Information
-
Patent Grant
-
6691686
-
Patent Number
6,691,686
-
Date Filed
Friday, December 28, 200122 years ago
-
Date Issued
Tuesday, February 17, 200420 years ago
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Inventors
-
Original Assignees
-
Examiners
- Yuen; Henry C.
- Ali; Hyder
Agents
- Brinks Hofer Gilson & Lione
-
CPC
-
US Classifications
Field of Search
US
- 123 56817
- 123 18421
- 123 18424
- 123 18434
- 123 18435
- 123 18436
- 123 18442
- 123 18443
- 123 18444
- 123 18447
- 123 18448
- 123 18449
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International Classifications
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Abstract
Intake manifolds for an internal combustion engine and methods of using the same are disclosed. The intake manifolds accommodate the introduction of exhaust gas that has been recirculated from the main exhaust gas stream. The exhaust gas can be introduced into the intake manifold through aerodynamically shaped members that are located inside the manifold. Alternatively, the exhaust gas can be introduced into the manifold at or near the intersection of the primary runners and the plena, or the exhaust gas can be introduced into a mixing chamber located between the primary runners and the plena.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to a means for recirculating exhaust gas through an engine.
Exhaust gas is commonly recirculated through an internal combustion engine in order to improve the exhaust gas quality and fuel efficiency of the engine. In general, a portion of the exhaust from the engine is siphoned off the main exhaust stream downstream of the engine and re-routed to a location upstream of the engine where it is mixed with the fresh air supply. The mixture of fresh air and the recirculated exhaust gas is then supplied to the engine. The degree to which fuel efficiency and exhaust gas quality of the engine are improved depends on, among other things, the location where the exhaust gas is injected into the fresh air stream and the manner in which it is injected.
One possible location for introducing the exhaust gas into the fresh air stream is to inject the exhaust gas at some point on the intake manifold. The are myriad possible locations on an intake manifold where the exhaust gas can be injected, and the resultant improvements in fuel efficiency and exhaust gas quality are equally varied. The flow conditions vary greatly throughout an intake manifold and significantly affect the degree to which the exhaust gas is mixed with the fresh air coming into the system. If the exhaust gas and the fresh air are not thoroughly mixed, the full benefits of exhaust gas recirculation (EGR) are not realized. The present invention provides an improved system for injecting exhaust gas into an intake manifold that seeks to improve the mixing of recirculated exhaust gas and fresh air, and maximize the benefits of EGR.
BRIEF SUMMARY OF THE INVENTION
Intake manifolds for an internal combustion engine are provided. In a first embodiment the intake manifold comprises an air inlet; a plenum, the plenum being in fluid communication with the air inlet; at least one primary runner, the at least one primary runner being attached to and in fluid communication with the plenum; and an EGR inlet. The EGR inlet is located near the intersection of the at least one primary runner and the plenum. In a second embodiment, the intake manifold comprises an air inlet; a plenum in fluid communication with the air inlet; at least one primary runner, the at least one primary runner being in fluid communication with the plenum; a flange, the flange having a front side and a back side, wherein the front side of the flange faces the air inlet; and an EGR inlet. The EGR inlet is located on the flange. In a third embodiment, an intake manifold comprises an air inlet; a plenum, the plenum being in fluid communication with the air inlet; a mixing reservoir, the mixing reservoir being in fluid communication with the plenum; a plurality of primary runners, the plurality of primary runners being in fluid communication with the mixing reservoir; and an EGR inlet. The EGR inlet is located in the plenum. In a fourth embodiment, an intake manifold comprises an air inlet; a plenum; a secondary runner, the air inlet being in fluid communication with the plenum via the secondary runner; at least one primary runner, the at least one primary runner being in fluid communication with the plenum; a flow strut, the flow strut being located in the secondary runner; and an EGR inlet. The EGR inlet is located on the strut.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
FIG. 1
is a top view of a first embodiment of an intake manifold according to the present invention.
FIG. 2
is a side view of a first embodiment of the intake manifold of the present invention, wherein the wall of the plenum has been cut away.
