Method for determining an operating range of a hybrid motor vehicle battery

Abstract

The invention relates to a method for controlling a powertrain of a hybrid motor vehicle, the powertrain comprising an internal combustion engine and an electric machine supplied with current by a storage battery, the method comprising the steps of: - acquiring a first item of data relating to a temperature (Text) in or around the motor vehicle; - acquiring a second item of data relating to the ageing of the battery; - determining an operating range (Pu) of the battery according to the first item of data and of the second item of data; and - controlling the powertrain according to the determined operating range. According to the invention, the operating range comprises at least two separate storage battery charge level zones (BSOC), including a preferred zone (III) and a lower zone (I), and, when the charge level of the battery is located in the lower zone, the powertrain is controlled such that at least one convenience function of the powertrain is deactivated and at least one primary function of the powertrain remains activated.

Description

TITLE OF THE INVENTION: METHOD FOR DETERMINING A RANGE OF USE OF A HYBRID MOTOR VEHICLE BATTERY TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of hybrid vehicles, that is to say vehicles comprising a powertrain equipped with an electric machine supplied with electric current by a so-called traction battery, and an internal combustion engine supplied with fuel.

[0002] The invention relates more particularly to a method for controlling such a powertrain, making it possible to maintain the charge level of the traction battery within an adequate usage range.

[0003] The invention finds a particularly advantageous application in hybrid vehicles with limited electric autonomy, that is to say in vehicles equipped with traction batteries having reduced capacities, typically less than 10kWh. STATE OF THE ART

[0004] A hybrid vehicle has a conventional thermal powertrain (with an internal combustion engine and a fuel tank) and an electric powertrain (with an electric machine and a storage battery).

[0005] Such a hybrid vehicle can be towed by its thermal drivetrain alone, or simultaneously by its two electric and thermal drivetrains.

[0006] The storage battery has a limited operating range compared to the entire range that could theoretically be used. For example, it is not desirable to completely discharge the traction battery, unless it damages it.

[0007] Determining this range of use results from a compromise between different parameters such as the total energy that we want to make available (we want to maximize the upper limit and minimize the lower limit of this range), the expected lifespan of the battery (we must then minimize the upper limit to optimize this lifespan), the minimum electrical power that we want the battery to be able to develop at any time (we must then increase the lower limit so that this available electrical power remains above a threshold)...

[0008] This compromise must also guarantee satisfactory performance both in terms of pollution control and fuel consumption savings, throughout the vehicle's lifespan.

[0009] In the event that the battery is used to start the internal combustion engine, this compromise must also take into account the fact that this start must be possible in all situations, even after prolonged parking of the vehicle at low temperatures.

[0010] It is in this context that document FR3025663 proposes a method according to which the minimum charge level of the battery is determined so as to increase as the battery ages. PRESENTATION OF THE INVENTION

[0011] The present invention proposes to achieve the above-mentioned compromise in a different way.

[0012] More particularly, the invention proposes a method for controlling a hybrid motor vehicle powertrain, comprising steps of: - acquisition of initial data relating to a temperature in or around the motor vehicle, - acquisition of a second piece of data relating to the aging of the accumulator battery, - determining a range of use of the storage battery, based on the first data and the second data, this range of use comprising at least two distinct charge level zones of the storage battery, including a preferred zone and a lower zone, and - control of the powertrain differently depending on the determined range of use, such that, when the charge level of the storage battery is located in the lower zone, the powertrain is controlled by deactivating at least one convenience function of the powertrain and leaving at least one primary function of the powertrain active.

[0013] On the contrary, all primary and convenience functions are left active when the charge level of the storage battery is within the preferred zone.

[0014] Thus, thanks to the invention, the lower zone forms a buffer zone between the zone of current use of the battery and the zone in which the battery is not usable. This buffer zone differs from the preferred zone in that when the charge level of the traction battery is there, the powertrain is controlled in a particular way. In this way, when the charge level of the traction battery drops, it is not intended to abruptly interrupt the use of this battery but rather to gradually deactivate certain of its uses. This solution proves more comfortable for the user and offers better performance in terms of fuel savings and pollution control.

[0015] This solution even allows the minimum battery charge threshold to be lowered since only essential uses will be authorized to draw current from the battery when its charge level is within the buffer zone.

