Method and system for controlling a hybrid powertrain on the basis of torque gradients
Patent Information
- Application Number
- EP2023721414
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-04-27
- Filing Date
- 2023-04-24
- Publication Date
- 2025-03-05
AI Technical Summary
Hybrid powertrains experience oscillations and instability in the optimal operating point due to phase shifts between thermal and electric motor consumption models, leading to torque oscillations and self-sustained oscillating behavior in energy management.
A method and system for controlling hybrid powertrains that determine a raw torque setpoint for the thermal engine based on overall consumption, calculate an equivalence factor and its gradient, and filter torque gradients at the crankshaft to limit dynamic evolution, using configurable function tables and first-order filtering to stabilize the optimal torque.
The solution effectively reduces dynamic evolution of the optimal operating point, inhibiting oscillations and maintaining stability while adhering to optimization constraints, ensuring compliance with battery energy dynamics and torque requests.
Smart Images
Figure 1.1
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE: Method and system for controlling a hybrid powertrain based on torque gradients
[0003] Technical field
[0004] The technical field of the invention is the control of hybrid powertrains.
[0005] A hybrid vehicle is generally equipped with a combustion engine and one or more electric motors. Such a hybrid vehicle, like other motor vehicles, must be able to comply with the emission standards in each of the countries in which the vehicle is sold, and allow for a grain of performance as well as a gain in fuel consumption.
[0006] Hybrid motor vehicles can be equipped with different powertrains. In particular, so-called mild hybrid powertrains are known, in which the thermal engine is associated with an electric machine that can function as a motor or as a generator. The primary drive shaft is connected to the crankshaft of the thermal engine, for example by elastic means such as a belt. The primary drive shaft is associated with a gearbox so as to offer a plurality of possible transmission ratios between the rotational speed of the engine and the rotational speed of the primary drive shaft. The electric machine is then coupled to the thermal engine and its drive ratio with the wheels cannot vary independently of that of the thermal engine.
[0007] Powertrains are also known in which the gear ratios are independent for the engine and for the electric machine. For example, document FR-A1-3022495 discloses an arrangement with a heat engine and at least one first electric machine mounted at the end of the shaft.
[0008] Regardless of the hybridization of the vehicle's powertrain, it is necessary to have a control method for managing the distribution of the vehicle's driving power between the various traction components. In other words, the driver's torque request is distributed between the thermal engine and the electric machine(s), taking into account the respective transmission ratios and any constraints that may exist. These constraints include the following:
[0009] • Taking into account the “driver’s wishes” through the pressing of the accelerator pedal
[0010] • Pollution control
[0011] • Thermal comfort (heating of the passenger compartment)
[0012] • Noise and shock management NVH (acronym for “Noise vibration and hardness”)
[0013] This control method comprises a series of steps also subsequently called "Energy Management Law" operating in two phases, the first being the definition of the optimization field based on the constraints cited previously and the second being the energy optimization linked to the overall consumption of the powertrain.
[0014] The optimization scope consists of defining possible torque ranges for the heat engine and for the electric machine(s). The following examples illustrate the optimization scope for different constraints.
[0015] • For pollution control constraints, in the case of cold operation requiring rapid heating of a pollution control catalyst, a high torque window can be imposed on the thermal engine to increase thermal losses.
[0016] • For vibration constraints, it may be necessary to limit the gearbox ratios and limit the torque of the thermal engine to a predetermined range depending on the rotation speed.
[0017] • For passenger compartment heating constraints, the thermal engine can be required to achieve a minimum torque in order to obtain a rapid increase in the temperature of the coolant and consequently increase the passenger compartment heating temperature.
[0018] This field of optimization is generally not reduced to a single choice of torques for each driving source, the energy management law can then define the operating point / the optimal distribution of torque or power between the traction components to optimize the overall consumption of the powertrain according to the energy present in the battery and the torque demand at the driver's wheel.
[0019] The optimization field being generally open, depending on the type of optimization present in the energy management law, the optimal operating point can evolve very quickly depending on the physical parameters and the energy representations of the traction devices.
