ESTIMATING THE CURRENT MASS OF A LAND VEHICLE IN THE PRESENCE OF ROAD LAWS

Abstract

A process is implemented in a vehicle that stores driving laws associated with predefined masses as a function of the current speed, and provides an effective power. This process includes a step (10-50) in which, when the vehicle has a constant speed, an effective power is estimated using one of the driving laws for that speed. Then, a difference is determined between the estimated and provided effective powers. When this difference is less than a threshold, the predefined mass associated with that driving law is chosen as the current mass. Otherwise, at least one other effective power estimate is performed using another driving law for that speed, and another difference determination is made until a difference less than the threshold is obtained, at which point the predefined mass associated with the corresponding driving law is chosen as the current mass. Figure 3

Description

Title of the invention: ESTIMATION OF THE CURRENT MASS OF A LAND VEHICLE IN THE PRESENCE OF LAWS OF ROAD Technical field of the invention

[0001] The invention relates to land vehicles, and more specifically to the estimation of the current mass of such vehicles when they are moving. State of the art

[0002] Certain land vehicles, possibly of the automobile type, include a powertrain (or GMP) capable of providing their drive wheels with effective power.

[0003] It will be noted that the invention relates to all types of GMP, whether purely thermal, purely electric or hybrid (thermal and electric). Furthermore, when the GMP comprises at least one electric motor, the latter can produce its output torque from the electrical energy supplied by an electrical energy source in the form of a main (or traction) battery or a fuel cell.

[0004] As is known to those skilled in the art, knowledge of the current mass of a land vehicle can have at least two uses.

[0005] A first use concerns the starts (or "takeoffs") of the (land) vehicle when it is located on a sloping traffic lane. Indeed, the on-board computer which manages slope starts generally uses a theoretical mass of the vehicle which is equal to an average value (between its empty mass and its towable mass), and therefore it frequently happens that the vehicle is subject to jolts when its current mass is significantly different from the theoretical mass used.

[0006] A second use concerns the vehicle checks carried out by certain authorities to compare their actual consumption with their theoretical consumption (announced by their manufacturer) and / or their actual mileage range with their theoretical mileage range (announced by their manufacturer). It will be understood that the actual consumption and the actual mileage range of a vehicle can vary significantly depending on its current mass.

[0007] It has already been proposed, in particular in patent document FR-B1 2857090, to estimate the current mass of a moving vehicle. This estimation is carried out in an acceleration phase of the vehicle, and consists of multiplying a first mass (which may be the empty mass of the vehicle, for example) by the measured acceleration of the vehicle to determine a first torque for the drive wheels, then to compare this first determined torque with a second torque which has actually been supplied to the drive wheels (and which is equal to the engine torque less the inertial torque dissipated by the transmission chain). Then, the difference between the first and second torques is used to converge the mass of the vehicle to a current mass by means of the least squares technique (or a rule of three).

[0008] A main disadvantage of this estimation method is that it uses a formula that does not take into account either the rolling force, which depends on the speed and current mass of the vehicle, or the aerodynamic force, because they are unstable under acceleration. Therefore, the estimated current mass is very inaccurate.

[0009] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0010] It proposes in particular for this purpose an estimation method intended to be implemented in a vehicle to estimate its current mass, this vehicle being terrestrial, comprising a powertrain capable of supplying effective power to the drive wheels, and storing road laws respectively representative of effective powers, associated respectively with predefined masses and depending on a current speed of the vehicle.

[0011] This estimation method is characterized by the fact that it comprises a step in which, when the vehicle has a constant current speed, an effective power is estimated with one of the road laws for the current speed, then a difference is determined between the estimated and supplied effective powers, and when this difference is less than or equal to a chosen threshold, the predefined mass associated with this road law is chosen as the current mass, while when this difference is greater than said chosen threshold, at least one other estimate of effective power is carried out with another of the road laws for the current speed and another determination of difference until a difference less than or equal to the chosen threshold is obtained and the predefined mass associated with the corresponding road law is chosen as the current mass.

