JP2012241608A - Diagnostic apparatus for deterioration in catalyst in fuel-reforming system for internal combustion engine - Google Patents

Diagnostic apparatus for deterioration in catalyst in fuel-reforming system for internal combustion engine Download PDF

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JP2012241608A
JP2012241608A JP2011112142A JP2011112142A JP2012241608A JP 2012241608 A JP2012241608 A JP 2012241608A JP 2011112142 A JP2011112142 A JP 2011112142A JP 2011112142 A JP2011112142 A JP 2011112142A JP 2012241608 A JP2012241608 A JP 2012241608A
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fuel
catalyst
reforming
deterioration
temperature
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Hiroyuki Inuzuka
寛之 犬塚
Makoto Miwa
真 三輪
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Denso Corp
株式会社デンソー
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/002Monitoring 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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D19/00Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/06Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/0623Failure diagnosis or prevention; Safety measures; Testing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D19/00Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/06Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/0663Details on the fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02D19/0668Treating or cleaning means; Fuel filters
    • F02D19/0671Means to generate or modify a fuel, e.g. reformers, electrolytic cells or membranes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/35Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/36Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with means for adding fluids other than exhaust gas to the recirculation passage; with reformers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/45Sensors specially adapted for EGR systems
    • F02M26/46Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/45Sensors specially adapted for EGR systems
    • F02M26/46Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition
    • F02M26/47Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition the characteristics being temperatures, pressures or flow rates
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/49Detecting, diagnosing or indicating an abnormal function of the EGR system
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/30Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a fuel reformer
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/04Methods of control or diagnosing
    • F01N2900/0411Methods of control or diagnosing using a feed-forward control
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06Parameters used for exhaust control or diagnosing
    • F01N2900/14Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1404Exhaust gas temperature
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/30Use of alternative fuels
    • Y02T10/36Multiple fuels, e.g. multi fuel engines
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/40Engine management systems
    • Y02T10/47Exhaust feedback

Abstract

PROBLEM TO BE SOLVED: To diagnose deterioration in a fuel-reforming catalyst while satisfying a cost reduction request, in a system including a function for reforming fuel to be supplied to an engine.SOLUTION: A diagnostic apparatus for deterioration in a catalyst in a fuel reforming system includes: an inlet-side temperature sensor 30 for detecting a temperature at an inlet side of a fuel reforming catalyst 28; and an outlet-side temperature sensor 31 for detecting a temperature at an outlet side of the fuel-reforming catalyst 28. In a reforming driving mode, an ECU 34 opens an EGR valve 25 to recirculate a part of exhaust gas into an intake side as EGR gas, and a reforming-fuel injection valve 26 injects a reforming fuel into the EGR gas. The fuel-reforming catalyst 28 executes reforming control to reform the fuel into a fuel having high-combustibility. A differential temperature between the catalyst outlet-side temperature detected by the outlet-side temperature sensor 31 and the catalyst inlet-side temperature detected by the inlet-side temperature sensor 30 is calculated during the execution of the reforming control and compared with a deterioration-determination threshold, whereby deterioration diagnosis can be performed to determine whether the fuel-reforming catalyst 28 is deteriorated.

Description

本発明は、内燃機関に供給される燃料を改質する機能を備えた内燃機関の燃料改質システムの触媒劣化診断装置に関する発明である。 The present invention is an invention relates to a catalyst deterioration diagnosis device for a fuel reforming system for an internal combustion engine having a function of reforming the fuel supplied to the internal combustion engine.

内燃機関に改質した燃料を供給する技術としては、例えば、特許文献1(特開2004−218548号公報)に記載されているように、燃料タンク内の燃料を燃料噴射弁に供給する燃料供給通路の途中に、燃料を改質するためのヒータや改質触媒を備えた改質器を配置するようにしたものがある。 As a technique for supplying fuel which is modified into an internal combustion engine, for example, as described in Patent Document 1 (JP 2004-218548), a fuel supply fuel in the fuel tank to the fuel injection valve supply in the middle of the passage, there is that to arrange the reformer with a heater and reforming catalyst for reforming the fuel.

このような改質器を備えたシステムでは、改質器に異常(例えば改質触媒の劣化)が発生して燃料を正常に改質できなくなると、内燃機関の燃焼状態が悪化する可能性があるため、改質器の異常が発生した場合には、その異常を早期に検出することが好ましい。 In systems with such a reformer, the abnormality in the reformer (e.g. deterioration of the reforming catalyst) can not be properly reformed fuel is generated, is a possibility that the combustion state of the internal combustion engine deteriorate some reason, when the abnormality of the reformer has occurred, it is preferable to detect the abnormality in an early stage.

そこで、上記特許文献1では、改質器の異常により燃料の改質状態(例えば高沸点成分の含有割合)が変化すると、燃料の物性(比重や蒸気圧)が変化することに着目して、改質器の下流側に、改質器から送り出された燃料を貯溜する貯溜タンクを設けると共に、この貯溜タンク内の燃料の物性(比重又は蒸気圧)を検出するセンサを設け、このセンサで検出した燃料の物性を基準値と比較して改質器(改質触媒等)の異常の有無を判定するようにしている。 Therefore, in Patent Document 1, when the reformed abnormal state by the fuel reformer (e.g., the content of high-boiling components) is changed, the physical properties of the fuel (specific gravity and vapor pressure) in view of the changes, downstream of the reformer, provided with a reservoir tank for reserving the fuel fed from the reformer, a sensor for detecting the physical properties of the fuel in the reservoir tank (gravity or vapor pressure), detected by the sensor physical properties of the fuel compared with a reference value and so as to determine the presence or absence of abnormality of the reformer (reforming catalyst or the like) that.

特開2004−218548号公報 JP 2004-218548 JP

しかし、上記特許文献1の異常診断技術では、改質器から送り出された燃料を貯溜する貯溜タンクを設ける必要があると共に、この貯溜タンク内の燃料の物性(例えば比重)を検出する特殊なセンサを設ける必要があるため、近年の重要な技術的課題である低コスト化の要求を満たすことができないという欠点がある。 However, the abnormality diagnosis technique of Patent Document 1, the it is necessary to provide a reservoir tank for reserving the fuel fed from the reformer, a special sensor for detecting the physical properties of the fuel in the reservoir tank (e.g., specific gravity) it is necessary to provide a, there is a disadvantage that it can not meet the demands of cost reduction, which is an important technical problem in recent years.

そこで、本発明が解決しようとする課題は、低コスト化の要求を満たしながら、燃料改質触媒の劣化診断を行うことができる内燃機関の燃料改質システムの触媒劣化診断装置を提供することにある。 Therefore, an object of the present invention is to provide, to provide while meeting the demands of cost reduction, the catalyst deterioration diagnosis device for a fuel reforming system for an internal combustion engine capable of performing the deterioration diagnosis of the fuel reforming catalyst is there.

上記課題を解決するために、請求項1に係る発明は、内燃機関の吸気系に供給される媒体ガス中に改質用の燃料を噴射する改質用燃料噴射手段と、媒体ガス中の燃料を改質する燃料改質触媒とを備えた内燃機関の燃料改質システムの触媒劣化診断装置において、燃料改質触媒での反応熱量の情報を検出する反応熱量情報検出手段と、この反応熱量情報検出手段で検出した反応熱量の情報に基づいて燃料改質触媒の劣化診断を行う触媒劣化診断手段とを備えた構成としたものである。 In order to solve the above problems, the invention includes a reforming fuel injection means for injecting fuel for reforming the medium gas supplied to the intake system of an internal combustion engine, the fuel in the medium gas according to claim 1 in the catalyst deterioration diagnosis device for a fuel reforming system for an internal combustion engine equipped with a fuel reforming catalyst for reforming, and reaction heat information detecting means for detecting information of the reaction heat of the fuel reforming catalyst, the reaction heat information it is obtained by that a catalyst deterioration diagnosis means for performing deterioration diagnosis of the fuel reforming catalyst based on the detected information of the reaction heat by the detection means configured.

燃料改質触媒が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒での反応熱量(発熱量又は吸熱量)が減少するため、燃料改質触媒での反応熱量の情報を用いれば、燃料改質触媒の劣化の有無を判定する劣化診断を行うことができる。 When deterioration of the fuel reforming catalyst, as compared to normal (when no degradation), since the reaction heat of the fuel reforming catalyst (heating value or heat absorption amount) is reduced, the information of the reaction heat of the fuel reforming catalyst the use, it is possible to determine deterioration diagnosing the presence or absence of deterioration of the fuel reforming catalyst. しかも、従来技術のように燃料を貯溜する貯溜タンクや燃料の物性を検出する特殊なセンサ等を設けるといった必要が無いため、近年の重要な技術的課題である低コスト化の要求を満たすことができる。 Moreover, since there is no need such provide a special sensor for detecting the physical properties of the storage tank or fuel reservoir of the fuel or the like as in the prior art, to meet the demand for cost reduction which is a significant technical challenge in recent years it can.

この場合、請求項2のように、反応熱量情報検出手段として、燃料改質触媒の入口側の温度(以下「触媒入口側温度」という)を検出する入口側温度検出手段と、燃料改質触媒の出口側の温度(以下「触媒出口側温度」という)を検出する出口側温度検出手段とを備え、触媒劣化診断手段は、燃料改質触媒で燃料を改質する改質制御の実行中に入口側温度検出手段で検出した触媒入口側温度と出口側温度検出手段で検出した触媒出口側温度とに基づいて燃料改質触媒の劣化診断を行うようにしても良い。 In this case, as in claim 2, as the reaction heat information detecting means, an inlet-side temperature detection means for detecting the temperature of the inlet side of the fuel reforming catalyst (hereinafter referred to as "catalyst inlet side temperature"), the fuel reforming catalyst the outlet temperature (hereinafter referred to as "catalyst outlet temperature") and a outlet temperature detection means for detecting the catalyst deterioration diagnosis means, the fuel in the fuel reforming catalyst during reforming control to modify it may be the deterioration diagnosis of the fuel reforming catalyst based on the catalyst outlet temperature detected by the catalyst inlet-side temperature and the outlet temperature detection means detected by the inlet-side temperature detection means.

燃料改質触媒が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒での反応熱量が減少して、改質制御の実行中の触媒入口側温度と触媒出口側温度との関係が正常時とは異なってくるため、改質制御の実行中に検出した触媒入口側温度と触媒出口側温度とを用いれば、燃料改質触媒の劣化の有無を精度良く判定することができる。 When deterioration of the fuel reforming catalyst, as compared to normal (when no degradation), reaction heat of the fuel reforming catalyst is reduced, the catalyst inlet-side temperature and the catalyst outlet temperature in the reforming control execution since the relationship becomes different from that during normal, using a catalyst inlet-side temperature and the catalyst outlet temperature detected during the execution of the modification control, the presence or absence of deterioration of the fuel reforming catalyst can be accurately determined .

