U.S. patent application number 15/573264 was filed with the patent office on 2018-05-17 for method for flushing an exhaust-gas cleaning system.
The applicant listed for this patent is GE Jenbacher GmbH & Co. OG. Invention is credited to Friedhelm HILLEN, Max MEHRING.
Application Number | 20180135484 15/573264 |
Document ID | / |
Family ID | 56403915 |
Filed Date | 2018-05-17 |
United States Patent
Application |
20180135484 |
Kind Code |
A1 |
HILLEN; Friedhelm ; et
al. |
May 17, 2018 |
METHOD FOR FLUSHING AN EXHAUST-GAS CLEANING SYSTEM
Abstract
A method for flushing an exhaust-gas cleaning system of an
internal combustion engine having a catalytic converter with at
least one catalyst bed, whereby an exhaust gas from the internal
combustion engine is supplied to the exhaust-gas cleaning system in
an active operating phase of the exhaust-gas cleaning system, and
no exhaust gas is supplied to the exhaust-gas cleaning system in a
passive operating phase of the exhaust-gas cleaning system, whereby
a temperature of the at least one catalyst bed is determined and
the flushing is performed depending on the determined temperature,
whereby the exhaust-gas cleaning system is flushed in the passive
operating phase of the exhaust-gas cleaning system by a flushing
device, which is connected directly to an exhaust-gas line.
Inventors: |
HILLEN; Friedhelm; (Jenbach,
AT) ; MEHRING; Max; (Jenbach, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GE Jenbacher GmbH & Co. OG |
Jenbach |
|
AT |
|
|
Family ID: |
56403915 |
Appl. No.: |
15/573264 |
Filed: |
May 9, 2016 |
PCT Filed: |
May 9, 2016 |
PCT NO: |
PCT/AT2016/050135 |
371 Date: |
November 10, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02T 10/12 20130101;
F01N 11/002 20130101; Y02T 10/47 20130101; Y02T 10/26 20130101;
Y02T 10/40 20130101; F01N 3/2046 20130101; F01N 2900/1602 20130101;
F01N 2270/02 20130101; F01N 2260/022 20130101; F01N 3/20 20130101;
F01N 3/04 20130101 |
International
Class: |
F01N 3/04 20060101
F01N003/04; F01N 3/20 20060101 F01N003/20 |
Foreign Application Data
Date |
Code |
Application Number |
May 11, 2015 |
AT |
A50384/2015 |
Claims
1. A method for flushing an exhaust-gas cleaning system of an
internal combustion engine comprising a catalytic converter with at
least one catalyst bed, wherein an exhaust gas from the internal
combustion engine is supplied to the exhaust-gas cleaning system in
an active operating phase of the exhaust-gas cleaning system, and
no exhaust gas is supplied to the exhaust-gas cleaning system in a
passive operating phase of the exhaust-gas cleaning system, wherein
a temperature of the at least one catalyst bed is determined and
the flushing is performed depending on the determined temperature,
wherein the exhaust-gas cleaning system is flushed in the passive
operating phase of the exhaust-gas cleaning system by a flushing
device, which is connected directly to an exhaust-gas line.
2. The method according to claim 1, wherein the exhaust-gas
cleaning system is flushed only in the passive operating phase of
the exhaust-gas cleaning system.
3. The method according to claim 1, wherein the temperature of the
at least one catalyst bed is determined in the passive operating
phase of the exhaust-gas cleaning system.
4. The method according to claim 1, wherein the exhaust-gas
cleaning system is flushed after a shutdown of the internal
combustion engine.
5. The method according to claim 1, wherein a period of time during
which the exhaust-gas cleaning system is flushed is determined
depending on the determined temperature.
6. The method according to claim 1, wherein the exhaust-gas
cleaning system is flushed before a start-up of the internal
combustion engine.
7. The method according to claim 1, wherein the exhaust-gas
cleaning system is flushed until the temperature of the at least
one catalyst bed is lower than or equal to a predetermined setpoint
temperature.
8. The method according to claim 7, wherein the exhaust-gas
cleaning system is flushed if the temperature of the at least one
catalyst bed before flushing is higher than or equal to a
predetermined threshold value E.
9. The method according to claim 1, wherein a first exhaust-gas
temperature value is determined upstream of the catalytic converter
and a second exhaust-gas temperature value is determined downstream
of the catalytic converter, wherein the temperature of the at least
one catalyst bed is determined by taking account of the first
exhaust-gas temperature value and the second exhaust-gas
temperature value.
