Patent Application
20060149433
1. Field of Invention
The invention relates to a failure diagnosing device and method for a vehicular control apparatus, which determines that a failure has occurred in a control apparatus mounted on a vehicle, when a continuation quantity of an operation state of the control apparatus, in which a predetermined failure precondition is satisfied, exceeds a predetermined failure determination threshold value. More particularly, the invention relates to a technology for preventing the failure diagnosing device and method from making an erroneous determination regarding a failure, and for improving sensitivity of a failure determination, by correcting the failure determination threshold value based on the continuation quantity of the operation state in which the predetermined failure precondition is satisfied.
2. Description of Related Art
There is a known vehicle provided with a failure diagnosing device which determines whether a failure has occurred in a control apparatus mounted on the vehicle. For example, the failure diagnosing device determines that a failure has occurred in the control apparatus when a predetermined failure precondition, which is satisfied only when a failure occurs, is satisfied. However, in an actual operation of the control apparatus, the failure precondition is satisfied even when the control apparatus is operating normally, depending on contents of the failure precondition. Therefore, there is a possibility to erroneously determine that a failure has occurred in the control apparatus, even when the control apparatus is operating normally. Accordingly, in order to avoid such an erroneous determination, there is proposed a technology for determining that a failure has occurred when the continuation quantity of the operation state, in which the failure precondition is satisfied, exceeds a predetermined failure determination threshold value, e.g. a predetermined time. For example, as shown in Japanese Patent Laid-Open Publication No. JP-A-11-287319, there is a technology for making a failure determination, in consideration of delay in response due to a time lag between when a shifting command is issued and when shifting is completed, in shift control of an automatic transmission. According to the technology, a determination, that a failure has occurred in the control apparatus, is made when the continuation quantity of the operation state, in which the failure precondition is satisfied, exceeds the predetermined period. Namely, a determination, that a failure has occurred in the control apparatus, is made when the period, in which a gear ratio of a shifting command disagrees with an actual gear ratio, exceeds the predetermined period.
However, in order to prevent an erroneous determination due to a driving operation, a running condition, and individual differences such as variations of vehicles, it is necessary to set the failure determination threshold value and the failure precondition with leeway. Accordingly, there is a possibility that the sensitivity of a failure determination is reduced. Namely, prevention of an erroneous determination regarding a failure and prevention of reduction in the determination sensitivity are incompatible with each other. Therefore, it is difficult to prevent both an erroneous determination regarding a failure and reduction in the determination sensitivity.
It is an object of the invention to provide a failure diagnosing device and method for a vehicular control apparatus, which determines that a failure has occurred in the control apparatus mounted on a vehicle, when a continuation quantity of an operation state of the control apparatus, in which a predetermined failure precondition is satisfied, exceeds a predetermined failure determination threshold value. More particularly, it is an object of the invention to provide a failure diagnosing device and method for a vehicle, which is prevented from making an erroneous determination regarding a failure and whose sensitivity of the failure determination is improved, by correcting a failure determination threshold value based on a continuation quantity of an operation state in which a predetermined failure precondition is satisfied.
According to a first aspect of the invention, there is provided a failure diagnosing device for a vehicular control apparatus, which includes (a) failure determining means for determining that a failure has occurred in the control apparatus when a continuation quantity of an operation state of the control apparatus, in which a predetermined failure precondition is satisfied, exceeds a predetermined failure determination threshold value, characterized by including (b) failure determination threshold value correcting means for correcting the failure determination threshold value based on an actual continuation quantity of the operation state.
Thus, the failure determination threshold value, which is used for determining whether a failure has occurred in the control apparatus by the failure determining means, is corrected by the failure determination threshold value correcting means based on the continuation quantity of the operation state of the control apparatus, in which the predetermined failure precondition is satisfied. Accordingly, it is possible to make a failure determination by the failure determining means using the failure determination threshold value which is set in consideration of the individual differences such as variations of vehicles. As a result, it is possible to prevent an erroneous determination regarding a failure, and to improve the sensitivity of the failure determination.
In this case, correction by the failure determination threshold value correcting means is preferably performed based on the continuation quantity of the operation state where the control apparatus is operating normally and the continuation quantity is smaller than the failure determination threshold value. Thus, the failure determination threshold value is appropriately corrected by the failure determination threshold value correcting means. As a result, an erroneous determination regarding a failure by the failure determining means is prevented, and the sensitivity of the failure determination is improved.
It is also preferable that the failure diagnosing device include (a) storing means for storing the actual continuation quantity, and (b) the failure determination threshold value correcting means correct the failure determination threshold value based on a storage value stored in the storing means. Thus, correction of the failure determination threshold value by the failure determination threshold value correcting means is appropriately performed based on the actual continuation quantity.
It is also preferable that the failure diagnosing device include (a) continuation quantity detecting means for detecting an actual continuation quantity of the operation state of the control apparatus each time when the predetermined failure precondition is satisfied, and (b) smoothing means for smoothing fluctuation in the continuation quantity of the operation state which is repeatedly detected by the continuation quantity detecting means, and (c) the storing means store a smooth processed value obtained by the smoothing means. Thus, it is possible to appropriately correct the failure determination threshold value using the failure determination threshold value correcting means, based on the smooth processed value which is obtained, using the smoothing means, by smoothing the fluctuation in the actual continuation quantity of the operation state, the fluctuation being due to causes other than individual differences such as variations of vehicles, for example, the fluctuation being due to causes such as the driving operation and the running condition.