或は、請求項3のように、反応熱量情報検出手段として、燃料改質触媒の温度(以下「触媒温度」という)又は燃料改質触媒の出口側の温度(以下「触媒出口側温度」という)を検出する温度検出手段を備え、触媒劣化診断手段は、燃料改質触媒で燃料を改質する改質制御の開始前に温度検出手段で検出した触媒温度又は触媒出口側温度と改質制御の開始後に温度検出手段で検出した触媒温度又は触媒出口側温度とに基づいて燃料改質触媒の劣化診断を行うようにしても良い。 Alternatively, as claimed in claim 3, as the reaction heat information detecting means, the temperature of the fuel reforming catalyst (hereinafter "catalyst temperature" hereinafter) that or the fuel reforming catalyst outlet temperature (hereinafter "catalyst outlet temperature" ) includes a temperature detecting means for detecting the catalyst deterioration diagnosis means, the fuel reforming catalyst fuel catalyst temperature or catalyst outlet temperature and the reforming control detected by the temperature detection means before the start of the reforming control to modify the in starting later may be the deterioration diagnosis of the fuel reforming catalyst on the basis of the catalyst temperature or catalyst outlet temperature detected by the temperature detecting means.

燃料改質触媒が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒での反応熱量が減少して、改質制御の開始前の触媒温度又は触媒出口側温度と改質制御の開始後の触媒温度又は触媒出口側温度との関係が正常時とは異なってくるため、改質制御の開始前に検出した触媒温度又は触媒出口側温度と改質制御の開始後に検出した触媒温度又は触媒出口側温度とを用いれば、燃料改質触媒の劣化の有無を精度良く判定することができる。 When the fuel reforming catalyst is degraded, as compared to normal (when no degradation), reaction heat of the fuel reforming catalyst is reduced, the reforming control start before the catalyst temperature or catalyst outlet temperature and the reforming control catalysts since the temperature or the relationship between the catalyst outlet temperature differs from the normal, the catalyst detected after the start of the catalyst temperature or catalyst outlet temperature and the reforming control was detected before the start of the modification control after the start the use of a temperature or catalyst outlet temperature, the presence or absence of deterioration of the fuel reforming catalyst can be accurately determined.

しかしながら、本発明は、改質制御の開始後(つまり改質制御の実行中)に温度検出手段で検出した触媒温度又は触媒出口側温度に基づいて燃料改質触媒の劣化診断を行うようにしても良い。 However, the present invention is, after the start of reforming control (i.e. running modification control) and to perform the deterioration diagnosis of the fuel reforming catalyst based on the catalyst temperature or catalyst outlet temperature detected by the temperature detecting means it may be.

また、請求項4のように、内燃機関の燃焼状態の情報を検出する燃焼状態情報検出手段と、この燃焼状態情報検出手段で検出した燃焼状態の情報に基づいて燃料改質触媒の劣化診断を行う触媒劣化診断手段とを備えた構成としても良い。 Moreover, as of claim 4, the combustion state information detecting means for detecting information on the combustion state of the internal combustion engine, the deterioration diagnosis of the fuel reforming catalyst on the basis of the information of the combustion state detected by the combustion state information detecting means a catalyst deterioration diagnosis means that performs may be configured to include. 燃料改質触媒が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒による燃料の改質度合が低下して、内燃機関の燃焼状態が変化するため、燃焼状態の情報を用いれば、燃料改質触媒の劣化の有無を判定する劣化診断を行うことができる。 When deterioration of the fuel reforming catalyst, as compared to normal (when no degradation), modification degree of the fuel by the fuel reforming catalyst is lowered, for changing the combustion state of the internal combustion engine, which uses the information of the combustion state if, it is possible to perform the determining deterioration diagnosing the presence or absence of deterioration of the fuel reforming catalyst.

この場合、請求項5のように、触媒劣化診断手段は、燃料改質触媒で燃料を改質する改質制御の開始前に燃焼状態情報検出手段で検出した燃焼状態の情報と改質制御の開始後に燃焼状態情報検出手段で検出した燃焼状態の情報とに基づいて燃料改質触媒の劣化診断を行うようにしても良い。 In this case, as in claim 5, the catalyst deterioration diagnosis means, the combustion state detected by the combustion state information detecting means before the start of the reforming control for reforming fuel in the fuel reforming catalyst information and a reforming control may be the deterioration diagnosis of the fuel reforming catalyst on the basis of the combustion state information of the detected combustion state detection means information after the start. 燃料改質触媒が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒による燃料の改質度合が低下して、改質制御の開始前の燃焼状態と改質制御の開始後の燃焼状態との関係が正常時とは異なってくるため、改質制御の開始前に検出した燃焼状態の情報と改質制御の開始後に検出した燃焼状態の情報とを用いれば、燃料改質触媒の劣化の有無を精度良く判定することができる。 When deterioration of the fuel reforming catalyst, as compared to normal (when no degradation), reduced reforming the degree of fuel by the fuel reforming catalyst, after the start before the start of the combustion state and the reforming control reforming control for the relationship between the combustion state becomes different from that during normal, using the combustion state detected after the start of the information and the reforming control of the combustion state detected before the start of the modification control information, the fuel reforming the presence or absence of deterioration of the catalyst can be accurately determined.

しかしながら、本発明は、改質制御の開始後(つまり改質制御の実行中)に燃焼状態情報検出手段で検出した燃焼状態の情報に基づいて燃料改質触媒の劣化診断を行うようにしても良い。 However, the present invention can be carried out degradation diagnosis of the fuel reforming catalyst on the basis of the information of the combustion state detected by the combustion state information detecting means after the start of reforming control (i.e. in the modified control execution) good.

更に、請求項6のように、燃焼状態情報検出手段は、燃焼状態の情報として、燃焼安定性指標、着火遅れ期間、主燃焼期間、燃焼重心、筒内圧力最大値、EGR限界、燃焼速度のうちの少なくとも一つを検出するようにすると良い。 Furthermore, as in claim 6, the combustion state information detecting means, as the information of the combustion state, the combustion stability index, the ignition delay period, the main combustion period, the combustion center of gravity, cylinder pressure maximum value, EGR limit, the burning rate among the good so as to detect at least one. これらのパラメータは、いずれも内燃機関の燃焼状態を精度良く反映した情報となる。 These parameters are all the accurately reflects information the combustion state of the internal combustion engine.

また、請求項7のように、燃料改質触媒の出口側で燃料の改質度合を検出する改質度合検出手段と、この改質度合検出手段で検出した燃料の改質度合に基づいて燃料改質触媒の劣化診断を行う触媒劣化診断手段とを備えた構成としても良い。 Also, as in claim 7, a reforming degree detecting means for detecting the modification degree of the fuel at the outlet side of the fuel reforming catalyst, based on the modification degree of the fuel detected by the reforming degree detecting means fuel it may be configured to include a catalyst deterioration diagnosis means for performing deterioration diagnosis of the reforming catalyst. 燃料改質触媒が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒による燃料の改質度合が低下するため、燃料の改質度合を用いれば、燃料改質触媒の劣化の有無を判定する劣化診断を行うことができる。 When deterioration of the fuel reforming catalyst, as compared to normal (when no degradation), the modification degree of the fuel by the fuel reforming catalyst is reduced, the use of the reformed degree of fuel, the fuel reforming catalyst deterioration whether it is possible to perform the deterioration diagnosis determines.

この場合、請求項8のように、触媒劣化診断手段は、燃料改質触媒で燃料を改質する改質制御の開始前に改質度合検出手段で検出した燃料の改質度合と改質制御の開始後に改質度合検出手段で検出した燃料の改質度合とに基づいて燃料改質触媒の劣化診断を行うようにしても良い。 In this case, as according to claim 8, the catalyst deterioration diagnosis means, the fuel detected by the reforming degree detecting means before the start of the reforming control for reforming fuel in the fuel reforming catalyst reforming degree and reforming control starting later may be the deterioration diagnosis of the fuel reforming catalyst on the basis of the modification degree of the fuel detected by the reforming degree detecting means. 燃料改質触媒が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒による燃料の改質度合が低下して、改質制御の開始前の燃料の改質度合と改質制御の開始後の燃料の改質度合との関係が正常時とは異なってくるため、改質制御の開始前に検出した燃料の改質度合と改質制御の開始後に検出した燃料の改質度合とを用いれば、燃料改質触媒の劣化の有無を精度良く判定することができる。 When the fuel reforming catalyst is degraded, as compared to normal (when no degradation), reduced reforming the degree of fuel by the fuel reforming catalyst, the reforming degree and reforming control of the fuel before the start of the reforming control reforming the degree of the fuel after the start for the relationship between the reforming degree becomes different from that during normal, fuel was detected after the start of the modification degree and the modification control of the fuel that has been detected prior to the start of the reforming control using the preparative, the presence or absence of deterioration of the fuel reforming catalyst can be accurately determined.

しかしながら、本発明は、改質制御の開始後(つまり改質制御の実行中)に改質度合検出手段で検出した燃料の改質度合に基づいて燃料改質触媒の劣化診断を行うようにしても良い。 However, the present invention is to perform the deterioration diagnosis of the fuel reforming catalyst on the basis of the modification degree of the fuel detected after the start of reforming controlled (i.e. during the reforming control run) in the reforming degree detecting means it may be.

また、燃料改質触媒によって燃料を水素濃度の高い状態に改質するシステムの場合、請求項9のように、改質度合検出手段は、燃料の改質度合として水素濃度を検出する水素センサを用いるようにしても良い。 Further, when the fuel by the fuel reforming catalyst system for reforming the hydrogen rich conditions, as claimed in claim 9, modified degree detecting means, the hydrogen sensor that detects the hydrogen concentration as a modifying degree of the fuel it may be used. このようにすれば、燃料の改質度合(水素濃度)を精度良く検出することができる。 In this way, reforming the degree of the fuel (hydrogen concentration) can be accurately detected.

