Abnormality diagnosis device for an electric pump

Abstract

An abnormality diagnosis device for an electric pump (8) that supplies a working fluid based on a command from an external device (5), the abnormality diagnosis device comprising: a revolution number detection unit that detects a revolution number of a motor (82) that drives the electric pump (8); a first abnormality pre-decision unit that decides that there is a probability of an abnormality occurring in the electric pump (8) when a state is detected in which the motor (82) is driven by a current equal to or higher than an upper limit current (Iα) used in a normal operation and the number of revolutions of the motor (82) is less than a lower limit revolution number (NL0) set based on a working fluid temperature condition; a second abnormality pre-decision unit that decides that there is a probability of an abnormality occurring in the electric pump (8) when a state is detected in which the motor (82) is driven with a current limited by a current limit value that is lower than the upper limit current (Iα), and the number of revolutions of the motor (82) is less than a predetermined number of revolutions (NL1) that is set lower than the number of revolutions lower limit (NL0) according to the limitation of the current limit value, wherein the motor (82) is stopped when it has been decided by the first abnormality pre-decision unit or the second abnormality pre-decision unit that there is a probability of an abnormality occurring in the electric pump (8), and is restarted after a predetermined time (t3) if no abnormality decision is determined, and an abnormality decision determining unit that determines that an abnormality has occurred in the electric pump (8) when the number of restarts of the engine over a lapse of a predetermined time is equal to or exceeds a predetermined number.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The present invention relates to an abnormality diagnosis apparatus and method for an electric pump that supplies a working fluid to, for example, a drive system of a vehicle. 2. Description of the state of the art

[0002] With respect to this type of electric pump, in a technique disclosed in, for example, Japanese Laid-Open (Kokai) Patent Application JP 2006-025493 A, protective control for limiting a current value with respect to a pump drive motor is performed based on a component temperature and a continuous operation time in order to prevent an abnormality caused by heat generation.

[0003] According to the disclosure of Japanese Patent Application Laid-Open (Kokai) No. 2006-025493, the electric pump is controlled so that the current rotation speed follows the rotation speed command value (target rotation speed) of the pump drive motor given from an external device, regardless of the pump side state. Therefore, in some cases, the current rotation speed may not follow the command value due to the protective control.

[0004] However, normally, according to abnormality diagnosis for the electric pump of this type, it is judged whether an abnormality occurs or not based on tracking (deviation) of the instantaneous number of revolutions with respect to the command value, and therefore, even if the electric pump operates normally, there is a possibility that an erroneous judgment is made that an abnormality occurs.

[0005] In addition, when an extremely high command value is given, for example, due to an abnormality for generating a command value or a communication abnormality between the external device and the electric pump (motor drive circuit), the instantaneous number of motor revolutions may not follow the command value, and therefore, similarly as described above, even if the electric pump operates normally, there is a possibility that an erroneous judgment that an abnormality occurs will be made.

[0006] US 2005 / 0 056 480 A1 discloses a steering device comprising a monitoring unit for detecting abnormalities of a motor of the steering device based on a rotational speed of the motor.

[0007] US 6 054 827 A discloses a control unit which detects a deviation between a motor current detection value and a desired motor current value and a detected assist steering torque and detects an abnormality when the deviation indicates an abnormal value over a given period of time.

[0008] US 2004 / 0 013 530 A1 discloses a control device for a compressor which is suitable for operating the compressor independently of a sensor temperature.

[0009] DE 60 2005 004 829 T2 discloses an electric pump group system comprising an electric motor, a hydraulic pump driven by the electric motor, which is intended to provide hydraulic power to a hydraulic device, and means for limiting the pressure of the hydraulic fluid fed from the pump into the hydraulic circuit. SUMMARY OF THE INVENTION

[0010] The present invention has been made focusing on such conventional problems, and it is an object of the present invention to provide an abnormality diagnosis apparatus for an electric pump and an abnormality diagnosis method that can prevent an erroneous decision that an abnormality occurs in a normally functioning electric pump by executing a diagnosis process taking into account factors that affect abnormality diagnosis.

[0011] This object is achieved by the features of claim 1 and 4 respectively. The subclaims clearly describe preferred developments of the invention.