It is also preferable that the continuation quantity be the duration of the operation state in which the predetermined failure precondition is satisfied, and the storing means store the number of times that the actual continuation quantity or the smooth processed value exceeds the predetermined time. Thus, the number of times that actual continuation quantity or the smooth processed value exceeds the predetermined time is stored in the storing means. As a result, it is possible to reduce the amount of information to be stored in the storing means, thereby preventing garbling of the storage value and/or deterioration of durability of the storing means.
It is also preferable that the continuation quantity be the duration of the operation state in which the predetermined failure precondition is satisfied, and the storing means store the actual continuation quantity or the smooth processed value which exceeds the predetermined time. Thus, since only the actual continuation quantity or the smooth processed value which exceeds the predetermined time is stored in the storing means. As a result, it is possible to reduce the amount of information to be stored in the storing means, thereby preventing garbling of the storage value and/or deterioration of durability of the storing means.
It is also preferable that the storing means store the maximal value of the actual continuation quantity or the maximal value of the smooth processed value. Thus, since only the maximal value of the actual continuation quantity or the maximal value of the smooth processed value is stored in the storing means. As a result, it is possible to reduce the amount of information to be stored in the storing means, thereby preventing garbling of the storage value and/or deterioration of durability of the storing means.
It is also preferable that the failure determination threshold value correcting means do not correct the failure determination threshold value when a failure determination for the control apparatus is not performed by the failure determining means. Thus, the failure determination threshold value is corrected by the failure determination threshold value correcting means only when a failure determination for the control apparatus is performed. As a result, it is possible to appropriately determine whether a failure has occurred in the control apparatus.
It is also preferable that the storing means do not store the actual continuation quantity or the smooth processed value when a failure determination for the control apparatus is not performed by the failure determining means. Thus, the actual continuation quantity or the smoothing value stored in the storing means does not include the actual continuation quantity or the smooth processed value when a failure determination for the control apparatus is not performed. As a result, it is possible to appropriately correct the failure determination threshold value using the failure determination threshold value correcting means, and to appropriately determine whether a failure has occurred in the control apparatus.
It is also preferable that the control apparatus be a power transmission system which transmits power of an engine to drive wheels. For example, it is appropriately determined whether a failure has occurred in a solenoid valve which controls shifting of an automatic transmission as the power transmission system and hydraulic pressure of a lock-up clutch provided in a torque converter.
According to a second aspect of the invention, there is provided a failure diagnosing method for a vehicular control apparatus, which includes (a) failure determining step for determining that a failure has occurred in the control apparatus when a continuation quantity of an operation state of the control apparatus, in which a predetermined failure precondition is satisfied, exceeds a predetermined failure determination threshold value, characterized by comprising the step of: (b) correcting the failure determination threshold value based on an actual continuation quantity of the operation state.
The foregoing and further objects, features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:
Hereafter, an embodiment of the invention will be described in detail with reference to accompanying drawings.
The automatic transmission 16 is a planetary gear type transmission which includes a first planetary gear drive 40, that is the double pinion type, and a second planetary gear drive 42, and a third planetary gear drive 44, that are the single pinion type. A sun gear S1 of the first planetary gear drive 40 is selectively coupled to the input shaft 22 via a clutch C3, and is selectively coupled to a housing 38 via a one way clutch F2 and a brake B3, whereby rotation in the reverse direction (the direction opposite to direction in which the input shaft 22 rotates) is inhibited. A carrier CA1 of the first planetary gear drive 40 is selectively coupled to the housing 38 via a brake B1, and rotation in the reverse direction is inhibited at all times by a one way clutch F1 provided in parallel with the brake B1. A ring gear R1 of the first planetary gear drive 40 is integrally coupled to a ring gear R2 of the second planetary gear drive 42, and is selectively coupled to the housing 38 via a brake B2. A sun gear S2 of the second planetary gear drive 42 is integrally coupled to a sun gear S3 of the third planetary gear drive 44. The sun gear S2 of the second planetary gear drive 42 is selectively coupled to the input shaft 22 via a clutch C4, and is selectively coupled to the input shaft 22 via a one way clutch F0 and a clutch C1, whereby the sun gear S2 is inhibited from relatively rotating in the reverse direction with respect to the input shaft 22. A carrier CA2 of the second planetary gear drive 42 is integrally coupled to a ring gear R3 of the third planetary gear drive 44. The carrier CA2 of the second planetary gear drive 42 is selectively coupled to the input shaft 22 via a clutch C2, and is selectively coupled to the housing 38 via a brake B4, whereby the carrier CA2 is inhibited from rotating in the reverse direction at all times by a one way clutch F3 provided in parallel with the brake B4. A carrier CA3 of the third planetary gear drive 44 is integrally coupled to an output shaft 46.
The clutches C1 to C4 and the brakes B1 to B4 (hereinafter, simply referred to as “clutches C2” and “brakes B”, respectively, when not specified further) are hydraulic friction engaging devices, the clutches C being, for example, multi-disc clutches and the brakes B being, for example, multi-disc brakes which are controlled by hydraulic actuators. These clutches C and brakes B are switched between an engaged/applied state and a disengaged/released state, as shown in
The hydraulic pressure control circuit 98 in
The ECU 90 includes a microcomputer that has a CPU, RAM, ROM, an input/output interface and the like. The CPU performs output control of the engine 12, shift control of the automatic transmission 16, lock-up clutch control of the lock-up clutch 26 and the like by processing signals according to a program stored in the ROM in advance while using the temporary storage function of the RAM. When necessary, the CPU may be configured such that a portion thereof for engine control is separated from a portion thereof for shift control.
