USO0RE43588E
(19) United States (12) Reissued Patent
(10) Patent Number: US (45) Date of Reissued Patent:
Akazaki et al. (54)
EXHAUST GAS PURIFICATION SYSTEM OF INTERNAL COMBUSTION ENGINE
(75) Inventors: Shusuke Akazaki, Wako (JP); Kohei
Hanada, Wako (JP); Yuji Yasui, Wako (JP); Tadashi Satoh, Wako (JP); Takashi Haga, Wako (JP) (73) Assignee: Honda Giken Kogyo Kabushiki
Kaisha, Tokyo (JP) (21) App1.N0.: 10/800,651 (22) Filed:
Related US. Patent Documents
Reissue of:
5,946,906 Sep. 7, 1999
App1.N0.:
08/975,101
Filed:
Nov. 20, 1997
US. Applications: (63)
Continuation of application No. 09/945,835, ?led on Sep. 5, 2001, noW Pat. No. Re. 42,056.
(30)
Foreign Application Priority Data
Nov. 20, 1996 (JP) (51) Int. C]. F02M 25/06
Primary Examiner * Binh Q Tran (74) Attorney, Agent, or Firm * Arent Fox LLP
(57) ABSTRACT [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 valve member Which closes the bypass, and an EGR conduit connected to the bypass at one end and connected to the air
Mar. 16, 2004
(64) Patent No.: Issued:
RE43,588 E Aug. 21, 2012
..................................... .. 8-324809
(2006.01)
intake system for recirculating the exhaust gas to the air 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. In 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 such that the conduit is connected to the bypass at the one end in the chamber. The bypass valve member is combined 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 arrange ment, the system can effectively prevent the exhaust pipe from being clogged even When a valve for closing a bypass is
(52)
US. Cl. .............. .. 60/278; 60/284; 60/288; 60/297;
(58)
Field of Classi?cation Search .................. .. 60/276,
provide a relatively short EGR conduit for recirculating
60/278, 285, 287, 284, 288, 297, 311; 123/568.11 See application ?le for complete search history.
unburnt HC component adsorbed from the adsorber and the
123/568.11
(56)
References Cited U.S. PATENT DOCUMENTS 3,699,683 A
DE
stuck in the closed position. At the same time, the system can
adsorption and desorption are conducted optimally] A system for puri?1ing exhaust gas generated by an internal combus tion 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 valve member which closes the bypass, and an E GR conduit
10/1972 Tourtellotte et a1.
(Continued)
connected to the bypass at one end and connected to the air
FOREIGN PATENT DOCUMENTS
intake system for recirculating the exhaust gas to the air intake system. The adsorber adsorbs the HC component in the exhaust gas when the exhaust gas temperature rises and the adsorbed component is recirculated to the air intake system through the E GR conduit. The bypass valve member is com
43 28 125
2/1994
(Continued) OTHER PUBLICATIONS
bined with an exhaust pipe vale member as a combination
Patent Abstract ofJapan, vol. 018, N0. 607 (M-1707), Nov. 18, 1994 & JP 06-229324 (Nissan Motor Co., Ltd.) Aug. 16, 1994.
valve such that when the bypass valve member closes the bypass, the exhaust pipe valve member opens the exhaust
MP6.
(Continued) 112 —
V/T
26
9 Claims, 17 Drawing Sheets
US RE43,588 E Page 2 US. PATENT DOCUMENTS 4,553,518 A *
5,125,231 A * 5,201,173 A * 5,207,734 A * 5,261,370 A *
11/1985
DE
4328125
4/1994
60/274 60/277 60/278
EP EP JP
0616115 0719 926 4-17710
9/1994 7/1996 1/1992
Ogawaet a1. ............... .. 123/480
11/1992
6/1992 Patiletal. 4/1993 Fujimoto et a1. 5/1993 Day et a1.
JP
4611618
5,315,824 A
5/1994 Takeshima
JP
5471929
7/1993
5,343,846 A *
9/1994 Ogawa et a1. ............... .. 123/520
5;
661-3321
3x33:
JP
8'71427
5,375,414 A *
11/1993
FOREIGN PATENT DOCUMENTS
Takao etal. ................. .. 123/478
12/1994
Adamczyket a1. ........... .. 60/274
5,388,405 A *
2/1995 Fujishita et a1. .............. .. 60/297
5,497,619 A
3/1996 Yamada et a1.
5,517,820 A *
5,524,433 A 5,544,482 A 5,589,143 A
5/1996
'
“996
OTHER PUBLICATIONS
Kuroda et a1. ................ .. 60/274
6/1996 Adamczyk, Jr, et a1, 8/1996 Matsumoto et al. 12/1996 Mori et 31.
Patent Abstract of Japan, vol. 095, N0. 005, Jun. 30, 1995 & JP 07-042538 (Fuji Heavy Ind. Ltd.) Feb. 10, 1995. Patent Abstract ofJapan, vol. 016, N0. 173 (M-1240), Apr. 24, 1992
5,606,855 A *
3/1997 Tomisawa ..................... .. 60/274
&JP 04017710 (Mazda Motor Corp), Jan. 22, 1992.