[0012] Thanks to the invention, a fairly precise current mass is now available because it results from calculations taking into account the rolling force and the aerodynamic force when the current speed is stabilized (or constant), which makes it possible, in particular, to improve the management of the vehicle's starts (or take-offs) on slopes and to make the results of vehicle checks carried out by an authority reliable and precise in order to compare its actual consumption with its theoretical consumption and / or its actual mileage autonomy with its theoretical mileage autonomy.

[0013] The estimation method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0014] - in its step, we can carry out each estimation when the vehicle has a constant running speed for a duration at least equal to a predefined value;

[0015] - in the presence of the first option, in its step, the predefined value can be between 500 ms and 2 s;

[0016] - in its step, each road law associated with a predefined mass can be defined by a formula ((F0 + Fl*vv + F2*vv2) + (mpn*g*pp))*vv / 3600, where vv is the current speed, mpn is the predefined mass, g is an acceleration of Earth gravity, pp is a percentage of slope of a traffic lane on which the vehicle is traveling, and F0, Fl and F2 are coefficients associated with this predefined mass mpn;

[0017] - in the presence of the last option, in its step, each effective power estimated with a road law can be equal to the value taken by the formula ((F0 + Fl*vv + F2*vv2) + (mpn*g*pp))*vv / 3600 of this road law for the current speed;

[0018] - in its step, the threshold can be between 20 kg and 80 kg;

[0019] - in its step, the road laws can be respectively associated with at least three predefined masses chosen from a so-called unladen mass of the vehicle, a so-called half-payload mass of the vehicle, a so-called payload mass of the vehicle, a total laden mass of the vehicle, and a total towable mass of the vehicle.

[0020] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing an estimation method of the type presented above, in a land vehicle, comprising a powertrain capable of supplying drive wheels with effective power, and storing road laws respectively representative of effective powers, associated respectively with predefined masses and depending on a current speed of the vehicle, and comprising a powertrain capable of supplying drive wheels with effective power, to estimate a current mass of the vehicle.

[0021] The invention also proposes an estimation device intended to equip a land vehicle, comprising a powertrain suitable for supplying drive wheels with effective power, and storing road laws respectively representative of effective powers, associated respectively with predefined masses and depending on a current speed of the vehicle.

[0022] This estimation device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting, when the vehicle has a constant current speed, in estimating an effective power with one of the road laws for the current speed, then in determining a difference between the estimated and supplied effective powers, and, when this difference is in less than or equal to a chosen threshold, to choose the predefined mass associated with this road law as the current mass, while when this difference is greater than the chosen threshold, to carry out at least one other estimate of effective power with another of the road laws for the current speed and another determination of difference until obtaining a difference less than or equal to the chosen threshold and choice of the predefined mass associated with the corresponding road law as the current mass.

[0023] The invention also proposes a land vehicle, possibly of the automobile type, comprising an estimation device of the type presented above and a powertrain suitable for providing drive wheels with effective power, and storing road laws respectively representative of effective powers, associated respectively with predefined masses and depending on a current speed of the vehicle. Brief description of the figures

[0024] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0025] [Fig-1] schematically and functionally illustrates an example of the embodiment of a vehicle comprising an electric GMP associated with a supervision computer, and an estimation device according to the invention,

[0026] [Fig.2] schematically and functionally illustrates an example of the embodiment of a supervision calculator comprising an exemplary embodiment of an estimation device according to the invention, and

[0027] [Fig.3] schematically illustrates an example of an algorithm implementing a estimation method according to the invention. Detailed description of the invention

[0028] The invention aims in particular to propose an estimation method, and an associated estimation device DE, intended to allow an estimation of the current mass mcv of a land vehicle V.

