METHOD FOR REGULATING A TANK CONNECTED TO A VEHICLE VACUUM PUMP

Abstract

The invention relates to a method for regulating a tank connected to a vehicle's vacuum pump. The method comprises pumping steps (E4, E5, E6) of the tank until a vacuum level equal to a first predetermined upper threshold value is reached, or a second predetermined upper threshold value when the vacuum level is lower than a first predetermined lower threshold value or a second predetermined lower threshold value, depending on the distance and approach of the vehicle to an obstacle. Figure 1

Description

Title of the invention: METHOD FOR REGULATING A TANK CONNECTED TO A VEHICLE VACUUM PUMP

[0001] The invention relates to a method of regulating vacuum pumping which improves the braking performance of a vehicle, in particular the emergency braking of the vehicle.

[0002] Utility certificate CN217864082U describes a system configured to issue a braking command to a vehicle, thereby activating a vacuum pump to operate the vehicle's brakes. The system includes a sensor configured to measure the distance between the vehicle and an obstacle. The system issues a braking command when the measured distance is less than a predetermined distance, thereby braking the vehicle.

[0003] However, in some cases of emergency braking when an obstacle is detected late, considering an available reserve of vacuum that is largely insufficient compared to a vacuum level required to brake the vehicle over a safe distance, the pumping time to reach this required vacuum level is not sufficient.

[0004] The objective of the present invention is to remedy these drawbacks and reduce the energy consumed by the vacuum pump.

[0005] To achieve this objective, the invention proposes a method for regulating a tank connected to a vacuum pump of a vehicle, the vehicle comprising: - a first sensor being configured to measure a distance between the vehicle and an obstacle; - a second sensor being configured to measure the vacuum level in the tank, the process comprising the following steps: - a step of measuring an initial distance between the vehicle and the obstacle by the first sensor, at a first instant; - a step of measuring a second distance between the vehicle and the obstacle by the first sensor, at a second instant, after a predetermined duration following the first instant; - a step of measuring a vacuum level value in the tank by the second sensor; - a step of pumping the tank by the vacuum pump until the measured vacuum level reaches a first predetermined upper threshold value when the first measured distance is greater than a predetermined distance and when the measured vacuum level is less than a first threshold value lower predetermined, the first upper threshold value being greater than the first lower predetermined threshold value; - a step of pumping the tank by the vacuum pump until the measured vacuum level value reaches the first predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the second measured distance is greater than the first measured distance and when the measured vacuum level value is less than the first predetermined lower threshold value; - a step of pumping the tank by the vacuum pump until the measured vacuum level value reaches a second predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the second measured distance is less than the first measured distance and when the measured vacuum level value is less than a second predetermined lower threshold value, the second predetermined upper threshold value being greater than the second predetermined lower threshold value.

[0006] Such a method makes it possible to maintain a vacuum level in the reservoir so that effective vehicle braking is guaranteed when an obstacle is detected. The method thus provided ensures safe braking over a stopping distance, particularly in emergency braking situations, while also helping to reduce the energy consumption of the vacuum pump by avoiding stressing the vacuum pump when the available vacuum level is already sufficient to achieve braking. Consequently, the method improves the vehicle's range while increasing the reliability of the vehicle's braking.

[0007] Advantageously, the second predetermined upper threshold value is greater than the first predetermined upper threshold value, the second predetermined lower threshold value being greater than the first predetermined lower threshold value.

[0008] Such predetermined lower threshold values ​​are chosen so that the vacuum level is maintained in the reservoir, thus preserving sufficient braking capacity to stop the vehicle approaching an obstacle while avoiding stressing the vacuum pump when the reservoir already contains a sufficient vacuum level to ensure safe braking. The predetermined upper threshold values ​​are chosen so that the vacuum level is sufficient for emergency braking situations and to prevent the vacuum pump from being stressed further when this level is reached.

[0009] Advantageously, the method further comprises: - a step to calculate a vehicle speed value, denoted v, using the following formula: v _ ^(where dl is the first measured distance, d2 is the second measured distance and T is the predetermined duration between the first instant and the second instant; - a step of pumping the tank by the vacuum pump until the measured vacuum level value reaches the second predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the calculated vehicle speed value is greater than a predetermined speed value.

[0010] The method allows the vacuum level to be adjusted in order to prepare for emergency braking according to the measured approach speed of the obstacle.

[0011] Advantageously, the predetermined speed value is between 100 m / s and 500 m / s.

[0012] Advantageously, the predetermined distance is less than 100 m.

[0013] Advantageously, the predetermined duration is between 500 ms and 1 s.

[0014] The invention also relates to a computer program comprising program code instructions for executing the steps of the process defined above, when said program is running on a computer.

[0015] The invention further relates to an assembly comprising an electronic control unit including acquisition means and processing means, by means of software instructions stored in a memory, as well as control means required for the implementation of the computer program defined as above.

[0016] The invention will be further detailed by describing a non-limiting embodiment, and based on the accompanying figure in which: - [Fig.1] illustrates a flowchart representing the steps of a process for regulating a tank connected to a vacuum pump of a vehicle, according to an embodiment of the invention.

[0017] According to the invention, a vehicle comprises a tank and a vacuum pump. The tank is connected to the vacuum pump. The connection between the tank and the vacuum pump has a seal preventing air leaks, thus ensuring that the vacuum is maintained constantly and reliably.

[0018] The vehicle also includes a first sensor and a second sensor described below.

