Method for selecting targets for the condition of an automatic transmission drivetrain - Patents.com

Abstract

The present invention relates to a method for selecting a target (CRT_GBX_DLS_TGT) for the state of the drivetrain of an automatic transmission during a transition phase between a current state and a state that is initially adopted as a target among many other states in order to meet the driver's acceleration requirements, the method being characterized in that the arbitration between maintaining the initial target and selecting a new target is activated when a change of state between the current state and the initial state is currently being performed in the transmission and when the initial target no longer complies with the driver's acceleration requirements. [Selected Figure] Figure 1

Description

[Technical field]

[0001] The present invention relates to the control of drivetrain state changes on electric / hybrid or heat engine vehicle transmissions.

[0002] More specifically, the subject of the invention is a method for selecting a target state of an automatic transmission drivetrain during a transition phase between a current state and a state initially adopted as a target among several other states in order to satisfy an acceleration request from a driver. [Background technology]

[0003] On a vehicle equipped with a gearbox with individual gear ratios, whether the vehicle is electric / hybrid or thermal engine, the drivetrain state change phases can be defined as combinations of couplers and reducers specific to a given vehicle architecture. Depending on the complexity of the architecture, these transition phases can last up to several seconds.

[0004] The change in drivetrain conditions can last for several seconds, meaning that in some cases the initial target is discarded during the transition in favor of a new target. Target changes can occur for a variety of reasons, one of which is that the speed of vehicle movement becomes too high during the transition, creating reliability issues or other hazards.

[0005] When the change in target during a transition is due to an increased acceleration request from the driver, this change can have a particularly significant effect on the vehicle's behavior and how that behavior is perceived.

[0006] A driver who requests the acceleration of the vehicle expects it within a reasonable time with a satisfactory level of execution. During a state change, the box is in a transition phase. The box may even have several transition stages to follow before reaching its target. If the request changes in the transition phase, the box may aim at a new target whose execution time was not initially predictable. Based on the new target of the box, the box may provide the torque required for this acceleration at a different level. The selection of a new target by the box during an already started state change therefore has a significant impact on the delay and level at which the acceleration requested by the driver is obtained.

[0007] From US publication 8,944,957 a method is known which makes it possible to determine whether the currently implemented target gear ratio must be erased after an increase in the torque demand. The method also shows how a new target for the gearbox is implemented. However, this publication does not specify how the latter is selected.

[0008] GB 2 433 301 describes a specific method for determining the gear ratio of a dual clutch gearbox based on a speed threshold and the position of the accelerator pedal. The selection is made individually, without the option between multiple targets or the possibility of changing the target during the transition.

[0009] However, none of these publications specifies how to define the best target drivetrain state in order to obtain the acceleration requested by the driver during a drivetrain state change phase that is already in progress. Summary of the Invention

[0010] The present invention is directed to selecting a target automatic transmission gear ratio in response to a request from a driver, according to criteria of response time and acceleration strength.

[0011] To this end, arbitration between keeping the initial target and selecting a new target is activated if the two following conditions are met: The change of state between the current state and the initial target is currently being performed in the transmission. The initial target no longer complies with the acceleration constraints requested by the driver.

[0012] Preferably, when the initial target CRT_GBX_DLS_TGT is evicted during execution, A list of states eligible to become new targets is determined by assigning priority factors to those states according to the arbitration AVL_DLS_AFTR_DRB linked to the brio constraint; A new target CRT_GBX_DLS_TGT is selected from among the eligible states, A new target is imposed on the drive train until it is fully executed.

[0013] The method is applicable to any thermal / hybrid / electric vehicle equipped with an automatic transmission with discrete gear ratios. The method imposes arbitration between the available states, i.e. allowing some of them and prohibiting others. A series of successive arbitrations makes it possible to define a set of states that qualify as targets to be executed by the transmission. The arbitrations can be made in a non-limiting manner: The selected driving mode (forward, reverse, etc.), Reliability limits for the speed of traction devices (electrical machines, heat engines, etc.), or Brio constraints determined by accelerator pedal position or external demands It can be related to.

[0014] Other features and advantages of the present invention will become apparent from the following description of specific embodiments of the invention, which proceeds with reference to the accompanying drawings. [Brief description of the drawings]

[0015] [Figure 1] 1 is a flow chart of the strategy developed. [Diagram 2] FIG. 13 is a timing diagram of an example application of the developed procedure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In the following description, the preliminary ruling for new target selection is a ruling related to BRIO: In this example, if a state is not capable of applying the acceleration request from the driver, this state is considered ineligible for selection.

