Method for validating at least one combination of transmission ratios

Abstract

The invention relates to the validation, applied to a powertrain (20) of an electric or hybrid motor vehicle (10) comprising two traction elements (41, 42, 43) and a gearbox (51, 52) adapted to ensure several combinations of transmission ratios between the traction elements and at least one output shaft (71, 72) of the gearbox, of a combination of transmission ratios, the method comprising the following steps: - acquisition of an intrinsic maximum rotational speed of each element; - calculation, for each element, on the basis of said combination of transmission ratios and the intrinsic maximum rotational speed of said element, of an upper limit of rotation relative to an output shaft driven by said element; - acquisition of an instantaneous rotational speed of a first of the elements;- calculation, based on said combination of transmission ratios and the instantaneous rotational speed, of a current rotational speed relative to the output shaft driven by said first component; - validation or not of the combination of transmission ratios based on a comparison between an upper rotational limit and said current rotational speed. Figure for the abbreviation: Fig. 1;

Description

Title of the invention: Method for validating at least one combination of transmission ratios Technical field of the invention

[0001] The present invention relates generally to the control of a powertrain of an electric or hybrid motor vehicle.

[0002] It relates more particularly to a method for validating at least one combination of transmission ratios.

[0003] It also relates to an electric or hybrid motor vehicle whose powertrain is controlled according to this method.

[0004] The invention finds a particularly advantageous application in the determination of transmission ratio change. State of the art

[0005] An electric or hybrid motor vehicle comprises a powertrain that may include at least two drive components, for example, an internal combustion engine and an electric motor, and a gearbox. It also includes an electronic unit adapted to control the vehicle's powertrain. This powertrain can typically be controlled according to several combinations of transmission ratios. A transmission ratio defines, for each component, whether that component supplies power to the drive wheels and, if so, what the multiplication (reduction or multiplication) ratio is between the input shaft attached to the rotating part of the drive component and the output shaft of the gearbox that drives the wheels. A transmission ratio thus defines a kinematic state of the powertrain.

[0006] The traction components of the powertrain, however, have one or more operating limits, notably a maximum rotational speed above which the components are in an overspeed condition, which implies mechanical risks that can lead to breakage of the traction components in use. Electric machines primarily have a maximum limit, while internal combustion engines have both a maximum and a minimum limit.

[0007] Various strategies ensure that the mechanical limits of the traction components are not exceeded. Typically, the limits of the components are expressed as a longitudinal speed of the vehicle (for example, in km / h) so that they can be compared with the instantaneous longitudinal speed of the vehicle. The latter, which represents the vehicle's current operating speed, is typically provided by the vehicle's stability control system (VDC for "Vehicle Dynamic Control").

[0008] This approach therefore requires knowledge of many technical characteristics of the vehicle, such as wheel size and tire diameter thickness, in order to convert the rotational speeds of the components into longitudinal speeds.

[0009] Thus, this approach is complex to implement and requires adjustment for each vehicle. It is also imprecise, firstly because of the difficulty in estimating certain vehicle characteristics such as tire thickness (which depends on inflation), and secondly because the current operating speed, used for comparison with the limits, is acquired by means of a vehicle system that is not dedicated to controlling the powertrain. Furthermore, the calculation can be distorted under conditions of low wheel grip (slippage) on the road surface since the wheel rotational speed is no longer proportional to the vehicle's longitudinal speed. Presentation of the invention

[0010] In this context, the present invention proposes a validation method, applied to a powertrain of an electric or hybrid motor vehicle comprising at least two drive units and at least one gearbox adapted to provide several combinations of transmission ratios between the drive units and at least one output shaft of the gearbox, of at least one combination of transmission ratios, the method comprising the following steps: - acquisition of an intrinsic maximum rotational speed of each organ; - calculation, for each component, based on said combination of transmission ratios and the intrinsic maximum rotational speed of said component, of an upper rotational limit relative to an output shaft driven by said component; - acquisition of an instantaneous rotational speed of the first of the organs; - calculation, based on said combination of transmission ratios and instantaneous rotational speed, of a current rotational speed relative to the output shaft driven by said first component; - validation or not of the combination of transmission ratios based on a comparison between one of the said upper limits of rotation and the said current rotation speed.

[0011] For the purposes of this invention, "validating" a combination means providing an indication, for example represented by a Boolean value, that allows an electronic unit responsible for controlling the gearbox, such as the vehicle's computer, to authorize the combination (the powertrain can then be controlled according to this combination) or, conversely, to reject the combination (the powertrain should not be controlled according to this combination). When the combination under consideration is the current combination, that is, the one according to which the powertrain is being controlled, rejecting the combination therefore indicates to the electronic unit that it is time to change combination.

[0012] Thus, the invention proposes to express both the limits of the traction components and the vehicle's operating speed in terms of rotational speeds. By working solely with rotational speeds, a common reference is adopted for the limits of the traction components and the vehicle's operating speed, which simplifies comparisons of limit exceedances. In other words, the rotational speeds relative to the output shafts driven by the components then represent standardized speeds that are comparable to each other.

[0013] It is therefore no longer necessary to convert the maximum rotational speeds of the traction components into longitudinal speed of the vehicle and thus to know precisely vehicle characteristics such as wheel diameter.