In the output control of the engine 12, opening/closing of the electronic throttle valve 56 is controlled by the actuator 54. Also, a fuel injection device 92 is controlled for controlling the fuel injection amount, an ignition device 94, e.g. an igniter, is controlled for controlling the ignition timing, and the ISC valve 53 is controlled for controlling the idle speed. In the control of the electronic throttle valve 56, for example, the throttle actuator 54 is driven based on the actual accelerator pedal operation amount ACC according to the relationship between the accelerator pedal operation amount ACC and the throttle valve opening amount θTH, shown in
In the shift control of the automatic transmission 14, the shift speed of the automatic transmission 14 to be achieved is decided based on the actual throttle valve opening amount θTH and the vehicle speed V using, for example, the shift diagram (shift map), which is stored in advance, shown in
When the shift lever 72 is operated to the “D” position or the “S” position, that are the forward running positions, the forward running circuit is mechanically realized by changing the hydraulic circuit using the manual valve according to the operation of the shift lever 72. Thus, it is possible to run forward while performing shifting among the forward shift speeds, the first shit speed “1st” to the sixth shift speed “6th”. When the shift lever 72 is operated to the “D” position, the operation of the shift lever to the “D” position is determined according to a signal from the lever position sensor 74, and an automatic shift mode is realized, and shift control is performed using all the forward shift speeds from the first shift speed “1st” to the sixth shift speed “6th”. Namely, in order to avoid occurrence of shift shocks such as a change in the drive force and deterioration of a frictional member, by switching the solenoid valves Sol1 to Sol5 and the linear solenoid valves SL1 and SL2 between the energized state and the de-energized state, the hydraulic pressure control circuit 98 is changed and one of the forward shift speeds from the first shift speed “1st” to the sixth shift speed “6th” is achieved. In
When the shift lever 72 is operated to the “S” position, the operation of the shift lever 72 to the “S” position is determined according to a signal from the lever position sensor 74, and the manual shift mode is realized. The “S” position is formed at the same position as the “D” position in the longitudinal direction of the vehicle, and is formed adjacent to the “D” position in the width direction of the vehicle. When the shift lever 72 is at the “S” position, the hydraulic circuit is the same as that when the shift lever 72 is at the “D” position. However, the manual shift mode is electrically realized. In the manual shift mode, it is possible to arbitrarily select a plurality of shift ranges decided among the shift speeds which can be achieved at the “D” position, that is, among the first shift speed “1st” to the sixth shift speed “6th”. In the “S” position, an upshift position “+” and a downshift position “−” are formed in the longitudinal direction of the vehicle. When the shift lever 72 is operated to the upshift position “+” or the downshift position “−”, the operation of the shift lever 72 to the upshift position “+” or the downshift position “−” is detected by the upshift switch 80 or the downshift switch 82. Then, one of the six shift ranges “D”, “5”, “4”, “3”, “2” and “L” whose highest shift speeds, that are, the high speed side shift ranges, where the gear ratios are small, are different from each other, is electrically realized according to the upshift command RUP or the downshift command RDN. Also, shift control is automatically performed according to, for example, the shift map shown in
In the lock-up clutch control of the lock-up clutch 26, the engagement torque, that is, the engagement force of the lock-up clutch 26 can be continuously controlled. The ECU 90 functionally includes lock-up clutch control means 100 for controlling the engaged state of the lock-up clutch 26 according to the map having the disengagement range, the slip control range, and the engagement range, which is stored in advance using the throttle valve opening amount θTH and the vehicle speed V as parameters, as shown in FIG 7. In order to make the rotational speed difference (slip amount) NSLP between the turbine rotational speed NT and the engine rotational speed NE (=NE−NT) equal to the target rotational speed difference (target slip amount) NSLP*, the ECU 90 outputs a drive duty ratio DSLU which is a drive signal for the solenoid valve SLU for controlling the pressure difference ΔP of the lock-up clutch 26. In the slip control, the lock-up clutch 26 is maintained in the slip state in order to suppress a loss in power transmission of the torque converter 14 as effectively as possible while absorbing fluctuation in the rotational speed of the engine 10, thereby enhancing the fuel efficiency as effectively as possible without deteriorating drivability. In the slip control, the deceleration running time slip control is performed, for example, in the shift speed where the reverse input from the drive wheel side, that is caused during forward running when the throttle valve opening amount θTH, is substantially “0” and the vehicle is idle running (deceleration running), is transmitted to the engine 12 side, that is, the shift speed where the engine brake effect can be obtained. The turbine rotational speed NT and the engine rotational speed NE are moderately decreased in accordance with deceleration of the vehicle in the state where the rotational speed difference NSLP is made substantially equal to the target rotational speed difference NSLP*, e.g. −50 rpm through the feedback control using the drive duty ratio DSLU for the solenoid valve SLU. As mentioned above, when the lock-up clutch 26 is slip-engaged, the engine rotational speed NE is increased to a value substantially equal to the turbine rotational speed NT. Therefore, the fuel cut range (vehicle speed range), where the fuel supply to the engine 12 is stopped, is extended, and therefore the fuel efficiency is enhanced.