図1は本発明の実施例1におけるエンジン制御システムの概略構成を示す図である。 Figure 1 is a diagram showing a schematic configuration of an engine control system according to a first embodiment of the present invention. 図2は実施例1(発熱反応触媒の場合)の劣化診断方法を説明するタイムチャートである。 Figure 2 is a time chart for explaining the degradation diagnostic method of Example 1 (the case of exothermic reaction catalyst). 図3は実施例1(吸熱反応触媒の場合)の劣化診断方法を説明するタイムチャートである。 Figure 3 is a time chart for explaining the degradation diagnostic method of Example 1 (the case of endothermic reaction catalyst). 図4は実施例1(発熱反応触媒の場合)の触媒劣化診断ルーチンの処理の流れを示すフローチャートである。 Figure 4 is a flowchart showing a process flow of the catalyst deterioration diagnosis routine of Example 1 (the case of exothermic reaction catalyst). 図5は改質用燃料の噴射量と劣化判定閾値との関係を説明する図である。 Figure 5 is a view for explaining the relationship between the deterioration determination threshold value and the injection quantity of fuel reforming. 図6はEGRガス流量と劣化判定閾値との関係を説明する図である。 6 is a view for explaining the relationship between the EGR gas flow rate and the deterioration determination threshold. 図7は実施例1(吸熱反応触媒の場合)の触媒劣化診断ルーチンの処理の流れを示すフローチャートである。 Figure 7 is a flowchart showing a process flow of the catalyst deterioration diagnosis routine of Example 1 (the case of endothermic reaction catalyst). 図8は実施例1(発熱反応触媒の場合)の触媒劣化診断の実行例を説明するタイムチャートである。 Figure 8 is a time chart for explaining the example of executing the catalyst deterioration diagnosis of Example 1 (the case of exothermic reaction catalyst). 図9は実施例1(吸熱反応触媒の場合)の触媒劣化診断の実行例を説明するタイムチャートである。 Figure 9 is a time chart for explaining the example of executing the catalyst deterioration diagnosis of Example 1 (the case of endothermic reaction catalyst). 図10は実施例2におけるエンジン制御システムの概略構成を示す図である。 Figure 10 is a diagram showing a schematic configuration of an engine control system in the second embodiment. 図11は実施例2の劣化診断方法を説明するタイムチャートである。 Figure 11 is a time chart for explaining the degradation diagnostic method of Example 2. 図12は実施例2の触媒劣化診断ルーチンの処理の流れを示すフローチャートである。 Figure 12 is a flowchart showing a process flow of the catalyst deterioration diagnosis routine in the second embodiment. 図13は実施例2の触媒劣化診断の実行例を説明するタイムチャートである。 Figure 13 is a time chart for explaining the example of executing the catalyst deterioration diagnosis of Example 2. 図14は実施例3におけるエンジン制御システムの概略構成を示す図である。 Figure 14 is a diagram showing a schematic configuration of an engine control system in the third embodiment. 図15は実施例3の劣化診断方法を説明するタイムチャートである。 Figure 15 is a time chart for explaining the degradation diagnosis method of Example 3. 図16は実施例3の触媒劣化診断ルーチンの処理の流れを示すフローチャートである。 Figure 16 is a flowchart showing a process flow of the catalyst deterioration diagnosis routine in the third embodiment. 図17は実施例3の触媒劣化診断の実行例を説明するタイムチャートである。 Figure 17 is a time chart for explaining the example of executing the catalyst deterioration diagnosis of the third embodiment.

以下、本発明を実施するための形態を具体化した幾つかの実施例を説明する。 Hereinafter will be described several embodiments embodying the embodiments of the present invention.

本発明の実施例1を図1乃至図9に基づいて説明する。 Example 1 of the present invention will be described with reference to FIGS. 1-9.
まず、図1に基づいてエンジン制御システム全体の概略構成を説明する。 First, a schematic configuration of an engine control system with reference to FIG.

内燃機関であるエンジン11の吸気管12の最上流部には、エアクリーナ13が設けられ、このエアクリーナ13の下流側に、モータ等によって開度調節されるスロットルバルブ14が設けられている。 In the most upstream portion of an intake pipe 12 of an internal combustion engine 11, an air cleaner 13 is provided on the downstream side of the air cleaner 13, a throttle valve 14 that is opening adjustment is provided by a motor or the like.

更に、スロットルバルブ14の下流側には、サージタンク15が設けられている。 Further, on the downstream side of the throttle valve 14, a surge tank 15 is provided. このサージタンク15には、エンジン11の各気筒に空気を導入する吸気マニホールド16が設けられ、各気筒の吸気マニホールド16に接続された吸気ポート(図示せず)又はその近傍に、それぞれ吸気ポートに燃料を噴射する燃料噴射弁17が取り付けられている。 This surge tank 15, an intake manifold 16 for introducing air is provided to each cylinder of the engine 11, connected to the intake port to the intake manifold 16 of each cylinder (not shown) or near each intake port fuel injection valve 17 for injecting fuel is attached. また、エンジン11のシリンダヘッドには、各気筒毎に点火プラグ18が取り付けられ、各点火プラグ18の火花放電によって筒内の混合気に着火される。 The cylinder head of the engine 11, the ignition plug 18 is attached to each cylinder to ignite air-fuel mixture in the cylinder by a spark discharge of the spark plug 18.

一方、エンジン11の排気管19には、排出ガスを浄化する三元触媒等の触媒20が設けられ、この触媒20の上流側と下流側に、それぞれ排出ガスの空燃比又はリッチ/リーン等を検出する排出ガスセンサ21,22(空燃比センサ、酸素センサ等)が設けられている。 On the other hand, the exhaust pipe 19 of the engine 11, the catalyst 20 is provided such as a three-way catalyst for purifying exhaust gas, upstream and downstream of the catalyst 20, the air-fuel ratio or rich / lean like each exhaust gas exhaust gas sensor 21 (air-fuel ratio sensor, an oxygen sensor) for detecting are provided.

このエンジン11には、排出ガスの一部をEGRガスとして吸気側へ還流させるEGR装置23が搭載されている。 The engine 11 is, EGR device 23 for recirculating to the intake side part of the exhaust gas as EGR gas is mounted. このEGR装置23は、排気管19のうちの触媒20の上流側と吸気管12のうちのスロットルバルブ14の下流側との間にEGR配管24が接続され、このEGR配管24に、排出ガス還流量(外部EGR量)を調整するEGR弁25が設けられている。 The EGR device 23, EGR pipe 24 is connected between the downstream side of the throttle valve 14 of the upstream intake pipe 12 of the catalyst 20 of the exhaust pipe 19, to the EGR pipe 24, instead of exhaust gas EGR valve 25 for adjusting the flow rate (external EGR amount) is provided.

更に、EGR配管24には、EGRガス(媒体ガス)中に改質用の燃料を噴射する改質用燃料噴射弁26(改質用燃料噴射手段)を備えた燃料噴射装置27と、EGRガス中の燃料を改質する燃料改質触媒28を備えた燃料改質器29が設けられている。 Further, the EGR pipe 24 includes a fuel injector 27 having the reforming fuel injection valve 26 (reforming fuel injection means) for injecting fuel for reforming the EGR gas (medium gases), EGR gas the fuel reformer 29 with a fuel reforming catalyst 28 for reforming is provided a fuel in. この燃料改質触媒28での反応熱量の情報を検出する反応熱量情報検出手段として、燃料改質触媒28の入口側のEGRガスの温度(以下「触媒入口側温度」という)を検出する入口側温度センサ30(入口側温度検出手段)と、燃料改質触媒28の出口側のEGRガスの温度(以下「触媒出口側温度」という)を検出する出口側温度センサ31(出口側温度検出手段)とが設けられている。 As reaction heat information detecting means for detecting information of a reaction heat at the fuel reforming catalyst 28, the inlet side to detect the inlet side of the EGR gas temperature of the fuel reforming catalyst 28 (hereinafter referred to as "catalyst inlet side temperature") temperature sensor 30 (the inlet side temperature detection means), an outlet side of the EGR gas temperature of the fuel reforming catalyst 28 (hereinafter referred to as "catalyst outlet temperature") outlet temperature sensor 31 for detecting the (outlet temperature detecting means) door is provided. 各気筒の燃料噴射弁17と改質用燃料噴射弁26には、共通の燃料タンク(図示せず)から燃料が供給される。 The fuel injection valve 17 and the reforming fuel injection valve 26 of each cylinder, fuel is supplied from a common fuel tank (not shown).

また、エンジン11には、吸入空気量を検出するエアフローメータ32や、クランク軸(図示せず)が所定クランク角回転する毎にパルス信号を出力するクランク角センサ33等が設けられ、このクランク角センサ33の出力信号に基づいてクランク角やエンジン回転速度が検出される。 Further, the engine 11, and an air flow meter 32 for detecting an intake air quantity, a crank shaft (not shown) such as a crank angle sensor 33 which outputs a pulse signal per rotation predetermined crank angle is provided, the crank angle a crank angle and the engine rotational speed is detected based on the output signal of the sensor 33.

これら各種センサの出力は、電子制御ユニット(以下「ECU」と表記する)34に入力される。 The outputs of these various sensors, (referred to as the "ECU") electronic control unit is input to 34. このECU34は、マイクロコンピュータを主体として構成され、内蔵されたROM(記憶媒体)に記憶された各種のエンジン制御用のプログラムを実行することで、エンジン運転状態に応じて、燃料噴射量、点火時期、スロットル開度(吸入空気量)等を制御する。 The ECU34 includes a microcomputer as a main component, by executing a built-in ROM (storage medium) in the stored various programs for the engine control, according to the engine operating state, fuel injection amount, ignition timing , it controls the throttle opening (intake air amount) and the like.

また、ECU34は、エンジン11の運転状態が所定の改質運転領域(例えば低回転・低負荷運転領域)のときに、通常運転モードから改質運転モードに切り換える。 Further, ECU 34, when the operating state of the engine 11 is predetermined reforming operating region (e.g. low rotation and low-load operating region), switching from the normal operation mode to the reforming operation mode. この改質運転モードでは、EGR弁25を開弁して排出ガスの一部をEGRガスとして吸気側へ還流させながら、改質用燃料噴射弁26でEGRガス中に改質用の燃料を噴射して気化させ、燃料改質触媒28でEGRガス中の燃料を燃焼性の高い状態(例えば水素濃度の高い状態)に改質する改質制御を実行することで、改質された燃料をエンジン11の吸気管12に供給する。 In the reforming operation mode, under reflux to the intake side as EGR gas part of the exhaust gas by opening the EGR valve 25, injects fuel for reforming the EGR gas in the reforming fuel injection valve 26 to vaporize, by executing the modified control for reforming fuel in the EGR gas in the fuel reforming catalyst 28 in the high flammability conditions (e.g. hydrogen rich state), the engine of reformed fuel 11 supplied to the intake pipe 12 of the.

燃料改質触媒28が発熱反応触媒の場合、ECU34は、後述する図4の触媒劣化診断ルーチンを実行することで、改質制御の実行中に出口側温度センサ31で検出した触媒出口側温度と入口側温度センサ30で検出した触媒入口側温度との温度差を所定の劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定する劣化診断を行う。 If the fuel reforming catalyst 28 is an exothermic reaction catalyst, ECU 34 also executes the catalyst deterioration diagnosis routine of FIG. 4 to be described later, and the catalyst outlet temperature detected by the outlet temperature sensor 31 in the modification control performed the temperature difference between the inlet side temperature sensor 30 detects the catalyst inlet side temperature is compared with a predetermined deterioration determination threshold performs determining deterioration diagnosing the presence or absence of deterioration of the fuel reforming catalyst 28.

図2に示すように、燃料改質触媒28が発熱反応触媒の場合、燃料改質触媒28が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒28での発熱量が減少して、改質制御の実行中の触媒入口側温度に対する触媒出口側温度の上昇具合が正常時とは異なってくるため、改質制御の実行中に検出した触媒出口側温度と触媒入口側温度との温度差を劣化判定閾値と比較すれば、燃料改質触媒28の劣化の有無を精度良く判定することができる。 As shown in FIG. 2, when the fuel reforming catalyst 28 is an exothermic reaction catalyst, when the fuel reforming catalyst 28 is deteriorated, as compared to normal (when no degradation), the amount of heat generated by the fuel reforming catalyst 28 is reduced and, since the rising degree of the catalyst outlet temperature to the catalyst inlet-side temperature in the reforming control execution differs from that during normal, the catalyst outlet temperature and the catalyst inlet-side temperature detected during the reforming control execution in comparison with the deterioration determination threshold temperature difference between the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

以下、燃料改質触媒28が発熱反応触媒の場合にECU34が実行する図4の触媒劣化診断ルーチンの処理内容を説明する。 Hereinafter, the fuel reforming catalyst 28 explains a procedure of the catalyst deterioration diagnosis routine of FIG. 4 which ECU34 takes when the exothermic reaction catalyst.

