A method for controlling the delivery of electric power from a battery to one or more electric motors of an electric powertrain of a vehicle, particularly during a timed lap of short duration

Abstract

There is described a method for controlling the delivery of electric power from a battery to one or more electric motors of an electric powertrain of a vehicle, for optimally managing the power delivery during a short-duration timed lap.

Description

[0001] "A method for controlling the delivery of electric power from a battery to one or more electric motors of an electric powertrain of a vehicle, particularly during a timed lap of short duration"

[0002] ★★★★

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the Invention

[0005] The present invention relates to the management of electric power in electric powertrains for vehicles, particularly BEV vehicles. More specifically, the invention was developed with reference to the management of the electric power in a competitive driving mode.

[0006] Prior Art

[0007] In the vehicles with an electric powertrain (BEV), the maximum performance of the powertrain is heavily limited by the thermal constraints of the high-voltage battery and of the electric motors. The factor (battery or electric motor (s)) which is more limiting generally depends on the architecture of the high-voltage electric system, but in high-performance vehicles it is generally the battery which constitutes the more limiting factor.

[0008] However, in given driving conditions - for example during a short-duration timed lap on a race track of normal length (3-5 km, for example) the thermal constraints of the battery are generally not a problem, since the duration of the lap - both as regards kilometres and as regards time - is not sufficient to cause problems of performance limitations due to the thermal derating of the components. It should be observed, at any rate, that even during a short-duration timed lap the refrigeration cycle cooling system of the (high-voltage) battery is generally controlled in such a way as to express the maximum cooling power.

[0009] This means that - irrespective of the control strategy adopted for managing the delivery of electric power - in the known solutions the cooling of the high- voltage battery has a higher priority than the propulsive users. Consequently, the power available for propulsion may, in given operational conditions, be far below the maximum, with a negative impact as regards the lap times.

[0010] Object of the Invention

[0011] The invention aims at providing a method for the thermal management of the battery during a short- duration timed lap, which enables increasing the power availability for the propulsive users within a mission comparable to a short-duration timed lap.

[0012] Summary of the Invention

[0013] The object of the invention is achieved by means of a method having the features set forth in the claims that follow, which form an integral part of the technical disclosure provided herein in relation to the invention.

[0014] Brief Description of the Figures

[0015] The invention will now be described with reference to the annexed Figures, which are provided by way of non-limiting example only and wherein:

[0016] - Figure 1 shows a diagram of the electric power vs. the variation of a discharge power of a high-voltage battery of the vehicle,

[0017] - Figure 2 is a double diagram representative of a method according to the invention,

[0018] - Figure 3 shows a state diagram which describes part of a method according to the invention,

[0019] - Figure 4 is similar to Figure 1, but refers to the general implementation of the method according to the invention, and

[0020] - Figures 5, 6, 7 show a time diagram representative of an evolution of the power delivery along a road stretch, particularly a straight stretch of a circuit on the exit of a turn, according to the method according to the invention and in three respective different operational conditions.

[0021] Detailed Description

[0022] The invention relates to a method for controlling the delivery of electric power from a battery to one or more electric motors of an electric powertrain of a motor vehicle. The term "battery" used in the following denotes (even when this is not specified) a high-voltage battery generally used for powering the vehicle, i.e. for supplying both the propulsive users (electric motors) and the non-propulsive users (cooling system of the battery, cooling system of the cabin, etc.). The definition, therefore, does not apply to a possible low- voltage battery for the on-board electric network, which is anyway powered by the same high-voltage battery via a DC-DC converter.

[0023] The method is schematically represented, in a general fashion, in Figure 2 by a state diagram 1 and a logic block for changing the priority 100. They perform the operations of two logic cores of the method according to the invention, which comprise a first logic core for detecting the part of the timed lap instantaneously travelled by the vehicle (diagram 1 - representing a so- called state machine) and a second logic core for variating a priority sequence for delivering an electric discharge power of the battery of the vehicle.