The lock-up relay valve 250 includes a first spool valve element 204 and a second spool valve element 206 which can contact each other and between which a spring 202 is provided; an oil chamber 208 which is provided on the shaft end side of the first spool valve element 204, and which is supplied with the control pressure PSLU for urging the first spool valve element 204 and the second spool valve element 206 to the engagement (ON) side position; and an oil chamber 210 which is supplied with the second line pressure PL2 for urging the first spool valve element 204 and the second spool valve element 206 to the disengagement (OFF) side position. When the first spool valve element 204 is at the disengagement side position, the second line pressure PL2 supplied to an input port 212 is supplied from a disengagement side port 214 to the disengagement side oil chamber 34 of the torque converter 14, and the operating oil in the engagement side oil chamber 32 of the torque converter 14 is discharged to a cooler bypass valve 224 or an oil cooler 226 through an engagement side port 220 and a discharge port 222. Thus, the engagement pressure of the lock-up clutch 26, that is the pressure difference ΔP (=hydraulic pressure in the engagement side oil chamber 32−hydraulic pressure in the disengagement side oil chamber 34) is decreased. On the other hand, when the first spool valve element 204 is at the engagement side position, the second line pressure PL2 supplied to the input port 212 is supplied from the engagement side port 220 to the engagement side oil chamber 32 of the torque converter 14, and the operating oil in the disengagement side oil chamber 34 of the torque converter 14 is discharged through the disengagement side port 214, a discharge port 228, a control port 230 of the lock-up control valve 252, and a discharge port 232, whereby the engagement pressure of the lock-up clutch 26 is increased.
Therefore, when the control pressure PSLU is equal to or lower than a predetermined value β (refer to
The lock-up control valve 252 controls the slip amount NSLP of the lock-up clutch 26 according to the control pressure PSLU and engages the lock-up clutch 26 when the lock-up relay valve 250 is at the engagement side position. The lock-up control valve 252 includes a spool valve element 234; a plunger 236 which contacts the spool valve element 234, and supplies pressing force to the spool valve element 234 for moving to the discharge side position, which is on the left side with respect to the center line of the lock-up control valve 252 shown in
Therefore, when the spool valve element 234 is brought to the discharge side position, communication is provided between the control port 230 and the discharge port 232. Accordingly, the engagement pressure is increased, and the engagement torque of the lock-up clutch 26 is increased. On the other hand, when the spool valve element 234 is brought to the supply side position, communication is provided between the supply port 246, to which the first line pressure PL1 is supplied, and the control port 230. Accordingly, the first line pressure PL1 is supplied to the disengagement side oil chamber 34 of the torque converter 14, the engagement pressure is decreased, and the engagement torque of the lock-up clutch 26 is decreased.
When the lock-up clutch 26 is disengaged, the linear solenoid valve SLU is driven by the ECU 90 such that the control pressure PSLU becomes a value smaller than the predetermined value β. On the other hand, when the lock-up clutch 26 is engaged, the linear solenoid valve SLU is driven by the ECU 90 such that the control pressure PSLU becomes the maximal value. When the lock-up clutch 26 is brought to the slip state, the linear solenoid valve SLU is driven by the ECU 90 such tat the control pressure PSLU becomes a value between the predetermined value β and the maximal value. In the lock-up control valve 252, the hydraulic pressure PON in the engagement side oil chamber 32 and the hydraulic pressure POFF in the disengagement side oil chamber 34 of the torque converter 14 are changed according to the control pressure PSLU. Accordingly, the engagement torque of the lock-up clutch 26, corresponding to the engagement pressure, that is, the pressure difference ΔP between the hydraulic pressure PON and the hydraulic pressure POFF (PON−POFF) is changed according to the control pressure PSLU, whereby the slip amount NSLP is controlled.
In
Continuation quantity detecting means 102 includes failure precondition state value obtaining means 104, failure precondition satisfaction determining means 106, and failure precondition continuation quantity measuring means 108. The continuation quantity detecting means 102 determines whether a predetermined failure precondition for the control apparatus is satisfied, and detects the continuation quantity qNG of the operation state of the control apparatus each time when the failure precondition is satisfied.
The failure precondition state value obtaining means 104 obtains a failure precondition state value indicative of the present vehicle state which is required for determining whether the predetermined failure precondition is satisfied. The predetermined failure precondition is used for making a failure determination for the vehicular control apparatus, and is the failure precondition which is used for determining the occurrence of a failure when the failure occurs in the control apparatus. For example, in the case where control is performed by the lock-up clutch control means such that the power transmission system as the vehicular control apparatus, e.g. the lock-up clutch 26 is fully engaged, a failure occurs when the rotational speed difference (slip amount) NSLP between the turbine rotational speed NT and the engine rotational speed NE (=NE−NT) occurs, that is the rotational speed difference NSLP is not substantially “0” while the drive duty ratio DSLU, that is the drive signal for the solenoid valve SLU, is output such that the predetermined pressure difference ΔPON required for lock-up on is obtained and therefore the pump impeller 20 and the turbine runner 24 are integrally rotated. The failure precondition during lock-up on control of the lock-up clutch 26 is a plurality of the failure preconditions, that is, a failure precondition group. Examples of the failure preconditions are as follows; the shift speed is the predetermined shift speed; the control pressure PSLU is higher than the predetermined hydraulic pressure, that is, the pressure difference ΔP is higher than the predetermined pressure difference ΔPON required for lock-up on; the throttle valve opening amount θTH is in the predetermined range; the vehicle speed V is in the predetermined range; and the absolute amount of the rotational speed difference NSLP is larger than predetermined rotational speed difference NSLP-P. The failure precondition state value obtaining means 104 obtains or detects the failure precondition state values required for determining whether the failure precondition group is satisfied. Example of the failure precondition state values are the present shift speed, the control pressure PSLU, the throttle valve opening amount θTH, the vehicle speed V, and the rotational speed difference NSLP.