[0014] Furthermore, the vehicle's operating speed is determined directly by means of the instantaneous rotational speed(s) of the components. Thus, the operating speed is known very precisely. It is also directly expressed in the same system of units (for example, revolutions per minute) as the limits of the components.

[0015] Finally, the conditions of low wheel adhesion are correctly taken into account since the calculation is based on the output shaft driving the wheels whose rotational speed is, in all cases, proportional to that of the wheels.

[0016] Other advantageous and non-limiting features of the process according to the invention, taken individually or in all technically possible combinations, are as follows: - said one of the said upper limits of rotation used for comparison is the lowest upper limit of rotation among the upper limits of rotation of at least two organs; - it is planned: the acquisition of the instantaneous rotational speed of each organ, the calculation of a current rotational speed for each organ, and the current rotational speed used for comparison is the highest current rotational speed among the current rotational speeds of at least two organs; - the calculation of the upper limit of rotation is based on a ratio, which depends on said combination of transmission ratios, between: the rotation of said component, and the rotation of the output shaft driven by said component or the rotation of the wheels driven by said component; - the calculation of the current rotational speed is based on a ratio, which depends on said combination of transmission ratios, between: the rotation of said first component, and the rotation of the output shaft driven by said first component or the rotation of wheels driven by said component; - It is planned to calculate, for each component, an anticipated limit, relative to the output shaft driven by said component, which is lower than the upper rotation limit, and the comparison is made between one of the said anticipated rotation limits and the said current rotation speed; - it is planned, for each organ, to calculate the anticipated rotation limit on the basis of a temporal variation of the instantaneous rotation speed of said organ; - it is planned to acquire an intrinsic minimum rotational speed of at least one of the components and to calculate, for said component, a lower rotational limit relative to the output shaft driven by said component, and the validation or not of the combination of transmission ratios is also based on a comparison between said lower rotational limit and said current rotational speed; - said combination of transmission ratios, validated or not, is the combination that is currently used to drive the wheels of the vehicle; - it is planned: to calculate for each component an upper limit of rotation for each combination of transmission ratios, to calculate a current rotation speed for each combination of transmission ratios, to validate or not each combination of transmission ratios, each validation or not of a combination of transmission ratios being based on a comparison between one of the said upper limits of rotation and the said current rotation speed which are associated with the said combination of transmission ratios.

[0017] The invention also proposes an electric or hybrid motor vehicle comprising: - a powertrain which includes at least two traction elements and a gearbox adapted to provide several combinations of transmission ratios between the traction elements and at least one output shaft; - a computer programmed to implement a validation process for a combination of transmission ratios for the control of the powertrain according to a process such as that described above.

[0018] Of course, the various features, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Detailed description of the invention

[0019] The following description with regard to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be carried out.

[0020] On the attached drawings:

[0021] [Fig-1] is a schematic top-view representation of a vehicle according the invention.

[0022] [Fig.2] is a block diagram of a sequence of steps for implementing a method of validating a combination of transmission ratios according to the invention.

[0023] An electric or hybrid automobile 10 according to the invention is shown in [Fig. 1]. The vehicle 10 comprises a powertrain 20 for propelling the vehicle 10. In the example shown in [Fig. 1], the powertrain 20 includes, in particular, three traction elements (hereafter referred to as elements) which drive the wheels 31, 32 of the vehicle 11. The powertrain 20 here comprises: - a thermal engine 41, here connected to the front wheels 31; - an electric machine before 42, here also connected to the front wheels 31; - a rear electric machine 43, connected to the rear wheels 32.

[0024] In order to mechanically connect the components 41, 42, 43 to the wheels 31, 32, the powertrain 20 also includes a front gearbox 51 and a rear gearbox 52.

[0025] The front gearbox 51 is connected, at its input, to a primary shaft 61 of the internal combustion engine 41 and to a primary shaft 62 of the front electric motor 42. The primary shafts 61 and 62 are connected to the rotating parts of the components 61 and 62. Thus, the primary shaft 61 of the internal combustion engine 41 is connected to its crankshaft, and the primary shaft 62 of the front electric motor 42 is connected to its rotor. At its output, the front gearbox 51 is connected to a front output shaft 71 which drives, via a differential 80, two front axles 81, and by extension, the front wheels 31.

[0026] The front gearbox 51 has discrete, multiplying ratios, i.e., reduction or multiplication ratios, for the transmission between the input shaft 61 of the internal combustion engine 41 and the front output shaft 71. Here, the front gearbox 51 has four discrete ratios. The front gearbox 51 also has discrete, here two, multiplying ratios for the transmission between the input shaft 62 of the front electric machine 42 and the front output shaft 71.

[0027] Here, the front output shaft 71 drives the front wheels 31 with a fixed proportionality coefficient other than one, which means that one revolution of the front output shaft 71 does not correspond exactly to one revolution of the front wheels 31. This fixed proportionality coefficient is applied here by the differential 80. As an example, taking into account the differential 80, the ratios numbered one to four for the internal combustion engine 41 allow respectively, a reduction of 13.06, 6.27, 3.81 and 2.86; and the ratios numbered one and two for the front electric machine 42 allow respectively a reduction of 12.92 and 4.3.

[0028] Here, the front gearbox 51 is designed so that the input shaft 61 of the internal combustion engine 41 and the input shaft 62 of the front electric machine 42 can rotate at different speeds. The front gearbox 51 is, for example, designed according to E-TECH technology.

