VORTEX-ENHANCED EXHAUST MANIFOLD
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.
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 INVENTIONWithin 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.
SUMMARYExhaust 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.
Reference will now be made to the drawings, which show by way of example, embodiments of the invention, and in which:
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.
As the end of the main body 208 that is opposite the output port 206 (not shown in
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 (
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.
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.
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.
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
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
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
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
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
The CFD Analysis was performed using a fifth-variation vortex-enhanced exhaust manifold similar to the vortex-enhanced exhaust manifold 200 of
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
In operation, any vortex of exhaust gasses in the main body 1008 of the sixth-variation vortex-enhanced exhaust manifold 1000 of
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
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.
The position of the aperture of the seventh-variation vortex-enhanced exhaust manifold 1200 of
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.
Type: Application
Filed: Jul 24, 2008
Publication Date: Jan 28, 2010
Inventor: Edward CARR (Port Carling)
Application Number: 12/178,892
International Classification: F01N 7/00 (20060101);