FIG. 3
is a top view of a second embodiment of an intake manifold according to the present invention.
FIG. 4
is a perspective view of a second embodiment of the intake manifold according to the present invention, wherein the top portion of the secondary runners has been cut away.
FIG. 5
is a top view of a third embodiment of an intake manifold according to the present invention.
FIG. 6
is a top view of a fourth embodiment of an intake manifold according to the present invention, wherein the top portion of the secondary runners has been cut away.
FIG. 7
is a perspective view of a fourth embodiment of an intake manifold according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention may be applied to an intake manifold for any type or configuration of internal combustion engine. The exemplary embodiments shown in the drawings and described below are directed to a double-plenum intake manifold for an inline six-cylinder engine. The present invention could also be applied to, for example and without limitation, a single plenum intake manifold, an intake manifold for an engine with more or less than six cylinders, or an intake manifold for a V-type engine. The double-plenum intake manifold for an inline six-cylinder engine described herein is only illustrative of the claimed invention, and does not limit application of the present invention to manifolds for different engine configurations.
Any method of conveying exhaust gas from the main exhaust stream to the intake manifold may be used with the present invention. The method of withdrawing a portion of exhaust gas from the main exhaust stream and routing it back to the intake manifold does not limit the scope or application of the present invention.
The intake manifold of the present invention can be made of any material that is suitable for use with an internal combustion engine. The intake manifold is most preferably made of cast aluminum. The intake manifold of the present invention likewise can be made according to any method that is suitable for making an intake manifold for use with an internal combustion engine. The composition and manufacture of the intake manifold of the preferred embodiment do not limit the scope or application of the present invention.
FIGS. 1 and 2
show an intake manifold according to a first embodiment of the present invention. The intake manifold
10
includes a pair of secondary runners
11
that connect the air inlet
12
to the plena
13
. The air inlet
12
is thus in fluid communication with the plena
13
. A series of primary runners
14
connect the plena
13
to the cylinder heads (not shown) positioned approximately beneath the terminal end of each primary runner
14
. Each plenum
13
collects the air and distributes it to the appropriate primary runner
14
as air is needed by the corresponding cylinder. EGR inlets
15
are located at or near the intersection of the primary runners
14
with the plena
13
. The embodiment shown in
FIG. 2
shows two EGR inlets
15
per primary runner
14
. Alternatively, there could be only one EGR inlet
15
per primary runner, or more than two. In a preferred embodiment, the EGR inlets
15
are elliptical and have a major that is approximately 0.3 inches in diameter. Exhaust gas is fed through EGR inlets
15
by EGR tubes (not shown). EGR tubes supply the exhaust gas that has been siphoned off the main exhaust stream downstream of the engine.
In operation, air is fed to the intake manifold embodied in
FIGS. 1 and 2
through inlet
12
. The amount of airflow into the intake manifold is controlled by a throttle body (not shown) attached to the inlet
12
. After entering the inlet
12
, the air is routed through the two secondary runners
11
to the plena
13
. The air is held in the plena
13
until the air is needed by one of cylinders. When air is needed by one of the cylinders, the air is drawn from the plenum
13
into the corresponding primary runner
14
. The airflow from the plenum
13
into the primary runner
14
creates an area of low pressure near the intersection of the primary runner
14
with the plenum
13
. Exhaust gas is injected into the area of low pressure through EGR inlet
15
. The exhaust gas and fresh air mix in the area of low pressure and the resultant mixture flows through the primary runner
14
into the corresponding cylinder.