[0012] In order to achieve the above object, the abnormality diagnosis device for the electric pump according to the present invention is an abnormality diagnosis device for an electric pump that supplies a working fluid based on a command from an external device, and comprises: a revolution number detection unit that detects a revolution number of a motor that drives the electric pump; a first abnormality pre-decision unit that decides that there is a probability of an abnormality occurring in the electric pump when a state is detected in which the motor is driven by a current equal to or higher than an upper limit current used in normal operation and the number of revolutions of the motor is less than a lower limit number of revolutions set based on a working fluid temperature condition; and a second abnormality pre-decision unit that decides that there is a probability of an abnormality occurring in the electric pump when a state is detected in which the motor is driven with a current limited by a current limit value lower than the upper limit current, and the number of revolutions of the motor is less than a predetermined number of revolutions set lower than the number of revolutions lower limit according to the limitation of the current limit value, wherein the first abnormality pre-decision unit or the second abnormality pre-decision unit stops a drive of the electric pump when it is decided that there is a possibility of occurrence of an abnormality in the electric pump. wherein the motor is stopped when it has been decided by the first abnormality pre-decision unit or the second abnormality pre-decision unit that there is a probability of an abnormality occurring in the electric pump, and is restarted after a predetermined time if no abnormality decision is determined, and an abnormality decision determining unit that determines that an abnormality has occurred in the electric pump when the number of restarts of the motor over a lapse of a predetermined time is equal to or exceeds a predetermined number.

[0013] Furthermore, an abnormality diagnosis method for an electric pump according to the present invention is an abnormality diagnosis method for an electric pump that supplies a working fluid based on a command from an external device t, and comprises the following steps: Detecting the number of revolutions of a motor that drives the electric pump.

[0014] Deciding that there is a probability of occurrence of an abnormality in the electric pump in a first case with a detected state in which the motor is driven by a current equal to or higher than an upper limit current used in a normal operation and the number of revolutions of the motor is less than a lower limit number of revolutions set based on a working fluid temperature condition.

[0015] Decide that the probability of occurrence of an abnormality is given in a second case with a detected state in which the motor is driven with a current limited by a current limit value lower than the upper limit current and the number of revolutions of the motor is less than a predetermined number of revolutions set lower than the number of revolutions lower limit according to the limitation of the current limit value.

[0016] Stop the motor when it is decided that there is a probability of the abnormality occurring in the electric pump, and restart the motor after a predetermined time if no abnormality decision is detected.

[0017] An abnormality determination step for determining that an abnormality has occurred in the electric pump when the number of restarts of the motor over a lapse of a predetermined time is equal to or exceeds a predetermined number. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further details, features and advantages of the invention will become apparent from the following description of embodiments with reference to the drawings.

[0019] It shows: Fig. 1 is a diagram illustrating a driving force transmission system of a vehicle having an electric pump according to an embodiment of the present invention; Fig. 2 a control block diagram of the electric pump; Fig. 3 is a timing chart illustrating how the electric pump performs an abnormality diagnosis process; Fig. 4 is a flowchart of an abnormality diagnosis process according to a first embodiment; Fig. 5 is a flowchart showing an abnormality diagnosis process according to a second embodiment; Fig. 6 is a flowchart of an abnormality diagnosis process according to a third embodiment; and Fig. 7 is a flowchart of an abnormality diagnosis process according to a fourth embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Embodiments in which the present invention is applied to an electric pump that supplies hydraulic oil (a working fluid) for lubricating and cooling a continuously variable automatic transmission for a vehicle will be described below.

[0021] In Fig. 1, an engine (internal combustion engine) 1 is connected to a continuously variable automatic transmission 4 via a torque converter 2 and a reverse / forward switching mechanism 3, which is a starting clutch mechanism.

[0022] The reverse / forward switching mechanism 3 switches between forward and reverse movement of the vehicle and includes, for example, a planetary gear train formed with a ring gear, a pinion, and a pinion carrier connected to an engine output shaft; and a sun gear connected to a transmission input shaft; a reverse brake that fixes a transmission case to the pinion carrier; and a forward clutch that connects the transmission input shaft and the pinion carrier. This reverse brake and forward clutch are switched by shift fixing by hydraulic pressure using hydraulic oil shared with the continuously variable automatic transmission 4.

[0023] The continuously variable automatic transmission 4 includes a primary pulley 41, a secondary pulley 42, and a V-belt 43 stretched between these pulleys. Rotation of the primary pulley 41 is transmitted to the secondary pulley 42 through the V-belt 43, and rotation of the secondary pulley 42 is transmitted to drive wheels to propel the vehicle for travel.

[0024] While the driving force is transmitted, a movable conical plate of the primary pulley 41 and a movable conical plate of the secondary pulley 42 are moved in a shaft direction to change the radius of the contact position with the V-belt 43, so that it is possible to change a gear ratio between the primary pulley 41 and the secondary pulley 42, that is, a revolution ratio.

[0025] A transmission mechanism 20 comprising this reverse / forward switching mechanism 3 and the continuously variable automatic transmission 4 is controlled as follows.

[0026] A CVT control unit 5, which is an external device, calculates a transmission control signal based on various signals from the vehicle. A pressure adjustment mechanism 6, which receives the transmission control signal, adjusts the discharge pressure of a mechanical pump 7 driven by the engine through each part of the transmission mechanism 20 and supplies the pressure to each part.