[0029] In the following, it is considered, by way of non-limiting example, that the land vehicle V is of the automobile type. It is for example a car, as illustrated in [Fig.l]. But the invention is not limited to this type of land vehicle. It relates in fact to any type of land vehicle storing road laws and comprising a powertrain (or GMP) capable of providing effective power to the drive wheels. Thus, it also relates, for example, to utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), and tracked vehicles.

[0030] Furthermore, it is considered in the following, by way of non-limiting example, that the land vehicle V includes a powertrain (or GMP) of the all-electric type (and therefore whose drive is provided exclusively by at least one electric motor MME). But the GMP could be of the hybrid type (thermal and electric) or of the purely thermal type.

[0031] Furthermore, it is considered in the following, by way of non-limiting example, that the electric motor MME is supplied with electrical energy by a main (or traction) battery BP, rechargeable during recharging phases. But the electric motor MME could be supplied with electrical energy by a fuel cell.

[0032] [Fig.l] schematically shows a (land) vehicle V comprising a transmission chain with electric GMP (and therefore with electric motor MME), an on-board network RB, a service battery BS, a main (or traction) battery BP, a converter CV, a supervision computer CS, and an estimation device DE according to the invention.

[0033] It will be noted that the vehicle V also comprises, here, a DCT trajectory control device of the ESP / ABS type (ESP: “Electronic Stability Program”), ABS: “Anti-Blocking System”)), and in particular responsible for estimating the current speed vv of the vehicle V from information provided by a sensor associated with one of the drive wheels of the vehicle V. In fact, this sensor can be coupled to a wheel hub and can constitute an angular encoder determining a number of teeth passing in front of it per second, and the computer of the DCT trajectory control device can determine the distance traveled as a function of the number of teeth indicated by the sensor and the wheel development, then estimate the current speed vv by integrating this distance traveled over time.

[0034] The on-board network RB is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume electrical energy are coupled.

[0035] The service battery BS is responsible for supplying electrical energy to the on-board network RB, in addition, here, to that supplied by the CV converter powered by the main battery BP, and sometimes instead, here, of this CV converter. For example, this service battery BS can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least by the (current) converter CV. It is considered in the following, by way of non-limiting example, that the service battery BS is of the 12 V Lithium-ion type.

[0036] The transmission chain has a GMP which is, here, purely electric and therefore which comprises, in particular, an electric motor MME, a motor shaft AM, and a transmission shaft AT. Here, the term “electric motor” means an electric machine arranged so as to provide an output torque, defined by a torque setpoint, to move the vehicle V when it is supplied with electrical energy (here) by the main battery BP (we then speak of providing a positive output torque), as well as possibly to recover torque, for example in a regenerative braking phase (we then speak of providing a negative output torque).

[0037] The operation of the GMP is supervised by a CS supervision computer.

[0038] The operation of the electric motor MME is controlled by a cal CM machine controller, and supervised by the CS supervision computer. This operational control is carried out in particular based on a voltage measurement mt which is carried out by a voltage detector on the input terminals of the MME electric motor.

[0039] It is considered in the following, by way of non-limiting example, that the electric motor MME comprises a rotor and a stator. For example, the rotor may be a permanent magnet and the stator may comprise N coils (with N > 3) placed around the rotor and supplied, in a controlled manner by the machine computer CM, with current pulses having circulation directions chosen so as to make each of them attractive or repulsive or neutral (no current) at a precise instant. It will be understood that this rotational drive of the rotor makes it possible to produce the output torque es to move the vehicle V.

[0040] For example, the rotor can be associated with a detector which is responsible for measuring its rotation speed (or rpm) periodically, for example every millisecond (or ms), and therefore for periodically providing a measurement of rotation speed vrm, for example to (at least) the machine computer CM.

