JP6146003B2 - Clutch state determination device and vehicle mass estimation device - Google Patents

Description

  The present invention relates to a clutch state determination device that determines whether or not a clutch disposed in a torque transmission path from a driving source such as an engine to a wheel is in a disconnected state, and a vehicle mass estimation device including the clutch state determination device.

  Some vehicles such as trucks and buses have a vehicle mass estimation device that calculates an estimated value of the vehicle mass when the vehicle travels because the vehicle mass greatly fluctuates with an increase or decrease in the load capacity or the number of passengers. For example, in the vehicle mass estimation device described in Patent Document 1, the difference in driving force between the case where the clutch is in the connected state and the case where the clutch is in the disconnected state is shown. By dividing the vehicle acceleration difference between a certain case and the vehicle acceleration, an estimated value of the vehicle mass can be obtained.

  By the way, in order to calculate the estimated value of the vehicle mass as described above, it is necessary to determine whether or not the clutch is disengaged. Patent Document 2 discloses an example of an apparatus that determines a clutch state without using a detection signal from a sensor for directly detecting the clutch state. That is, in such a device, the transmission gear ratio is calculated by dividing the engine rotational speed by the wheel rotational speed, which is the rotational speed of the driving wheel of the vehicle, and the speed change that is the amount of change per unit time of the transmission ratio. A ratio change amount is calculated. When the speed ratio change amount is less than a predetermined determination value, it is determined that the clutch is in a connected state, and when the speed ratio change amount is greater than or equal to a determination value, it is determined that the clutch is in a disconnected state. It has become.

Japanese Patent Laid-Open No. 2002-13620 JP 2009-236220 A

  Here, when the clutch shifts from the connected state to the disconnected state, it is preferable to quickly detect the change in this state. As a method for enabling early determination of the clutch being in a disengaged state in this way, there is a method of setting the determination value as small as possible.

  However, the engine rotation speed and the wheel rotation speed are sensor values based on signals output from the crank angle sensor and the wheel speed sensor, and such sensor values are detected with some detection error. For this reason, the speed ratio and the amount of change in the speed ratio change to some extent due to detection errors included in the engine speed and the wheel speed. As a result, when the determination value is set to a small value, even if the clutch is in the engaged state, the change in the gear ratio becomes greater than or equal to the determination value due to the detection error, and it is erroneously determined that the clutch is in the disconnected state. There is a risk of being.

  The present invention has been made in view of such circumstances. An object of the present invention is to provide a clutch state determination device and a vehicle mass estimation device that can improve the determination accuracy of whether or not the clutch is disengaged.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A clutch state determination device that solves the above-described problem is a transmission gear ratio and a change of the gear ratio with respect to time according to an engine speed detected by an engine speed sensor and a wheel speed detected by a wheel speed sensor. A calculation unit that calculates a speed ratio change amount that is an amount, a determination unit that determines that the clutch is disengaged when the calculated absolute value of the speed ratio change amount is equal to or greater than a determination value, And a setting unit that sets a larger value than when the wheel speed is large.

  The engine speed is a sensor value detected based on a signal output from the engine speed sensor, and the wheel speed is a sensor value detected based on a signal output from the wheel speed sensor. Such sensor values are detected with some error. Therefore, the transmission gear ratio and the speed ratio change amount calculated according to the engine speed and the wheel speed vary due to the influence of errors included in the engine speed and the wheel speed.

  A transmission provided in the vehicle has a plurality of shift stages. Therefore, even if the engine speed is a certain number of revolutions, the wheel speed of the wheels, that is, the number of revolutions of the wheels will be different if the selected gear stage is different. At this time, when the shift speed is the low speed shift speed, the speed of the wheel is smaller than when the shift speed is the high speed shift speed. The amount of error included in the amount of change increases.

  Therefore, in the above configuration, the determination value, which is a criterion for determining whether or not the clutch is in the disengaged state, is set to a larger value when the wheel speed is low when the vehicle is traveling than when the wheel speed is high. For this reason, when the low speed side gear stage is selected as the speed stage, the gear ratio change amount fluctuates relatively greatly due to an error included in the sensor value detected by each sensor. The absolute value of the gear ratio change amount is less likely to be greater than or equal to the determination value. Therefore, when the clutch is in a connected state, the possibility that the clutch is erroneously determined to be in a disconnected state is reduced. Therefore, it is possible to improve the accuracy of determining whether or not the clutch is in a disengaged state.

  The clutch state determination device may further include a gear position specifying unit that specifies the gear position of the selected transmission based on the gear ratio calculated by the calculation unit. In this case, when the shift stage of the transmission specified by the shift stage specifying unit is changed to the high speed side shift stage, the setting unit sets the determination value to a value smaller than that before the specified shift stage is changed. When the shift stage of the transmission that is set and specified by the shift stage specifying unit is changed to the low-speed side, it is preferable to set the determination value to a value that is larger than that before the specified shift stage is changed.

  In the above configuration, the currently selected gear stage is specified based on the calculated gear ratio. When the specified shift speed is changed to a high speed shift speed, the determination value becomes smaller than the previous value. On the other hand, when the specified shift speed is changed to the low speed shift speed, the determination value becomes larger than the previous value. In other words, the determination value is a larger value when the identified shift speed is the low speed shift speed than when the identified shift speed is the high speed shift speed. Therefore, even when the clutch is in the engaged state, the absolute value of the change ratio of the gear ratio is less likely to be equal to or greater than the determination value at that time when the vehicle travels at a low speed where the change ratio of the speed ratio varies relatively greatly. As a result, it is possible to reduce the possibility of erroneous determination that the clutch is in the disconnected state when the clutch is in the connected state.

  On the other hand, when the vehicle whose speed ratio change amount does not fluctuate so much is high speed, the specified shift speed becomes the high speed shift speed, so that the determination value is set to a smaller value compared to low speed travel. Become so. Therefore, when the clutch shifts from the connected state to the disconnected state, it can be determined early that the clutch is in the disconnected state.

