MOTOR VEHICLE COMPRISING A SYSTEM FOR MONITORING UNTIMELY ACCELERATION, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising a powertrain, an accelerator pedal, and a monitoring system which comprises: - a torque setpoint evaluation means evaluating a torque setpoint (C1) of the powertrain on the basis of a depression of said pedal; - a model (M) for calculating acceleration under reference conditions; - a means for calculating a reference speed uptake (VRF) on the basis of the torque setpoint (C1) and the calculation model (M) integrated during a detection time (TRF), - a means for evaluating an actual speed uptake (VRL) during the detection time (TRF), - a detection means detecting an untimely acceleration if the actual speed uptake (VRL) is greater than the reference speed uptake (VRF). The invention also relates to a method and a program based on such a vehicle. Figure 1

Description

Title of the invention: MOTOR VEHICLE COMPRISING A SYSTEM FOR MONITORING UNTIMELY ACCELERATION, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

[0001] The invention relates to the field of control and security systems for motor vehicles, and more particularly to the monitoring of untimely acceleration of said vehicle.

[0002] In the prior art, a torque monitoring function has been proposed characterized by a comparison between a secure setpoint torque, being an interpretation of the driver's wishes, and a torque actually achieved. If the torque achieved is greater than the setpoint torque, then a fault is declared.

[0003] The introduction of a new functionality that adapts the torque setpoint to the vehicle environment no longer makes it possible to calculate a secure torque setpoint. Indeed, in a system that is robust to variations in vehicle mass and slope variations, the driver's desire expressed in torque is transformed into the vehicle acceleration setpoint in a reference environment (in particular without slope, at minimum mass, and in running order).

[0004] This strategy involves torque variations to adapt the vehicle's reaction to its environment so that torque monitoring is no longer relevant. A regulation function adjusts the necessary torque so that the vehicle reaches the set acceleration regardless of the slope and the vehicle's mass.

[0005] The objective of the invention is to overcome the defects of the prior art, and in particular to propose a solution for interpreting the driver's desire for safe acceleration which is robust to the environment of the vehicle, in particular to detect untimely accelerations of the vehicle, in particular in a manner robust to the slope and mass of the vehicle.

[0006] To achieve this objective, the invention provides a motor vehicle comprising a powertrain, an accelerator pedal actuating the powertrain, and a monitoring system which comprises: - a means for evaluating a torque setpoint evaluating a torque setpoint of the powertrain on the basis of an amplitude of depression of the accelerator pedal; - an acceleration calculation model under reference conditions; - a means of calculating a reference speed setting on the basis of the torque setpoint and the calculation model integrated during a detection time, - a means of evaluating an actual speed increase during the detection time, - a detection means detecting an untimely acceleration if the actual speed increase is greater than the reference speed increase.

[0007] Advantageously, the invention makes it possible to take into account given reference conditions to determine the reference speed and deduce the desired speed therefrom. The monitoring system is therefore robust to said reference conditions.

[0008] According to a variant, the means for evaluating an actual speed increase measures the speed of the motor vehicle at the start of the detection time, and measures the speed of the motor vehicle at the end of the detection time to deduce therefrom the actual speed increase during the detection time.

[0009] This makes it possible to easily assess the actual speed gain.

[0010] According to a variant, the reference conditions comprise a zero rolling slope and a reference vehicle mass.

[0011] This allows for robustness to slope and mass.

[0012] According to a variant, the monitoring system further comprises a monitoring means activating a safe state when untimely acceleration is detected.

[0013] This makes it possible to secure the vehicle's behavior to protect its occupants and its external environment.

[0014] The invention further relates to a monitoring method for a motor vehicle according to the invention, comprising the following steps: - a step of evaluating a torque instruction; - a step of calculating a reference speed measurement on the basis of the torque setpoint and the calculation model integrated during a detection time, - a step of evaluating an actual speed increase during the detection time, - a detection step in which an untimely acceleration is detected if the actual speed increase is greater than the reference speed increase.

[0015] According to a variant, in the step of evaluating an actual speed increase, the speed of the motor vehicle is measured at the start of the detection time, and the speed of the motor vehicle is measured at the end of the detection time, to deduce therefrom the actual speed increase during the detection time.

[0016] According to a variant, the reference conditions comprise a zero rolling slope and a reference vehicle mass.

[0017] According to a variant, the monitoring method further comprises a monitoring step in which a safe state is activated when untimely acceleration is detected.

[0018] Another object of the invention relates to a computer program comprising program code instructions for executing the steps of the monitoring method according to the invention, when said program operates on a computer. A computer is generally understood to mean any programmable tool such as a calculator. It is specifically an electronic control unit (or "Electronic Control Unit" abbreviated "ECU").

[0019] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates a monitoring system according to the invention; and - [Fig.2] schematically illustrates the evolution over time of speeds, torques and accelerations within the framework of the invention.

[0020] The invention relates to a system for monitoring the acceleration of a motor vehicle with the aim of avoiding accelerations not controlled by the driver. The detection of untimely accelerations is carried out from the VRF speed information and reference acceleration A reflecting the driver's wishes.

[0021] To this end, the invention proposes functions for interpreting the driver's wishes which are robust to the vehicle's environment, in particular an acceleration of the vehicle which is robust to the slope and the mass of the vehicle. This involves adding an evaluation of a desired acceleration A; an integration of the desired acceleration A over a detection time Trf; and a detection criterion based on a measurement of the speed gain over the detection time TRF of the feared acceleration event.

[0022] Known technical solutions monitor the torque system. However, for them to work, there must be a bijective function between the inputs of the driver's will interpretation function (pedal depression and vehicle speed) and the torque produced by the powertrain.