図4に示す触媒劣化診断ルーチンは、ECU34の電源オン期間中(イグニッションスイッチのオン期間中)に所定周期で繰り返し実行され、特許請求の範囲でいう触媒劣化診断手段としての役割を果たす。 Catalyst deterioration diagnosis routine shown in FIG. 4 is executed repeatedly at a predetermined cycle during the power-on period of the ECU 34 (during the on-time of the ignition switch), serving as a catalyst deterioration diagnosis means in the appended claims. 本ルーチンが起動されると、まず、ステップ101で、改質運転モードであるか否かを判定し、改質運転モードではない(つまり通常運転モードである)と判定された場合には、ステップ102以降の処理を行うことなく、本ルーチンを終了する。 When this routine is started, first, at step 101, when it is determined whether the modified operating mode, is determined not modified operation mode (that is, the normal operation mode), step without performing 102 subsequent processes to end the routine.

一方、上記ステップ101で、改質運転モードであると判定された場合には、ステップ102以降の処理を次のようにして実行する。 On the other hand, at step 101, if it is determined that the reforming operation mode, step 102 and subsequent processing performed in the following manner. まず、ステップ102で、EGR弁25を開弁して排出ガスの一部をEGRガスとして吸気側へ還流させるようにした後、ステップ103に進み、改質用燃料噴射弁26でEGRガス中に改質用の燃料を噴射して気化させるようにして、燃料改質触媒28でEGRガス中の燃料を燃焼性の高い状態に改質する改質制御を実行する。 First, in step 102, a portion of the exhaust gas by opening the EGR valve 25 after such recirculates to the intake side as EGR gas, the process proceeds to step 103, the EGR gas in the reforming fuel injection valve 26 so as to vaporize by injecting fuel for reforming, it executes modifying control for reforming fuel in the EGR gas in the fuel reforming catalyst 28 in the high combustion state. この際、改質用燃料の噴射量とEGRガス流量(例えばEGR弁25の開度)は、それぞれエンジン運転状態(例えばエンジン回転速度やエンジン負荷等)に応じてマップ等により算出される。 At this time, the injection amount and the EGR gas flow rate of the fuel reforming (e.g. opening degree of the EGR valve 25) is calculated by using a map or the like in accordance with each engine operating state (e.g. engine speed and engine load, etc.).

この後、ステップ104に進み、入口側温度センサ30で検出した触媒入口側温度と出口側温度センサ31で検出した触媒出口側温度を読み込んだ後、ステップ105に進み、改質用燃料の噴射量とEGRガス流量に応じた劣化判定閾値をマップ等により算出する。 Thereafter, the process proceeds to step 104, after reading the inlet side catalyst inlet side temperature detected by the temperature sensor 30 and a catalyst outlet temperature detected by the outlet temperature sensor 31, the process proceeds to step 105, the injection amount of the fuel reforming and it is calculated by using a map or the like the degradation determination threshold value corresponding to the EGR gas flow rate. 燃料改質触媒28が発熱反応触媒の場合、劣化判定閾値のマップは、例えば、改質用燃料の噴射量が多くなるほど劣化判定閾値が大きくなる(図5参照)と共に、EGRガス流量が多くなるほど劣化判定閾値が大きくなる(図6参照)ように設定されている。 If the fuel reforming catalyst 28 is an exothermic reaction catalyst, map deterioration determination threshold, for example, the deterioration determination threshold as the injection amount of the fuel reforming increases increases with (see Fig. 5), as the EGR gas flow rate increases deterioration determination threshold increases are set as (see FIG. 6). 更に、触媒入口側温度に応じて劣化判定閾値を補正するようにしても良い。 Furthermore, it is also possible to correct the deterioration determination threshold according to the catalyst inlet side temperature.

この後、ステップ106に進み、触媒出口側温度と触媒入口側温度との温度差が劣化判定閾値以上であるか否かを判定する。 Then, the procedure proceeds to step 106, determines whether the temperature difference between the catalyst outlet temperature and the catalyst inlet-side temperature is deterioration determination threshold value or higher. このステップ106で、触媒出口側温度と触媒入口側温度との温度差が劣化判定閾値以上であると判定された場合には、ステップ107に進み、燃料改質触媒28の劣化無し(正常)と判定して、本ルーチンを終了する。 In this step 106, if the temperature difference between the catalyst outlet temperature and the catalyst inlet-side temperature is determined to be deterioration determination threshold value or more, the process proceeds to step 107, without deterioration of the fuel reforming catalyst 28 (the normal) determination is made, the routine is terminated.

これに対して、上記ステップ106で、触媒出口側温度と触媒入口側温度との温度差が劣化判定閾値よりも小さいと判定された場合には、ステップ108に進み、燃料改質触媒28の劣化有り(異常)と判定して、ステップ109に進み、フェールセーフ処理を実行する。 In contrast, at step 106, if the temperature difference between the catalyst outlet temperature and the catalyst inlet-side temperature is determined to be smaller than the deterioration determination threshold value, the process proceeds to step 108, deterioration of the fuel reforming catalysts 28 There it is determined that (abnormal), the process proceeds to step 109, it executes the fail-safe process. このフェールセーフ処理では、EGR弁25の開度を減少させてEGRガス流量を減量すると共に、改質用燃料噴射弁26による改質用燃料の噴射を停止して、燃料の改質を禁止する。 In the fail-safe process, it reduces the opening degree of the EGR valve 25 as well as reduction of the EGR gas flow rate, to stop the injection of reforming fuel by the reforming fuel injection valve 26, to prohibit the modification of the fuel .

一方、燃料改質触媒28が吸熱反応触媒の場合、ECU34は、後述する図7の触媒劣化診断ルーチンを実行することで、改質制御の実行中に出口側温度センサ31で検出した触媒出口側温度と入口側温度センサ30で検出した触媒入口側温度との温度差を所定の劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定する劣化診断を行う。 On the other hand, when the fuel reforming catalyst 28 is an endothermic reaction catalyst, ECU 34 also executes the catalyst deterioration diagnosis routine of FIG. 7 to be described later, catalyst outlet side detected by the outlet temperature sensor 31 in the modification control performed the temperature difference between the temperature and the inlet side temperature sensor 30 detects the catalyst inlet side temperature is compared with a predetermined deterioration determination threshold performs determining deterioration diagnosing the presence or absence of deterioration of the fuel reforming catalyst 28.

図3に示すように、燃料改質触媒28が吸熱反応触媒の場合、燃料改質触媒28が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒28での吸熱量が減少して、改質制御の実行中の触媒入口側温度に対する触媒出口側温度の低下具合が正常時とは異なってくるため、改質制御の実行中に検出した触媒出口側温度と触媒入口側温度との温度差を劣化判定閾値と比較すれば、燃料改質触媒28の劣化の有無を精度良く判定することができる。 As shown in FIG. 3, when the fuel reforming catalyst 28 is an endothermic reaction catalyst, the fuel reforming catalyst 28 is deteriorated, as compared to normal (when no degradation), the endothermic amount of the fuel reforming catalysts 28 are reduced and, since the reduction degree of the catalyst outlet temperature to the catalyst inlet-side temperature in the reforming control execution differs from that during normal, the catalyst outlet temperature and the catalyst inlet-side temperature detected during the reforming control execution in comparison with the deterioration determination threshold temperature difference between the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

以下、燃料改質触媒28が吸熱反応触媒の場合にECU34が実行する図7の触媒劣化診断ルーチンの処理内容を説明する。 Hereinafter, the fuel reforming catalyst 28 explains a procedure of the catalyst deterioration diagnosis routine of FIG. 7 ECU34 takes when the endothermic reaction catalyst. 尚、図7のルーチンは、図4のルーチンのステップ106の処理をステップ106aの処理に変更したものである。 Note that the routine of FIG. 7, a modification of the process of step 106 in the routine of FIG. 4 to the process of step 106a.

本ルーチンでは、ステップ101で、改質運転モードであると判定された場合に、ステップ102に進み、EGR弁25を開弁した後、ステップ103に進み、改質用燃料噴射弁26で改質用の燃料を噴射して、燃料改質触媒28でEGRガス中の燃料を改質する改質制御を実行する。 In this routine, at step 101, if it is determined that the reforming operation mode, the process proceeds to step 102, after opening the EGR valve 25, the flow proceeds to step 103, reforming the reforming fuel injection valve 26 by injecting fuel in use, the fuel reforming catalyst 28 executes modification control for reforming fuel in the EGR gas.

この後、ステップ104に進み、触媒入口側温度と触媒出口側温度を読み込んだ後、ステップ105に進み、改質用燃料の噴射量とEGRガス流量に応じた劣化判定閾値をマップ等により算出する。 Then, the procedure proceeds to step 104, after reading the catalyst inlet-side temperature and the catalyst outlet temperature, the flow proceeds to step 105, is calculated by using a map or the like the degradation determination threshold value corresponding to the injection amount and the EGR gas flow rate of the fuel reforming . 燃料改質触媒28が吸熱反応触媒の場合、劣化判定閾値のマップは、例えば、改質用燃料の噴射量が多くなるほど劣化判定閾値が小さくなると共に、EGRガス流量が多くなるほど劣化判定閾値が小さくなるように設定されている。 If the fuel reforming catalyst 28 is an endothermic reaction catalyst, the map of the deterioration determination threshold, for example, with the more deterioration determination threshold injection amount of the fuel reforming is increased becomes smaller, the higher the deterioration determination threshold EGR gas flow rate increases decreases It is set to be. 更に、触媒入口側温度に応じて劣化判定閾値を補正するようにしても良い。 Furthermore, it is also possible to correct the deterioration determination threshold according to the catalyst inlet side temperature.

この後、ステップ106aに進み、触媒出口側温度と触媒入口側温度との温度差が劣化判定閾値以下であるか否かを判定する。 Then, the procedure proceeds to step 106a, and determines whether or not the temperature difference between the catalyst outlet temperature and the catalyst inlet-side temperature is less deterioration determination threshold. このステップ106aで、触媒出口側温度と触媒入口側温度との温度差が劣化判定閾値以下であると判定された場合には、ステップ107に進み、燃料改質触媒28の劣化無し(正常)と判定して、本ルーチンを終了する。 In this step 106a, if the temperature difference between the catalyst outlet temperature and the catalyst inlet-side temperature is determined to be less deterioration determination threshold value, the process proceeds to step 107, without deterioration of the fuel reforming catalyst 28 (the normal) determination is made, the routine is terminated.