5,613,359 A *
3/1997 Zahn et a1. .................... .. 60/274
PatentAbstractsofJapan,v01.018,N0.607(M-l707),NOV.l8,1994
5,634,332 A 5,655,362 A
6/1997 Tanaka er a1 8/1997 JaWajiri eta1~
& JP 06229324 (Nissan Motor C0. Ltd), Aug. 16, 1994. Patent Abstracts of Japan, V01. 095, N0. 005, Jun. 30, 1995 & JP
5657736 A *
8/1997 Maki er a1- ~~~~~~~~~~~~~~~~~~ ~~ 123/673
07-042538 (Fuji Heavy Ind. Ltd.), Feb. 10, 1995.
5,729,971 A
3/1998 Matsuno eta1~
PatentAbstractsofJapan,v01.016,N0.173(M-1240),Apr.24, 1992
5,758,490 A 5,761,902 A
6/1998 Makl 8t a1~ 6/1998 Usam1etal.
& JP 04017710 (Mazda Motor Corp), Jan. 22, 1992.
5,956,947 A *
9/1999 Tanaka et al. ................. .. 60/297
* cited by examiner
US. Patent
N6:
Aug. 21, 2012
Sheet 1 0f 17
US RE43,588 E
US. Patent
Aug. 21, 2012
US RE43,588 E
Sheet 4 0f 17
FIG.4
<
TTRS‘ = 0
518
High S12 / TTRS 6-- TTRSLMT
N
/-/
S22
TTRS <“ O
// TRPV-ON
TRPV-OFF
kS24
US. Patent
Aug. 21, 2012
Sheet 5 0f 17
US RE43,588 E
Fl6.5
3523 E
2 m
_
_ _ w _ _
_ m
80
100
Tw (‘0)
US. Patent
Aug. 21, 2012
Sheet 6 0f 17
US RE43,588 E
FIG.6 FROM ENGINE STARTING AND LOW TEMPERATURE (HC ADSORBTXON MODE) m:
I";
52
69 I
@IQ 6] G)
HC ABSORBER
NORMAL TEMPERATURE AND WITHOUT EGR (HC TRAPPING MODE) :2:
52
r/ LL. J
V
38
r’
J
i
_ _ K‘
\ 76 ~74
FIG.8 NORMAL TEMPERATURE AND WITH EGR (HC PURGING MODE)
HC
US. Patent
Aug. 21, 2012
US RE43,588 E
Sheet70f17
F/6..9
Y
S118
Niii i < TW2
TWr
Y A.C.Swit'ch ON
5120
N Pliswiieh ON N
8122
ii S124 ii i z
TCAT : TCATRTDH
S102
"
< r, 5126
/
Control ignitionttiming Controi ignition timing under starting in retard direction
TRTD =1
(/5114 TRTDLMT
Start TRTD
[/5108 Contrni ignition timing in ordincr y manner
(
EXIT
J
US. Patent
Aug. 21, 2012
US RE43,588 E
Sheet 10 0f 17
FIG. 12
@3 Read Ne. Pb. P0. LACT
w 5200
Retrieve LCMD by Ne and Pb
M 5202
I Retrieve KEGRMAP by Ne and Pb
“W 5204
S208 5220
LCMD==LCMDk "I
1i
\s222
QACT QCMD=O
N
/
KEGRMAP=KEGRMAPk ~1 M5224
{
1
5210
.
REUHEVE QCMD by LCMD and Pb/Pq Retrieve QACT by LACT and Pb/Po
J
S272 //
Steudrstute EGR rate = 1 — KEGRMAP #5214
1 Net EGR rate = Steady-state EGR rate X (QACT/QCMD) \S
%
5216
Calculate KEGRN
(
RETURN
)
US. Patent
Aug. 21, 2012
US RE43,588 E
Sheet 11 0f 17
[-76.73
@EGRN CALCULATION) Calculate coefficient KEGRN
W 5300
KEGRN = i - net EGR rate
Store coefficient KEGRN
in ring buffer (buffer N0. = O, 1. 2, w n)
Retrieve delay time t
by Ne and Pb
\M 5304
(t = buffer No. )
Read one from among stored coefficients KEGRN by retrieved delay time t and
correct TiM~F by coefficient KEGRN
RET
/5506
US. Patent
Aug. 21, 2012
Sheet 12 or 17
F/G.I4 KEGRN
(\XCQ/K F/G.l5 Pb
US RE43,588 E
US. Patent
Aug. 21, 2012
E250
Sheet 13 0f 17
<298
EQ 82.m 5:3 m85 5E8 2C w
33q
52:8 82w 5:3 Erna 85m
‘ohmsIi4E|lL
.2.mlk
88.m 8E m
3E3
L89 =82QSE,
$2.6m SEC
3E8 m. O
C5802 F590zmw x
US RE43,588 E
US. Patent
156.7
Aug. 21, 2012
Sheet 14 or 17
US RE43,588 E
US. Patent
Aug. 21, 2012
FI I
Sheet 15 0f 17
US RE43,588 E
US. Patent
Aug. 21, 2012
Sheet 16 0f 17
w [0
L1.