[0029] The rear gearbox 52 is connected, at its input, to the input shaft 63 of the rear electric motor 43. At its output, the rear gearbox 52 is connected to a rear output shaft 72 which drives a rear axle 82 and, by extension, the rear wheels 32. The rear gearbox 52 has discrete ratios, for example two, for the transmission between the input shaft 63 of the rear electric motor 43 and the rear output shaft 72. Here, the rear output shaft 72 drives the wheels with a fixed proportionality coefficient of one, meaning that one revolution of the rear output shaft 72 corresponds exactly to one revolution of the rear wheels 32. Alternatively, a rear differential between the rear output shaft and the rear axles can be provided, supplying a fixed proportionality coefficient other than one.

[0030] The output shafts 71, 72 are thus here output shafts of the gearboxes 51, 52. The front output shaft 71 is driven by the internal combustion engine 41 or the front electric machine 42. The rear output shaft 72 is driven by the rear electric machine 43.

[0031] The motor vehicle 10 also includes a computer 90 which is programmed here to control the powertrain 20 in the sense that it automatically determines the discrete ratios of each gearbox 51, 52. The gearboxes 51, 52 are thus here called "automatic" gearboxes, which means that the gear changes are not managed by the driver of the vehicle 10.

[0032] The control unit 90 can operate the powertrain 20 according to several combinations of transmission ratios between the components 41, 42, 43 and the output shafts 71, 72. Here, since the vehicle 10 comprises three components 41, 42, 43, each combination of transmission ratios is given by three values, each representing a discrete ratio associated with one of the components. These values ​​are positive integers or zero. For example, the transmission ratio combination "2, 2, 1" means that the second gear (of the four) is engaged for the internal combustion engine 41, the second gear (of the two) is engaged for the front electric motor 42, and the first gear (of the two) is engaged for the rear electric motor. A zero value in a combination means that the component does not provide power for traction or propulsion of the vehicle 10.Thus, for example, in the combination "1, 1, 0", the rear electric machine 43 is not in dog clutch and the other two components 41, 42 are in their respective first gear.

[0033] The control unit 90 can control the powertrain 20 according to a number of predefined gear ratio combinations. These gear ratio combinations are hereafter referred to simply as combinations. The control unit 90 only has certain combinations stored in memory since several combinations are of little interest, such as a "4, 1, 1" combination with a very high ratio for the internal combustion engine and very low ratios for the other engines. electrical. In other words, not all possible combinations are considered, but only those that make sense (the lowest ratio will almost never be used for one component and the highest for another). Therefore, a pre-selection stage for the possible combinations is included in the vehicle design process.

[0034] The computer 90 comprises at least one memory and at least one processor. Its memory stores data used in the process described below. In particular, it stores a computer application consisting of computer programs containing instructions whose execution by the processor enables the computer 90 to implement the process described below. In other words, the processor is programmed to implement the process described below.

[0035] The computer 90 also includes input interfaces adapted to receive input signals from various sensors on board the vehicle 10. Here, the input interfaces of the computer 13 allow it in particular to have access to the CAN data bus of the motor vehicle 10. In general, the computer 90 can acquire, thanks to its input interfaces, instantaneous rotation speeds of the components 41, 42, 43, that is to say the rotation speeds of the primary shafts 61, 62, 63 of the components 41, 42, 43.

[0036] The method according to the invention is illustrated in [Fig. 2]. This method makes it possible to validate at least one combination of transmission ratios, in particular the one in which the powertrain 20 is being controlled. In the example of [Fig. 2], the control unit 90 can control the powertrain 20 in twenty combinations of transmission ratios. As will be detailed below, the calculations are performed for the twenty combinations of transmission ratios in parallel.

[0037] The steps of the process are implemented here repeatedly. The computer 90 is thus programmed to implement the process recursively, that is, step by step, for example with constant time steps. A particular iteration of the process is described below.

[0038] The process begins with a first step of acquiring the intrinsic maximum rotational speed of each component 41, 42, 43. Each intrinsic maximum rotational speed depends on the design of the component 41, 42, 43 in question. This data is, for example, provided by the manufacturer of the components 41, 42, 43. It is stored in the memory of the computer 90. Acquiring this data means accessing the values ​​stored in the memory. The first step thus makes it possible to define the intrinsic limit of each component 41, 42, 43.

[0039] As shown in [Fig. 2], this step includes acquiring a maximum rotational speed V_MAX_1 of the internal combustion engine 41 (block 101), a maximum rotational speed V_MAX_2 of the front electric machine 42 (block 102), and a Maximum rotation speed V_MAX_3 of the rear electric machine 43 (block 103). The maximum rotation speed V_MAX_1 of the internal combustion engine 41 is, for example, 6000 rpm and the maximum rotation speeds V_MAX_2, V_MAX_3 of the electric machines 42, 43 are 10,000 rpm.

[0040] Here, the first step also includes acquiring an intrinsic minimum rotational speed V_MIN_1 of the internal combustion engine 41 (also in block 101). This minimum rotational speed V_MIN_1 prevents the internal combustion engine 41 from stalling. Electrical machines do not have an intrinsic minimum rotational speed. In other words, the intrinsic minimum rotational speeds of electrical machines are equal to zero.

