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EP-4561858-B1 - METHOD FOR CONTROLLING AN ELECTRIC TRACTION MACHINE OF A VEHICLE

EP4561858B1EP 4561858 B1EP4561858 B1EP 4561858B1EP-4561858-B1

Inventors

  • BALENGHIEN, Olivier
  • LE CLERC, Jean Francois

Dates

Publication Date
20260513
Application Date
20230601

Claims (10)

  1. Method (100) for controlling a traction electric machine (2) of an electric or hybrid vehicle (1), said method (100) comprising, when said vehicle (1) is moving, the steps, executed by control means (9) of said vehicle (1), of: - Detecting (101) a failure of at least one first pressure sensor (6) or a second pressure sensor (7) of a brake booster (4) of said vehicle (1), - Determining (102) a speed value of said vehicle (1), - Said method (100) being characterized in that it further comprises the steps of: o When a failure of at least one of the first pressure sensor (6) or second pressure sensor (7) is detected, determining (103) a torque value to be applied to driving wheels (3) of said vehicle (1), as a function of said determined speed value, in order to bring said vehicle (1) to a predetermined safety speed value, o Applying (104) said determined torque value to said driving wheels (3) by means of said traction electric machine (2).
  2. Method (100) according to claim 1, characterized in that it comprises a step, executed by the control means (9), of displaying (105), on a display console (8) of said vehicle (1), a vehicle stop warning indicator.
  3. Method (100) according to any one of the preceding claims, characterized in that it comprises a step, executed by the control means (9), of displaying (106), on a display console (8) of said vehicle (1), a message reflecting that a failure of at least one of the first pressure sensor (6) or second pressure sensor (7) of the vehicle (1) has been detected.
  4. Method (100) according to any one of the preceding claims, characterized in that the step of detecting (101) a failure of at least one of the first pressure sensor (6) or second pressure sensor (7) comprises the sub-steps of: - Receiving (101a) a first pressure measurement of the brake booster (4) determined by means of the first pressure sensor (6), - Receiving (101b) a second pressure measurement of the brake booster (4) determined by means of the second pressure sensor (7), - Determining (101c) a pressure deviation between the first and second pressure measurements, - Repeating (101d), periodically according to a determined first period, the sub-steps of receiving (101a) a first pressure measurement, receiving (101b) a second pressure measurement and determining (101c) a pressure deviation, - If said determined pressure deviation is greater than a pressure threshold during a predetermined second period, determining (101e) a failure of at least one of the first pressure sensor (6) or second pressure sensor (7).
  5. Method (100) according to the preceding claim, characterized in that it comprises a step, executed by the control means (9), of controlling (107) a vacuum pump (5) of the brake booster (4) as a function of the lowest pressure measurement among the first and second pressure measurements.
  6. Method (100) according to any one of claims 4 or 5, characterized in that when a failure of at least one of the first pressure sensor (6) or second pressure sensor (7) has been detected, it comprises the steps, executed via the control means (9), of: - Repeating (109) periodically according to the determined first period, the sub-steps of receiving (101a) a first pressure measurement, receiving (101b) a second pressure measurement and determining (101c) a pressure deviation, - If said determined pressure deviation is lower than the pressure threshold during a predetermined third period, determining (110) a restoration of operation of at least one of the first pressure sensor (6) or second pressure sensor (7).
  7. Method (100) according to the preceding claim, characterized in that it comprises a step, executed by the control means (9), of stopping (111) the application of the determined torque value to the driving wheels (3) by means of the traction electric machine (2).
  8. Method (100) according to any one of claims 6 or 7 characterized in that it comprises a step, executed by the control means (9), of switching off (112) the vehicle stop warning indicator (1).
  9. Method (100) according to any one of claims 6 to 8, characterized in that it comprises a step, executed by the control means (9), of switching off (113) the message reflecting that a failure of at least one of the first pressure sensor (6) or second pressure sensor (7) has been detected.
  10. Method (100) according to any one of claims 6 to 9, characterized in that it comprises a step, executed by the control means (9), of controlling (114) a vacuum pump (5) of the brake booster (4) as a function of a pressure measurement carried out by the first pressure sensor (6) or the second pressure sensor (7) preselected as reference sensor.