FY619
US RE43,588 E
US. Patent
Aug. 21, 2012
Sheet 17 0f 17
US RE43,588 E
F/6.20
Engine starting
Calcuwte {Tout S412
qiToutgToutLMT N
9602
Y
8414
14
< High engine 100d
Read and add Tout
FTRPV = 1
/
N
5416
91504 <5 >2 Y N
5406 / TRPV-ON
(
EXIT
)
5420 J
FTRPV =10
US RE43,588 E 1
2
EXHAUST GAS PURIFICATION SYSTEM OF INTERNAL COMBUSTION ENGINE
rate provision of the valves will increase the probability that
the exhaust pipe becomes clogged. Furthermore, since the bypass is connected with the EGR conduit 15 downstream of the adsorber 10, the EGR conduit
Matter enclosed in heavy brackets [ ] appears in the original patent but forms no part of this reissue speci?ca
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
tion; matter printed in italics indicates the additions made by reissue.
rear of the vehicle under the ?oor structure. The distance
between the connection point of the bypass with the EGR conduit and the engine increases as the connection point is More than one Reissue Application ofU.S. Pat. No. 5,946, 906 has been?led. This ReissueApplication is a continuation
situated closer to the rear of the vehicle.
ofU.S. application Ser. No. 09/945, 835?led on Sep. 5, 200],
tems (disclosed in 5-171,929 and 6-101,461).
Similar disadvantages are found in the other prior art sys
which issued on Jan. 25, 20]] as US. Pat. No. RE42,056,
SUMMARY OF THE INVENTION
which is a Reissue Application of US. Pat. No. 5,946,906 issued on Sep. 7, 1999.
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 system of an internal combustion engine for removing an unburnt HC component from the exhaust gas. 2. Description of the Related Art Internal combustion engines are ordinarily provided with a
20
can effectively prevent the exhaust pipe from becoming clogged even if a valve for closing a bypass is stuck in the
closed position. 25
catalyst (a three-way catalytic converter) in the exhaust sys tem 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 activated, an unburnt HC component is immediately exhausted to the atmosphere. For that reason, there is proposed an exhaust gas puri?ca
30
an adsorber for adsorbing the unburnt HC component in the 35
again merged to the exhaust pipe 5 downstream of the 40
located such that an unburnt HC component, when adsorbed,
Laid-Open Patent Applications Hei 5 (1993)-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. More over, since the bypass 9 is connected with the EGR conduit 15 downstream of the adsorber 10, the bypass valve 14 is indis pensable and can not be omitted. Therefore, the system
from the exhaust pipe at a location downstream of the catalyst 45
point, an adsorber installed in the bypass, a valve means which closes the bypass, a conduit connected to the bypass at one end and connected to the air intake system for recirculat
ing the exhaust gas to the air intake system, valve control means which opens the valve means for a period since starting 50
55
of the engine to introduce the exhaust gas to the bypass such that the adsorber installed in the bypass adsorbs the unburnt component in the exhaust gas and an EGR control means which causes the exhaust gas introduced in the bypass to be recirculated to the air intake system through the conduit. In the system it is con?gured such that the valve means is pro vided 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 bypass at the one end in the chamber. 60
sphere. 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 manu facturing cost but also of durability and reliability of the exhaust system. Furthermore, as mentioned above, the sepa
which includes an exhaust pipe extending from an exhaust manifold of the engine and a catalyst installed in the exhaust
and merging to the exhaust pipe downstream of the branching
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 to the EGR conduit 15, but ?ow to the exhaust pipe 5 and to the atmo
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 combustion engine having an air intake system and an exhaust system
pipe, the exhaust system exhausting gas generated by the engine to the atmosphere, including a bypass branching out
is recirculated to the engine intake system through 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 the same so as to lead the exhaust gas to ?ow into the bypass 9. Japanese
can provide a relatively short EGR conduit for recirculating an unburnt HC component adsorbed from the adsorber. A third object of the invention is to provide an exhaust gas
puri?cation system of an internal combustion engine having
adsorber. An Exhaust Gas Recirculation (EGR) conduit 15 is
connected before the merging point where the bypass 9 is
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
component in the exhaust gas generated by the engine, which
tion system in Japanese Laid-Open Patent Application Hei 4(1992)-17,710. In the system, the exhaust pipe 5 is branched out at a location downstream of the catalysts 6, 7. The bypass 9 is provided with an adsorber 10 made of active carbon or activated charcoal and carried on two beds. The bypass is
component in the exhaust gas generated by the engine, which can solve the drawbacks in the prior art systems, and which
BRIEF EXPLANATION OF THE DRAWINGS
These and other objects and advantages of the invention will be more apparent from the following description and 65
drawings, in which: FIG. 1 is an overall schematic view showing an exhaust gas
puri?cation system of an internal combustion engine accord