[0020] We take the example of a linear model of consumption of a thermal engine of type
[0021] Cons ENG (TENC > ) = A_ENG * T_ENG + B_ENG (Eq. l)
[0022] With :
[0023] A ENG and B ENG: coefficients dependent on the rotation speed of the thermal engine and
[0024] T ENG: the torque required at the output of the thermal engine.
[0025] We also take the example of a second-order polynomial model of consumption of an electric motor of type
[0026] With :
[0027] A ME and B_ME and C ME: coefficients dependent on the rotation speed of the electric motor and
[0028] T ME: the torque required at the output of the electric motor. It happens that, in certain cases of use, the rotation speeds of the electric machine and the thermal engine are not in phase, (for example, because of the clearances present in the gearbox, the flywheel, or the elasticity of the connecting belt between the engine crankshaft and the output shaft of the electric machine, etc.), and that certain physical mechanisms cause rotation speed oscillations, for example the management of the lift of variable height valves involving oscillations in the rotation speed of the thermal engine at certain operating points.
[0029] The phase shift of the electric (Eq. 2) and thermal (Eq. 1) models implies that at a given time t, the thermal engine has a lower consumption than that of the electric machine. This phase shift then induces the emission by the consumption optimization of a torque target of the thermal engine greater than that of the electric motor.
[0030] It then follows that at a later time t + t, due to the phase shift of the electric and thermal models, the electric motor has the lowest consumption. Consumption optimization then issues a torque target for the thermal engine that is lower than that of the electric motor.
[0031] The situations described at times t and t + s can follow one another and create torque oscillations. The phase shift between the consumption models of the thermal engine and the electric motors then tends to increase and maintain the oscillation of the optimal torque setpoints in an even more dynamic manner.
[0032] An instability of the operating point thus appears in certain situations due to a self-sustained oscillating behavior of the management law.
[0033] The technical problem to be solved is thus how to inhibit any oscillation and instability of the hybrid powertrain linked to the determination of the optimal operating point by the energy management law while respecting the optimization field and the normal evolution of this point. Presentation of the invention
[0034] The subject of the invention is a method for controlling a hybrid powertrain of a motor vehicle, comprising a heat engine and at least one electric machine associated with a battery, comprising the following steps: determining, by means of an energy management law, a raw torque setpoint of the heat engine as a function of the overall consumption of the powertrain, the consumption of the heat engine and of at least one electric machine, determining an equivalence factor as well as the gradient of the equivalence factor as a function of the current energy present in the battery and the energy target of the battery, determining the torque at the crankshaft as a function of the target torque required at the wheel and the gear ratio obtained from the energy management law and determining the gradient of the torque at the crankshaft,a minimum value of the thermal engine torque gradient and a maximum value of the thermal engine torque gradient are determined by means of configurable tables, each of which is a function of the gradient of the equivalence factor and the filtered target torque gradient at the crankshaft; the optimal torque of the thermal engine is determined as a function of the raw torque setpoint of the thermal engine by limiting its dynamic evolution as a function of the minimum value of the thermal engine torque gradient and the maximum value of the thermal engine torque gradient.
[0035] Control method according to claim 1, comprising a step of first-order filtering of the torque gradient at the crankshaft as a function of a stored time constant.
[0036] The method may comprise the following steps: determining that a first logical value takes a first value if a predefined minimum value of the optimal torque of the thermal engine is greater than the optimal torque value of the thermal engine, if this is not the case, the first logical value takes a second value, determining that a second logical value takes a first value if the predefined maximum value of the optimal torque of the thermal engine is less than the optimal torque value of the thermal engine, if this is not the case, the second logical value takes a second value, determining a selection value based on the logical OR operation between the first logical value and the second logical value, transmitting, to the determination of the optimal torque of the thermal engine,a first set comprising the minimum value of the thermal engine torque gradient and the maximum value of the thermal engine torque gradient as the minimum final thermal engine torque gradient and the maximum final thermal engine torque gradient if the selection value takes the first value and a second set of predefined values comprising a default minimum value of the thermal engine torque gradient and a default maximum value of the thermal engine torque gradient if the selection value takes the second value.,
[0037] The default minimum value of the thermal engine torque gradient can take a lower value than the minimum value of the thermal engine torque gradient and the default maximum value of the thermal engine torque gradient can take a higher value than the maximum value of the thermal engine torque gradient.
