US2003159431A1PendingUtilityA1
Method for controlling an electrically heatable catalytic converter and exhaust-gas after-treatment system
Priority: Jan 21, 2002Filed: Jan 21, 2003Published: Aug 28, 2003
Est. expiryJan 21, 2022(expired)· nominal 20-yr term from priority
Y02T10/40F01N 3/2013Y02T10/12F01N 9/005F02D 2200/0804F01N 9/00
30
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Claims
Abstract
The invention relates to a method for controlling an electrically heatable catalytic converter for after-treating exhaust gases of an internal combustion engine. The catalytic converter is deactivated or not activated during the start of the engine if the temperature (T KAT (t abst )) of the catalytic converter exceeds a critical temperature T KRIT when starting the engine. The temperature (T KAT (t abst )) of the catalytic converter is estimated via a temperature model. The invention also relates to an exhaust-gas after-treatment system of an internal combustion engine for carrying out the method of the invention.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A method for controlling an electrically heatable catalytic converter for after treating exhaust gases of an internal combustion engine, the method comprising the steps of:
deactivating or nonactivating said catalytic converter during the start of said engine when the temperature (T KAT (t abst )) of said catalytic converter exceeds a critical temperature T KRIT ; and, utilizing a temperature model to estimate said temperature (T KAT (t abst )) of said catalytic converter.
2 . The method claim 1 , wherein said temperature model determines said temperature (T KAT (t abst )) in dependence upon the duration of switchoff when starting said engine.
3 . The method of claim 2 , wherein said temperature model determines said temperature (T KAT (t abst )) when starting said engine in accordance with the following relationship:
T KAT ( t abst )=[ T KAT ( o )− T U ]·exp(− r·c·t abst )+ T U
wherein:
T KAT (t abst ) is the temperature of said catalytic converter after a switchoff duration (t abst ) computed from a switchoff time point of said engine (t=0);
T KAT (0) is the temperature of the catalytic converter at the time point of the switchoff of said engine;
T U is the ambient temperature;
r is a thermal transition resistance; and,
c is a thermal proportionality constant.
4 . The method of claim 3 , wherein said switchoff duration (t abst ) is read in via a combination instrument and/or is determined from a model of the cool-down characteristic of said engine.
5 . The method of claim 4 , wherein said ambient temperature (T U ) is determined from the intake air temperature of said engine.
6 . The method of claim 4 , wherein a constant substitute value is used for said ambient temperature (T U ).
7 . The method of claim 3 , wherein said temperature of said catalytic converter is derived from an exhaust-gas temperature model at the time point of switching off said engine.
8 . The method of claim 3 , wherein a constant substitute value is used for said temperature of said catalytic converter at the time point of switching off said engine.
9 . A method for controlling an electrically heatable catalytic converter for after treating exhaust gases of an internal combustion engine, the method comprising the steps of:
deactivating said catalytic converter after a required heating duration (T ekat ); utilizing a temperature model to estimate said temperature (T KAT (t abst )) of said catalytic converter; and, determining a required heating characteristic and/or said required heating duration (T ekat ) from said temperature (T KAT (t abst )) during start of the engine and from the ambient temperature (T U ).
10 . The method of claim 9 , wherein said heating characteristic and/or said heating duration (t ekat ) is derived from the following relationship:
T
KAT
(
t
)
=
[
T
KAT
(
0
)
-
(
q
zu
r
+
T
U
)
]
·
exp
(
-
rct
)
+
(
q
zu
r
+
T
U
)
wherein:
T KATAB (t ekat ) is the switchoff temperature of said catalytic converter after the required heating duration (t ekat );
T KAT (0) is the temperature of the catalytic converter at the time point of the switchoff of said engine;
q zu is the entered heat in the catalytic converter because of the electric heating power thereof;
T U is the ambient temperature;
r is a thermal transition resistance; and,
c is a thermal proportionality constant.
12 . The method of claim 11 , wherein the entered heat (q zu ) is determined by measuring the heating voltage and/or the heating current of the catalytic converter.
13 . The method of claim 12 , wherein a constant substitute value is used for said entered heat (q zu ).
14 . The method of claim 10 , wherein said required heating duration (t ekat ) up to reaching said required switchoff temperature (T KATAB ) is determined by the following relationship:
t
ekat
=
1
r
·
c
·
ln
(
T
KAT
(
0
)
-
q
zu
r
-
T
U
T
KATAB
-
q
zu
r
-
T
U
)
.
15 . The method of claim 10 , wherein the required heating duration (t EKAT ) up to reaching the needed switchoff temperature (T KATAB ) is determined from continued computation of the catalytic converter temperature (T KAT ) with the currently elapsed heating duration (t) and the subsequent comparison of the result to the switchoff temperature (T KATAB ).
16 . The method of claim 15 , wherein the catalytic converter is deactivated or not activated when a diagnostic method diagnoses a fault.
17 . The method of claim 16 , wherein said fault is in the feed lines to said catalytic converter.
18 . The method of claim 16 , wherein said catalytic converter is deactivated or not activated when there is a danger that the catalytic converter can freeze up at low ambient temperature.
19 . The method of claim 16 , wherein said catalytic converter is deactivated or not activated when said engine stalls during the heating phase of said catalytic converter.
20 . An exhaust-gas after treatment arrangement of an internal combustion engine having an exhaust-gas system, the arrangement comprising:
an E-catalytic converter mounted in said exhaust-gas system; and, a control apparatus for carrying out the method including the steps of:
deactivating or nonactivating said catalytic converter when starting said engine when the temperature (T KAT (t abst )) of said catalytic converter exceeds a critical temperature T KRIT ; and,
utilizing a temperature model to estimate said temperature (T KAT (t abst )) of said catalytic converter.Join the waitlist — get patent alerts
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