Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T7/00—Brake-action initiating means
  • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
  • B60T7/122—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger for locking of reverse movement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2552/00—Input parameters relating to infrastructure
  • B60W2552/15—Road slope, i.e. the inclination of a road segment in the longitudinal direction

Definitions

• the present invention relates to a system and a method for controlling the release of an automatic parking brake device on board a motor vehicle.
• the manual braking device makes it possible to ensure mechanically, without external energy supply, that the vehicle will be kept in the idle state, even if he undergoes moderate actions to set it in motion.
• the manual braking device makes it possible to maintain a vehicle on a hill when the gear ratio is changed without the vehicle descending, since, most often, a gearbox shift is preceded by a disengagement of the motive power which is disconnected from the wheels, leaving the vehicle under the action of gravity and inertia on the ramp.
• automatic parking brake devices have been developed to replace manual parking brakes. They are associated with a computer that allows, according to various signals representative of engine operating parameters, to achieve a release of the brakes without direct intervention of the driver of the vehicle.
• French Patent Application No. 2,828,450 discloses a control system for the release of an automatic parking brake device, on board a motor vehicle, in which, when conditions representative of a starting or side maneuver are performed, a release command of the parking brake is issued a plurality of times, to brake actuators.
• a failure of the sensor for detecting the neutral position of the shift lever or the gear lever reverse position sensor such a system may control the release of the parking brake device as a result of false information transmitted by the vehicle. minus one of these two sensors, while the parking brake device must not be loosened.
• An object of the invention is to provide a system and a method for controlling the release of an automatic parking brake device which avoids a refusal to release the parking brake. failure or malfunction of the neutral position sensor and / or the reverse gear position sensor.
• a control system for loosening an automatic parking brake device on board a motor vehicle, and comprising means for estimating the torque transmitted by the vehicle. clutch, a sensor for measuring the angle of inclination of the rolling surface, and means for controlling the release of the parking brake device provided with first means for comparing the torque transmitted by the clutch with a threshold torque. continuous depending on the angle of inclination of the running surface at the end of a stopping of the vehicle.
• the threshold torque is an even function of the inclination angle of the taxiing surface at the end of a vehicle stop, and includes a first decreasing portion for values of the angle of inclination of the vehicle surface.
• the release of the parking brake when moving on an inclined taxiing surface will prevent damage to the brakes, calipers and tires having the same loosening conditions when the vehicle is moving in the direction of the slope or in the direction of the coast.
• the means for estimating the torque transmitted by the clutch comprise first means for subtracting a first torque value corresponding to the maximum error, in absolute value, for estimating the torque transmitted by the clutch. ' clutch.
• the accuracy of the operation of the system is thus improved, and the driver is sure to be able to set the vehicle in motion when the transmitted torque is sufficient.
• the means for estimating the torque transmitted by the clutch comprise means for calculating a second torque value transmitted to elements connected to the motor, and second means for subtracting said second torque value. , when estimating the torque transmitted by the clutch.
• the accuracy of the operation of the device is improved, by avoiding counting in the available torque for starting, a torque used or absorbed by ancillary elements connected to the engine.
• the system includes an engine power control pedal and a power control pedal position sensor.
• the means for controlling the release of the parking brake device are, in addition, provided with second means for comparing the position of the engine power control pedal with a threshold position.
