WO2018024391A1 - Commande de moteur pour régénération de filtre à particules de gaz d'échappement - Google Patents

Commande de moteur pour régénération de filtre à particules de gaz d'échappement Download PDF

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Publication number
WO2018024391A1
WO2018024391A1 PCT/EP2017/064375 EP2017064375W WO2018024391A1 WO 2018024391 A1 WO2018024391 A1 WO 2018024391A1 EP 2017064375 W EP2017064375 W EP 2017064375W WO 2018024391 A1 WO2018024391 A1 WO 2018024391A1
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WO
WIPO (PCT)
Prior art keywords
particulate filter
exhaust gas
oxygen content
exhaust system
downstream
Prior art date
Application number
PCT/EP2017/064375
Other languages
English (en)
Inventor
Nick WICKS
Michael Davies
David BLAIKLEY
Ian Parsons
Original Assignee
Jaguar Land Rover Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Jaguar Land Rover Limited filed Critical Jaguar Land Rover Limited
Priority to DE112017003919.3T priority Critical patent/DE112017003919T5/de
Publication of WO2018024391A1 publication Critical patent/WO2018024391A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1439—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the position of the sensor
    • F02D41/1441—Plural sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
    • F02D41/029—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a particulate filter
    • 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
    • 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
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • 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
    • F01N3/101—Three-way catalysts
    • 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
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/1454—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an oxygen content or concentration or the air-fuel ratio
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1473—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
    • F02D41/1475—Regulating the air fuel ratio at a value other than stoichiometry
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/1454—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an oxygen content or concentration or the air-fuel ratio
    • F02D41/1456—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an oxygen content or concentration or the air-fuel ratio with sensor output signal being linear or quasi-linear with the concentration of oxygen

Definitions

  • the present disclosure relates to engine control method and apparatus. Particularly, but not exclusively, the present disclosure relates to an engine control unit; to a vehicle; and to a method of controlling an internal combustion engine.
  • the engine control unit has particular application for a gasoline engine.
  • a vehicle having an internal combustion engine typically includes aftertreatment systems for treating exhaust gas expelled during a combustion cycle of the internal combustion engine.
  • the aftertreatment systems are provided in an exhaust system for conveying exhaust gas from the internal combustion engine. It is well known to provide one or more catalytic converter, such as a three-way catalyst (TWC), for reducing carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxides (NOx).
  • the exhaust system of a gasoline engine may comprise a starter catalyst and a main catalyst, for example.
  • the aftertreatment system may also include a particulate filter.
  • the particulate filter traps carbonaceous particulate material to prevent them being released to atmosphere with the exhaust gas. The particulate filter is regenerated by oxidising the carbonaceous particulate material.
  • the oxidation is performed at high temperatures in the presence of oxygen. Oxidisation may occur at temperatures greater than 400 ⁇ but the rate increases exponentially with temperature.
  • the oxidation rate in the temperature range 400 °C to 500 'C may, for example, be relatively slow (although it may prove useful for passive regeneration of the particulate filter). At temperatures above 500 °C, the oxidation rate is higher and regeneration of the particulate filter may be performed to oxidise accumulated carbonaceous particulate material.
  • the oxidation temperature is preferably greater than 600 °C for a coated gasoline particulate filter; and preferably greater than 650 ⁇ for an uncoated gasoline particulate filter.
  • the gasoline engine operates under stoichiometric conditions and there is a small amount of oxygen available in the exhaust gas and this is used for oxidation of carbon monoxide (CO) and unburnt hydrocarbons (UHC) in the catalytic converter.
  • CO carbon monoxide
  • UHC unburnt hydrocarbons
  • the prime source of oxygen for oxidation of the carbonaceous particulate material in the GPF in normal operation will be during deceleration fuel shut-off, however this will not provide for customer duty cycles which do not experience sufficient deceleration and/or fuel cut-off events.
  • control modes such as 'coasting' and 'sailing', may be implemented and these may reduce the number of deceleration events suitable for regenerating the particulate filter.
  • the frequency with which suitable deceleration events occur in Mild Hybrid Electric Vehicles (MHEV) and Plug-in Hybrid Electric Vehicles (PHEV) may also be lower.
