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
  • 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
  • F01N3/2033—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using a fuel burner or 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
  • F01N3/18—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
• • 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
  • F01N11/007—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus
• • 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
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
  • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• • 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

Definitions

• the invention relates to a method for checking a burner system for heating an exhaust gas catalytic converter according to the preamble of patent claim 1.
• the pollutant emission of an internal combustion engine can be effectively reduced by catalytic aftertreatment with the aid of a three-way catalytic converter in connection with an ambda control device.
• An important prerequisite for this, however, is that both the lambda probe of the control device and the catalytic converter have reached their operating temperatures. In order to bring these two components of the exhaust gas purification system to their operating temperature quickly, various heating measures have already been proposed.
• the burner is arranged directly in front of the catalytic converter.
• the fuel will fed to the burner from the distributor rail of the fuel circuit of the internal combustion engine and the air necessary for combustion contributes to the secondary air blower, which is often already standard.
• Such a secondary air blower is conventionally used to blow air into the exhaust pipe of the internal combustion engine near the exhaust valves in order to achieve pre-oxidation of the exhaust gases.
• the invention is therefore based on the object of specifying a checking method for an internal combustion engine with a burner system mentioned at the outset for heating an exhaust gas catalytic converter, which allows a simple statement to be made about the functionality of the burner in a simple manner.
• the air ratio of the burner is used as a criterion for the functionality of the burner and this air ratio is derived from the signal positions of two lambda probes, one of which is arranged upstream of the catalytic converter in front of the burner and the other behind the catalytic converter and the anyway in modern internal combustion engines for on-board diagnosis of exhaust-relevant parts. are available, there is a low-cost and therefore inexpensive way of assessing the burner in terms of its proper function.
• FIG. 1 shows a simplified block diagram of an internal combustion engine with a catalytic converter that can be heated by means of a burner and a lambda probe in front of and behind the catalytic converter
• FIG. 2 shows a selection of time-dependent signal profiles when the method according to the invention is carried out.
• Block diagram shows only those parts that are necessary for understanding the method according to the invention.
• the reference numeral 10 denotes an internal combustion engine with an intake line 11 and an exhaust line 12.
• An air mass meter 13 arranged in the intake line 11 measures the air mass drawn in by the internal combustion engine 10.
• the air mass meter can be implemented as a hot wire or hot film air mass meter.
• a first oxygen sensor in the form of a lambda probe LSI is inserted in the exhaust gas line 12 upstream of a three-way catalytic converter 14 used to convert the constituents HC, CO and NO x contained in the exhaust gas of the internal combustion engine 10, which sensor outputs an output signal ULS1 as a function of the residual oxygen content in the exhaust gas outputs to an electronic control device 16 of the internal combustion engine 10.
• a second lambda probe LS2 is provided in the further course of the exhaust line 12, which outputs an output signal ULS2 depending on the residual oxygen content of the exhaust gas after cleaning by the catalyst 14.
• the lambda probe indicates a rich or lean mixture
• the output voltage of the lambda probe has a value assumes that represents a rich or a lean mixture composition.
• the lambda sensor LSI arranged in front of the catalytic converter 14 serves in a conventional manner as a control element for the lambda control of the fuel-air mixture of the internal combustion engine, it is possible to evaluate both the lambda sensor LSI in front of the catalytic converter 14 by evaluating the output signals ULS1 also the
• Output signals ULS2 of the lambda probe LS2 after the catalyst 14 possible to check the functionality or the efficiency of the catalyst 14.
• the difference between the output signals of the two probes (DE 38 30 515 AI) or the time delay between the output signals of the two probes for switching from rich to lean or vice versa can be used as a measure of the catalyst efficiency (DE 41 01 616 AI ).