[0041] The process continues with a second calculation step, for each component 41, 42, 43, of an upper limit of rotation of the output shaft 71, 72 driven by said component 41, 42, 43. The second step here more specifically includes the calculation of an upper limit of rotation for each component and for each combination.

[0042] In this second step, we determine which speeds at the output shafts 71, 72 of the gearboxes 51, 52 are supported by the components 41, 42, 43.

[0043] To this end, the control unit 90 stores in memory, for each component 41, 42, 43 and for each combination, a ratio between the rotational speed of said component 41, 42, 43 and the rotational speed of the output shaft 71, 72 driven by said component 41, 42, 43. Each ratio represents, for a given component and a given combination, the multiplication provided by the gearbox connected to the component, for the discrete ratio indicated by the combination. Each ratio is therefore defined here as the number of revolutions of the input shaft corresponding to one revolution of the output shaft.

[0044] Alternatively, the ratios can take into account the fixed proportionality coefficients defined previously between the output shafts (front and rear) and the wheels. This then amounts to also taking into account the differential between the front axles (and the rear differential when present). Thus, for each component, the ratios can also be defined as the number of revolutions of the input shaft corresponding to one revolution of the wheels driven by said component. As an example, defined in this way, the ratio of the internal combustion engine for the combination "1, 1, 0" would be 13.06 (which corresponds to the gear ratio described previously).

[0045] Here, the calculator 90 therefore has in memory twenty ratios, referenced R_1 on the [Fig.2], for the thermal engine 41 (which can take four values ​​representing the four discrete ratios), twenty ratios, referenced R_2 and R_3, for each electric machine 42, 43 (which can take two values ​​representing the two discrete ratios).

[0046] As shown in [Fig. 2], this second step involves calculating an upper rotation limit L_SUP_1 for the internal combustion engine 41 (block 111). This upper rotation limit L_SUP_1 is here a vector of twenty values, each value being associated bijectively with one of the twenty combinations. Each value of this upper rotation limit L_SUP_1 is calculated by dividing the maximum rotation speed V_MAX_1 of the heat engine 41 by the ratio of the associated combination.

[0047] Similarly, the second step includes calculating an upper rotation limit L_SUP_2 for the front electric machine 42 (block 112) and an upper rotation limit L_SUP_3 for the rear electric machine 43 (block 113). These upper rotation limits L_SUP_2 and L_SUP_3 are also respectively vectors of twenty values, each value of a vector being bijectively associated with one of the twenty combinations, each value of a vector being calculated by dividing the maximum rotation speed V_MAX_2, V_MAX_3 by the ratio of the associated combination.

[0048] Here, the second step also includes calculating a lower rotation limit L_INF_1 for the internal combustion engine 41 (also in block 111). This lower rotation limit L_INF_1 is also a vector of twenty values, each value being bijectively associated with one of the twenty combinations. Each value of this lower rotation limit L_INF_1 is calculated by dividing the minimum rotational speed V_MIN_1 of the internal combustion engine 41 by the ratio of the associated combination.

[0049] The method then includes a third step of acquiring an instantaneous rotational speed of each of the organs 41, 42, 43.

[0050] Here, the computer 90 acquires, via the CAN data bus, the instantaneous rotational speed V_INS_1 of the primary shaft 61 of the internal combustion engine 41 (block 121), the instantaneous rotational speed V_INS_2 of the primary shaft 62 of the front electric machine 42 (block 122) and the instantaneous rotational speed V_INS_3 of the primary shaft 63 of the rear electric machine 43 (block 123).

[0051] The instantaneous rotational speeds V_INS_1, V_INS_2, V_INS_3 allow, in a fourth step of the process, the calculation of a current rotational speed of the output shaft 71, 72 driven by each of the components 41, 42, 43. The fourth step here more specifically includes the calculation of a current rotational speed for each component and for each combination.

[0052] The fourth step thus aims to determine the rotational speeds of the output shafts 71, 72 of each gearbox 51, 52 taking into account the rotational speed of each component 41, 42, 43.

[0053] As shown in [Fig. 2], this fourth step involves calculating a current rotational speed V_COU_1 for the heat engine 41 (block 131). This current rotational speed V_COU_1 is a vector of twenty values, each value being bijectively associated with one of the twenty combinations. Each value of this current rotational speed V_COU_1 is calculated by dividing the instantaneous rotational speed V_INS_1 of the heat engine 41 by the ratio of the associated combination.

[0054] Similarly, the fourth step includes calculating a current rotational speed V_COU_2 for the forward electric machine 42 (block 132) and a current rotational speed V_COU_3 for the rear electric machine 43 (block 133). These current rotational speeds V_COU_2, V_COU_3 are also respectively vectors of twenty values, each value of a vector being bijectively associated with one of the twenty combinations, each value of a vector being calculated by dividing the instantaneous rotational speed V_INS_2, V_INS_3 by the ratio of the associated combination.

[0055] The instantaneous rotation speeds V_INS_1, V_INS_2, V_INS_3 allow, in a fifth step, for the calculation, for each component 41, 42, 43, of an anticipated limit of the output shaft 71, 72 driven by said component 41, 42, 43. The fourth step here more specifically includes the calculation of an anticipated limit for each component and for each combination.

