Control of an automotive belt-driven starter generator

Abstract

An automotive control software that can be loaded in and executed by automotive electronic processing resources (1) and designed to cause, when executed, the automotive electronic processing resources (1) to become configured to control an automotive starter generator (2) operatively coupled to a combustion engine (3) of an automotive hybrid propulsion unit to split the mechanical torque required to the automotive hybrid propulsion unit between the combustion engine (3) and the automotive starter generator (2). In order to split the delivered torque required to the automotive hybrid propulsion unit, the automotive control software is designed to cause, when executed, the automotive electronic processing resources (1) to become configured to calculate different benefit indexes associated with different possible operating conditions of the automotive starter generator (2); each benefit index is calculated based on a quantity representative of a torque delivered and / or on an electric current absorbed by the automotive starter generator (2) in the respective operating condition and is indicative of a benefit in terms of fuel saving obtainable in said operating condition in relation to a variation in the consumption of electrical energy absorbed by the automotive starter generator (2) in the respective operating condition with respect to a reference operating condition thereof. Furthermore, the automotive control software is designed to cause, when executed, the automotive electronic processing resources (1) to become configured to determine a quota of the torque required to the automotive hybrid propulsion unit to be delivered by the automotive starter generator (2) based on the benefit indexes and control the automotive starter generator (2) to make it deliver the determined torque quota attributed to it.

Description

[0001] CONTROL OF AN AUTOMOTIVE BELT-DRIVEN STARTER GENERATOR

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This Patent Application claims priority from Italian Patent Application No. 102023000013683 filed on June 30, 2023, the entire disclosure of which is incorporated herein by reference.

[0004] TECHNICAL FIELD OF THE INVENTION

[0005] The present invention relates to the control of an automotive starter generator. In particular, the invention relates to the control of an automotive belt-driven starter generator in order to split the mechanical torque required to the hybrid propulsion unit between a combustion engine and the automotive starter generator.

[0006] STATE OF THE ART

[0007] As is known, motor vehicles with hybrid propulsion and with completely electric propulsion are provided with electric propulsion units composed of reversible electric machines which are capable of operating as electric motors for generating mechanical torques which are transmitted to the wheels of the motor vehicles for providing the latter with the propulsion and which, in the motor vehicles with hybrid propulsion, can be additional or alternative to those generated by the combustion engines, depending on their greater or smaller electric power (mild hybrid vs. classic hybrid propulsion), and electric generators for producing the so-called regenerative braking or energy recoveries, during which the kinetic energy of the motor vehicles in the braking phase is converted into electrical energy, which is then stored in specially provided electrical energy storage batteries (electric batteries) of the motor vehicles to then be subsequently utilized by the electric machines when they operate as electric motors for providing the motor vehicles with the propulsion.

[0008] For example, in a motor vehicle with a mild hybrid propulsion, the reversible electric machine is composed of a reversible alternator, commonly known as Belt-driven Starter Generator (BSG) or Integrated Starter Generator (ISG), which is a motor generator operatively coupled to a combustion engine of the hybrid propulsion unit by means of a drive belt and can be electronically controlled for selectively operating as electric motor for generating a mechanical torque with which the combustion engine is to be provided and as traditional alternator for generating electrical energy, and in particular for operating as boost (+ 2 mechanical kW and +20 Nm to the drive shaft) for the combustion engine so as to assist it when there is need, as regenerator (5 electric kw) for recharging a 13.6 V battery by means of a high-efficiency energy recovery, as start and stop and for implementing a sailing function for sailing when in release, with gearbox in neutral if necessary, the combustion engine turns off. In this manner, it is possible to cover all the phases of less efficiency of the combustion engine simultaneously reducing consumption and pollution.

[0009] It is known to split the mechanical torque required to the hybrid propulsion unit between the combustion engine and the BSG as a function of the energy losses of the motor vehicle calculated based on parameters relative to the combustion engine, to the BSG and to the electric battery of the motor vehicle.

[0010] OBJECT AND SUMMARY OF THE INVENTION

[0011] The Applicant has been able to observe that the solutions according to the prior art, although satisfactory in some respects, are open to improvements in others.