  • MHEV Mild Hybrid Electric Vehicles
  • PHEV Plug-in Hybrid Electric Vehicles
  • Typical gasoline systems place a Heated Exhaust Gas Oxygen (HEGO) sensor after the starter catalyst and ahead of the main catalyst.
  • the GPF will typically be placed in the main catalyst position (for example, a coated GPF to replace TWC); or further back in the exhaust system (for example, an additional uncoated GPF).
  • the engine control unit is configured to control fuelling of the gasoline engine to maintain lambda ( ⁇ ) at least substantially equal to one (1 ) based on a balance of gaseous exhaust emissions reacting in the TWC. This will limit the amount of oxygen available for oxidation of the carbonaceous particulate material in the GPF during closed loop operation.
  • the present invention seeks to provide a control apparatus and method which overcomes or ameliorates at least some of the limitations of prior art systems.
  • aspects of the present invention relate to an engine control unit; to a vehicle; and to a method of controlling an internal combustion engine as claimed in the appended claims.
  • an engine control unit for controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the engine control unit comprising:
  • At least one processor configured to receive a first signal from a first oxygen sensor for determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter and to receive a second signal from a second oxygen sensor disposed in the exhaust system upstream of the particulate filter, the at least one processor being configured to compare the first and second signals to detect an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter;
  • a memory device having instructions stored therein and coupled to the at least one processor
  • the at least one processor is configured to control lambda ( ⁇ ) of the internal combustion engine in dependence on an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.
  • the exhaust system is connected to the internal combustion engine. In use, exhaust gas from the internal combustion engine is conveyed through the exhaust system and passes through the particulate filter.
  • the particulate filter traps carbonaceous particulate material in the exhaust gas. In order to regenerate the particulate filter, the trapped carbonaceous particulate material is oxidised and this process consumes oxygen.
  • the engine control unit may determine that oxidation is occurring in the particulate filter.
  • the engine control unit may be able to determine a rate at which oxidation is occurring in the particulate filter, for example to determine that oxidation is occurring at or above a predetermined threshold rate.
  • the at least one processor is configured to control the internal combustion engine in dependence on an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.
  • the engine control unit may control operation of the internal combustion engine to regenerate the particulate filter. More particularly, the engine control unit may control operation of the internal combustion engine such that the exhaust gases contain oxygen to oxidise carbonaceous particulate material in the particulate filter.
  • the engine control unit is operable to control the engine to promote regeneration of the particulate filter when the prevailing conditions in the particulate filter are suitable for oxidation of trapped carbonaceous particulate material.
  • the engine control unit has particular application for a gasoline engine in which gasoline (petrol) is combusted therein, typically through spark-ignition.
  • the engine control unit may be configured to operate the (gasoline) internal combustion engine under stoichiometric conditions.
  • the engine control unit may actively control the gasoline internal combustion engine to establish the conditions in the particulate filter for oxidation of the carbonaceous particulate material.
  • the control strategy described herein may reduce the frequency with which any such active regeneration events may be required.
  • the first signal from the first oxygen sensor may comprise or consist of a first oxygen content signal.
  • the at least one processor may be configured to detect changes in the oxygen content of the exhaust gas.
  • the at least one processor may be configured to increase lambda ( ⁇ ) when the comparison of the first and second signals indicates a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.
  • the at least one processor may be configured to increase lambda ( ⁇ ) when the comparison of the first and second signals indicates that the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter is less than or equal to a predefined oxygen content threshold.
  • the predefined oxygen content threshold may be defined as zero (0) or may be greater than zero (0).
  • an increase in the oxygen content of the exhaust gas downstream of the particulate filter may indicate that oxidation of the carbonaceous particulate material is no longer occurring within the particulate filter or that oxidation of the carbonaceous particulate material is reduced.
  • the at least one processor may be configured to reduce lambda ( ⁇ ) when the comparison of the first and second signals indicates an increase in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.
  • the second oxygen sensor may be referred to as an upstream oxygen sensor since it is disposed upstream of the particulate filter.