これに対して、上記ステップ106aで、触媒出口側温度と触媒入口側温度との温度差が劣化判定閾値よりも大きいと判定された場合には、ステップ108に進み、燃料改質触媒28の劣化有り(異常)と判定して、ステップ109に進み、フェールセーフ処理(EGRガス流量を減量すると共に改質用燃料の噴射を停止して燃料の改質を禁止する処理)を実行する。 In contrast, in step 106a, if the temperature difference between the catalyst outlet temperature and the catalyst inlet-side temperature is determined to be larger than the deterioration determination threshold value, the process proceeds to step 108, deterioration of the fuel reforming catalysts 28 There it is determined that (abnormal), the process proceeds to step 109, it executes the fail-safe processing (processing to stop the injection of reforming fuel to prohibit modification of the fuel as well as reduced the EGR gas flow rate).

図8及び図9を用いて本実施例1の触媒劣化診断の実行例を説明する。 The execution of the catalyst deterioration diagnosis of the first embodiment will be described with reference to FIGS.
図8及び図9に示すように、通常運転モードから改質運転モードに切り換えられたときに、EGR弁25を開弁して排出ガスの一部をEGRガスとして吸気側へ還流させながら、改質用燃料噴射弁26でEGRガス中に改質用の燃料を噴射して、燃料改質触媒28でEGRガス中の燃料を燃焼性の高い状態に改質する改質制御を実行する。 As shown in FIGS. 8 and 9, when switched from the normal operation mode to the reforming operation mode, under reflux to the intake side as EGR gas part of the exhaust gas by opening the EGR valve 25, Kai by injecting fuel for reforming the EGR gas quality fuel injection valve 26, to perform the reforming control for reforming fuel in the EGR gas in the fuel reforming catalyst 28 in the high combustion state.

本実施例1では、この改質制御の実行中に出口側温度センサ31で検出した触媒出口側温度と入口側温度センサ30で検出した触媒入口側温度との温度差を算出し、この温度差を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定する劣化診断を行うようにしたので、燃料改質触媒28の劣化の有無を精度良く判定することができる。 In the first embodiment, calculates the temperature difference between the catalyst inlet-side temperature detected by the catalyst outlet temperature and the inlet side temperature sensor 30 detected by the outlet temperature sensor 31 in the modification control performed, the temperature difference since was to perform the determining deterioration diagnosing the presence or absence of degradation as compared to the degradation determination threshold fuel reforming catalyst 28, the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined. しかも、従来技術のように燃料を貯溜する貯溜タンクや燃料の物性を検出する特殊なセンサ等を設けるといった必要が無いため、近年の重要な技術的課題である低コスト化の要求を満たすことができる。 Moreover, since there is no need such provide a special sensor for detecting the physical properties of the storage tank or fuel reservoir of the fuel or the like as in the prior art, to meet the demand for cost reduction which is a significant technical challenge in recent years it can.

また、図8及び図9に破線で示すように、燃料改質触媒28の劣化診断機能を備えていないシステムでは、燃料改質触媒28の劣化が発生しても、それを検出できず、燃料改質触媒28の劣化発生時にフェールセーフ処理を実施できないため、エンジン11の燃焼状態が悪化してトルク変動が発生してドライバビリティが悪化する可能性がある。 Further, as shown by broken lines in FIGS. 8 and 9, in a system without a deterioration diagnosis function of the fuel reforming catalyst 28, deterioration of the fuel reforming catalyst 28 occurs, it can not detect it, fuel since when degradation occurs of the reforming catalyst 28 can not implement the fail-safe process, drivability combustion state and the torque variation is generated by deterioration of the engine 11 is likely to deteriorate.

これに対して、本実施例1では、改質制御の実行中に検出した触媒出口側温度と触媒入口側温度との温度差を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定し、燃料改質触媒28の劣化有りと判定された場合には、フェールセーフ処理(EGRガス流量を減量すると共に改質用燃料の噴射を停止して燃料の改質を禁止する処理)を実行するようにしたので、エンジン11の燃焼状態の悪化を抑制してトルク変動の発生を抑制することができ、ドライバビリティの悪化を防止することができる。 In contrast, in Example 1, the presence or absence of deterioration of the fuel reforming catalyst 28 the temperature difference between the catalyst outlet temperature and the catalyst inlet-side temperature detected during the reforming control execution as compared with the deterioration determination threshold value determines, when it is determined that there is deterioration of the fuel reforming catalysts 28, fail-safe processing (processing for prohibiting modification of the fuel by stopping the injection of reforming fuel with weight loss the EGR gas flow rate) since so as to run, to suppress the deterioration of the combustion state of the engine 11 it is possible to suppress the occurrence of torque fluctuation, it is possible to prevent deterioration in drivability.

尚、上記実施例1では、改質制御の実行中に検出した触媒出口側温度と触媒入口側温度との温度差を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしたが、劣化診断方法は、これに限定されず、適宜変更しても良く、例えば、改質制御の実行中に検出した触媒出口側温度と触媒入口側温度との温度比を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしても良い。 Note that determines the presence or absence of deterioration of Example 1, a fuel reforming catalyst 28 the temperature difference between the catalyst outlet temperature detected during the reforming control execution and catalyst inlet side temperature as compared with the deterioration determination threshold value as to the but degradation diagnostic method is not limited thereto, may be appropriately changed, for example, the deterioration determination of the temperature ratio of the catalyst outlet temperature detected during the reforming control execution and catalyst inlet side temperature threshold value may be determined whether the deterioration of the fuel reforming catalyst 28 in comparison.

また、改質制御の開始前に検出した触媒出口側温度と改質制御の開始後に検出した触媒出口側温度との温度差又は温度比を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしても良い。 Further, deterioration of the fuel reforming catalyst 28 in comparison with the deterioration determination threshold temperature difference or temperature ratio of the catalyst outlet temperature detected after the start of the catalyst outlet temperature and the reforming control detected before the start of the modification control the presence or absence of may be determined. 或は、燃料改質触媒28の温度(触媒温度)を検出する触媒温度センサを設け、改質制御の開始前に検出した触媒温度と改質制御の開始後に検出した触媒温度との温度差又は温度比を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしても良い。 Alternatively, the catalyst temperature sensor for detecting the temperature of the fuel reforming catalyst 28 (catalyst temperature) is provided, the temperature difference between the catalyst temperature detected after the start of the catalyst temperature and the reforming control detected before the start of the modification control or it may be in the temperature ratio compared with the deterioration determination threshold to determine the presence or absence of deterioration of the fuel reforming catalysts 28.

燃料改質触媒28が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒28での反応熱量が減少して、改質制御の開始前の触媒温度又は触媒出口側温度と改質制御の開始後の触媒温度又は触媒出口側温度との関係が正常時とは異なってくるため、改質制御の開始前に検出した触媒温度又は触媒出口側温度と改質制御の開始後に検出した触媒温度又は触媒出口側温度とを用いれば、燃料改質触媒28の劣化の有無を精度良く判定することができる。 When the fuel reforming catalyst 28 is deteriorated, as compared to normal (when no degradation), reaction heat of the fuel reforming catalyst 28 is reduced, before the start of the reforming control catalyst temperature or catalyst outlet temperature and the reforming because the relationship between the catalyst temperature or catalyst outlet temperature after the start of the quality control becomes different from that during normal, the catalyst temperature or the catalyst outlet temperature and the reforming control after starting the detection was detected before the start of the modification control by using the catalyst temperature or the catalyst outlet temperature, the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

しかしながら、本発明は、改質制御の開始後(つまり改質制御の実行中)に検出した触媒温度又は触媒出口側温度を劣化判定値と比較して燃料改質触媒28の劣化の有無を判定するようにしても良い。 However, the present invention determines the presence or absence of deterioration of the fuel reforming catalyst 28 in comparison with the deterioration determining value detected catalyst temperature or catalyst outlet temperature after the start of the reforming control (i.e. in the modified control execution) it may be.

次に、図10乃至図13を用いて本発明の実施例2を説明する。 Next, a second embodiment of the present invention will be described with reference to FIGS. 10 to 13. 但し、前記実施例1と実質的に同一部分については説明を省略又は簡略化し、主として前記実施例1と異なる部分について説明する。 However, the for the substantially same parts as in Example 1 was omitted or simplified, mainly described in Example 1 and different parts.

本実施例2では、図10に示すように、エンジン11のシリンダヘッドには、各気筒毎(又は特定の気筒のみ)に燃焼状態を検出する燃焼状態検出センサとして、各気筒毎(又は特定の気筒のみ)に筒内圧力を検出する筒内圧力センサ35が設けられている。 In the second embodiment, as shown in FIG. 10, the cylinder head of the engine 11, as the combustion state detection sensor for detecting the combustion state of each cylinder (or a specific cylinder only), each cylinder (or specific cylinder pressure sensor 35 for detecting the cylinder pressure in the cylinder only) is provided. この筒内圧力センサ35は、点火プラグ18と一体化したタイプのものを用いても良いし、点火プラグ18とは別体で取り付けるタイプのものを用いても良い。 The cylinder pressure sensor 35 may be used of the type integrated with an ignition plug 18, the ignition plug 18 may be used of the type attached separately. 尚、温度センサ30,31を省略した構成としても良い。 It may be configured to omit the temperature sensor 30, 31.

また、本実施例2では、ECU34により後述する図12の触媒劣化診断ルーチンを実行することで、改質制御の実行中に筒内圧力センサ35の出力に基づいてエンジン11の燃焼状態の情報である燃焼パラメータを算出(検出)し、この燃焼パラメータを所定の劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定する劣化診断を行う。 In the second embodiment, by executing the catalyst deterioration diagnosis routine of FIG. 12 to be described later by ECU 34, the information of the combustion state of the engine 11 based on the output of the cylinder pressure sensor 35 during the reforming control execution calculating a certain combustion parameters (detected), and determines deterioration diagnosing the presence or absence of deterioration of the fuel reforming catalyst 28 by comparing the combustion parameter to a predetermined deterioration determination threshold. ここで、燃焼パラメータとしては、例えば、燃焼安定性指標COV(例えば図示平均有効圧力の変動率)、着火遅れ期間、主燃焼期間、燃焼重心、筒内圧力最大値等のうちの一つを算出する。 Here, the combustion parameter, for example, calculates the combustion stability index COV (e.g. rate of change in indicated mean effective pressure), the ignition delay period, the main combustion period, the combustion center of gravity, one of such cylinder pressure maximum value to.

図11に示すように、燃料改質触媒28が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒28による燃料の改質度合が低下して、エンジン11の燃焼状態が変化して燃焼パラメータが変化するため、改質制御の実行中に検出した燃焼パラメータを劣化判定閾値と比較すれば、燃料改質触媒28の劣化の有無を精度良く判定することができる。 As shown in FIG. 11, when the fuel reforming catalyst 28 is deteriorated, as compared to normal (when no degradation), reduced reforming the degree of fuel by the fuel reforming catalyst 28, the combustion state of the engine 11 is changed to change the combustion parameter and, comparing the combustion parameters detected during the reforming control execution deterioration determination threshold, the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

以下、本実施例2でECU34が実行する図12の触媒劣化診断ルーチンの処理内容を説明する。 Hereinafter, the processing contents of the catalyst deterioration diagnosis routine of FIG. 12 in the present embodiment 2 ECU 34 executes.