FIGS. 3 and 4
show an intake manifold according to a second embodiment of the present invention. The intake manifold
10
includes a pair of secondary runners
11
that connect the air inlet
12
to the plena
13
. The air inlet
12
is thus in fluid communication with the plena
13
. A series of primary runners
14
connect the plena
13
to the cylinder heads (not shown). Each plenum
13
collects the gas to be fed to the cylinders and distributes it to the cylinders via primary runners
14
. Positined within each of the secondary runners
11
is a flange
20
. As shown, each flange
20
is located opposite from the air inlet
12
and spaced from the back wall of the secondary runners
11
. Each flange
20
is an aerodynamic member and has a shape that causes as little disruption to the fluid flow as possible. In a preferred embodiment, flange
20
has a concave side
16
and a convex side
17
, wherein the convex side
17
faces the air inlet
12
. More preferably, the flange
20
extends the full height of the secondary runners
11
. In the preferred embodiment of
FIGS. 3 and 4
, the concave side faces the back wall of the secondary runners
11
. It can be appreciated, however, that in embodiments where there is a straight run between the air inlet
12
and the plenum
13
, the concave side faces downstream rather than the back wall of the secondary runners
11
. The important aspect of this preferred embodiment is that the convex side faces the air inlet
12
. Preferably, the flange
20
has a radius of curvature of
10
inches and is 1 inch long. In a preferred embodiment, the flange
20
is made of stainless and is attached in the secondary runners
11
by an isolation fitting. Alternatively, the flange
20
can be cast with and constructed of the same material as the rest of the intake manifold. Flange
20
includes one or more EGR inlets
15
. The EGR inlets are preferably 0.1 inch in diameter. The preferred embodiment shown in
FIG. 4
includes four EGR inlets, however, there may be more or less than four EGR inlets. Preferably the exhaust gas is fed into flange
20
and through EGR inlets
15
by EGR tube(s) that enter the manifold from underneath the flange
20
.
In operation, air is fed to the intake manifold embodied in
FIGS. 3 and 4
through inlet
12
. The amount of air fed to the intake manifold is controlled by a throttle body (not shown) attached to the inlet
12
. After entering the intake manifold through inlet
12
the air flows around flange
20
. Exhaust gas is injected into the manifold through EGR inlets
15
. The exhaust gas and air are mixed together and flow through the secondary runners
11
to the plena
13
. Preferably, as the cylinders of the engine need air, the mixture of exhaust gas and air is drawn from the plena
13
and is supplied to the appropriate cylinder through primary runners
14
.
FIG. 5
shows an intake manifold according to a third embodiment of the invention. The intake manifold
10
includes a pair of secondary runners
11
that connect the air inlet
12
to the plena
13
. The air inlet
12
is thus in fluid communication with the plena
13
. A mixing chamber
30
is attached to and in fluid communication with each plenum
13
. Primary runners
14
lead from the mixing chambers
30
to the cylinder heads (not shown). An EGR inlet
15
is located in the wall of each plenum
13
.
In operation, air is fed to the intake manifold embodied in FIG.
5
through inlet
12
. The amount of airflow into the intake manifold is controlled by a throttle body (not shown) attached to the inlet
12
. After entering the inlet
12
the air is routed through the two secondary runners
11
to the plena
13
. Once in the plena
13
, the air expands to fill mixing chamber
30
. The expansion of the air from the plenum
13
into mixing chamber
30
creates an area of low pressure. Exhaust gas is injected into the area of low pressure through EGR inlet
15
. The exhaust and fresh air mix in the mixing chamber
30
. The mixture of exhaust gas and fresh air is then drawn from the mixing chamber
13
through primary runners
14
and supplied to the appropriate cylinder.
FIGS. 6 and 7
show an intake manifold according to a fourth embodiment of the present invention. The intake manifold
10
includes a pair of secondary runners
11
that connect the air inlet
12
to the plena
13
. Each plenum
13
is thus in fluid connection with the air inlet
12
. The plena
13
serve to collect and supply air to the primary runners
14
. A series of primary runners
14
connect the plena
13
to the cylinder heads (not shown). In the secondary runners
11
are flow struts
40
. Flow struts
40
preferably comprise curved, elongated structures that are centrally located in secondary runners
14
. Preferably, flow struts
40
are aerodynamically shaped so as to cause as little disruption to the air flow as possible. In a preferred embodiment, flow struts
40
have a tear-shaped cross-section, with a concave side
42
and a convex side
41
. Preferably, flow struts
40
extend the full height of the secondary runner
11
. In the preferred embodiment, flow struts
40
are made of stainless steel and are attached in the intake manifold by an isolation fitting. Alternatively, flow struts
40
can be cast with, and constructed of the same material as, the rest of the intake manifold. Flow struts
40
include one or more EGR inlets
15
. The EGR inlets
15
are preferably 0.1 inch in diameter. The preferred embodiment shown in
FIG. 7
includes two EGR inlets per flow strut
40
, however, there may be more or less than two EGR inlets. Preferably the exhaust gas is fed into flow strut
40
and through EGR inlets
15
by EGR tube(s) that enter the manifold from underneath flow strut
40
.
