method for adapting driving parameters including an accurate estimation of the vehicle's mass

Abstract

The invention relates to a method of adapting parameters governing the dynamic behavior of a vehicle (1), as a function of the mass of the vehicle (1) obtained from a measurement of the ground clearance (x1, x2), said method being carried out with an on-board computer having as input data the mass of the vehicle (1).According to the invention, the method comprises: - during vehicle setup: a step establishing a correlation between the vehicle's ground clearance (x1, x2) and the vehicle's mass; a step repeating the previous step for at least one other value of the outside temperature; and a step developing a map establishing a correlation between the ground clearance (x1, x2) and the vehicle's mass (1) for different outside temperatures; - then, during vehicle operation, a step adapting the parameters governing the vehicle's dynamic behavior (1) according to the vehicle's mass (1) deduced from the measured outside temperature. Figure 4 for the abstract.

Description

Title of the invention: method for adapting driving parameters comprising an accurate estimation of the mass of the vehicle

[0001] The present invention relates to a method for adapting driving parameters comprising an accurate estimation of the mass of the vehicle.

[0002] For example, during a vehicle's driving phase, the acceleration and deceleration phases controlled by the driver will be directly dependent on the vehicle's mass. Indeed, if no adjustments are made to the vehicle's calibration, for the same application of the accelerator pedal, the acceleration phases will be more pronounced if the vehicle is light and less so if it is heavier. However, for a driver to experience the same level of comfort, it is desirable that the vehicle's response be the same, for example, when the accelerator pedal is pressed, regardless of the vehicle's mass. As mentioned above, the phenomenon of a difference in vehicle response depending on its mass is also observed during vehicle deceleration phases.

[0003] In other words, by way of example, the depressment of the accelerator pedal is interpreted as a desire by the driver to accelerate, and determines, according to the engine speed, a setpoint for engine torque which makes it possible to obtain this acceleration, because according to the fundamental principle of dynamics, the product of the mass by the acceleration is equal to the engine effort at the wheel, which is proportional to the engine torque, reduced by the resisting forces.

[0004] The value of the torque is generally determined in order to obtain an acceleration for a vehicle having a given reference mass and on a flat road.

[0005] However, if the mass is different, the acceleration is not the same.

[0006] Publication FR3075735 proposes a method for adapting the torque setting according to the vehicle's mass. More specifically, this method makes it possible to determine, for the same accelerator pedal depress, a different torque setting depending on the vehicle's mass, which compensates for the difference in load. In this way, the driver will have the same sensation of acceleration, regardless of the vehicle's mass, at least over a portion of the pedal's operating range.

[0007] Publication US2020 / 0055521A1 discloses the principle of estimating the mass of a vehicle from ride height sensors corresponding to the vehicle's ground clearance. In one example, the vehicle is equipped with four sensors at each wheel end. In such an approach, the relationship between the Ride height and mass depend on the suspension geometry and / or the properties of suspension components, such as springs. In one example, a polynomial relationship is determined between ride height and mass. This publication reveals that the principle of the relationship between vehicle mass and ground clearance measured by one or more sensors is known. However, in this patent application, the vehicle mass estimate is rudimentary because it does not take into account certain parameters that can directly influence this estimate. It therefore lacks precision.

[0008] A method according to the invention makes it possible to adapt the vehicle's driving parameters based on a very precise estimate of the vehicle's mass, taking into account other parameters that can directly impact the mass estimate. The more rigorous and precise the vehicle mass estimate, the more precise the adaptation of the parameters governing the vehicle's dynamic behavior will be. The driver will then have the impression that the vehicle's response will be constant, regardless of its mass, whether, for example, during acceleration, deceleration, or at idle.

[0009] The invention relates to a method of adapting parameters governing the dynamic behavior of a vehicle, as a function of the mass of the vehicle obtained from a ground clearance measurement made with at least one distance sensor, said method being managed by means of an on-board computer having as input data the mass of the vehicle.

[0010] According to the invention, the method comprises: - during vehicle development, a step to establish a correspondence between the measurement of the vehicle's ground clearance and the vehicle's mass for a given outside temperature, said step being carried out from at least two measurement points of said ground clearance for two different vehicle masses, the other vehicle masses being deduced by linear interpolation, -a step repeating the previous step for at least one other value of the outside temperature; and, -a step of developing a map establishing a correspondence between the ground clearance measurement by said at least one sensor and the mass of the vehicle, for different outside temperatures, - then during the vehicle's movement, an adaptation step by the computer, of the parameters governing the dynamic behavior of the vehicle as a function of the vehicle's mass deduced from the measured outside temperature, so that the vehicle's behavior remains unchanged for the driver, regardless of the vehicle's mass determined.

