WO2021058146A1

WO2021058146A1 - Method for selecting the target state of a vehicle drive train

Info

Publication number: WO2021058146A1
Application number: PCT/EP2020/066519
Authority: WO
Inventors: Aurelien Lefevre
Original assignee: Renault S.A.S; Nissan Motor Co., Ltd.
Priority date: 2019-09-26
Filing date: 2020-06-15
Publication date: 2021-04-01
Also published as: CN114502438A; JP2022550264A; FR3101305B1; KR20220063186A; FR3101305A1; EP4034437A1

Abstract

Disclosed is a method for selecting the target state of a vehicle drive train connecting a plurality of traction members, including a heat engine and at least one electric machine, to the wheels of the vehicle by means of a transmission, among a set of states present in the transmission and defined by different combinations of couplers and reducers so as to ensure the transfer of the torque from the heat engine and/or the electric machine to the wheels through one or more gear ratios, characterised in that the selection of the target state includes a step of determining the minimum and maximum speeds of travel of the vehicle (DLS_MIN_RELIA_VH_SPD) and (DLS_MAX_RELIA_VH_SPD) enabling the mechanical reliability of the traction members to be guaranteed in each of the available states of the drive train.

Description

DESCRIPTION

Title of the invention: METHOD OF SELECTING THE STATUS SETPOINT OF A VEHICLE DRIVE CHAIN The present invention relates to the control of hybrid powertrains.

More precisely, it relates to a method for selecting the state setpoint of a vehicle kinematic chain connecting several traction units including a heat engine and at least one electric machine to the wheels of the vehicle by means of a transmission, among a set of states present in the transmission defined by different combinations of couplers and reducers thereof to ensure the transfer of torque from the heat engine and / or the electric machine towards the wheels on one or more ratios reduction.

The mechanical limits of a GMP are linked to the gear ratios of its transmission, to the speed limits of the traction units, and to its operating characteristics. These limits must be determined consistently, so as to provide state selection strategies with the information they need in good time.

A hybrid vehicle generally comprises a set of traction units, including at least one heat engine and one electric machine, making up its powertrain, or GMP. The GMP of a hybrid vehicle has multiple operating limits, which are imposed by the minimum / maximum rotation speeds of the rotating parts, and in particular of its traction units: beyond these speeds, the traction units are in a situation of under-speed, or over-speed, with high risks of mechanical breakage.

To eliminate such risks on a thermal vehicle, it suffices to introduce into the gear changing strategies, the minimum and maximum speed values of the thermal engine, parallel to the value of the current speed. This information becomes insufficient in the case of a hybrid vehicle, in due to the diversity of the traction units and the operating modes of the GMP.

The states of a hybrid vehicle kinematic chain can be defined as combinations of coupler (s) and reducer (s) which are specific to the architecture of the vehicle, and of its GMP. The state selection strategies must take into account the mechanical limits of all the traction members. These strategies must anticipate changes of state, in particular to avoid under-revs or over-revs due to the dynamics of the vehicle and the reaction time of the GMP to carry out the changes of state. For the same purpose, they sometimes need to temporarily freeze certain status instructions.

From the publication FR 3023526, a method is known for developing a target kinematic chain state, through various arbitrations allowing the successive elimination of states that are not appropriate to the situation encountered. One of the trade-offs implemented concerns compliance with the reliability limits of the traction units, with regard to speed. However, the way in which this information is calculated is not specified in the document.

From the publication FR 3013019, another method is known for avoiding overspeeding of the traction units, thanks to the calculation of anticipated speeds, which are compared with speed limits guaranteeing the reliability of the GMP. However, it is also not specified how this information is calculated.

The present invention aims to ensure the mechanical reliability of a GMP, taking into account the particularity of the stresses imposed by its transmission and traction members.

For this purpose, the selection of the state setpoint includes a step of determining the minimum and maximum travel speeds of the vehicle making it possible to guarantee the mechanical reliability of the traction units on each of the available states of the kinematic chain.

Preferably, raw values of speeds of displacement, depending on:

- maximum travel speeds authorized by an electric machine, and

- minimum and maximum travel speeds authorized by the heat engine.

The present invention will be better understood on reading the following description of a non-limiting embodiment thereof, with reference to the appended drawing. [Fig.l] is a flowchart 1 of the proposed method.