• a sensor 18 for detecting the engine speed and a coolant temperature sensor 19 are provided at suitable points of the internal combustion engine 10.
• the exits of the sensors mentioned are connected via interfaces to corresponding inputs of the electronic control device 16 for the internal combustion engine 10.
• Such electronic control devices for internal combustion engines which, in addition to fuel injection, can also take on a multitude of other tasks, including the on-board diagnosis of exhaust-gas-relevant components, are known per se, so that in the following only in connection with the structure and mode of operation of the present invention is dealt with.
• the heart of the electronic control device 16 is a microcomputer which controls the required functions according to a defined program.
• the electronic control device 16 controls the required functions according to a defined program.
• the fuel for the internal combustion engine 10 is then injected into the intake line 11 with the aid of one or more injection valves 20.
• This burner 24, which via a line 26 having a fuel shut-off valve 25 with fuel of the internal combustion engine 10 is supplied consists essentially of a combustion chamber with a burner nozzle and an ignition device. The burner nozzle is supplied with the burner air conveyed by the secondary air pump 21, as well as the fuel made available from the fuel circuit of the internal combustion engine.
• the ignition device comprises ignition electrodes which extend into the combustion chamber and which are ignited by the electronic control device 16 with ignition pulses.
• Further components of the burner system such as metering valves, air shut-off valves and pressure regulators, have been left out for reasons of clarity and are also not necessary for understanding the method according to the invention.
• the detailed structure of such a burner system and its control can be found, for example, in document DE 41 32 814 AI.
• the internal combustion engine 10 is started and both the secondary air pump 21 and the ignition of the burner 24 are switched on via corresponding signals from the electronic control device 16. Since the secondary air pump 22 requires a certain start-up time until the air required for combustion is available in the combustion chamber of the burner 24, the fuel for the burner 24 is only available after the time delay T_BR at the time t1 (FIG. 2, burner start) by opening the fuel cut-off valve 25 released. During this time, the secondary air supply and the ignition device of the burner 24 are monitored in a manner known per se, for example by checking the secondary voltage of the ignition device. If this check reveals that there is faulty ignition or no or insufficient secondary air, then the fuel supply to the burner 24 remains interrupted.
• both the ignition and the secondary air supply to the burner have been recognized as being in order, the fuel supply to the burner is switched on. After the fuel has been switched on, the combustion process is monitored with the aid of the ignition voltage on the spark plugs of the burner.
• both La bda sensors LSI, LS2 are operated with maximum heating power from the engine start (time tO). If a clocked activation of the probe heaters is used, this means that the two lambda probes LSI, LS2 are activated with a 100% duty cycle.
• both lambda probes are heated to their operating temperature and are therefore ready to produce an output signal rich / lean according to the To discharge residual oxygen content in the exhaust gas before and after the three-way catalytic converter 14 of the internal combustion engine 10.
• the diagnosis of the burner-air ratio is only started after the time T_LD at time t2, if in addition to the conditions already mentioned, no diagnosis errors of the two lambda probes, the lambda control device or the long-term adaptation are stored. For this purpose, the content of an error memory 27 contained in the electronic control device 16 is read out and evaluated accordingly.
• burner lambda ⁇ gR At the beginning of the diagnosis (time t2) of the burner air ratio, hereinafter also referred to as burner lambda ⁇ gR, four different ones are used depending on the values of the output signals ULS1, ULS2 of the two lambda sensors LSI, LS2 Differentiated cases:
• the lambda probe LSI in front of the catalytic converter shows a lean mixture (air ratio ⁇ uLs ⁇ > -00) and
• the lambda probe LS2 after the catalytic converter also shows a lean mixture (air ratio ⁇ LS2 l-00)
• the lambda sensor LSI in front of the catalytic converter shows fat -
• the lambda probe LSI in front of the catalytic converter shows a rich mixture (air ratio ⁇ u J s ⁇ ⁇ l-00) and
• the lambda probe LS2 after the catalytic converter also shows a rich mixture (air ratio ⁇ u J g 2 ⁇ 1.00)
• the lambda probe LSI in front of the catalytic converter shows a rich mixture (air ratio ⁇ jLs ⁇ ⁇ 1.00)
• the lambda probe LSI in front of the catalytic converter shows lean mixture (air ratio ⁇ uLg ⁇ > l.0) and - the lambda probe LS2 after the catalytic converter shows rich mixture (air ratio ⁇ j ⁇ J s2 ⁇ 1 • 0) •