[0011] A method according to the invention aims to determine as precisely as The vehicle's mass can be adjusted, taking into account the outside temperature, so that the onboard computer can adapt the parameters governing the vehicle's dynamic behavior as precisely as possible. In this way, whether the vehicle is empty or fully loaded, the driver experiences the same driving sensation when, for example, pressing the accelerator pedal. Indeed, to give a basic example, for the same application of the accelerator pedal by the driver, a heavy vehicle will experience slower acceleration, while a lighter vehicle will experience greater acceleration. A method according to the invention aims to eliminate these differences in acceleration so that the driver experiences the same acceleration, whether the vehicle is empty or more or less loaded. The method results in the creation of a map linking three parameters: the vehicle's ground clearance, its mass, and the outside temperature.By incorporating outside temperature into this mapping process, determining the vehicle's mass becomes more precise, reliable, and safe. The outside temperature is continuously measured by a temperature sensor installed in the vehicle. To obtain a comprehensive map, the correlation between ground clearance and vehicle mass is determined for several outside temperatures. For a given temperature, the correlation between vehicle ground clearance and mass is established for different vehicle masses. Parameters governing the vehicle's dynamic behavior can include, for example, torque or power demands.

[0012] According to one possible feature of the invention, the step of developing the mapping that establishes a correspondence between the vehicle's ground clearance measurement and the vehicle's mass for a given outside temperature is carried out using two ground clearance measurement points for two different vehicle masses: one corresponding to the vehicle's unladen mass and the other to the vehicle's mass when fully loaded. In this way, the two correspondence points, as far apart as possible, are obtained. It is then sufficient to draw a straight line connecting these two extreme points to deduce the other correspondence points located between them. Each vehicle manufacturer, in conjunction with the legislator, defines a maximum load for a given vehicle model, beyond which it is prohibited to load the vehicle.

[0013] According to one possible feature of the invention, the various measurements of the vehicle's ground clearance are taken with a single distance sensor, which is placed between the center of the vehicle and its rear. In this way, the sensor measurement will be highly representative of the mass of the passengers and the cargo in the trunk.

[0014] According to one possible feature of the invention, the distance sensor is a radar-type sensor.

[0015] According to one possible feature of the invention, the various measurements of the vehicle's ground clearance are taken using several distance sensors that are equally distributed between the front and rear of the vehicle. The vehicle's mass is estimated using the average of the ground clearances measured by said sensors. Taking into account the average of the ground clearances measured by the sensors makes it possible to eliminate minor measurement inconsistencies between said sensors and to determine a ground clearance value.

[0016] According to a possible feature of the invention, the vehicle ground clearance measurements by said at least one sensor are carried out, on the one hand with a vehicle for which the engine is off, and on the other hand, with the same vehicle for which the engine is running, said vehicle ground clearance measurements being carried out at a minimum with the front doors and the rear doors closed.

[0017] According to one possible feature of the invention, the method comprises, at each visit to the dealership for vehicle maintenance, the following steps: -a step involving positioning the vehicle in an empty configuration, -a step of estimating the mass of the unladen vehicle from a measurement of the ground clearance of said vehicle by said at least one distance sensor, at the handling temperature, -a comparison step between the vehicle mass estimated in the previous step and that obtained from a map established at the origin of said vehicle, without the latter having undergone any aging, -if a difference is observed between the two masses during the previous step, a step of applying said difference to the entirety of the initial mapping.

[0018] Since a method according to the invention is intended to determine the vehicle's mass as precisely as possible at a given moment, it will take into account, during this determination, not only the outside temperature but also the aging of certain vehicle components that may play a role in said determination. A mapping of the correlation between the vehicle's ground clearance and its mass was initially carried out at ambient temperature, when the vehicle was new and had not yet been driven. When the vehicle is due for servicing at a dealership, after having already been driven, it is emptied of all load, and then the vehicle's ground clearance is measured for the empty vehicle. This ground clearance is then compared to that obtained from the mapping carried out for the new vehicle.If a discrepancy is observed between these two ground clearance measurements, this discrepancy is systematically applied to all other points on the map. A new map, taking into account the vehicle's age, is then created, and this new map will be used for the next step. the adaptation of parameters governing the dynamic behavior of the vehicle.