[0024] There are three states described in the diagram of Figure 2, and further detailed in the individual representation of the same graph in Figure 3: a state BRK (block 2) which corresponds to a deceleration maneuver of the vehicle, a state PRF (block 4) which corresponds to an acceleration maneuver of the vehicle, subsequent to the deceleration maneuver BRK a state IDL of general travel (block 6), with or without (positive or negative) acceleration, which may take place both in the state PRF and in the state BRK.

[0025] The states 4, 6 are commonly known as "PL" or "Power Limited" states, while the state 2 is commonly known as "GL", or "Grip Limited" state. While driving on a circuit, the states GL and Pl alternate in the passage from a turn to a straight stretch, and vice versa.

[0026] The sequence of events of interest for the method according to the invention, underlying the diagram of the Figures 2, 3 and shown in the diagrams of the Figures 5 to 7, takes place between two deceleration maneuvers BRK, specifically two braking maneuvers, and therefore may correspond to travelling along a stretch of a road or of a circuit which starts on the exit of a first turn, develops along a straight stretch, or generally along a stretch - between two subsequent turns - which is travelled without any remarkable braking, and ends with a braking preceding a second turn.

[0027] As a further general premise to the description which follows, the technical teaching relating to the invention is set forth with reference to a management based on assigning delivery priorities to the propulsive and non-propulsive users of the vehicle; such an approach is extensively described in the Italian Industrial Invention Patent Application nr. 102024000002938, filed on the same date in the name of the same Applicant.

[0028] In this regard, Figure 1 shows a diagram of delivery of electric power P deliverable from a high-voltage battery of the vehicle as a function of the limit value of the electric discharge power of the battery the latter value deriving as output data from an algorithm for calculating a so-called State Of Power (SOP). The discharge limit generally depends on the SOC (State of Charge), on the temperature and on operational conditions of current and voltage. Moreover, denotes the maximum nominal power which an EAC (Electrical Air Compressor) can absorb from the high- voltage battery for cooling the latter, denotes the power actually used for cooling the high-voltage battery, and denotes the maximum electric power absorbable by the EAC. Generally speaking, it may be assumed that in such a way as to use only the value inthe following discussion. For a further simplification, moreover, it may be assumed that PHVBCOOI coincides with the total consumption of electric power of the high- voltage batteries by non-propulsive users.

[0029] Let be a maximum value of propulsive electric power (i.e. a maximum propulsion power) assigned to a driving mode conceived to handle short- duration timed laps. Such driving mode may be displayed to the user as a "race" mode, and may be one driving mode in a wider set of choices available to the user. By way of example only, the value of is 560 kW . Moreover, let be the maximum of propulsive electric energy, also taking into account the power actually available from the high-voltage battery for the propulsive users.

[0030] Given such premises, a conventional management of the electric power delivery comprises an assignment of delivery priorities which favours the non-propulsive users, and specifically the cooling of the high-voltage battery, which receives a higher priority than the propulsive users.

[0031] It is then possible to define, with a few simplifications, the values of P and as

[0032] (2)

[0033] The formulae (2) and (3) indicate that the cooling of the high-voltage battery has a higher priority than the propulsive users. Such a condition is shown in Figure 1 wherein, in addition to the values set forth in the foregoing, the value appears as well, corresponding to a value of electric discharge powerof the high- voltage battery (which is therefore deliverable by the same battery to the users of the vehicle) which equals the sum of the maximum of the requests by the propulsive users and of the power used by the cooling system of the same high-voltage battery , which is the user having the highest priority.

[0034] As may be observed in the diagram of Figure 1, when the value is reached, the value of immediately drops below the value since, considering the formula (2), it is limited by the power request for cooling the battery which has the highest priority. As assumed in the foregoing, indeed, it is possible to notice that the value remains at the respective maximum value until it is intersected by the power (in proximity of the origin of the axes) .