[0041] It will be noted that the output torque es which is supplied by the electric motor MME on its output can, for example, be estimated as a function of at least the voltage measurement mt on the input terminals of the electric motor MME, of a current ism leaving the electric motor MME, of the rotation speed vrm of the rotor of the electric motor MME, and of the current drawn by the electric motor MME (here in the main battery BP).

[0042] Indeed, as the person skilled in the art knows, the estimation of the output torque supplied es is given by the equation es = (mt * ism * p) / vrm. p is a coefficient of efficiency of the electric motor MME which is determined using the rotation speed vrm of the rotor of the electric motor MME, the current drawn by the electric motor MME (here in the main battery BP) and the voltage measurement mt (as well as possibly the internal temperature of the stator).

[0043] The preceding equation follows from the fact that the electric power pelec received by the electric motor MME on its input terminals is equal to the product (mt * ism), and that the electric motor MME provides at output a power pmeca mechanics which is equal to the product (es * vrm) but also to the product (pelec * p), and that consequently we have the equation (es * vrm) = (mt * ism * p).

[0044] It is important to note that when the GMP comprises a thermal engine, the computer associated with the latter is arranged so as to estimate the output torque supplied by the thermal engine (equivalent of es), for example by measuring the intake inlet pressure, the intake inlet temperature and the engine speed. The computer associated with the thermal engine generally stores maps (or correspondence tables) which allow it to estimate the output torque using the three aforementioned parameters.

[0045] The electric motor MME is coupled to the motor shaft AM, to provide it with the output torque es by rotational drive. This motor shaft AM is here coupled to a reducer RD which is also coupled to the transmission shaft AT, itself coupled to a first train T1 of driving wheels, preferably via a differential DV.

[0046] It will be noted that the first train T1 is here located in the front part PVV of the vehicle V. But in a variant this first train T1 could be the one which is here referenced T2 and which is located in the rear part PRV of the vehicle V.

[0047] The CV converter is also responsible, here, during the driving phases of the vehicle V for converting part of the electric current stored in the main battery BP to supply the on-board network RB and the service battery BS (to recharge it) with converted electric current.

[0048] It will be noted, as illustrated non-limitingly in [Fig.l], that the CV converter can be part of a CH charger also comprising a recharge calculator (not illustrated) responsible, at least, for controlling the recharges of the main battery BP.

[0049] The main (or traction) battery BP may, for example, comprise electrical energy storage cells, possibly electrochemical (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type). Also for example, the main battery BP may be of the low voltage type (typically 450 V for illustration purposes). But it could be of the medium voltage or high voltage type.

[0050] It will also be noted that the main battery BP is associated with a battery box BB which notably includes a battery calculator CB. This main battery BP and its battery box BB constitute a battery pack.

[0051] It will also be noted that in the example illustrated non-limitingly in [Fig.l] the vehicle V also comprises a distribution box BD to which the service battery BS, the converter CV and the on-board network RB are coupled. This distribution box BD is responsible for distributing in the on-board network RB the electrical energy stored in the service battery BS or produced by the converter CV, for the supply of the electrical components (or equipment) coupled to the on-board network RB based on power supply requests received (in particular from the GMP CS supervision calculator).

[0052] The vehicle V also stores N road laws Irn (n = 1 to N, with N > 2) which are respectively associated with N predefined masses mpn and a function of the current speed vv of the vehicle V. For example, these N road laws Irn can be stored in the supervision computer CS or in the estimation device DE.

[0053] Each road law 1m is determined when developing a vehicle similar to vehicle V. It is used to determine the effective power peff which is supplied to the drive wheels of vehicle V for a predefined mass mpn and when vehicle V is traveling at a current speed vv.

[0054] For example, each road law 1m associated with a predefined mass mpn can be defined by the formula ((F0 + Fl*vv + F2*vv2) + (mpn*g*pp))*vv / 3600, where g is the acceleration of Earth gravity (typically equal to 9.81 ms2, pp is the percentage of the slope, and F0, Fl and F2 are coefficients associated with this predefined mass mpn and determined during the aforementioned development. It will be understood that the coefficients F0, Fl and F2 vary according to the N predefined masses mpn for which they were determined specifically and respectively.

