GB2277463A - Estimating the temperature of a catalytic converter - Google Patents
Estimating the temperature of a catalytic converter Download PDFInfo
- Publication number
- GB2277463A GB2277463A GB9309075A GB9309075A GB2277463A GB 2277463 A GB2277463 A GB 2277463A GB 9309075 A GB9309075 A GB 9309075A GB 9309075 A GB9309075 A GB 9309075A GB 2277463 A GB2277463 A GB 2277463A
- Authority
- GB
- United Kingdom
- Prior art keywords
- catalytic converter
- matrices
- temperature
- flow
- internal combustion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N9/00—Electrical control of exhaust gas treating apparatus
- F01N9/005—Electrical control of exhaust gas treating apparatus using models instead of sensors to determine operating characteristics of exhaust systems, e.g. calculating catalyst temperature instead of measuring it directly
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
- F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
- F01N13/0097—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
- F01N3/204—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using an exhaust gas igniter, e.g. a spark or glow plug, without introducing fuel into exhaust duct
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/30—Arrangements for supply of additional air
- F01N3/32—Arrangements for supply of additional air using air pump
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
An internal combustion engine 12 has an exhaust system 14 fitted with a catalytic converter 10, 11 in which pressure sensing means 56, 58 are provided for monitoring the flow resistance across one or matrices of the catalytic converter to provide an indication of the temperature of the catalytic converter. This allows heating regimes to be switched off and so avoid overheating. <IMAGE>
Description
ESTIMATING THE TEMPERATURE OF A CATALYTIC CONVERTER
Field of the invention
The invention is concerned with estimating the temperature of a catalytic converter in the exhaust system of an internal combustion engine.
Background of the invention
The efficiency of a catalytic converter drops dramatically when it is operating below its so-called light off temperature. For this reason, various systems have been devised for heating the catalyst of a catalytic converter during cold starts but as it is also important to avoid overheating a reliable method is required to assess the operating temperature of the catalyst.
One can use elements like thermistors and thermocouples to measure catalyst temperature directly, but the reliability of such devices cannot be guaranteed over 100,000 miles of vehicle operation, as currently proposed legislation would require.
One has therefore to resort to indirect but more reliable methods of estimating the temperature of the catalytic converter and this invention aims to do so without adding significantly to the complexity and cost of the engine.
Summary of the invention
According to a first aspect of the present invention, there is provided an internal combustion engine having an exhaust system fitted with a catalytic converter, wherein means are provided for monitoring the resistance to fluid flow through at least part of the catalytic converter to provide an indication of the temperature of the catalytic converter.
The means for monitoring the resistance to fluid flow may suitably comprise means for measuring the pressure drop across the catalytic converter and means for assessing the mass gas flow through the catalytic converter. From these two measurements, one may determine the resistance to gas flow presented by the catalytic converter, which will vary as a function of the gas viscosity that itself depends upon the gas temperature. Because of the large area of contact between the gases and the catalytic converter, these two will be at substantially the same temperature and the flow resistance measurement is therefore related to the catalyst temperature.
Conveniently, the means for assessing the mass of the exhaust gases comprise means for measuring the intake air flow and the flow of any air introduced directly into the exhaust system without passing through the combustion chambers of the engine.
In an alternative embodiment of the invention, there is provided an internal combustion engine having an exhaust system fitted with a catalytic converter that comprises two catalytic matrices arranged in series with one another in the direction of flow of the engine exhaust gases and heating means between the two matrices for heating the second of the matrices, wherein pressure sensing means are provided for sensing the flow resistance through the two matrices of the catalytic converter, and means are provided for comparing the pressure drops across the matrices to provide an indication of the relative temperature of the matrices.
In the latter aspect of the invention, use is made of the presence of two catalytic converter matrices to eliminate the dependence upon the mass flow. Because the same gases are flowing through both matrices, the pressure difference is attributable to the difference in temperature alone.
