METHOD FOR DETECTING A WATER PUMP FAULT AND RECONFIGURING A POWER UNIT

Abstract

A method for detecting a malfunction of a water pump and reconfiguring an electric motor unit in an electric or hybrid motor vehicle comprising a heat transfer circuit (CC1) of the traction battery (1), the heat transfer circuit including a circulation pump for circulating heat transfer fluid in a heat exchanger (11) at the traction battery, the method comprising: 1- a step of identifying a failure of the water pump (3) of the heat transfer circuit (CC1) of the traction battery, 2- disconnecting a subset of electrical consumers not essential to mobility, 3- putting the traction battery into performance limitation mode, 4- inhibiting the electrical charging of the traction battery at a charging station, 5- providing an indication to at least one vehicle user about a vehicle malfunction. Figure 1

Description

Title of the invention: METHOD FOR DETECTING A WATER PUMP ANOMALY AND RECONFIGURATION OF A POWER UNIT

[0001] This disclosure relates generally to the field of thermal management of traction batteries in electric or hybrid vehicles. Particular interest is given to a method for detecting an anomaly in the heat transfer system that provides heating and cooling functions for the battery, including a heat transfer fluid circulation pump for circulating the heat transfer fluid in a heat exchanger at the traction battery level.

[0002] In a heat transfer fluid system for cooling a traction battery of an electric vehicle, a temperature sensor is provided in the known art. If the temperature measured by this temperature sensor exceeds a predefined high threshold, the control unit responsible for operating the cooling system reports a fault or malfunction in the traction battery cooling system.

[0003] Furthermore, when such a malfunction is detected, in the known art, the traction battery is deactivated to avoid any potential risk of thermal runaway. Consequently, for a purely electric vehicle, the vehicle is immobilized.

[0004] In this context, the inventors sought to propose a solution to improve the detection of a malfunction in the cooling system. In particular, it is desirable to improve the early detection in order to define, for the electric powertrain, a reduced-performance operating mode so as to avoid unwanted vehicle immobilization.

[0005] To achieve this objective, the invention proposes a method for detecting a malfunction of a water pump and reconfiguring an electro-motor unit, in an electric or hybrid motor vehicle comprising a traction battery heat transfer circuit, the heat transfer circuit comprising an electrically driven circulation pump for circulating heat transfer fluid at least in a heat exchanger at the traction battery level, the method comprising: 1- a step of identifying a failure of the water pump of the traction battery heat transfer circuit, 2- Disconnect a subset of electrical consumers not essential to mobility, 3- Put the traction battery into performance limitation mode, 4- Inhibit the electrical charging of the traction battery at a charging station. 5- provide an indication to at least one vehicle user about a vehicle malfunction and a trace in a non-volatile memory area of ​​faults.

[0006] Thanks to these provisions, early detection of malfunction of the water pump makes it possible in particular to anticipate an event of temperature increase and to remedy it by limiting the performance requested on the battery for the electromotor unit and by interrupting electrical consumption not essential to mobility.

[0007] The vehicle can thus continue to move and is not immobilized. This avoids a breakdown that would otherwise require the vehicle to be towed. Conversely, advantageously according to the present invention, the vehicle can be driven safely to a garage or parking area.

[0008] It is noted that the performance limitation mode concerns not only the discharge performance caused by the consumption of the traction motor, but also the recharge performance in regenerative braking circumstances.

[0009] The discharge performance limitation can be defined according to calibration tables. The same applies to the recharge performance limitation, which can be determined according to other calibration tables.

[0010] In industry terminology, the Anglo-Saxon term "derating" is used to designate the method of performance limitation.

[0011] Note that the user can be the driver of the vehicle, or a fleet manager to whom the vehicle belongs.

[0012] The term 'electrically driven circulation pump' designates an assembly comprising a pumping element itself and an electric motor coupled to this pumping element to drive it in rotation.

[0013] It should be noted that the logic presented above is not directly dependent on the measured temperature of the heat transfer fluid in the heat transfer circuit. The strategy can operate over a very wide temperature range, including during a cold start, but also during a phase of more sustained electrical and thermal stress.

[0014] According to an advantageous embodiment, the performance limitation mode determines performance limitations, in discharge and in recharge, according to one or more calibration tables.