[0055] But other 1m road laws can be used.

[0056] As mentioned above, the invention proposes in particular an estimation method intended to allow the estimation of the current mass mcv of the vehicle V.

[0057] This (estimation) method can be implemented at least partially by the estimation device DE (illustrated at least partially in FIGS. 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD. This estimation device DE can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller.

[0058] The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the estimation method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out at least one electrical or electronic operation.

[0059] In the example illustrated non-limitingly in Figures 1 and 2, the estimation device DE is part of the supervision computer CS. But this is not obligatory. Indeed, the estimation device DE could comprise its own dedicated computer, which is then coupled to the supervision computer CS, or could be part of another on-board computer (for example the supervision computer CM machine or the DCT trajectory control device calculator).

[0060] As illustrated non-limitingly in [Fig. 3], the (estimation) method, according to the invention, comprises a step 10-50 which is implemented, possibly periodically or at the request of an on-board computer, when a condition is satisfied, namely the vehicle V has a constant current speed vv.

[0061] Step 10-50 of the method comprises a sub-step 20 in which, when the aforementioned condition is satisfied, one (for example the estimation device DE) estimates an effective power pee with one of the road laws 1m for the current speed vv. It will be understood that this road law Irn is chosen from among the N.

[0062] Step 10-50 of the method also comprises a sub-step 30 in which, one (for example the estimation device DE) determines a difference dm between the estimated effective power pee and the effective power peff supplied by the GMP to the drive wheels. We then have dm = pee - peff.

[0063] For example, the effective power peff can be estimated as follows. It will be noted that this estimation can, as illustrated non-limitingly in [Fig. 3], be carried out in a sub-step 10 of step 10-50 by the estimation calculator DE or another on-board calculator (for example the machine calculator CM or the supervision calculator CS or even the calculator of the trajectory control device DCT).

[0064] First of all, we can calculate the torque at the coues wheels, which is the torque supplied to the drive wheels by the GMP, as a function of the output torque es (here supplied by the electric motor MME) and the reduction factor fred which is provided at the instant considered (here) by the reducer RD (but this could be by a gearbox). For this purpose, we can, for example, use the formula croues = cs*fred.

[0065] Then, we can estimate the effective power peff (supplied to the drive wheels) using the formula peff = (wheels*vv*ir) / (dp*1800), where dp is the diameter of the tires of the drive wheels (accessible in the vehicle V).

[0066] Step 10-50 of the method also comprises a sub-step 50 in which, when this determined difference dm is less than or equal to a threshold if chosen, one (for example the estimation device DE) chooses the predefined mass mpn which is associated with the road law Irn considered as the current mass mcv.

[0067] On the other hand, when this difference dm is greater than the threshold si, one (for example the estimation device DE) carries out at least one other estimation of effective power peff with another (1m' (with n' n)) of the road laws for the current speed vv, and another determination of difference dm until obtaining a difference dm less than or equal to the threshold si and the choice of the predefined mass mpn associated with the corresponding road law Irn' as current mass mcv.

[0068] In other words, one (for example the estimation device DE) performs again the sub-steps 20 to 50 at least once (and therefore iteratively), in order to obtain an estimated effective power pee whose difference dm with the effective power supplied peff is less than or equal to the threshold si.

[0069] We thus obtain an estimate of the current mass mcv which is fairly (or even very) precise because it results from calculations which take into account the rolling force and the aerodynamic force in a phase of the vehicle's life V in which its current speed vv is stabilized (or constant).