[0027] Further, an electric pump 8 is arranged in a passage bypassing the mechanical pump 7. The electric pump 8 is driven based on a control signal from the CVT control unit (CVTCU) 5, which serves as the external device for reducing a locking shock or shift shock upon restarting after an idle stop of the vehicle, or for lubricating or cooling each lubricated part.

[0028] In addition, if necessary, a check valve 9, which prevents backflow of the hydraulic oil during normal operation, can be arranged in a passage at an outlet of the electric pump 8. In addition, as shown by the dot-dash line in Fig. 1, a relief valve 10 which opens at a predetermined pressure or below may be provided to limit a discharge pressure from the electric pump 8 to a predetermined pressure or below.

[0029] Fig. 2 is a control block diagram of the electric pump.

[0030] The CVTCU 5 receives detection signals (vehicle speed, brake, accelerator pedal, shift position, engine speed, battery voltage, and other signals) from various sensors of the vehicle and a temperature of the hydraulic oil (oil temperature) measured by an oil temperature sensor 11, calculates a target number of revolutions of the electric pump 8 according to a vehicle running state detected based on these signals, and outputs the target number of revolutions to the electric pump 8 as a command value.

[0031] The electric pump 8 includes a pump body 81, a motor 82 that drives the pump body 81, and a motor drive circuit 83 that drives the motor 82.

[0032] The motor drive circuit 83 drives the motor 82 so that a current number of revolutions is approximated to the target number of revolutions based on the command value from the CVTCU 5, detecting the number of motor revolutions (the number of pump revolutions), and transmitting the number of motor revolutions to the CVTCU 5.

[0033] In order to prevent the occurrence of abnormality and reduction of durability due to heat generation of the electric pump 8, a current limit value of the motor 82 as shown in Fig. 3, is adjusted gradually decreasing according to an increase of a continuous operating time (or a partial temperature) after starting.

[0034] Meanwhile, in the electric pump 8, whether or not there is a probability of an abnormality occurring is determined by executing a process taking into account a current limitation of the motor and an abnormality in the command value (e.g., due to an abnormality in generating the command value or a communication abnormality between the electric pump 8 and the CVTCU 5). That is, the electric pump 8 (the motor circuit 83) has a pre-decision function for deciding whether or not an abnormality occurs.

[0035] When it is decided that there is a possibility of an abnormality occurring in the electric pump 8 (and when the abnormality is detected), a signal indicative of this decision (instead of a current revolution number signal) is transmitted to the CVTCU 5, and the drive of the motor 82 is stopped to forcibly stop the electric pump 8.

[0036] When a signal indicating that there is a possibility of an abnormality occurring in the electric pump 8 is received from the electric pump 8, the CVTCU 5 has a function of deciding whether or not the abnormality of the electric pump 8 occurs based on, for example, the oil temperature detected by the oil temperature sensor 11, and determining the decision (abnormality decision) that the abnormality occurs. Furthermore, the CVTCU 5 executes a process of, for example, maintaining the stop of the electric pump 8 when the abnormality decision of the electric pump 8 is determined, and restarting the drive after a predetermined time elapses when no abnormality decision is determined.

[0037] As described above, the electric pump 8 also has a function of making an abnormality decision according to a predetermined procedure.

[0038] Below, details of each embodiment of the abnormality diagnosis process according to a Fig. 3 shown

[0039] Time chart and flow diagrams in Fig. 4 to 8 described.

[0040] Fig. 4 illustrates an embodiment (a first embodiment) of a basic process. This process is executed in an electric pump 8 (a motor circuit 83).

[0041] In step S1, after the electric pump 8 is started, it is judged whether a predetermined time T1 in which a motor 82 is driven using an upper limit current Iα as a current limit value during normal operation has elapsed. Here, the upper limit current Iα is set as the upper limit of the current required to ensure a necessary pump discharge amount under operating temperature conditions.

[0042] Before the predetermined time T1 has elapsed, that is, when it is decided that operation using the upper limit current Iα as the current limit value continues, the flow advances to a step S2 to decide whether or not the current revolution number of the motor 82 (the number of motor revolutions = the number of pump revolutions) is less than the command value (the target revolution number) of the number of motor revolutions by a predetermined deviation or more and less than a revolution number lower limit NL0. The revolution number lower limit NL0 herein means a revolution number lower limit in an oil temperature range (e.g., from -25°C to 100°C) that ensures operation of the electric pump 8. At a low temperature, a leakage amount is generally small, friction increases, and the revolution number decreases. Therefore, the revolution number is at a limit temperature lower limit (e.g.,-25 °C) as the lower limit of the number of revolutions.