The failure precondition satisfaction determining means 106 determines whether the present operation state is in the operation state where the predetermined failure precondition (the failure precondition group, when there is a plurality of the failure preconditions) for the control apparatus is satisfied. For example, when control is performed such that the lock-up clutch 26 is engaged, the failure precondition satisfaction determining means 106 determines whether the plurality of the failure preconditions, that is, the failure precondition group, is satisfied based on the failure precondition state values of the vehicle detected by the failure precondition state value obtaining means 104, such as the present shift speed, the control pressure PSLU, the throttle valve opening amount θTH, the vehicle speed V, the rotational speed difference NSLP. Example of the failure preconditions are as follows; the shift speed is the predetermined shift speed; the control pressure PSLU is higher than the predetermined hydraulic pressure; the throttle valve opening amount θTH is in the predetermined range; the vehicle speed V is in the predetermined range; and the absolute amount of the rotational speed difference NSLP is larger than predetermined rotational speed difference NSLP-P.
The failure precondition continuation quantity measuring means 108 measures the actual continuation quantity qNG of the operation state in which the failure precondition is continuously satisfied, when it is determined that the failure precondition is satisfied by the failure precondition satisfaction determining means 106. When it is determined that the failure precondition is not satisfied by the failure precondition satisfaction determining means 106, the continuation quantity qNG is regarded as “0”. For example, the actual continuation quantity qNG is the duration tNG of the operation state in which the predetermined failure precondition (the failure precondition group, when there is a plurality of the failure preconditions) is satisfied, or the number of times kNG that the operation state, in which the predetermined failure precondition (failure precondition group, there is a plurality of the failure preconditions) is satisfied, is realized.
The failure determining means 116 determines whether the continuation quantity qNG measured by the failure precondition continuation quantity measuring means 108 exceeds the prestored failure determination threshold value HSH, and sets a failure determination flag according to the result of the determination. For example, the failure determining means 116 sets the failure determination flag to 1″ when it is determined that the continuation quantity qNG exceeds the failure determination threshold value HSH, and sets the failure determination flag to “0”, until the time when the continuation quantity qNG exceeds the failure determination threshold value HSH. The failure precondition is satisfied not only when a failure has occurred in the control apparatus but also when the control apparatus is operating normally, depending on the contents of the failure precondition. For example, even when the drive duty ration DSLU is output such that the lock-up clutch 26 is engaged, the control apparatus is in the slip state, that is, in the operation state where the failure precondition is satisfied until the time when the lock-up clutch 26 is actually engaged, due to delay in response of the hydraulic pressure, or the like. If it is determined that a failure has occurred in the control apparatus simply because the failure precondition is satisfied, there is a possibility that an erroneous determination is made. Therefore, in order to avoid such an erroneous determination, the failure determination threshold value HSH is set such that a failure determination is not made based on the continuation quantity qNG of the failure precondition which is satisfied in the normal state, and further, such that it is promptly determined that a failure has occurred when a failure has actually occurred.
However, when the variation range is considerably large, the failure determination threshold value HSH is increased. Therefore, even when the duration tNG fluctuates largely due to a failure, there is a possibility that it is not determined a failure has occurred. For example, when the failure determination threshold value HSH is set to the value shown by the solid line A, in consideration of the entire variation ranges of the vehicle A and the vehicle B, even if the duration tNG largely fluctuates in the vehicle B due to a failure, there is a possibility that it is not determined a failure has occurred. On the other hand, when the failure determination threshold value HSH is decreased in order to improve the sensitivity of the failure determination, even if the duration tNG fluctuates in the normal state, there is a possibility that it is erroneously determined that a failure has occurred. For example, when the failure determination threshold value HSH is set to the value shown by the solid line B based on the variation range for the vehicle B, even if the duration tNG fluctuates in the vehicle A in the normal state, there is a possibility that it is erroneously determined that a failure has occurred. Therefore, a problem may occur that prevention of an erroneous determination regarding a failure and improvement in the sensitivity of the failure determination are incompatible with each other. Also, the failure determining means 116 need not make a determination when a failure determination cannot be made appropriately. For example, the failure determining means 116 need not make a determination, when there is an effect of another failure occurrence, e.g. when the ECU 90 determines that the turbine rotational speed NE is “0” due to a failure in the turbine rotational speed sensor 76 caused by braking of wire or the like and the slip amount NSLP (NE−NT) becomes considerably large. Also, the failure determining means 116 need not make a determination when the operating oil temperature of the lock-up clutch 26 largely deviates from the normal temperature, e.g., when the operating oil temperature is considerably low, e.g. near 0° C., or considerably high, e.g. near 140° C., and the operating characteristics of the lock-up clutch 26 are different from those in the normal state, for example. when the operating oil temperature is considerably low and delay in response occurs more frequently.