[0019] According to one possible feature of the invention, the observed discrepancy reveals the aging of certain components governing the estimation of the vehicle's mass, including the vehicle's suspension, tires, and ground clearance sensors. A method according to the invention, in addition to adapting the parameters governing the vehicle's dynamic behavior based on its mass, also reveals the aging of certain vehicle parts.

[0020] According to a possible feature of the invention, the step of adapting by the computer the parameters governing the dynamic behavior of the vehicle consists of adapting the accelerator pedal mapping to the estimated mass of the vehicle, so that for a given depressment of the accelerator pedal, the acceleration of the vehicle is constant regardless of the mass of the vehicle.

[0021] According to one possible feature of the invention, the step in which the computer adapts the parameters governing the vehicle's dynamic behavior consists of providing the driver with additional torque and / or power if the vehicle's mass is high, during certain phases of vehicle operation. For example, if the vehicle is stopped on a slope and the driver has to start uphill, the computer can add torque or power if the vehicle is loaded, to compensate for the vehicle's weight.

[0022] A detailed description of a preferred embodiment of an adaptation method according to the invention is given below, with reference to the following figures:

[0023] [Fig-1] is a schematic side view of an empty vehicle,

[0024] [Fig.2] is a schematic side view of the vehicle of the [Fig.1] loaded at its maximum,

[0025] [Fig.3] is a diagram showing the proportionality between the mass of the vehicle and its ground clearance,

[0026] [Fig.4] is a diagram of an example of acceleration as a function of the accelerator pedal position, when the vehicle is fully loaded and without adaptation, when the vehicle has only one person on board, and when the acceleration is adapted according to the actual mass carried,

[0027] [Fig.5] is a diagram of an example of deceleration as a function of speed, when the vehicle is empty and when the vehicle has an increased mass, said diagram showing the deceleration gap to be filled.

[0028] With reference to Figures 1 and 2, the mass of a vehicle 1 is determined from a measurement of the vehicle's ground clearance. The ground clearance of a vehicle 1 is the distance between the underside of the vehicle and the ground on which it is placed. From this Thus, when vehicle 1 is light, as illustrated in [Fig. 1], the measured ground clearance takes a first value, xl. When vehicle 1 is heavier, as illustrated in [Fig. 2], the ground clearance takes a second value, x2, which is less than the first value, xl. In this way, for a given outside temperature, it is simple to establish a correlation between the vehicle's ground clearance and its mass. This correlation is established using two measurement points, for example, when vehicle 1 is light and carries only one person, and when vehicle 1 is fully loaded. A straight line is drawn between these two measurement points, and other correlation points are deduced by linear interpolation on this line. This correlation between the vehicle's ground clearance and its mass for a given outside temperature is programmed into the vehicle's onboard computer.In this way, during a vehicle's driving phase, the computer, which receives the vehicle's mass as input data at every moment of that driving phase, can instantly adapt the parameters governing the vehicle's dynamic behavior based on the vehicle's mass deduced from the ground clearance measurements. Therefore, the more precise the determination of the vehicle's mass, the more accurately the computer can adapt the parameters governing the vehicle's dynamic behavior, so that the driver feels no difference, whether the vehicle is empty or fully loaded.

[0029] A method according to the invention includes a step of determining the mass of the vehicle as precisely as possible, taking into account two parameters that can strongly influence this determination: -the outside temperature, -the aging of certain vehicle parts, such as suspension components.

[0030] With regard to taking into account the outside temperature, a method according to the invention comprises the following steps: -with reference to [Fig. 3], a step of establishing a correspondence between the vehicle's ground clearance measurement and the vehicle's mass for a given outside temperature, said step being carried out from at least two ground clearance measurement points 2, 3 for two different vehicle masses, the other vehicle masses being deduced by linear interpolation. The two different vehicle masses from which the measurements are taken could, for example, correspond to an empty vehicle and a vehicle fully loaded. The maximum load that can be placed in a vehicle is given by the vehicle manufacturer in conjunction with the legislator, and therefore cannot exceed a threshold value. A straight line 4 is drawn between the two measurement points 2, 3, and the other correspondence points are deduced by linear interpolation from this line 4. The measurement of The vehicle's ground clearance can be measured using a single distance sensor placed between the center and rear of the vehicle to account for the presence of passengers. Alternatively, it can be measured using four distance sensors distributed across the four corners of the vehicle, in which case the average of these four measurements is used. Furthermore, the vehicle's ground clearance measurements using at least one sensor are taken with the engine off and then again with the engine running. These ground clearance measurements are taken with at least the front and rear doors closed. This is because a vehicle in use, whether moving or stationary, typically has its doors closed.