  • the exhaust system may comprise a catalyst.
  • the second oxygen sensor may be disposed between the catalyst and the particulate filter.
  • the at least one processor may be configured to control lambda ( ⁇ ) of the internal combustion engine in dependence on the detected increase or decrease in the oxygen content of the exhaust gas downstream of the particulate filter.
  • the at least one processor may be configured to control lambda ( ⁇ ) of the internal combustion engine in dependence on a change in the first signal relative to the second signal.
  • the at least one processor may be configured to control lambda ( ⁇ ) of the internal combustion engine in dependence on an increase or a decrease in the first signal relative to the second signal.
  • a vehicle comprising an engine control unit as described herein, an internal combustion engine and an exhaust system having a particulate filter, wherein a first oxygen sensor is provided in the exhaust system downstream of the particulate filter and a second oxygen sensor is provided in the exhaust system upstream of the particulate filter for determining an oxygen content of the exhaust gas.
  • the particulate filter may form part of an aftertreatment system for treating exhaust gases expelled from the internal combustion engine.
  • the first oxygen sensor may be referred to as a downstream oxygen sensor since it is disposed downstream of the particulate filter.
  • the first oxygen sensor may comprise a Heated Exhaust Gas Oxygen (HEGO) sensor.
  • HEGO Heated Exhaust Gas Oxygen
  • UHEGO Universal Heated Exhaust Gas Oxygen
  • the exhaust system may comprise a catalytic converter.
  • the catalytic converter may be disposed between the internal combustion engine and the particulate filter.
  • the second oxygen sensor may be disposed in the exhaust system between the particulate filter and the catalytic converter.
  • the second oxygen sensor may comprise a Heated Exhaust Gas Oxygen (HEGO) sensor.
  • the first oxygen sensor may be provided in a first lambda sensor disposed downstream of the particulate filter.
  • the first lambda sensor may be configured to generate a first lambda signal in dependence on a measured oxygen content of the exhaust gas.
  • the internal combustion engine may be a gasoline engine; and the particulate filter may be a gasoline particulate filter (GPF).
  • the particulate filter may be a coated gasoline particulate filter (cGPF).
  • a catalyst coating may be applied to the particulate filter.
  • the catalyst coating may comprise a three-way catalyst (TWC).
  • a method of controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system comprising:
  • the method may comprise increasing lambda ( ⁇ ) when a decrease in the oxygen content of the exhaust gas downstream of the particulate filter is identified.
  • the method may comprise reducing lambda ( ⁇ ) when an increase in the oxygen content of the exhaust gas downstream of the particulate filter is identified.
  • the method may comprise controlling lambda ( ⁇ ) of the internal combustion engine in dependence on the identified increase or decrease in the oxygen content of the exhaust gas downstream of the particulate filter.
  • the method may comprise controlling lambda ( ⁇ ) of the internal combustion engine in dependence on a change in the first signal relative to the second signal.
  • the method may comprise controlling lambda ( ⁇ ) of the internal combustion engine in dependence on an increase or a decrease in the first signal relative to the second signal.
  • an engine control unit for controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system
  • the engine control unit comprising: at least one processor configured to receive a first signal from a first oxygen sensor for determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter and to receive a second signal from a second oxygen sensor disposed in the exhaust system upstream of the particulate filter, the at least one processor being configured to compare the first and second signals to detect an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter; and a memory device having instructions stored therein and coupled to the at least one processor; wherein the at least one processor is configured to control lambda of the internal combustion engine in dependence on said first signal.
  • the at least one processor may be configured to increase lambda when the first signal indicates a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.
  • the at least one processor may be configured to increase lambda when the first signal indicates that the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter is less than or equal to a predefined oxygen content threshold.
  • the at least one processor may be configured to reduce lambda when the received first signal indicates an increase in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.
  • a vehicle comprising an engine control unit according to an aspect of the present invention, an internal combustion engine and an exhaust system having a particulate filter; wherein a first oxygen sensor is provided in the exhaust system downstream of the particulate filter for determining an oxygen content of the exhaust gas.