[0012] The object of the present invention is thus to put at disposal a control software of an automotive BSG / ISG which allows improving the solutions of the prior art, in particular with regard to the efficiency of the overall energy exploitation of the motor vehicle.

[0013] According to the present invention, a control software of an automotive BSG / ISG is put at disposal, as claimed in the appended claims.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 shows a functional block diagram of an electronic control unit of an automotive BSG / ISG according to an embodiment of the present invention.

[0016] Figure 2 shows a more detailed functional block diagram of one of the functional blocks illustrated in Figure 1.

[0017] Figure 3 illustrates a more detailed functional block diagram of another one of the functional blocks of Figure 2 according to an embodiment of the present invention.

[0018] Figure 4 shows a calibration map of the reference electric current for determining values of a reference electric current and a calibration map of the energy losses used for determining values of the energy losses of the motor vehicle according to an embodiment of the present invention. DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0019] The present invention will now be described in detail with reference to the accompanying figures for enabling a person skilled in the art to manufacture it and utilize it. Various modifications to the described embodiments will be immediately evident for the persons skilled in the art and the described general principles can be applied to other embodiments and applications without thereby departing from the scope of protection of the present invention, as defined in the appended claims. Therefore, the present invention is not to be considered limited to the described and illustrated embodiments, but is to be granted the broadest scope of protection in accordance with the described and claimed characteristics.

[0020] Unless otherwise defined, all the technical and scientific terms utilized herein have the same meaning commonly utilized by persons of ordinary skill in the field pertaining to the present invention. In case of conflict, the present description, comprising the definitions provided, shall be binding. Furthermore, the examples are provided for illustrative purposes only and as such are not to be considered limiting.

[0021] In particular, the block diagrams included in the accompanying figures and described in the following are not to be understood as representation of the structural characteristics, i.e. constructive limitations, but are to be interpreted as representation of functional characteristics, that is intrinsic properties of the devices and defined by the obtained effects, i.e. functional limitations, and which can be implemented in different manners, thus so as to protect the functionalities thereof (possibility to operate).

[0022] In order to facilitate the understanding of the embodiments described herein, reference will be made to some specific embodiments and a specific jargon will be utilized for describing them. The terminology utilized in the present document has the purpose to describe only particular embodiments, and is not intended for limiting the scope of the present invention.

[0023] Figure 1 shows a functional block diagram of an automotive electronic control unit 1 in which an automotive control software is stored and executed, the latter being designed to cause, when executed by the automotive electronic control unit 1, in order to split a mechanical torque required to the hybrid propulsion unit between a combustion engine 3 and an automotive starter generator 2, the automotive electronic control unit 1 to become configured to control the automotive starter generator 2, in the following indicated for brevity by the acronym BSG 2, operatively coupled to the combustion engine 3 of an automotive hybrid propulsion unit, usually by means of an automotive drive belt, in the manner described in the following. In particular, the automotive electronic control unit 1 is configured to control the automotive starter generator 2 for making it deliver a determined torque quota attributed to it.

[0024] With regard to the splitting of the mechanical torque required to the hybrid propulsion unit between the combustion engine 3 and the automotive starter generator 2, it is highlighted that what matters on board the motor vehicle are the operations which have to be implemented for producing such functionality and not the hardware and software architectures with which such operations are implemented, to the extent that these could be implemented by means of a concentrated architecture, i.e. by one single automotive electronic control unit 1, or by means of a distributed cooperative architecture, i.e. distributed between different automotive electronic control units in communication and cooperating with one another, depending on the hardware and software architectures that the automotive manufacturer will deem suitable to adopt for implementing such functionality.

[0025] In particular, the automotive electronic control unit 1 is configured to generate a torque command for the BSG 2 indicative of the torque that the BSG 2 has to deliver, based on overall energy losses of the motor vehicle 1 in respective operating conditions of the BSG 2, in which the BSG 2 is required to deliver respective torques. The automotive electronic control unit 1 is configured to determine such possible operating conditions executing a software module which refers to block 9.

