USO0RE42056E
(19) United States (12) Reissued Patent
(10) Patent Number:
Akazaki et a]. (54)
(45) Date of Reissued Patent:
EXHAUST GAS PURIFICATION SYSTEM OF
EP
INTERNAL COMBUSTION ENGINE
(75)
US RE42,056 E
0 719 926
Jan. 25, 2011
7/1996 .
(Contlnued)
Inventors: Shusuke Akazaki, Wako (JP); Kohei
Hanada, Wako (JP); Yuji Yasui, Wako (JP); Tadashi Satoh, Wako (JP); Takashi Haga, Wako (JP)
OTHER PUBLICATIONS
Patent Abstracts of Japan, vol. 018, No. 607 (Mil 707), Nov. 18, 1994 & JP 06*229324 (Nissan Motor Co. Ltd), Aug. 16, 1994.
(73) Assignee: Honda Giken Kogyo Kabushiki
(Continued)
Kaisha, Tokyo (JP)
Primary ExamineriTu M Nguyen
(21) App1.N0.: 09/945,835
(74) Attorney, Agent, or FirmiArent Fox LLP
(22) Filed:
(57)
Sep. 5, 2001
A system for purifying exhaust gas generated by an internal combustion engine including a bypass branching out from the exhaust pipe downstream of a catalyst and merging to the exhaust pipe, an adsorber installed in the bypass, a bypass
Related US. Patent Documents
Reissue of:
(64)
Patent No.:
Appl. No.:
5,946,906 Sep. 7, 1999 08/975,101
Filed:
Nov. 20, 1997
Issued:
(30)
ABSTRACT
valve member Which closes the bypass, and an EGR conduit connected to the bypass at one end and connected to the air intake system for recirculating the exhaust gas to the air
Foreign Application Priority Data
(52)
US. Cl. ............................ .. 60/278; 60/284; 60/288;
(58)
Field of Classi?cation Search .................. .. 60/274,
intake system. The bypass valve member is opened for a period after engine startup to introduce the exhaust gas such that the adsorber installed in the bypass adsorbs the unburnt HC component in the exhaust gas. The adsorber adsorbs the HC component When the exhaust temperature rises and the adsorbed component is recirculated to the air intake system through the EGR conduit. 1n the system, the bypass valve is provided at or close to the branching point in the exhaust pipe and a chamber is provided close to the branching point
60/276, 277, 278, 279, 284, 285, 288, 297, 60/311, 287; 701/104
end in the chamber. The bypass valve member is combined
Nov. 20, 1996
(51)
(JP) ........................................... .. 8-324809
Int. C]. F02M 25/06
(2006.01) 60/297
See application ?le for complete search history. (56)
References Cited U.S. PATENT DOCUMENTS 3,699,683 A
* 10/1972
Touitellotte et a1. ......... .. 60/274
such that the conduit is connected to the bypass at the one With an exhaust pipe valve member as a combination valve
such that When the bypass valve member closes the bypass, the exhaust pipe valve member opens the exhaust pipe. With the arrangement, the system can effectively prevent the exhaust pipe from being clogged even When a valve for clos ing a bypass is stuck in the closed position. At the same time, the system can provide a relatively short EGR conduit for
(Continued) FOREIGN PATENT DOCUMENTS DE EP
43 28125 0 616115
2/1994 9/1994
recirculating unburnt HC component adsorbed from the adsorber and the adsorption and desorption are conducted
optimally. 11 Claims, 17 Drawing Sheets
US RE42,056 E Page 2
U.S. PATENT DOCUMENTS
JP JP
5,125,231 A
*
4-311618 04-365947 A
11/1992 12/1992
6/1992 Patil et a1. ................... .. 60/274
JP
5_171929
7/1993
5,207,734 A *
5/1993 Day et a1.
60/278
JP
0693846 A
4/1994
5,315,824 A
*
A A A A
* * * *
5/1994 2/1995 3/1996 6/1996 8/1996
Takeshima ................. .. 60/297
5,388,405 5,497,619 5,524,433 5,544,482
60/297 60/279 60/279 60/279
JP JP JP JP JP
693931 6401461 06_229324 A 07_26947 A 07_g3151 A
4/1994 4/1994 8/1994 1/1995 3/1995
5,589,143
12/1996
. . . .. 60/297
JP
8_71427
3/1996
Fujishita et a1. ............. .. Yamada et a1. .............. .. Adamczyk, Jr. et a1. ..... .. Matsumoto et a1. ......... ..
A
*
5,634,332 A
*
6/1997 Tanaka et a1.
Mori et a1.
......
5,655,362 A
*
8/1997 Kawajiri et a1. ............. .. 60/284
5,657,736 A
*
8/1997
60/288 OTHER PUBLICATIONS
Maki et a1. ................ .. 123/673
5,729,971 A * 5,758,490 A *
3/1998 Matsuno et a1 6/1998 Maki et a1.
60/276 60/285
5,76l,902 A *
6/1998 Usami et a1. ................ .. 60/288
Patent Abstracts Of Japan, V01. 095, NO. 005, Jun. 30, 1995 & JP 07*042538 (Fuji Heavy Ind- Ltd), Feb- 10, 1995 Patent Abstracts of Japan, V01. 016, N0. 173 (MA124O), Apr.