[0035] If this condition were maintained throughout the timed lap, in the first part thereof - ideally starting from a condition = M, M being equal to the maximum value of the discharge power of the high-voltage battery - it would be possible to satisfy the maximum request of propulsive power and the maximum request of non- propulsive power for cooling the battery. As decreased below the part of propulsive power would be reduced by the value of until reaching the condition wherein equals , which condition corresponds to the inhibition of the propulsion. Without going as far as the latter possibility, it is evident that the reduction of the power allocated to the propulsive users leads to an increase of the lap times. In the view of the foregoing, according to the invention, there is defined a method for controlling the delivery of electric power from a battery to one or more electric motors of an electric powertrain of a vehicle, wherein the method comprises:

[0036] - defining a first priority sequence for a delivery of an electric discharge power oof said battery, comprising assigning a lower priority to the delivery of said electric discharge power of said battery to one or more propulsive users of said vehicle comprising said one or more electric motors of the electric powertrain of the vehicle, and assigning a higher priority to a delivery of said electric discharge power of said battery to one or more non-propulsive users of said vehicle, comprising a refrigeration cycle cooling system of said battery, defining a second priority sequence for the delivery of an electric discharge power of said battery, comprising assigning a higher priority to the delivery of the electric discharge power HVBof the battery to said one or more propulsive users of said vehicle, and assigning a lower priority to the delivery of the electric discharge powero f the battery to said one or more non-propulsive userosf said vehicle, comprising a refrigeration cycle cooling system of said battery, detecting the occurrence of a deceleration maneuver (BRK) of the vehicle, particularly a braking maneuver, detecting the occurrence of an acceleration maneuver (PRF) of the vehicle following said deceleration maneuver (BRK), using the first priority sequence until a predetermined time interval tC_OFF begins,

[0037] - using the second priority sequence, by replacing the first priority sequence therewith, for a predetermined time interval tC_OFF,

[0038] - using the first priority sequence, by replacing the second priority sequence therewith, when said predetermined time interval tC_OFF has elapsed, wherein said predetermined time interval tC_OFF ends at an instant of time tC_OFF_2 following said detecting the occurrence of an acceleration maneuver PRF of the vehicle subsequent to said deceleration maneuver.

[0039] In preferred embodiments of the invention, named

[0040] - the maximum electric discharge power that can be delivered by the battery,

[0041] - mthe maximum nominal value of the maximum electric power that can be delivered to said one or more propulsive users, the maximum electric power that can be delivered to said one or more propulsive users, and

[0042] - the maximum electric power that can be delivered to said refrigeration cycle cooling system of said battery,

[0043] - the electric power actually delivered to said one or more propulsive users,

[0044] - the electric power actually delivered to the refrigeration cycle cooling system of said battery, the first priority sequence is defined by the expressions (2) and (3) already discussed in the foregoing, i.e.: whereas the second priority sequence is defined by the following expressions (4) and (5):

[0045] It can be immediately noted that the expressions (4) and (5) substantially correspond to an inversion of the determination criteria on which the expressions (2) and (3) are based. In the expression (4) - which concerns the calculation of the power delivered to the propulsive users - the argument of the minimum operator comprises two maximum values, since one is a maximum value of power which can be delivered to the propulsive users, and the other is a limit value of the availability of deliverable power. On the contrary, in the expression (2) the argument of the minimum operator comprises a single maximum value , while the second value corresponds to a maximum value minus a part destined to cooling the battery

[0046] In the same fashion, in the expression (5) - which concerns the calculation of the power delivered to the cooling system of the battery - the argument of the minimum operator comprises a single maximum value , whereas the second value is a maximum minus a part destined to the propulsive users In the expression (3), on the contrary, the argument of the minimum operator contains two maximum values, and

[0047] The logic block 100 in Figure 2 exemplifies the management of the priority sequences in the states BRK, PRF, IDL dealt with in diagram 1, according to preferred embodiments of the invention and with reference to the expressions (2), (3) and (4), (5) in question.

[0048] The logic block 100 is essentially represented as a matrix, wherein a first row 102 identifies, for each state BRK, PRF, IDL of diagram 1, the corresponding relationship for determining the value and wherein a second row 104 identifies, again for each state BRK, PRF, IDL of diagram 1, a corresponding relationship for determining the value Consequently, each column of the matrix referring to the states BRK, PRF, IDL identifies the respective set of relationships for determining said values, which corresponds - due to what has been described in the foregoing - to the first priority sequence (phases BRK, IDL - expressions (2), (3)), and to the second priority sequence (phase PRF - expressions (4), (5)).