  Alternatively, a determination candidate value may be prepared in advance for each wheel speed region, and the determination candidate value may be set to a smaller value as the wheel speed increases. The clutch state determination device may further include a region specifying unit that specifies in which region the wheel speed is included. In this case, the setting unit preferably sets the determination value to a determination candidate value corresponding to the region specified by the region specifying unit.

  In the above configuration, the region in which the wheel speed is included is specified, and the determination value is set according to the determination candidate value corresponding to the specified region. That is, in the process of increasing the wheel speed, if the area including the wheel speed shifts to the high speed area, the determination value becomes smaller than before. In other words, the determination value is larger when the region including the wheel speed is the low speed region than when the region is the high speed region. For this reason, even when the clutch is in the engaged state, the absolute value of the change ratio of the gear ratio is less likely to be equal to or higher than the determination value at that time when the vehicle travels at a low speed where the change ratio of the speed ratio varies relatively greatly. As a result, it is possible to reduce the possibility of erroneous determination that the clutch is in the disconnected state when the clutch is in the connected state.

  On the other hand, the determination value is set to a smaller value when the vehicle where the change ratio of the gear ratio does not fluctuate significantly is high speed than when the vehicle is low speed. Therefore, when the clutch shifts from the connected state to the disconnected state, it can be determined early that the clutch is in the disconnected state.

  Further, the vehicle mass estimation device is configured such that the difference between the driving force transmitted to the wheel when the clutch is in a disconnected state and the driving force transmitted to the wheel when the clutch is in a connected state, A mass calculation unit that calculates an estimated value of the vehicle mass according to a difference between the acceleration of the vehicle at a certain time and the acceleration of the vehicle when the clutch is in a connected state, and the clutch state determination device described above. I prepared.

  According to the above configuration, it is possible to improve the calculation accuracy of the estimated value of the vehicle mass as much as it is possible to accurately determine whether or not the clutch is in the disengaged state.

Schematic which shows the vehicle by which ECU for brakes which is one Embodiment of the state determination apparatus of a clutch is mounted. A map for setting a judgment value according to wheel speed and gear position. The flowchart explaining the process routine which ECU for brakes performs in order to perform the state determination of a clutch, and the estimation calculation of vehicle mass. (A)-(g) is a timing chart which shows an example of the timing which acquires a driving force and acceleration at the time of vehicle travel. The map for setting a judgment value in another embodiment. The map for setting a judgment value in other another embodiment.

Hereinafter, an embodiment of a vehicle in which a brake ECU functions as a clutch state determination device will be described with reference to the drawings.
As shown in FIG. 1, the vehicle includes a power transmission mechanism 12 that transmits driving force generated by the engine 11 to a plurality of (for example, four) wheels 10, and a braking device 20 that applies braking force to the wheels 10. Is provided. The power transmission mechanism 12 includes a clutch 121, a transmission 122, and a differential gear 123 that are disposed along the power transmission path. The clutch 121 operates to permit or prohibit power transmission by the operation of a clutch pedal (not shown) by the driver. The transmission 122 is a stepped (for example, forward three-speed) transmission, and is set to a gear position according to an operation mode of a shift lever (not shown) by the driver.

  The engine 11 is controlled by an engine ECU 14 (also referred to as “engine electronic control device”). The engine ECU 14 detects an operation amount of the accelerator pedal 13, that is, an accelerator opening sensor SE1 for detecting the accelerator opening, and an engine speed NE that is the rotation speed of the crankshaft 124 of the engine 11. The crank angle sensor SE2 is electrically connected. The engine ECU 14 is electrically connected to a rotation speed detection sensor SE3 for detecting the rotation speed of the output shaft 125 of the transmission 122. In the present embodiment, the crank angle sensor SE2 functions as an example of an engine speed sensor.

  Then, the engine ECU 14 calculates the accelerator opening based on the detection signal from the accelerator opening sensor SE1, and controls the engine 11 based on the calculated accelerator opening. Further, the engine ECU 14 calculates the rotational speed of the output shaft 125 of the transmission 122 based on the detection signal from the rotational speed detection sensor SE3, and calculates the driving force F transmitted to the wheels 10 based on the calculated rotational speed. To do.

  The braking device 20 includes a hydraulic pressure generating device 23 and a brake actuator 24. When the driver operates the brake pedal 21, the hydraulic pressure in the master cylinder constituting the hydraulic pressure generator 23 increases, and the amount of brake fluid corresponding to the hydraulic pressure is not shown in the drawing of the brake actuator 24. It flows into a wheel cylinder 25 provided for each wheel 10 through a circuit. As a result, a braking force corresponding to the hydraulic pressure in the corresponding wheel cylinder 25 is applied to the wheel 10.

  The brake actuator 24 is controlled by a brake ECU 30 (also referred to as “brake electronic control device”). The brake ECU 30 includes a brake switch SW1 for detecting whether or not the driver has operated the brake pedal 21, a wheel speed sensor SE4 for detecting the wheel speed VW of the wheel 10, and a longitudinal acceleration of the vehicle. A longitudinal acceleration sensor SE5 for detecting (vehicle acceleration) is electrically connected. Further, the brake ECU 30 can receive information about the driving force F and the engine speed NE from the engine ECU 14 via the bus 40. The brake ECU 30 appropriately controls the brake actuator 24 based on information detected by various switches and sensors, information received from the engine ECU 14, and the like.

  By the way, the brake ECU 30 of the present embodiment calculates an estimated value M of the vehicle mass based on the acceleration A detected by the longitudinal acceleration sensor SE5 and the driving force F calculated by the engine ECU 14. That is, the brake ECU 30 acquires the acceleration A1 (A) and the driving force F1 (F) when the clutch 121 is in a disconnected state, that is, when the driving force from the engine 11 is not transmitted to the wheel 10. In addition, after acquiring the acceleration A1 and the driving force F1, the brake ECU 30 determines the acceleration A2 (A) and the acceleration A2 (A) when the clutch 121 is in a connected state, that is, when the driving force from the engine 11 is transmitted to the wheel 10. The driving force F2 (F) is acquired.