[0056] Advantageously, the anticipated limits are more restrictive than the upper and lower limits. They thus provide a safety margin by taking into account the temporal evolution of the current regime, that is to say, the instantaneous rotational speeds. In other words, the anticipated limits allow for consideration of an acceleration or deceleration of the vehicle 10 so as not to permit a combination that would very quickly be rejected due to the change in speed of the vehicle 10.

[0057] For this, the calculator 90 first estimates the time variation of the instantaneous rotational speed V_INS_1, V_INS_2, V_INS_3 of each component 41, 42, 43.

[0058] As shown in [Fig. 2], the computer 90 calculates a time derivative D_1 of the instantaneous rotational speed V_INS_1 of the internal combustion engine 41 (block 141). This derivative D_1 is calculated discretely, for example, over the last three or four time steps, i.e., based on the last three or four instantaneous rotational speeds V_INS_1 of the internal combustion engine 41 that have been acquired. Thus, the derivative D_1 is calculated, for example, as the difference between the most recently acquired instantaneous rotational speed V_INS_1 and the instantaneous rotational speed V_INS_1 acquired three time steps earlier, divided by the duration of the three time steps.

[0059] Similarly, the calculator 90 calculates a time derivative D_2 of the instantaneous rotational speed V_INS_2 of the forward electric machine 42 (block 142) and a time derivative D_2 of the instantaneous rotational speed V_INS_3 of the rear electric machine 43 (block 143).

[0060] During the first iteration of the process, the derivatives are considered to be equal to zero. During the second iteration, the derivatives are calculated, for example, over two time steps, and so on until the instantaneous velocities over three or four No time is available.

[0061] During this fifth step, the calculator 90 determines, for each component and for each combination, a reduction.

[0062] For this purpose, the control unit 90 stores a reduction coefficient in memory for each component 41, 42, 43 and for each combination. The reduction coefficients are determined empirically, for example, during test sessions with the vehicle 10 equipped with the control unit 90.

[0063] Here, the calculator 90 therefore has in memory twenty reduction coefficients, referenced CR_1 on the [Fig.2], for the thermal engine 41 (which can take four values ​​for the four discrete ratios), twenty reduction coefficients, referenced CR_2 and CR_3, for each electric machine 42, 43 (which can take two values ​​for the two discrete ratios).

[0064] As shown in [Fig. 2], the computer 90 calculates a reduction RED_1 of the internal combustion engine 41 (block 151). This reduction RED_1 is here a vector of twenty values, each value being bijectively associated with one of the twenty combinations. Each value of this reduction RED_1 is calculated by multiplying the derivative D_1 of the internal combustion engine 41 by the reduction coefficient of the associated combination.

[0065] Similarly, the computer 90 calculates a reduction RED_2 for the front electric machine 42 (block 152) and a reduction RED_3 for the rear electric machine 43 (block 153). These reductions RED_2, RED_3 are also respectively vectors of twenty values, each value of a vector being bijectively associated with one of the twenty combinations, each value of a vector being calculated by multiplying the derivative D_2, D_3 by the reduction coefficient of the associated combination.

[0066] Here, the fifth step also includes calculating an increase A_1 for the internal combustion engine 41 (also in block 151). For this purpose, the control unit 90 has in memory, for the internal combustion engine 41, for each combination, an increase coefficient. The increase coefficients are, for example, determined empirically during test sessions with the vehicle 10 equipped with the control unit 90. The increase coefficients are, for example, between 10 and 500. The control unit 90 therefore has in memory twenty increase coefficients, referenced CA_1 in [Fig. 2] (which can take four values ​​for the four discrete ratios). The increase A_1 is also a vector of twenty values, each value being associated with one of the twenty combinations. Each value of this increase A_1 is calculated by multiplying the derivative D_1 of the heat engine 41 by the increase coefficient of the associated combination.

[0067] The fifth step finally includes the calculation of the anticipated limits of each organ 41, 42, 43.

[0068] As shown in [Fig.2], calculator 90 calculates an anticipated upper limit L_ANT_SUP_1 of the internal combustion engine 41 is calculated by taking the difference, in vector form, between the upper rotation limit L_SUP_1 and the reduction RED_1 of the internal combustion engine 41 (block 161). Each value of the anticipated upper limit L_ANT_SUP_1 is thus bijectively associated with one of the combinations and is defined as the difference between the value of the upper rotation limit L_SUP_1 and the value of the reduction RED_1 associated with said combination.

[0069] Similarly, the control unit 90 calculates an anticipated upper limit L_ANT_SUP_2 of the front electric machine 42 by taking the difference, in a vectorial manner, between the upper rotation limit L_SUP_2 and the reduction RED_2 of the front electric machine 42 (block 162). The control unit 90 also calculates an anticipated upper limit L_ANT_SUP_3 of the rear electric machine 43 by taking the difference, in a vectorial manner, between the upper rotation limit L_SUP_3 and the reduction RED_3 of the rear electric machine 43 (block 163).

[0070] Here, the calculator 90 also calculates an anticipated lower limit L_ANT_INF_1 of the heat engine 41 by summing, in a vectorial manner, between the lower rotation limit L_INF_1 and the increase A_1 of the heat engine 41 (also at block 161).

[0071] The method then includes a sixth selection step among the upper anticipated limits and the current rotation speeds. The idea of ​​this sixth step is to associate each combination with one of the upper anticipated limits and one of the current rotation speeds in order to take into account the most critical case. In other words, for each combination, this amounts to determining which upper anticipated limit is most likely to be exceeded in order to subsequently reduce the validation to a single comparison (with regard to the upper anticipated limits).