[0017] The progress of the operations is illustrated by Fig. 1. They consist in selecting a new target state of the drivetrain CRT_GBX_DLS_TGT according to some conditions while the transmission is already in a transition phase between the current state and an initial target chosen among several states in order to satisfy an acceleration request from the driver. The method is divided into several steps. The sequence of the method leads to the determination of a list of states of the drivetrain that allow compliance with the acceleration constraints requested by the driver in terms of response time and strength. The eligibility list of the drivetrain states before a possible decision linked to a brio constraint is called AVL_DLS_BFR_DRB. The eligibility list is established in anticipation of a possible change of the target that will become necessary for brio reasons during a change of state already undertaken. The list of eligible drivetrain states after a decision linked to a brio constraint is AVL_DLS_AFTR_DRB.

[0018] The purpose of step F1 is to determine whether arbitration between states that is eligible to satisfy an acceleration request from the driver during a state change should be activated. The corresponding activation request is DLS_TGT_CGE_DRB_REQ. This request is valid if the following two conditions are met: A drivetrain state change is currently being performed in the transmission (current state CRT_GBX_DLS differs from target CRT_GBX_DLS_TGT). The target state CRT_GBX_DLS_TGT is considered ineligible because it does not comply with the acceleration constraints requested by the driver, i.e., the target state CRT_GBX_DLS_TGT was eligible before the arbitration related to the brio constraints (list AVL_DLS_BFR_DRB) but is no longer eligible after the arbitration (list AVL_DLS_AFTR_DRB).

[0019] In summary, the decision between staying with the original selection and choosing a new target is: a change of state between the current state and the initial target is currently being performed in the transmission; The initial target no longer complies with the acceleration constraints requested by the driver It is activated if

[0020] Otherwise, the ruling is not activated.

[0021] The purpose of step F2 is to select the drivetrain state that will best satisfy the acceleration requests from the driver during the state change. The arbitration activation event is DLS_TGT_DRB_STY_ENA. If the activation request DLS_TGT_CGE_DRB_REQ is valid, the arbitration is activated and DLS_TGT_DRB_STY_ENA is true. If the deactivation request DLS_TGT_CGE_DRB_NOREQ is valid, the arbitration is deactivated and DLS_TGT_DRB_STY_ENA is false.

[0022] Step F3 consists in determining when the arbitration must be deactivated. A deactivation request DLS_TGT_CGE_DRB_NOREQ becomes valid if the strategy is active (DLS_TGT_DRB_STY_ENA=true) and if one of the two following conditions is met: The new target CRT_GBX_DLS_TGT is rejected before arbitration, or A new target is reached and the new target is the current state of the drivetrain for a determined period of time.

[0023] Step F4 consists in assigning priority coefficients to the other states based on the current state CRT_GBX_DLS. In this ranking, called DLS_Ranking, the lowest coefficient is given to the optimal state and the highest coefficients to the other states.

[0024] Step F5 consists in establishing a list of optimal states AVL_DLS_AFTR_DRB_CGE_MIND, which allows compliance with the acceleration constraints requested by the driver during the change of states, in terms of response time and intensity. The optimal states allow the transmission to have an optimal target. A new target CRT_GBX_DLS_TGT is selected from the list of optimal states AVL_DLS_AFTR_DRB_CGE_MIND, established according to compliance with some acceleration constraints. If DLS_TGT_DRB_STY_ENA is false, the list of eligible states at the end of this arbitration corresponds to the preceding eligibility list AVL_DLS_AFTR_DRB. If DLS_TGT_DRB_STY_ENA is true, the operation is divided as follows:

[0025] a) When a target CRT_GBX_DLS_TGT is evicted during execution for Brio reasons, first the priority states and the states eligible to become the new target are determined. For that, the lowest value of the coefficient of an eligible state after the award related to the Brio constraint (DLS_AVL_AFTR_DRB) is selected from the list of coefficients established in step F4 (DLS_Ranking). Among the states with this coefficient, only those states that were already eligible in the previous award (AVL_DLS_AFTR_DRB) are kept. The new target CRT_GBX_DLS_TGT is Decontamination / The last one is selected from the list AVL_DLS_AFTR_DRB_CGE_MIND according to the consumption constraints.

[0026] b) When a new target CRT_GBX_DLS_TGT is determined, only the new target is eligible in the list AVL_DLS_AFTR_DRB_CGE_MIND to avoid the final selection of another state with the same priority. The list AVL_DLS_AFTR_DRB_CGE_MIND allows compliance with the driver's intentions regarding reaction times and acceleration strength.

[0027] In other words, when the initial target (CRT_GBX_DLS_TGT) is evicted during execution, The list of states eligible to become new targets is determined by assigning priority factors to those states according to the arbitration related to the BRIO constraint (AVL_DLS_AFTR_DRB); A new target (CRT_GBX_DLS_TGT) is selected from among the eligible targets, A new target is imposed on the drive train until it is fully executed.

[0028] FIG. 2 illustrates the application of the method to an automatic transmission with discrete gear ratios having six forward drivetrain states.

[0029] At time T1, the target state of the drivetrain CRT_GBX_DLS_TGT changes from 6 to 5, but the current state CRT_GBX_DLS is 6, at which moment the state change begins.