  And brake ECU30 calculates the estimated value M of vehicle mass using the relational expression (Formula 1) shown below. Here, the estimated value M of the vehicle mass is calculated using a known equation of motion “F = M × A”. In this regard, in the present embodiment, the brake ECU 30 functions as a “vehicle mass estimation device”. In the present embodiment, the “vehicle mass” is a concept including at least a mass of the vehicle itself, a mass of cargo loaded on the vehicle, and a mass based on a passenger on the vehicle.

M = (F2-F1) / (A2-A1) (Formula 1)
Further, the brake ECU 30 of the present embodiment determines the current speed ratio TR and the speed ratio TR according to the engine speed NE detected by the crank angle sensor SE2 and the wheel speed VW detected by the wheel speed sensor SE4. A gear ratio change amount ΔTR, which is a change amount per unit time, is calculated. Then, the brake ECU 30 determines whether or not the clutch 121 is in a disengaged state using the calculated gear ratio change amount ΔTR. Therefore, in the present embodiment, the brake ECU 30 also functions as a “clutch state determination device”.

  The gear ratio TR can be calculated using the following relational expressions (Expression 2) and (Expression 3). The engine rotational speed NE and the wheel rotational speed NW are the rotational speed per minute (rpm), the wheel speed VW is the travel distance per hour (km / hour), and the wheel diameter D is outside the wheel 10. It is a diameter dimension (m).

Gear ratio TR = (engine speed NE) / (wheel speed NW) (Formula 2)
Wheel rotation speed NW = (1000 · wheel speed VW) / (60 · π · wheel diameter D) (Formula 3)
Further, the determination of whether or not the clutch 121 is disengaged, that is, the state determination of the clutch 121 is performed by comparing the speed ratio change amount ΔTR and the determination value ΔTR_th. Specifically, when the gear stage of the transmission 122 is not changed, the clutch pedal and the shift lever are not operated by the driver, and therefore the speed ratio TR calculated using the relational expression (Formula 1) is substantially constant. Become. Therefore, the absolute value | ΔTR | of the speed ratio change amount, which is the change amount per unit time of the speed ratio TR, is not so large.

  On the other hand, when the shift stage of the transmission 122 is changed from the low speed side to the high speed side, the clutch 121 is disengaged by the operation of the clutch pedal by the driver, and this state is maintained. In addition, the gear position is changed by the driver operating the shift lever. In such a case, generally, the amount of depression of the accelerator pedal 13 by the driver is reduced. For this reason, the wheel speed VW of the wheel 10 to which the driving force has been transmitted from the engine 11 is substantially maintained, while the engine speed NE decreases. As a result, the speed ratio TR calculated using the relational expression (formula 1) gradually decreases as the engine speed NE decreases, and the speed ratio change amount ΔTR, which is the gradient, greatly decreases. Therefore, by setting the determination value ΔTR_th to an appropriate value, it is determined whether or not the clutch 121 is in the disengaged state depending on whether or not the absolute value | ΔTR | of the gear ratio change amount is equal to or greater than the determination value ΔTR_th. It becomes possible.

  Further, when the speed of the transmission 122 is changed from the high speed side to the low speed side in order to decelerate the vehicle, the driver is not operating the accelerator pedal 13 or is operating it. However, the clutch 121 is disengaged by the operation of the clutch pedal by the driver while the operation amount is very small. Therefore, while the wheel speed VW of the wheel 10 to which the driving force has been transmitted from the engine 11 is substantially maintained, the load on the engine 11 is reduced by the disengagement of the clutch 121, so the engine speed NE increases. As a result, the speed ratio TR calculated using the relational expression (formula 1) gradually increases as the engine speed NE increases. Therefore, even when the gear position of the transmission 122 is changed from the high speed gear position to the low speed gear position, the absolute value of the gear ratio change amount can be obtained by setting the determination value ΔTR_th to an appropriate value. Whether or not the clutch 121 is in the disengaged state can be determined based on whether or not | ΔTR | is equal to or greater than the determination value ΔTR_th.

  Here, the engine speed NE and the wheel speed VW are sensor values based on signals output from the crank angle sensor SE2 and the wheel speed sensor SE4. In general, the detection error included in the wheel speed VW detected by the wheel speed sensor SE4 is larger than the detection error included in the engine speed NE detected by the crank angle sensor SE2. For example, the engine speed NE is detected with a detection error of about ± 3%, while the wheel speed VW is detected with a detection error of about ± 5%. As a result, the speed ratio TR and the speed ratio change amount ΔTR calculated using the relational expressions (Expression 2) and (Expression 3) are affected by the detection error included in the engine speed NE and the wheel speed VW. Will vary.

  Further, in the vehicle of the present embodiment, even if the engine speed NE is an engine speed (for example, 2000), the selected shift speed is the low speed (for example, the first speed shift). The wheel speed VW is smaller than the wheel speed VW when the selected gear is a high-speed gear (for example, the second gear). Under the condition that the engine speed NE is constant, when the wheel speed VW is small, the variation in the calculated speed ratio TR becomes larger than when the wheel speed VW is large. Here, “the wheel speed VW is high” indicates that the wheel speed VW is high, and “the wheel speed VW is low” indicates that the wheel speed VW is low.

  As an example, the engine speed NE is “1100”, the true speed ratio TR_T of the low speed side gear stage is “100”, and the true speed ratio TR_T of the high speed side speed stage is “11”. To do. The wheel speed VW detected by the wheel speed sensor SE4, that is, the error rate of the wheel rotational speed NW is assumed to be “± 10%”. “True gear ratio TR_T” is a design value set in advance for each gear position.

  In this case, assuming that the selected gear position is the low speed gear position, the gear ratio TR calculated using the above equation (Equation 2) is “90.9” to “111.1”. Will fluctuate between. That is, the fluctuation range obtained by subtracting the minimum value from the maximum value is about “20.2 (= 111.1-90.9)”. On the other hand, assuming that the selected gear position is the high speed gear position, the calculated gear ratio TR varies between “10” and “12.22”. That is, the fluctuation range obtained by subtracting the minimum value from the maximum value is approximately “2.22 (= 12.22-10)”.