• TI_BR new TI_BR old + TI_BR IC .
• TI_BRJJJC represents a fixed amount by which the value of the enrichment factor is increased per specified time unit.
• the enrichment is ended when either the output signals ULS1, ULS2 of the two lambda probes LSI, LS2 signal a rich mixture, or when a predetermined limit value TI_BR_MAX has been reached for the enrichment, regardless of whether the two lambda probes have already recognized a rich mixture or not. In both cases, the enrichment factor TI_BR is then reset to a value of 1.0.
• the output signal ULS1 of the lambda probe LSI does not jump from its initial state, which signals a lean mixture, to a state which represents a rich mixture, it can be assumed that either an error in the air ratio of the engine supplied to the internal combustion engine There is a mixture or a fault in the La bda probe LSI. In this case, the diagnosis is aborted and repeated the next time the burner is started and no entry is made in the error memory 27.
• the values TI_F1, TI_F2 are temporarily stored in a memory 28 of the electronic control device 16.
• the time T_SU is positive if first the lambda probe LSI and then the lambda probe LS2 indicate rich mixture (example according to FIG. 2, case 1) and the time T_SU is negative if the lambda probe LS2 and only then does the LSI lambda probe display a rich mixture.
• the enrichment factor TI_F2 in which the lambda probe LS2 indicates a rich mixture, is corrected according to the following relationship:
• TI_FK2 TI_F2 - (TI_F2 - TI_F1) * TI_LS / TI_SU,
• TI_FK2 denotes the corrected enrichment factor
• T_LS a dead time that takes the gas running time between the two probes into account.
• the air ratio of the burner (burner lambda) ⁇ g R can be determined:
• ⁇ .. ML - BKM + ⁇ i FAK2 * TI FK2 - TI FAK ⁇ * TI l) +1 HR ML_ BR * ⁇ 4.1 ⁇ ⁇ ⁇
• ML_BKM Air mass flow that is supplied to the internal combustion engine during the diagnosis (determined by the air mass meter)
• ML_BR Air mass flow that is supplied to the burner during the diagnosis (fixed predetermined value)
• TI_FAK1,2 Total of the other, applied in the electronic engine control for warming up the internal combustion engine
• the result of the check can be communicated acoustically and / or visually to the driver of the vehicle and when the internal combustion engine is started again 10 the heating of the catalyst can be suppressed by means of the burner.
• the fuel-air mixture of the internal combustion engine 10 is emaciated.
• the reduction is also carried out via the factor TI_BR, which is gradually reduced from the value 1.0 according to the following relationship:
• TI_BR new TI_BR old - TI_BR INC .
• the emaciation is ended when either both lambda probes have detected lean or when a predefined limit value is reached
• TI_BR_MIN for the thinning is reached, regardless of whether the two lambda probes have already recognized a lean mixture or not. In both cases, the TI BR factor is then reset to a value of 1.0.
• the lambda probe LSI does not reach a voltage jump during the thinning, it can be assumed that there is either an error in the air ratio of the mixture supplied to the internal combustion engine or an error in the lambda probe LSI. In this case the diagnosis is aborted and repeated the next time the burner is started. There is no entry in the error memory 27.
• the lambda probes LSI, LS2 show different mixture compositions before the diagnosis begins, ie the lambda probe LSI shows a rich mixture, while the lambda probe LS2 shows lean mixture (case 3) or vice versa (case 4), Since the diagnosis described in case 1 can only be carried out with rectified probe signals, the state of the signal of the lambda sensor LSI can be changed by emaciation (case 3) or enrichment (case 4) of the fuel-air mixture of the internal combustion engine . This takes place with an accumulation or enrichment function, as was explained on the basis of the two cases 1 and 2.
• the diagnosis is terminated. If the lambda probe LS 1 in front of the catalytic converter indicates the same mixture composition as the lambda probe LS 2 after the catalytic converter within the limit value by leaning or enriching, the further diagnosis is carried out as in the case of cases 1 and 2 described method.

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

Applications Claiming Priority (3)

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• 1994
  • 1994-09-30 DE DE4435196A patent/DE4435196C1/de not_active Expired - Fee Related
• 1995
  • 1995-09-22 KR KR1019960702835A patent/KR960706602A/ko not_active Application Discontinuation
  • 1995-09-22 JP JP8511266A patent/JP2819068B2/ja not_active Expired - Lifetime
  • 1995-09-22 EP EP95932615A patent/EP0731876A1/de not_active Withdrawn
  • 1995-09-22 WO PCT/DE1995/001316 patent/WO1996010685A1/de not_active Application Discontinuation
• 1996
  • 1996-05-30 US US08/656,418 patent/US5634330A/en not_active Expired - Fee Related

Non-Patent Citations (1)

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