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
  • F02D41/1444—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
  • F02D41/1458—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 determination means using an estimation
• • 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
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1493—Details
  • F02D41/1494—Control of sensor heater
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D18/00—Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
  • G01D18/002—Automatic recalibration
  • G01D18/006—Intermittent recalibration
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
  • G01N27/403—Cells and electrode assemblies
  • G01N27/406—Cells and probes with solid electrolytes
  • G01N27/4067—Means for heating or controlling the temperature of the solid electrolyte
• • 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
  • F02D41/0275—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 NOx trap or adsorbent
• • 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
  • F02D41/1493—Details
  • F02D41/1495—Detection of abnormalities in the air/fuel ratio feedback system

Definitions

• the present invention relates to a method for controlling the operation of a probe associated with means for purifying the exhaust gases of an internal combustion engine.
• the invention also relates to a device for controlling the operation of such a probe. Efforts are being made to reduce polluting emissions from motor vehicles fitted with internal combustion engines, in particular emissions of carbon monoxide (CO), nitrogen oxides (NOx) and unburnt hydrocarbons (HC).
• CO carbon monoxide
• NOx nitrogen oxides
• HC unburnt hydrocarbons
• the nitrogen oxides are retained in active sites of catalytic elements promoting their reaction with the reducing agents.
• Purge phases of the catalytic elements are provided in which action is taken on the fuel and molecular oxygen content of the exhaust gases to promote the elimination of emissions of nitrogen oxides trapped in catalytic sites of the catalytic elements.
• a combustion mixture is controlled and regulated by a system operating in a closed loop to obtain exhaust gases having a richness, that is to say the ratio between the mass quantity of fuel present in the exhaust gas over the mass quantity of air present in the exhaust gas divided by the ratio of the mass quantity of fuel over the mass quantity of air in stoichiometric proportion, substantially equal to or greater than 1 and a low oxygen concentration.
• the richness of the exhaust gases is checked using oxygen probes arranged on an exhaust line upstream and downstream of the purification means.
• Oxygen probes, of the proportional or all or nothing type (lambda) arranged on an exhaust line downstream of the purification means can be used directly for the control of the richness of the exhaust gases by an analysis of the composition exhaust gases having passed through the purification means or to detect an end of the reduction activity of the nitrogen oxides adsorbed on a catalyst converter.
• the dispersions may be due to a dispersion between the probes due to their manufacture or to aging of the probes.
• the dispersions are manifested by probe to probe differences in operating temperature as a function of a supply voltage, sensitivity to catalytic activity or to the diffusion of chemical species as well as sensitivity to the temperature of the exhaust gases. and the speed of the exhaust gases.
• Excessive dispersions between the probes disturb the operation of a regulation of the richness of the exhaust gases for the regeneration of catalytic converters, or a detection of an end of reduction activity of the nitrogen oxides adsorbed on a converter catalytic. Aging of a probe with significant dispersion in its measurements can render exhaust gas purification means inoperative.
• the present invention relates to a method for controlling a probe associated with exhaust gas purification means arranged on an exhaust line of an internal combustion engine making it possible to compensate for variations in an output signal from the probe due to a dispersion between the new probes, or after aging.
• the invention also relates to a method for controlling the operation of a probe associated with means for purifying the exhaust gases making it possible to detect a malfunction of the probe.
• an output signal from the probe is compared with a reference value, and action is taken on the probe to reduce a difference between the output signal and the reference value.
• An output signal from the probe depends on the operating temperature. To act on the probe, you can modify its operating temperature.
• a supply voltage j of the probe is modified, from a nominal supply voltage, in order to modify an operating temperature of the probe.
• the probe is acted on as a function of a difference between an output signal from the probe and a reference value determined during a regeneration phase of the purification means.
• the signals provided by probes located downstream of the purification means of the "nitrogen oxide trap" type present during a purging phase means for purifying similar portions whatever an operating point of the internal combustion engine.
• these similar portions differ significantly from one probe to another.
• the probe is acted on according to a difference between an output signal from the probe and a reference value determined during a final step of a regeneration phase of the purification means.
• a phase of regeneration of the purification means there is a first step corresponding to an activity of reduction of the nitrogen oxides trapped by the catalytic elements followed by a final step, when most of the nitrogen oxides adsorbed have been eliminated.
• the composition of the exhaust gases changes so that an oxygen sensor located downstream of the purification means provides an output signal having a plateau corresponding to a saturation of the sensor, with a value which does not depend on an operating point of the internal combustion engine.
• a probe failure is detected as a function of the action required on the probe to reduce the difference between the output signal and the reference value.
• the invention also relates to a device for controlling the operation of a probe associated with means for purifying the exhaust gases of an internal combustion engine, the device comprising measuring means capable of determining a difference between the signal of output of the probe and a reference value and means for controlling a supply voltage of the probe as a function of the difference between the output signal of the probe and the reference value.