[0038] The invention also relates to a system for controlling a hybrid powertrain of a motor vehicle, comprising a first calculation means configured to execute an energy management law so as to determine a raw torque setpoint of the heat engine, the control system comprising: a second calculation means and a third calculation means configured to determine a gradient of an equivalence factor of the current energy present in the battery and of the battery energy target, a fourth calculation means and a fifth calculation means configured to determine a torque gradient at the crankshaft as a function of the target torque required at the wheel and of the gear ratio, a sixth calculation means and a seventh calculation means configured to respectively determine a maximum value and a minimum value of the heat engine torque gradient as a function of the gradient of the equivalence factor,of the torque gradient at the crankshaft and a table stored in the respective calculation means, and an eighth calculation means configured to determine an optimal torque setpoint as a function of the raw torque setpoint and the minimum and maximum values of the thermal engine torque gradient so that its dynamics are modified.,
[0039] The system may comprise a filtering means configured to perform first-order filtering of the gradient of the torque at the crankshaft transmitted to the sixth calculating means and to the seventh calculating means as a function of a stored time constant.
[0040] The system may comprise a first memory comprising a default minimum value of the thermal engine torque gradient and a default maximum value of the thermal engine torque gradient, a second memory comprising a minimum value of the optimal torque of the thermal engine and a maximum value of the optimal torque of the thermal engine, a first comparison means configured to emit a first value if the current value of the optimal torque of the thermal engine is greater than the minimum value of the optimal torque of the thermal engine, and to emit a second value if this is not the case, a second comparison means configured to emit a first value if the current value of the optimal torque of the thermal engine is less than the maximum value of the optimal torque of the thermal engine and to emit a second value if this is not the case,a Boolean operator configured to apply a truth table OR to the values received from the first comparison means and the second comparison means, the switch being configured to transmit to the eighth calculation means the minimum value of the thermal engine torque gradient and the maximum value of the thermal engine torque gradient if a second value is received from the Boolean operator and to transmit the default minimum value of the thermal engine torque gradient and the default maximum value of the thermal engine torque gradient if a first value is received from the Boolean operator.,
[0041] Brief description of the drawings
[0042] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:
[0043] - figure 1 illustrates the main steps of a control method according to the invention, and
[0044] - Figure 2 illustrates the main elements of a control system according to the invention.
[0045] Detailed description
[0046] The method for controlling a hybrid powertrain of a motor vehicle aims to control and reduce the dynamics of evolution of the optimal operating point of the energy management law while guaranteeing compliance with the optimization field at all times and the dynamics expected in the conditions of battery energy and power / torque request at the current wheel. The hybrid powertrain comprises a thermal engine and at least one electric motor associated with a battery.
[0047] The following variables are defined:
[0048] - WHL TQ TG: target torque required at the wheel, developed from the driver's request and third-party functions having an impact on its development (Cruise control, autonomous driving, etc.) - ENG TQ OPT MIN: minimum value of the optimal torque of the thermal engine emanating from the upstream functions of the energy management law which deals with the arbitration of constraints linked to approval, thermal comfort, battery management, etc.
[0049] - ENG TQ OPT MAX: maximum value of the optimal torque of the thermal engine emanating from the upstream functions of the energy management law which deals with the arbitration of constraints linked to approval, thermal comfort, battery management, etc.
[0050] - ENG TQ OPT RAW: raw torque setpoint of the thermal engine resulting from the energy management law, torque for which we seek to reduce the dynamics of evolution
[0051] - FAC EQ: electrical consumption equivalence factor based on the equivalent consumption minimization method;
[0052] - ENG TQ OPT: the optimal torque of the thermal engine, then transmitted to the function of realizing the torque instructions of the powertrain.