This method makes it possible to provide transverse information in real time to a GMP computer responsible for selecting the states targeted by a hybrid vehicle GMP. This GMP can be provided, like that of publication EP 2694309 (to which reference may be made), with a heat engine and a single electric drive machine and comprising two concentric primary shafts each carrying at least one descent pinion on a secondary shaft connected to the wheels of the vehicle. The architecture described in this publication offers a nonlimiting application for the method which is the subject of the present invention.

The transverse information supplied to the computer are the minimum and maximum vehicle travel speeds, achievable in order to comply with the reliability constraints linked to the speeds of rotation of the traction units, on each of the kinematic chain states available.

This information is used to select the state setpoint of the kinematic chain connecting several traction units including a heat engine and at least one electric machine to the wheels of the vehicle via a transmission. The selection is made among a set of states present in the transmission, which are defined by different combinations of couplers and reducers, to ensure the transfer of torque from the heat engine and / or the electric machine towards the wheels, on one or more gear ratios. In Figure 1, we have indicated all the input data, which are necessary to develop the cross-sectional information:

- MAX_EM_SPD is the maximum speed attainable by the main traction machine, if it is present on the powertrain; this data is updated in real time by the function responsible for actuating the electric machine; ICE_TEMP is the water temperature of the heat engine, updated in real time; MAX_ICE_SPD is the maximum speed attainable by the heat engine; if an electric machine is coupled to the heat engine, MAX_ICE_SPD takes into account the maximum authorized speed of the latter; MAX_ICE_SPD is updated in real time by the function responsible for actuating the heat engine;

- DLS_TGT is the current state target of the kinematic chain;

- DLS_TYP_LIST is the vector of the energy types of states (thermal, electric or hybrid); this vector makes it possible to know what types of states are available on the powertrain and what their energy definitions are; DLS_TYP_LIST is provided by a third party function, which is specific to each GMP, and which does not vary during its operation;

- PAR_LIMIT_ENA is an adjustment parameter, which takes the value 1, or 0. PAR_LIMIT_ENA takes the value 1 when the GMP includes only one electric traction machine whose maximum speed limit must be taken, and this limit does not cannot be included in the value of the maximum speed of the heat engine MAX_ICE_SPD, because the electric machine is not directly mechanically connected to the heat engine; this is the case in the architecture described in the publication EP

2 694309, where it is possible to decouple the electric machine, and to have different gear ratios on the heat engine and on the latter; PAR_LIMIT_ENA takes the value 0 in the other cases, in particular when there is a second electric machine coupled directly to the heat engine.

The selection of the target state (or state setpoint) includes a step of determining the minimum and maximum speeds of movement of the vehicle DLS_MIN_RELIA_VH_SPD and DLS_MAX_RELIA_VH_SPD making it possible to guarantee the mechanical reliability of the traction units on each of the available states of the chain cinematic.

The types of states of the DLS_TYP_LIST vector can be the following:

- HEV_SER: series hybrid type traction;

- HEV_SER_RVR: series hybrid type traction with reversal of direction of the electric machine;

- HEV_PAR: parallel hybrid type traction;

- HEV_SER_PAR: hybrid type parallel series traction;

- TH: thermal type traction;

- EV: electric type traction;

- EV_RVR: electric type traction with direction reversal of the electric machine;

- NEUTRAL: no traction (no traction unit connected to the wheels);

- ABSENT: driveline state not defined on the vehicle: The output information is intended for the vehicle's calculation units responsible for selecting the driveline states. This information is preferably in vector form. The vectors DLS_MIN_RELIA_VH_SPD and DLS_MAX_RELIA_VH_SPD, represent the minimum and maximum speeds of movement of the vehicle, which make it possible to guarantee the mechanical reliability of the traction units on each of the states of the kinematic chain.

In the process flow, the raw values of the traversing speeds DLS_MIN_RELIA_VH_SPD_RAW and DLS_MAX_RELIA_VH_SPD_RAW are determined based on:

- maximum authorized displacement speeds DLS_MAX_EM_VH_SPD by an electric machine,

- minimum and maximum travel speeds DLS_MIN_ICE_VH_SPD and DLS_MAX_ICE_VH_SPD authorized by the heat engine.

The function Fl works out the vector of the maximum displacement speeds DLS_MAX_EM_VH_SPD authorized on each of the states of the kinematic chain, as a function of the maximum possible speed on the electric machine MAX_EM_SPD, of the wheel radius WHEEL_RAD and of the vector of the DLS_EM_RATIO gear ratios between the machine electric and the wheel on each state. The WHEEL_RAD and DLS_EM_RATIO parameters are vehicle specific. The maximum travel speed authorized by the electric machine is calculated in km / h as follows: DLS_MAX_EM_VH_SPD =

(MAX_EM_SPD) * (DLS_EM_RAT10) * (WHEEL_RAD) * (3.6) * (P / 30).