[0043] Alternatively, the command value set in the CVTCU 5 may be fixed based on a one-to-one relationship with the oil temperature, and in this case, it is also possible to estimate the oil temperature based on the command value received in the electric pump 8, and set the revolution speed lower limit based on the estimated oil temperature.

[0044] In order to increase the precision for deciding a probability of abnormality occurrence, the decision conditions further include that there is a probability of abnormality occurrence and that the number of engine revolutions is less than the command value by a predetermined deviation or more. For example, when a command value close to the number of revolutions lower limit NL0 is generated based on the oil temperature learned by CVTCU 5 at an extremely low temperature, it is considered that normal operation is performed even if the number of engine revolutions is less than the number of revolutions lower limit NL0, as long as the number of engine revolutions is within a predetermined deviation from the command value. Therefore, it is possible to avoid a decision that there is a probability of abnormality occurrence.However, the CVTCU 5 determines a final abnormality decision, and therefore, the decision condition based on the deviation from the conditions for deciding a probability of occurrence of an abnormality in the electric pump 8 may be omitted for simplicity.

[0045] If it is judged in a step S2 that the number of engine revolutions is the number of revolutions lower limit NL0 or below, it is judged that an operation is carried out normally and the operation is continued as before.

[0046] When it is decided that the number of engine revolutions is lower than the number of revolutions lower limit NL0 (and is outside the predetermined deviation), the flow advances to a step S3 to decide whether or not a predetermined time t0 for deciding the probability of occurrence of an abnormality in this state has elapsed.

[0047] When the number of engine revolutions recovers to the number of revolutions lower limit NL0 or above in the specified time t0, operation continues as before.

[0048] When the predetermined time t0 has elapsed while the number of engine revolutions is lower than the number of revolutions lower limit NL0 (and outside the predetermined deviation), it is decided that normal operation is not being performed and there is a possibility of an abnormality occurring in the electric pump 8, and the decision that there is a possibility of an abnormality occurring is notified to the CVTCU (the external device) 5 in a step S4.

[0049] Next, in step S5, the process of forcibly stopping the driving of the electric pump 8 (the motor 82) is executed. In this case, the electric pump 8 (the motor driving circuit 83) can stop the driving, and the CVTCU 5 can stop the driving of the electric pump 8 by transmitting a signal (drive value 0) to stop the driving of the electric pump 8 in response to the received decision that there is a possibility of an abnormality occurring.

[0050] When it is decided that the predetermined time T1 has elapsed after the electric pump 8 is started in step S1, that is, after an operation is switched to an operation using a current limit value (Iβ or Iγ) lower than the upper limit current Iα, the flow advances to a step S6.

[0051] In step S6, it is judged whether the number of motor revolutions has decreased to a predetermined number of revolutions NL1 or less in the case where the electric pump 8 is operated with a limited current. In this step, the predetermined number of revolutions NL1 is set to a value close to a value when the motor stops, and it is judged that the motor 82 (the pump) is currently stopping when the number of motor revolutions is the predetermined number of revolutions NL1 or less. Due to the limitation of a current in addition to the abnormality in a command value (generation abnormality or communication abnormality), even if no abnormality occurs in the electric pump 8, there is a possibility that the number of motor revolutions decreases to the number of motor revolutions in a state where the motor is stopped or about to be stopped.

[0052] If the number of engine revolutions decreases to the predetermined number of revolutions NL1 or below, and it is judged that the engine is essentially in a stopped state, the flow proceeds to step S7 to judge whether the predetermined time t1 has elapsed in this state. If the number of engine revolutions reaches the predetermined number of revolutions NL1 or above within the predetermined time t1, and the engine revolution recovers, the operation continues as before.

[0053] When it is decided in a step S7 that the number of engine revolutions is the predetermined number of revolutions NL1 or less, that is, the predetermined time t1 has elapsed while the engine stops, the flow advances to a step S8.

[0054] Similarly to steps S4 and S5, in step S8 and a step S9, a decision that the normal operation is not carried out and that there is a possibility of occurrence of an abnormality of the electric pump 8 is reported to the CVTCU (the external device) 5, and the drive of the electric pump 8 (the motor 82) is forcibly stopped.

[0055] In the process according to the first embodiment, under operating conditions using the upper limit current Iα as the current limit value, before the predetermined time T1 elapses, a required pump discharge amount is ensured under the operating conditions, even if a command value becomes excessively high, tracking of the command value of the current revolution number is delayed, and the current revolution number decreases by a predetermined deviation or more, as long as the number of motor revolutions is the revolution number lower limit NL0 or higher. Accordingly, the driving of the electric pump 8 continues as before.

