US 6,898,927 B2Granted

Emission control system with catalyst warm-up speeding control

AssigneeDenso Corporation

InventorsSyujiro Morinaga, Hisashi Iida, Yoshihiro Majima, Tatsuya Oka, Akira Ichikawa, Keiji Wakahara, Masayuki Tsutsumi, Hideyuki Maeji, Masakazu Yamada, Takanori Takahashi, Yukihiro Yamashita

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Abstract

An emission control system has a catalyst and a sensor responding to a component of exhaust gas. In order to speed warming up the catalyst, the emission control system increases the amount of heat dissipated by exhaust gas. A diagnosis of the emission control system is carried out by determining whether the amount of heat dissipated by exhaust gas is sufficient or insufficient. The amount of heat dissipated by exhaust gas is represented by the length of time to an activated state of the sensor. In the diagnosis, the amount of heat generated by a heater provided in the sensor is taken into consideration.

Claims17

Dependent claims

An emission control system, comprising:

a catalyst provided on an exhaust passage of an internal combustion engine to be used as a means for purifying exhaust gas discharged by the internal combustion engine;
a catalyst warming up speeding control means for speeding an operation to warm up the catalyst;
a diagnosis means for making a diagnosis of the catalyst warming up speeding control means in order to determine whether the catalyst warming up speeding control means is functioning normally or abnormally;
and
an exhaust gas component detection means for detecting a component contained in exhaust gas on the downstream side of the catalyst,
wherein the diagnosis means comprises:
a first diagnosis means for preliminarily detecting an abnormality of the catalyst warming up speeding control means or an abnormality caused by a deteriorating state of the catalyst on the basis of an exhaust gas component detected by the exhaust gas component detection means in the course of control executed by the catalyst warming up speeding control means to speed an operation to warm up the catalyst;
and
a second diagnosis means for confirming the deteriorating state of the catalyst on the basis of an exhaust gas component detected by the exhaust gas component detection means after completion of the control to speed an operation to warm up the catalyst, and
wherein the diagnosis means makes a diagnosis of the catalyst warming up speeding control means in order to determine whether or not an abnormality exists in the catalyst warming up speeding control means on the basis of a preliminary detection result output by the first control means and the second control means confirmation result indicating whether or not the deteriorating state of the catalyst is confirmed.

7 more elements

An emission control system comprising:

a catalyst warming up speeding means for speeding an operation to warm up a catalyst for purifying exhaust gas discharged by an internal combustion engine;
an exhaust gas sensor for detecting a concentration of a gas component such as oxygen contained in the exhaust gas and an air-fuel ratio of the exhaust gas as well as determining whether a detected air-fuel ratio is on a rich or lean side;
a heater provided in the exhaust gas sensor to be used as a means for heating a sensor element of the exhaust gas sensor;
a sensor activation determination means for determining whether or not a state of progress of an activation of the exhaust gas sensor is normal in a condition of no heat generation by the heater or in a condition of a reduced amount of heat generated by the heater in a diagnosis made during control to speed an operation to warm up the catalyst;
and
a diagnosis means for making a diagnosis of the catalyst warming up speeding means in order to determine whether or not an abnormality exists in the catalyst warming up speeding means by determining whether or not the activation of the exhaust gas sensor is abnormally late on the basis of a determination result produced by the sensor activation determination means;
the emission control system having a plurality of the exhaust gas sensors provided on the upstream side of the catalyst and an air-fuel ratio control means, wherein:
the sensor activation determination means determines whether or not a state of progress of activating any specific one of the exhaust gas sensors is normal in a condition of no heat generation by the heater employed in the specific exhaust gas sensor or in a condition of a reduced amount of heat generated by the heater employed in the specific exhaust gas sensor;
and
while the sensor activation determination means is determining whether or not a state of progress of activation of the specific exhaust gas sensor is normal, the air-fuel ratio control means controls an air-fuel ratio on the basis of signals output by the exhaust gas sensors other than the specific exhaust gas sensor in a condition of generation of heat by the heaters employed in the other exhaust gas sensors.

7 more elements

An emission control system comprising:

a catalyst warming up speeding means for speeding an operation to warm up a catalyst for purifying exhaust gas discharged by an internal combustion engine;
an exhaust gas sensor for detecting a concentration of a gas component such as oxygen contained in the exhaust gas and an air-fuel ratio of the exhaust gas as well as determining whether a detected air-fuel ratio is on a rich or lean side;
a heater provided in the exhaust gas sensor to be used as a means for heating a sensor element of the exhaust gas sensor;
a first sensor activation determination means for determining whether or not a state of progress of an activation of the exhaust gas sensor is normal during control to speed an operation to warm up the catalyst;
a first diagnosis means for making a diagnosis of the emission control system in order to determine whether or not an abnormality exists in the emission control system by determining whether the activation of the exhaust gas sensor is normal or late on the basis of a determination result produced by the first sensor activation determination means;
a second sensor activation determination means, which is used for determining whether or not a state of progress of an activation of the exhaust gas sensor is normal in a condition of no heat generation by the heater or a condition of a reduced amount of heat generated by the heater after a next start of the internal combustion engine in case a result of a diagnosis made by the first diagnosis means indicates that it is quite within the bounds of possibility that an abnormality exists;
and
a second diagnosis means for making a confirmatory diagnosis of the emission control system in order to determine whether or not an abnormality exists in the emission control system by determining whether the activation of the exhaust gas sensor is normal or late on the basis of a determination result produced by the second sensor activation determination means.

5 more elements

The emission control system comprising:

a first control means for speeding an operation to warm up a catalyst for purifying exhaust gas discharged by an internal combustion engine at a start of the internal combustion engine;
a detection means for detecting a warmed-up state of the catalyst;
and
a second control means, which is used for controlling at least one of parameters relevant to the operation to warm up the catalyst in a direction to speed the operation to warm up the catalyst in case the catalyst actual warmed-up state detected by the detection means at a predetermined point of time in the course of a process carried out by the first control means to speed the operation to warm up the catalyst has not reached a predetermined target warmed-up state of the catalyst;
wherein the second control means controls valve timings of an intake valve and/or an exhaust valve in a direction to increase a temperature of the exhaust gas for the purpose of speeding the operation to warm up the catalyst.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/270,270Filed 15 Oct 2002
Priority: JP 2001-31758816 Oct 2001
Published: US 2003/0070423 A117 Apr 2003
Granted: 31 May 2005
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

F02D 41/1496
Details: measurement of the conductivity of a sensor
F01N 3/2006
Specially adapted for catalytic conversion: periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
F01N 3/22
Characterised by methods of operation; Control: control of additional air supply only, e.g. using by-passes or variable air pump drives
F01N 11/00
Monitoring or diagnostic devices for exhaust-gas treatment apparatus