• the means for controlling the release of the parking brake device comprise a mapping of the threshold position of the power control pedal, depending on the speed of rotation of the engine and the absolute value of the angle of inclination of the running surface at the end of a stop of the vehicle.
• a stopping of the vehicle corresponds to a phase during which its speed is substantially zero or less than a minimum speed.
• the means for controlling the release of the parking brake device are, in addition, provided with third means for comparing the speed of rotation of the motor with a threshold rotation speed.
• the means for controlling the release of the parking brake device are adapted to release the parking brake device when the vehicle is stationary, that the driver controls the setting in motion of the vehicle, and that the torque transmitted by the clutch is greater than the threshold torque, the position of the engine power pedal is greater than the threshold position, and the engine rotation speed is greater than the threshold rotation speed.
• the system further includes a clutch control pedal, a clutch pedal position sensor, and fourth means for comparing another torque estimate transmitted. by the clutch with said threshold torque.
• the other estimate of the torque transmitted by the clutch is delivered by mapping according to the position of the clutch pedal.
• the means for controlling the release of the parking brake device are adapted to release the parking brake device when the vehicle is stationary, when the driver commands a start or an uphill maneuver, and the torque transmitted by the clutch is greater than the threshold torque, the position of the engine power pedal is greater than the threshold position, the engine rotation speed is greater than the threshold rotation speed, and the other estimate of the torque transmitted by the clutch is greater than the threshold torque.
• a method for controlling the release of an automatic parking brake device on board a motor vehicle in which the torque transmitted by the clutch is compared with a continuous threshold torque dependent on the angle of inclination of the running surface at the end of a stopping of the vehicle.
• the threshold torque is an even function of the inclination angle of the taxiing surface at the end of a vehicle stop, and includes a first decreasing portion for values of the angle of inclination of the vehicle surface.
• FIG. schematic diagram of a control system of the release of an automatic parking brake device according to one aspect of the invention
• Figure 2 schematically illustrates the threshold torque with which is compared the torque transmitted by the clutch
• FIG. 3 is a state diagram illustrating the detection of a request to start the vehicle on an inclined taxiing surface after a stopping period during which the vehicle's automatic parking brake device has been activated, for a system according to Figure 1
• FIG. 4 schematically illustrates a control system for loosening an automatic parking brake device, in which the vehicle is equipped with a manual gearbox
• FIG. 5 is a state diagram illustrating the detection of a request to start the vehicle on an inclined taxiing surface after a stopping period during which the automatic parking brake device of the vehicle has been activated, for a system according to Figure 4.
• Figure 1 illustrates an example of a control system 1 of the release of an automatic parking brake device 2 on board a motor vehicle.
• the vehicle may include a manual, automatic or robotic gearbox.
• the system includes an estimation module 3 of the ECT torque transmitted by the clutch, a sensor 4 for measuring the angle of inclination ⁇ t ⁇ t of the running surface of the vehicle, and a control module 5 for loosening the parking brake device 2.
• the control module 5 comprises a first comparison module 6 of the ECT couple transmitted by the clutch with a threshold torque CT that is used.
• the ECT torque transmitted by the clutch is supplied by the estimation module 3 to the first module. Comparison 7 via a connection 7.
• a memorized map 8 of the control module 5 supplies the first comparison module 6 with a threshold torque CT 86U i I via a connection 9, as a function of the frozen inclination angle ⁇ tiit frozen of the running surface of the vehicle delivered by a storage module 16, via a connection 10.
• the system comprises a power control pedal 1 1 of the motor, or accelerator pedal, and an associated position sensor 12 outputting the position ⁇ acc of the power control pedal 1 1 to a second comparison module 13 by a connection 14.