This invention therefore solves the problem of estimating catalyst temperature by using a reliable pressure difference sensor that is commonly used in feedback systems for controlling the flow of exhaust gas recirculation in automobile engines.
Brief description of the drawings
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which the single figure shows diagrammatically an engine having an exhaust gas ignition system for heating the second of two matrices in its catalytic converter and a pressure difference sensing arrangement for providing an indication of the temperature of the second matrix.
Description of the Preferred embodiment
An engine 12 having an exhaust gas ignition (EGI) system comprises an intake system having an air mass meter 22, a butterfly throttle 24 and fuel injectors 20. The exhaust system includes a down pipe 14 leading to a catalytic converter that comprises two matrices 10, 11 disposed within a common housing and separated from one another by an afterburner chamber 16 containing an igniter 18. An air pump 30 serves to introduce additional air into the exhaust system through a flow control valve 32. The engine also includes a heated exhaust oxygen (HEGO) sensors 38 positioned near the exhaust ports.
As so far described, the engine is known. In the present invention, pressure sensing means are associated with the catalytic converter to provide an estimate of its temperature. The pressure sensing means comprise a first sensor 56 connected by pipes 50, 52 across the first catalytic matrix 10 and a second sensor 58 connected by pipes 52, 54 across the second catalytic matrix 11.
When the engine is warm, the pump 30 does not introduce additional air into the exhaust system and the HEGO sensor 38 is used to set the air to fuel ratio supplied to the engine at stoichiometry. The catalytic converter, which acts as a three-way catalyst, operates most efficiently under these conditions to reduce hydrocarbons, carbon monoxide and nitrogen oxides in the exhaust gases.
During cold starts, the catalytic converter does not operate until it reaches its light-off temperature and the EGI system is intended to minimise the light-off time of the catalytic converter. During cold start, the mixture supplied to the engine is enriched to the point where a significant concentration of hydrogen is present in the exhaust gases. Air is added into the exhaust system by means of the pump 30 and the control valve 32 to restore the stoichiometry of the gases reaching the catalytic converter.
Within the afterburner chamber 16, this mixture is burnt using the igniter 18 and the heat generated rapidly heats the front face of the second matrix 11 to its light off temperature. The EGI system is then switched off to extinguish the afterburner flame.
At this point, there is a risk that the second matrix 11 could be cooled down again by the cold exhaust gases and this is prevented by switching to a catalyst temperature management (CTM) regime. In this regime, a mixture is supplied to the engine that it not rich enough to allow ignition of the cold exhaust gases but nevertheless contains carbon monoxide and hydrocarbons that can react exothermically with additional air supplied by the pump 30 in the presence of the partly operational catalytic converter to continue heating the remainder of the catalyst.
During the time that the engine intake charge is controlled to allow exhaust gas ignition or catalyst temperature control, it is advantageous to be able to determine the temperature of the catalyst so that control can be carried out by closed loop rather than open loop. Previously, temperature sensors based on thermistors have been proposed for this purpose but they have not been used commercially because their long term reliability has not been proven.
To overcome this problem, the present invention measures the resistance to flow of a catalytic matrix by measuring the pressure difference across it. The viscosity of the exhaust gases increases with increasing temperature and at any given mass flow rate the pressure difference across the catalytic matrix will be temperature dependent. It would be possible to take a pressure reading from across the second matrix only and to determine the temperature after allowing for the computed mass flow. This could be determined from the signal of the meter 22 in the intake system and the signal applied to the flow control valve 32.
The illustrated preferred embodiment of the invention, however, provides an easier and more elegant method by making use of the fact that the afterburner only affects the temperature of the second matrix 11 and to a major extent the same also applies to the ensuring CTM regime. As the two matrices 10 and 11 are connected in series with one another, the mass flow through them is the same.