  Therefore, when the wheel speed VW is low, such as when the low speed side gear is selected, the determination value ΔTR_th is set to a relatively large value, and the clutch 121 is in the disconnected state even though the clutch 121 is in the connected state. It is preferable to make it difficult to make a false determination. On the other hand, the determination value ΔTR_th is set to a relatively small value when the wheel speed VW is high, such as when the high speed side gear is selected, so that the disengagement state of the clutch 121 can be detected early. Is preferred. Therefore, in the present embodiment, the determination value ΔTR_th is set to a value corresponding to the selected shift speed and wheel speed VW.

Next, a map for setting the determination value ΔTR_th will be described with reference to FIG.
The map shown in FIG. 2 shows the relationship between each shift speed of the transmission 122 and the determination candidate value CV (CVG1, CVG2, CVG3) for each shift speed. That is, the first determination candidate value CVG1 corresponding to the first speed shift stage that is the lowest speed shift stage corresponds to the second speed and third speed shift stages that are higher speed shift stages. This value is larger than the second and third determination candidate values CVG2 and CVG3. Further, the third determination candidate value CVG3 corresponding to the third shift speed, which is the highest speed shift speed, corresponds to the first speed and second speed shift speeds, which are lower speed shift speeds. The value is smaller than each of the first and second determination candidate values CVG1 and CVG2. Moreover, the determination candidate value CV becomes smaller as the wheel speed VW is larger at the same shift speed.

  In the present embodiment, the wheel speed range that can be selected for each gear position of the transmission 122 is different. Specifically, the upper limit values VW1_max, VW2_max, and VW3_max of the wheel speed regions corresponding to the respective shift speeds indicate the allowable maximum speed of the engine 11 mounted on the vehicle by the true speed ratio TR_T of the corresponding shift speed. The wheel speed corresponds to a value obtained by dividing or a value slightly larger than this value. On the other hand, the lower limit value VW1_min of the wheel speed region corresponding to the first gear is “0 (zero)”, and the lower limit of the wheel speed region corresponding to the second and third gears. The values VW2_min and VW3_min are wheel speeds corresponding to a value obtained by dividing the idling speed of the engine 11 by the true gear ratio TR_T of the corresponding gear stage or a value slightly smaller than this value. The “idling speed” is the engine speed NE when the operation amount of the accelerator pedal 13 is “0 (zero)” or a value corresponding thereto.

  Next, a processing routine executed by the brake ECU 30 to determine the state of the clutch 121 and calculate the estimated value M of the vehicle mass will be described with reference to the flowchart shown in FIG. This processing routine is a processing routine that is executed every predetermined cycle set in advance.

  As shown in FIG. 3, in the present processing routine, the brake ECU 30 acquires the engine speed NE and the wheel speed VW detected by the crank angle sensor SE2 and the wheel speed sensor SE4 (step S11). Then, the brake ECU 30 calculates the current speed ratio TR of the transmission 122 by substituting the engine speed NE and the wheel speed VW acquired in step S11 into the relational expressions (Expression 2) and (Expression 3). (Step S12). Subsequently, the brake ECU 30 corresponds to a difference obtained by subtracting the speed ratio TR (n−1) as the calculation result in the previous cycle from the speed ratio TR (n) as the calculation result in the current cycle. The gear ratio change amount ΔTR is obtained by dividing by the time required (step S13). In this respect, in the present embodiment, the brake ECU 30 also functions as an “arithmetic unit” that calculates the gear ratio TR and the gear ratio change amount ΔTR of the transmission 122 according to the engine speed NE and the wheel speed VW. .

  Subsequently, the brake ECU 30 specifies the gear stage of the transmission 122 currently selected based on the gear ratio TR calculated in step S12 (step S14). In this regard, in the present embodiment, the brake ECU 30 also functions as a “speed stage specifying unit” that specifies the speed stage of the selected transmission 122 based on the calculated speed ratio TR.

  Here, an example of a method for specifying the gear position will be described. In the brake ECU 30, a gear ratio region including the true gear ratio TR_T is prepared in advance for each gear position. For example, when the calculated gear ratio TR is included in the gear ratio region of the first gear, the brake ECU 30 specifies that the selected gear is the first gear. When the calculated gear ratio TR is not included in any gear ratio region, the brake ECU 30 sets the selected gear to a gear having a gear ratio region higher than the calculated gear ratio TR. And For example, when the calculated shift speed is less than the lower limit value of the speed ratio area of the first speed gear stage and higher than the upper limit value of the speed change area of the second speed gear stage, the brake ECU 30 is selected. The existing gear is the first gear.

  Then, the brake ECU 30 refers to the map shown in FIG. 2 and sets the determination value ΔTR_th to a value corresponding to the wheel speed VW acquired in step S11 and the gear position specified in step S14 (step S15). Specifically, the brake ECU 30 selects a determination candidate value CV (CVG2) corresponding to the specified shift speed (for example, the second speed shift speed), and further selects the determination candidate value CV (CVG2). A value corresponding to the wheel speed VW is selected, and this value is set as a determination value ΔTR_th. In this regard, in this embodiment, the brake ECU 30 also functions as a “setting unit” that sets the determination value ΔTR_th to a larger value when the wheel speed VW is smaller than when the wheel speed VW is large.

  Subsequently, the brake ECU 30 determines whether or not the absolute value | ΔTR | of the speed ratio change amount calculated in step S13 is greater than or equal to the determination value ΔTR_th set in step S15 (step S16). In this regard, in the present embodiment, the brake ECU 30 also functions as a “determination unit” that determines that the clutch 121 is disengaged when the absolute value | ΔTR | of the gear ratio change amount is equal to or greater than the determination value ΔTR_th. . When the absolute value | ΔTR | of the gear ratio change amount is equal to or greater than the determination value ΔTR_th (step S16: YES), the brake ECU 30 sets “1” to the flag FLG because it can be determined that the clutch 121 is disengaged. (Step S17). This flag FLG is a flag used to determine whether or not the clutch 121 is in a disconnected state, and is set to “1” when it is determined that the clutch 121 is in a disconnected state.