[0016] Other advantageous and non-limiting characteristics of the method according to the invention, taken individually or in all technically possible combinations, are the following: - the electric machine being adapted to start the internal combustion engine, the primary function is to authorize the starting of the internal combustion engine; - the approval function consists of authorizing the electric machine to propel the motor vehicle; - the second data includes the age of the accumulator battery; - said determination step is carried out using at least two distinct maps in each of which a predefined range of use varies as a function of the first data item only, the two maps corresponding to distinct second data items; - the range of use is determined by reading in at least two maps of the limits of the predefined range of use associated with the first acquired data, then by calculating limits of the range of use according to the limits read and the second data; - the preferred zone has a lower charge level limit which passes through a defined point such that when the temperature outside the motor vehicle is -10°C and the storage battery delivers a predetermined power for a predetermined duration, the charge level does not reach the lower zone; - the preferred zone has an upper limit of charge level which passes through a defined point such that when the temperature outside the motor vehicle is 10°C and the storage battery receives a predetermined power for a predetermined duration, the charge level initially on the upper limit does not go outside the operating range; - said range of use comprises an upper zone and, when the charge level of the accumulator battery is located in this upper zone, the powertrain is controlled so that the electric machine propels the motor vehicle; - said operating range comprises an intermediate zone located between the preferred zone and the zone and, when the charge level of the storage battery is located in this intermediate zone, the powertrain is controlled so that the internal combustion engine recharges the storage battery when it is in a range of high-efficiency operating points.

[0017] The invention also relates to a hybrid motor vehicle, comprising: - a powertrain which comprises an internal combustion engine and an electric machine supplied with current by a storage battery, and - a computer programmed to implement a control method as mentioned above.

[0018] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. DETAILED DESCRIPTION OF THE INVENTION

[0019] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0020] On the attached drawings:

[0021] [Fig. 1] is a schematic top view of a vehicle according to the invention, equipped with an accumulator battery;

[0022] [Fig. 2] is a graph illustrating a range of use of the storage battery at the beginning of its life; and

[0023] [Fig. 3] is a graph illustrating a range of use of the accumulator battery at the end of its life.

[0024] In Figure 1, a motor vehicle 1 is shown.

[0025] This motor vehicle could be of any type (truck, bus, ship, airplane, etc.). This is a car which typically has wheels 11, 12 and a chassis which supports in particular a powertrain 15, bodywork elements and passenger compartment elements.

[0026] This motor vehicle 1 is of the hybrid type. Therefore, the powertrain 15 comprises a thermal drive train and an electric drive train.

[0027] The thermal powertrain comprises in particular a fuel tank 17A, a fuel supply circuit which originates in the tank, and an internal combustion engine 17 supplied with fuel by the supply circuit.

[0028] The electric traction chain comprises a 16A accumulator battery (called a “traction battery”) and at least one electric machine 16 supplied with electric current by the traction battery.

[0029] Different powertrain configurations could be considered.

[0030] Here, this configuration is such that the hybrid vehicle can be towed by its thermal drivetrain alone (in all-thermal mode) or simultaneously by its two electric and thermal drivetrains.

[0031] This configuration is such that it is possible to regenerate the 16A traction battery, that is to say to recharge it, in two different ways.

[0032] The first consists of performing regenerative braking, that is to say braking during which the kinetic energy of the vehicle is transformed into electrical energy to recharge the battery.

[0033] The second consists of using the internal combustion engine 17. This second way of regenerating the traction battery is preferably used in operating ranges of the internal combustion engine in which the efficiency of the latter is high.

[0034] Here, the electric machine 16 is coupled to the internal combustion engine 17 by a box 18 such that it can serve as an alternator for this engine.

[0035] In the embodiment envisaged here, it is therefore an alternator-starter which has the function of: - carry out the regeneration of the traction battery, - start the internal combustion engine (no dedicated starter is provided), and - tow the motor vehicle 10 if necessary (in conjunction with the internal combustion engine).

[0036] The traction battery can be of any type, for example of the Lithium-Ion type. It comprises a housing which houses electrochemical cells. It has a limited voltage at its terminals, preferably less than 100 V (here of the order of 50 V). It also has a reduced capacity, typically less than 10 kWh. Due to these characteristics, it will not be able to tow the motor vehicle 10 on its own, but will however be able to assist the internal combustion engine.