[0031] - a step repeating the previous step for different values ​​of the outside temperature. The present step can, for example, be carried out with an outside temperature varying from -20°C to 40°C, and every 5°, - a step involving the development of a map establishing a correlation between the ground clearance measurement by at least one sensor and the vehicle's mass, for different outside temperatures. This map establishes a relationship between the following three parameters: the vehicle's ground clearance, the outside temperature, and the vehicle's mass. This map is programmed into the engine control unit (ECU). - An adaptation step by the computer, adjusting the parameters governing the vehicle's dynamic behavior based on the vehicle's mass, deduced from the measured outside temperature, ensures that the vehicle's behavior remains unchanged for the driver, regardless of the vehicle's mass. The outside temperature, measured in real time during a driving phase, serves as input data for the computer, which can then fine-tune the parameters regulating the vehicle's dynamic behavior. In this way, the driver will have the impression that their vehicle always responds in the same way, for example, when pressing the accelerator pedal, regardless of the vehicle's mass, or during a deceleration phase.

[0032] With regard to taking aging into account, a method according to the invention comprises, at each visit to the dealership for vehicle maintenance, the following steps: -a step involving positioning the vehicle in an empty configuration, -a step of estimating the mass of the unladen vehicle from a measurement of the ground clearance of said vehicle by said at least one distance sensor, at the handling temperature, -a comparison step between the vehicle mass estimated during the step previous and that resulting from a map established at the origin of said vehicle, without the latter having undergone any aging, -if a difference is observed between the two masses during the previous step, a step of applying said difference to the entirety of the mapping initially carried out when the vehicle was new.

[0033] In this way, during each subsequent visit to the dealership for servicing or maintenance, the vehicle's ground clearance is measured again, notably to verify that there has been no drift over time that would alter this ground clearance. The vehicle is thus placed under standard conditions, in this case in an unladen configuration, and its ground clearance is then measured before being compared to the ground clearance of the same vehicle, established when it was new and also unladen. This comparison is performed at the same outside temperature. If no difference in ground clearance is detected, this means that the vehicle's aging has had no impact on the ground clearance measurement. Conversely, if a difference is observed between the two ground clearance values, then this difference is recorded on all points of the initial mapping created when the vehicle was new.

[0034] These different steps make it possible to reveal the aging of certain parts of the vehicle, such as for example the tires, the suspensions or the distance measurement sensors.

[0035] Once the mass of the vehicle is determined precisely, taking into account the outside temperature and the aging of certain parts, certain parameters governing the dynamic behavior of the vehicle are adapted, so that the driver feels that his vehicle always behaves in the same way, regardless of its mass.

[0036] The possible adaptations of the powertrain to the dynamic behavior of the vehicle are as follows: • Provision of additional torque and / or engine power for a limited period, for example in the case of starting on an incline, • Creation of a map of accelerator pedal depressor depth as a function of estimated mass, o Referring to [Fig. 4], the powertrain's response to driver input, corresponding to a specific accelerator position, can be adjusted according to the vehicle's mass. Indeed, without this adjustment, and for a loaded vehicle as illustrated in curve 5, the vehicle's acceleration will be low compared to that of the same vehicle with only one person on board, as illustrated in curve 6. Therefore, with this invention, the effect of mass can be corrected by increasing the powertrain's torque to achieve a more accurate representation. of the powertrain response with 1 or 2 people on board, as illustrated by intermediate curve 7. • Referring to [Fig. 5], adaptation of so-called "regenerative" braking on vehicles equipped with an electric battery, in order to ensure a constant level of deceleration when the accelerator is released, regardless of the vehicle's mass. Curve 8 illustrates the vehicle's deceleration when empty, and curve 9 illustrates the vehicle's deceleration when loaded. Arrow 10 illustrates an adaptation of the electric battery's regenerative braking level to compensate for the difference in deceleration. • Adaptation of the force to the wheels in order to maintain a level of creep (corresponding to the residual speed of the vehicle when the foot is lifted) in constant speed, regardless of the mass. • Dashboard alert in case of vehicle overload, when it exceeds a permitted threshold value. • Adaptation of vehicle restraint strategies at zero speed, etc.