  • the first oxygen sensor may comprise a Heated Exhaust Gas Oxygen sensor.
  • the exhaust system may comprise a catalytic converter disposed between the internal combustion engine and the particulate filter.
  • the second oxygen sensor may be disposed in the exhaust system between the particulate filter and the catalytic converter.
  • the internal combustion engine may be a gasoline engine and the particulate filter may be a gasoline particulate filter, the particulate filter may be a coated gasoline particulate filter.
  • a method of controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system comprising: determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter; determining an oxygen content of the exhaust gas in the exhaust system upstream of the particulate filter; comparing the oxygen content of the exhaust gas upstream and downstream of the particulate filter to identify a decrease or an increase in the oxygen content of the exhaust gas downstream of the particulate filter; and controlling lambda of the internal combustion engine in dependence on the determined oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter.
  • the method may comprise increasing lambda when the determined oxygen content of the exhaust gas decreases downstream of the particulate filter.
  • the method may comprise reducing lambda when the determined oxygen content of the exhaust gas increases downstream of the particulate filter.
  • Any control unit or controller described herein may suitably comprise a computational device having one or more electronic processors.
  • the system may comprise a single control unit or electronic controller or alternatively different functions of the controller may be embodied in, or hosted in, different control units or controllers.
  • controller or “control unit” will be understood to include both a single control unit or controller and a plurality of control units or controllers collectively operating to provide any stated control functionality.
  • a suitable set of instructions may be provided which, when executed, cause said control unit or computational device to implement the control techniques specified herein.
  • the set of instructions may suitably be embedded in said one or more electronic processors. Alternatively, the set of instructions may be provided as software saved on one or more memory associated with said controller to be executed on said computational device.
  • the control unit or controller may be implemented in software run on one or more processors. One or more other control unit or controller may be implemented in software run on one or more processors, optionally the same one or more processors as the first controller. Other suitable arrangements may also be used.
  • Figure 1 shows a schematic representation of a vehicle incorporating an engine control unit in accordance with an embodiment of the present invention
  • Figure 2 is a schematic representation of the exhaust system of the vehicle shown in Figure 1 ; and Figure 3 is a series of graphs illustrating operation of the engine control unit in accordance with an aspect of the present invention.
  • a vehicle 1 in accordance with an embodiment of the present invention is illustrated in Figure 1 .
  • the vehicle 1 comprises an internal combustion engine 2 having an exhaust system 3 for conveying exhaust gas from the internal combustion engine 2.
  • the vehicle 1 in the present embodiment is an automobile, but the present invention may usefully be implemented in other types of vehicle.
  • the internal combustion engine 2 is a gasoline engine which combusts gasoline in one or more combustion chamber (not shown).
  • the internal combustion engine 2 is a gasoline light duty engine adapted to operate at stoichiometric conditions. Exhaust gases from the combustion cycle are expelled from the internal combustion engine 2 into the exhaust system 3 for treatment by aftertreatment systems (denoted by the reference numeral 4), including a catalytic converter 5 and a gasoline particulate filter (GPF) 6.
  • aftertreatment systems denoted by the reference numeral 4
  • a catalytic converter 5 and a gasoline particulate filter (GPF) 6.
  • the catalytic converter 5 is a three-way catalyst (TWC) and is operative to combine oxygen (02) with carbon monoxide (CO) and unburned hydrocarbons (UHC); and to reduce the nitrogen oxides (NOx), particularly the mono-nitrogen oxides nitric oxide (NO) and nitrogen dioxide (N02).
  • the GPF 6 collects carbonaceous particulate material from the exhaust gas.
  • the carbonaceous particulate material may comprise or consist of soot.
  • the GPF 6 in the present embodiment is a coated gasoline particulate filter (cGPF) having a catalyst coating.
  • the GPF 6 is regenerated by oxidising the trapped carbonaceous particulate material.
  • the oxidation process requires oxygen and a high temperature, for example a temperature greater than or equal to 500 °C or 600 °C.
  • the vehicle 1 comprises an engine control unit 7 for controlling operation of the internal combustion engine 2.