[0037] This traction battery has a BSOC charge level, which will be defined here as the ratio between the instantaneous capacity of the battery and its nominal capacity. This charge level is expressed as a percentage.

[0038] It presents a state of aging that could be expressed in different ways. Here, it will be expressed in number of years of use of the battery. Alternatively or in addition, it could be expressed using a parameter referenced SOHE (State Of Health Energy), relating to the ratio of the maximum energy (i.e. capacity) that the traction battery can store at a current time to the maximum energy that the battery could store at the beginning of its life.

[0039] This traction battery also includes a BMS (Battery Management System) control unit which allows the characteristics of the cells and the battery to be measured (terminal voltage, BSOC charge level, etc.).

[0040] The motor vehicle also includes an electronic control unit, called a calculator here, which in particular allows the two aforementioned drive chains to be controlled (in particular the power developed by the electric machine and by the internal combustion engine).

[0041] The calculator includes a processor, a storage unit (hereinafter called memory), and a communication interface.

[0042] Thanks to its interface, the calculator is adapted to communicate with the BMS control unit and with sensors, in particular to determine the external temperature Text (defined as the instantaneous temperature on the external face of the battery but it could be another temperature, for example outside the motor vehicle). It is also adapted to control the internal combustion engine 17 and the electric machine 16.

[0043] The memory stores data used in the process described below.

[0044] In particular, it records a computer application, consisting of computer programs comprising instructions whose execution by the processor allows the computer to implement the method described below.

[0045] At this point, we can define the concept of "powertrain emissions control cycle".

[0046] Such a cycle corresponds to a test protocol allowing the evaluation of a vehicle's pollutant emissions under predetermined driving conditions.

[0047] This is known as the WLTC cycle (from the English "Woldwide Harmonized light Vehicles test Cycles", also called WLTP cycle), which consists of driving a vehicle at four predetermined speeds for 30 minutes, over a distance of 23.2 km and measuring its pollutant emissions. This test is carried out a first time with an initially charged battery, and a second time with an initially discharged battery.

[0048] We also know the RDE cycle (from the English "Real driving emission"). According to this cycle, two test phases are planned, a first phase of driving on open roads, following a predefined route which combines cycles in town, in interurban areas and on motorways, and a second phase of driving on test benches.

[0049] In the remainder of this disclosure, a range of use of the traction battery will be defined as a range of BSOC charge levels within which the traction battery may be used in accordance with the invention and outside of which the charge level must never be found.

[0050] As shown in Figure 2, the theoretical operating range of the traction battery is between a charge level of 0% and a charge level of 100%.

[0051] In practice, the operating range Pu of the traction battery will be between a lower limit BSOCmin and an upper limit BSOCmax distinct from 0 and 100%, so as to guarantee the durability of the battery and a sufficient level of performance.

[0052] In practice, these limits vary according to the outside temperature T ex t and aging of the traction battery.

[0053] Figure 2 shows the variations of these lower bounds BSOCmin and upper limit BSOCmax as a function of the outside temperature T ex t.

[0054] Thus, this figure 2 represents a Carto mapping of these terminals for a given aging state of the battery (here at the start of the battery's life).

[0055] Figure 3 illustrates a similar Cartis map, established for another given aging state of the battery (here at the end of the battery life, i.e. after 15 years of use).

[0056] Although two maps would be sufficient to implement the method described above, more are established here. More precisely, three are established, the third Carts map being established at mid-life of the battery, i.e. after 8 years of use. This third Carts map is not illustrated in the figures.

[0057] Between these three battery ages, a linear interpolation will be performed to determine the battery usage range given the exact age of the battery.

[0058] As shown in Figure 2, the operating range Pu of the 16A traction battery is therefore between two curves illustrating the variations of the lower limit BSOCmin and upper limit BSOCmax as a function of the outside temperature T ex t.

[0059] Between these curves, we will consider different zones I, II, III, IV within which the powertrain will be controlled in different ways, as will be explained in detail below. These four zones are separated by curves which represent intermediate limits BSOC1, BSOC2, BSOC3 and which also vary according to the outside temperature T ex t and the aging state of the traction battery.