[0030] At time T2, the current target CRT_GBX_DLS_TGT was eligible before the arbitration related to the BRIO constraint (list AVL_DLS_BFR_DRB), but is considered ineligible after the arbitration (list AVL_DLS_AFTR_DRB). This target is rejected. At T2, the procedure activation request DLS_TGT_CGE_DRB_REQ becomes true in function F1, which accompanies the procedure activation DLS_TT_DRB_STY_ENA in function F2.

[0031] Between T2 and T3, function F4 assigns priority coefficients to the different states of the drivetrain according to the current state CRT_GBX_DLS by list DLS_Ranking, such that state 1 has coefficient 3, state 2 has coefficient 4, etc. From the ranking DLS_Ranking and from the list AVL_DLS_AFTR_DRB of the eligibility of the states after arbitration related to the Brio constraint, function F5 determines the smallest available coefficient, i.e. only states 2, 3 and 4 are available, with coefficient 4, coefficient 1 and coefficient 1 respectively. The smallest available coefficient is 1.

[0032] As mentioned above, arbitration makes it possible to define the states that allow compliance with the acceleration constraints requested by the driver in terms of response time and strength. Arbitration allows only the states with the lowest observed coefficient value. In this example, state 2 is prohibited since it has a coefficient of 4, while states 3 and 4 are allowed since their coefficients are equal to 1. The list of eligible states is AVL_DLS_AFTR_DRB_CGE_MIND.

[0033] This ruling and the corresponding authorization remain in effect until the selection by the gearbox of a new target state from among the states deemed eligible.

[0034] At time T3, target CRT_GBX_DLS_TGT changes from state 5 to state 4. Between T3 and T4, function F5 no longer enables the current target CRT_GBX_DLS_TGT in list AVL_DLS_AFTR_DRB_CGE_MIND, so the transmission is forced to remain at that target.

[0035] At time T4, the box has completed executing target CRT_GBX_DLS_TGT. The current state of the train, CRT_GBX_DLS, has changed from value 6 to value 4. By time T5, the only target enabled by function F5 is still the target state, which is the current state.

[0036] At time T5, the current state CRT_GBX_DLS corresponds to the target CRT_GBX_DLS_TGT since T4. Function F3 requests the deactivation of the arbitration by the request DLS_TGT_CGE_DRB_NOREQ to allow the gearbox to select another possible target. This request deactivates the procedure in function F2 and the activation of the procedure DLS_TGT_DRB_STY_ENA changes to false. From the deactivation of the procedure, the eligible states at the end of the procedure in AVL_DLS_AFTR_DRB_CGE_MIND are the eligible states after the arbitration AVL_DLS_AFTR_DRB related to the Brio constraint. In this example, these states are state 3 and state 4.

[0037] The main advantages of the present invention are the minimal adjustments required in the arbitration procedure and the cross-sectional nature of the method which can be adopted for any vehicle equipped with an automatic gearbox with individual gear ratios.

Claims

1. 1. A method for selecting a target state (CRT_GBX_DLS_TGT) of an automatic transmission drivetrain during a transition between a current state and an initial target, which is a state that is initially adopted as a target among several other states to satisfy an acceleration request from a driver, comprising a request for activation of an arbitration (DLS_TGT_CGE_DRB_REQ) for determining whether it is appropriate to exclude the initial target and select a new target, a change in state between the current state and the initial target is currently being performed in the automatic transmission; and Validated when the initial target no longer complies with acceleration constraints regarding acceleration response time and acceleration strength requested by the driver; When the initial target is evicted during execution, determining an eligibility list of states eligible to become new targets by assigning priority factors to states eligible to become new targets according to the current state; The lowest priority factor is given to the optimal state and the highest priority factor is given to the other states; 13. A method for selecting a drivetrain target state (CRT_GBX_DLS_TGT), wherein the eligibility list is established in anticipation of possible changes in the target that may be required due to external demands, such as accelerator pedal position, during a change in state.

2. The new target (CRT_GBX_DLS_TGT) is selected from among the states included in the eligibility list; The new target is imposed on the drive train until it is fully executed. thing The method of claim 1 , further comprising:

3. 3. A method according to claim 2, characterized in that said new target (CRT_GBX_DLS_TGT) is selected from said list of optimal states (AVL_DLS_AFTR_DRB_CGE_MIND) established according to compliance with said acceleration constraint.

4. 4. Selection method according to claim 2 or 3, characterized in that the new targets are selected according to a decontamination criterion and / or a criterion of electricity or heat consumption.

5. 5. A method according to claim 1, wherein when the new target (CRT_GBX_DLS_TGT) is selected, the new target (CRT_GBX_DLS_TGT) remains the only eligible state in the list of optimal states (AVL_DLS_AFTR_DRB_CGE_MIND).

6. A request to deactivate the arbitration (DLS_TGT_CGE_DRB_NOREQ), The selected new target is eliminated during arbitration; or The selected new target is executed and remains in the current state of the drivetrain for a defined period of time.

6. The method according to claim 1, further comprising the step of:

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