Therefore, in order to achieve both prevention of an erroneous determination regarding the failure and improvement in the sensitivity of the failure determination, the continuation quantity qNG of the failure precondition, which is satisfied even in the normal state, is stored, the failure determination threshold value HSH for each vehicle is decided based on the storage value, and a failure determination is made by the failure determining means 116. For example, in the vehicle A shown in
The smoothing means 112 is used as means for obtaining the variation range of the continuation quantity qNG. The smoothing means 112 smoothes the actual continuation quantity qNG of the operation state of the control apparatus, which is repeatedly measured by the failure precondition continuation quantity measuring means 108 each time when the predetermined failure precondition state is satisfied, and obtains the smooth processed value qNGAVG. The fluctuation in the continuation quantity qNG is smoothed in order to obtain the medium value of variation of the actual continuation quantity qNG. For example, as shown in
The storing means 110 stores the actual continuation quantity qNG which is measured by the failure precondition continuation quantity measuring means 108 each time when the operation state; in which the failure precondition is satisfied while the control apparatus is operating normally, is realized, or the smooth processed value qNGAVG obtained by smoothing the continuation quantity qNG by the smoothing means 112, as a storage value M. Namely, the storing means 110 stores the variation range of the continuation quantity qNG when the control apparatus is operating normally. Therefore, by storing the storage value M, it is possible to set the failure determination threshold value HSH for each vehicle in consideration of the individual differences such as variation between the vehicles. Therefore, it is not determined that a failure has occurred even when the operation state, in which the failure precondition is satisfied, is realized while the control apparatus is operating normally, and also it is promptly determined that a failure has occurred when a failure has actually occurred. As a result, it is possible to prevent the failure determining means 116 from making an erroneous determination regarding a failure in the control apparatus, thereby improving accuracy in detecting a failure.
The storage value M stored in the storing means 110 is used as a reference for setting the failure determination threshold value HSH, as mentioned above. If the variation range of the actual continuation quantity qNG can be obtained, it is possible to set the failure determination threshold value HSH for preventing an erroneous determination regarding a failure. In this case, the variation range of the actual continuation quantity qNG is the variation range when the operation state, in which the failure precondition is satisfied, is realized. Accordingly, the storing means 110 may select the value which shows the variation range of the actual continuation quantity qNG from the actual continuation quantity qNG which is repeatedly measured or the smooth processed value qNGAVG of the actual continuation quantity qNG, and may set the selected value as the storage value M. Hereafter, examples of the methods for storing the storage value M will be described based on the duration tNG or the smooth processed time TNGAVG in
For example, in order to obtain the upper limit of the variation range, the selection time tSH, which is set to a value approximately half of the failure determination threshold value HSH, may be set as a predetermined time, and only the duration tNG or the smooth processed time tNGAVG which exceeds the selection time tSH may be stored as the storage values M. For example, only the duration tNG7 and tNG9, or only the smooth processed time tNF7-8 may be stored as the storage values M, in the case in
The storing means 110 need not perform storage when a failure determination cannot be made appropriately. For example, the storing means 110 need not perform storage, when there is an effect of another failure occurrence, e.g. when the slip amount NSLP (=NE−NT) becomes considerably large due to a failure in the turbine rotational speed sensor 76 caused by braking of wire, or the like. Also, the storing means 110 need not perform storage when the operation of the control apparatus is unstable, e.g., when the operating oil temperature is considerably low and delay in response occurs more frequently. Also, since the storage value M is not required when the failure determination is not performed, the above-mentioned storage need not be performed. Thus, it is possible to reduce the amount of unnecessary writing to the memory, thereby reducing the number of the storage values M. However, the condition in which the failure precondition tends to be satisfied may be obtained by the storage value MN when the failure determination is not performed by the failure determining means 116. Therefore, the storage value M when the failure determination is performed by the failure determining means 116, and the storage value MN when the failure determination is not performed by the failure determining means 116 may be distinguished and then stored.
The failure determination threshold value correcting means 114 sets or corrects the failure determination threshold value HSH based on the actual continuation quantity qNG when the operation state, in which the failure precondition is satisfied while the control apparatus is operating normally, is realized; the smooth processed value qNGAVG of the actual continuation quantity qNG; or the storage value M. For example, the new failure determination threshold value HSH is set by increasing the value of the storage value M, e.g. the average value of the storage values M, at a predetermined rate or adding a predetermined value to the storage value M, or the failure determination threshold value HSH is changed at a predetermined increase/decrease rate or using the increase/decrease value corresponding to the storage value M, whereby the failure determination threshold value HSH is corrected by learning. Thus, the failure determination threshold value HSH is set or corrected to a value based on the characteristics of each vehicle by the failure determination threshold value correcting means 114. Therefore, it is possible to prevent the failure determining means 166 from making an erroneous determination regarding a failure when the failure precondition is satisfied while the control apparatus is operating normally. It is also possible to improve the sensitivity of the failure determination.
The failure determination threshold value correcting means 114 need not perform the correction when the failure determination is not performed by the failure determining means 116. Also, when the failure determination is not performed by the failure determining means 116, the failure determination threshold value correcting means 114 need not perform the correction, since the failure determination threshold value HSH is not required. Also, the failure determination threshold value correcting means 114 need not perform the correction based on the storage value MN stored in the storing means 110 when the failure determination is not performed. Thus, it is possible to set the accurate failure determination threshold value HSH.