[0053] - EGY CRT: the current energy present in the battery, information transmitted directly by the function managing the battery control.
[0054] - EGY TGT: the target energy of the battery, calculated internally by the energy management according to a configured nominal target and according to specific energy needs (Activation of a charging mode via a driver interface, increase in energy to carry out a particular pollution control function, etc.).
[0055] The equivalence factor FAC EQ is used to determine the overall consumption of the powertrain ENC ,T EM) depending on the consumption of the thermal engine G ) and the consumption of the electrical machine(s) expressed as follows:
[0056] C° ns global(T ENC ,T EM ) = ° nS ENG(T ENG ) + C° ns EM (T EM ) * FAC_EQ (Eq. 3)
[0057] In other words, the FAC EQ value represents the equivalence factor between the consumption of at least one electric motor and the thermal engine, this parameter being dynamic and mainly a function of the energy level present in the battery. This factor is greater than 1.
[0058] The equivalence factor FAC EQ is usually constructed from the current energy present in the battery and the energy target. To determine the value of the equivalence factor FAC EQ, a proportional gain (EGY F AC GAIN) is applied to the difference between the current energy present in the battery and the energy target, then a neutral value is added (EGY FAC NEUTRAL), a value implying that the electrical energy is worth as much as the thermal energy.
[0059] The proportional gain value as well as the neutral value are usually set iteratively.
[0060] Several rolling cycles are carried out with several fixed equivalence factor values and allow:
[0061] - to find a neutral value, a value which means that the electrical energy, although changing during the cycle, is the same at the beginning of the cycle as at the end of the cycle.
[0062] - to find the values for which we know how to estimate the gain or consumption of electrical energy per kilometer as a function of the energy at the start of the cycle, at the end of the cycle and the distance traveled.
[0063] The proportional gain is thus set in order to obtain the desired charge / discharge according to the desired dynamics which is generally a compromise between services (availability of electric mode, unlimited use of battery energy to optimize consumption, NVH implied by a high level of recharge to get closer to the target, etc.)
[0064] Figure 1 illustrates the main steps of the control method according to the invention.
[0065] During a first step 1, the operating point of the hybrid powertrain is determined by means of an energy management law, i.e., a raw torque setpoint of the thermal engine ENG TQ OPT RAW as a function of the overall consumption of the powertrain, via the analytical resolution of the equation making it possible to define the operating point involving the lowest possible consumption.
[0066] In a second step 2, the equivalence factor FAC EQ is determined based on the current energy present in the battery and the battery energy target.
[0067] FAC_EQ=(EGY_TGT-EGY_CRT)*EGY_FAC_GAIN +
[0068] EGY FAC NEUT
[0069] With
[0070] EGY FAC GAIN, a parameterized proportional gain
[0071] EGY FAC NEUT, a neutral equivalence factor value
[0072] We then quantify the variation of the FAC EQ equivalence factor over a predefined period (for example one second). To do this, we subtract the current value of the FAC EQ equivalence factor from its value at the previous time step and divide the result by this same time step. We then obtain a gradient of the FAC EQ equivalence factor GRD allowing us to know the evolution of the FAC EQ equivalence factor over the predefined period.
[0073] In a third step 3, the target torque required at the wheel WHL TQ TG and the gear ratio ENG RAT from the energy management laws are obtained. The torque variation at the crankshaft and therefore at the heat engine is then quantified. To do this, the target torque required at the wheel WHL TQ TG is divided by the gear ratio ENG RAT between the heat engine and the wheel. The torque at the crankshaft CRK TQ TG is obtained. The torque gradient at the crankshaft CRK TQ TG is determined in a similar way to the determination of the gradient of the equivalence factor FAC EQ GRD. More precisely, we subtract the current value of the torque at the crankshaft CRK TQ TG from its value at the previous time step and divide the result by this same time step. We then obtain the gradient of the torque at the crankshaft CRK TQ TG GRD characterizing the evolution of the target torque setpoint at the wheel at the crankshaft over the predetermined duration.