[0049] The effect of the method according to the invention is clearly shown in Figure 4. In a comparison with Figure 1, Figure 4 immediately shows the effect of the change of the priority sequence: upon reaching the value of discharge power > the electric power that can be delivered to the propulsive users remains equal to the value until the occurrence of the condition i.e. the point wherein the discharge power equals the value This is the effect of the change of the priority sequence implemented by the method according to the invention: the method reduces or takes to zero (the second option being shown in Figure 4) the part of electric power delivered to the refrigeration cycle cooling circuit of the high-voltage battery, which goes - in the instance of Figure 4 - from the value to zero. In this way, it is possible to guarantee a delivery of power to the propulsive users which is extended in comparison to what is observed in the prior art .

[0050] In this regard, referring to the Figures 5 to 7, for the purposes of the method according to the invention there are defined some time intervals associated with the following references:

[0051] - the instants of time t0 and t1 - the instant t1 following the instant t0 - delimit a time interval tBRK during which the deceleration maneuver BRK takes place, which is detected in block 2. Generally speaking, during the interval tBRK the first priority sequence applies, but the extension in time of such validity depends on the actual placement of the occurrence of the start of the predetermined time interval (which will be denoted as tC_OFF in the following) during which the second priority sequence applies.

[0052] Preferably, detecting the occurrence of the deceleration maneuver as per block 2 comprises, alternatively, detecting an actuation of an accelerator pedal GP of a lesser extent than a first threshold of actuation THRRLS, or detecting a brake pedal BP actuation of a greater extent than a second actuation threshold THRBP. Both thresholds are marked in Figure 2 and in Figure 3;

[0053] - the instants of time t1 and t2 - the instant t2 following the instant t1 - delimit the time interval tPRF described in the foregoing, during which the second priority sequence applies. The instant t1 substantially marks the boundary between the deceleration maneuver BRK and the acceleration maneuver PRF detected at block 4. Preferably, detecting the occurrence of the acceleration maneuver PRF of the vehicle comprises detecting an actuation of the accelerator pedal GP of a greater extent than a third actuation threshold THRGP, wherein the third actuation threshold is of a greater extent than the first actuation threshold THRRLS;

[0054] - the instants of time t2 and t3 - with the instant t3 following the instant t2 - delimit the time interval tIDL, which corresponds to an interval of general travelling IDL wherein the first priority sequence applies again, i.e. a time interval wherein the delivery of electric power to the cooling system of the battery of the vehicle has a priority higher than the delivery of electric power to the propulsive users;

[0055] - the instants of time t3 and t4 - the instant t4 following the instant t3 - delimit a new time interval tBRK associated with a new deceleration maneuver BRK, detected according to the same procedure as per block 2;

[0056] - the instants of time tC_OFF_l and tC_OFF_2 - the instant tC_OFF_2 following the instant tC_OFF_l - delimit the predetermined time interval tC_OFF during which the second priority sequence applies.

[0057] The time interval tC_OFF ends tC_OFF_2 at an instant of time after detecting the occurrence of an acceleration maneuver PRF of the vehicle following the deceleration maneuver BRK, and therefore the instant tC_OFF_2 always follows the instant t1. According to preferred embodiments of the invention, the instant tC_OFF_2 coincides with the instant t2, so that the validity of the second priority sequence ends with the conclusion of the phase PRF (this is the condition shown in the Figures).

[0058] Generally speaking, however, it is anyway possible to make the instants tC_OFF_2 and t2 independent from each other, for example if the duration of the interval PRF requires an adaptation (with an extension or a reduction with respect to what would be determined only by the placement of the instant tC_OFF_2, for example in order to enable the execution, according to needs, of other interventions to improve the performances, since the interval PRF corresponds to a phase PL with a higher time gain in the lap.

[0059] The starting instant tC_OFF_l may be variably placed in time, as a function of different needs and circumstances. In a preferred embodiment, the time interval tC_OFF starts ad an instant of time tC_OFF_l corresponding to the instant t1, and thus corresponding to detecting the occurrence of an acceleration maneuver PRF of the vehicle following the deceleration maneuver BRK.