24, 1992 & JP 044017710 (Mazda Motor Corp), Jan. 22, FOREIGN PATENT DOCUMENTS 4-17710
l/l992
1992. * cited by examiner
US. Patent
NGF‘
Jan. 25, 2011
Sheet 1 0f 17
US RE42,056 E
US. Patent
Jan. 25, 2011
Sheet 3 0f 17
US RE42,056 E
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US. Patent
Jan. 25, 2011
Sheet 4 0f 17
US RE42,056 E
Fl6.4
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//
TRPV‘ON
TRPV-OFF
ks24
US. Patent
Jan. 25, 2011
Sheet 5 0f 17
US RE42,056 E
Fl6.5
40
60
80
I00
Tw ('C)
US. Patent
Jan. 25, 2011
Sheet 6 0f 17
US RE42,056 E
Fl6‘.6 From engine starting and low temperature (HC adsorption made)
FIG. 7 Normal temperature and without EGR (HC trapping mode)
F/6.8 Normal temperature and with EGR (HC purging mode)
' ' HC Adsarber
US. Patent
Jan. 25, 2011
Sheet 7 0f 17
US RE42,056 E
Fl 6. 9
MU
START
S100
S106
TRTD = TRTDAST
M
TRTD : TRTDLMT /
<
8110 2 _
8112 2
V : VRTDLMT
_\[_
mm (W
5118
TM < Tw < TW2 T
N
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5120 I
N P.S.Switch ON
—
5122 Y
N
TCAT : TCATRTDH/
—
s10 / 2 < r, S126 /5"4 Control iqnition?iming Control ignition timing TRTD = TRTDLMT under stortmq
in retard ~d|rect1on
1
)104 Start TRTD
CQHtfOl. ignition timing In ordmury manner I
(
EXlT
)
US. Patent
Jan. 25, 2011
Sheet 10 0f 17
US RE42,056 E
F I 6 . 12
Read ,Ne, Pb. Po. LACT
~ $200
Retrieve LCMD by Ne and Pb
~S202
l Retrieve KEGRMAP by Ne and Pb M15204
5208 5220
I
QACT/QCMD=0
\s222
KEGRMAP=KEGRMAPK 4 “5224 L
.5270
Retrieve QCMD by LCMD 0nd Pb/Po
Retrieve QACT by LACT and Pb/Pe
J S272 /
Steady-state EGR rate = I - KEGRMAP 45214
1 Net EGR rate = Steady-state EGR rate X (QACT/QCMD)
l
$276
Calculate KEGRN (
RETURN
\szla )
US. Patent
Jan. 25, 2011
Sheet 11 0f 17
US RE42,056 E
Fl 6. I3
QEGRN CALCULATION) Colcuiote coefficient KEGRN w 5300 KEGRN = i - net EGR rote
Store coefficient KEGRN in ring buffer \# S302 (buffer N0. = 0. i, 2. w n)
Retrieve delay time r by Ne and Pb (r = buffer No. )
\5304
Reed one from among stored coefficients
KEGRN by retrieved delay time r and correct TiM-F by coefficient KEGRN
RET
/S306
US. Patent
Jan. 25,2011
Sheet 12 or 17
US RE42,056 E
F 16. I4 KEGRN Current value
N0 0
I TDC earlier 2 TDCs earlier 3 TDCs earlier 4 ll
1 2 3 4
5
II
5
6
11
6
7
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7
E
8
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8
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9 10
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9 10
I1
1/
H
12
1
1'2
C C < C
E
g
; \1/ ‘
Fl6.l5 Pb
Ne
H
i n‘
US. Patent
6:12 mm
vm
Jan. 25,2011
Sheet 14 or 17
US RE42,056 E
US. Patent
Jan. 25, 2011
Sheet 15 0f 17
US RE42,056 E
US. Patent
2
.2 . ‘
Jan. 25, 2011
Sheet 16 0f 17
US RE42,056 E
US. Patent
Jan. 25, 2011
US RE42,056 E
Sheet 17 0f 17
F I G . 20
____l\ N
<
FTRPV — 1
Calculate {Tout 8412
/
@outzT0utLMTT>—Y—— S414 N
5402 I Read and odd Tout
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/ TRPV-ON
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EXIT
)
US RE42,056 E 1
2
EXHAUST GAS PURIFICATION SYSTEM OF INTERNAL COMBUSTION ENGINE
between the connection point of the bypass with the EGR conduit and the engine increases as the connection point is situated closer to the rear of the vehicle.
Matter enclosed in heavy brackets [ ] appears in the original patent but forms no part of this reissue speci?ca
Similar disadvantages are found in the other prior art sys
tems (disclosed in 5-171,929 and 6-101,461).
tion; matter printed in italics indicates the additions made by reissue.
