Internal-combustion engines – Intake manifold – Passage to crankcase
Reexamination Certificate
1999-12-29
2002-03-19
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Intake manifold
Passage to crankcase
C123S184340, C123S184420, C123S184470
Reexamination Certificate
active
06357411
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for internal combustion engines. More specifically, the present invention relates to an intake device for internal combustion engines that allows the lengths of branching paths to be uniform, thereby improving output performance of the internal combustion engine. Additionally, the present invention relates to an intake device for internal combustion engines having smooth branching paths, thereby reducing intake resistance. The present invention relates to an intake device for internal combustion engines having a more compact and lightweight intake manifold, thereby reducing fuel consumption and improving power performance. Finally, the present invention relates to an intake device for internal combustion engines having a more compact internal combustion engine, thereby improving ease of mounting in an automobile and making the automobile lighter.
In conventional internal combustion engines mounted in cars, an intake device is disposed to guide intake gas into a plurality of gas columns. In this conventional intake device, there is an intake manifold that guides the intake gas to the gas columns. A throttle body adjusts the air intake.
Referring to
FIG. 16
, an internal combustion engine
202
, mounted in an automobile (not shown), includes a cylinder block
204
having an oil pan
210
. A cylinder head
206
is covered by a head cover
208
. In this conventional internal combustion engine
202
, a plurality of gas columns, e.g., four gas columns numbers 1-4 (not shown in the figure), are arranged in a row. An intake device
212
is positioned at cylinder head
206
.
Air intake device
212
includes a throttle body
214
and an intake manifold
216
. Throttle body
214
adjusts air intake using an internal throttle valve (not shown in the figure). Intake manifold
216
guides intake gas to the gas columns.
Referring to
FIG. 17
, an attachment flange
218
attaches to cylinder head
206
. First through fourth branching pipes
220
-
1
-
220
-
4
correspond to the first through fourth gas columns numbers 1-4. A surge tank
222
restricts intake gas ripples.
Surge tank
222
is positioned at a gas column row center C along a gas column row direction D formed by the four gas columns numbers 1-4 of internal combustion engine
202
. The ends of first through fourth branching pipes
220
-
1
-
220
-
4
connect to attachment flange
218
. The other ends of first through fourth branching pipes
220
-
1
-
220
-
4
connect to surge tank
222
.
With this conventional intake manifold
216
, first and second branching pipes
220
-
1
and
220
-
2
connect to attachment flange
218
on one side of gas column center C along gas column row direction D. The other end of first and second branching pipes
220
-
1
and
220
-
2
connect to a side wall
224
of surge tank
222
facing one side of gas column direction D. Also, in intake manifold
216
, third and fourth branching pipes
220
-
1
and
220
-
2
connect to attachment flange
218
on the other side of gas column center C along gas column row direction D. The other end of third and fourth branching pipes
220
-
3
and
220
-
4
connect to an opposite side wall
226
of surge tank
222
, facing the other side of gas column direction D.
Thus, with conventional intake manifold
216
, first through fourth branching pipes
220
-
1
-
220
-
4
are disposed symmetrically around gas column row center C, connecting attachment flange
218
with surge tank
222
. This allows first through fourth branching paths
228
-
1
-
228
-
4
to have uniform lengths.
This type of intake device for internal combustion engine is disclosed in Japanese laid- open patent publication number 5-180091, Japanese utility model publication number 2549543, and Japanese laid-open utility model publication number 5-21161.
In the disclosure in Japanese laid-open patent publication number 5-180091, the branching pipes are all grouped together and connected lengthwise to the surge tank. A contact section is disposed where the intake manifold attachment flange abuts the main engine unit. A chamber is disposed below the intake path of the contact section. A partitioning wall is disposed to partition the chamber into upper and lower divisions, and a communicating section is disposed to connect the two divisions. Communicating paths are disposed to connect the intake paths of each of the gas columns to one of the divisions, and an EGR path is disposed to send exhaust gas to the other chamber.
Referring to
FIG. 15
, the disclosure in Japanese utility model publication number 2549543 is roughly similar to what is shown in the figure. The path width of the curving intake pipes connected to the surge tank are roughly uniform. The cross-sections thereof are formed so that the curvature at the outside of the curve is greater than the curvature at the inside of the curve.
The cross-section shapes of the curving branches of the intake manifold are formed as ellipses so that their centroids are positioned closer toward the outside of the curves rather than at the centers of the intake pipes.
However, with the conventional intake devices of internal combustion engines, there are cases when the surge tank cannot be disposed at the center of the gas column row due to restrictions imposed by how the internal combustion engine is mounted in the automobile and the like.
Referring to
FIG. 18
, for example, in intake manifold
216
of intake device
212
a center C
1
of surge tank
222
is offset by a distance M toward a third gas column #3 toward one side of gas column row direction D.
With manifold
216
having surge tank
222
offset in this manner, first through fourth branching pipes
220
-
1
through
220
-
4
are disposed so that the path lengths of first and second branching paths
228
-
1
and
228
-
2
of first and second branching pipes
220
-
1
and
220
-
2
are longer than the path lengths of third and fourth branching paths
228
-
3
and
228
-
4
of third and fourth branching pipes
220
-
3
and
220
-
4
.
Thus, with this conventional intake device
212
, the path lengths of first through fourth branching paths
228
-
1
through
228
-
4
cannot be made uniform. The non-uniformity results in variations in intake air flow through first through fourth gas columns #1 through #4. This reduces the output performance of internal combustion engine
202
.
The path lengths of first through fourth branching paths
228
-
1
through
228
-
4
can be made uniform by having first and second branching pipes
220
-
1
and
220
-
2
formed with a larger curvature, resulting in a tighter curve, compared to third and fourth branching pipes
220
-
3
and
220
-
4
.
Referring to
FIGS. 19 and 20
, compared to branching pipe
220
, as shown in
FIG. 19
, formed with a small curvature resulting in a more gradual curve, branching pipe
220
, as shown in
FIG. 20
, is formed with a larger curvature, resulting in a tighter curve. This leads to increased intake resistance due to the tighter curve in branching path
228
. Thus, the output performance of the internal combustion engine is reduced.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide an intake device for an internal combustion engine which overcome the foregoing problems
It is a further object of the present invention to provide an intake device for an internal combustion engine which allows the length of the branching paths to be uniform, thereby improving output performance.
It is another object of the present invention to provide an intake device for an internal combustion engine which has smooth branching parts, thereby reducing intake resistance.
It is yet a further object of the present invention to provide an intake device for an internal combustion engine which has a more compact and lightweight design, thereby reducing fuel consumption, improving power performance, improving the ease of mounting in an automobile, and making the automobile lighter.
Briefly stated, the present invention provides a branching pipes
Huynh Hai
Morrison Law Firm
Suzuki Motor Corporation
Wolfe Willis R.
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