  Subsequently, the brake ECU 30 resets the counter value Cnt to “0 (zero)” (step S18). Then, the brake ECU 30 obtains the driving force F currently transmitted to the wheel 10 and the current acceleration A of the vehicle as the driving force F1 and acceleration A1 when the clutch 121 is in the disengaged state (step S19). Then, the process proceeds to step S23 described later.

  On the other hand, when the absolute value | ΔTR | of the gear ratio change amount is less than the determination value ΔTR_th in the previous step S16 (step 16: NO), the brake ECU 30 sets the counter reference value Cnt_th to which the counter value Cnt is set in advance. It is determined whether this is the case (step S20).

  Elapsed time after the absolute value | ΔTR | of the gear ratio change amount is shifted to a state where the absolute value | ΔTR | of the gear ratio change amount is less than the determination value ΔTR_th from the state where the absolute value | ΔTR | Sometimes, it is highly possible that the clutch 121 has shifted from the disconnected state to the connected state. Therefore, a counter reference value Cnt_th is set as a value corresponding to the predetermined time KT.

  When the counter value Cnt is less than the counter reference value Cnt_th (step S20: NO), the brake ECU 30 proceeds to step S23 described later. On the other hand, if the counter value Cnt is greater than or equal to the counter reference value Cnt_th (step S20: YES), it can be determined that the transition from the disengaged state of the clutch 121 to the connected state has been completed, so the brake ECU 30 sets “0 (Zero) "is set (step S21). Subsequently, the brake ECU 30 acquires the driving force F currently transmitted to the wheel 10 and the current acceleration A of the vehicle as the driving force F2 and acceleration A2 when the clutch 121 is in the connected state (step S22). ), The process proceeds to step S23.

  In step S23, the brake ECU 30 determines whether or not the driving forces F1 and F2 and the accelerations A1 and A2 are acquired in both the case where the clutch 121 is in the disconnected state and the case where the clutch 121 is in the connected state. judge. When the driving forces F1 and F2 and the accelerations A1 and A2 in both states have not been acquired (step S23: NO), the brake ECU 30 proceeds to step S26 described later.

  On the other hand, when the driving forces F1 and F2 and the accelerations A1 and A2 in both states are acquired (step S23: YES), the brake ECU 30 acquires the driving force acquired in steps S19 and S22 in the above relational expression (formula 1). An estimated value M of the vehicle mass is obtained by substituting F1, F2 and accelerations A1, A2 (step S24). In this regard, in this embodiment, the brake ECU 30 determines that the difference between the driving force F1 when the clutch 121 is in a disconnected state and the driving force F2 when the clutch 121 is in a connected state, and that the clutch 121 is in a disconnected state. It also functions as a “mass calculation unit” that calculates an estimated value M of the vehicle mass according to the difference between the acceleration A1 at a certain time and the acceleration A2 when the clutch 121 is in a connected state. Then, the brake ECU 30 initializes the accelerations A1 and A2 and the driving forces F1 and F2 used for the calculation of the estimated value M of the vehicle mass, that is, sets it to the unacquired state (step S25), and proceeds to the next step S26. Transition.

In step S26, the brake ECU 30 adds one counter value Cnt. Thereafter, the brake ECU 30 once ends this processing routine.
Next, an example of the operation of the vehicle when the gear position is changed to the high speed side by the driver when the vehicle accelerates will be described with reference to the timing chart shown in FIG. Here, it is assumed that the driver operates the accelerator pedal 13 and the clutch pedal so that the engine speed NE and the wheel speed VW change in the manner shown in FIGS. 4 (a) and 4 (b).

  The engine speed NE and the wheel speed VW are sensor values detected by the crank angle sensor SE2 and the longitudinal acceleration sensor SE5. Therefore, as shown in FIGS. Is fluctuating. Therefore, the speed ratio TR and the speed ratio change amount ΔTR calculated according to the engine speed NE and the wheel speed VW also vary as shown in FIGS. 4 (g) and 4 (d). . Further, in FIG. 4D, in addition to the determination value ΔTR_th of the present embodiment, the determination value ΔTR_thC of the comparative example is drawn with a broken line. Furthermore, although the determination value ΔTR_th actually changes with a change in the wheel speed VW, the illustration of the change is omitted for the convenience of understanding the description.

  As shown in FIGS. 4 (a) and 4 (b), when the vehicle starts to travel with the speed of the transmission 122 being the first speed, the amount of operation of the accelerator pedal 13 by the driver increases. The engine speed NE and the wheel speed VW of the wheel 10 tend to increase. At this time, as shown in FIG. 4 (c), the speed ratio TR calculated according to the engine speed NE and the wheel speed VW fluctuates around the true speed ratio TR_T of the first speed gear stage. However, it is assumed that the fluctuation is within the speed ratio region of the first speed gear.

  Therefore, the current ECU is identified as the first gear by the brake ECU 30, and the determination value ΔTR_th is set to a value corresponding to the first gear as shown in FIG. Yes. Moreover, while the wheel speed VW increases, the determination value ΔTR_th decreases as the wheel speed VW increases (see FIG. 2).

  As described above, the magnitude of the gear ratio change amount ΔTR fluctuates due to the influence of the detection error of the engine speed NE and the wheel speed VW even when the gear position is not changed. Therefore, for example, as in the first timing t1, the absolute value | ΔTR | of the gear ratio change amount may increase. If the determination value ΔTR_thC is fixed at a small value as in the comparative example, the absolute value | ΔTR | of the gear ratio change amount becomes equal to or larger than the determination value ΔTR_thC at the first timing t1, and the clutch 121 In spite of being connected, there is a possibility that the clutch 121 is erroneously determined to be in a disengaged state.

  As a method for avoiding such erroneous determination, there is a method of increasing the determination value ΔTR_thC. In this method, the possibility that the clutch 121 is erroneously determined to be in the disconnected state when the clutch 121 is in the connected state is reduced. However, when the engine speed NE does not change much during the gear shifting operation by the driver, the gear ratio change amount ΔTR calculated within this period does not vary so much, so that the clutch 121 is in the disengaged state. The clutch 121 may not be determined to be in a disconnected state.