[0023] The solution of the invention makes it possible to monitor the dreaded events (“untimely accelerations”) of a vehicle equipped with a function for interpreting the driver's desire for acceleration, robust to slope and mass.

[0024] The invention makes it possible, in a simple manner, to interpret the driver's wishes in order to evaluate a desired speed increase VRF averaged over an observed time interval Trf; and to compare the desired speed VRF with the speed increase V^. The invention makes it possible to monitor acceleration without having to observe the speed derivative (which can be difficult to measure).

[0025] More generally, the invention is integrated into the control of the powertrain and has the object of monitoring that the functions of interpreting the driver's wishes, the environmental compensations and the control of the powertrain components do not cause the feared event.

[0026] Now regarding the control of the powertrain, the function of interpreting the driver's will is robust to environmental variations. mental factors such as vehicle mass and slope. This function allows the same acceleration to be obtained regardless of the slope and vehicle mass for a given speed and accelerator pedal pressure.

[0027] The powertrain control monitoring function is as follows: - It begins with a calculation of the desired acceleration A secured from the interpretation of the driver's wishes (via a torque instruction Cl) in reference conditions, i.e. without slope (zero slope) and at reference mass (in running order); - Then a calculation of the theoretical speed P (reference Vrf) is carried out by integration i of the desired acceleration A over the detection time Trf; - then a measurement of the speed uptake is carried out over the TRF detection time; - finally, a deviation is detected between the actual speed reading Vrl and the reference speed reading Vrf.

[0028] In particular, the driver's will is expressed in wheel torque (Cl); and the acceleration is expressed by: Wheel radius *C1 reference mass

[0029] The reference mass is for example the mass of the vehicle in running order, that is to say the minimum mass of the vehicle in motion (for example 1600 kg). This is the mass of the vehicle that the system will consider. It is with this mass that we define what acceleration the vehicle will theoretically reach with the torque requested by the vehicle.

[0030] The mass we take as an example is the mass in running order. It corresponds to the minimum mass of the vehicle in motion (it is defined by the minimum fluid necessary for the operation of the vehicle and a driver).

[0031] The integration i is in particular a control command function carried out by a computer (ECU). The acceleration A is digitally integrated over the time interval TRF to give the speed difference (called "speed uptake") over the same time interval TRF.

[0032] The calculation of the desired acceleration A (reference) is done by means of a vehicle dynamics model M using the reference vehicle characteristics.

[0033] The calculation of the reference speed Vrf is done by integration i over the detection time TRF.

[0034] The calculation of the real speed VRL is done by measuring the speed of the vehicle at a time (LTrf) i.e. just before the detection time TRF; then at time t i.e. at the end of the detection time Trf.

[0035] The actual speed reading Vrl and the reference speed reading P Vrf are compared. Then, according to given criteria of untimely acceleration, a safe state S can be activated. In particular, we can consider that there is an untimely acceleration if the actual speed uptake VRL is greater than the reference speed uptake Vrf.

[0036] In the event of detection of untimely acceleration, the torque is safely cut off and the computer is reset.

[0037] In [Fig.2], Ci represents the torque in the case of the invention, Caa is that of the prior art.

[0038] The invention further relates to a corresponding monitoring method and program. The program can be loaded into a controller of the motor vehicle.

Claims

Claims

1. A motor vehicle comprising a powertrain, an accelerator pedal actuating the powertrain, and a monitoring system which comprises: - a torque setpoint evaluation means evaluating a torque setpoint (Cl) of the powertrain on the basis of an amplitude of depression of the accelerator pedal; - a model (M) for calculating acceleration under reference conditions;- a means for calculating a reference speed (Vrf) take-up (P) on the basis of the torque setpoint (Cl) and the calculation model (M) integrated during a detection time (TRF), - a means for evaluating a real speed (VRL) take-up (P) during the detection time (T^), - a detection means detecting an untimely acceleration if the real speed (VRL) take-up is greater than the reference speed (Vrf), characterized in that the means for evaluating a real speed (Vrl) take-up measures the speed of the motor vehicle at the start of the detection time (TRF), and measures the speed of the motor vehicle at the end of the detection time (T^) to deduce therefrom the real speed (VRL) take-up during the detection time (T^), the model (M) being a vehicle dynamics model.;

2. Motor vehicle according to claim 1, characterized in that the reference conditions comprise a zero rolling gradient and a reference vehicle mass.

3. Motor vehicle according to any one of claims 1 to 2, characterized in that the monitoring system further comprises monitoring means activating a safe state (S) when untimely acceleration is detected.

4. Monitoring method for a motor vehicle according to any one of claims 1 to 3, comprising the following steps: - a step of evaluating a torque setpoint (Cl); - a step of calculating a reference speed uptake (Vrf) on the basis of the torque setpoint (Cl) and the calculation model (M) integrated during a detection time (TRF), - a step of evaluating an actual speed uptake (VRL) during the detection time (TRF), - a detection step in which an untimely acceleration is detected if the actual speed uptake (Vrl) is greater than the reference speed uptake (Vrf).

5. Monitoring method according to claim 4, characterized in that in the step of evaluating an actual speed increase (VRL), the speed of the motor vehicle is measured at the start of the detection time (Trf), and the speed of the motor vehicle is measured at the end of the detection time (Trf), to deduce therefrom the actual speed increase (Vrl) during the detection time (Trf).

6. Monitoring method according to any one of claims 4 to 5, characterized in that the reference conditions comprise a zero rolling slope and a reference vehicle mass.

7. Monitoring method according to any one of claims 4 to 6, characterized in that it further comprises a monitoring step in which a safe state is activated when untimely acceleration is detected.

8. A computer program comprising program code instructions for carrying out the steps of the monitoring method according to any one of claims 4 to 7, when said program is running on a computer.

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