• the second comparison module 13 compares the position ⁇ acc of the power control pedal 1 1 with a threshold position ⁇ acc threshold provided by a map 15 as a function of the speed of rotation of the engine ⁇ m , measured by a sensor or estimated by an estimator, and the absolute value ⁇ tllt frozen of the angle of inclination ⁇ t ⁇ t frozen of the running surface at the end of a stopping of the vehicle.
• the storage module 16 stores the value of the angle of inclination ⁇ tiit provided by the measurement sensor 4 by a connection
• the mapping of the position of threshold ⁇ acc threshold receives the value of the inclination angle of the running surface at the end of a stopping of the vehicle by a connection 18 derived from the connection 10, and the speed of rotation of the motor via a connection 19.
• the control module 5 further comprises a third comparator module 20 for the speed of rotation ⁇ m of the motor, received via a connection 21, with a threshold rotation speed ⁇ m stored in a memory or estimated by an estimator and received by a connection 22.
• the control module 5 is adapted to control, by a connection 23, the loosening of the parking brake device 2, when the vehicle is stationary, or, in other words , at a speed substantially zero or less, in absolute value, at a minimum speed v min , when the driver requests a motion of the vehicle, and the ECT torque transmitted by the clutch is greater than the threshold torque CT seU ii , the position ⁇ acc of the a motor power pedal 1 1 is greater than the threshold position ⁇ acc threshold, and the motor rotation speed ⁇ m is greater than the threshold rotation speed ⁇ m si uii-
• These comparisons are made by the first second and third comparison modules 6, 13 and 20.
• the estimation module 3 may comprise a first subtraction module 24 for subtracting a first torque value corresponding to the maximum of errors in absolute value, when estimating the ECT torque transmitted by the clutch.
• the estimation module 3 may also include, optionally, a module for calculating a second torque value transmitted to elements connected to the engine of the vehicle, and a second subtraction module 26 of said second torque value, when estimating the torque transmitted by the clutch.
• the calculation module 25 transmits to the second subtraction module 26 the second torque value via a connection 27.
• FIG. 2 represents the determination of the threshold torque
• CTseuii as a function of the frozen inclination angle ⁇ t ⁇ t frozen of the running surface. This determination is carried out by the map 8, or, alternatively, by a calculation module using a function representative of the curve of FIG. 2.
• the dotted curve represents a threshold pair
• CT threshold couple uii comprises a first decreasing portion for values of the angle of inclination of the lower rolling surface at a first negative threshold seuili, a second constant and positive portion for values of the angle of inclination of the rolling surface between the first negative threshold and a second positive threshold threshold, and a third increasing portion for values of the inclination angle of the rolling surface greater than the second threshold positive threshold.
• the threshold torque CT sem i can be defined by the following system: r max -P wheels .mg Sin ( ⁇ tll _ IIlln ) Sl ⁇ tilt frozen ⁇ ⁇ tilt min r max -P wheels F tilt _ frozen> ⁇ tilt mm in which: r max is the maximum of the ratio r (l) of the first speed and ratio r (- l) of the reverse gear; and ⁇ t ⁇ t mm is a predetermined parameter making it possible to avoid having a zero threshold torque when the inclination of the rolling surface is small, ie between the thresholds seuih and seuih.
• CT seml classic r ( b) - p mgsin wheels ( ⁇ tllt ) in which: r (b) is the gear ratio corresponding to the position b of the gear lever.
• semiclassical CT is fixed at 0 Nm;
• P ⁇ e wheels is radius of the vehicle wheels, in m;
• m is the mass of the vehicle, in kg,
• ⁇ t is the inclination of the running surface of the vehicle, in rad;
• g is the gravitational field on the surface of the Earth, substantially equal to 9.81 m.
• C M is the torque supplied by the engine, in Nm; J M is the inertia of the engine, in kg. m 2 . rad “1 ; and ⁇ M is the time derivative of the rotational speed of the motor, in rads s " 2 .
• FIG. 3 illustrates the operation of a system according to FIG. 1.
• the state 30 corresponds to the vehicle traveling at a speed v such that its absolute value is greater than a minimum speed v min and the driver has decreased his power demand by so that the position ⁇ acc of the power control pedal 1 1 is less than a minimum position ⁇ acc min for a duration ⁇ T stop .
• the system enters a state 31 wherein the vehicle is considered stopped for the duration .DELTA.T RIOs and