[0074] Since the torque gradient at the crankshaft CRK TQ TG GRD can be noisy due to the evolution of the target torque required at the wheel WHL TQ TG, a first-order filter is introduced with an adjustable time constant TAU in order to obtain a filtered target torque gradient at the crankshaft CRK TQ TG GRD FIL.
[0075] During a fourth step 4, a minimum value of the thermal engine torque gradient CRK TQ OPT GRD MIN TABLE and a maximum value of the thermal engine torque gradient CRK TQ OPT GRD MAX TABLE are determined by means of a two-dimensional configurable table, respectively TABLE_2D_GRD_POS_MIN and
[0076] TABLE_2D_GRD_POS_MAX each function of the gradient of the equivalence factor FAC EQ GRD and the filtered target torque gradient at the crankshaft CRK TQ TG GRD FIL.
[0077] The minimum value of the thermal engine torque gradient CRK TQ OPT GRD MIN TABLE and the maximum value of the thermal engine torque gradient CRK TQ OPT GRD MAX TABLE are representative of the normal evolution of the optimal torque of the thermal engine. The term "normal evolution of the optimal torque of the thermal engine" refers to the increase in torque or the decrease in torque that can naturally be observed during an evolution of the filtered value of the torque gradient at the crankshaft CRK TQ TG GRD FIL and the equivalence factor gradient FAC EQ GRD. The filtered value of the torque gradient at the crankshaft CRK TQ TG GRD FIL corresponds to the target torque setpoint required at the wheel WHL TQ TG, and therefore to the driver's wishes:
[0078] - If the driver's will brought back to the crankshaft increases by a value X (in Nm / s), we expect the optimal torque of the thermal engine to increase by a value Y (in Nm / s) slightly higher than the value X, and parameterized in the first table TABLE_2D_GRD_POS_MAX.
[0079] - If the equivalence factor increases, then the optimal torque of the thermal engine is expected to increase by an amount of torque value Z (in Nm / s) parameterized in the first TABLE_2D_GRD_POS_MAX.
[0080] In a fifth step 5, it is determined whether the minimum value of the optimal torque of the thermal engine ENG TQ OPT MIN is greater than the optimal torque value of the thermal engine ENG TQ OPT. If this is the case, it is determined that a first logical value is equal to a first value. If this is not the case, it is determined that the first logical value is equal to a second value.
[0081] It is also determined whether the maximum value of the optimal torque of the thermal engine ENG TQ OPT MAX is less than the optimal torque value of the thermal engine ENG TQ OPT. If this is the case, it is determined that a second logical value is equal to a first value. If this is not the case, it is determined that the second logical value is equal to a second value.
[0082] In a sixth step 6, a selection value is determined based on the logical OR operation between the first logical value and the second logical value. In other words, the selection value takes a first value if at least one of the first logical value and the second logical value is equal to the first value. If this is not the case, the selection value takes a second value.
[0083] During a seventh step 7, the minimum final thermal engine torque gradient CRK TQ OPT GRD MIN and the maximum final thermal engine torque gradient CRK TQ OPT GRD MAX are chosen, subsequently used to control and reduce the dynamics of the evolution of the optimal torque of the thermal engine from a first set of values comprising the minimum value of the thermal engine torque gradient CRK TQ OPT GRD MIN TABLE and the maximum value of the thermal engine torque gradient CRK TQ OPT GRD MAX TABLE and a second set of values comprising a minimum default value of the thermal engine torque gradient CRK TQ OPT GRD MIN DFT and a maximum default value of the thermal engine torque gradient CRK TQ OPT GRD MAX DFT depending on the selection value.
[0084] More precisely, the first set of values is chosen if the selection value takes the second value, and the second set of values is chosen if the selection value takes the first value.
[0085] This choice of gradient allows, in the case where the optimal torque value of the thermal engine ENG TQ OPT, whose dynamics have been reduced, to be outside the optimization field defined by the rapid evolution of the minimum value of the optimal torque of the minimum thermal engine ENG TQ OPT MIN and the maximum value of the optimal torque of the thermal engine ENG TQ OPT MAX, to choose default gradients CRK TQ OPT GRD MIN DFT and CRK TQ OPT GRD MAX DFT allowing to quickly or even instantly put the optimal torque of the thermal engine ENG TQ OPT back into its optimization field.