図12に示す触媒劣化診断ルーチンは、ECU34の電源オン期間中に所定周期で繰り返し実行される。 Catalyst deterioration diagnosis routine shown in FIG. 12 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 34. 本ルーチンが起動されると、まず、ステップ201で、改質運転モードであるか否かを判定し、改質運転モードであると判定された場合には、ステップ202に進み、EGR弁25を開弁した後、ステップ203に進み、改質用燃料噴射弁26で改質用の燃料を噴射して、燃料改質触媒28でEGRガス中の燃料を改質する改質制御を実行する。 When this routine is started, first, at step 201, it is determined whether the modified operating mode, when it is determined that the reforming operation mode, the program proceeds to step 202, the EGR valve 25 after opening, the flow proceeds to step 203, by injecting fuel for reforming the reforming fuel injection valve 26, the fuel reforming catalyst 28 executes modification control for reforming fuel in the EGR gas.

この後、ステップ204に進み、筒内圧力センサ35の出力に基づいて燃焼パラメータ(例えば、燃焼安定性指標COV、着火遅れ期間、主燃焼期間、燃焼重心、筒内圧力最大値等のうちの一つ)を算出する。 Then, the procedure proceeds to step 204, the combustion parameter based on the output of the cylinder pressure sensor 35 (e.g., combustion stability index COV, the ignition delay period, the main combustion period, the combustion center of gravity, one of such cylinder pressure maximum value One) is calculated. このステップ204の処理が特許請求の範囲でいう燃焼状態情報検出手段としての役割を果たす。 It serves as the combustion state information detecting means processing of step 204 which is defined in the appended claims.

この後、ステップ205に進み、改質用燃料の噴射量とEGRガス流量に応じた劣化判定閾値をマップ等により算出する。 Then, the procedure proceeds to step 205, is calculated by using a map or the like the degradation determination threshold value corresponding to the injection amount and the EGR gas flow rate of the fuel reforming. 更に、改質制御の開始前に検出した燃焼パラメータに応じて劣化判定閾値を補正するようにしても良い。 Furthermore, it is also possible to correct the deterioration determination threshold according to the combustion parameters detected before the start of the modification control.

この後、ステップ206に進み、燃焼パラメータを劣化判定閾値と比較して、燃焼パラメータが正常範囲内であるか否かを判定する。 Then, the procedure proceeds to step 206, by comparing the combustion parameter and the deterioration determination threshold, determines whether the combustion parameter is within the normal range. この際、燃焼パラメータとして、燃焼安定性指標COV、着火遅れ期間、主燃焼期間を用いる場合には、燃焼パラメータ(燃焼安定性指標COV、着火遅れ期間、主燃焼期間)が劣化判定閾値以下であるか否かによって、燃焼パラメータが正常範囲内であるか否かを判定する。 At this time, as the combustion parameter, in the case of using the combustion stability index COV, ignition delay period, the main combustion period, the combustion parameters (combustion stability index COV, the ignition delay period, the main combustion period) is equal to or less than the deterioration determination threshold depending on whether or not, determines whether the combustion parameter is within the normal range. 一方、燃焼パラメータとして、燃焼重心、筒内圧力最大値を用いる場合には、燃焼パラメータ(燃焼重心、筒内圧力最大値)が劣化判定閾値以上であるか否かによって、燃焼パラメータが正常範囲内であるか否かを判定する。 On the other hand, as the combustion parameter, in the case of using the centroid of combustion, cylinder pressure maximum value, the combustion parameter (centroid of combustion, cylinder pressure maximum value) depending on whether it is the deterioration determination threshold value or higher, the combustion parameters are within the normal range It determines whether or not it is.

このステップ206で、燃焼パラメータが正常範囲内であると判定された場合には、ステップ207に進み、燃料改質触媒28の劣化無し(正常)と判定して、本ルーチンを終了する。 In this step 206, when the combustion parameter is determined to be within the normal range, the process proceeds to step 207, it is determined without deterioration of the fuel reforming catalyst 28 (the normal), the routine ends.

これに対して、上記ステップ206で、燃焼パラメータが正常範囲内ではないと判定された場合には、ステップ208に進み、燃料改質触媒28の劣化有り(異常)と判定して、ステップ209に進み、フェールセーフ処理(EGRガス流量を減量すると共に改質用燃料の噴射を停止して燃料の改質を禁止する処理)を実行する。 In contrast, at step 206, when the combustion parameter is determined not to be within the normal range, the process proceeds to step 208, there deterioration of the fuel reforming catalyst 28 (abnormal) and determines, in step 209 proceeds to execute the fail-safe processing (processing to stop the injection of reforming fuel to prohibit modification of the fuel as well as reduced the EGR gas flow rate).

図13を用いて本実施例2の触媒劣化診断の実行例を説明する。 The execution of the catalyst deterioration diagnosis of the second embodiment will be described with reference to FIG. 13.
図13に示すように、通常運転モードから改質運転モードに切り換えられたときに、EGR弁25を開弁して排出ガスの一部をEGRガスとして吸気側へ還流させながら、改質用燃料噴射弁26でEGRガス中に改質用の燃料を噴射して、燃料改質触媒28でEGRガス中の燃料を燃焼性の高い状態に改質する改質制御を実行する。 As shown in FIG. 13, when switched from the normal operation mode to the reforming operation mode, under reflux to the intake side as EGR gas part of the exhaust gas by opening the EGR valve 25, the fuel reforming the EGR gas in the injection valve 26 to inject fuel for reforming, executes modifying control for reforming fuel in the EGR gas in the fuel reforming catalyst 28 in the high combustion state.

本実施例2では、この改質制御の実行中に筒内圧力センサ35の出力に基づいてエンジン11の燃焼状態の情報である燃焼パラメータを算出(検出)し、この燃焼パラメータを劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定する劣化診断を行うようにしたので、燃料改質触媒28の劣化の有無を精度良く判定することができる。 In the second embodiment, the reforming control during execution based on the output of the cylinder pressure sensor 35 calculates a combustion parameter which is information of a combustion state of the engine 11 (detected), and the combustion parameter deterioration determination threshold since to perform the determining deterioration diagnosing the presence or absence of deterioration of the fuel reforming catalysts 28 in comparison, the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

また、図13に破線で示すように、燃料改質触媒28の劣化診断機能を備えていないシステムでは、燃料改質触媒28の劣化が発生しても、それを検出できず、燃料改質触媒28の劣化発生時にフェールセーフ処理を実施できないため、エンジン11の燃焼状態が悪化してトルク変動が発生してドライバビリティが悪化する可能性がある。 Further, as indicated by a broken line in FIG. 13, in a system without a deterioration diagnosis function of the fuel reforming catalyst 28, deterioration of the fuel reforming catalyst 28 occurs, it can not detect it, the fuel reforming catalyst since 28 when degradation occurs that can not be carried out fail-safe processing, drivability combustion state and the torque variation is generated by deterioration of the engine 11 is likely to deteriorate.

これに対して、本実施例2では、改質制御の実行中に検出した燃焼パラメータを劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定し、燃料改質触媒28の劣化有りと判定された場合には、フェールセーフ処理(EGRガス流量を減量すると共に改質用燃料の噴射を停止して燃料の改質を禁止する処理)を実行するようにしたので、エンジン11の燃焼状態の悪化を抑制してトルク変動の発生を抑制することができ、ドライバビリティの悪化を防止することができる。 In contrast, in Example 2, by comparing the combustion parameters detected during the reforming control execution deterioration determination threshold to determine the presence or absence of deterioration of the fuel reforming catalyst 28, the deterioration of the fuel reforming catalysts 28 when it is determined that there is, since the to execute the fail-safe processing (processing to stop the injection of reforming fuel to prohibit modification of the fuel as well as reduced the EGR gas flow rate), the engine 11 by suppressing the deterioration of the combustion state it is possible to suppress the occurrence of torque fluctuation, it is possible to prevent deterioration in drivability.

尚、上記実施例2では、改質制御の実行中に検出した燃焼パラメータを劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしたが、劣化診断方法は、これに限定されず、適宜変更しても良く、例えば、改質制御の開始前に検出した燃焼パラメータと改質制御の開始後に検出した燃焼パラメータとの差又は比を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしても良い。 In the above embodiment 2 has been possible to determine the presence or absence of deterioration of the fuel reforming catalyst 28 combustion parameters detected during the reforming control execution compared to the deterioration determination threshold value, the degradation diagnostic method, which It is not limited to, may be suitably changed, for example, Samata the combustion parameters detected after the start of the combustion parameter and the reforming control detected before the start of the modification control compares the ratio with the degradation determination threshold fuel may be determined whether the deterioration of the reforming catalyst 28.

燃料改質触媒28が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒28による燃料の改質度合が低下して、改質制御の開始前の燃焼状態と改質制御の開始後の燃焼状態との関係が正常時とは異なってくるため、改質制御の開始前に検出した燃焼パラメータと改質制御の開始後に検出した燃焼パラメータとを用いれば、燃料改質触媒28の劣化の有無を精度良く判定することができる。 When deterioration of the fuel reforming catalyst 28, as compared to normal (when no degradation), reduced reforming the degree of fuel by the fuel reforming catalyst 28, the reforming control before starting the combustion state and the reforming control since the relationship between the combustion state after the start becomes different from that during normal, using a combustion parameter detected after the start of combustion parameters and the reforming control detected before the start of the reforming control, the fuel reforming catalyst 28 the presence or absence of degradation can be determined accurately.

また、上記実施例2では、燃焼パラメータ(燃焼状態の情報)として、燃焼安定性指標COV、着火遅れ期間、主燃焼期間、燃焼重心、筒内圧力最大値等を検出するようにしたが、これに限定されず、燃焼パラメータ(燃焼状態の情報)として、例えば、EGR限界、燃焼速度、エンジン回転変動、トルク変動等を検出するようにしても良い。 Further, in the second embodiment, as a combustion parameter (information of the combustion state), the combustion stability index COV, the ignition delay period, the main combustion period, the combustion center of gravity, but to detect the in-cylinder pressure maximum value and the like, which not limited to, as a combustion parameter (information of the combustion state), for example, EGR limit, burn rate, engine speed fluctuation may be detected torque fluctuations.

また、上記実施例2では、燃焼状態を検出するセンサとして、筒内圧力センサ35を用いるようにしたが、これに限定されず、例えば、点火プラグ18に流れるイオン電流を検出するセンサを点火プラグ18と一体又は別体で設けるようにしても良い。 Further, in the second embodiment, as a sensor for detecting the combustion state has been to use a cylinder pressure sensor 35 is not limited to this, for example, ignition sensor for detecting an ion current flowing through the spark plug 18 plug 18 and may be provided integrally with or separately.