[0026] More specifically, the automotive electronic control unit 1 is configured to calculate each of the overall energy losses (block 4, 6) of the motor vehicle 1 in the corresponding operating condition of the BSG 2 based on, in particular as arithmetic or weighted sum, a corresponding energy loss, in the following for descriptive convenience identified by the adjective objective (block 8), indicative of all the real energy losses which take place on the motor vehicle in the corresponding operating condition of the BSG 2, for example due to the mechanical frictions, on the heat losses in the various automotive systems, electrical energy losses in the form of heat which occur during the transmission of electric current through the wires etc., and on a corresponding energy loss, in the following for descriptive convenience identified by the adjective subjective. In particular, the subjective energy losses are calculated (block 7) based on an innovative property criterion which is described in the following with reference to Figures 2 and 3 and the role of which is to represent a factor which positively or negatively influences, in particular to increase or reduce, the role carried out by the objective energy losses in splitting the torque required to the hybrid propulsion unit between the combustion engine 3 and the reversible electric machine and, consequently, in generating the relative torque command for the BSG 2.

[0027] Figure 2 shows a more detailed functional block diagram of how the subjective energy losses are calculated. According to what is shown in Figure 2, the automotive electronic control unit 1 is configured to:

[0028] - calculate different benefit indexes associated with different possible operating conditions of the BSG 2, in which each benefit index is calculated based on a quantity representative of the torque delivered and / or on the electric current absorbed by the BSG 2, in the same time unit, and in the respective operating condition; and is indicative of a benefit in terms of, and determined based on, the fuel saving obtainable in said operating condition, in relation to the variation in the consumption of electrical energy absorbed by the BSG 2 in the same operating condition with respect to a reference operating condition thereof, conveniently, a condition of non-operation of the BSG 2 (block 10); in particular, an operating condition in which the BSG 2 does not deliver torque in output or delivers a null torque;

[0029] - calculate the subjective energy losses (block 12) based on the calculated benefit indexes and conveniently also on the charge status of the battery module.

[0030] In particular, each benefit index is calculated (with reference to block 11) as ratio between the variation in the fuel consumption of the combustion engine 3, expressed for example in milligrams per combustion (mgcc), and the variation in the electrical energy consumption of the BSG 2, expressed for example in milliampere per hour (mAh), between the operating condition associated with the benefit index and the reference operating condition.

[0031] Each variation in the fuel consumption of the combustion engine 3 and of the electrical energy consumption of the BSG 2 are in turn calculated, in a known manner and thus not described in detail, based on the electric current absorption of the BSG 2 for generating torque split to it in the respective operating condition and on the corresponding fuel consumption of the combustion engine 3 for generating the torque split to it in the same operating condition of the BSG 2, all this with respect to the electric current absorption of the BSG 2 and of the fuel consumption of the combustion engine 3 in the reference operating condition.

[0032] In particular, a benefit index is calculated by means of the following formula: , . delta_fuel_saving

[0033] Jdelta_electrical_energy_spent where:

[0034] - benefit is the benefit index;

[0035] - delta _Juel_saving is the variation in the fuel consumption of the combustion engine 3 with respect to the reference operating condition of the BSG 2; and

[0036] - delta_electrical_energy_spent is the variation in the electrical energy consumption of the BSG 2 with respect to the reference operating condition of the BSG 2.

[0037] Figure 3 shows a more detailed functional block diagram of how the subjective energy losses are calculated based on the calculated benefit indexes and on the charge status of the electric battery module.

[0038] According to what is shown in Figure 3, the automotive electronic control unit 1 is configured to:

[0039] - calculate values of a reference electric current representative of the electric current absorption of the BSG 2 (block 13) in different possible operating conditions thereof based on a calibration map of the reference electric current 16 containing different values of the reference electric current as a function of the benefit index and of the electric charge status of the battery module; and

[0040] - calculate values of the subjective energy losses associated with the various operating conditions of the BSG 2 (block 15) based on a calibration map of the subjective energy losses 17 containing different values thereof as a function of the electric charge status of the battery module and of the difference between the electric current absorbed by the BSG 2 and the calculated reference electric current (block 14) for the various operating conditions of the BSG 2.