[0056] Accordingly, by deciding the probability of an abnormality occurrence using the revolution speed lower limit NL0 set in consideration of the working fluid conditions (limit temperature lower limit) during use of the pump, it is possible to conventionally prevent an erroneous decision that an abnormality of the electric pump 8 occurs based on a relationship (deviation between a command value and the current revolution number), and prevent the electric pump 8 from being stopped due to the erroneous decision, and the electric pump 8 can contribute to an improvement in the operability (an increase in hydraulic pressure) of the CVT (operating device) as much as possible.

[0057] If the instantaneous number of revolutions is less than the number of revolutions lower limit NL0, the required pump discharge amount is not ensured under the above-described operating conditions, and there is a possibility of occurrence of an abnormality of the electric pump 8. However, the number of revolutions lower than the number of revolutions lower limit NL0 is not caused by an abnormality, but, for example, by an extremely low temperature at which the number of revolutions hardly increases.

[0058] Therefore, without determining an abnormality decision, it is possible to report a decision that there is a probability of an abnormality occurring to the CVTCU (the external device) 5 and leave a final abnormality decision with oil temperature information to the CVTCU (the external device) 5.

[0059] That is, in a case where there is no abnormality in the electric pump 8, it is also possible to prevent an erroneous decision resulting from a determination of the decision that an abnormality occurs in the electric pump 8.

[0060] In addition, under the operating conditions where a current limit value is limited to Iβ or Iγ after the lapse of the predetermined time T1, even if the electric pump 8 operates normally, the number of revolutions may decrease to the number of revolutions in a state where the motor is stopped or about to be stopped not only because of a drop in the number of revolutions caused by an abnormality in the command value but also because of a limitation of a motor current.

[0061] Thus, when the number of revolutions of the electric pump 8 reaches the predetermined number of revolutions NL1 or more in the predetermined time T1 and rotation is detected, it is possible to contribute to improving the operability of a CVT hydraulic pressure as much as possible by continuing the operation of the electric pump 8 as before.

[0062] Meanwhile, when it is decided that the electric pump 8 is in a stopped state after the predetermined time T1 has elapsed, it is possible to report a decision that there is a possibility of an abnormality occurring to the CVCU (the external device) 5 and leave a final abnormality decision to the CVCU (the external device) 5.

[0063] Thus, after the predetermined time T1 has elapsed, the probability of an abnormality occurring is decided based on the predetermined number of revolutions NL1 set in consideration of a limitation of a motor current, in addition to a reduction in the number of revolutions due to the abnormality in a command value and a communication abnormality. Therefore, it is possible to avoid an erroneous decision that an abnormality of the electric pump 8 occurs based only on a deviation between the command value and the current number of revolutions. Furthermore, it is possible to prevent the electric pump 8 from stopping due to the erroneous decision and to contribute to an increase in a CVT (actuator) hydraulic pressure by the electric pump 8 as much as possible.

[0064] If it is determined that an abnormality is likely to occur either before or after the specified time has elapsed, there is still a possibility that the durability of the electric pump will be affected by the motor (pump) drive. However, it is possible to prevent the influence on the durability of the electric pump by stopping the drive.

[0065] Fig. 5 illustrates an embodiment (second embodiment) of a process executed in an electric pump 8 after the process according to the first embodiment.

[0066] In a step S11, it is decided whether or not to execute the drive stop process after deciding that there is a possibility of an abnormality occurring in the electric pump 8.

[0067] When it is decided that the stop process is not executed and the electric pump 8 is operating normally, the flow advances to a step S12 to decide whether or not there is a drive instruction from the CVTCU (the external device) 5.

[0068] When a drive instruction is present, the starting of the electric pump (the motor 82) is controlled based on a command value (the target number of revolutions) in step S13. When there is no drive instruction, a normal stop process of the electric pump 8 is executed in step S14 to stop the electric pump 8.

[0069] If it is judged in step S11 that the drive stop process of the electric pump 8 (the motor 82) is being executed, the flow advances to step S15 to judge whether a predetermined time t2 has elapsed after the drive of the pump was stopped. Before the predetermined time t2 elapses, the drive stop process continues in step S16, and after the predetermined time t2 elapses, the flow advances to step S17 to cancel the drive stop process. Here, the predetermined time t2 is set to a time required for the oil temperature to rise by a predetermined temperature, and the predetermined temperature is set to, for example, a value corresponding to the change value of an oil temperature sensor 11.That is, although the command value is usually set based on the oil temperature detected by the oil temperature sensor 11 in consideration that an oil temperature detected by the oil temperature sensor varies in a range where the detected oil temperature is higher than a current oil temperature, a rise in the oil temperature corresponding to the change value is achieved when the predetermined time has elapsed.