Description
BACKGROUND OF THE INVENTION
[0001] Embodiments of the invention relate to a method for flushing
an exhaust-gas cleaning system of an internal combustion engine
comprising a catalytic converter with at least one catalyst bed,
whereby an exhaust gas from the internal combustion engine is
supplied to the exhaust-gas cleaning system in an active operating
phase of the exhaust-gas cleaning system and no exhaust gas is
supplied to the exhaust-gas cleaning system in a passive operating
phase of the exhaust-gas cleaning system, whereby a temperature of
the at least one catalyst bed is determined and the flushing is
performed depending on the determined temperature.
[0002] Methods for flushing a catalytic converter installed in an
exhaust-gas cleaning system of an internal combustion engine with
at least one catalyst bed are already known in order to cool a
catalyst bed that is too strongly heated during the operation of
the internal combustion engine, so as to prevent overheating and
associated damage to the catalyst bed (e.g. DE 2401287, EP 1033480
A1).
[0003] Experiments by the applicant have shown that, after shutting
down an internal combustion engine, e.g. a stationary
reciprocating-piston gas engine, the exhaust-gas temperature
downstream of an exhaust-gas turbine of a turbocharger can increase
to more than 400.degree. C. This increase in the exhaust-gas
temperature leads to heating of a catalytic converter arranged in
the exhaust-gas cleaning system. If the internal combustion engine
is then to be restarted but suffers a false start, then the
exhaust-gas lines and thus also the exhaust-gas cleaning system
together with the catalytic converter are filled with a
fuel-gas/air mixture. Depending on the temperature of the catalyst
bed of the catalytic converter and the number of unsuccessful start
attempts in series, undesirable oxidation of the fuel gas can
occur, which can lead to damage to the catalytic converter and, in
the worst case, even to a deflagration.
BRIEF DESCRIPTION OF THE INVENTION
[0004] The object of embodiments of the invention is therefore to
provide an improved method, improved in comparison with the prior
art, for flushing an exhaust-gas cleaning system of an internal
combustion engine comprising a catalytic converter with at least
one catalyst bed, by means of which a safer start-up of the
internal combustion engine can be achieved.
[0005] This object is achieved according to embodiments of the
invention by a method for flushing an exhaust-gas cleaning system
of an internal combustion engine comprising a catalytic converter
with at least one catalyst bed, wherein an exhaust gas from the
internal combustion engine is supplied to the exhaust-gas cleaning
system in an active operating phase of the exhaust-gas cleaning
system, and no exhaust gas is supplied to the exhaust-gas cleaning
system in a passive operating phase of the exhaust-gas cleaning
system, wherein a temperature of the at least one catalyst bed is
determined and the flushing is performed depending on the
determined temperature, wherein the exhaust-gas cleaning system is
flushed in the passive operating phase of the exhaust-gas cleaning
system by a flushing device, which is connected directly to an
exhaust-gas line. Embodiments of the invention are defined in the
dependent claims.
[0006] According to embodiments of the invention, it is thus
provided that the exhaust-gas cleaning system is flushed in the
passive operating phase of the exhaust-gas cleaning system.
[0007] With regard to the exhaust-gas cleaning system, in principle
two types of operating phases are distinguished. An active
operating phase of the exhaust-gas cleaning system is characterized
in that an exhaust gas from the internal combustion engine is fed
into the exhaust-gas cleaning system. A passive operating phase of
the exhaust-gas cleaning system is characterized in that no exhaust
gas is fed into the exhaust-gas cleaning system. During the ongoing
operation of an internal combustion engine, during which the
exhaust-gas cleaning system is supplied with an exhaust gas from
the internal combustion engine, the exhaust-gas cleaning system is
thus in an active operating phase.
[0008] By flushing the exhaust-gas cleaning system in a passive
operating phase of the exhaust-gas cleaning system, an influence on
the exhaust-gas cleaning system can also be exerted outside of an
active operating phase of the exhaust-gas cleaning system. In
particular, the overheating of the catalytic converter or its
catalyst beds can be prevented after the shutdown of an internal
combustion engine or before the start-up of an internal combustion
engine after previous false starts.
[0009] A flushing of the exhaust-gas cleaning system can be
performed by a flushing device, which has its own drive. This has
the significant advantage that the flushing of the exhaust-gas
cleaning system can be performed independently of the operating
state of the internal combustion engine. This also makes it
possible to perform a flushing operation when the internal
combustion engine is in a passive operating state. Furthermore, the
disadvantages, such as when using an electric turbocharger as a
flushing device, which forcibly cools the internal combustion
engine, are thereby eliminated. Since only the exhaust-gas cleaning
system is flushed by a separately driven flushing device and thus
also cooled, no undesirable cooling of the internal combustion
engine occurs. Such a separate drive of the flushing device can be
designed e.g. as an electric motor.
[0010] In an embodiment, it can be provided that the exhaust-gas
cleaning system is flushed only in the passive operating phase of
the exhaust-gas cleaning system. In other words, the exhaust-gas
cleaning system is flushed exclusively in the passive operating
phases of the exhaust-gas cleaning system, in which no exhaust gas
is fed into the exhaust-gas cleaning system.
