• 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 (WHR), in particular an internal combustion engine, wherein the heat recovery system (WHR) has at least one working medium circuit with at least one pump (P) and at least one expansion machine (E). In order to detect leaks in the heat recovery system early and reliably, a mass flow (mP) is determined by the pump (P) and a mass flow (mE) by the expansion machine (E). The determined mass flows (mP, mE) through the pump (P) and through the expansion machine (E) are compared. A leak between pump (P) and expansion machine (E) is detected when the mass flow (mP) by the pump (P) from the mass flow (mE) through the expansion machine (E) - preferably for a defined delay period (t) - deviates and the deviation is greater than a defined threshold (S).
    公开号:AT513205A1
    申请号:T50294/2012
    申请日:2012-07-24
    公开日:2014-02-15
    发明作者:Klemens Dipl Ing Neunteufl；Stefan Dipl Ing Krapf；Philip Dr Stevenson；Helmut Dipl Ing Theissl
    申请人:Avl List Gmbh；
    IPC主号:
    专利说明:

    1 56459
    The invention relates to a method for detecting a leak in a heat recovery system, in particular an internal combustion engine, wherein the heat recovery system has at least one working medium circuit with at least one pump and at least one expansion machine.
    When operating a heat recovery system in conjunction with an internal combustion engine, detecting leaks in the system is a 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 the working fluid into the internal combustion engine - causes damage, for example, when the working fluid enters the combustion chamber via EGR evaporator (EGR = Exhaust Gas Recirculation). • 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. 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. 2/16 2
    Known methods have the disadvantage that they can either be performed only in the deactivated state and / or that additional devices such as sensors or the like are required.
    The object of the invention is to be able to detect leaks in the heat recovery system early and reliably in the simplest possible way.
    According to the invention, this is done by > that a mass flow is determined by the pump, > that a mass flow is detected by the expansion machine, and > that the determined mass flows are compared by the pump and by the expansion machine, and that a leakage between the pump and the expansion machine is detected, when the mass flow through the pump from the mass flow through the expansion machine - preferably for a defined delay time - deviates and the deviation is greater than is a defined threshold.
    In particular, when a metering pump is used to set a defined working media mass flow as the pump, leaks between the pump and the expansion machine can be detected in this way with little effort.
    If the pump is a feed pump, then a control valve between the pump and expander is required for metering the working fluid. In this case, it is advantageous if a mass flow is determined by the control valve. In this case, the determined mass flows are compared by the pump and the control valve. If the mass flows deviate from one another-preferably for a defined first delay duration-and the deviation is greater than a defined first threshold value, a leak between the pump and the control valve can be established. Likewise, the determined mass flows through the control valve and the expansion machine can be compared with each other, and a leakage between the control valve and expansion machine can be determined if the two mass flows from each other - preferably for a defined second delay duration - deviate and the deviation is greater than a defined second threshold is.
    The mass flows can be determined particularly easily by modeling.
    Thus, the mass flow through the pump can be determined from the speed of the pump and the pressure downstream of the pump by means of a first mathematical model. Furthermore, the mass flow can be determined by the control valve from the current valve opening and the pressure before and after the control valve by means of a second mathematical model. The mass flow through the expansion machine can be determined from at least the pressure and the temperature upstream of the expansion machine and the speed of the expansion machine by means of a third mathematical model.
    The heat recovery system can be operated as a closed or open circuit.
    Compared with the prior art, the method according to the invention has the advantage that no further sensors are necessary, since all sensors used in the method, such as pressure sensors, temperature sensors, rotational speed sensors, are already standard components in heat recovery systems.
    The invention will be explained in more detail below with reference to FIG.
    2 shows the method according to the invention, FIG. 3 a first mathematical model, FIG. 4 a pump characteristic diagram, FIG. 5 a second mathematical model, FIG. 6 a valve characteristic, FIG Fig. 7 is a third mathematical model, Fig. 8 is an expander map, and Fig. 9 is an expander correction map.
    DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The heat recovery system WHR shown in detail in FIG. 1 for an internal combustion engine has a pump P which is designed, for example, as a feed pump for a working medium, an expansion machine E and at least one control valve V arranged between the pump P and the expansion machine E. 4/16 4
    According to the method proposed here for detecting leaks in the heat recovery system WHR, a mass flow mP is determined by the pump P, a mass flow mv by the control valve V and a mass flow mE by the expansion machine E. The determination of the mass flows mP, mv and mE via first, second and third mathematical models MP, Mv and ME.
    According to the first mathematical model MP, the mass flow mP = mP (nP, pP) is determined by the pump P from the speed nP of the pump P and the pressure pP after the pump P, as indicated schematically in FIG. In this case, based on the pressure Pp after the pump P and the rotational speed nP of the pump P, a pump coefficient kP is determined on the basis of the pump characteristic field PK shown in FIG. 4 and the mass flow mP is determined by the pump P taking into account the density p of the working medium.
    The mass flow mv = mv (A, pvi, pV2) through the control valve V is determined by means of the second mathematical model Mv shown in FIG. 5 from the current valve opening A and the pressures pVi, Pv2 before and after the control valve V. In this case, a flow coefficient kA is determined from the valve characteristic VK shown in FIG. 6, and the mass flow mv is determined by the control valve V taking into account the density p of the working medium
    The mass flow mE = mE (nE, pE, TE) by the expansion machine E is with the third mathematical model ME from the speed nE of the expansion machine E, the pressure pE before the expansion machine E by means of an expander map KE shown in FIG 9 expander correction map KEK and the temperature TE before the expansion machine E determined as Fig. 7 demonstrates. A base mass flow mEb determined from the expander characteristic field KE is corrected by the correction factor ek obtained by the correction characteristic field KEK and the temperature TE in front of the expansion machine E, and the mass flow mE is determined therefrom by the expansion machine E.
    The illustrated mathematical models are exemplary only. Of course, other models are usable.
    Thereafter, the determined mass flows mP, mv and mE are compared. 5/16 5
    If the difference Ami of the mass flow mP from the pump P and the mass flow mv through the control valve V exceeds a first threshold value Si for longer than a first delay time ti, then a leakage LI between the pump P and the control valve V is detected. If the difference Am2 of the mass flow mv through the control valve V and the mass flow mE into the expansion engine E exceeds a second threshold value S2 for longer than a delay time t2, a leakage L2 between the control valve V and expander E is detected.
    If the pump P is designed as a metering pump, then it can be used to set a defined working media mass flow, whereby the control valve V can be omitted. In this case, only the mass flow mP by the pump P and the mass flow mE by the expansion machine E needs to be determined and compared with each other. A leak between the pump P formed as a metering pump and the expansion machine E can be determined when the mass flow mP by the pump P from the mass flow mE by the expansion machine E deviates for a defined delay duration and the deviation is greater than a defined threshold S.
    The described method has the advantage that a continuous check of the heat recovery system WHR for leakage during operation can be carried out, it being possible to work with the usual standard system sensor system. 6/16
    权利要求:
    Claims (10)
    [1]
    1. A method for detecting a leak in a heat recovery system (WHR), in particular an internal combustion engine, wherein the heat recovery system (WHR) at least one working medium circuit with at least one pump (P) and at least one expansion machine (E), characterized, a , that a mass flow (mP) is determined by the pump (P), b. that a mass flow (mE) is determined by the expansion machine (E), and c. that the determined mass flows (mP, mE) by the pump (P) and by the expansion machine (E) are compared with each other, and that a leak between the pump (P) and expander (E) is determined when the mass flow (mP) through the pump (P) deviates from the mass flow (mE) by the expansion machine (E) - preferably for a defined delay duration (t) - and the deviation is greater than a defined threshold value (S).
    [2]
    2. The method of claim 1 with a between the pump (P) and the expander (E) arranged control valve (V), characterized in that a mass flow (mv) by the control valve (V) is determined.
    [3]
    3. The method according to claim 2, characterized in that the determined mass flows (mP, mv) by the pump (P) and by the control valve (V) are compared with each other, and that a leak (LI) between the pump (P) and control valve (V) is determined when the mass flow (mP) by the pump (P) from the mass flow (mv) by the control valve (V) - 7/16 7 preferably for a defined first delay period (ti) -abweicht and the deviation greater than is a defined first threshold (Si).
    [4]
    4. The method according to claim 2 or 3, characterized in that the determined mass flows (mv, mE) by the control valve (V) and by the expansion machine (E) are compared with each other, and that a leak (L2) between the control valve (V) and expansion machine (E) is determined when the mass flow (mE) by the expansion engine (E) from the mass flow (mv) through the control valve (V) - preferably for a defined second delay period (t2) - deviated and the deviation greater than a defined Threshold (S2) is.
    [5]
    5. The method according to any one of claims 1 to 4, characterized in that the mass flow (mP) by the pump (P) from the speed (nP) of the pump (P) and the pressure (pP) to the pump (P) by means of a first mathematical model (MP) is determined.
    [6]
    6. The method according to any one of claims 1 to 5, characterized in that the mass flow (mv) by the control valve (V) from the current valve opening (A) and the pressures (pvi, pV2) before and after the control valve (V) by means of a second mathematical model (Mv) is determined.
    [7]
    7. The method according to any one of claims 1 to 6, characterized in that the mass flow (mE) by the expansion machine (E) from at least the pressure (pE) and the temperature (TE) before the expansion machine (E), as well as the speed ( nE) of the expansion machine (E) by means of a third mathematical model (M3) is determined.
    [8]
    8. The method according to any one of claims 1, 5 or 7, characterized in that as a pump (P) a metering pump is used for setting a defined working media mass flow.
    [9]
    9. The method according to any one of claims 1 to 8, characterized in that the heat recovery system (WHR) is operated in a closed circuit. 8/16 8
    [10]
    10. The method according to any one of claims 1 to 8, characterized in that the heat recovery system (WHR) is operated in an open circuit. 2012 07 24 feet 9/16
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    同族专利:
    公开号 | 公开日
    AT513205B1|2014-05-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3416500A|1966-12-28|1968-12-17|Combustion Eng|Method and system for detecting leaks in a forced through flow steam generator plant|
    DE4420476A1|1992-09-22|1995-12-14|Joseph Baumoel|Pipeline leak detecting and temp modelling appts|
    US6526358B1|1999-10-01|2003-02-25|General Electric Company|Model-based detection of leaks and blockages in fluid handling systems|
    DE102010054736A1|2010-12-16|2012-06-21|Daimler Ag|Steam power plant for motor car, has device arranged in closed circuit such that device detects leakage of closed circuit in rest state of power plant, where device comprises pressure sensor and temperature sensor|US10364768B2|2014-12-05|2019-07-30|Robert Bosch Gmbh|Method for operating an arrangement for using waste heat|
    AT516701B1|2015-01-28|2016-08-15|Avl List Gmbh|METHOD FOR DETECTING A LEAKAGE IN A HEAT RECOVERY SYSTEM|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50294/2012A|AT513205B1|2012-07-24|2012-07-24|Method for detecting a leak in a heat recovery system|ATA50294/2012A| AT513205B1|2012-07-24|2012-07-24|Method for detecting a leak in a heat recovery system|
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