[0019] The first sensor is configured to measure the distance between the vehicle and an obstacle. The first sensor is, for example, of the lidar, radar, ultrasound, or infrared type. It is mounted either, preferably, at the front of the vehicle, generally integrated into the grille or bumper, or at the rear of the vehicle, typically in the rear bumper. In principle, the first sensor emits a signal towards the obstacle and receives a signal reflected by the obstacle, allowing the distance between the vehicle and the obstacle to be calculated. Alternatively, the sensor is a camera.

[0020] The second sensor is configured to measure the vacuum level in the tank. The second sensor is located inside the tank. The second sensor is a pressure sensor. In principle, the second sensor measures the residual air pressure in the tank, the vacuum level being inversely proportional to the residual air pressure in the tank.

[0021] Figure [1] illustrates a flowchart of a method for regulating the tank connected to the vacuum pump of a vehicle, its steps being described below according to an embodiment of the invention.

[0022] In a measurement step El, a first distance between the vehicle and the obstacle is measured by the first sensor, at a first instant.

[0023] In a measurement step E2, a second distance between the vehicle and the obstacle is measured by the first sensor at a second instant, after a predetermined time following the first instant. Preferably, the predetermined time is between 500 ms and 1 s.

[0024] In a measurement step E3, a vacuum level value in the tank is measured by the second sensor. This measurement is carried out at a predetermined frequency.

[0025] In a pumping step E4, the vacuum pump pumps the tank until the measured vacuum level value reaches a first predetermined upper threshold value when the first measured distance is greater than a predetermined distance and when the measured vacuum level value is less than a first predetermined lower threshold value, the first upper threshold value being greater than the first predetermined lower threshold value.

[0026] In practice, the vacuum level value is measured at a given acquisition frequency, with the vacuum pump continuing to run as long as the measured vacuum level value is below the first predetermined upper threshold value.

[0027] In a pumping step E5, the vacuum pump pumps the tank until the measured vacuum level value reaches the first predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the second measured distance is greater than the first measured distance and when the measured vacuum level value is less than the first predetermined lower threshold value.

[0028] In a pumping step E6, the vacuum pump pumps the tank until the measured vacuum level value reaches a second predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the second measured distance is less than the first measured distance and when the measured vacuum level value is less than a second predetermined lower threshold value, the second predetermined upper threshold value being greater than the second predetermined lower threshold value.

[0029] Preferably, the predetermined distance is less than 100 m.

[0030] Preferably, the second predetermined upper threshold value is greater than the first predetermined upper threshold value, the second predetermined lower threshold value being greater than the first predetermined lower threshold value.

[0031] The process advantageously comprises the steps described below.

[0032] In a calculation step E7, a vehicle speed value, denoted v, is calculated using the following formula: v _ iî^l where d1 is the first measured distance, d2 is the second measured distance, and T is the predetermined time between the first and second instants. This calculation step E'7 is performed at a predetermined frequency.

[0033] In a pumping step E8, the vacuum pump pumps the tank until the measured vacuum level reaches the second predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the calculated vehicle speed is greater than a predetermined speed value. This pumping step E8 is performed, when its conditions are met, with priority over all the other aforementioned pumping steps.

[0034] Preferably, the predetermined speed is between 100 m / s and 500 m / s.

Claims

1. Demands Method for regulating a tank connected to a vacuum pump of a vehicle, the vehicle comprising: - a first sensor configured to measure the distance between the vehicle and an obstacle; - a second sensor configured to measure the vacuum level in the tank, The process includes the following steps: - a measurement step (El) of a first distance between the vehicle and the obstacle by the first sensor, at a first instant; - a measurement step (E2) of a second distance between the vehicle and the obstacle by the first sensor, at a second instant, after a predetermined duration following the first instant; - a measurement step (E3) of a vacuum level value in the tank by the second sensor; - a pumping step (E4) of the tank by the vacuum pump until the measured vacuum level value reaches a first predetermined upper threshold value when the first measured distance is greater than a predetermined distance and when the measured vacuum level value is less than a first predetermined lower threshold value, the first upper threshold value being greater than the first predetermined lower threshold value; - a pumping step (E5) of the tank by the vacuum pump until the measured vacuum level value reaches the first predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the second measured distance is greater than the first measured distance and when the measured vacuum level value is less than the first predetermined lower threshold value; - a pumping step (E6) of the tank by the vacuum pump until the measured vacuum level value reaches a second predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the second measured distance is less than the first measured distance and when the measured vacuum level value is less than a second predetermined lower threshold value, the second predetermined upper threshold value being greater than the second predetermined lower threshold value.

2. A method according to claim 1, characterized in that the second predetermined upper threshold value is greater than the first predetermined upper threshold value, the second predetermined lower threshold value being greater than the first predetermined lower threshold value.

3. A method according to claim 1 or 2, characterized in that the method further comprises: - a calculation step (E7) of a vehicle speed value, denoted v, by the following formula: v _ i^U where d1 is the first measured distance, d2 is the second measured distance and T is the predetermined time between the first instant and the second instant; - a pumping step (E8) of the tank by the vacuum pump until the measured vacuum level value reaches the second predetermined upper threshold value when the first measured distance is less than the predetermined distance and when the calculated vehicle speed value is greater than a predetermined speed value.

4. Method according to claim 3, characterized in that the predetermined speed value is between 100 m / s and 500 m / s.

5. A method according to any one of claims 1 to 4, characterized in that the predetermined distance is less than 100 m.

6. A method according to any one of claims 1 to 5, characterized in that the predetermined duration is between 500 ms and 1 s.

7. Computer program comprising program code instructions for carrying out the steps of the process according to any one of claims 1 to 6, when said program is running on a computer.

8. Assembly comprising an electronic control unit including acquisition means and processing means, by means of software instructions stored in memory, as well as control means required for the implementation of the computer program according to claim 7.