[0060] However, if there is a need to extract as much power as possible for propulsion, then the placement of the instant tC_OFF_l in correspondence with the instant t1 may not be optimal, since the compressor EAC of the refrigeration cycle system requires 2-3 seconds in order to stop, while it continues to absorb electric power which is therefore subtracted from the propulsion. For this reason, it is possible to anticipate the start of the interval tC_OFF by placing it at an instant of time between detecting the occurrence of a deceleration maneuver BRK of the vehicle - i.e., the instant t0 - and detecting the occurrence of an acceleration maneuver PRF of the vehicle - i.e. the instant t1 (t0 < tC_OFF < t1).

[0061] Moreover, it is possible to further anticipate the instant tC_OFF_l by selecting it as coinciding with the instant t0, therefore with the detection of the occurrence of a deceleration maneuver BRK of the vehicle. In this way, it is possible to set the system for the maximum delivery of propulsive electric power already at the detection of a deceleration maneuver.

[0062] There will now be described a single maneuver, which covers the sequence of the states BRK-PRF-IDL-BRK represented in diagram 1, in three distinct operating conditions: -

[0063] >

[0064] >

[0065] For each maneuver, let us moreover assume that:

[0066] - tC_OFF1 coincides with t1 - tC_OFF2 coincides with t2: as a consequence, the duration of the interval tC_OFF is equal to the duration of the phase PRF (a condition which generally corresponds to the preferred embodiments).

[0067] As shown in diagram 1 with the reference INIT, when the driving mode for short-duration timed laps is activated, the initialization condition always corresponds to BRK. This is due to the fact that, as it is clear from the description in the foregoing, the method according to the invention always starts (or repeats itself) from the detection of a deceleration maneuver of the vehicle.

[0068] At the instant t0 (state BRK, block 2) the vehicle approaches a turn, with the concomitant deceleration maneuver BRK, which corresponds to a release of the accelerator pedal GP (GP < THRRLS) and / or to an actuation of the brake pedal BP (BP > THRBP). The references GP and BP are associated with the respective curves of evolution in time of the Figures 5 to 7. At the instant t1, the vehicle starts the maneuver for exiting the turn, by means of the actuation of the accelerator pedal GP (GP > THRGP), which causes the detection of the acceleration maneuver PRF at the block 4. The instant t1 marks the start of the logic of temporary variation of the priority sequence as per the method according to the invention: the reference PC1 / 2, which is associated with an arrow in thicker lines, denotes the replacement of the first priority sequence (expressions (2) and (3)) with the second priority sequence (expressions (4) and (5)) in the transition from the state BRK to the state PRF.

[0069] At the instant t2 which, as regards the position of the vehicle along the circuit, corresponds to travelling along a straight stretch following a stretch immediately after the exit from the turn, when the transition from BRK to PRF takes place, the phase PRF ends and at the same time the first priority sequence (expressions (2) and (3)) is restored, with the replacement PC2 / 1. At this instant, the state determined according to the diagram 1 evolves from PRF to IDL via the node N_PRF. The state IDL is kept until the instant of time t3, when a new transition takes place to the state BRK (node N_BRK), without varying the priority sequence. This is exemplified by the conditions GP < THRRLS or BP > THRBP, which take place at the occurrence of a (new) deceleration maneuver. In other words, the phase IDL is followed by a new deceleration maneuver BRK (instant t3), which ends (instant t4) in a new acceleration maneuver of the vehicle, with the repetition of the method according to the invention.