[0070] That is, even if the target revolution number is set higher due to the above change of the oil temperature sensor to the high temperature range, the current oil temperature is low, the hydraulic oil viscosity is significant, and the rotation of the electric pump 8 hardly increases. Therefore, it can be decided that there is a possibility of an abnormality occurring. Moreover, since a motor current increases and the current is limited due to current limitation, an increase in the revolution number can be prevented. When the predetermined time t2 elapses in the above cases, the viscosity of the hydraulic oil decreases and the hydraulic oil is more easily discharged, so there is a possibility that the number of motor revolutions (the number of pump revolutions) increases to the target number of revolutions.

[0071] Therefore, the flow advances to step S12 and subsequent steps to perform control for starting the electric pump 8 or a normal stop process according to a drive instruction from the CVTCU (the external device) 5.

[0072] According to the configuration of the second embodiment, after the electric pump 8 has been forcibly stopped, a forced stop is canceled after a predetermined time has elapsed. If the number of revolutions thus increases to the number of revolutions corresponding to normal operation, such that it is not determined that there is a probability of an abnormality occurring due to an increase in the oil temperature when the time has elapsed, the operation is continued as before. That is, it is possible to loosen the restriction on starting the CVT (actuating device) in order to contribute to an improvement in functionality, while preventing an erroneous determination of an abnormality.

[0073] Fig. 6 illustrates an embodiment (third embodiment) of an abnormality diagnosis process that includes an abnormality determination in the CVT CU 5.

[0074] In a step S21, it is decided whether an electric pump 8 is forcibly stopped or not.

[0075] If the electric pump 8 is not forcibly stopped, normal control of the electric pump 8 continues in a step S22. If the electric pump 8 is forcibly stopped, the flow advances to a step S23.

[0076] In step S23, it is judged whether or not an abnormality of the pump has yet to be detected. If the abnormality is judged, the flow proceeds to step S30 to continue the process used when the pump stops. If the abnormality is not judged, the flow proceeds to step S24 to judge whether or not the pump has been forcibly stopped for the first time after the drive instruction. If not, the flow proceeds to step S30 to continue the process used when the pump stops.

[0077] When it is judged that the pump is forcibly stopped for the first time, the flow advances to a step S25 to judge whether or not a predetermined time T1 has elapsed after the pump was started.

[0078] If it is decided that T1 has yet to elapse, that is, an operation using an upper limit current Iα as a current limit value during a normal operation continues, an abnormality-deciding oil temperature is set to a predetermined temperature 1 in a step S26. If it is decided that an operation using Iβ or Iγ as a current limit value continues after T1 has elapsed, the abnormality-deciding oil temperature is set to a predetermined temperature 2 in a step S2.

[0079] Here, the preset temperature 1 and the preset temperature 2 are set as follows. Under appropriate operating conditions, friction in driving a pump due to a drop in the viscosity of the hydraulic oil is maintained at a preset value or below at the preset temperature 1 and the preset temperature 2 or above. The preset temperature 1 and the preset temperature 2 are set to limit temperatures at which the number of pump revolutions reaches or exceeds a preset number of revolutions NL0 and NL1, at which it is not judged that there is a probability of an abnormality occurring as long as the electric pump 8 operates normally. Note that the preset temperature 1 and the preset temperature 2 are set to the temperature at which the change value of the oil temperature sensor 11 in the high temperature range is added.

[0080] Next, in step S28, it is decided whether the oil temperature is lower than the abnormality-determining oil temperatures (predetermined temperature 1 and predetermined temperature 2) or not. If the oil temperature is lower than the abnormality-determining oil temperatures, in step S4 or step S8, Fig. 4, it can be decided that there is a possibility of occurrence of an abnormality due to a low oil temperature, and therefore the flow advances to a step S29 without determining an abnormality decision.

[0081] If it is decided in step S29 that there is a probability of an abnormality occurring, even if a forced stop of the electric pump 8 as shown in Fig. 5 is then canceled to restart the electric pump 8 after a predetermined time has elapsed, there is a possibility that the necessary discharge amount cannot be achieved because the number of revolutions of the electric pump 8 is sufficient or the electric pump 8 stops. Therefore, a process for limiting an operation of the CVT (e.g., setting a lower oil pressure setting) is executed.

[0082] In step S30, the process used when the pump stops is continued.

[0083] When it is decided that the oil temperature is the abnormality deciding oil temperatures (the predetermined temperature 1 and the predetermined temperature 2) or higher, it is decided that the abnormality occurs regardless of the oil temperature, that is, any abnormality such as an abnormality in a component of the electric pump 8 occurs, a diagnosis that an abnormality has occurred is determined in a step S31, and the process used when the pump stops is continued in a step S30.

[0084] According to a configuration of the third embodiment, it is possible to accurately determine an abnormality decision based on a fact that the pump rotation is normal despite an increase in the oil temperature to the abnormality-determining oil temperatures (the predetermined temperature 1 and the predetermined temperature 2) or above.