[0011] It can, in an embodiment, be provided that the temperature
of the at least one catalyst bed is determined in the passive
operating phase of the exhaust-gas cleaning system.
[0012] According to an embodiment, it can be provided that the
exhaust-gas cleaning system is flushed after a shutdown of the
internal combustion engine. As a result, a combustible fuel/air
mixture which is still present in the exhaust tract is removed from
the exhaust tract before restarting the internal combustion
engine.
[0013] A particular embodiment variant provides that a period of
time is determined depending on the determined temperature, during
which the exhaust-gas cleaning system is flushed. In determining
the period of time, it can be considered that, in the case of a hot
catalyst or catalyst bed, it must be flushed for a longer time than
in the case of a colder catalyst or catalyst bed, so as to ensure
that no combustible fuel/air mixture is still present in the
exhaust tract.
[0014] According to an embodiment, it can be provided that the
exhaust-gas cleaning system is flushed after a start-up of the
internal combustion engine. In this way, it can be ensured that,
when the internal combustion engine is started up, there is no
longer any combustible fuel/air mixture present which can damage
the catalytic converter due to undesirable oxidation in the
catalytic converter.
[0015] It has been found to be particularly advantageous that the
exhaust-gas cleaning system is flushed until the temperature of the
at least one catalyst bed is lower than or equal to a predetermined
setpoint temperature. The predetermined setpoint temperature can
thus, in an embodiment, be selected such that, below the
predetermined setpoint temperature, no significant risk arises from
the catalytic converter serving as ignition source. Depending on
the dimensioning of the catalytic converter and the fuel-gas
quality used, the predetermined setpoint temperature can be in a
range from around 200.degree. C. to around 400.degree. C., for
example around 300.degree. C.
[0016] It can thus be provided that the exhaust-gas cleaning system
is flushed if the temperature of the at least one catalyst bed
before flushing is higher than or equal to a predetermined
threshold value. The predetermined threshold value can thus, in an
embodiment, be selected such that, below the predetermined
threshold value, no significant risk arises from the catalytic
converter serving as ignition source. Depending on the dimensioning
of the catalytic converter, the predetermined threshold value can
be in a range from around 200.degree. C. to around 400.degree. C.,
for example around 300.degree. C.
[0017] In the event that the temperature of the at least one
catalyst bed is lower than the predetermined threshold value, it
can be provided that a so-called safety flush occurs for a
predetermined period of time, which may be in a range from around
30 seconds to around 225 seconds, depending on the size of the
exhaust tract.
[0018] In an embodiment, it can be provided that a first
exhaust-gas temperature value is determined upstream of the
catalytic converter and a second exhaust-gas temperature value is
determined downstream of the catalytic converter, whereby the
temperature of the at least one catalyst bed is determined by
taking account of the first exhaust-gas temperature value and the
second exhaust-gas temperature value.
[0019] In an embodiment, it can be provided that the exhaust-gas
cleaning system is flushed with air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Further details and advantages of this invention are
explained in more detail below in the description of the figures,
with reference to the exemplary embodiments shown in the drawings.
The figures show the following:
[0021] FIG. 1 shows an internal combustion engine with an
exhaust-gas cleaning system,
[0022] FIG. 2 shows a flowchart relating to the flushing of an
exhaust-gas cleaning system after the shutdown of an internal
combustion engine,
[0023] FIG. 3 shows a flowchart relating to the flushing of an
exhaust-gas cleaning system before the start-up of an internal
combustion engine.
DETAILED DESCRIPTION
[0024] FIG. 1 shows an internal combustion engine 4, in the
exhaust-gas line 5 of which an exhaust-gas cleaning system 3 is
arranged. The internal combustion engine 4 in this example is a
stationary gas engine, which is operated with a fuel-gas/air
mixture. The exhaust-gas cleaning system 3 comprises a catalytic
converter 1, which in this example is equipped with two catalyst
beds 2. Upstream of the exhaust-gas cleaning system 3, a flushing
device 6 is arranged, through which the air L can be introduced
into the exhaust-gas line 5 upstream of the exhaust-gas cleaning
system 3 in order to flush the exhaust-gas cleaning system 3.