[0070] It shall be borne in mind that the same conditions GP < THRRLS or BP > THRBP may lead - although this is not shown in the diagrams of the Figures 5 to 7 - to a direct transition from the state PRF to the state BRK (with a direct passage from the node N_PRF to the node N_BRK); this generally occurs in very short straight stretches, wherein the travelling time of the straight stretch is lower than tc 0FF. Moreover, it is possible to go directly to the state IDL through the node N_IDL if one of the following conditions occurs: t1-t0 > BRKtimeout or t4-t3 > BRKtimeout, i.e. if the state BRK determined by the corresponding conditions of the brake pedal and / or the accelerator pedal lasts for an excessively long time. This aims at preventing an unauthorized exploitation of the driving mode envisaged for short-duration timed laps, since such a mode, when it is kept active even if it is not strictly necessary - may cause, on the long term, significant thermal loads on the high-voltage battery. Specifically, the reference BRKtimeout denotes a threshold with an adjustable duration for the occurrence of the conditions which determine the state BRK. In other words, if the conditions which determine the state BRK (GP < THRRLS or BP > THRBP) occur for a time interval t1-t0 or t4-t3 (see Figure 3) greater than BRKtimeout, the driving mode for short-duration timed laps implementing the method according to the invention is disabled in favour of other driving modes, and the logic state shifts to a general travelling mode (IDL) while keeping the refrigeration cycle cooling circuit active, thus cooling the high- voltage battery, and while always applying the first priority sequence.

[0071] The sequence of the states and the transition between states as described in the foregoing are the same in all diagrams of Figures 5 to 7. What varies is the distribution of the discharge poweorf the high- voltage battery between the propulsive users and the cooling system of the battery of the vehicle, due to the temporary change of the priority sequence.

[0072] In the case of Figure 5, wherein the discharge power of the high-voltage battery is greater than or equal to the value throughout the maneuver, the change of the priority sequence does not cause any practical effect, since it is always possible to guarantee a delivery which covers both the request of the propulsive users and the request which is at most equal toof the refrigeration cycle cooling system of the high-voltage battery. Starting from t0, the discharge power experiences an initial increase until the instant t1, which is due to the regeneration operating mode of the one or more electric traction motors in the deceleration and / or braking phase (BRK). This is followed by a progressive decrease until t3, then by a new increase due to the new deceleration / braking maneuver BRK between t3 and t4. The discharge power never crosses the maximum value , and the power delivered to the propulsive users may have a maximum value which remains at so that the power remains at the value substantially throughout the phases PRF and IDL (with the exception of short transitions at the beginning of the former and at the end of the latter). The power PHVBCOOI may equally show a maximum which remains at the value so that the power PHVBCOOI remains at the value throughout the sequence of phases from t0 to t4.

[0073] Considering the formulae (4) and (5) which start being applied at the instant t1, with they become which correspond to the same results as the expressions (2) and (3)

[0074] Substantially, if the conditions are met wherein the effect of the priority change is zero, which corresponds to a situation without a priority change. This means that the temporary priority inversion between propulsive users and the cooling system of the battery leads to an alteration of priorities which however has no impact on the respective power deliveries, since the availability of discharge power enables satisfying all the maximum values requested, irrespective of the priority.

[0075] In the case of Figure 6, wherein the discharge power of the high-voltage battery is comprised between the values least a part of the maneuver, the change of the priority sequence PC1 / 2 has a nearly immediate effect on the cooling system of the battery, and a retarded effect on the propulsive users. The phrase "for at least a part of the maneuver" recalls the fact that the window of power values defined by the extremes and is very small, considering the values at stake, which leads to an excursion of the discharge power PHVB below the value

[0076] Starting from t0, the discharge power has an initial increase (from values lower than in the diagram, but the condition is only temporary) until the instant t1, which is due to the regeneration operating mode of the one or more electric traction motors in the phase of deceleration and / or braking (BRK). There follows a progressive decrease until t3, and then a new increase due to the new maneuver of deceleration / braking BRK between t3 and t4.

[0077] The instant t1 marks the occurrence of the change of the priority sequence, with the passage from the first to the second sequence. When the second sequence applies, the power starts being reduced at an instant t1A

[0078] > t1, when the condition is verified, beyond which - according to the expression (5) - the maximum power passes from the value to with pAfurther reduction of the power is brought about, always due to the temporary change of the priority sequence, when the power reaches the maximum value at an instant t1B

[0079] > t1A. The reduction is progressive - in the Figure, with a lower rate than the reduction which occurs from t1 to t1A - until reaching the zero value at an instant t1C, with t1B < t1C < t2, when the condition is verified. At this point, the evolution of the discharge power may only proceed towards values less than thus to values for which, in the phases PRF and IDL, wherein the request on the accelerator pedal amounts to 100%, the condition is verified. As a consequence, the expressions (4) and (5) become

[0080] At the instant t2 the phase PRF ends, and the first priority sequence PC2 / 1 is restored, wherein the expressions (2) and (3) apply. The diagram in Figure 6 immediately shows the effect of the change of priority: the maximum value goes back to the value and is kept at the maximum value , since IDL is a phase which generally follows disabling the operation of the cooling system, and is characterized by a maximum power request for the wheels; therefore, the cooling of the battery shall generally be at its highest.