  On the other hand, in the present embodiment, the determination value ΔTR_th is set to a larger value as the specified shift speed is the lower speed shift speed and the wheel speed VW is lower. Therefore, unlike the case of the comparative example, at the first timing t1, the absolute value | ΔTR | of the gear ratio change amount does not exceed the determination value ΔTR_th, so that it is erroneously determined that the clutch 121 is in the disengaged state. There is no.

  Then, when the second timing t2 is reached, the speed change operation of the transmission 122 is started by the driver. That is, the clutch 121 is disconnected by the operation of the clutch pedal by the driver, and the operation amount of the accelerator pedal 13 is reduced. Then, as shown in FIGS. 4 (a) and 4 (b), the engine speed NE, which has been increasing, starts to decrease, and the wheel speed VW, which has been increasing, becomes a constant speed. Here, for convenience of explanation, from the second timing t2 when the clutch 121 is disengaged to the fifth timing when the connection of the clutch 121 is completed, the vehicle travels inertially so that the wheel speed VW is constant. Shall.

  In the middle of a decrease in the operation amount of the accelerator pedal 13, the driving force output from the engine 11 becomes smaller as the operation amount of the accelerator pedal 13 decreases. Then, when the operation of the accelerator pedal 13 by the driver is canceled, the engine speed NE decreases in accordance with the decreasing gradient shown in FIG. Subsequently, when the shift stage of the transmission 122 is changed to the second speed stage by the driver operating the shift lever, the operation amount of the clutch pedal is decreased and the operation amount of the accelerator pedal 13 is increased. The Then, the power transmission efficiency from the engine 11 to the wheel 10 side via the clutch 121 increases, and the driving force output from the engine 11 also increases. As a result, the engine speed NE increases.

  Therefore, after the second timing t2, as shown in FIGS. 4C and 4D, the transmission gear ratio TR tends to decrease and the absolute value | ΔTR | of the transmission gear ratio change amount tends to increase. become. When the third timing t3 is reached, the absolute value | ΔTR | of the gear ratio change amount becomes equal to or greater than the determination value ΔTR_th, and it is determined that the clutch 121 is in a disengaged state. After the fourth timing t4 thereafter, the decreasing gradient of the engine speed NE gradually becomes gentle, so that the absolute value | ΔTR | of the speed ratio change amount also gradually decreases.

  When the fifth timing t5 is reached, the absolute value | ΔTR | of the speed ratio change amount becomes less than the determination value ΔTR_th, and it is determined that the clutch 121 is not in the disengaged state. That is, the period from the third timing t3 to the fifth timing t5 is a period during which acquisition of the driving force F1 and the acceleration A1 is permitted. Then, the operation of the clutch pedal by the driver is canceled between the fifth timing t5 and the next sixth timing t6, and the connection of the clutch 121 is completed at the sixth timing t6.

  In the present embodiment, the elapsed time from the fifth timing t5 is measured. When this elapsed time reaches the predetermined time KT, it is determined that the clutch 121 is in a connected state. Therefore, from the fifth timing t5 to the seventh timing t7 when the elapsed time reaches the predetermined time KT, the driving force F2 and the acceleration A2 when the clutch 121 is in the connected state are not acquired. In the present embodiment, the elapsed time from the fifth timing t5 reaches the predetermined time KT at the seventh timing t7 after the sixth timing t6 at which the clutch 121 is actually engaged.

  However, at the sixth timing t6, the clutch 121 is in the connected state. Therefore, after the sixth timing t6, the gear ratio TR calculated according to the engine speed NE and the wheel speed VW varies within the gear ratio region of the second gear stage. Further, the gear ratio change amount ΔTR varies around “0 (zero)”. As a result, at the sixth timing t6, since the selected shift speed is specified as the second speed, the determination value ΔTR_th corresponds to the second speed and the wheel speed VW at that time. The value is set to be smaller than before the sixth timing t6.

  From the sixth timing t6 to the eighth timing t8 after the seventh timing t7, the engine speed NE is maintained with the gear stage of the transmission 122 being fixed at the second gear stage. And the wheel speed VW shows an increasing tendency. Therefore, the determination value ΔTR_th gradually decreases as the wheel speed VW increases.

  Thereafter, when the eighth timing t8 is reached, a gear shift operation is started to change the gear position of the transmission 122 from the second gear to the third gear. Then, as in the second timing t2 to the sixth timing t6, the engine speed NE fluctuates and the wheel speed VW is maintained at the speed at the eighth timing t8. As a result, the speed ratio TR shows a decreasing tendency, and the absolute value | ΔTR | of the speed ratio change amount shows a decreasing tendency after showing an increasing tendency. Then, during the period from the ninth timing t9 to the tenth timing t10, the absolute value | ΔTR | of the gear ratio change amount becomes equal to or greater than the determination value ΔTR_th at that time. That is, this period is a period during which it is determined that the clutch 121 is in a disconnected state.

  When the eleventh timing t11 thereafter is reached, the gear ratio TR calculated in accordance with the engine speed NE and the wheel speed VW varies within the gear ratio region of the third gear stage. Further, the gear ratio change amount ΔTR varies around “0 (zero)”. As a result, at the eleventh timing t11, since the selected shift speed is specified as the third speed, the determination value ΔTR_th corresponds to the third speed and the wheel speed VW at that time. The value is set to be smaller than before the eleventh timing t11.

As described above, in the present embodiment, the following effects can be obtained.
(1) The determination value ΔTR_th is set to a larger value when the wheel speed VW is smaller than when the wheel speed VW is large. For this reason, when the low speed side gear stage is selected as the gear stage, even if the gear ratio change amount ΔTR fluctuates relatively large due to an error included in the wheel speed VW detected by the wheel speed sensor SE4. The absolute value | ΔTR | of the same gear ratio change amount is less likely to be greater than or equal to the determination value ΔTR_th. For this reason, when the clutch 121 is in a connected state, the possibility of erroneous determination that the clutch 121 is in a disconnected state is reduced. Therefore, it becomes possible to improve the determination accuracy of whether or not the clutch 121 is in the disengaged state.