The raw values of the minimum and maximum vehicle travel speeds DLS_MIN_RELIA_VH_SPD_RAW and DLS_MAX_RELIA_VH_SPD_RAW are determined on each available state, depending on the traction energy type DLS_TYP_LIST (X) of that state.

The F2 function works out the vector of minimum and maximum movement speeds authorized on each state according to the DLS_MIN_ICE_VH_SPD and DLS_MAX_ICE_VH_SPD, according to the minimum and maximum speed possible on the thermal engine MIN_ICE_SPD, MAX_ICE_SPD, according to the wheel radius WHEEL_RAD, and as a function of the DLS_ICE_RATIO gear ratio between the heat engine and the wheel.

The MIN_ICE_SPD parameter represents the minimum rotation speed authorized on the heat engine. MIN_ICE_SPD is a function of the water temperature of the ICE_TEMP thermal engine.

Its value can be given by a configurable table, having as input data ICE_TEMP. It can also be provided directly by the function responsible for actuating the heat engine in the GMP control system. The WHEEL_RAD and DLS_ICE_RATIO parameters are vehicle specific. These speeds are calculated in km / h, as follows:

- DLS_MAX_ICE_VH_SPD = (MAX_ICE_SPD) * (DLS_ICE_RATIO) * (WHEEL_RAD) * (3.6) * (P / 30), and

- DLS_MIN_ICE_VH_SPD

= (MIN_ICE_SPD) * (DLS_ICE_RATIO) * (WHEEL_RAD) * (3.6) * (P / 30).

The F3 function develops vectors grouping the minimum vehicle speed limits DLS_MIN_RELIA_VH_SPD_RAW and maximum DLS_MAX_RELIA_VH_SPD_RAW attainable on each of the states of the kinematic chain, according to the energy type of each state. The states of the vector DLS_TYP_LIST include at least a neutral state, an electrical state, and a thermal state. These values are defined, according to the energy type X of the state concerned, having the value DLS_TYP_LIST (X), in the vector DLS_TYP_LIST:

- ABSENT state (not defined on the vehicle): DLS_MIN_RELIA_VH_SPD_RAW (X) = 0 km / h and DLS_MAX_RELIA_VH_SPD_RAW (X) = 0 km / h;

- NEUTRAL state (neutral): DLS_MIN_RELIA_VH_SPD_RAW (X) = 0 km / h, and DLS_MAX_RELIA_VH_SPD_RAW (X) does not meet a real limit, and can take very high values;

- TH state: (thermal): DLS_MIN_RELIA_VH_SPD_RAW (X) =

DLS_MIN_ICE_VH_SPD (X) and DLS_MAX_RELIA_VH_SPD_RAW (X) = DLS_MAX_ICE_VH_SPD (X);

- EV (electrical) or EV_RVR (electrical with direction reversal) state: DLS_MIN_RELIA_VH_SPD_RAW (X) = 0 km / h and DLS_MAX_RELIA_VH_SPD_RAW (X) = DLS_MAX_EM_VH_SPD (X);

- HEV_SER state (series hybrid traction) or HEV_SER_RVR: (reverse series hybrid traction): DLS_MIN_RELIA_VH_SPD_RAW (X)

= 0 km / h, and DLS_MAX_RELIA_VH_SPD_RAW (X) =

DLS_MAX_EM_VH_SPD (X);

- HEV_SER_PAR state (parallel hybrid):

DLS_MIN_RELIA_VH_SPD_RAW (X) = DLS_MIN_ICE_VH_SPD (X), and DLS_MAX_RELIA_VH_SPD_RAW (X) = the minimum value between DLS_MAX_ICE_VH_SPD (X) and DLS_MAX_EM_VH_SPD (X);

- HEV_PAR state (parallel hybrid): DLS_MIN_RELIA_VH_SPD_RAW (X) = DLS_MIN_ICE_VH_SPD (X).

The PAR_LIMIT_ENA adjustment parameter can take the value 1 or 0. It is equal to 1, when the GMP has only one electric machine, the maximum speed limit of which is not included in the value of the maximum speed of the heat engine MAX_ICE_SPD. In this case, DLS_MAX_RELIA_VH_SPD_RAW (X) is equal to the minimum value between DLS_MAX_ICE_VH_SPD (X) and DLS_MAX_EM_VH_SPD (X).