[0041] As is shown in Figure 4, the calibration map of the reference electric current, indicated by reference numeral 16, comprises:

[0042] - a relatively low state-of-charge area 16A, in which the values of the reference electric current are relatively low; in detail, they have been defined null, i.e. it is not intended for the BSG to deliver torque;

[0043] - a relatively high state-of-charge area 16C, in which the values of the reference electric current are relatively high; this is due to the fact that it is not intended to add a subjective loss to the calculation which would limit the torque split to the BSG and, optionally, - an intermediate state-of-charge area 16B with values between those of the relatively low state-of-charge area 16A and the relatively high state-of-charge area 16C, in which the reference electric current values are intermediate between those of the relatively low state-of-charge area 16A and the relatively high state-of-charge area 16C.

[0044] In particular, the area 16B with intermediate state-of-charge values of the reference electric current calibration map 16 comprises:

[0045] - a relatively low-benefit-index sub-area 16BA, in which the values of the reference electric current are relatively low, in particular are defined null, analogously to those of the area with relatively low state of charge 16A, for preventing from using the BSG in an energetically non-convenient condition;

[0046] - a relatively high-benefit-index sub-area 16BC, in which the reference electric current values are relatively high, in particular analogously to those of the area with relatively high state of charge 16C and in order not to add, to an objective loss, a subjective loss; and, optionally

[0047] - an intermediate-benefit-index sub-area 16BB between those in the sub-areas with relatively low benefit index 16BA and relatively high benefit index 16BC, in which the reference electric current values are intermediate between those in the subareas with relatively low benefit index 16BA and relatively high benefit index 16BC, in particular they progressively increase as the benefit index values increase, for progressively modulating the torque to be split to the BSG.

[0048] Still with reference to Figure 4, the calibration map of the subjective energy losses, indicated by reference numeral 17, comprises:

[0049] - an area with relatively high energy loss values 17A for negative differences between the reference electric current determined for the given operating condition and the corresponding electric current absorbed by the BSG 2;

[0050] - an area with relatively low energy loss values 17B, in particular null values, for positive differences between the reference electric current determined for the given operating condition and the corresponding electric current absorbed by the BSG 2.

[0051] Finally, with reference again to Figure 1, the automotive electronic control unit 1 is configured to determine, in particular calculate, a quota of the torque required to the automotive hybrid propulsion unit to be delivered by the BSG 2, based on the values of the calculated subjective energy losses in the different possible operating conditions of the BSG 2 and on the corresponding values of the calculated objective energy losses in the same operating conditions of the BSG 2; in particular, based on the sum between the values of the objective losses of the motor vehicle and the values of the subjective energy losses of the motor vehicle (block 6 of Figure 1).

[0052] In particular, the automotive electronic control unit 1 is configured to select the quota of the torque to be delivered by the BSG 2 from the possible torque values of the BSG 2 based on which the benefit indexes have been calculated; in particular, so that the selected torque value is associated with the minimum of the different values indicative of the energy losses of the motor vehicle (block 5 of Figure 1).

[0053] Based on what described above, the advantages that the present invention allows achieving are evident. The automotive control software is designed to cause, when executed, the automotive electronic control unit 1 to become configured to control the BSG 2 so as to absorb and consume electrical energy of the battery module only in the case where the benefit, understood as the fuel saving per unit of absorbed electrical energy, is greater than a predefined benefit value. Therefore, the automotive electronic control unit 1 is configured to implement a strategy which allows optimizing the electrical energy consumption of the battery module, consequently improving the effectiveness of the automotive system and the splitting of torque performed between the combustion engine 3 and the BSG 2.

Claims

CLAIMS1. An automotive control software that can be loaded in and executed by automotive electronic processing resources (1) and designed to cause, when executed, the automotive electronic processing resources (1) to become configured to control an automotive starter generator (2) operatively coupled to a combustion engine (3) of an automotive hybrid propulsion unit to split the mechanical torque required to the automotive hybrid propulsion unit between the combustion engine (3) and the automotive starter generator (2); in order to split the delivered torque required to the automotive hybrid propulsion unit, the automotive control software is designed to cause, when executed, the automotive electronic processing resources (1) to become configured to:- calculate different benefit indexes associated with different possible operating conditions of the automotive starter generator (2); each benefit index is calculated based on a quantity representative of a torque delivered and / or on an electric current absorbed by the automotive starter generator (2) in the respective operating condition and is indicative of a benefit in terms of fuel saving obtainable in said operating condition in relation to a variation in the consumption of electrical energy absorbed by the automotive starter generator (2) in the respective operating condition with respect to a reference operating condition thereof;- determine a quota of the torque required to the automotive hybrid propulsion unit to be delivered by the automotive starter generator (2) based on the benefit indexes; and- control the automotive starter generator (2) to make it deliver the determined torque quota attributed to it.