Claims

Claims

1. Method for adapting parameters governing the dynamic behavior of a vehicle (1), as a function of the mass of the vehicle (1) obtained from a measurement of the ground clearance (xl, x2) carried out with at least one distance sensor, said method being managed by means of an on-board computer having as input data the mass of the vehicle (1), characterized in that it comprises: - during the development of the vehicle: a step of establishing a correspondence between the measurement of the ground clearance (xl, x2) of the vehicle and the mass of the vehicle for a given outside temperature value, said step being carried out from at least two measurement points of said ground clearance (xl, x2) for two different masses of the vehicle (1), the other masses of the vehicle (1) being deduced by linear interpolation, - a step of repeating the previous step for at least one other value of the outside temperature,- a step of developing a map establishing a correspondence between the measurement of the ground clearance (xl, x2) by said at least one sensor and the mass of the vehicle (1), for different exterior temperatures, - then when the vehicle is running, a step of adaptation by the computer, of the parameters governing the dynamic behavior of the vehicle (1) as a function of the mass of the vehicle (1) deduced from the measured exterior temperature, so that the behavior of the vehicle (1) remains unchanged for the driver, whatever the mass of the vehicle (1) determined.,

2. Adaptation method according to claim 1, characterized in that the step of developing the mapping establishing a correspondence between the measurement of the ground clearance (xl, x2) of the vehicle (1) and the mass of the vehicle (1) for a given external temperature value, is carried out from two measurement points of said ground clearance (xl, x2) for two different masses of the vehicle (1), one corresponding to the mass of the vehicle (1) empty and the other corresponding to the mass of the vehicle (1) loaded to its maximum.

3. Adaptation method according to any one of claims 1 or 2, characterized in that the different measurements of the ground clearance (xl, x2) of the vehicle are carried out with a single distance sensor, which is placed between the center of the vehicle (1) and the rear of the vehicle.

4. Adaptation method according to claim 3, characterized in that the distance sensor is a radar type sensor.

5. Adaptation method according to any one of claims 1 or 2, characterized in that the different measurements of the ground clearance (xl, x2) of the vehicle (1) are carried out by means of several distance sensors which are equally distributed between the front and the rear of the vehicle (1), and in that the estimation of the mass of the vehicle (1) is carried out using the average of the ground clearances (xl, x2) measured by said sensors.

6. Adaptation method according to any one of claims 1 to 5, characterized in that the measurements of the ground clearances (xl, x2) of the vehicle (1) by said at least one sensor are carried out, on the one hand with a vehicle (1) for which the engine is stopped, and on the other hand, with the same vehicle (1) for which the engine is running, and in that said measurements of the ground clearances (xl, x2) of the vehicle (1) are carried out at least with the front doors and the rear doors closed.

7. Adaptation method according to any one of claims 1 to 7, characterized in that it comprises, at each visit to the dealership for maintenance of the vehicle (1), the following steps: - a step of placing the vehicle (1) in an unladen configuration, - a step of estimating the mass of the vehicle (1) unladen from a measurement of the ground clearance (xl, x2) of said vehicle (1) by said at least one distance sensor, at the handling temperature, - a step of comparing the mass of the vehicle (1) estimated during the previous step and that resulting from a map originally established for said vehicle (1), without the latter having undergone the slightest aging, - if a difference is observed between the two masses during the previous step, a step of applying said difference to the entire initial map.

8. Adaptation method according to claim 7, characterized in that the observed difference in elements makes it possible to reveal a state of aging of certain elements governing the estimation of the mass of the vehicle (1), including the suspensions of the vehicle (1), the tires, and the ground clearance measurement sensors (xl, x2) of the vehicle (1).

9. Adaptation method according to any one of claims 1 to 8, characterized in that the step of adaptation by the computer of the parameters governing the dynamics of the vehicle (1) consists of adapting the mapping the accelerator pedal to the estimated mass of the vehicle (1), such that, for a given depression of the accelerator pedal, the acceleration of the vehicle is constant regardless of the mass of the vehicle.

10. Adaptation method according to any one of claims 1 to 8, characterized in that the step of adaptation by the computer of the parameters governing the dynamic behavior of the vehicle consists of making additional torque and / or power available to the driver if the mass of the vehicle (1) was high during certain driving phases of the vehicle (1).

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