[0070] Thanks to this precision of the estimation of the current mass mcv, the management of the starts (or take-offs) on slope of the vehicle V is more precise and therefore the latter (V) is subject to fewer jolts. In addition, the results of the checks of the vehicle V, carried out by an authority to compare its actual consumption with its theoretical consumption and / or its actual kilometer autonomy with its theoretical kilometer autonomy, will be reliable and precise and therefore incontestable. In addition, an estimate of the current mass mcv is available whatever the percentage of slope pp of the traffic lane on which the vehicle V is traveling, and therefore including when this percentage of slope pp is zero.

[0071] It will be noted that step 10-50 of the method can also comprise, as illustrated non-limitingly in [Fig. 3], a sub-step 40 in which one (for example the estimation device DE) compares the difference dm just determined with the threshold si. If one has dm > si, then one (for example the estimation device DE) performs again the sub-steps 20 to 50 at least once (and therefore iteratively), as indicated above. On the other hand, if one has dm < si, then one (for example the estimation device DE) performs the sub-step 50 in order to choose the predefined mass mpn which is associated with the road law Irn currently in use as the current mass mcv.

[0072] It will also be noted that in step 10-50 each estimation can be carried out when the vehicle V has a current speed vv which is constant (or stabilized) for a duration which is at least equal to a predefined value.

[0073] For example, this predefined value may be between 500 ms and 2 s. As an illustrative example, this predefined value may be equal to 1 s. But other predefined values ​​may be used. For example, the predefined value may be chosen during the development phase of the vehicle V.

[0074] Also for example, when each road law Irn associated with a predefined mass mpn is defined by the formula ((F0 + Fl*vv + F2*vv2) + (mpn*g*pp))*vv / 3600, in each sub-step 20, each effective power pee estimated with a road law 1m (for example by the estimation device DE) can be equal to the value taken by the formula ((F0 + Fl*vv + F2*vv2) + (mpn*g*pp))*vv / 3600 of this road law 1m for the current speed vv.

[0075] Also for example, the threshold si can be between 20 kg and 80 kg. As an illustrative example, the threshold si can be equal to 50 kg. But other threshold values if can be used. For example, the threshold value if can be chosen during the vehicle tuning phase V.

[0076] Also for example, in step 10-50 the road laws 1m can be respectively associated with at least three predefined masses mpn which are chosen from:

[0077] - a so-called empty mass of the vehicle V,

[0078] - a so-called half-payload mass of the vehicle V (this is the empty mass of the vehicle V increased by 100 kg),

[0079] - a so-called payload mass of the vehicle V (this is the empty mass of the vehicle V with four additional people of average mass),

[0080] - a total loaded mass of the vehicle V (this is the empty mass of the vehicle V increased by the maximum authorized load), and

[0081] - a total towable mass of the vehicle V (this is the empty mass of the vehicle V increased by the maximum authorized load and the maximum authorized towing mass).

[0082] It should be noted that this list is not exhaustive. It may in fact include other predefined masses mpn which are then associated respectively with other road laws Irn.

[0083] Generally speaking, the greater the number N of road laws Irn used, the greater the precision of the estimation of the current mass mcv.

[0084] It will also be noted that during the very first iteration of the method, the very first road law Irn which is initially used can be the one which is associated with the half-payload mass of the vehicle V. But this is not an obligation.

[0085] It will also be noted, as illustrated non-limitingly in [Fig.2], that the supervision computer CS (or the calculator of the estimation device DE) can also comprise a mass memory MM1, in particular for storing the current speed vv, the gradient percentage pp, the current output torque es, the current gear reduction factor fred, the coefficients F0, Fl and F2 and associated predefined mass mpn of each road law 1m, and the tire diameter dp, as well as any intermediate data involved in all its calculations and processing.Furthermore, this supervision calculator CS (or the calculator of the estimation device DE) can also comprise an input interface IE for receiving at least the current speed vv, the gradient percentage pp, the current output torque es, the current gear reduction factor fred, the coefficients F0, Fl and F2 and associated predefined mass mpn of each road law 1m, and the tire diameter dp, to use them in calculations or processing, possibly after having shaped and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2. Furthermore, this supervision calculator CS (or the calculator of the estimation device DE) can also comprise an output interface IS, . in particular to deliver a message containing each estimate of the current mass mcv.