[0015] The use of calibration tables provides great flexibility to the proposed strategy, in particular to adapt it according to the circumstantial conditions of use, according to the technological type of the battery concerned, and according to the different technical platforms of electric and hybrid vehicles.

[0016] According to one embodiment, the calibration tables are expressed according to at least two parameters, namely the current state of charge of the traction battery ('SOC') and the internal temperature of the traction battery.

[0017] According to an advantageous option, a return to normal is provided after a break in the contact and a restart of the electromotor unit.

[0018] If the water pump fault is no longer present, the operation of the electric motor unit is normal again. However, if the fault is still present, it will be detected again shortly and the performance limitation mode will be adopted again for the current driving cycle.

[0019] According to one embodiment, the electrically driven circulation pump includes a pump motor and at least one control unit is provided for controlling the pump motor, the method being characterized in that the step of identifying a failure of the water pump of the traction battery cooling circuit includes one and / or the other of the following conditions: - the control unit detects a discrepancy between a setpoint for the rotational speed and a value of the rotational speed of the pump motor returned by the water pump, said discrepancy being greater than a speed threshold for a duration greater than a first duration threshold, - if the rotational speed returned by the water pump motor is at an invalid value for a period exceeding a second time threshold, - if the control unit no longer receives information on the rotation speed of the traction battery water pump motor or if the control unit receives a continuous zero rotation speed for a period exceeding a third duration threshold.

[0020] It is noted that the drive motor of the pumping element includes a rotation speed sensor which delivers in real time the current rotation speed of the motor shaft and therefore the rotation speed of the pumping element.

[0021] According to one embodiment, the operating threshold is configurable or calibrable. According to one embodiment, the first, second, and third duration thresholds are configurable or calibrable.

[0022] These provisions provide flexibility to the proposed strategy, in particular to adapt it according to the different technical platforms of electric and hybrid vehicles, depending on the technological type of the battery.

[0023] According to one embodiment, the subset of electrical consumers not essential to mobility includes a refrigerant circuit compressor, pumps for circulating heat transfer fluid in auxiliary fluid circuits.

[0024] Certain electrical consumers may be interrupted to limit the current drawn from and supplied to the traction battery. Some Electrical consumers that can contribute to thermal stress on the heat transfer fluid circuit can be interrupted.

[0025] According to one embodiment, the subset of electrical consumers not essential to mobility is continuously redefined in real time based on temperature information in the auxiliary fluid circuits. This allows for real-time adaptation according to various parameters, such as the remaining charge in the traction battery and the general functional requirements of the vehicle.

[0026] According to one embodiment, the subset of electrical consumers not essential to mobility also includes the electrically driven circulation pump. Depending on the power limit drawn from the battery, the cooling requirement of the battery cells is lower, thereby allowing the circulation of the heat transfer fluid to be interrupted or significantly reduced, thus saving current consumed by the motor driving the pump.

[0027] According to one embodiment, the notification to a vehicle user regarding a vehicle malfunction includes at least one text message in the vehicle's instrument cluster. The vehicle driver can be informed of the reason for the performance limitation, for example, sluggish acceleration or less effective regenerative braking.

[0028] According to one embodiment, the non-volatile fault memory area can be accessed by a diagnostic tool. The after-sales network can thus know the vehicle's history of this water pump, even if the fault has disappeared at time t.

[0029] The present invention also relates to a motor vehicle comprising a traction battery heat transfer circuit, the heat transfer circuit comprising an electrically driven circulation pump for circulating heat transfer fluid at least in one exchanger at the traction battery level and at least one control unit configured to implement the method as defined above.

[0030] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates a synoptic diagram of a heat transfer circuit for the thermal management of the traction battery and other vehicle equipment involved in thermal management, the heat transfer circuit including in particular a circulation pump to circulate heat transfer fluid in thermal coupling with the traction battery; - [Fig.2] shows an example of the steps of the proposed process.

[0031] In the various figures, the same reference numerals designate identical or similar elements. For the sake of clarity, some elements are not necessarily shown to scale.