  (2) In the present embodiment, the determination value ΔTR_th is larger when the identified shift speed is the low speed shift speed than when the identified shift speed is the high speed shift speed. Therefore, even when the clutch 121 is in the engaged state, the absolute value | ΔTR | of the speed ratio change amount is less than or equal to the determination value ΔTR_th at that time when the vehicle travels at a low speed where the speed ratio change amount ΔTR varies relatively greatly. Become. As a result, it is possible to reduce the possibility of erroneous determination that the clutch 121 is in a disconnected state when the clutch 121 is in a connected state.

  (3) On the other hand, when the vehicle in which the gear ratio change amount ΔTR does not fluctuate so much is high speed, the specified shift speed becomes the high speed shift speed, so that the determination value ΔTR_th is smaller than that at low speed. It will be set to a smaller value. Therefore, when the clutch 121 shifts from the connected state to the disconnected state, it can be early determined that the clutch 121 is in the disconnected state.

  (4) In the present embodiment, even when the gear position is not changed, the determination value ΔTR_th gradually decreases as the wheel speed VW increases. Therefore, when the gear position of the transmission 122 is changed, the higher the wheel speed VW, the earlier it can be determined that the clutch 121 is in a disconnected state.

  (5) The driving force F1 and acceleration A1 when the clutch 121 is in the disengaged state and the clutch 121 are in the connected state, so that it can be accurately determined whether or not the clutch 121 is in the disengaged state. The calculation accuracy of the estimated value M of the vehicle mass using the driving force F2 and the acceleration A2 at the time can be improved.

The above embodiment may be changed to another embodiment as described below.
The determination value ΔTR_th may be decreased as the wheel speed VW increases regardless of the selected gear stage of the transmission 122. In this case, the decrease gradient of the determination candidate value CV is equivalent to the gradient of the line connecting the lower limit values VW1_min, VW2_min, and VW3_min of the wheel speed region corresponding to each shift speed shown in FIG. 5 is preferably a two-point difference line) or a gentler gradient (solid line in FIG. 5) than the same gradient. Even in this case, when the clutch 121 is in the connected state, it is difficult to erroneously determine that the clutch 121 is in the disconnected state.

  The determination value ΔTR_th may not be the determination candidate value CV corresponding to the changed gear position when the gear position of the transmission 122 is changed. For example, when the first speed gear stage is changed to the second speed gear stage, the first speed gear stage until the wheel speed VW reaches the upper limit value VW1_max of the wheel speed region of the first speed gear stage. The determination candidate value CVG1 may be used. By adopting such a control configuration, it is possible to further reduce the possibility of erroneous determination that the clutch 121 is in a disconnected state when the clutch 121 is in a connected state.

  In this case, as a map for determining the determination value ΔTR_th, for example, a map shown in FIG. 6 may be adopted. That is, as shown in FIG. 6, this map includes a plurality of wheel speed regions VWA1, VWA2, and VWA3, and determination candidate values CV (CVV1, CVV2, CVV3) individually corresponding to these wheel speed regions VWA1 to VWA3. Shows the relationship. In this case, the first region VWA1 may be a region from the lower limit value VW1_min to the upper limit value VW1_max of the wheel speed region of the first speed gear. And while wheel speed VW is contained in 1st field VWA1, you may make judgment candidate value CVV1 small, so that wheel speed VW is large.

  The second region VWA2 may be a region from the upper limit value VW1_max of the wheel speed region of the first speed gear to the upper limit value VW2_max of the wheel speed region of the second speed gear. Good. And while wheel speed VW is contained in 2nd field VWA2, you may make judgment candidate value CVV2 small, so that wheel speed VW is large.

  The third region VWA3 may be a region from the upper limit value VW2_max of the wheel speed region of the second speed gear to the upper limit value VW3_max of the wheel speed region of the third speed gear. Good. Then, while the wheel speed VW is included in the third region VWA3, the determination candidate value CVV3 may be decreased as the wheel speed VW increases.

  When adopting such a map, the brake ECU 30 may specify in which region VWA (VWA1 to VWA3) the wheel speed VW is included instead of specifying the gear stage of the transmission 122. That is, the brake ECU 30 may also function as an “area specifying unit”. Then, the brake ECU 30 extracts the determination candidate value CV corresponding to the specified region VWA and the wheel speed VW at that time from the map shown in FIG. 6, and sets the determination candidate value CV as the determination value ΔTR_th. Also good.

  According to this configuration, when the specified region VWA shifts to the high speed region in the process of increasing the wheel speed VW, the determination value ΔTR_th becomes smaller than before. In other words, the determination value ΔTR_th is larger when the specified region VWA is a low speed region than when it is a high speed region. Therefore, even when the clutch 121 is in the engaged state, the absolute value | ΔTR | of the speed ratio change amount is less than or equal to the determination value ΔTR_th at that time when the vehicle travels at a low speed where the speed ratio change amount ΔTR varies relatively greatly. Become. As a result, it is possible to reduce the possibility of erroneous determination that the clutch 121 is in a disconnected state when the clutch 121 is in a connected state.

  On the other hand, the determination value ΔTR_th is set to a smaller value when the vehicle where the gear ratio change amount ΔTR does not fluctuate significantly is higher than when the vehicle is traveling at a low speed. Therefore, when the clutch 121 shifts from the connected state to the disconnected state, it can be early determined that the clutch 121 is in the disconnected state.

  The upper limit value of the first region VWA1 and the lower limit value of the second region VWA2 may be set as the lower limit value VW2_min of the wheel speed region of the second speed gear, and the lower limit value VW2_min and the first speed It may be an arbitrary value between the lower limit value VW1_min of the wheel speed region of the gear stage. Further, the upper limit value of the second region VWA2 and the lower limit value of the third region VWA3 may be set as the lower limit value VW3_min of the wheel speed region of the third speed gear, and the lower limit value VW3_min and the second speed It may be an arbitrary value between the lower limit value VW2_min of the wheel speed region of the gear stage.