[0086] The default gradients CRK TQ OPT GRD MIN DFT and CRK TQ OPT GRD MAX DFT are generally lower / higher in value than the nominal gradients from the two-dimensional tables.
[0087] The limits being a function of various constraints (pollution control, passenger compartment thermal comfort, etc.), it happens that one of the limits changes very quickly or even instantly when a function is activated (for example: significantly higher passenger compartment heating request): if the optimal torque of the thermal engine ENG TQ OPT is located at the level of the minimum value of the optimal torque of the thermal engine ENG TQ OPT MIN and the latter increases sharply and quickly to ensure a torque for passenger compartment thermal comfort which requires heating the thermal engine quickly by imposing a high minimum torque on it, then it is imperative to allow the optimal torque of the thermal engine ENG TQ OPT to respect this new minimum limit: the optimal torque of the thermal engine ENG TQ OPT is at the time of the increase below the new minimum value of the optimal torque of the thermal engine ENG TQ OPT MIN,the gradients chosen by default then allow a rapid or even instantaneous evolution of the optimal torque of the thermal engine ENG TQ OPT towards the minimum value of the optimal torque of the thermal engine ENG TQ OPT MIN although the driver's will or the equivalence factor has not changed.
[0088] During an eighth step 8, the optimal torque of the thermal engine ENG TQ OPT is determined as a function of the raw torque setpoint of the thermal engine ENG TQ OPT RAW resulting from the energy management law by limiting its dynamic evolution as a function of the minimum final gradient of thermal engine torque CRK TQ OPT GRD MIN and the maximum final gradient of thermal engine torque CRK TQ OPT GRD MAX via the following logic: ENG_TQ_OPT(t)
[0089] = Max(Min(ENG_TQ_OPT_RAW(t); ENG_TQ_OPT(t - dt) + CRK_TQ_OPT_GRD_MAX * dt); ENG_TQ_OPT(t - dt) + CRK_TQ_OPT_GRD_MIN * dt)
[0090] With t the current calculation step and dt the duration between two consecutive calculation steps of the strategy.
[0091] This determination thus makes it possible to obtain the optimal thermal engine torque ENG TQ OPT, the dynamics of which are potentially lower than the raw torque setpoint of the thermal engine ENG TQ OPT RAW.
[0092] The dynamics of the optimal thermal engine torque, and the dynamics of the optimal operating point resulting from the Energy Management Law, are then controlled and reduced while maintaining the dynamics normally expected according to the parameters having a direct impact on its choice (Wheel torque and equivalence factor) while guaranteeing compliance with the optimization field at all times. The control process thus makes it possible to cancel the self-oscillation phenomenon while controlling the dynamics of the operating point.
[0093] The invention also relates to a control system for a hybrid powertrain of a motor vehicle, illustrated in Figure 2.
[0094] The control system 10 comprises a first calculation means 11 configured to execute an energy management law so as to determine the operating point of the hybrid powertrain, i.e., a raw torque setpoint of the thermal engine ENG TQ OPT RAW as a function of the overall consumption of the powertrain, via the analytical resolution of the equation making it possible to define the operating point involving the lowest possible consumption.
[0095] A second calculation means 12 is configured to determine the equivalence factor FAC EQ as a function of the current energy present in the battery and the energy target of the battery.
[0096] A third calculation means 13 determines the gradient of the equivalence factor FAC EQ GRD as a function of the equivalence factor FAC EQ at the current instant, of a stored value of the equivalence factor FAC EQ at a previous instant, and of the duration between the current instant and the previous instant. On the first occurrence, the gradient is initialized to its current value.
[0097] A fourth calculation means 14 determines the torque at the crankshaft CRK TQ TG as a function of the target torque required at the wheel WHL TQ TG and the gear ratio ENG RAT.