[0085] Fig. 7 illustrates an embodiment (fourth embodiment) of an abnormality diagnosis process including abnormality decision determination in an electric pump 8.

[0086] In the present embodiment, when the electric pump 8 stops while the electric pump 8 is driven in a state where a motor current is limited after a predetermined time T1 has elapsed, the limitation of the motor current is relaxed and the control for restarting the electric pump 8 is immediately executed.

[0087] The electric pump 8 is stopped in the above-mentioned state due to, for example, an abnormality in a command value (generation abnormality or communication abnormality), a limitation of an excessive current that is not suitable for a current oil temperature, or an occurrence of an abnormality in the electric pump 8.

[0088] In a step S41, after the electric pump 8 is restarted in the above-mentioned state, it is decided whether a predetermined time t3 has elapsed or not.

[0089] Immediately after the restart, it is decided that the predetermined time t3 has not elapsed, and the flow advances to step S42 to set a restart-corrected current limit value Ix. As shown by the dotted line in Fig. 3, the current limit value Ix increases to a value greater than a normal current limit value Iβ or Iγ set depending on an elapsed time after the electric pump 8 is restarted, and which is an upper limit current Iα or less. By increasing the current limit value and executing the restart process, an increase in the number of revolutions is facilitated.

[0090] Next, in step S43, while the operation using the corrected current limit value continues, it is decided whether or not restarting has been decided again, that is, whether or not it has been decided that the electric pump 8 is in a stopped state. Therefore, if the electric pump 8 does not rotate even after the restart, another decision is made as to whether to restart.

[0091] When a restart decision is made, the flow advances to a step S44 to count a restart counter 2 used during an operation in which the current limit value increases.

[0092] Next, in step S45, it is judged whether or not a restart decision number counted by the restart counter 2 has reached a predetermined number C2 or more. If it is judged that the restart decision number has reached the predetermined number C2 or more, the flow advances to step S42 to determine that an abnormality occurs in an electric pump 8 (a motor and a drive circuit) and stops the drive. If the number of pump revolutions does not increase even during operation with an increased current limit value (in a substantially stopped state), an abnormality is judged without a decision of abnormality based on the oil temperature.Even if a drop in the number of revolutions due to an abnormality in a command value (generation abnormality or communication abnormality) is considered, the motor is designed to allow rotation due to the increase in the current limit value Ix as long as the electric pump 8 operates normally, so that it is possible to determine that an abnormality occurs in the electric pump 8 even if the stopped state continues. .

[0093] When it is judged in the restart in step S41 that the electric pump 8 is rotating and the predetermined time t3 has elapsed while no abnormality is detected, the flow advances to step S47 to clear a count value of the restart counter 2.

[0094] Next, in a step S48, a current limit is reset to a current limit that does not include an increase in the current limit indicated above and is suitable for a time elapsed after a normal restart.

[0095] Similarly to step S43, in step S49, it is decided whether a restart has been decided or not when the electric pump 8 is not rotating.

[0096] When the restart is decided, the flow advances to a step S50 to count up a restart counter 1 for normal current limiting.

[0097] In step S51, it is judged whether or not the restart decision counter has reached the predetermined number C1 or more. If it is judged that the restart decision counter has reached the predetermined number C1 or more, the flow advances to step S52.

[0098] In step S52, it is reported to the CVTCU (the external device) 5 that there is a possibility of an abnormality occurring in the electric pump 8.

[0099] In a step S53, the drive of the electric pump 8 (the motor) is stopped.

[0100] When a current is limited by a normal current limit value suitable for a time elapsed after restarting, there is a possibility that the electric pump 8 will stop. Therefore, it is reported that there is a possibility of an abnormality occurring without making an abnormality decision, and the CVTCU (external device) 5 decides whether an abnormality occurs or not based on the oil temperature.

[0101] According to the fourth embodiment, by relaxing the current limit value after the restart in the electric pump 8, it is possible to make an abnormality decision as to whether the electric pump 8 rotates or not.

[0102] Although not described in the above embodiments, it should be noted that the CVTCU 5 only needs to decide that the performance tracking is deficient when the number of pump revolutions (as shown in Fig. 3 is higher than a command value (the target number of revolutions) by a predetermined deviation or more.