[0060] At this stage, we can already specify that zone III corresponds to the preferred range of use of the traction battery, while zones I and IV (and zone II to a lesser extent) correspond to safety ranges within which the battery will remain usable but within which the powertrain will be controlled so as to return the charge level to zone III as much as possible.

[0061] It should be noted that all the terminals illustrated in Figure 2 vary according to the outside temperature Text, between -30°C and 10°C. Above 10°C, they will present constant values ​​identical to those they present at 10°C. We will not be interested here in temperatures below -30°C.

[0062] For simplification, these limits all vary in the form of piecewise affine functions having a first slope between -30°C and -10°C, and a second slope between -10°C and 10°C. Of course, other forms of functions could have been considered, but this form has the advantage of being simple and of providing good results, particularly during powertrain emissions control cycles.

[0063] We can now describe in more detail how the boundaries are defined.

[0064] The lower terminal BSOCmin is such that the accumulator battery 16A is always able to start the internal combustion engine 17, regardless of the outside temperature T ext (provided that the latter is above -30°C). It is therefore not permitted to use the traction battery in the area below this terminal since the available power would not allow the internal combustion engine to be started.

[0065] It turns out that the power available to power the electrical machine 16 decreases when the charge level BSOC of the accumulator battery 16A decreases, when the outside temperature T ex t decreases and when the battery ages.

[0066] This lower bound BSOCmin therefore presents negative and / or harmful steering coefficients.

[0067] To set this lower bound BSOCmin, we use here a first pivot point P1 (see figure 2) from which the segments representing the variation of the lower bound BSOCmin extend.

[0068] This first pivot point P1 corresponds to the charge level required to start the internal combustion engine 17 at the most restrictive outside temperature for this, which here is -30°C.

[0069] In practice, this charge level is chosen so that the traction battery can deliver sufficient electrical power for this start, for a predetermined duration. This power is here at least 3kW for 2 seconds.

[0070] In practice, the BSOC load level of this first pivot point P1 is here: - 57% at the start of life, which allows it to deliver 8kW, - 53% at mid-life, which allows it to deliver 5kW, - 47% at the end of its life, which allows it to deliver 3kW.

[0071] We observe here that the pivot point P1 could, at the beginning and mid-life of the battery, have a lower charge level value. However, it was chosen not to reduce this minimum charge level too much at the beginning of life to preserve the health of the battery as long as possible and so that the battery capacity does not vary excessively during its lifetime. In addition, the high useful BSOC charge level for the battery at the beginning of life makes it possible to increase the overall performance level of the storage battery, thus making it possible to draw more power from discharge.

[0072] The upper limit BSOCmax is set so that using the battery below this limit does not damage it and the battery is always used in a charge level range where it performs well.

[0073] Here the upper bound BSOCmax has a value of approximately: - 85% between -30°C and -10°C, then a value which decreases beyond that, at the start of life and at mid-life, - 80% at -30°C and which increases to 85% at -10°C, then a value which is constant beyond that, at the end of life.

[0074] The BSOC1 terminal, closest to the lower BSOCmin terminal, delimits with it a deactivation zone I.

[0075] The idea is that when the BSOC charge level of the traction battery is in this zone, the computer does everything possible to increase this charge level.

[0076] In practice, in this area, the computer 13 will control the powertrain so that the internal combustion engine 17 drives the electric machine 16 and regenerates the traction battery 16A as soon as possible.

[0077] Furthermore, in this zone, the computer 13 will control the powertrain so as to deactivate at least one convenience function of this powertrain 15 and to leave active at least one primary function of the powertrain 15.

[0078] The electric powertrain makes it possible to offer different functions, some of which are described as convenience and others as primary, in the sense that the primary functions are more important (or even essential) than the convenience functions.

[0079] Typically, a primary function is to enable the electric machine 16 to consume electrical energy stored in the storage battery 16A to start the internal combustion engine, and bring it directly to 1000 rpm before starting the fuel injection 17.

[0080] Other primary functions would be, for example, the function described below of "peak-shaving", the functions known as "overboost", "shifting", and "torque split": assistance from the BSG starter (alternator-starter type) to the internal combustion engine, the end-of-mission recharge function which allows the pollution control function to be carried out on the next trip, the "e-cat" function for supplying heated grilles to the catalytic converter (pollution control function)...