  • the engine control unit 7 comprises a processor 8 connected to a memory device 9.
  • the processor 8 is configured to implement a set of non-transitory computational instructions stored on said memory device 9. When executed, the computational instructions cause the processor to implement an engine control strategy for controlling operation of the internal combustion engine 2.
  • the processor 8 is configured to output a lambda control signal CON1 for controlling lambda ( ⁇ ) of the internal combustion engine 2.
  • Lambda ( ⁇ ) is the ratio of the actual air/fuel ratio (AFR) to the stoichiometric air/fuel ratio (AFR sto c /,) and is defined by the following equation: ⁇ -
  • the internal combustion engine 2 is configured to operate at stoichiometric conditions, i.e. lambda ( ⁇ ) is at least substantially equal to one (1 ).
  • the lambda control signal CON1 may increase or decrease lambda ( ⁇ ) of the internal combustion engine 2.
  • the engine control unit 7 is configured to adjust lambda ( ⁇ ) to control the oxygen content of the exhaust gas introduced into the exhaust system 3.
  • the engine control unit 7 is connected to a first oxygen sensor 10, a second oxygen sensor 1 1 and a third oxygen sensor 12.
  • the first and second oxygen sensors 10, 1 1 in the present embodiment each comprise a Heated Exhaust Gas Oxygen (HEGO) sensor (also referred to as lambda sensors or "narrow-band” sensors).
  • HEGO Heated Exhaust Gas Oxygen
  • the first oxygen sensor 10 is disposed in the exhaust system 3 downstream of the GPF 6.
  • the second oxygen sensor 1 1 is disposed in the exhaust system 3 downstream of the catalytic converter 5 and upstream of the GPF 6.
  • the third oxygen sensor 12 in the present embodiment comprises a Universal Heated Exhaust Gas Oxygen (UHEGO) sensor (also referred to as a universal lambda sensor or "wideband” sensor).
  • UHEGO Universal Heated Exhaust Gas Oxygen
  • the third oxygen sensor 12 is disposed in the exhaust system 3 between the internal combustion engine 2 and the catalytic converter 5.
  • the first oxygen sensor 10, the second oxygen sensor 1 1 and the third oxygen sensor 12 are adapted to monitor the oxygen content of the exhaust gas.
  • the first, second and third oxygen sensors 10, 1 1 , 12 are configured to output respective first, second and third oxygen content signals SIG1 , SIG2, SIG3 to the engine control unit 7.
  • the first, second and third oxygen content signals SIG1 , SIG2, SIG3 provide feedback to the engine control unit 7 which implements a closed-loop fuelling control strategy to control lambda ( ⁇ ) of the internal combustion engine 2.
  • One or more of the first, second and third oxygen content signals SIG1 , SIG2, SIG3 may be used for on-board diagnostics (OBD).
  • OBD on-board diagnostics
  • the engine control unit 7 operates in a conventional manner in dependence on said second and third oxygen content signals SIG2, SIG3.
  • the first oxygen content signal SIG1 also provides feedback to the engine control unit 7.
  • a decrease in the oxygen content of the exhaust gas downstream of the GPF 6 is an indicator that oxidation of the carbonaceous particulate material has occurred (or is occurring) within the GPF 6.
  • the engine control unit 7 is configured to adjust lambda ( ⁇ ) to promote oxidation of the carbonaceous particulate material.
  • the engine control unit 7 is configured to increase lambda ( ⁇ ). Increasing lambda ( ⁇ ) results in a lean bias being applied to the internal combustion engine 2.
  • the engine control unit 7 may control lambda ( ⁇ ) such that a predetermined oxygen content is maintained in the exhaust gas, as determined by the closed feedback loop established with the first oxygen sensor 10.
  • an increase in the oxygen content of the exhaust gas downstream of the GPF 6 is an indicator that oxidation of the carbonaceous particulate material is no longer taking place.
  • the oxidation of the carbonaceous particulate material may be complete or the temperature of the GPF 6 may have dropped.
  • the engine control unit 7 monitors the first oxygen content signal SIG1 and decreases lambda ( ⁇ ) when an increase in the oxygen content is identified.