[0072] During the sixth step, the computer 90 specifically selects the lowest upper anticipated limit L ANT SUP 1, L ANT SUP 2, L ANT SUP 3 among those of all components 41, 42, 43 (block 200). It stores the selected upper anticipated limit, here referenced L_ANT_SUP in [Fig. 2], for subsequent steps.

[0073] Here, this selection is made taking into account the operating mode of the vehicle 10, referenced as M in [Fig. 2]. For example, when the vehicle 10 operates in a purely electric mode, the selection is made only from among the upper anticipated limits L_ANT_SUP_2, L_ANT_SUP_3 of the electric machines 42, 43. When the vehicle 10 operates in a hybrid mode, the selection is made from among all the upper anticipated limits L_ANT_SUP_1, L_ANT_SUP_2, L_ANT_SUP_3. Generally, if a component 41, 42, 43 does not participate in the traction of the vehicle 10 (in practice when it is not engaged), when calculator 90 implements the sixth step, its anticipated upper limit is not taken into account for the selection.

[0074] Symmetrically, the computer 90 specifically selects the highest current rotational speed V_COU_1, V_COU_2, V_COU_3 from among those of all the components 41, 42, 43 (also in block 200). It records the selected current rotational speed, here referenced V_COU in [Fig.2], for subsequent steps.

[0075] Here again, this selection is made taking into account the operating mode M of the vehicle 10. If a component 41, 42, 43 does not participate in the traction of the vehicle 10 when the computer 90 implements the sixth step, its current rotational speed is not taken into account for the selection

[0076] In the sixth step, the control unit 90 also stores the lower anticipated limit L_ANT_INF_1 of the internal combustion engine 41 in memory for subsequent steps; this is therefore the selected lower anticipated limit. However, it does not store it in memory if the operating mode M of the vehicle 10 indicates that the internal combustion engine 41 is not involved in traction (100% electric mode). In this case, the subsequent steps that depend on it (blocks 303 and 304) are not implemented. This is equivalent to considering the selected lower anticipated limit that the control unit stores in memory as equal to zero.

[0077] The method then includes a seventh step of comparing the current regime, represented by the current rotation speed selected in the sixth step, with the limits of the components, represented by the anticipated upper limit and the anticipated lower limit selected in the sixth step.

[0078] The seventh step thus corresponds to the testing of the limits of the components in relation to a current state of the vehicle, which subsequently allows decisions to be made on the combinations (in the seventh step).

[0079] As shown in [Fig. 2], with regard to the upper limit, the computer 90 calculates the difference between the selected upper anticipated limit L_ANT_SUP and the selected current rotational speed V_COU (block 301). This difference is calculated vectorially. The result of this difference, called the upper difference and referenced DIF_SUP in [Fig. 2], is therefore a vector, here with twenty values ​​for the twenty combinations, each value being bijectively associated with one of the combinations and being defined as the difference between the value of the selected upper anticipated limit L_ANT_SUP and the value of the current rotational speed V_COU associated with said combination.

[0080] Calculator 90 then compares the upper difference DIF_SUP to a vector of upper threshold values ​​OFF_SUP (block 302). The vector of upper threshold values ​​includes a value for each of the combinations. The upper threshold values ​​OFF_SUP thus represent an additional safety measure enabling ensure that the limits of the components are not exceeded. The upper threshold values ​​OFF_SUP are strictly greater than zero; they are, for example, determined empirically during test sessions with vehicle 10 equipped with computer 90.

[0081] The result of this comparison is a vector of Booleans (here twenty Booleans for the twenty combinations) referenced B_SUP in [Fig. 2]. Each Boolean is thus bijectively associated with one of the combinations; its value is one when, for said combination, the value of the upper difference DIF_SUP is greater than or equal to the upper threshold value, and conversely, its value is zero when, for said combination, the value of the upper difference DIF_SUP is strictly less than the upper threshold value.

[0082] With regard to the lower limit, the calculator 90 calculates the difference between the selected current rotational speed V_COU and the selected lower anticipated limit L_ANT_INF (block 303). This difference is calculated vectorially. The result of this difference, called the lower difference and referenced DIF_INF in [Fig. 2], is therefore a vector, here of twenty values ​​for the twenty combinations, each value being bijectively associated with one of the combinations and being defined as the difference between the value of the selected current rotational speed V_COU and the value of the selected lower anticipated limit L_ANT_INF that are associated with said combination.

[0083] The control unit 90 then compares the lower difference DIF_INF to a vector of lower threshold values ​​OFF_INF (block 304). The vector of lower threshold values ​​includes a value for each combination. The lower threshold values ​​OFF_INF thus represent an additional safeguard to ensure that the lower limit of the internal combustion engine is not exceeded. The lower threshold values ​​OFF_INF are strictly greater than zero; they are, for example, determined empirically during test sessions with the vehicle 10 equipped with the control unit 90.

[0084] The result of this comparison is a vector of booleans (here twenty booleans for the twenty combinations) referenced B_INF in [Fig. 2]. Each boolean is thus associated with one of the combinations; its value is one when, for said combination, the value of the lower difference DIF_INF is greater than or equal to the lower threshold value, and conversely, its value is zero when, for said combination, the value of the lower difference DIF_INF is strictly less than the lower threshold value.