[0081] A convenience function consists, for example, of authorizing the electric machine 16 to consume electrical energy stored in the accumulator battery 16A to propel the vehicle in hybrid mode, in order to provide the vehicle with greater acceleration.

[0082] Other convenience functions would be, for example, the so-called engine lag function (assistance provided by the BSG starter to the internal combustion engine when the latter is running at low rpm (800-2000rpm)), the so-called "ICE restart" function (i.e. rapid restart after the engine has stopped due to a "coasting stop" or "sailing stop" function), the windscreen heating function.

[0083] Thus, in deactivation zone I, the convenience functions can no longer be used, while the primary functions remain usable as needed.

[0084] We thus understand that thanks to the deactivation zone I, when the level of BSOC charge of the 16A traction battery will gradually decrease, the calculator will not abruptly prohibit the use of this battery.

[0085] In practice, the charge level range Ai, which corresponds to the difference between the two terminals BSOCmin and BSOC1, has a constant value whatever the outside temperature T ex t and regardless of the age of the traction battery, which corresponds to an energy quantity of 60 Wh.

[0086] It is also possible to plot the representative curve of the BSOC1 terminal on this basis, for each Carto, Carts, Cartis mapping.

[0087] Terminal BSOC2 delimits a safety margin II zone with terminal BSOC1. The idea is that when the BSOC charge level of the 16A traction battery is in this zone, the computer attempts to increase this charge level when conditions are favorable.

[0088] In practice, in this zone, the computer 13 will control the powertrain 15 so as to regenerate the traction battery 16A by means of the internal combustion engine 17 as soon as favorable conditions are met (in practice, when the internal combustion engine is in a high-efficiency operating range).

[0089] In practice, this safety margin zone II extends over a range AH ​​of charge level such that the 16A traction battery can remain in this zone over the entire RDE cycle, when at the start of this cycle the charge level BSOC was located on the curve representing the BSOC2 terminal.

[0090] To configure the representative curve of the BSOC2 terminal, the following information was then considered.

[0091] The Euro7 regulation is very restrictive but should only apply to outside temperatures above -10°C. One solution to comply with it would be to use the electric machine 16 in engine mode when the operating conditions of the internal combustion engine 17 generate the most polluting emissions. In practice, these conditions occur in particular during a cold start of the engine.

[0092] For example, during such a start, if the driver presses the accelerator in such a way that a power demand of 100kW is required, it can be provided that 90kW is supplied by the internal combustion engine and the remaining 10kW is supplied by the electric machine, which draws its energy from the storage battery. Thus, it is necessary to define to what extent the electric machine 16 must support the internal combustion engine 17 in order to reduce the pollutant emissions of the latter during an RDE cycle. This function is known as "peak-shaving". The aim is to limit the emission of pollutants when this function is activated, after a cold start for example. In this example, the pollutant treatment system is not capable of treating those emitted by the combustion engine. internal when the latter develops 100kW.

[0093] Once these conditions are defined, it is therefore possible to determine the coordinates of a point P2 defined at -10°C (the most restrictive temperature in the Euro7 standard). Here, the ordinate of this point is defined to ensure a discharge at a power of at least 9kW for 10 seconds.

[0094] In practice, the AH range of charge level, which corresponds to the difference between the two terminals BSOC1 and BSOC2, has a constant value whatever the outside temperature T ex t above -10°C and regardless of the age of the battery, which corresponds to an energy quantity of 80 Wh. In this way, the battery will be able to provide a power, at -10°C of: - 14kW at the start of life, - 12kW at mid-life, and - 9kW at the end of its life, which will be lower than desired but sufficient nonetheless.

[0095] Note that this amount of energy will also be constant below the temperature of -10°C on the Carto, Carts maps at the beginning and middle of the battery life, but that it will be increasingly lower when the outside temperature decreases from -10°C to -30°C on the Carts map at the end of the battery life.

[0096] It is also possible to plot the representative curve of the BSOC2 terminal on this basis, for each Carto, Carts, Carts mapping.

[0097] The two terminals BSOC2 and BSOC3 delimit nominal zone III between them.