[0098] A fifth calculation means 15 determines the gradient of the torque at the crankshaft CRK TQ TG GRD as a function of the torque at the crankshaft CRK TQ TG at the current instant, of a stored value of the torque at the crankshaft CRK TQ TG at a previous instant, and of the duration between the current instant and the previous instant. On the first occurrence, the gradient is initialized to a predefined default value. A filtering means 16 performs first-order filtering of the gradient of the torque at the crankshaft CRK TQ TG GRD as a function of a time constant TAU.
[0099] A sixth calculation means 17 associated with a memory comprising a first table TABLE_2D_GRD_PO S_MAX is configured to determine a maximum value of the thermal engine torque gradient CRK TQ OPT GRD MAX TABLE as a function of the gradient of the equivalence factor FAC EQ GRD and the gradient of the torque at the crankshaft CRK TQ TG GRD FIL.
[0100] A seventh calculation means 18 associated with a memory comprising a table TABLE_2D_GRD_POS_MIN is configured to determine a minimum value of the thermal engine torque gradient CRK TQ OPT GRD MIN TABLE as a function of the gradient of the equivalence factor FAC EQ GRD and the gradient of the torque at the crankshaft CRK TQ TG GRD FIL.
[0101] A first memory 19 includes a default minimum value of the thermal engine torque gradient CRK TQ OPT GRD MIN DFT and a default maximum value of the thermal engine torque gradient CRK TQ OPT GRD MAX DFT.
[0102] A second memory 20 includes a minimum value of the optimal torque of the thermal engine ENG TQ OPT MIN and a maximum value of the optimal torque of the thermal engine ENG TQ OPT MAX.
[0103] A first comparison means 21 is configured to determine whether the current value of the optimal torque of the thermal engine ENG TQ OPT is greater than the minimum value of the optimal torque of the thermal engine ENG TQ OPT MIN and to emit a first value if this is the case, or a second value if this is not the case.
[0104] A second comparison means 22 is configured to determine whether the current value of the optimal torque of the thermal engine ENG TQ OPT is less than the maximum value of the optimal torque of the thermal engine ENG TQ OPT MAX and to emit a first value if this is the case, or a second value if this is not the case. A Boolean operator 23 is configured to apply a truth table OR to the signals received from the first comparison means 20 and the second comparison means 21.
[0105] A switch 24 allows the minimum value of the thermal engine torque gradient to be chosen.
[0106] CRK TQ OPT GRD MIN TABLE and the maximum value of the thermal engine torque gradient CRK TQ OPT GRD MAX TABLE if a second value is received from the Boolean operator 23 and to choose the default minimum value of the thermal engine torque gradient CRK TQ OPT GRD MIN DFT and the default maximum value of the thermal engine torque gradient CRK TQ OPT GRD MAX DFT if a first value is received from the Boolean operator 23.
[0107] An eighth calculation means 25 is configured to determine the optimal torque setpoint ENG TQ OPT as a function of the raw torque setpoint ENG TQ OPT RAW and the values received from the switch 24 via the following logic:
[0108] ENG_TQ_OPT(t)
[0109] = Max(Mm(ENG_TQ_OPT_RAW(t); ENG_TQ_OPT(t - dt) + CRK_TQ_OPT_GRD_MAX * dt); ENG_TQ_OPT(t - dt) + CRK_TQ_OPT_GRD_MIN * dt)
[0110] With t the current calculation step and dt the duration between two consecutive calculations of the strategy.
[0111] It will be understood that the different memories can also be distinct memory spaces included in the same physical memory.
Claims
DEMANDS 1. A method for controlling a hybrid powertrain of a motor vehicle, comprising a heat engine and at least one electric machine associated with a battery, comprising the following steps: an optimal gross torque setpoint of the heat engine is determined by means of an energy management law as a function of the overall consumption of the powertrain, the consumption of the heat engine and at least one electric machine; an equivalence factor and the gradient of the equivalence factor are determined as a function of the current energy present in the battery and the target energy of the battery; the torque at the crankshaft is determined as a function of the target torque required at the wheel and the gear ratio obtained from the energy management law; and the torque gradient at the crankshaft is determined.A minimum value and a maximum value of the internal combustion engine torque gradient are determined using parametric tables, each based on the gradient of the equivalence factor and the target torque gradient filtered at the crankshaft. The optimal torque of the internal combustion engine is determined as a function of the raw torque setpoint of the internal combustion engine by limiting its dynamic evolution according to the minimum value of the internal combustion engine torque gradient and the maximum value of the internal combustion engine torque gradient.