[0025] According to the proposed method, the exhaust-gas cleaning
system 3 is flushed depending on a determined temperature T of the
catalyst beds 2 of the catalytic converter 1. To determine the
temperature T in this example, two temperature sensors 7, 8 are
arranged upstream and downstream of the exhaust-gas cleaning system
3. The temperature sensors 7, 8 determine the temperature of the
exhaust gas of the internal combustion engine 4. The temperature
sensor 7 detects a first exhaust-gas temperature value T1 upstream
of the catalytic converter 1, and the temperature sensor 8
determines a second exhaust-gas temperature value T2 downstream of
the catalytic converter 1. The determined exhaust-gas temperature
values T1, T2 are reported via signal lines 10 to a control device
9, which determines an estimated temperature T of the catalyst beds
2 from the first exhaust-gas temperature value T1 and the second
exhaust-gas temperature value T2. This determination of the
temperature T of the catalyst beds 2 can be performed e.g. by
calculating the arithmetic mean of the first exhaust-gas
temperature value T1 and the second exhaust-gas temperature value
T2, or e.g. further calculations are performed, taking into account
the caloric influencing variables, the response times of the
measurement signal chains and the operating history. Depending on
the determined temperature T, the control device 9 can activate the
flushing device 6 via a control line 11 in order to introduce air L
upstream of the exhaust-gas cleaning system 3 into the exhaust-gas
line 5, thereby flushing the exhaust-gas cleaning system 3.
[0026] FIG. 2 shows, by way of example, a flowchart relating to the
flushing of the exhaust-gas cleaning system 3 after the shutdown of
an internal combustion engine 4. Starting from step S1, in which
the internal combustion engine runs and supplies exhaust gas to the
exhaust-gas cleaning system 3, whereby the exhaust-gas cleaning
system 3 is in an active operating phase, a stop command for
stopping the internal combustion engine 4 is initiated in step S2.
Accordingly, the internal combustion engine 4 is stopped in step
S3. As a result, no further exhaust gas from the internal
combustion engine 4 is fed into the exhaust-gas cleaning system 3,
and the exhaust-gas cleaning system 3 is in a passive operating
phase in step S4. In this passive operating phase of the
exhaust-gas cleaning system 3, the temperature T of the at least
one catalyst bed 2 of the catalytic converter 1 of the exhaust-gas
cleaning system 3 is now determined in step S5. In step S6, a
period of time tp is determined depending on the determined
temperature T of the at least one catalyst bed 2, during which the
exhaust-gas cleaning system 3 is flushed in step S7.
[0027] FIG. 3 shows, by way of example, a flowchart for the
flushing of the exhaust-gas cleaning system 3 before the start-up
of an internal combustion engine 4. In step S8, a passive operating
phase of the exhaust-gas cleaning system 3 is then assumed, which
may be caused by the fact that the internal combustion engine 4 is
not running. In step S9, the start command for starting the
internal combustion engine 4 is executed. In step S10, it is
checked whether the start command was preceded by a false start of
the internal combustion engine 4, or whether the internal
combustion engine 4 was previously shut down (e.g. within a
predefined period). If a false start has not occurred and the
internal combustion engine 4 was not shut down recently, the
temperature T of the at least one catalyst bed 2 of the catalytic
converter 1 of the exhaust-gas cleaning system 3 is determined in
step S11. In step S12, it is checked whether the determined
temperature T of the at least one catalyst bed 2 is lower than or
equal to a setpoint temperature value TS. If this is not the case
and the temperature T is higher than the setpoint temperature value
TS, then the exhaust-gas cleaning system 3 is flushed in step S13,
and in step S11 the determination of the temperature T of the at
least one catalyst bed 2 is continued. If it is found in step S12
that the temperature T of the at least one catalyst bed 2 is lower
than or equal to the setpoint temperature TS, then the internal
combustion engine 4 can be started in step S14. By starting the
internal combustion engine 4, an exhaust gas from the internal
combustion engine 4 is fed into the exhaust-gas cleaning system 3,
and the exhaust-gas cleaning system 3 is in an active operating
phase in step S15.
[0028] If it is determined in step S10 that a false start of the
internal combustion engine 4 has previously occurred, or the
internal combustion engine 4 was shut down recently, the
temperature T of the at least one catalyst bed 2 is determined in
step S16, and in step 17 it is checked whether the temperature T of
the at least one catalyst bed 2 is higher than or equal to a
threshold value TT. If this is the case and thus the temperature T
is higher than or equal to the threshold value TT, then we continue
in step S12. If this is not the case and thus the temperature T is
lower than the threshold value TT, then a safety flush of the
exhaust-gas cleaning system 3 is performed in step S18. The
exhaust-gas cleaning system 3 can thus be flushed for a fixed
predetermined duration of e.g. 30 to 225 seconds, depending on the
size of the exhaust tract. After this safety flush in step S18,
step S14 (starting of the internal combustion engine 4) is
continued.
[0029] This written description uses examples to disclose the
invention, including the preferred embodiments, and also to enable
any person skilled in the art to practice the invention, including
making and using any devices or systems and performing any
incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those skilled in the art. Such other examples are intended to be
within the scope of the claims if they have structural elements
that do not differ from the literal language of the claims, or if
they include equivalent structural elements with insubstantial
differences from the literal languages of the claims.
* * * * *