[0098] This nominal zone III is the one within which we want the BSOC charge level of the traction battery to remain as often as possible since it is in this zone that its performance is the best. In other words, when the 16A traction battery has a BSOC charge level located in this zone, it is possible to control the powertrain in such a way as to reduce the fuel consumption of the internal combustion engine as much as possible.

[0099] Indeed, in this zone, the energy from the regeneration phases using the kinetic energy of the vehicle can then be used to supply the electric machine 16 with current so as to reduce the power that the internal combustion engine 17 must develop.

[0100] In practice, this nominal zone III extends over a range Am of charge level such that the traction battery can remain in this zone over the entire WLTC cycle.

[0101] This range, which corresponds to the difference between the two terminals BSOC2 and BSOC3, has a value which increases with the outside temperature Text, due to pollution control constraints.

[0102] This beach is here: - at the start of life, 141Wh at 10°C, 60Wh at -10°C and 57Wh at -30°C, - at mid-life, 130Wh at 10°C, 56Wh at -10°C and 55Wh at -30°C, - at the end of life, 132Wh at 10°C, 53Wh at -10°C and 53Wh at -30°C,

[0103] It is observed that these values ​​vary little (less than 10%) depending on the age of the battery, but vary greatly with the outside temperature T ex t.

[0104] It is also possible to plot the representative curve of the BSOC3 terminal on this basis, for each Carto, Carts, Cartis mapping.

[0105] The BSOC3 terminal, closest to the upper BSOCmax terminal, delimits with it the safety zone IV.

[0106] This safety zone IV is the one within which we want to modulate regeneration. Indeed, when the BSOC charge level of the battery is high, it may happen that regeneration is no longer possible so as not to go beyond the upper limit BSOCmax.

[0107] In practice, this safety zone IV extends over a range Aiv of charge level, which corresponds to the difference between the two terminals BSOC3 and BSOCmax, and which has a constant value whatever the outside temperature T ex t and whatever the age of the traction battery.

[0108] This gap is 30Wh here. It is chosen as follows.

[0109] When the battery has a BSOC charge level located on the BSOC3 terminal, it must still be possible to recharge the battery during a regeneration phase of a few seconds, here 10 seconds, at a high power (which depends on the characteristics of the vehicle and its powertrain). This power is here at least 8kW. The idea is that the system is capable of absorbing the maximum power value at the end of the WLTC cycle when lifting the foot (the cycle ends with a deceleration from 130 km / h to 0 km / h).

[0110] These data therefore make it possible to define a pivot point P3 at a temperature of 10°C (temperature where recharging is most efficient) allowing these conditions to be satisfied.

[0111] In this way, the battery will be able to receive a power, at 10°C of: - 14kW at the start of life, - 11kW at mid-life, and - 8kW at end of life.

[0112] At this stage, the three maps Carto, Carts, Cartis are therefore well defined.

[0113] We can therefore describe how, in practice, the powertrain 15 is controlled depending on the conditions encountered.

[0114] This process is implemented in a loop, that is, recursively at regular time intervals.

[0115] It involves several stages.

[0116] The first step is for the calculator to acquire an initial temperature data. This could, for example, be the battery temperature, noted T ex t.

[0117] The second step is to acquire a second piece of data relating to the aging of the 16A accumulator battery. As mentioned above, this is the age of the battery.

[0118] The third step is to deduce the Pu usage range of the 16A accumulator battery at this temperature and for this age.

[0119] In practice, here, the calculator 13 begins by acquiring the two maps Carto, Carts, Cartis associated with the ages closest to the age of the battery. For example, if the 16A traction battery has been used for 10 years, the calculator acquires the two maps Carts and Cartis.

[0120] It then reads, in these two maps, the values ​​of the terminals BSOCmin, BSOC1, BSOC2, BSOC3, BSOCmax associated with the outside temperature T ex t measured.

[0121] He can then deduce, by linear regression, the value of these same terminals taking into account the exact age of the battery. In the example above, if the values ​​of the lower limit BSOCmin are 52% in the Carts map and 45% in the Cartis map, the value retained for the lower limit will be 50%.

[0122] Once the battery usage range is well defined by all of these terminals, the computer controls the powertrain 15 differently depending on the zone in which the BSOC charge level of the battery is located.