PAR_LIMIT_ENA takes the value 0 in the other cases. If PAR_LIMIT_ENA = 0, then DLS_MAX_RELIA_VH_SPD_RAW (X) is equal to DLS_MAX_ICE_VH_SPD (X).

In other words, when the GMP has only one electric machine, the maximum speed limit of which MAX_EM_SPD is not included in the value of the maximum speed of the heat engine (MAX_ICE_SP), the gross maximum speed of the vehicle is DLS_MAX_RELIA_VH_SPD_RAW (X) is the minimum value between the maximum speeds DLS_MAX_ICE_VH_SPD (X) and DLS_MAX_EM_VH_SPD (X) authorized by the heat engine and by the electric machine. In the other provisions of the GMP, the maximum gross speed of the vehicle DLS_MAX_RELIA_VH_SPD_RAW (X), is equal to the maximum speed authorized by the thermal engine DLS_MAX_ICE_VH_SPD (X).

Finally, the function F4, consolidates the vectors

DLS_MIN_RELIA_VH_SPD_RAW and DLS_MAX_RELIA_VH_SPD_RAW of vehicle travel limit speeds, on each of the kinematic chain states.

The first consolidation consists in subtracting or adding a vehicle speed difference SPD_OES to the set of reliability limits calculated for each of the different states of the current target DLS_TGT. The minimum and maximum gross vehicle travel speeds DLS_MIN_RELIA_VH_SPD_RAW and DLS_MAX_RELIA_VH_SPD_RAW are consolidated respectively by adding or subtracting a speed difference SPD_OFS, on all available states other than the current target DLS_TGT. This deviation reduces the usable speed range, removing from it a margin between the actual achievable values and the calculated limit speeds, specified to the downstream functions for selecting the target states using this information. These consolidated displacement limit speed values are called respectively DLS_MIN_RELIA_VH_SPD_CS and DLS_MIN_RELIA_VH_SPD_CS, with:

- DLS_MIN_RELIA_VH_SPD_CS = DLS_MIN_RELIA_VH_SPD_RAW + SPD_OES except for the coordinate of the current target DLS_TGT where DLS_MIN_RELIA_VH_SPD_CS = DLS_MIN_RELIA_VH_SPD_RAW, and

- DLS_MAX_RELIA_VH_SPD_CS = DLS_MAX_RELIA_VH_SPD_RAW - SPD_OES except for the coordinate of the current target DLS_TGT, where DLS_MAX_RELIA_VH_SPD_CS = DLS_MAX_RELIA_VH_SPD_RAW.

The second consolidation aims to impose a specific minimum value on a state of the kinematic chain, in the case where this state is attainable thanks to the sliding of a coupler located between the machine or heat engine used and the wheel; the specific value makes it possible to reach a kinematic chain state, at a vehicle travel speed lower than the calculated nominal value. A minimum speed can also be imposed on the states of the kinematic chain allowing the vehicle to take off from zero speed and using only the electric machine to pull the vehicle. The gross minimum speeds DLS_MIN_RELIA_VH_SPD_CS) are thus consolidated by imposing a specific minimum value on them on the states of the kinematic chain, which can be reached, thanks to the sliding of a coupler, at a displacement speed lower than that which is calculated nominally or on the states of the kinematic chain allowing the vehicle to take off from zero speed and using only the electric machine to pull the vehicle.

An adjustment parameter DLS_VS_MIN_ENA is used for this; this parameter is a vector specifying a replacement value for each state. DLS_VS_MIN_VALUE, and to determine whether the calculated minimum speed value DLS_MIN_RELIA_VH_SPD_CS should be used, or replaced by the specified replacement value.

If the X coordinate of the vector DLS_VS_MIN_ENA is equal to 1, then the value of the X coordinate of

DLS_MIN_RELIA_VH_SPD is equal to the value of the X coordinate of DLS_VS_MIN_VALUE. Otherwise (DLS_VS_MIN_ENA = 0), the value of the X coordinate of DLS_MIN_RELIA_VH_SPD is equal to the value of the X coordinate of DLS_MAX_RELIA_VH_SPD_CS consolidated. Through all of these functions, the minimum and maximum vehicle travel speeds making it possible to guarantee mechanical reliability in terms of the speed of rotation of the traction units on each of the states of the kinematic chain are calculated automatically in real time. Their values allow any strategy using this information, in particular the computing units ensuring the selection of the target states of the GMP, to be aware of these limits for their own operations.