• the probe is an "all or nothing" type oxygen probe disposed downstream of a catalytic converter.
• the device comprises a detection module capable of detecting stages of a regeneration phase of the exhaust gas filtering means from a signal supplied by the probe, and a measurement module capable determining the difference between the output signal of the probe and a reference value during a final step of a regeneration phase.
• - Figure 2 is a schematic view of a device for controlling the operation of a probe according to one aspect of the invention
• - Figure 3 is a graph illustrating different output signals from a probe located downstream of a catalytic converter during a purge phase.
• a drive assembly referenced 1 as a whole, is intended to be arranged in a motor vehicle, not shown, for driving the latter.
• the drive assembly 1 comprises an internal combustion engine 2 supplied with air via an intake line 3, exhaust gases being discharged into an exhaust line 4.
• the intake line 3 comprises an intake pipe 5 connected to an intake port, not shown, being provided with an intake control member of the intake butterfly type, provided for adjusting a flow rate. of admitted air, said member not being shown in the drawing.
• the intake pipe 5 is connected on the opposite side to the intake socket for the engine 2, by means of an intake manifold not shown and allowing the distribution of the intake air to different combustion chambers or cylinders of the internal combustion engine 2.
• the exhaust line 4 comprises a manifold portion 6 located at the outlet of the internal combustion engine 2 and connected to an exhaust manifold, not shown, intended to channel flows of exhaust gases from the engine cylinders or combustion chambers, a catalytic converter 7 arranged downstream of the manifold portion 6 in the direction of flow of the exhaust gases, for the treatment and purification of the gases exhaust, and an outlet pipe 8 for discharging the exhaust gases treated by the catalytic converter 7.
• the exhaust gases from the catalytic converter 7 can be discharged directly or through other means for purifying exhaust gases located downstream of the catalytic converter 7.
• the catalytic converter 7 is of the type intended for the reduction of carbon monoxide and unburnt hydrocarbons present in the exhaust gases by an oxidation-reduction reaction with the nitrogen oxides adsorbed in catalytic sites of the catalytic converter 7.
• the drive assembly 1 comprises an injection control system comprising injection control members 9, one of which is shown diagrammatically, disposed in the internal combustion engine 2.
• the injection members 9 are provided for injecting fuel into a common intake pipe or into an intake manifold, or directly into a combustion chamber.
• the injection control system comprises a first oxygen probe 10, of the lambda or proportional probe type, located on the manifold line 6 upstream of the catalytic converter 7, and a second probe 11 located on the outlet pipe.
• the injection control system comprises a control unit 12 receiving the measurement signals from the oxygen probes 10, 11 by means of transmission links for measurement signals 13 and 14 respectively, and capable of transmitting control signals to the injection members 9 via control links 15.
• the drive assembly 1 also includes a supply unit 16 for the oxygen probes 10, 11, connected to these probes
• the supply unit 16 receives a control signal from the injection control device 12 via a control link 17.
• L power supply unit 16 is connected in a non- shown to a source of electrical energy from the motor vehicle, such as a battery.
• the power supply unit 16 can be a portion of a general power supply unit intended for the electrical supply of various pieces of equipment of a motor vehicle.
• the supply unit can in particular be used to supply the injection control unit 12.
• the power supply unit 16 comprises a correction assembly 20 comprising a comparison stage 21 with two inputs and an output, and receiving the input signal SI output of the downstream probe 11 and a setpoint C.
• the comparison stage 21 determines the difference ⁇ between the setpoint C and the output signal SI by subtracting the output signal SI from the setpoint C.
• the correction set 20 also includes a correction module 22 receiving at input the difference ⁇ between the setpoint C and the output signal SI and providing at output a correction ⁇ of a supply voltage of the downstream probe 11.
• the unit of power supply 16 comprises an addition module 23 with two inputs and an output receiving as input a nominal supply voltage T nom and the supply voltage correction ⁇ .
• the addition module 23 adds the nominal supply voltage T nom and the supply voltage correction ⁇ to obtain at output a corrected voltage T corr used for supplying the downstream probe.
• the injection control unit 12 comprises a detection module 24 designed to detect different stages of a regeneration or purge phase of the catalytic converter 7, receiving as input the output signal SI from the downstream probe 11 and supplying output a step signal transmitted via the link 17 to the correction unit 20 of the power supply unit 16.
• the power supply unit 16 comprises a diagnostic module
• a graph includes an abscissa axis X on which the time is plotted and an ordinate axis Y on which is plotted an output voltage of the downstream probe 11.
• An output signal SI from the downstream probe 11, shown in solid lines, is substantially constant and equal to 0 before an initial instant T1 and after a final instant T2 corresponding respectively to the start and to the end of a purge phase of the converter catalytic 7.
• the signal SI rises rapidly to reach a first plateau PI at a first value of output voltage NI and substantially retains this first value VI until an intermediate instant T3.
• the output signal SI increases rapidly to reach a second plateau P2 at a second output voltage value N2 and substantially retains this second value V2 until the final instant T2.
• the signal SI drops rapidly to reach the value 0.
• the downstream probe 11 delivers a signal proportional to the fuel richness of the exhaust gases which can be used for regulating this fuel richness of the exhaust gases, for example by means of fuel injection members in the combustion of the internal combustion engine 2.