• state 32 when the vehicle is ready to be set in motion, if the driver releases his support on the power control pedal 1 1, so that the position ⁇ acc of the power control pedal 1 1 is less than the minimum position ⁇ acc mm, the system returns to the state 31, in which the vehicle is considered as stopped for a period ⁇ T stops . If the speed of the vehicle becomes higher, in absolute value, at the minimum speed v mm , the system returns to state 30, in which the vehicle is considered to be running. On the other hand, if the test conditions carried out by the first, second and third comparators 6, 13 and 20 of the control module 5 correspond to the conditions previously defined for a release control of the parking brake device 2, the system switches to a state 33 for which the parking brake device is loosened.
• a duration ⁇ T greater than a duration ⁇ T comman d e corresponding to the maximum duration of loosening of the brakes, for example a second, if the position ⁇ acc of the power control pedal 1 1 is greater than the minimum position ⁇ acc min , and the absolute value of the vehicle speed is lower than the minimum speed v min , the system reverts to state 32, and otherwise returns to state 30.
• FIG. 4 illustrates another example of a control system 1 for loosening an automatic parking brake device 2 on board a motor vehicle, for a vehicle equipped with a manual gearbox.
• the system comprises a fourth comparison module 40 of another estimate ECT em b of the torque transmitted by the clutch with the threshold torque CT being transmitted by a connection 41 derived from the connection 9.
• the other estimate ECT em b of the torque transmitted by the clutch is provided by a map 42, via a connection 43.
• the map 42 outputs, through a connection 46, the other estimate ECT em b of the torque transmitted by the clutch from the position ⁇ c i Utch a control pedal 44 of the clutch, measured by a position sensor 45 associated with the control pedal 44 of the clutch.
• the operation of the control system is thus improved because it takes into account two estimates of the torque transmitted by the clutch.
• Figure 5 is a state diagram illustrating the operation of the system of Figure 4, for a vehicle equipped with a manual gearbox.
• the state 30 corresponds to the vehicle traveling at a speed v such that its absolute value is greater than a minimum speed v min and the driver has reduced his power demand so that the position ⁇ ciutch of the clutch control pedal 44 is less than a minimum position ⁇ clu tch_min for a duration ⁇ T stop t.
• the system goes into a state 31, in which the vehicle is considered as stopped during the period ⁇ T stops
• state 32 when the vehicle is ready to be set in motion, if the driver releases his support on the power control pedal 1 1, so that the position ⁇ acc of the power control pedal 1 1 is less than the minimum position ⁇ acc mm, the system returns to the state 31, in which the vehicle is considered as stopped for a period ⁇ T stops . If the speed of the vehicle becomes higher, in absolute value, at the minimum speed v mm , the system returns to state 30, in which the vehicle is considered to be running. On the other hand, if the test conditions carried out by the first, second and third comparators 6, 13 and 20 of the control module 5 correspond to the conditions previously defined for a release control of the parking brake device 2, the system switches to a state 33 for which the parking brake device is loosened.
• the invention makes it possible to prevent a vehicle equipped with a control system from loosening a brake device of automatic parking, remains locked in the event of a fault or malfunction of the sensor for detecting the neutral position of the shift lever or the gear lever reverse position sensor.

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Regulating Braking Force (AREA)
• Mechanical Control Devices (AREA)
• Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=39333140

Family Applications (1)

Country Status (7)

Families Citing this family (22)

Citations (1)

Family Cites Families (7)

• 2007
  • 2007-08-31 FR FR0757286A patent/FR2920381B1/fr not_active Expired - Fee Related
• 2008
  • 2008-06-30 CN CN2008801116883A patent/CN101827737B/zh not_active Expired - Fee Related
  • 2008-06-30 EP EP08806129A patent/EP2183139A2/de not_active Withdrawn
  • 2008-06-30 JP JP2010522416A patent/JP2010537870A/ja active Pending
  • 2008-06-30 US US12/675,793 patent/US20100262329A1/en not_active Abandoned
  • 2008-06-30 KR KR1020107006914A patent/KR20100046280A/ko not_active Withdrawn
  • 2008-06-30 WO PCT/FR2008/051203 patent/WO2009030844A2/fr not_active Ceased

Patent Citations (1)

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