[0086] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the estimation method described above to estimate the current mass mcv of the vehicle V.

Claims

Claims

1. Method for estimating a current mass of a land vehicle (V), comprising a powertrain suitable for supplying effective power to drive wheels, and storing road laws respectively representative of effective powers, respectively associated with predefined masses and depending on a current speed of said vehicle (V), characterized in that it comprises a step (10-50) in which, when said vehicle (V) has a constant current speed, an effective power is estimated with one of said road laws for said current speed, then a difference between said estimated and supplied effective powers is determined, and when this difference is less than or equal to a chosen threshold, said predefined mass associated with this road law is chosen as the current mass,whereas when this difference is greater than said chosen threshold, at least one other estimate of effective power is carried out with another of said road laws for said current speed and another determination of difference until a difference less than or equal to said chosen threshold is obtained and the predefined mass associated with the corresponding road law is chosen as the current mass.,

2. Method according to claim 1, characterized in that in said step (10-50) said estimation is carried out when said vehicle (V) has a constant current speed for a duration at least equal to a predefined value.

3. Method according to claim 2, characterized in that in said step (10-50) said predefined value is between 500 ms and 2 s.

4. Method according to one of claims 1 to 3, characterized in that in said step (10-50) each road law associated with a predefined mass is defined by a formula ((F0 + Fl*vv + F2*vv2) + (mpn*g*pp))*vv / 3600, where vv is said current speed, mpn is said predefined mass, g is an acceleration of terrestrial gravity, pp is a percentage of slope of a traffic lane on which said vehicle (V) is traveling, and F0, Fl and F2 are coefficients associated with this predefined mass mpn.

5. Method according to claim 4, characterized in that in said step (10-50) each effective power estimated with a road law is equal to the value taken by the formula ((F0 + Fl*vv + F2*vv2) + (mpn*g*pp))*vv / 3600 of this road law for said current speed.

6. Method according to one of claims 1 to 5, characterized in that in said step (10-50) said threshold is between 20 kg and 80 kg.

7. Method according to one of claims 1 to 6, characterized in that in said step (10-50) said road laws are respectively associated with at least three predefined masses chosen from a so-called empty mass of said vehicle (V), a so-called half-payload mass of said vehicle (V), a so-called payload mass of said vehicle (V), a total laden mass of said vehicle (V), and a total towable mass of said vehicle (V).

8. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the estimation method according to one of claims 1 to 7, in a land vehicle (V), comprising a powertrain capable of providing drive wheels with effective power, and storing road laws respectively representative of effective powers, associated respectively with predefined masses and depending on a current speed of said vehicle (V), to estimate a current mass of said vehicle (V).

9. Estimation device (DE) for a land vehicle (V), comprising a powertrain suitable for supplying drive wheels with effective power, and storing road laws respectively representative of effective powers, respectively associated with predefined masses and depending on a current speed of said vehicle (V), characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, when said vehicle (V) has a constant current speed, in estimating an effective power with one of said road laws for said current speed, then in determining a difference between said estimated and supplied effective powers, and, when this difference is less than or equal to a chosen threshold, in choosing said predefined mass associated with this road law as the current mass, while when this difference is greater than said chosen threshold,to carry out at least one other estimate of effective power with another of said road laws for said current speed and another determination of difference until obtaining a difference less than or equal to said chosen threshold and choice of the predefined mass associated with the corresponding road law as current mass.,

10. Land vehicle (V), comprising a powertrain suitable for providing drive wheels with effective power, and storing road laws respectively representative of effective powers, respectively associated with predefined masses and depending on a current speed of said vehicle (V), characterized in that it further comprises an estimation device (DE) according to claim 9.

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