[0085] The process finally includes a seventh step of validating or not the combinations on the basis of the comparisons made in the sixth step.

[0086] Here, the calculator 90 performs a logical operation of the type "and" ("and" in (English) between the Boolean vectors B_SUP, B_INF resulting from the sixth step (block 400). Calculator 90 thus constructs a validation vector, referenced V in [Fig. 2]. The validation vector V here comprises twenty Booleans for the twenty combinations. Each Boolean in the validation vector V is bijectively associated with one of the combinations and is equal to one when the two Booleans (one for each validation vector B_SUP, B_INF) resulting from the sixth step and associated with said combination are both equal to one. Each Boolean in the validation vector V is equal to zero in the other cases, that is, when at least one of the Booleans resulting from the sixth step and associated with said combination is equal to zero.

[0087] This validation vector V thus indicates the valid combinations, that is, those for which the Boolean value is equal to one. These valid combinations therefore respect the limits defined for the organs. Conversely, it also indicates the invalid combinations, that is, those for which the Boolean value is equal to zero and which therefore do not respect the limits defined for the organs.

[0088] This validation vector V therefore allows the computer 90 responsible for controlling the powertrain to decide which combinations it can allow and which combinations it can reject.

[0089] This method allows the control unit 90 to determine whether the current gear ratio combination used to drive the wheels 31, 32 of the vehicle 10 should be permitted or rejected. In this case, the control unit 90 analyzes, in particular, the Boolean value of the validation vector V associated with the current combination when the method is implemented (specifically, the seventh step). If this Boolean value is zero, this instructs the control unit 90 to change the combination.

[0090] Thus, an overall method for selecting a combination is provided. This overall method comprises, firstly, the method according to the invention applied at least to the current combination. This overall method then comprises a step of changing the combination (i.e., changing the ratios) if the current combination is not validated. This overall method can also be applied to all the combinations considered (or a subset thereof). When the current combination is not validated, the new combination can be selected from among those that have been validated.

[0091] The present invention is in no way limited to the embodiments described and represented, but a person skilled in the art will be able to make any variation in accordance with the invention.

[0092] For example, in terms of traction components, the powertrain may comprise only the two electric machines (and not the internal combustion engine). The process then relates solely to determining and comparing with upper limits. The powertrain may also comprise only the front electric machine and the internal combustion engine. In this case, the powertrain includes only the front gearbox and front output shaft (and not the rear gearbox and output shaft).

[0093] The upper and lower threshold values ​​can be equal to zero. The Boolean vectors can then be determined directly from a comparison between the selected anticipated limits and the selected current rotation speed.

[0094] The anticipated limits may not be implemented. This amounts to considering that the reductions and the increase are equal to zero, which is indeed the case when the derivatives are zero. The upper anticipated limits are then equal to the upper limits and the lower anticipated limit is then equal to the lower limit.

[0095] In the third step, it is possible to acquire only the instantaneous rotational speed of one of the components. According to this variant, it is possible to acquire the instantaneous rotational speed of any of the components. A single current rotational speed is then calculated, in the fourth step, based on the instantaneous rotational speed of this single component. This single current rotational speed is then automatically selected as the current rotational speed selected in the sixth step.

[0096] The method may not be implemented for all combinations in parallel but for only one or some of the predefined combinations, in particular only for the current combination. If it is implemented for a single combination, the variables that are vectors in the example in [Fig. 2] may then comprise a single value relating solely to that combination.

[0097] As described above, the ratios can be defined not with respect to the number of revolutions of the output shafts but with respect to the number of revolutions of the wheels connected to these output shafts. In this case, the upper limits of rotation remain, however, quite "relative" to the output shafts driven by the components, since there is a fixed coefficient between the number of revolutions of the wheels and the number of revolutions of the output shafts (the number of revolutions of the wheels being linearly dependent on the number of revolutions of the output shafts). Of course, to implement the process, the ratios of all the components (the internal combustion engine and two electric machines) are defined in the same way, that is, either directly with respect to the output shafts or with respect to the wheels.

[0098] The number of discrete organ ratios may vary from the examples given previously, as may the number of combinations, which may be greater or less than twenty.

[0099] The control of the powertrain can be carried out not by the computer but by a dedicated electronic unit.

[0100] The instantaneous change in rotational speed can be determined based on various vehicle sensors. For example, the speed change can be determined based on the states of the accelerator or brake pedals, which allow for anticipating changes in vehicle speed. The speed change can also be determined based on measurements of the vehicle's longitudinal speed.