[0123] As explained above: - in zone I, the convenience functions of the powertrain 15 are deactivated and the battery is regenerated using the internal combustion engine 17 as soon as possible, - in zone II, all functions of the powertrain 15 are activated and the battery is regenerated using the internal combustion engine 17 as soon as the latter is operating in a high-efficiency range, - in zone III, all functions of the powertrain 15 are activated and the powertrain 15 is used to reduce pollutant emissions and consumption of the internal combustion engine as much as possible, and - in zone IV, the regenerative braking function is monitored to ensure that the BSOC charge level does not exceed the upper terminal BSOCmax, and the electric machine 16 is activated in motor mode to reduce this BSOC charge level.

[0124] The present invention is in no way limited to the embodiment described and shown, but those skilled in the art will be able to provide any variation in accordance with the invention.

Claims

CLAIMS

1. Method for controlling a powertrain (15) of a hybrid motor vehicle (10), said powertrain (15) comprising an internal combustion engine (17) and an electric machine (16) supplied with current by a storage battery (16A), the method comprising steps of: - acquisition of initial data relating to a temperature (T ex (t) in or around the motor vehicle (10), - acquisition of a second data item relating to the aging of the accumulator battery (16A), - determination of a usage range (Pu) of the accumulator battery (16A), as a function of the first data and the second data, and - control of the powertrain (15) as a function of the determined range of use (Pu), characterized in that said range of use (Pu) comprises at least two distinct charge level zones (BSOC) of the accumulator battery (16A), including a preferred zone (III) and a lower zone (I), and in that, when the charge level (BSOC) of the accumulator battery (16A) is located in the lower zone (I), the powertrain (15) is controlled by deactivating at least one convenience function of the powertrain (15) and leaving at least one primary function of the powertrain (15) active.

2. A control method according to claim 1, wherein, the electrical machine (16) being adapted to start the internal combustion engine (17), the primary function consists of authorizing the starting of the internal combustion engine (17).

3. A driving method according to claim 1 or 2, wherein the approval function consists of authorizing the electric machine (16) to propel the motor vehicle (10).

4. Control method according to one of claims 1 to 3, in which the second data item comprises the age of the accumulator battery (16A).

5. Control method according to one of claims 1 to 4, in which said determination step is carried out using at least two distinct maps (Carto, Cartis) in each of which a predefined range of use (Pu) varies as a function of the first data only, the two maps (Carto, Cartis) being associated with second distinct data.

6. Control method according to claim 5, in which the range of use (Pu) is determined by reading in at least two maps (Carto, Cartis) limits of the predefined range of use (Pu) associated with the first acquired data, then by calculating limits of the range of use (Pu) as a function of the limits read and the second data.

7. Control method according to one of claims 1 to 6, in which the preferred zone (III) has a lower limit (BSOC2) of charge level (BSOC) which passes through a point (P2) defined such that when said temperature (Text) is -10°C and the accumulator battery (16A) delivers a predetermined power for a predetermined duration, the charge level (BSOC) does not reach the lower zone (I).

8. Control method according to one of claims 1 to 7, in which the preferred zone (III) has an upper limit (BSOC3) of charge level (BSOC) which passes through a point (P3) defined in such a way that when the temperature (Text) outside the motor vehicle (10) is 10°C and the storage battery (16A) receives a predetermined power for a predetermined duration, the charge level initially on the upper limit (BSOC3) does not leave the operating range (Pu).

9. Control method according to one of claims 1 to 8, in which said range of use (Pu) comprises an upper zone (IV) and in which, when the charge level (BSOC) of the accumulator battery (16A) is located in the upper zone (IV), the powertrain (15) is controlled so that the electric machine propels the motor vehicle (10).

10. A driving method according to one of claims 1 to 9, wherein said operating range (Pu) comprises an intermediate zone (II) located between the preferred zone (III) and the zone (I) and wherein, when the charge level (BSOC) of the storage battery (16A) is located in the intermediate zone (II), the powertrain (15) is controlled so that the internal combustion engine (17) recharges the storage battery (16A) when it is in a range of high-efficiency operating points.

11. Hybrid motor vehicle (10), comprising a powertrain (15) which comprises an internal combustion engine (17) and an electric machine (16) supplied with current by an accumulator battery (16A), and a computer (13) programmed to implement a control method according to one of claims 1 to 10.

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