In operation, air is fed to the intake manifold embodied in
FIGS. 6 and 7
through inlet
12
. The amount of airflow into the intake manifold is controlled by a throttle body (not shown) attached to the inlet
12
. After entering the inlet
12
the air is routed through the two secondary runners
11
. As the air flows through secondary runners
11
, the air flows around flow struts
40
and into the plena
13
. Exhaust gas is injected into the manifold through EGR inlets
15
. The exhaust gas and fresh air are mixed in the secondary runners
11
and flow to the plena
13
. The mixture of exhaust gas and fresh air is drawn from the plena
13
through primary runners
14
and supplied to the appropriate cylinder.
An advantage of the embodiments of the first, third, and fourth embodiments is that the exhaust gas is introduced into the intake manifold at a location that is remote from the air inlet
12
. One problem associated with EGR systems is that the heat from the exhaust gas has the potential to damage sensitive electronic components, such as throttle bodies, on or near the air inlet for the intake manifold. It is desirable to locate these electronics near the inlet because the air flowing into the manifold through the inlet acts as a heat sink and cools the electronics. If exhaust gas is injected into the intake manifold near the air inlet, the heat from the exhaust gas has the potential to not only counteract the heat sink effect of the incoming fresh air, but also to raise the temperature of the electronic components to an unacceptable level. As a result, there is a possibility that the electronic components can be damaged. Because the intake manifolds of the first, third, and fourth embodiments introduce the exhaust gas away from the inlet, the inlet air can effectively cool the electronics and the heat of the exhaust gas does not damage the electronics.
The design of the EGR tube used to inject exhaust gas into the intake manifold does not limit the scope or application of this invention. By way of example, an EGR tube for use with the first or third embodiment can be an open-ended tube that is inserted through the EGR inlet. In a preferred embodiment, the end of the EGR tube is closed and there are several holes around the perimeter of the tube near the closed-end. This closed-end design aids distribution of the exhaust gas and encourages more turbulent and thorough mixing of the exhaust gas with the fresh air in the manifold.
Of course, it should be understood that a wide range of changes and modifications can be made to the embodiments described above and depicted in the drawings. It is intended, therefore, that the foregoing description illustrates rather than limits this invention, and that it is the following claims, including all equivalents, that define this invention.
Claims
- 1. An intake manifold for an internal combustion engine, the manifold comprising:a. an air inlet; b. a plenum, the plenum being in fluid communication with the air inlet; c. a plurality of primary runners, the primary runners being attached to and in fluid communication with the plenum; and, d. an EGR inlet located adjacent each intersection of a primary runner and the plenum.
- 2. The intake manifold of claim 1 further comprising a secondary runner located between and in fluid communication with the air inlet and the plenum.
- 3. An intake manifold for an internal combustion engine, the manifold comprising:a. an air inlet; b. a plenum, the plenum being in fluid communication with the air inlet; c. a plurality of primary runners, the primary runners being attached to and in fluid communication with the plenum; and, d. an EGR inlet located at each intersection of a primary runner and the plenum.
- 4. An intake manifold for an internal combustion engine, the manifold comprising:a. an air inlet; b. at least two secondary runners, each secondary runner being adjacent to and in fluid communication with the air inlet; c. at least two plena, each plenum being adjacent to and in fluid communication with one of the secondary runners; d. at least two primary runners attached to and in fluid communication with each plenum; and e. an EGR inlet located adjacent each intersection of a primary runner and a plenum.
US Referenced Citations (13)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0727572 |
Aug 1996 |
EP |
2002 89376 |
Mar 2002 |
JP |