SUMMARY OF THE INVENTION
An object of the invention is therefore to provide an exhaust gas puri?cation system of an internal combustion engine having an adsorber for adsorbing the unburnt HC
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to an exhaust gas puri?cation sys tem of an internal combustion engine for removing an unburnt HC component from the exhaust gas.
component in the exhaust gas generated by the engine, which can solve the drawbacks in the prior art systems, and
which can effectively prevent the exhaust pipe from becom ing clogged even if a valve for closing a bypass is stuck in
2. Description of the Related Art Internal combustion engines are ordinarily provided with
the closed position. A second object of the invention is therefore to provide an exhaust gas puri?cation system of an internal combustion engine having an adsorber for adsorbing the unburnt HC
a catalyst (a three-way catalytic converter) in the exhaust system which removes HC, NOx and CO components in the
exhaust gas generated by the engine. However, when the engine is cold started, for example, and the catalyst is not
20
activated, an unburnt HC component is immediately exhausted to the atmosphere. For that reason, there is proposed an exhaust gas puri?ca
tion system in Japanese Laid-Open Patent Application Hei 4(1992)-17,710. In the system, the exhaust pipe 5 is
component in the exhaust gas generated by the engine, which can provide a relatively short EGR conduit for recir culating an unburnt HC component adsorbed from the adsorber. A third object of the invention is to provide an exhaust gas
25
puri?cation system of an internal combustion engine having an adsorber for adsorbing the unburnt HC component in the
branched out at a location downstream of the catalysts 6, 7. The bypass 9 is provided with an adsorber 10 made of active
exhaust gas generated by the engine, in which adsorption and desorption are conducted optimally. This invention achieves this object by providing a system for purifying exhaust gas generated by an internal combus tion engine having an air intake system and an exhaust sys
carbon or activated charcoal and carried on two beds. The
bypass is again merged to the exhaust pipe 5 downstream of the adsorber. An Exhaust Gas Recirculation (EGR) conduit 15 is connected before the merging point where the bypass 9
tem which includes an exhaust pipe extending from an exhaust manifold of the engine and a catalyst installed in the
is located such that an unburnt HC component, when
adsorbed, is recirculated to the engine intake system through
exhaust pipe, the exhaust system exhausting gas generated by the engine to the atmosphere, including a bypass branch
the EGR conduit 15. A valve 14 is provided in the bypass 9 downstream thereof to open or close the bypass 9. Moreover, another valve 13 is provided in the exhaust pipe 5 to close
ing out from the exhaust pipe at a location downstream of the
the same so as to lead the exhaust gas to ?ow into the bypass
catalyst and merging to the exhaust pipe downstream of the
9. Japanese Laid-Open Patent Applications Hei 5 (1993)
branching point, an adsorber installed in the bypass, a valve
171,929 and Hei 6 (1994)-101,461 disclose similar systems. In the prior art system (described in 4-17,710), if the bypass valve 14 sticks in the closed position when the exhaust pipe valve 13 closes the exhaust pipe 5, the exhaust system becomes clogged thus rendering the engine to stall. Moreover, since the bypass 9 is connected with the EGR conduit 15 downstream of the adsorber 10, the bypass valve
40
recirculating the exhaust gas to the air intake system, valve control means which opens the valve means for a period
since starting of the engine to introduce the exhaust gas to the bypass such that the adsorber installed in the bypass 45
in the bypass to be recirculated to the air intake system through the conduit. In the system it is con?gured such that 50
bypass at the one end in the chamber.
the atmosphere.
BRIEF EXPLANATION OF THE DRAWINGS 55
FIG. 1 is an overall schematic view showing an exhaust 60
gas puri?cation system of an internal combustion engine according to the present invention having catalysts and an adsorber which adsorbs the unburnt HC component
exhausted by the engine;
conduit 15 downstream of the adsorber 10, the EGR conduit
the rear of the vehicle under the ?oor structure. The distance
These and other objects and advantages of the invention will be more apparent from the following description and
drawings, in which:
that the exhaust pipe becomes clogged. Furthermore, since the bypass is connected with the EGR may be long, depending on the engine layout. In an ordinary vehicle, the engine is usually mounted at its front and the engine exhaust system including a catalyst extends toward
the valve means is provided at or close to the branching point in the exhaust pipe and a chamber is provided close to the
branching point such that the conduit is connected to the
to the EGR conduit 15, but ?ow to the exhaust pipe 5 and to
The bypass valve 14 and the exhaust pipe valve 13 is subjected to the hot exhaust gas and should accordingly have the property of being heatproof. The provision of such a kind of valve is highly disadvantageous in terms not only of manufacturing cost but also of durability and reliability of the exhaust system. Furthermore, as mentioned above, the separate provision of the valves will increase the probability
adsorbs the unburnt component in the exhaust gas and an EGR control means which causes the exhaust gas introduced
14 is indispensable and can not be omitted. Therefore, the
system requires that both the exhaust pipe valve 13 and the bypass valve 14 are provided separately and independently of each other. In the prior art system, without the bypass valve 14, the unburnt HC component adsorbed will not ?ow
means which closes the bypass, a conduit connected to the bypass at one end and connected to the air intake system for
FIG. 2 is a cross-sectional view taken along the line Hill 65
in FIG. 1; FIG. 3 is a block diagram showing the details of an elec
tronic control unit (ECU) illustrated in FIG. 1;