[0081] The consequence is that the maximum value (and consequently the power which equals the same maximum value, since the request on the accelerator pedal GP is still 100%), is reduced to the value wherein, particularly in the Figure, holds true. By using the expressions (2) and (3) there is obtained:

[0082] Finally, the power becomes zero as the accelerator pedal is released and a new deceleration / braking maneuver starts, at about the instant t3.

[0083] In the instance of Figure 7, wherein the discharge powero f the high-voltage battery is lower than the value throughout the maneuver from t0 to t4, once again the change of the priority sequence PC1 / 2 has a nearly immediate effect on the cooling system of the battery.

[0084] Starting from t0, the discharge power experiences an initial increase (from values lower than in the diagram, and without ever exceeding the value until instant t1, which is due to the regeneration operating mode of the one or more electric traction motors in the phase of deceleration and / or braking (BRK). There follows a progressive decrease until t3, then a new increase due to the new deceleration / braking maneuver BRK between t3 and t4.

[0085] The instant t1 marks the change of the priority sequence PC1 / 2, with the passage from the first to the second sequence. When the second sequence applies, the power used at the maximum value P starts being reduced at the instant t1A > t1, at which the condition is verified, beyond which - according to the expression (5) - the maximum value of power goes from the value However, in such a condition and while the second priority sequence applies, always holds true, and therefore the value of the power is immediately reduced to zero, which is reached at an instant t1C' with t1A < t1C' < t1B. Generally speaking, the placement in time of the instant t1C' may depend on the disabling dynamics of the compressor EAC.

[0086] With reference to the expressions (4) and (5):

[0087] At the instant t2, the phase PRF ends and the first priority sequence is restored, PC2 / 1; the expressions (2) and (3) apply. Again, the diagram in Figure 7 clearly shows the effect of the change of priority: the maximum value goes back to the value is kept at the maximum value , since IDL is a phase which generally follows disabling the operation of the cooling system, and is characterized by a maximum power request for the wheels, and therefore the cooling of the battery shall generally be at its highest.

[0088] Therefore, the maximum value (and as a consequence, the power which amounts to the same maximum value, since the request on the accelerator pedal is still at 100%) is reduced to the value By using the expressions (2) and (3) there is obtained:

[0089] Finally, the power becomes zero at the release of the accelerator pedal and at the start of a new deceleration / braking maneuver around the instant t3.

[0090] Thanks to the method according to the invention and thanks to the change of the priority sequence of power delivery, it becomes possible to maximize the performance of the vehicle during a short-duration timed lap, by drawing further power - for a time tC_OFF which is limited and defined during calibration - from the cooling system of the high-voltage battery, without incurring in phenomena of thermal overload or thermal drift of the battery. Substantially, the invention operates on the basis of the operational assumption that 1 kW of power used on the exit of a turn (end of a phase GL and beginning of a phase PL) gives a significantly higher benefit in terms of lap times than could be provided by 1kW invested at the end of a straight stretch (end of a phase PL and beginning of a phase GL). This is accomplished according to the fashion described in the foregoing.

[0091] Of course, the implementation details and the embodiments may amply vary with respect to what has been described and illustrated, without departing from the extent of the present invention, as defined in the annexed claims.