Description

The present invention claims priority of application French application No. 2207844 filed on 29.07.2022 the content of which (text, drawings and claims) is incorporated herein by reference. One aspect of the invention relates to a method of controlling an electric traction machine of a vehicle, said control taking place successively to the detection of a failure of at least one pressure sensor of a braking amplifier included in the vehicle. Another aspect of the invention relates to an electric or hybrid vehicle, in particular an automobile, constructed and arranged to implement a method of controlling an electric traction machine. These aspects of the invention have particularly interesting applications in the field of safety for electric or hybrid motor vehicles. A brake booster is typically installed on a motor vehicle to amplify the force a driver must exert on the brake pedal. To achieve this, the brake booster works in conjunction with an electric vacuum pump designed to generate a vacuum within the vehicle's brake booster. Each time the brake pedal is pressed, vacuum is consumed to provide the necessary braking assistance to the driver. As soon as the vacuum level drops below a predetermined threshold, the electric vacuum pump activates to replenish the vacuum in the brake booster. The pressure generated by the vacuum pump in the brake booster is monitored by a pressure sensor. Specifically, this pressure sensor transmits pressure information to a vehicle control unit, which verifies that the detected pressure value is within an acceptable range. If the value falls outside this range, the pressure sensor is considered faulty. In order to detect false pressure measurements, it is also known from the document US-A1-7467544 to add redundancy to the brake booster pressure sensor. Below a certain drift threshold in the measurements taken by both sensors, a failure is reported. If such a process makes it possible to detect a failure of one of the pressure sensors, the very existence of such a failure risks impacting the braking capacity of the vehicle. The aim of the invention is to overcome the drawbacks of the prior art by proposing a method to secure the vehicle in the event of detection of a failure of a pressure sensor of a brake booster. In this context, the invention, in its broadest sense, relates to a method for controlling an electric traction machine of an electric or hybrid vehicle, said method comprising, when the vehicle is in motion, the steps, executed by vehicle control means, of: Detect a failure of at least one first pressure sensor or a second pressure sensor of a vehicle's brake booster, Determine a speed value for the vehicle, The process is remarkable in that it also includes the following steps: When a failure of at least one of the first or second pressure sensors is detected, determine a torque value to be applied to the vehicle's drive wheels, based on the determined speed value, to bring the vehicle to a predetermined safe speed. Apply the determined torque value to the drive wheels using the electric traction machine. Thanks to the process of the invention, when a failure of at least one pressure sensor of the brake booster is detected, the speed of the vehicle is brought to a predetermined safety speed, for example between 10 and 20 km/h so that the driver can stop the vehicle without brake assistance. In addition to the characteristics mentioned in the preceding paragraph, the process according to the invention may have one or more additional characteristics from among the following, considered individually or according to all technically possible combinations. US 2019/308598 A1 discloses a method for controlling an electric traction machine of an electric or hybrid vehicle. According to a non-limiting aspect of the invention, the method includes a step, executed by the control means, of displaying, on a vehicle display console, a vehicle stop indicator light. According to a non-limiting aspect of the invention, the method includes a step, executed by the control means, of displaying, on a vehicle display console, a message reflecting that a failure of at least one of the vehicle's first or second pressure sensor has been detected. According to a non-limiting aspect of the invention, the step of detecting a failure of at least one of the first or second pressure sensors comprises the following substeps: Receive an initial pressure measurement from the brake booster, determined by means of the first pressure sensor. Receive a second pressure measurement from the brake booster determined by means of the second pressure sensor, Determine the pressure difference between the first and second pressure measurements. Repeat, periodically according to a first determined period, the sub-steps of receiving a first pressure measurement, receiving a second pressure measurement and determining a pressure difference, If the determined pressure deviation is greater than a pressure threshold