifold 1000 having wall 1010 defining a cylindrical main body 1008 that is adapted to receive a single exhaust duct 1002. Rather than outputting exhaust gasses via the output port 206 positioned at the open end of the main body 208 of the vortex-enhanced exhaust manifold 200 of FIG. 2, the sixth-variation vortex-enhanced exhaust manifold 1000 is adapted to output exhaust gasses via and an output duct 1022. As illustrated in FIG. 10 and FIG. 11, which illustrates a side view of sixth-variation vortex-enhanced exhaust manifold 1000, the output duct 1022 attaches to the wall 1010 of the main body 1008 at an aperture in the main body 1008.
In operation, any vortex of exhaust gasses in the main body 1008 of the sixth-variation vortex-enhanced exhaust manifold 1000 of FIGS. 10 and 11 will consist only of exhaust gasses from the single exhaust duct 1002. Notably, any vortex of exhaust gasses in the main body 208 of the vortex-enhanced exhaust manifold 200 of FIG. 2 will consist of exhaust gasses from three exhaust ducts 202.
A region of low pressure at the exhaust duct output port that is created by the vortex of exhaust gasses and that may act to pull, encourage, or draw the exhaust gasses from the exhaust duct into the interior of the main body of the exhaust manifold, thereby reducing pressure at the input port of the exhaust duct, has been discussed previously. The Applicants recognize that the volume of exhaust gasses available to form a vortex in the sixth-variation vortex-enhanced exhaust manifold 1000 of FIGS. 10 and 11 is one third of the volume of exhaust gasses available to form a vortex in the vortex-enhanced exhaust manifold 200 of FIG. 2.
According to the CFD Analysis, the peak pressures at the exhaust duct input port of the sixth-variation vortex-enhanced exhaust manifold average around 3 300 Pa.
FIG. 12 illustrates, in perspective view, a seventh-variation vortex-enhanced exhaust manifold 1200 having wall 1210 defining a cylindrical main body 1208 that is adapted to receive a single exhaust duct 1202. Like the sixth-variation vortex-enhanced exhaust manifold 1000 of FIGS. 10 and 11, the seventh-variation vortex-enhanced exhaust manifold 1200 is adapted to output exhaust gasses via and an output duct 1222. As illustrated in FIG. 12 and FIG. 13, which illustrates a side view of the seventh-variation vortex-enhanced exhaust manifold 1200, the output duct 1222 attaches to the wall 1210 of the main body 1208 at an aperture in the main body 1208. The aperture in the main body 1208 is displaced from the exhaust duct 1202 along the longitudinal axis of the main body 1208.
The position of the aperture of the seventh-variation vortex-enhanced exhaust manifold 1200 of FIGS. 12 and 13 is distinct from the position of the aperture of the sixth-variation vortex-enhanced exhaust manifold 1000 of FIGS. 10 and 11. In particular, the aperture of the sixth-variation vortex-enhanced exhaust manifold 1000 of FIGS. 10 and 11 is positioned approximately diametrically opposite (180 degrees away) from a point on the wall 1010 of the main body 1008 that is adjacent to the output port 1103 of the exhaust duct 1002. In contrast, the aperture of the seventh-variation vortex-enhanced exhaust manifold 1200 of FIGS. 12 and 13 is positioned approximately adjacent to (or, approximately 360 degrees away from) a point on the wall 1210 of the main body 1208 that is adjacent to the output port 1303 of the exhaust duct 1202.
According to the CFD Analysis, the peak pressures at the exhaust duct input port of the seventh-variation vortex-enhanced exhaust manifold average around 2 700 Pa.
Advantageously, it may be found that an internal combustion engine that employs a vortex-enhanced exhaust manifold according to aspects of what has been described hereinbefore will achieve higher efficiency engine performance than an internal combustion engine that employs a conventional exhaust manifold. The higher efficiency may result in either higher Horsepower or lower fuel consumption.
The above-described embodiments of the present application are intended to be examples only. Alterations, modifications and variations may be effected to the particular embodiments by those skilled in the art without departing from the scope of the application, which is defined by the claims appended hereto.

Claims

1. An exhaust manifold for handling exhaust from an internal combustion engine, said exhaust manifold comprising:

an empty main body defined by a generally cylindrical wall, an aperture and a main body longitudinal axis; and

an exhaust duct configured to pass through said wall to terminate inside said main body, said exhaust duct having an exhaust duct longitudinal axis that is offset from said main body longitudinal axis so that exhaust gasses introduced from said exhaust duct into said main body form a vortex as said gasses progress toward said open end of said main body.

2. The exhaust manifold of claim 1 wherein said main body has a generally circular closed end and said aperture is an open end opposite said closed end.

3. The exhaust manifold of claim 1 wherein said main body is closed at each end and said aperture is in said cylindrical wall.

4. The exhaust manifold of claim 3 wherein said aperture leads to an output duct, said output duct having an output duct longitudinal axis.

5. The exhaust manifold of claim 4 wherein said output duct longitudinal axis is in a plane with said exhaust duct longitudinal axis.

6. The exhaust manifold of claim 4 wherein said output duct longitudinal axis is offset from said exhaust duct longitudinal axis along said main body longitudinal axis.

7. The exhaust manifold of claim 3 wherein said aperture is positioned in said wall diametrically opposite from a point on said wall that is adjacent to an output port of said exhaust duct.

8. The exhaust manifold of claim 3 wherein said aperture is positioned in said wall adjacent a point on said wall that is adjacent to an output port of said exhaust duct.

9. The exhaust manifold of claim 1 wherein said exhaust duct has an input port for receiving exhaust gasses from a cylinder of said internal combustion engine and an output port through which said exhaust gasses enter said main body.

10. The exhaust manifold of claim 9 wherein said exhaust duct includes a taper such that said output port has a smaller cross-sectional area than said input port.

11. The exhaust manifold of claim 9 wherein said output port of said exhaust duct has a circular shape.

12. The exhaust manifold of claim 9 wherein said output port of said exhaust duct has a gibbous shape.