Claims

CLAIMS1. A method for controlling the delivery of electric power from a battery to one or more electric motors of an electric powertrain of a vehicle, the method comprising :- defining a first priority sequence for a delivery of an electric discharge power of said batterycomprising assigning a lower priority to the delivery of said electric discharge powerof said battery to one or more propulsive users of said vehiclecomprising said one or more electric motors of the electric powertrain of said vehicle, and assigning a higher priority to a delivery of said electric discharge power of said battery to one or more non-propulsive users (of said vehicle comprising a refrigeration cycle cooling system of said battery, defining a second priority sequence for the delivery of an electrical discharge power of saidbattery comprising assigning a higher priority to the delivery of the electrical discharge powerof the battery to said one or more propulsive users ofsaid vehicle, and assigning a lower priority to the delivery of the electrical discharge powerof the battery to said one or more non-propulsive usersof said vehicle comprising a refrigeration cycle cooling system of said battery, detecting the occurrence of a deceleration maneuver (BRK) of the vehicle, particularly a braking maneuver, detecting the occurrence of a vehicle acceleration maneuver (PRF) following said deceleration maneuver (BRK), using the first priority sequence until a predetermined time interval begins,- using the second priority sequence, by replacingthe first priority sequence therewith, for said predetermined time interval,- using the first priority sequence, by replacing the second priority sequence therewith, when said predetermined time interval has elapsed,wherein said predetermined time intervalends at an instant of time following saiddetecting (ti) the occurrence of an acceleration maneuver (PRF) of the vehicle subsequent to said deceleration maneuver (BRK).

2. The method according to claim 1, wherein, named- the maximum electrical discharge power thatcan be delivered by the battery,- a maximum nominal value of the maximumelectrical power that can be delivered to said one or more propulsive users,- the maximum electrical power that can bedelivered to said one or more propulsive users, and-the maximum electrical power that can be delivered to said refrigeration cycle cooling system of said battery,-the electrical power actually delivered to said one or more propulsive users,-the electrical power actually delivered to said refrigeration cycle cooling system of said battery,-the maximum electric power that can be absorbed by a compressor refrigeration cycle cooling system of said battery, in the first priority sequence, the following relationship applies:and in the second priority sequence the following relationship applies:

3. The method according to claim 1 or claim 2, wherein said predetermined time intervalbegins at an instant of time corresponding to saiddetecting (to) the occurrence of an acceleration maneuver (PRF) of the vehicle subsequent to said deceleration maneuver (BRK).

4. The method according to claim 1 or claim 2, wherein said predetermined time interval (tcOFF) begins at an instant of time corresponding to saiddetecting (to) the occurrence of a deceleration maneuver (BRK) of the vehicle, in particular a braking maneuver.

5. The method according to claim 1 or claim 2, wherein said predetermined time intervalbegins at an instant of timebetween said detecting (to) the occurrence of a deceleration maneuver (BRK) of the vehicle and said detecting (ti) the occurrence of an acceleration maneuver (PRF) of the vehicle subsequent to said deceleration maneuver (BRK).

6. The method according to any one of the preceding claims, wherein said detecting the occurrence of a deceleration maneuver (BRK) of the vehicle comprises, alternatively or in combination:- detecting an actuation of an accelerator pedal (GP) of a lesser extent than a first threshold of actuation ,detecting a brake pedal (BP) actuation of a greater extent than a second actuation threshold (THRBP).

7. The method according to any one of the preceding claims, wherein said detecting the occurrence of a vehicle acceleration maneuver (PRF) comprises detecting an actuation of an accelerator pedal (GP) of an extent greater than a third actuation threshold , whereinthe third actuation threshold is greater than afirst actuation threshold .

8. The method according to any one of claims 2 to 7, comprising continuously maintaining operation of the refrigeration cycle cooling system configured to cool the vehicle battery if the maximum electrical discharge power that can be delivered by the batteryhas a value greater than or equal to a threshold discharge power value at whichoccurs.

9. The method according to any one of claims 2 to 7, comprising. reducing or disabling the operation of the refrigeration cycle cooling system configured for cooling of said vehicle battery during said predetermined time interval if the maximumelectrical discharge power that can be delivered by said batteryHVB has a value less than a threshold discharge power valueat which occurs,- enabling the operation of the refrigeration cycle cooling system configured to cool the vehicle battery after said predetermined time interval has elapsed.

10. The method according to claim 9, comprising disabling operation of the refrigeration cycle cooling system configured for cooling said battery of the vehicle during said predetermined time interval if

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