  • the third oxygen sensor 12 and the second oxygen sensor 1 1 are operative to detect when the available oxygen is being fully used and to increase lambda ( ⁇ ) to enlean the internal combustion engine 2 accordingly. Any oxygen present in the exhaust gas downstream of the catalytic converter 5 enables a small amount of the carbonaceous particulate material in the GPF 6 to be oxidised, provided the temperature of the GPF 6 is high enough.
  • the second and third oxygen sensors 1 1 , 12 are operative actively to reduce the amount of oxygen available for oxidation of the carbonaceous particulate material in the GPF 6.
  • the engine control unit 7 can detect and react to oxygen being used for oxidation of the carbonaceous particulate material in the GPF 6.
  • the engine control unit 7 is configured to modify lambda ( ⁇ ) to increase oxidation of the carbonaceous particulate material.
  • the engine control unit 7 is configured to increase lambda ( ⁇ ) of the internal combustion engine 2 in dependence on detection of a decrease in the oxygen content of the exhaust gas downstream of the GPF 6.
  • the engine control unit 7 may thereby control the fuelling of the internal combustion engine 2 to provide overall stoichiometric conditions across the complete aftertreatment system 4. At least in certain embodiments, increasing lambda ( ⁇ ) of the internal combustion engine results in additional oxygen being contained in the exhaust gas for oxidising carbonaceous particulate material in the GPF 6. This may help to prevent carbonaceous particulate material accumulation over a wider range of duty cycles and/or may reduce the requirement/frequency of active regeneration events.
  • the maintenance of stoichiometric conditions allows for reduction of nitrogen oxides (NOx) and oxidation of carbon monoxide (CO) and hydrocarbons (HC) in the catalytic converter 5; and oxidation of the carbonaceous particulate material in the GPF 6.
  • the engine control unit 7 can be configured to improve oxidation of the carbonaceous particulate material, as well as gaseous emissions conversion, during stoichiometric operation of the internal combustion engine 2.
  • a first graph 105 shows a temperature plot for the GPF 6; a second graph 1 10 shows an oxygen content (%) of the exhaust gas downstream of the GPF 6; and a third graph 1 15 shows lambda ( ⁇ ) set by the engine control unit 7.
  • the oxidation of the carbonaceous particulate material reduces the oxygen content of the exhaust gas downstream of the GPF 6.
  • the measurement of the oxygen content by the first oxygen sensor 10 is illustrated in the second graph 1 10.
  • the engine control unit 7 controls lambda ( ⁇ ) in dependence on the first oxygen content signal SIG1 .
  • the resulting enleanment of the internal combustion engine 2 causes an increase in the oxygen content of the exhaust gas supplied to the GPF, thereby helping to promote oxidation of the carbonaceous particulate material.
  • the engine control unit 7 continues to control lambda ( ⁇ ) in dependence on the measured oxygen content of the exhaust gas downstream of the GPF 6.
  • lambda ( ⁇ ) may be controlled to maintain the oxygen content of the exhaust gas downstream of the GPF 6 substantially constant, as illustrated in the second graph 1 10 (time t2-t3).
  • lambda ( ⁇ ) may be controlled to maintain the oxygen content at a predetermined level suitable for oxidation of the carbonaceous particulate material.
  • lambda ( ⁇ ) may be controlled to increase the oxygen content of the exhaust gas downstream of the GPF 6.
  • the engine control unit 7 may detect the decrease in the oxygen content exclusively in dependence on the first oxygen content signal SIG1 .
  • the engine control unit 7 may detect the decrease in the oxygen content in dependence on the first and second oxygen content signals SIG1 , SIG2, for example by comparing the oxygen content of the exhaust gas introduced into the GPF 6 with the oxygen content of the exhaust gas exiting the GPF 6.
  • the engine control unit 7 in accordance with the present invention may improve oxidation of the carbonaceous particulate material in the GPF 6, for example during extended running without deceleration fuel shut-off.
  • the accumulation of carbonaceous particulate material in the GPF 6 may be partially or completely reduced over a wider range of duty cycles, thereby reducing the requirement/frequency of active regeneration events may also be reduced.