次に、図14乃至図17を用いて本発明の実施例3を説明する。 Next, a third embodiment of the present invention will be described with reference to FIGS. 14 to 17. 但し、前記実施例1,2と実質的に同一部分については説明を省略又は簡略化し、主として前記実施例1,2と異なる部分について説明する。 However, the for the substantially same parts as in Examples 1 and 2 are omitted or simplified description, a portion mainly different from the first and second embodiments.

本実施例3では、図14に示すように、EGR配管24のうちの燃料改質触媒28の出口側に、燃料の改質度合を検出する改質度合センサ36(改質度合検出手段)が設けられている。 In the third embodiment, as shown in FIG. 14, the outlet side of the fuel reforming catalysts 28 of the EGR pipe 24, the reformed degree sensor 36 for detecting the modification degree of the fuel (reforming degree detecting means) It is provided. この改質度合センサ36は、例えば、燃料の改質度合として水素濃度を検出する水素センサを用いる。 The modification degree sensor 36, for example, using a hydrogen sensor that detects the hydrogen concentration as a modifying degree of the fuel. 尚、温度センサ30,31を省略した構成としても良い。 It may be configured to omit the temperature sensor 30, 31.

また、本実施例3では、ECU34により後述する図16の触媒劣化診断ルーチンを実行することで、改質制御の実行中に改質度合センサ36で検出した燃料の改質度合(例えば水素濃度)を所定の劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定する劣化診断を行う。 Further, according to the third embodiment, by executing the catalyst deterioration diagnosis routine of FIG. 16 to be described later by ECU 34, modification degree of the fuel detected during the reforming control performed in the reforming degree sensor 36 (e.g., the hydrogen concentration) is compared with a predetermined deterioration determination threshold performs determining deterioration diagnosing the presence or absence of deterioration of the fuel reforming catalyst 28.

図15に示すように、燃料改質触媒28が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒28による燃料の改質度合が低下するため、改質制御の実行中に検出した改質度合を劣化判定閾値と比較すれば、燃料改質触媒28の劣化の有無を精度良く判定することができる。 As shown in FIG. 15, when the deterioration fuel reforming catalyst 28, as compared to normal (when no degradation), the modification degree of the fuel by the fuel reforming catalyst 28 is lowered, while the reforming control execution by comparing the detected modification degree and the deterioration determination threshold, the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

以下、本実施例3でECU34が実行する図16の触媒劣化診断ルーチンの処理内容を説明する。 Hereinafter, the processing contents of the catalyst deterioration diagnosis routine of FIG. 16 in the present embodiment 3 ECU 34 executes.

図16に示す触媒劣化診断ルーチンは、ECU34の電源オン期間中に所定周期で繰り返し実行される。 Catalyst deterioration diagnosis routine shown in FIG. 16 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 34. 本ルーチンが起動されると、まず、ステップ301で、改質運転モードであるか否かを判定し、改質運転モードであると判定された場合には、ステップ302に進み、EGR弁25を開弁した後、ステップ303に進み、改質用燃料噴射弁26で改質用の燃料を噴射して、燃料改質触媒28でEGRガス中の燃料を改質する改質制御を実行する。 When this routine is started, first, at step 301, it is determined whether the modified operating mode, when it is determined that the reforming operation mode, the program proceeds to step 302, the EGR valve 25 after opening, the flow proceeds to step 303, by injecting fuel for reforming the reforming fuel injection valve 26, the fuel reforming catalyst 28 executes modification control for reforming fuel in the EGR gas.

この後、ステップ304に進み、改質度合センサ36で検出した燃料の改質度合(例えば水素濃度)を読み込んだ後、ステップ305に進み、改質用燃料の噴射量とEGRガス流量に応じた劣化判定閾値をマップ等により算出する。 Then, the procedure proceeds to step 304, after reading the reformed degree of fuel detected by the reforming degree sensor 36 (e.g., hydrogen concentration), the process proceeds to step 305, in accordance with the injection amount and the EGR gas flow rate of the fuel reforming It is calculated by a map or the like the deterioration determination threshold. 更に、改質制御の開始前に検出した改質度合に応じて劣化判定閾値を補正するようにしても良い。 Furthermore, it is also possible to correct the deterioration determination threshold according to modification degree detected before the start of the modification control.

この後、ステップ306に進み、改質度合が劣化判定閾値以上であるか否かを判定する。 Then, the procedure proceeds to step 306, determines whether the modification degree is deterioration determination threshold value or higher. このステップ306で、改質度合が劣化判定閾値以上であると判定された場合には、ステップ307に進み、燃料改質触媒28の劣化無し(正常)と判定して、本ルーチンを終了する。 In this step 306, if the modification degree is determined to be deterioration determination threshold value or more, the process proceeds to step 307, it is determined without deterioration of the fuel reforming catalyst 28 (the normal), the routine ends.

これに対して、上記ステップ306で、改質度合が劣化判定閾値よりも小さいと判定された場合には、ステップ308に進み、燃料改質触媒28の劣化有り(異常)と判定して、ステップ309に進み、フェールセーフ処理(EGRガス流量を減量すると共に改質用燃料の噴射を停止して燃料の改質を禁止する処理)を実行する。 In contrast, at step 306, if the modification degree is determined to be smaller than the deterioration determination threshold value, the process proceeds to step 308, deterioration of the fuel reforming catalyst 28 there (abnormal) and to determine, step proceeds to 309, executes the fail-safe processing (processing to stop the injection of reforming fuel to prohibit modification of the fuel as well as reduced the EGR gas flow rate).

図17を用いて本実施例3の触媒劣化診断の実行例を説明する。 The execution of the catalyst deterioration diagnosis of the third embodiment will be described with reference to FIG. 17.
図17に示すように、通常運転モードから改質運転モードに切り換えられたときに、EGR弁25を開弁して排出ガスの一部をEGRガスとして吸気側へ還流させながら、改質用燃料噴射弁26でEGRガス中に改質用の燃料を噴射して、燃料改質触媒28でEGRガス中の燃料を燃焼性の高い状態に改質する改質制御を実行する。 As shown in FIG. 17, when switched from the normal operation mode to the reforming operation mode, under reflux to the intake side as EGR gas part of the exhaust gas by opening the EGR valve 25, the fuel reforming the EGR gas in the injection valve 26 to inject fuel for reforming, executes modifying control for reforming fuel in the EGR gas in the fuel reforming catalyst 28 in the high combustion state.

本実施例3では、この改質制御の実行中に改質度合センサ36で燃料の改質度合(例えば水素濃度)検出し、この改質度合を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定する劣化診断を行うようにしたので、燃料改質触媒28の劣化の有無を精度良く判定することができる。 In Example 3, the reformer reforming the degree of fuel running in the reforming degree sensor 36 of the control (for example, a hydrogen concentration) is detected, the fuel reforming catalyst 28 by comparing the modification degree and the deterioration determination threshold since the presence or absence of degradation were to perform the deterioration diagnosis determining the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

また、図17に破線で示すように、燃料改質触媒28の劣化診断機能を備えていないシステムでは、燃料改質触媒28の劣化が発生しても、それを検出できず、燃料改質触媒28の劣化発生時にフェールセーフ処理を実施できないため、エンジン11の燃焼状態が悪化してトルク変動が発生してドライバビリティが悪化する可能性がある。 Further, as shown by the broken line in FIG. 17, in a system without a deterioration diagnosis function of the fuel reforming catalyst 28, deterioration of the fuel reforming catalyst 28 occurs, it can not detect it, the fuel reforming catalyst since 28 when degradation occurs that can not be carried out fail-safe processing, drivability combustion state and the torque variation is generated by deterioration of the engine 11 is likely to deteriorate.

これに対して、本実施例3では、改質制御の実行中に検出した改質度合を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定し、燃料改質触媒28の劣化有りと判定された場合には、フェールセーフ処理(EGRガス流量を減量すると共に改質用燃料の噴射を停止して燃料の改質を禁止する処理)を実行するようにしたので、エンジン11の燃焼状態の悪化を抑制してトルク変動の発生を抑制することができ、ドライバビリティの悪化を防止することができる。 In contrast, in Example 3, the modification degree detected during the reforming control execution as compared with the deterioration determination threshold to determine the presence or absence of deterioration of the fuel reforming catalyst 28, the fuel reforming catalysts 28 If it is determined that there is deterioration, since so as to perform a fail-safe processing (processing to stop the injection of reforming fuel to prohibit modification of the fuel as well as reduced the EGR gas flow rate), the engine 11 and of suppressing the deterioration of the combustion state it is possible to suppress the occurrence of torque fluctuation, it is possible to prevent deterioration in drivability.

尚、上記実施例3では、改質制御の実行中に検出した改質度合を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしたが、劣化診断方法は、これに限定されず、適宜変更しても良く、例えば、改質制御の開始前に検出した改質度合と改質制御の開始後に検出した改質度合との差又は比を劣化判定閾値と比較して燃料改質触媒28の劣化の有無を判定するようにしても良い。 In the above embodiment 3, it has been to determine the presence or absence of deterioration of the fuel reforming catalyst 28 a modification degree detected during the reforming control execution compared to the deterioration determination threshold value, the degradation diagnostic method, is not limited to this, comparison may be suitably changed, for example, Samata the reforming degree detected after the start of reforming degree and a reforming control detected before the start of the modification control the ratio between the deterioration determination threshold it may be determined whether the deterioration of the fuel reforming catalyst 28 in.

燃料改質触媒28が劣化すると、正常時(劣化無し時)と比べて、燃料改質触媒28による燃料の改質度合が低下して、改質制御の開始前の燃料の改質度合と改質制御の開始後の燃料の改質度合との関係が正常時とは異なってくるため、改質制御の開始前に検出した改質度合と改質制御の開始後に検出した改質度合とを用いれば、燃料改質触媒28の劣化の有無を精度良く判定することができる。 When deterioration of the fuel reforming catalyst 28, as compared to normal (when no degradation), reduced reforming the degree of fuel by the fuel reforming catalyst 28, the reforming degree and reforming the fuel before the start of the modification control because the relationship between reforming the degree of fuel after the start of the quality control comes different from the normal, and the modification degree that was detected after the start of the modification degree and the reforming control has been detected prior to the start of the reforming control by using the presence or absence of deterioration of the fuel reforming catalysts 28 can be accurately determined.

また、上記各実施例1〜3では、EGR配管に改質用燃料噴射弁と燃料改質触媒を配置したシステムに本発明を適用したが、これに限定されず、例えば、吸気管に吸入空気を過給する過給機を設けると共に、吸気管のうちの過給機の下流側に改質用燃料噴射弁と燃料改質触媒を配置したシステムに本発明を適用しても良い。 Further, the in the first to third embodiments, the present invention is applied to the system of arranging the fuel injection valve and the fuel reforming catalyst for reforming the EGR pipe is not limited to this, for example, the intake air in the intake pipe the provided with a supercharger for supercharging, the present invention may be applied to a system of arranging the fuel injection valve and the fuel reforming catalyst for reforming the downstream side of the turbocharger of the intake pipe.

その他、本発明は、吸気ポート噴射式エンジンに限定されず、筒内噴射式エンジンや、吸気ポート噴射用の燃料噴射弁と筒内噴射用の燃料噴射弁の両方を備えたデュアル噴射式のエンジンにも適用して実施できる。 In addition, the present invention is not limited to the intake port injection engine, and a direct injection type engine, a dual injection type engine having both of the fuel injection valve and a fuel injection valve for cylinder injection for the intake port injection to be carried out also applied.

11…エンジン(内燃機関)、12…吸気管、14…スロットルバルブ、17…燃料噴射弁、18…点火プラグ、19…排気管、23…EGR装置、24…EGR配管、25…EGR弁、26…改質用燃料噴射弁(改質用燃料噴射手段)、27…燃料噴射装置、28…燃料改質触媒、29…燃料改質器、30…入口側温度センサ(入口側温度検出手段)、31…出口側温度センサ(出口側温度検出手段)、34…ECU(触媒劣化診断手段,燃焼状態情報検出手段)、35…筒内圧力センサ、36…改質度合センサ(改質度合検出手段) 11 ... engine (internal combustion engine), 12 ... intake pipe, 14 ... throttle valve, 17: fuel injector, 18 ... ignition plug, 19 ... exhaust pipe, 23 ... EGR device, 24 ... EGR pipe, 25 ... EGR valve, 26 ... reforming fuel injection valve (reforming fuel injection means), 27 ... fuel injection system, 28: fuel reforming catalyst, 29 ... fuel reformer, 30 ... inlet side temperature sensor (inlet side temperature detection means), 31 ... outlet temperature sensor (outlet temperature detecting means), 34 ... ECU (catalyst deterioration diagnosis means, the combustion state information detecting means), 35 ... cylinder pressure sensor, 36 ... reforming degree sensor (modification degree detecting means)

Claims (9)

  1. 内燃機関の吸気系に供給される媒体ガス中に改質用の燃料を噴射する改質用燃料噴射手段と、前記媒体ガス中の燃料を改質する燃料改質触媒とを備えた内燃機関の燃料改質システムの触媒劣化診断装置において、 A fuel injection means for modifying that injects fuel for reforming the medium gas supplied to the intake system of an internal combustion engine, the internal combustion engine having a fuel reforming catalyst for reforming fuel in the medium gas in the catalyst deterioration diagnosis device for a fuel reforming system,
    前記燃料改質触媒での反応熱量の情報を検出する反応熱量情報検出手段と、 And reaction heat information detecting means for detecting information of a reaction heat at the fuel reforming catalyst,
    前記反応熱量情報検出手段で検出した反応熱量の情報に基づいて前記燃料改質触媒の劣化診断を行う触媒劣化診断手段と を備えていることを特徴とする内燃機関の燃料改質システムの触媒劣化診断装置。 Catalyst deterioration of the internal combustion engine of the fuel reformer system characterized by comprising a catalyst deterioration diagnosis means for performing deterioration diagnosis of the fuel reforming catalyst on the basis of the reaction heat Info reaction heat detected by the detection means diagnostic equipment.
  2. 前記反応熱量情報検出手段として、前記燃料改質触媒の入口側の温度(以下「触媒入口側温度」という)を検出する入口側温度検出手段と、前記燃料改質触媒の出口側の温度(以下「触媒出口側温度」という)を検出する出口側温度検出手段とを備え、 As the reaction heat information detecting means, an inlet-side temperature detection means for detecting the fuel reforming inlet side of the temperature of the catalyst (hereinafter referred to as "catalyst inlet side temperature"), the fuel reforming catalyst of the outlet temperature (hereinafter an outlet-side temperature detection means for detecting a) "catalytic outlet temperature",
    前記触媒劣化診断手段は、前記燃料改質触媒で燃料を改質する改質制御の実行中に前記入口側温度検出手段で検出した触媒入口側温度と前記出口側温度検出手段で検出した触媒出口側温度とに基づいて前記燃料改質触媒の劣化診断を行うことを特徴とする請求項1に記載の内燃機関の燃料改質システムの触媒劣化診断装置。 The catalyst deterioration diagnosis means, catalyst outlet detected by the detected the catalyst inlet-side temperature by the inlet-side temperature detection means fuel during reforming control for reforming in the fuel reforming catalyst wherein the outlet-side temperature detection means catalyst deterioration diagnosis apparatus for an internal combustion engine fuel reforming system according to claim 1, characterized in that the deterioration diagnosis of the fuel reforming catalyst on the basis of the side temperature.
  3. 前記反応熱量情報検出手段として、前記燃料改質触媒の温度(以下「触媒温度」という)又は前記燃料改質触媒の出口側の温度(以下「触媒出口側温度」という)を検出する温度検出手段を備え、 As the reaction heat information detecting means, the fuel reforming temperature detection means for detecting a temperature (hereinafter "catalyst temperature" hereinafter) or the outlet side of the fuel reforming catalyst temperature (hereinafter referred to as "catalyst outlet temperature") of the catalyst equipped with a,
    前記触媒劣化診断手段は、前記燃料改質触媒で燃料を改質する改質制御の開始前に前記温度検出手段で検出した触媒温度又は触媒出口側温度と前記改質制御の開始後に前記温度検出手段で検出した触媒温度又は触媒出口側温度とに基づいて前記燃料改質触媒の劣化診断を行うことを特徴とする請求項1に記載の内燃機関の燃料改質システムの触媒劣化診断装置。 The catalyst deterioration diagnosis means, the temperature detected after the start of the modification control the catalyst temperature or catalyst outlet temperature detected by said temperature detecting means before the start of the reforming control for reforming fuel in the fuel reforming catalyst catalyst deterioration diagnosis apparatus for an internal combustion engine fuel reforming system according to claim 1, characterized in that the deterioration diagnosis of the fuel reforming catalyst on the basis of the catalyst temperature or catalyst outlet temperature detected by the means.
  4. 内燃機関の吸気系に供給される媒体ガス中に改質用の燃料を噴射する改質用燃料噴射手段と、前記媒体ガス中の燃料を改質する燃料改質触媒とを備えた内燃機関の燃料改質システムの触媒劣化診断装置において、 A fuel injection means for modifying that injects fuel for reforming the medium gas supplied to the intake system of an internal combustion engine, the internal combustion engine having a fuel reforming catalyst for reforming fuel in the medium gas in the catalyst deterioration diagnosis device for a fuel reforming system,
    前記内燃機関の燃焼状態の情報を検出する燃焼状態情報検出手段と、 And combustion state information detecting means for detecting information on the combustion state of the internal combustion engine,
    前記燃焼状態情報検出手段で検出した燃焼状態の情報に基づいて前記燃料改質触媒の劣化診断を行う触媒劣化診断手段と を備えていることを特徴とする内燃機関の燃料改質システムの触媒劣化診断装置。 Catalyst deterioration of the combustion state information on the basis of the detected information of the combustion state detecting means for an internal combustion engine, characterized by comprising a catalyst deterioration diagnosis means for performing deterioration diagnosis of the fuel reforming catalyst fuel reforming system diagnostic equipment.
  5. 前記触媒劣化診断手段は、前記燃料改質触媒で燃料を改質する改質制御の開始前に前記燃焼状態情報検出手段で検出した燃焼状態の情報と前記改質制御の開始後に前記燃焼状態情報検出手段で検出した燃焼状態の情報とに基づいて前記燃料改質触媒の劣化診断を行うことを特徴とする請求項4に記載の内燃機関の燃料改質システムの触媒劣化診断装置。 The catalyst deterioration diagnosis means, the combustion state information after the start of the fuel reforming catalyst wherein the information and the modification control of the combustion state detected by the combustion state information detecting means before the start of the reforming control for reforming fuel in catalyst deterioration diagnosis apparatus for an internal combustion engine fuel reforming system according to claim 4, characterized in that the deterioration diagnosis of the fuel reforming catalyst on the basis of the combustion state detected by the detection means information.
  6. 前記燃焼状態情報検出手段は、前記燃焼状態の情報として、燃焼安定性指標、着火遅れ期間、主燃焼期間、燃焼重心、筒内圧力最大値、EGR限界、燃焼速度のうちの少なくとも一つを検出することを特徴とする請求項4又は5に記載の内燃機関の燃料改質システムの触媒劣化診断装置。 The combustion state information detecting means, as the information of the combustion state, the combustion stability index, the ignition delay period, the main combustion period, the combustion center of gravity, cylinder pressure maximum value, EGR limit, detecting at least one of a burning rate catalyst deterioration diagnosis apparatus for an internal combustion engine fuel reforming system according to claim 4 or 5, characterized in that.
  7. 内燃機関の吸気系に供給される媒体ガス中に改質用の燃料を噴射する改質用燃料噴射手段と、前記媒体ガス中の燃料を改質する燃料改質触媒とを備えた内燃機関の燃料改質システムの触媒劣化診断装置において、 A fuel injection means for modifying that injects fuel for reforming the medium gas supplied to the intake system of an internal combustion engine, the internal combustion engine having a fuel reforming catalyst for reforming fuel in the medium gas in the catalyst deterioration diagnosis device for a fuel reforming system,
    前記燃料改質触媒の出口側で燃料の改質度合を検出する改質度合検出手段と、 A reforming degree detecting means for detecting the modification degree of the fuel at the outlet side of the fuel reforming catalyst,
    前記改質度合検出手段で検出した燃料の改質度合に基づいて前記燃料改質触媒の劣化診断を行う触媒劣化診断手段と を備えていることを特徴とする内燃機関の燃料改質システムの触媒劣化診断装置。 The catalyst of the reforming degree based on the modification degree of the detected fuel by the detection means of the internal combustion engine, characterized by comprising a catalyst deterioration diagnosis means for performing deterioration diagnosis of the fuel reforming catalyst fuel reforming system deterioration diagnostic device.
  8. 前記触媒劣化診断手段は、前記燃料改質触媒で燃料を改質する改質制御の開始前に前記改質度合検出手段で検出した燃料の改質度合と前記改質制御の開始後に前記改質度合検出手段で検出した燃料の改質度合とに基づいて前記燃料改質触媒の劣化診断を行うことを特徴とする請求項7に記載の内燃機関の燃料改質システムの触媒劣化診断装置。 The catalyst deterioration diagnosis means, the reforming after starting the reforming degree and the reforming control of the fuel detected by the reforming degree detecting means before the start of the reforming control for reforming fuel in the fuel reforming catalyst catalyst deterioration diagnosis apparatus for an internal combustion engine fuel reforming system according to claim 7, characterized in that the deterioration diagnosis of the fuel reforming catalyst on the basis of the modification degree of the fuel detected by the degree detecting means.
  9. 前記改質度合検出手段は、前記燃料の改質度合として水素濃度を検出する水素センサであることを特徴とする請求項7又は8に記載の内燃機関の燃料改質システムの触媒劣化診断装置。 The reforming degree detecting means, the catalyst deterioration diagnosis apparatus for an internal combustion engine of the fuel reforming system according to claim 7 or 8, characterized in that a hydrogen sensor that detects the hydrogen concentration as a modifying degree of the fuel.
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Free format text: JAPANESE INTERMEDIATE CODE: A300

Effective date: 20140805