[0103] Although the present invention is applied to a control device for an electric pump that generates transmission hydraulic pressure in the above embodiments, the present invention is applicable to, for example, a working engine of a hybrid vehicle or a control device of an electric pump that cools, for example, an inverter, and the same effect can be achieved. In summary:

[0104] An abnormality diagnosis device for an electric pump prevents an erroneous decision that a normally operating electric pump has an abnormality. When a motor is driven by a current for driving the motor using an upper limit current Iα before a predetermined time T1 has elapsed, it is decided that there is a possibility that an abnormality occurs in the pump, and the decision is reported to an external device when the number of revolutions of the motor is less than the lower limit number of revolutions at a lower limit temperature of a hydraulic oil. When the motor is driven by limiting the current for the motor by Iβ and Iγ ( <iα) angetrieben wird, nachdem t1 abgelaufen ist, wird entschieden, dass eine wahrscheinlichkeit des auftretens einer abnormalität gegeben wenn drehung motors stoppt, und die entscheidung zur externen einrichtung gemeldet.LIST OF REFERENCE SYMBOLS 1 engine 2 torque converters 3 Reverse / forward switching mechanism 4 automatic transmissions 41 primary pulley 42 secondary pulley 43 V-belt 5 CVT control unit (CVTCU) 6 Pressure adjustment mechanism 7 mechanical pump 8 electric pump 81 Pump body 82 engine 83 Motor drive circuit, motor circuit 9 Check valve 10 Relief valve 11 Oil temperature sensor

Claims

[1] An abnormality diagnosis device for an electric pump (8) that supplies a working fluid based on a command from an external device (5), the abnormality diagnosis device comprising: a revolution number detection unit that detects a revolution number of a motor (82) that drives the electric pump (8); a first abnormality pre-decision unit that decides that there is a probability of an abnormality occurring in the electric pump (8) when a state is detected in which the motor (82) is driven by a current equal to or higher than an upper limit current (Iα) used in a normal operation and the number of revolutions of the motor (82) is less than a lower limit revolution number (NL0) set based on a working fluid temperature condition; a second abnormality pre-decision unit that decides that there is a probability of an abnormality occurring in the electric pump (8) when a state is detected in which the motor (82) is driven with a current limited by a current limit value that is lower than the upper limit current (Iα), and the number of revolutions of the motor (82) is less than a predetermined number of revolutions (NL1) that is set lower than the number of revolutions lower limit (NL0) according to the limitation of the current limit value, wherein the motor (82) is stopped when it has been decided by the first abnormality pre-decision unit or the second abnormality pre-decision unit that there is a probability of an abnormality occurring in the electric pump (8), and is restarted after a predetermined time (t3) if no abnormality decision is determined, and an abnormality decision determining unit that determines that an abnormality has occurred in the electric pump (8) when the number of restarts of the engine over a lapse of a predetermined time is equal to or exceeds a predetermined number. [2] The abnormality diagnosis device for the electric pump (8) according to claim 1, wherein, when it is judged after the restart that the predetermined time (t3) has not elapsed, the current limit value is corrected upward if the second abnormality pre-judging unit judges that there is a possibility of an abnormality occurring in the electric pump (8). [3] The abnormality diagnosis device for the electric pump (8) according to claim 1 or 2, wherein it is decided that there is a possibility of abnormality in the electric pump (8) even when a temperature of the working fluid is equal to or higher than a temperature used for deciding an abnormality. [4] An abnormality diagnosis method for an electric pump (8) that supplies a working fluid based on a command from an external device (5), the abnormality diagnosis method comprising the following steps: Detecting a number of revolutions of a motor (82) driving the electric pump (8); Deciding that there is a probability of an abnormality occurring in the electric pump (8) in a first case with a detected state in which the motor (82) is driven by a current equal to or higher than an upper limit current (Iα) used in a normal operation and the number of revolutions of the motor (82) is less than a lower limit number of revolutions (NL0) set based on a working fluid temperature condition; Deciding that the probability of an abnormality occurring in the electric pump (8) is given in a second case with a detected state in which the motor (82) is driven with a current limited by a current limit value lower than the upper limit current (Iα) and the number of revolutions of the motor (82) is less than a predetermined number of revolutions (NL1) set lower than the number of revolutions lower limit (NL0) according to the limitation of the current limit value; a step of stopping the motor (82) when it has been decided that there is a probability of occurrence of the abnormality in the electric pump (8), and restarting it after a predetermined time (t3) if no abnormality decision is determined; and an abnormality determination step for determining that an abnormality has occurred in the electric pump (8) when the number of restarts of the engine over a lapse of a predetermined time is equal to or exceeds a predetermined number. [5] The abnormality diagnosis method for the electric pump (8) according to claim 4, wherein, when it is judged after the restart that the predetermined time (t3) has not elapsed, the current limit value is corrected upward if it is judged in the second case that there is a possibility of occurrence of an abnormality in the electric pump (8). [6] The abnormality diagnosis method for the electric pump (8) according to claim 5, wherein it is decided that there is a possibility of abnormality in the electric pump (8) even when a temperature of the working fluid is equal to or higher than a temperature used for deciding an abnormality.

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