  • no oxygen will be consumed and the closed loop fuelling control strategy will operate as normal for the catalytic converter 5 and for the GPF 6.
  • the engine control unit 7 has been described herein as increasing lambda ( ⁇ ) of the internal combustion engine 2 in dependence on detection of a decrease in the oxygen content of the exhaust gas downstream of the GPF 6.
  • the engine control unit 7 may be configured to increase lambda ( ⁇ ) of the internal combustion engine 2 in dependence on determining that the oxygen content of the exhaust gas downstream of the GPF 6 is below a predefined oxygen content threshold.
  • the engine control unit 7 is described herein as receiving a first signal SIG1 from a first oxygen sensor 10 disposed downstream of the GPF 6.
  • the first oxygen sensor 10 may be provided in a first lambda sensor.
  • the lambda sensor may output a lambda signal to the engine control unit 7 generated in dependence on the measured oxygen content of the exhaust gas downstream of the GPF 6.
  • the engine control unit 7 may be configured to control lambda ( ⁇ ) of the internal combustion engine 2 in dependence on this lambda signal. A decrease in the measured oxygen content of the exhaust gas downstream of the GPF 6 will result in a decrease in the lambda signal. It will be understood, therefore, that the operation of the engine control unit 7 is substantially unchanged in this arrangement.
  • the engine control unit 7 may be configured to increase lambda ( ⁇ ) of the internal combustion engine 2 when the first signal SIG1 indicates a decrease in the lambda signal from the lambda sensor disposed downstream of the GPF 6.
  • the present invention has been described with particular reference to a gasoline light duty engine 2 adapted to operate at stoichiometric conditions. It will be understood that the present invention can be used in conjunction with spark-ignition internal combustion engines 2 which combust fuels other than gasoline under stoichiometric conditions.
  • the internal combustion engine 2 could be adapted to use compressed natural gas (CNG), alcohol or liquefied petroleum gas (LPG) as a fuel source.
  • CNG compressed natural gas
  • LPG liquefied petroleum gas

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Processes For Solid Components From Exhaust (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

La présente invention concerne une unité de commande (7) de moteur qui permet de commander un moteur à combustion interne (2) afin de régénérer un filtre à particules (6) disposé dans un système d'échappement (3). L'unité de commande (7) de moteur reçoit un premier signal (SIG1) d'un premier capteur d'oxygène (10) afin de déterminer une teneur en oxygène d'un gaz d'échappement dans le système d'échappement (3), en aval du filtre à particules (6). Une valeur lambda (λ) du moteur à combustion interne (2) est régulée en fonction du premier signal (SIG1). L'unité de commande (7) de moteur offre une application particulière dans la commande d'un moteur à essence. La présente invention concerne également un véhicule (1) ayant une unité de commande (7) de moteur qui permet de commander le moteur à combustion interne (2), et un procédé de commande d'un moteur à combustion interne (2).
PCT/EP2017/064375 2016-08-05 2017-06-13 Commande de moteur pour régénération de filtre à particules de gaz d'échappement WO2018024391A1 (fr)

Priority Applications (1)

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DE112017003919.3T DE112017003919T5 (de) 2016-08-05 2017-06-13 Verfahren und Vorrichtung zur Motorsteuerung

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GB1613505.5 2016-08-05
GB1613505.5A GB2552714B (en) 2016-08-05 2016-08-05 Engine control method and apparatus

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CN110685782A (zh) * 2018-07-06 2020-01-14 罗伯特·博世有限公司 用于评估尾气过滤器中的化学反应的转化速率的方法
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US10975791B1 (en) 2019-12-13 2021-04-13 Denso International America, Inc. System and method for particulate filter regeneration

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CN110318896B (zh) * 2018-03-29 2022-07-22 丰田自动车株式会社 内燃机的控制装置及方法
CN110685782A (zh) * 2018-07-06 2020-01-14 罗伯特·博世有限公司 用于评估尾气过滤器中的化学反应的转化速率的方法
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DE112017003919T5 (de) 2019-05-09
GB2552714A (en) 2018-02-07

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