• the jump between the first plateau PI and the second plateau P2 makes it possible to detect the end of the purging of the nitrogen oxides and the passage to a final stage of a purging phase. Indeed, it will be possible to detect the crossing of a threshold of the first derivative of the signal SI at time T3, a cancellation of the second derivative of the signal SI substantially at time T3, or even to detect the crossing of a threshold by the difference between the value of the instantaneous signal and the sliding average value of the signal SI.
• the detection module 24 of the injection control unit 12 allows the detection of the first and second stages of a regeneration phase as indicated above, from an output signal SI from the downstream probe 11.
• the purge is stopped after detection of the jump so that the time interval [Tl T3] is generally less than the time interval [T3 T2] which is short.
• the time interval [T3 T2] has been exaggerated relative to the time interval [Tl T3].
• a signal S3 shown in dotted lines is similar to the signal SI except that the first plateau value is substantially greater than the first value VI while the second plateau value and equal to the second plateau value V2 of the signal SI.
• the signal S3 corresponds to a different operating point of the internal combustion engine 2 for which the composition of the exhaust gases may be different, which explains a difference in the output signal during the step of elimination of nitrogen oxides , between the initial instant Tl and the intermediate instant T3.
• the second plateau P2 corresponds to saturation of the downstream probe 11, and, for a probe at a given operating temperature, the second value V2 is substantially equal regardless of an operating point of the engine. But the second value V2 differs between probes for which there is a dispersion, whatever the origin of the dispersion (manufacture, aging ...) and its manifestation (variation in the operating temperature as a function of a voltage d 'food, different sensitivity ).
• a signal S2 shown in dashed lines in FIG. 3, of general shape similar to the signal S I represents a signal showing a dispersion which may be due to aging of the probe or to a dispersion between new probes.
• the signal S2 has first and second plates with values of the output signal significantly lower than the first and second values VI, V2. If there is a dispersion in the measurement signals produced by the probe with respect to measurements on which is based a regulation of a composition of the exhaust gases with a view to regeneration of means for purifying the exhaust gases , the regulation is disturbed and a jump detection can also be disturbed.
• a downstream probe 11 is acted on so as to obtain, during a final step of a regeneration phase, an output signal SI having a second plateau value V2 substantially equal to a setpoint C.
• the comparison stage of the correction unit 20 of the power supply unit 16 compares the setpoint C with the value of the output signal SI and determines the deviation ⁇ .
• the correction module 22 of the correction assembly 20 determines a correction ⁇ of the supply voltage of the downstream probe 11, this correction ⁇ being determined to obtain the corrected voltage d supply of the downstream probe 11.
• the correction module 22 may include stages for regulating the proportional integral or derivative type or any other regulation stage adapted to allow an effective correction to be calculated.
• the modification of the supply voltage of the downstream probe 11 causes a modification of its operating temperature.
• the output signal SI of the downstream probe 11 whether it is an all-or-nothing or proportional type probe, depends on its operating temperature.
• the correction assembly 20 makes it possible to form a loop for regulating the supply voltage of the probe and therefore the operating temperature of the downstream probe 11 to correct the value of the output signal SI during a final step of a purge phase of the catalytic converter 7.
• the correction unit 20 When leaving a final regeneration step, the correction unit 20 is informed by the detection module 24 of the injection control unit 12, and the correction module 20 delivers a correction ⁇ which corresponds to the correction provided during the previous final regeneration step.
• the correction ⁇ is determined by the regulation loop of the output signal SI of the downstream probe 11 during the final stages of the regeneration phases, for which the value V2 which we should substantially know would have to be reached if it did not exist dispersion between new or used probes.
• the final stages of the regeneration phase constitute learning stages making it possible to know the correction ⁇ to be applied permanently.
• the correction is determined sequentially by successive learnings.
• the diagnostic module 25 outputs an alert signal, for example an alert signal which can be read by a diagnostic device implemented by an operator or an alert signal leading to a signal emitted on a dashboard of the motor vehicle, for example using an indicator light.
• a control method is obtained which makes it possible to act on a probe located downstream of the exhaust gas purification means to compensate for dispersions which may appear between the probes or following an aging of the probe, for better operation and better control of the purification means.
• the method also makes it possible to detect a failure of the probe, with a view to its replacement.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Physics & Mathematics (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Molecular Biology (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Exhaust Gas After Treatment (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=32338904

Family Applications (1)

Country Status (5)

Citations (1)

Family Cites Families (6)

• 2002
  • 2002-12-17 FR FR0216021A patent/FR2848608B1/fr not_active Expired - Fee Related
• 2003
  • 2003-12-17 EP EP03813625A patent/EP1573275A2/de not_active Withdrawn
  • 2003-12-17 US US10/539,590 patent/US7230210B2/en not_active Expired - Fee Related
  • 2003-12-17 JP JP2004561558A patent/JP4248497B2/ja not_active Expired - Fee Related
  • 2003-12-17 WO PCT/FR2003/003765 patent/WO2004057277A2/fr not_active Ceased

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