Further, in the map shown in FIG. 6, the determination candidate values CVV1 to CVV3 may be constant in each of the regions VWA1 to VWA3.
In the above embodiment, when the specified shift speed is not changed, the determination value ΔTR_th may not be changed even if the wheel speed VW changes.

The clutch state determination may be performed when the vehicle travels while changing the shift speed from the high speed shift speed to the low speed shift speed.
The wheel speed VW used for calculating the gear ratio TR may be the wheel speed of the specific wheel 10 or may be the average value of the wheel speeds of the wheels 10.

  When specifying the gear stage of the selected transmission 122, the gear ratio TR may be calculated a predetermined number of times (for example, five times), and the average value of the calculated values may be used as the gear ratio TR. Then, the gear position may be specified based on the gear ratio TR. For example, when the gear ratio TR is a value between the upper limit value of the gear ratio region corresponding to a certain gear stage and the lower limit value of the gear ratio region corresponding to the next higher gear stage, You may make it identify with the side gear position, and you may make it identify with the gear stage corresponding to the gear ratio with the nearer gear ratio TR.

The transmission ratio change amount ΔTR may be a change amount of the transmission ratio TR per two or more cycles.
The accelerations A1 and A2 and the driving forces F1 and F2 may not be acquired when a braking force is applied to the vehicle (wheel 10).

The average value of the plurality of driving forces F1 and the average value of the plurality of accelerations A1 acquired while it is determined that the clutch 121 is in the disengaged state may be used for the calculation of the estimated value M of the vehicle mass.
Similarly, the driving force F2 and the acceleration A2 are acquired a predetermined number of times (for example, five times) after the counter value Cnt becomes equal to or greater than the counter determination value Cnt_th, and the average value of each driving force F2 and the average value of each acceleration A2 May be used for calculation of the estimated value M of the vehicle mass.

  -The estimated value M of the vehicle mass is calculated by considering the terms corresponding to the air resistance, road resistance, and road surface gradient that can act on the vehicle in the equation of motion when calculating the estimated value M of the vehicle mass. May be.

  The vehicle may be equipped with a sensor that can detect the operation mode of the clutch pedal and the mode of the clutch 121. In this case, when such a sensor abnormality occurs, it may be determined whether or not the clutch 121 is disengaged by the above processing routine.

  The determination of the clutch state and the calculation of the estimated value M of the vehicle mass may be performed by the engine ECU 14 or a dedicated ECU. In this case, the ECU that performs such processing functions as a clutch state determination device or a vehicle mass estimation device.

Next, the technical idea that can be grasped from the above embodiment and another embodiment will be added below.
(A) A plurality of judgment candidate values individually corresponding to the respective speed stages of the transmission are prepared in advance, and the judgment candidate value corresponding to the high speed side gear stage is more than the judgment candidate value corresponding to the low speed side gear stage. It is preferable that the setting unit sets the determination value to a determination candidate value corresponding to the shift stage specified by the shift stage specifying unit.

  DESCRIPTION OF SYMBOLS 10 ... Wheel, 14 ... Engine ECU as an example of clutch state determination apparatus and vehicle mass estimation apparatus, 30 ... Brake ECU (calculation part, determination part, example of clutch state determination apparatus and vehicle mass estimation apparatus) Setting unit, gear position specifying unit, region specifying unit, mass calculating unit), 121 ... clutch, 122 ... transmission, SE2 ... crank angle sensor as an example of engine speed sensor, SE4 ... wheel speed sensor, NE ... engine rotation Number, NW: wheel rotation speed, VW: wheel speed, TR: speed ratio, ΔTR: speed ratio change amount, | ΔTR |: absolute value of speed ratio change amount, ΔTR_th: judgment value, CV: judgment candidate value, VWA: Area, A1, A2 ... acceleration, F1, F2 ... driving force, M ... estimated value of vehicle mass.

Claims (3)

An arithmetic unit that calculates a transmission gear ratio and a gear ratio change amount, which is a change amount with respect to time, of the transmission gear ratio according to the engine speed detected by the engine speed sensor and the wheel speed detected by the wheel speed sensor. When,
A determination unit that determines that the clutch is disengaged when the absolute value of the calculated gear ratio change amount is equal to or greater than a determination value;
A setting unit that sets the determination value to a larger value than when the wheel speed is large when the wheel speed is small;
A shift stage identifying unit that identifies a shift stage of the selected transmission based on the gear ratio calculated by the calculation unit;
The setting unit
When the shift stage of the transmission specified by the shift stage specifying unit is changed to a high speed side shift stage, the determination value is set to a value smaller than that before the specified shift stage is changed,
Clutch state determination that sets the determination value to a value larger than that before the change of the specified shift stage when the shift stage of the transmission specified by the shift stage specifying unit is changed to a low speed shift stage. apparatus. An arithmetic unit that calculates a transmission gear ratio and a gear ratio change amount, which is a change amount with respect to time, of the transmission gear ratio according to the engine speed detected by the engine speed sensor and the wheel speed detected by the wheel speed sensor. When,
A determination unit that determines that the clutch is disengaged when the absolute value of the calculated gear ratio change amount is equal to or greater than a determination value;
A setting unit that sets the determination value to a larger value when the wheel speed is small than when the wheel speed is large ;
Determination candidate values are prepared in advance for each wheel speed region,
The determination candidate value is a smaller value as the wheel speed is higher,
An area specifying unit for specifying which area the wheel speed is included in is further provided,
The setting unit sets the determination value to a determination candidate value corresponding to the region specified by the region specifying unit.
A clutch state determination device. The difference between the driving force transmitted to the wheel when the clutch is disengaged and the driving force transmitted to the wheel when the clutch is engaged, and the acceleration of the vehicle when the clutch is disengaged And a vehicle mass estimation device including a mass calculation unit that calculates an estimated value of the vehicle mass according to the difference between the acceleration of the vehicle when the clutch is in the connected state,
Vehicle mass estimation apparatus further comprising a determination device of a clutch according to claim 1 or claim 2.