2. The automotive control software according to claim 1, wherein the reference operating condition of the automotive starter generator (2) corresponds to a condition of nonoperation of the automotive starter generator (2).

3. The automotive control software according to claim 1 or 2, furthermore designed to cause, when executed, the automotive electronic processing resources (1) to become further configured to calculate the quota of the torque required to the automotive hybrid propulsion unit to be delivered by the automotive starter generator (2) also based on a charge status of an automotive electrical energy storage unit.

4. The automotive control software according to claim 3, furthermore designed to cause, when executed, the automotive electronic processing resources (1) to become further configured to calculate the quota of torque required to the automotive hybrid propulsion unit to be delivered by the automotive starter generator (2) in different possible operating conditions of the automotive starter generator (2) implementing the following operations:- determine values of a reference electric current representative of the electric absorption of the automotive starter generator (2) in the different possible operating conditions of the automotive starter generator (2), based on a calibration map (16) of the reference electric current containing different values of the reference electric current as a function of the benefit index and the electric charge status of the automotive electrical energy storage unit;- determine values of the energy losses in the different possible operating conditions of the automotive starter generator (2) based on a calibration map (17) of the energy losses containing different values of the energy losses as a function of the electric charge status of the automotive electrical energy storage unit and of the difference between the electric current absorbed by the automotive starter generator (2) and the reference electric current determined for the different possible operating conditions of the automotive starter generator (2); and- determine the quota of the torque required to the automotive hybrid propulsion unit to be delivered by the automotive starter generator (2) in the different possible operating conditions of the automotive starter generator (2) based on the values of the energy losses determined for the different possible operating conditions of the automotive starter generator (2).

5. The automotive control software according to claim 4, wherein the calibration map (16) of the reference electric current comprises:- a relatively low state-of-charge area (16A), in which the values of the reference electric current are relatively low,- a relatively high state-of-charge area (16C), in which the values of the reference electric current are relatively high; and, optionally,- an intermediate state-of-charge area (16B) with values between those of the relatively low state-of-charge area (16A) and the relatively high state-of-charge area (16C), in which the reference electric current values are intermediate between those ofthe relatively low state-of-charge area (16A) and the relatively high state-of-charge area (16C).

6. The automotive control software according to claim 5, wherein the area with intermediate state-of-charge values (16B) of the reference electric current calibration map (16) comprises:- a relatively low benefit-index sub-area (16BA), in which the values of the reference electric current are relatively low, in particular analogously to those of the area with relatively low state-of-charge (16A);- a relatively high benefit-index sub-area (16BC), in which the reference electric current values are relatively high, in particular equal to those of the area with relatively high state-of-charge (16C); and, optionally- an intermediate benefit-index sub-area (16BB) between those in the sub-areas with relatively low benefit index (16BA) and relatively high benefit index (16BC), in which the reference electric current values are intermediate between those in the sub-areas with relatively low benefit index (16BA) and relatively high benefit index (16BC), in particular they progressively increase as the benefit index values increase.

7. The automotive control software according to one of the claims from 4 to 6, wherein the calibration map (17) of the energy losses comprises:- an area with relatively high energy loss values (17A) for negative differences between the reference electric current determined for the given operating condition and the electric current absorbed by the automotive starter generator (2); and- an area with relatively low energy loss values (17B), in particular null values, for positive differences between the reference electric current determined for the given operating condition and the electric current absorbed by the automotive starter generator (2).

8. The automotive control software according to any one of the preceding claims and designed to cause, when executed, the automotive electronic processing resources (1), in order to determine the quota of the torque required to the automotive hybrid propulsion unit to be delivered by the automotive starter generator (2) in the different possible operating conditions of the automotive starter generator (2), to become further configured to select the quota of the torque to be delivered by the automotive starter generator (2)from the torques delivered by the automotive starter generator (2) based on which the benefit indexes have been calculated.

9. Automotive electronic processing resources (1) comprising the control software according to any one of the preceding claims.

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