The advantages of the method are numerous. The strategy implemented is indeed perfectly transversal. It can be adapted on any vehicle having a hybrid / electric / conventional powertrain with an automatic transmission with discrete ratios, at least one electric state one thermal state and / or hybrid.

Claims

1. Method for selecting the state setpoint of a vehicle kinematic chain connecting several traction units including a heat engine and at least one electric machine to the vehicle wheels by means of a transmission, from among a set of '' states present in the transmission defined by different combinations of couplers and reducers thereof to ensure the transfer of torque from the heat engine and / or the electric machine towards the wheels on one or more gear ratios, the selection of the state setpoint including a step of determining the minimum and maximum vehicle travel speeds (DLS_MIN_RELIA_VH_SPD) and (DLS_MAX_RELIA_VH_SPD) making it possible to guarantee the mechanical reliability of the traction units on each of the available states of the kinematic chain, characterized in that :

- the maximum displacement speed (DLS_MAX_EM_VH_SPD) authorized by an electric machine depends on the maximum possible speed on the electric machine (MAX_EM_SPD), the wheel radius (WHEEL_RAD) and the gear ratio

(DLS_EM_RATIO) between the electric machine and the wheel, and

- the minimum and maximum authorized travel speeds depending on the heat engine (DLS_MIN_ICE_VH_SPD) and

(DLS_MAX_ICE_VH_SPD), depend on the minimum and maximum speed possible on the heat engine (MIN_ICE_SPD, MAX_ICE_SPD), the wheel radius (WHEEL_RAD), and the gear ratio (DLS_ICE_RATIO) between the heat engine and the wheel.

2. State setpoint selection method according to claim 1, characterized in that the raw values of the displacement speeds (DLS_MIN_RELIA_VH_SPD_RAW) and (DLS_MAX_RELIA_VH_SPD_RAW) are determined as a function:

- maximum authorized movement speeds (DLS_MAX_EM_VH_SPD) by an electric machine,

- minimum and maximum travel speeds authorized (DLS_MIN_ICE_VH_SPD) and (DLS_MAX_ICE_VH_SPD) by the heat engine.

3. State setpoint selection method according to claim 1 or 2, characterized in that the raw values of the minimum and maximum speeds of movement of the vehicle (DLS_MIN_RELIA_VH_SPD_RAW) and (DLS_MAX_RELIA_VH_SPD_RAW) are determined on each available state, as a function of the energy type of traction (DLS_TYP_LIST (X)) of this state.

4. State setpoint selection method according to claim 2 or 3, characterized in that when the GMP has only one electric machine, the maximum speed limit (MAX_EM_SPD) is not included in the value of the maximum engine speed (MAX_ICE_SPD), the maximum gross speed of the vehicle (DLS_MAX_RELIA_VH_SPD_RAW (X)) is the minimum value between the maximum speeds

(DLS_MAX_ICE_VH_SPD (X)) and (DLS_MAX_EM_VH_SPD (X)) authorized by the heat engine and by the electric machine.

5. State setpoint selection method according to claim 4, characterized in that in the other provisions of the GMP, the gross maximum speed of the vehicle (DLS_MAX_RELIA_VH_SPD_RAW (X)) is equal to the maximum speed authorized by the heat engine (DLS_MAX_ICE_VH_SPD (X).

6. Method for selecting a state setpoint according to one of claims 2 to 5, characterized in that the gross minimum and maximum speeds of movement of the vehicle

(DLS_MIN_RELIA_VH_SPD_RAW) and (DLS_MAX_RELIA_VH_SPD_RAW) are consolidated respectively by adding or subtracting a speed difference (SPD_OES) on all available states other than the current target (DLS_TGT).

7. State setpoint selection method according to one of claims 2 to 5, characterized in that the minimum and maximum speeds (DLS_MIN_RELIA_VH_SPD_CS) and (DLS_MAX_RELIA_VH_SPD_CS) are consolidated by imposing a specific minimum value on the states of the kinematic chain, which are attainable, thanks to the sliding of a coupler, at a travel speed slower than that which is nominally calculated or on the states of the kinematic chain allowing the take-off of the vehicle from a zero speed and using only the electric machine to pull the vehicle.

8. State setpoint selection method according to one of the preceding claims, characterized in that the states of the vector (DLS_ TYP_LIST) include at least one neutral state, one electrical state, and one thermal state.