When a negative determination is made in SA2, in SA6 corresponding to the failure precondition continuation quantity measuring means 108, the actual continuation quantity qNG, which is the measurement value in the operation state in which the failure precondition is continuously satisfied, is made “0”, afterwhich the routine ends. An example of the actual continuation quantity qNG is the continuation quantity qNG when the lock-up clutch 26 is engaged, e.g. the duration tNG. On the other hand, when an affirmative determination is made in SA2, in SA3 corresponding to the failure precondition continuation quantity measuring means 108, the actual continuation quantity qNG, which is the measurement value in the operation state in which the failure precondition, is continuously satisfied is measured. An example of the actual continuation quantity qNG is the continuation quantity qNG when the lock-up clutch 26 is engaged, e.g. the duration tNG. In SA4 corresponding to the storing means 110, the duration tNG of the operation state, in which the failure precondition is satisfied when the control apparatus is operating normally, is stored as the storage value M. Also, in SA4, the smooth processed time tNGAVG of the duration tNG, which is obtained through smooth process performed by the smoothing means 112, may be stored as the storage value M. The value, which is selected from the duration tNG or the smooth processed time tNGAVG such that the variation range of the duration tNG can be obtained, may be stored as the storage value M. For example, the number of times NSH, that the duration tNG or the smooth processed time tNGAVG exceeds the selection time tSH which is set to a value approximately half of the failure determination threshold value HSH, may be set as the storage value M. The duration tNG or the smooth processed time tNGAVG which exceeds the selection time tSH may be set as the storage value M. Also, the maximal value obtained by successively updating the largest value of the duration tNG or the smooth processed time tNGAVG may be stored as the storage value M.
In SA5 corresponding to the failure determination threshold value correcting means 114, the failure determination threshold value HSH is corrected based on the storage value M in the operation state in which the failure precondition is satisfied when the control apparatus is operating normally. For example, the new failure determination threshold value HSH is set by increasing the average value of the storage values M at a predetermined rate or by adding a predetermined value to the storage value M, or the failure determination threshold value HSH is changed at a predetermined increase/decrease rate or using the increase/decrease value corresponding to the storage value M, whereby the failure determination threshold value HSH is corrected. As a result, the failure determination threshold value HSH is set or corrected to the failure determination threshold value HSH based on the characteristics of each vehicle according to the storage value M of the duration tNG of the operation state in which the failure precondition group is continuously satisfied when the control apparatus is operating normally is satisfied. Correction of the preset failure determination threshold value HSH may be performed automatically by learning, as mentioned above, or may be performed through operation at a plant, a maintenance shop of a dealer, or the like. For example, the vehicle is made to run on a test course or on a chassis dynamo, at the time of factory shipment, in the plant, the maintenance shop of the dealer or the like. Then, the actual continuation quantity qNG of the operation state, in which the failure precondition is continuously satisfied when the control apparatus is operating normally, is detected by a test tool, a test equipment or the like, and the detected value is stored as the storage value M. Also, the failure determination threshold value HSH may be calculated or corrected based on the storage value M, according to an operation manual or the like. Also, calculation or correction of the failure determination threshold value HSH based on the storage value M may be performed automatically by the check tool, the check equipment or the like.
Also, when a failure determination in SB4 in
As described so far, according to the embodiment, the failure determination threshold value HSH, which is used for determining whether a failure has occurred in the control apparatus, e.g. the lock-up clutch 26 by the failure determining means 116 (SB4), is corrected by the failure determination threshold value correcting means 114 (SA5) based on the continuation quantity qNG of the operation state, in which the predetermined failure precondition for the control apparatus provided in the vehicle is satisfied, for example, the duration tNG. Therefore, a failure determination is performed by the failure determining means 116 using the failure determination threshold value HSH obtained in consideration of individual differences such as the variations between vehicles. As a result, it is possible to prevent an erroneous determination regarding the failure, and to improve the sensitivity of the failure determination.
Also, according to the invention, correction by the failure determination threshold value correcting means 114 (SA5) is performed based on the continuation quantity qNG of the operation state when the control apparatus is operating normally and when the continuation quantity qNG is smaller than the failure determination threshold value HSH. Thus, the failure determination threshold value HSH is appropriately corrected by the failure determination threshold value correcting means 114. As a result, it is possible to prevent the failure determining means 116 from making an erroneous determination regarding a failure (SB4), and to improve the sensitivity of the failure determination.
Also, according to the embodiment, the storing means 110 (SA4) for storing the actual continuation quantity qNG is provided, and the failure determination threshold value correcting means 114 (SA5) corrects the failure determination threshold value HSH based on a storage value M stored in the storing means 110. Thus, correction of the failure determination threshold value HSH is appropriately performed by the failure determination threshold value correcting means 114 based on the actual continuation quantity qNG.
Also, according to the embodiment, the storing means 100 (SA4) stores the smooth processed value qNGAVG of the actual continuation quantity qNG of the operation state of the control apparatus, which is obtained by the smoothing means 112 (SA4), each time when the predetermined failure precondition is satisfied. The continuation quantity qNG is repeatedly detected by the continuation quantity detecting means 102 (SA1 to SA3, SBA to SB3). Therefore, correction of the failure determination threshold value HSH is appropriately performed by the failure determination threshold value correcting means 114 (SA5), based on the smooth processed value qNGAVG which is obtained, using the smoothing means 112, by smoothing the fluctuation in the actual continuation quantity qNG of the operation state, the fluctuation being due to causes other than the individual differences such as the variation of the vehicles, for example, the fluctuation being due to the driving operation or the running condition.