2. Control method according to claim 1, comprising a first-order filtering step of the torque gradient at the crankshaft as a function of a stored time constant.
3. A control method according to any one of claims 1 or 2, comprising the following steps: A first logical value is determined to take a first value if a predefined minimum value of the optimal torque of the heat engine is greater than the optimal torque value of the heat engine; if this is not the case, the first logical value takes a second value. A second logical value is determined to take a first value if the predefined maximum value of the optimal torque of the heat engine is less than the optimal torque value of the heat engine; if this is not the case, the second logical value takes a second value. A selection value is determined based on the OR logical operation between the first logical value and the second logical value. This value is then passed on to the determination of the optimal torque of the heat engine.a first set comprising the minimum value of the internal combustion engine torque gradient and the maximum value of the internal combustion engine torque gradient as the final minimum and maximum final internal combustion engine torque gradients if the selection value takes the second value, and a second set of predefined values comprising a default minimum value of the internal combustion engine torque gradient and a default maximum value of the internal combustion engine torque gradient if the selection value takes the first value.
4. Control method according to any one of claims 1 to 3, in which the minimum default value of the thermal engine torque gradient has a value lower than the minimum value of the thermal engine torque gradient and the maximum default value of the thermal engine torque gradient has a value higher than the maximum value of the thermal engine torque gradient.
5. Control system for a hybrid powertrain of a motor vehicle, comprising a first computing means (11) configured to execute an energy management law so as to to determine a raw torque setpoint for the internal combustion engine, the control system being characterized in that it comprises: a second calculation means (12) and a third calculation means (13) configured to determine a gradient of an equivalence factor as a function of the powertrain consumptions, a fourth calculation means (14) a fifth calculation means (15) configured to determine a torque gradient at the crankshaft as a function of the target torque required at the wheel and the gear ratio, a sixth calculation means (17) and a seventh calculation means (18) configured to determine respectively a maximum value and a minimum value of the internal combustion engine torque gradient as a function of the gradient of the equivalence factor, the torque gradient at the crankshaft and a table stored in the respective calculation means,and an eighth calculation method (25) configured to determine an optimal torque setpoint as a function of the raw torque setpoint and the minimum and maximum values of the internal combustion engine torque gradient so that its dynamics are modified.
6. Control system according to claim 5, comprising a filtering means (16) configured to perform first-order filtering of the torque gradient at the crankshaft transmitted to the sixth calculation means (17) and the seventh calculation means (18) as a function of a stored time constant.
7. A control system according to any one of claims 5 or 6, comprising a first memory (19) comprising a default minimum value of the internal combustion engine torque gradient and a default maximum value of the internal combustion engine torque gradient, a second memory (20) comprising a minimum value of the optimal internal combustion engine torque and a maximum value of the optimal internal combustion engine torque, and a first comparison means (21) configured to output a first value if the current value of the optimal internal combustion engine torque is greater than the minimum value of the optimal torque of the internal combustion engine, and to issue a second value if this is not the case, a second comparison means (22) configured to issue a first value if the current value of the optimal torque of the internal combustion engine is less than the maximum value of the optimal torque of the internal combustion engine and to issue a second value if this is not the case, a Boolean operator (23) configured to apply an OR truth table to the values received from the first comparison means (20) and the second comparison means (21),the switch (24) being configured to transmit to the eighth calculation means (24) the minimum value of the internal combustion engine torque gradient and the maximum value of the internal combustion engine torque gradient if a second value is received from the Boolean operator (22) and to transmit the default minimum value of the internal combustion engine torque gradient and the default maximum value of the internal combustion engine torque gradient if a first value is received from the Boolean operator (22).