[0032] This discussion focuses on electric or hybrid vehicles equipped with a traction battery, which is necessary to ensure zero-emission operation. The motor vehicle of interest here can be of any type: passenger car, commercial vehicle, recreational vehicle, heavy goods vehicle, etc. Similarly, the traction battery can be of any technological type: for example, it can be a lithium-ion battery or any other electrochemical type.

[0033] In [Fig. 1], the traction battery is denoted 1. It is provided, as known in itself, a thermal coupling with the cells of the battery, by means of an exchanger 11 based on a heat transfer fluid which circulates in a heat transfer circuit generally denoted CCI and here named first heat transfer circuit.

[0034] The CCI heat transfer circuit performs the functions of both a cooling circuit and a heating circuit. Indeed, depending on the circumstances, the heat transfer circuit either supplies heat to the traction battery or draws heat from the traction battery.

[0035] It should be noted that the fluid circulation pump is referred to in the trade as a water pump. However, the heat transfer fluid may contain components other than water molecules, notably glycol. In practice, glycol water is very often used.

[0036] The heat transfer circuit CCI may include an expansion vessel 17 as known per se.

[0037] The CCI heat transfer circuit can operate as a local circuit in some cases. In other cases, it operates in conjunction with one or two other heat transfer circuits (referred to here as 'auxiliary') which will be detailed below.

[0038] The electrically driven circulation pump, designated 3, comprises a pumping element PI and an electric motor Ml, coupled to the pumping element PL

[0039] The electric motor includes a rotational speed sensor 9 which measures the rotational speed of the motor shaft and therefore the rotational speed of the PL pump

[0040] The electric motor is controlled in proportional mode, and not in on-or-none mode, so as to be able to rotate the pump at any rotation speed between 0 and a maximum speed.

[0041] The CCI heat transfer circuit includes a temperature sensor TS1 which measures the temperature of the heat transfer fluid in the CCI heat transfer circuit.

[0042] It is noted that the battery may also contain an internal temperature sensor.

[0043] In the illustrated example, the heat transfer circuit includes a heat exchanger 2 in thermal coupling with a refrigerant circuit. The refrigerant circuit includes an air conditioning compressor, denoted 7.

[0044] The CCI heat transfer circuit includes a 3-way valve, designated 6, which allows switching between local loop operation and loop operation general, that is to say with a circulatory coupling with the other heat transfer circuits of the vehicle.

[0045] The 3-way valve 6 comprises an inlet 61 and two outlets 62, 63.

[0046] When the 3-way valve is in the first position (arrow Fl on [Fig. 1]), the circuit CCI heat transfer fluid operates locally, whereas conversely, when the 3-way valve is in a second position (arrow F2 on [Fig.l]), the CCI heat transfer fluid flow is directed to a second CC2 heat transfer circuit.

[0047] A return circuit branch, noted 53, is provided to return heat transfer fluid from the second heat transfer circuit CC2 to the first heat transfer circuit CCI when the 3-way valve 6 is in the second position.

[0048] The second heat transfer circuit CC2 includes a heat dissipation radiator 8 coupled to a fan 18 as known per se.

[0049] The second heat transfer circuit CC2 includes a pumping element P2 driven by an electric motor M2.

[0050] The second heat transfer circuit CC2 includes a temperature sensor TS2 which measures the temperature of the heat transfer fluid in the second heat transfer circuit CC2.

[0051] The second heat transfer circuit CC2 allows in particular to cool an electric traction machine denoted MEL, a control inverter 10 of the traction machine, and optionally an on-board charger 12. It should be noted that there may be several electric machines to be cooled in the vehicle.

[0052] Furthermore, a third heat transfer circuit, designated CC3, is also planned.

[0053] This third heat transfer circuit CC3 allows heat or cold to be delivered into the passenger compartment of the vehicle.

[0054] The heat transfer circuit, denoted CC3, includes a pumping element P3 driven by an electric motor M3.

[0055] The third heat transfer circuit CC3 includes a temperature sensor TS3 which measures the temperature of the heat transfer fluid in the third heat transfer circuit CC3.

[0056] The third heat transfer circuit CC3 includes a cooled heat exchanger 4 in thermal coupling with a refrigerant circuit. The refrigerant circuit includes an air conditioning compressor, denoted 7, which may be the same as the one already mentioned.

[0057] The third heat transfer circuit CC3 includes a heat exchanger 5, with electrical resistances selectively controlled according to need, in particular for cold starts.