Also, according to the embodiment, the continuation quantity qNG is the duration tNG of the operation state in which the predetermined failure precondition is satisfied, and the storing means 100 (SA4) stores the number of times that the actual continuation quantity qNG or the smooth processed value qNGAVG exceeds the predetermined time. Therefore, since the number of times that the actual continuation quantity qNG or the smooth processed value qNGAVG exceeds the predetermined time is stored in the storing means 110, it is possible to reduce the amount of information to be stored in the storing means 110, thereby preventing garbling of the storage value and/or deterioration of the durability of the storing means 110.
Also, according to the embodiment, the continuation quantity qNG is the duration tNG of the operation state in which the predetermined failure precondition is satisfied, and the storing means 110 (SA4) stores the actual continuation quantity qNG or the smooth processed value qNGAVG which exceeds the predetermined time. Therefore, since only the actual continuation quantity qNG or the smooth processed value qNGAVG which exceeds the predetermined time is stored in the storing means 110, it is possible to reduce the amount of information to be stored in the storing means 110, thereby preventing garbling of the storage value and/or deterioration of the durability of the storing means 110.
Also, according to the embodiment, the storing means 110 (SA4) stores the maximal value of the actual continuation quantity qNG or the maximal value of the smooth processed value qNGAVG. Therefore, since the storing means 110 stores only the maximal value of the actual continuation quantity qNG or the maximal value of the smooth processed value qNGAVG, it is possible to reduce the amount of information to be stored in the storing means 110, thereby preventing garbling of the storage value and/or deterioration of the durability of the storing means 110.
Also, according to the embodiment, the failure determination threshold value correcting means 114 (SA5) does not correct the failure determination threshold value HSH when a failure determination for the control apparatus is not performed by the failure determining means 116 (SB4). Therefore, the failure determination threshold value HSH is corrected by the failure determination threshold value correcting means 114 only when a failure determination is performed. As a result, it is possible to appropriately determine whether a failure has occurred.
Also, according to the embodiment, the storing means 110 (SA4) does not store the actual continuation quantity qNG or the smooth processed value qNGAVG when a failure determination for the control apparatus, e.g. the lock-up clutch 26 is not performed by the failure determining means 116 (SB4). Therefore, the actual continuation quantity qNG or the smooth processed value qNGAVG stored in the storing means 110 does not include the actual continuation quantity qNG or the smooth processed value qNGAVG when a failure determination is not performed. Therefore, it is possible to appropriately correct the failure determination threshold value using the failure determination threshold value correcting means 114 (SA5), and to appropriately determine whether a failure has occurred.
Also, according to the embodiment, since the control apparatus is the power transmission system which transmits power from the engine to the drive wheels, it is possible to appropriately determine whether a failure has occurred in the power transmission system. For example, it is appropriately determined whether a failure has occurred in the linear solenoid valve SLU which controls the hydraulic pressure of the lock-up clutch 26 provided in the torque converter 14 as the power transmission system.
While the embodiment of the invention has been described in detail with reference to accompanying drawings, the invention can be realized in other embodiments.
For example, in the above-mentioned embodiment, the power transmission system as the control apparatus may be the automatic transmission 16, a front/rear wheel power distribution device with a power distribution clutch, or the like which distributes the engine output that is transmitted via the automatic transmission 16 to the drive wheels. For example, in the case of the automatic transmission 16, it is appropriately determined whether there a failure has occurred in the solenoid valves Sol1 to Sol5, the linear solenoid valves SL1 and SL2, and the like.
Also, in the above-mentioned embodiment, the failure determination threshold value correcting operation and the failure determination operation are performed according to different flowcharts, as shown in
Also, according to the above-mentioned embodiment, the torque converter 14 provided with the lock-up clutch 26 is used as the fluid transmission device. However, a fluid coupling, which does not have torque amplification action, may be used.
Also, in the above-mentioned embodiment, the automatic transmission 16 is a six forward speed transmission including three planetary gear drives 40, 42 and 44. However, any types of transmission may be employed as long as the hydraulic friction engaging devices such as clutches C or the brakes C are engaged for engine brake effect. The number of the planetary gear drives constituting the automatic transmission 16 may be different from three. Also, the transmission with five forward speeds, or four forward speeds may be employed. Also, the automatic transmission 16 may be constituted of a shift portion formed of the hydraulic friction engaging devices such as clutches and brakes, or the one-way clutch, for example, forward/rearward switching or two forward speed transmission, and the continuously variable transmission in which the gear ratio is continuously changed.
Also, in the above-mentioned embodiment, the clutches C or the brakes B, which are the engaging elements of the automatic transmission 16, are hydraulic friction engaging devices. However, electromagnetic engaging devices such as electromagnetic clutches and the magnetic particle clutches may be employed.
While the invention has been described in detail with reference to the preferred embodiments, it will be apparent to those skilled in the art that the invention is not limited to the above-mentioned embodiments, and that the invention may be realized in various other embodiments within the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-117391 | Apr 2003 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB04/01200 | 4/21/2004 | WO | 8/9/2005 |