Claims

Claims

1. Validation method, applied to a powertrain (20) of an electric or hybrid motor vehicle (10) comprising at least two traction members (41, 42, 43) and at least one gearbox (51, 52) adapted to ensure several combinations of transmission ratios between the traction members (41, 42, 43) and at least one output shaft (71, 72) of the gearbox (51, 52), of at least one combination of transmission ratios, the method comprising the following steps: - acquisition of a maximum rotation speed (V_MAX_1, V_MAX_2, V_MAX_3) intrinsic to each member (41, 42, 43); - calculation, for each member (41, 42, 43), on the basis of said combination of transmission ratios and the maximum rotation speed (V_MAX_1, V_MAX_2, V_MAX_3) intrinsic to said member (41, 42, 43), of an upper rotation limit (L_SUP_1, L_SUP_2, L_SUP_3) relating to an output shaft (71, 72) driven by said member (41, 42, 43);- acquisition of an instantaneous rotation speed (V_INS_1, V_INS_2, V_INS_3) of a first of the members (41, 42, 43); - calculation, on the basis of said combination of transmission ratios and the instantaneous rotation speed (V_INS_1, V_INS_2, V_INS_3), of a current rotation speed (V_COU_1, V_COU_2, V_COU_3) relating to the output shaft (71, 72) driven by said first member (41, 42, 43); - validation or not of the combination of transmission ratios on the basis of a comparison between one of said upper rotation limits (L_SUP_1, L_SUP_2, L_SUP_3) and said current rotation speed (V_COU_1, V_COU_2, V_COU_3).;

2. The method of claim 1, wherein said one of said upper rotation limits (L_SUP_1, L_SUP_2, L_SUP_3) used for comparison is the lowest upper rotation limit (L_SUP_1, L_SUP_2, L_SUP_3) among the upper rotation limits (L_SUP_1, L_SUP_2, L_SUP_3) of the at least two members (41, 42, 43).

3. Method according to claim 1 or 2, in which it is provided: - the acquisition of the instantaneous rotation speed (V_INS_1, V_INS_2, V_INS_3) of each member (41, 42, 43); - calculating a current rotation speed (V_COU_1, V_C0U_2, V_C0U_3) for each member (41, 42, 43); and in which, the current rotation speed (V_COU_1, V_C0U_2, V_C0U_3) used for the comparison is the highest current rotation speed (V_COU_1, V_C0U_2, V_C0U_3) among the current rotation speeds (V_COU_1, V_C0U_2, V_C0U_3) of the at least two members (41, 42, 43).

4. Method according to one of claims 1 to 3, wherein the calculation of the upper rotation limit (L_SUP_1, L_SUP_2, L_SUP_3) is based on a ratio (R_l, R_2, R_3), which depends on said combination of transmission ratios, between: - the rotation of said member (41, 42, 43); and - the rotation of the output shaft (71, 72) driven by said member (41, 42, 43) or the rotation of the wheels (31, 32) driven by said member (41, 42, 43).

5. Method according to one of claims 1 to 4, in which the calculation of the current rotation speed (V_COU_1, V_C0U_2, V_C0U_3) is based on a ratio, which depends on said combination of transmission ratios, between: - the rotation of said first member (41, 42, 43); and - the rotation of the output shaft (71, 72) driven by said first member (41, 42, 43) or the rotation of the wheels (31, 32) driven by said member (41, 42, 43).

6. Method according to one of claims 1 to 5, in which it is provided to calculate, for each member (41, 42, 43), an anticipated limit (L_ANT_SUP_1, L_ANT_SUP_2, L_ANT_SUP_3), relating to the output shaft (71, 72) driven by said member (41, 42, 43), which is lower than the upper rotation limit (L_SUP_1, L_SUP_2, L_SUP_3), and in which the comparison is carried out between one of said anticipated rotation limits (L_ANT_SUP_1, L_ANT_SUP_2, L_ANT_SUP_3) and said current rotation speed (V_COU_1, V_C0U_2, V_C0U_3).

7. Method according to claim 6, in which it is provided, for each member (41, 42, 43), to calculate the anticipated rotation limit (L_ANT_SUP_1, L_ANT_SUP_2, L_ANT_SUP_3) on the basis of a temporal variation (D_l, D_2, D_3) of the instantaneous rotation speed (L_ANT_SUP_1, L_ANT_SUP_2, L_ANT_SUP_3) of said member (41, 42, 43).

8. Method according to one of claims 1 to 7, in which it is provided to acquire a minimum rotation speed (V_MIN_1) intrinsic to at least one of the members (41, 42, 43) and to calculate, for said member (41, 42, 43), a lower rotation limit (L_INF_1) relative to the output shaft (71, 72) driven by said member (41, 42, 43), and in which the validation or not of the combination of transmission ratios is also based on a comparison between said lower rotation limit (L_INF_1) and said current rotation speed (V_COU_1).

9. Method according to one of claims 1 to 8, in which said combination of transmission ratios validated or not is the combination which is currently used to drive the wheels (31, 32) of the vehicle (10).

10. Method according to one of claims 1 to 9, in which it is provided: - for each member (41, 42, 43), to calculate an upper rotation limit (L_SUP_1, L_SUP_2, L_SUP_3) for each combination of transmission ratios; - to calculate a current rotation speed (V_COU_1, V_COU_2, V_COU_3) for each combination of transmission ratios; - to validate or not each combination of transmission ratios, each validation or not of a combination of transmission ratios being based on a comparison between one of said upper rotation limits (L_SUP_1, L_SUP_2, L_SUP_3) and said current rotation speed (V_COU_1, V_COU_2, V_COU_3) which are associated with said combination of transmission ratios.

11. Electric or hybrid motor vehicle (10) comprising: - a powertrain (20) which comprises at least two traction members (41, 42, 43) and a gearbox (51, 52) adapted to provide several combinations of transmission ratios between the traction members (41, 42, 43) and at least one output shaft (71, 72); - a computer (90) programmed to implement a method for validating a combination of transmission ratios for controlling the powertrain (20) according to one of claims 1 to 10.

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