[0058] The third heat transfer circuit CC3 includes an exchanger 20 coupled with the passenger compartment air circuit 21.

[0059] A solenoid valve 16 is provided to connect the second heat transfer circuit and the third heat transfer circuit

[0060] A return circuit branch, noted 54, is provided to return heat transfer fluid from the third heat transfer circuit CC2 to the second heat transfer circuit CCI.

[0061] Furthermore, the thermal management system includes at least one control unit 13 responsible for monitoring the proper functioning of the first heat transfer circuit CCI. In addition, the vehicle is equipped with an instrument cluster and / or multimedia equipment, generally identified by reference numeral 14, which provides information to the driver.

[0062] Advantageously according to the present invention, the control unit 13 monitors the proper functioning of the pumping and circulation function.

[0063] For this purpose, the control unit 13 acquires the information delivered by the rotation speed sensor 9.

[0064] More specifically, the control unit is configured to implement a method intended for, on the one hand, detecting an anomaly in the operation of a water pump and, on the other hand, reconfiguring the electromotor unit.

[0065] The method includes an initial step SI of identifying a failure of the water pump 3 of the heat transfer circuit CCI.

[0066] Said water pump failure identification step 3 includes one and / or both of the following conditions: - the control unit 13 detects a difference between a setpoint speed and a pump speed value returned by the water pump exceeding a speed threshold SW for a duration exceeding a first duration threshold SI, - if the rotation speed returned by the rotation speed sensor 9 is at an invalid value for a period exceeding a second duration threshold S2, - if the control unit 13 no longer receives information on the rotation speed of the traction battery water pump or if the control unit receives a continuous zero speed for a period exceeding a third duration threshold S3.

[0067] These conditions make it possible to detect the various anomalies that may occur, such as a mechanical blockage of the pump, an intrinsic problem of the electric motor, a coupling problem between the motor and the pump, etc.

[0068] Advantageously, the SW operating threshold is configurable or calibrable. The first duration threshold SI, the second duration threshold S2, and the third duration threshold S3 are configurable or calibrable.

[0069] The process includes a step S2 of switching off a subset of electrical consumers not essential to mobility.

[0070] The subset of electrical consumers not essential to mobility includes the compressor 7 of the refrigerant circuit. The subset in question may also include pumps P2, P3 to circulate heat transfer fluid in auxiliary fluid circuits CC2 and CC3.

[0071] The subset of electrical consumers not essential to mobility also includes the electrically driven PI circulation pump; indeed, if the battery's thermal charge is within a tolerable mid-range, the circulation of the heat transfer fluid can be stopped or the pump speed reduced to a minimum. Of course, the pump can be restarted depending on the temperature of the heat transfer fluid and the internal temperature of the battery.

[0072] The subset of electrical consumers not essential to mobility is redefined continuously and in real time according to temperature information in the auxiliary fluid circuits, in particular to take into account current driving conditions and circumstances.

[0073] Performance limitation mode

[0074] When a malfunction of the water pump is detected, the operation of the electromotor unit is reconfigured, namely, more precisely, a switch to a performance limitation mode (step noted 3-).

[0075] It is noted that the performance limitation mode can affect a situation where the battery temperature is rather high but also a situation, for example in cold start, where the battery temperature is too low for it to operate at full power.

[0076] In other words, regardless of the temperature measured on the heat transfer fluid and / or inside the battery, if a malfunction of the water pump is detected, the traction battery is put into performance limitation mode.

[0077] This performance limitation method allows performance limitations to be determined from one or more calibration tables

[0078] According to one embodiment, the calibration tables are expressed according to at least two parameters, namely the current state of charge of the traction battery ('SOC') and the internal temperature of the traction battery.

[0079] A calibration table represents a power map which depends on the current state of charge (SOC) of the traction battery on the x-axis and on the internal temperature of the traction battery on the y-axis.

[0080] For example, a reduction rate of 40% to 60% of the power normally available for the traction battery can be chosen.

[0081] The performance limitations are defined on the one hand in discharge mode (current drawn from the battery) and in recharge mode (current injected back into the battery).

[0082] It is noted that the implementation of the performance limitation step can be carried out by a computer other than the control unit 13 already mentioned. It can This includes, for example, the control unit of the electromotor group identified as 15 in [Fig.1], which exchanges multiple data with the control unit 13 in charge of monitoring the water pump of the heat transfer circuit CCI.

[0083] When a malfunction of the water pump is detected, the possibility of recharging the battery from a public or private charging station is inhibited (step 4). This is because, during battery recharging, the battery must dissipate heat, and if the heat transfer circuit and its water pump are not functioning correctly, there may be an undesirable rise in temperature inside the battery, especially since the vehicle is unattended during this phase.

[0084] The method includes a step (step noted 5-) of notifying the driver or more generally a user of the vehicle.

[0085] The indication to a vehicle user about a vehicle malfunction includes at least one text message in the vehicle's instrument cluster or multimedia screen 14.

[0086] The non-volatile fault memory area can be consulted by a diagnostic tool available in maintenance garages.

[0087] When a malfunction of the water pump is detected, it is planned to record a trace in a non-volatile fault memory area, for example in the memory of the control unit 13

[0088] Generally speaking, a return to normal is expected after a power outage and a restart of the electromotor unit.

[0089] If the water pump fault is no longer present, the operation of the electric motor unit is normal again. However, if the fault is still present, it will be detected again shortly and the performance limitation mode will be adopted again for the current driving cycle.

[0090] Furthermore, it should also be noted that the numbered steps 2- to 5- can be executed in any order, or even all executed in parallel.

Claims

Demands

1. A method for detecting a malfunction of a water pump and reconfiguring an electric motor unit in an electric or hybrid motor vehicle comprising a traction battery heat transfer circuit (1), the heat transfer circuit comprising an electrically driven circulation pump (3, P1, M1) for circulating heat transfer fluid in at least one heat exchanger (11) at the traction battery, the method comprising: 1- a step of identifying a failure of the water pump (3) of the traction battery heat transfer circuit (1), 2- disconnecting a subset of electrical consumers not essential to mobility, 3- putting the traction battery into performance limitation mode, 4- inhibiting the electrical charging of the traction battery at a charging station.5- Provide an indication to at least one vehicle user regarding a vehicle malfunction and a trace of the fault in a non-volatile memory area.

2. The method according to claim 1, characterized in that the performance limitation mode determines performance limitations, in discharge and recharge, according to one or more calibration tables.

3. A method according to any one of claims 1 to 2, further comprising a return to normal after a power outage and a restart of the electromotor unit.

4. A method according to any one of claims 1 to 3, wherein the electrically driven circulation pump comprises a pump motor and at least one control unit (13) is provided for controlling the pump motor, characterized in that the step of identifying a failure of the traction battery cooling circuit water pump comprises one and / or the other of the following conditions: - the control unit detects a deviation between a set speed and a value of the pump motor speed returned by the water pump, said deviation being greater than one - if the rotation speed returned by the water pump motor is at an invalid value for a period exceeding a second duration threshold, - if the control unit no longer receives information on the rotation speed of the traction battery water pump motor or if the control unit receives a continuous zero speed for a period exceeding a third duration threshold.

5. Method according to claim 4, characterized in that the regime threshold is parameterizable or calibrable, and the first, second and third duration thresholds are parameterizable or calibrable.

6. A method according to any one of claims 1 to 5, characterized in that the subset of electrical consumers not essential to mobility includes a refrigerant circuit compressor, pumps for circulating heat transfer fluid in auxiliary fluid circuits.

7. The method according to claim 6, characterized in that the subset of electrical consumers not essential to mobility is continuously and in real time redefined as a function of temperature information in the auxiliary fluid circuits.

8. Method according to claim 6, characterized in that the subset of electrical consumers not essential to mobility also includes the electrically driven circulation pump.

9. A method according to any one of claims 1 to 8, characterized in that the indication to a vehicle user about a vehicle malfunction includes at least one text message in the vehicle's instrument cluster.

10. Motor vehicle comprising at least one traction battery heat transfer circuit (HTC), the heat transfer circuit comprising an electrically driven circulation pump (3,P1,M1) for circulating heat transfer fluid at least in one heat exchanger (11) at the traction battery and at least one control unit (13) configured to implement the method according to any one of claims 1 to 9.

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