Furthermore, as they substantially identical in construction, the only difference between affecting their resistance to gas flow is their temperature. A comparison of the signals from the pressure difference sensors 56 and 58 can therefore produce a signal indicative of the extent to which the second catalytic converter has been heated by the
EGI and CTM regimes. This signal can be used in closed loop control to ensure as rapid a light-off as possible without causing damage to the catalyst by overheating.
The output signals from the two sensors can be compared in different ways, for example they may be subtracted one from the other or divided one by the other. Ideally, the processing should yield a parameter that is strongly dependent on temperature and independent of other factors.
However, with the amount of signal processing that can readily be carried out using on board computers, it may be more convenient in some cases to employ a parameter, such as the pressure across a single matrix, that varies with other operating parameters and to correct for these other parameters by a means of look up tables in the computer or other suitable control algorithms.
Claims (3)
1. An internal combustion engine having an exhaust system fitted with a catalytic converter, wherein means are provided for monitoring the resistance to fluid flow through at least part of the catalytic converter to provide an indication of the temperature of the catalytic converter.
2. An internal combustion engine as claimed in claim 1, wherein the means for monitoring the resistance to fluid flow comprise means for measuring the pressure drop across the catalytic converter and means for assessing the mass gas flow through the catalytic converter.
3. An internal combustion engine constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawing.
3. An internal combustion engine as claimed in claim 2, wherein the means for assessing the mass of the exhaust gases comprise means for measuring the intake air flow and the flow of any air introduced directly into the exhaust system without passing through the combustion chambers of the engine.
4. An internal combustion engine having an exhaust system fitted with a catalytic converter that comprises two catalytic matrices arranged in series with one another in the direction of flow of the engine exhaust gases and heating means between the two matrices for heating the second of the matrices, wherein pressure sensing means are provided for sensing the flow resistance through the two matrices of the catalytic converter, and means are provided for comparing the pressure drops across the matrices to provide an indication of the relative temperature of the matrices.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9309075A GB2277463A (en) | 1993-05-01 | 1993-05-01 | Estimating the temperature of a catalytic converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9309075A GB2277463A (en) | 1993-05-01 | 1993-05-01 | Estimating the temperature of a catalytic converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9309075D0 GB9309075D0 (en) | 1993-06-16 |
| GB2277463A true GB2277463A (en) | 1994-11-02 |
Family
ID=10734832
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9309075A Withdrawn GB2277463A (en) | 1993-05-01 | 1993-05-01 | Estimating the temperature of a catalytic converter |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2277463A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108223078A (en) * | 2017-12-31 | 2018-06-29 | 无锡威孚力达催化净化器有限责任公司 | A kind of method using catalytic cleaner pressure drop assay optimization CFD calculation of backpressure |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1461804A (en) * | 1973-02-28 | 1977-01-19 | Alfa Romeo Spa | Device for detecting the overheating of a catalyst traversed by the exhaust gas of an internal combustion engine |
| GB2131321A (en) * | 1982-12-01 | 1984-06-20 | Lucas Ind Plc | Engine system |
| EP0115722B1 (en) * | 1982-12-28 | 1986-09-10 | Automobiles Peugeot | Control device for a regeneration procedure of a particle filter for the exhaust pipe of a diesel engine |
-
1993
- 1993-05-01 GB GB9309075A patent/GB2277463A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1461804A (en) * | 1973-02-28 | 1977-01-19 | Alfa Romeo Spa | Device for detecting the overheating of a catalyst traversed by the exhaust gas of an internal combustion engine |
| GB2131321A (en) * | 1982-12-01 | 1984-06-20 | Lucas Ind Plc | Engine system |
| EP0115722B1 (en) * | 1982-12-28 | 1986-09-10 | Automobiles Peugeot | Control device for a regeneration procedure of a particle filter for the exhaust pipe of a diesel engine |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108223078A (en) * | 2017-12-31 | 2018-06-29 | 无锡威孚力达催化净化器有限责任公司 | A kind of method using catalytic cleaner pressure drop assay optimization CFD calculation of backpressure |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9309075D0 (en) | 1993-06-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |