• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a method for detecting a leak in a heat recovery system (5) of an internal combustion engine (1) of a motor vehicle, wherein the heat recovery system (5) comprises at least one combustible working medium, a working medium circuit (6) with at least one EGR evaporator (7), a pump (8) and at least one expansion machine (9). To be able to detect leaks in the EGR evaporator (7) of a heat recovery system (5) in the simplest possible way early and reliably, it is provided that the internal combustion engine (1) is operated in overrun mode, that the oxygen concentration in the exhaust gas is determined and with a defined lower limit Threshold is compared and that falls below the lower threshold, a leak on the EGR evaporator (7) is detected.
    公开号:AT516615A4
    申请号:T50744/2015
    申请日:2015-08-28
    公开日:2016-07-15
    发明作者:Klemens Dipl Ing Neunteufl；Gerald Dipl Ing Gradwohl；Helmut Dipl Ing Altendorfer；Fabio Cococcetta；Thomas Eckhardt
    申请人:Avl List Gmbh；
    IPC主号:
    专利说明:

    The invention relates to a method for detecting a leak in a heat recovery system of an internal combustion engine of a motor vehicle, wherein the heat recovery system comprises at least one combustible working fluid, a working fluid circuit with at least one EGR evaporator, a pump and at least one expansion machine.
    When operating a system for heat recovery with a combustible working medium in conjunction with an internal combustion engine and an exhaust gas recirculation (EGR) evaporator (EGR = Exhaust Gas Recirculation) is the detection of leaks in the system of high priority. Leakage in a heat recovery system can lead, among other things, to the following critical scenarios: • Excess of the working fluid into the environment - creates a fire hazard when using a combustible working fluid such as ethanol. • Entry of combustible working fluid into the internal combustion engine - causes damage if, for example, the working fluid enters the combustion chamber via an EGR evaporator. • Overheating of system components due to insufficient working fluid level - can, for example, lead to overheating of the exhaust gas evaporator if the mass flow of the working medium is too low.
    To detect leakage in a heat recovery system, for example, the following methods are known: • Monitoring the level of the working fluid in the expansion tank by means of a level sensor. If the level is too low, a leak is detected. • Leak test by pressurizing the deactivated cold system and then observing the pressure gradient. Too rapid pressure drop indicates a leak. • Measure the electrical conductivity of the insulation of the heat recovery system. A change in conductivity is a sign of leaks.
    US 6,526,358 Bl describes a method for detecting leaks and blockages in a fluid circuit, wherein pressure, temperature and flow rate at different points of the circuit are measured and correlated.
    JP 2010-156314 A discloses a heat recovery system for an internal combustion engine wherein for leakage detection 02 sensors are arranged in the coolant circuit of the heat recovery system.
    Known methods have the disadvantage that they can either be performed only in the deactivated state and / or that devices such as additional sensors or the like are required.
    The object of the invention is to be able to detect early and reliably leakages in the EGR evaporator of a heat recovery system based on existing sensors and the simplest possible way.
    According to the invention, this takes place in that the internal combustion engine is operated in overrun mode, that the oxygen concentration in the exhaust gas is determined and compared with a defined lower threshold value and that a leak on the EGR evaporator is detected when the lower threshold value is undershot.
    It is preferably provided that the detection of a leak on the EGR evaporator is only active when the internal combustion engine is in coasting operation.
    A particularly low effort in detecting a leak in the EGR evaporator is necessary when the oxygen concentration in the exhaust gas of the internal combustion engine by means of a sensor, preferably a λ-sensor or a NOx sensor, is determined. λ sensors and / or NOx sensors are used by default for the control of the internal combustion engine to meet emissions regulations. These existing λ sensors and / or NOx sensors can thus also be used in accordance with the teachings of the present invention to detect leaks in the EGR evaporator.
    The measurement of the oxygen concentration is desirably performed upstream of an exhaust aftertreatment system to avoid falsification of the measurement result.
    In particular, when a combustible working fluid is used in the heat recovery system, leaks can be detected on the EGR evaporator with little effort in this way.
    The prerequisite for the error-free detection of leaks by determining the oxygen concentration is that the internal combustion engine is in a defined operating state. In particular, the following conditions must be met: • overrun operation of the internal combustion engine, • sensor for measuring the oxygen concentration is active, • no fuel injection, e.g. to increase the exhaust gas temperature, • No error in the fuel injection system.
    If leak detection is activated, the oxygen concentration is compared with a lower threshold value for a defined period of time. If the oxygen concentration is below this threshold value, then it can be assumed that combustible working medium reaches the combustion chambers of the internal combustion engine via a leakage at the EGR evaporator and the oxygen concentration in the exhaust gas is reduced there by thermal conversion (combustion). This reduction of the oxygen concentration in the exhaust gas is measured via a sensor that is already necessary for the operation of the internal combustion engine. If the measured oxygen concentration is below a defined threshold value for more than a specific time, a leakage at the EGR evaporator is detected. In the case of large leaks in the EGR evaporator, the oxygen concentration can also reach zero in extreme cases.
    The heat recovery system can be operated as a closed or open circuit.
    The inventive method has the advantage, in comparison to the prior art, that no further sensors or devices are necessary.
    The FIGURE schematically shows an internal combustion engine 1 with an intake manifold 2 and an exhaust manifold 3, and an exhaust gas recirculation line 4 between the intake manifold 2 and the exhaust manifold 3. For recovering the exhaust heat is a heat recovery system 5 with a working medium circuit 6 for a working fluid, with at least one EGR Evaporator 7, a pump 8 and at least one expansion machine 9 is provided. 10 denotes a capacitor. 12 denotes the control unit of the internal combustion engine. Any filters, catalysts, control elements and heat exchangers in the inlet section 2 and outlet section 3 are not shown. Via injectors 11 fuel is injected into the combustion chambers of the internal combustion engine 1.
    In Auslassstrang 3, a sensor 13, for example, a λ-sensor or a NOx sensor is arranged, which is already installed as standard for regulating the emissions in today's conventional motor vehicles. When the leaks are detected, the oxygen concentration measured in the outlet leg 3 via the sensor 13 is compared with a predefined lower threshold value for a defined period of time.
    If the oxygen concentration measured via the sensor 13 is below this threshold value, then it can be assumed that combustible working medium reaches the combustion chambers of the internal combustion engine via a leakage at the EGR evaporator and the oxygen concentration in the exhaust gas is reduced there by thermal conversion (combustion). If the measured oxygen concentration is below the defined threshold value for longer than a predefined minimum time, a leakage at the EGR evaporator is detected. In the case of large leaks in the EGR evaporator, the oxygen concentration can also reach zero in extreme cases.
    Leak detection is activated when the following conditions are met: • Internal combustion engine 1 is in coasting mode, • Sensor 13 is active, • There is no fuel injection, for example to raise the exhaust gas temperature, and • There is no fault in the fuel injection system ,
    With the method described, it is possible to detect leaks in the EGR evaporator 7 of the heat recovery system 5 with extremely little effort and without additional components or sensors.
    权利要求:
    Claims (8)
    [1]
    1. A method for detecting a leak in a heat recovery system (5) of an internal combustion engine (1) of a motor vehicle, wherein the heat recovery system (5) at least one combustible working fluid, a working medium circuit (6) with at least one EGR evaporator (7), a pump (8) and at least one expansion machine (9), characterized in that the internal combustion engine (1) is operated in overrun mode, that the oxygen concentration in the exhaust gas is determined and compared with a defined lower threshold value and that falls below the lower threshold value, a leak on EGR evaporator (7) is detected.
    [2]
    2. The method according to claim 1, characterized in that the detection of a leak in the EGR evaporator (7) is only active when the internal combustion engine (1) is in overrun mode.
    [3]
    3. The method according to claim 1 or 2, characterized in that the oxygen concentration in the exhaust gas of the internal combustion engine (1) by means of at least one - preferably arranged upstream of an exhaust aftertreatment system - sensor (13) - is determined.
    [4]
    4. The method according to claim 3, characterized in that the sensor (13) is a λ-sensor or a NOx sensor.
    [5]
    5. The method according to claim 3 or 4, characterized in that the detection of a leak on the EGR evaporator (7) is only active when the sensor is active.
    [6]
    6. The method according to any one of claims 1 to 5, characterized in that the detection of a leak in the EGR evaporator (7) is only active when the fuel injection is switched off.
    [7]
    7. The method according to any one of claims 1 to 6, characterized in that the detection of a leak in the EGR evaporator (7) is deactivated when there is a fault in the fuel injection system.
    [8]
    8. The method according to any one of claims 1 to 7, characterized in that the leakage at the EGR evaporator (7) is detected when the undershooting of the lower threshold takes place over a defined minimum period of time. 2015 08 28 Fu
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP2133544A1|2007-04-06|2009-12-16|Sanden Corporation|Waste heat-using device for internal combustion engine|
    WO2012100212A1|2011-01-20|2012-07-26|Cummins Intellectual Property, Inc.|Rankine cycle waste heat recovery system and method with improved egr temperature control|
    DE102013216543A1|2012-08-29|2014-03-06|GM Global Technology Operations LLC |SYSTEM AND METHOD FOR CONTROLLING A FLUID FLOW IN AND / OR FROM A CATALYTIC HEAT EXCHANGER BASED ON A CATALYST TEMPERATURE|
    DE102012221153A1|2012-11-20|2014-06-05|Robert Bosch Gmbh|Method for monitoring system for recovering energy from waste heat stream of self-activating combustion engine, involves arranging fluid circuit in current flow path, measuring and validating property of fluid circuit during operation|
    US6526358B1|1999-10-01|2003-02-25|General Electric Company|Model-based detection of leaks and blockages in fluid handling systems|
    US6568246B1|2002-01-11|2003-05-27|Ford Global Technologies, L.L.C.|System and method for detecting an air leak in an exhaust system coupled to an engine|
    US6752128B2|2002-06-12|2004-06-22|Denso Corporation|Intake system failure detecting device and method for engines|
    US8850814B2|2009-06-11|2014-10-07|Ormat Technologies, Inc.|Waste heat recovery system|
    JP2010156314A|2009-01-05|2010-07-15|Toyota Motor Corp|Waste heat recovery device and engine|
    US9140627B2|2013-10-29|2015-09-22|Ford Global Technologies, Llc|Cooling fan assisted engine-off natural vacuum test|
    JP6410851B2|2014-06-26|2018-10-24|ボルボトラックコーポレーション|Waste heat recovery device|
    DE102014225059B4|2014-12-05|2022-01-27|Robert Bosch Gmbh|Method for operating a waste heat utilization arrangement|
    US10294891B2|2015-11-12|2019-05-21|Innovation Management And Sustainable Technologies S.A. De C.V.|Energy collector system applicable to combustion engines|
    AT518522B1|2016-07-18|2017-11-15|Avl List Gmbh|METHOD FOR DETECTING A LEAKAGE IN A HEAT RECOVERY SYSTEM|
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    US10330033B2|2016-12-01|2019-06-25|Ford Global Technologies, Llc|Method and system for exhaust heat recovery|AT518522B1|2016-07-18|2017-11-15|Avl List Gmbh|METHOD FOR DETECTING A LEAKAGE IN A HEAT RECOVERY SYSTEM|
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    法律状态:
    2017-04-15| HC| Change of the firm name or firm address|Owner name: AVL LIST GMBH, AT Effective date: 20170222 Owner name: FPT INDUSTRIAL, IT Effective date: 20170222 Owner name: IVECO SPA, IT Effective date: 20170222 |
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50744/2015A|AT516615B1|2015-08-28|2015-08-28|A method for detecting a leak in a heat recovery system of an internal combustion engine|ATA50744/2015A| AT516615B1|2015-08-28|2015-08-28|A method for detecting a leak in a heat recovery system of an internal combustion engine|
    US15/754,521| US10677678B2|2015-08-28|2016-08-19|Method for detecting an unsealed location in a heat recovery system of an internal combustion engine|
    PCT/AT2016/050254| WO2017035547A1|2015-08-28|2016-08-19|Method for detecting an unsealed location in a heat recovery system of an internal combustion engine|
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