METHOD FOR CONTROLLING A HYBRID VEHICLE POWERTRAIN COMPRISING A PARKING LOCK

Abstract

A method for controlling a hybrid motor vehicle powertrain comprising an internal combustion engine (10) and an electric traction machine (8), the vehicle being equipped with a gear lever (16) acting on a parking lock (18) to control a park position, a neutral position, and driving positions, and equipped with a powertrain activation control (26) that starts the internal combustion engine. During a powertrain activation cycle requested by the driver, if the driver moves the gear lever (16) to change the state of the parking lock (18), this movement either authorizes or prevents the activation or termination of the parking lock, and also authorizes or prevents a change of state of the parking lock. Figure 1

Description

Title of the invention: METHOD FOR CONTROLLING A VEHICLE POWERTRAIN HYBRID WITH PARKING LOCK

[0001] The present invention relates to a method for controlling a powertrain of a hybrid motor vehicle comprising a parking lock, as well as a hybrid vehicle equipped with devices implementing such a method.

[0002] Motor vehicles with an automatic gearbox generally include in this gearbox a parking lock, called "Park Lock" in English, comprising a finger which in an engagement movement descends into a notch of a crown connected to the driving wheels of the vehicle, so that when it is actuated it locks this crown and thus ensures complete locking of the wheels, and of the vehicle when it is parked. In a release movement the finger is raised to release the wheels.

[0003] A type of gear change mechanism for controlling an automatic gearbox, presented in particular by document US-A-5220984, comprises a gear lever which controls parking, reverse, neutral and forward positions, equipped with a ratchet-shaped tooth which engages in a notch in order to hold this lever in the parking position.

[0004] A solenoid mounted on the lever allows the tooth to be locked to prevent it from coming out of the notch under certain conditions, in particular if the driver has not applied the vehicle's brakes in order to keep the vehicle immobilized during unlocking and to avoid uncontrolled movement which could cause accidents.

[0005] Furthermore, hybrid vehicles comprise a powertrain comprising at least one electric traction machine, and a thermal engine started with its own electric machine, with this traction machine or with these two engines, the driver activating this group in order to prepare a movement of the vehicle with electric or thermal driving. For this, the driver has a control, such as a key or a start button, which can carry out, depending on the position of the gear lever, all the actions on the powertrain allowing the mobility of the vehicle, in particular the activation of the electric machines and the starting of the thermal engine. The actuation of the powertrain is permitted in particular with a gear lever in the parking position P which gives the parking lock, or in the neutral position N which gives its unlocking, the powertrain not being able to drive the vehicle in these two cases.

[0006] However, after a request to activate the powertrain, the driver can immediately move the gear lever with a command requesting a change in the state of the parking lock, while the activation of this group is not complete. For example, the driver can request a change from the parking position to the neutral position or to a driving position which requires unlocking, or request a change to the parking position which requires locking.

[0007] In addition, certain transmissions use a common supply of hydraulic pressure to control a component necessary for activation, such as a clutch, and the parking lock, this supply being able to have insufficient power to simultaneously operate these two components.

[0008] In particular, hydraulic pressure can be used to control the tightening of a drive clutch of the thermal engine and the movement of the parking lock giving its change of state, simultaneous actions on these two members causing a pressure drop disrupting their operations. In particular, a failure can be obtained giving both an activation of the powertrain and an opening of the parking lock, which does not secure the immobilization of the vehicle.

[0009] The present invention aims in particular to avoid these problems of the prior art.

[0010] To this end, it proposes a method for controlling a powertrain of hybrid motor vehicle comprising a thermal engine and an electric traction machine, the vehicle being equipped with a gear lever acting on a parking lock, to control a parking position, a neutral position and driving positions, and equipped with a control for activating the powertrain starting the thermal engine, this method being remarkable in that during a powertrain activation cycle requested by the driver, if this driver makes a movement of the gear lever requesting a change of state of the parking lock, following this movement it authorizes or prohibits the activation cycle or its finalization, and it authorizes or prohibits a change of state of the parking lock.

[0011] An advantage of this method is that it allows, depending on the requests received, to prioritize one action over another, the activation of the powertrain, or the engagement or disengagement of the requested parking lock, while maintaining high security. In particular in the case of a low energy level to carry out both actions at the same time, one is prioritized to avoid failure of the other action.

[0012] The method ensures a high level of security, in particular by being able to maintain both a parking lock and a stop of the actuation to keep this double protection guaranteeing the immobilization of the vehicle in the event of technical failure of one of these means.

[0013] The method for controlling the powertrain according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0014] Advantageously, the change of position of the gear lever moving it from the parking position to a driving position, the method prohibits the release of the parking lock, and it interrupts if necessary and prohibits any activation of the powertrain.

[0015] Advantageously, by changing the position of the gear lever, moving it from the neutral position to a driving position, the method prevents the parking lock from being released, and if necessary, interrupts and prevents any activation of the powertrain.

[0016] Advantageously, by changing the position of the gear lever, moving it from the parking position to the neutral position, the method allows the powertrain to be activated, enabling it to be finalized.

[0017] In this case, advantageously during the activation of the powertrain, it simultaneously applies a time delay on the change of state of the parking lock in order to check at the end of this time delay whether this activation is complete before authorizing a change of state of this parking lock.

[0018] Furthermore, if the actuation is not completed at the end of the first time delay, it applies a second time delay to check at the end whether the actuation is completed, and if it is not completed it completely prohibits the release of the parking lock until the driver exerts a new maneuver on the gear lever.

[0019] Advantageously, the change in position of the gear lever moving it from the neutral position to the parking position, the method authorizes the engagement of the parking lock, and as long as this engagement is not complete it prohibits the activation of the powertrain.

[0020] The invention also relates to a motor vehicle equipped with devices implementing a control method comprising any one of the preceding characteristics, remarkable in that the powertrain comprises a clutch arranged between the heat engine and an electric machine for starting this heat engine.

[0021] In particular, the clutch and the parking lock can be actuated from the same hydraulic pressure supply.

[0022] The invention will be better understood and other characteristics and advantages will appear more clearly on reading the description below given by way of example, with reference to the appended drawings in which:

[0023] [Fig-1] is a diagram showing the electronic supervisors implemented by the method according to the invention;

[0024] [Fig.2] is a functional diagram of the method according to the invention; and

[0025] [Fig.3] is a table showing the prioritization in different cases of displacement of the gear lever.

[0026] [Fig.l] shows for a hybrid motor vehicle, a supervisor of the powertrain 2 comprising a supervisor of the activation function of this powertrain 4, and a supervisor of the parking blocking function 14. The group activation supervisor 4 exchanges information with an electric traction machine 8, a thermal engine 10 connected to the kinematic chain by a clutch, and an activation control actuated by the driver 26 using in particular a key or a start button.

[0027] The parking lock supervisor 14 exchanges information with a speed control lever 16, and a parking lock 18 which can be arranged in the transmission of the thermal engine or elsewhere, making it possible to lock the wheels of the vehicle.

[0028] The actuation supervisor 4 sends to the parking lock supervisor 14 information on the state of the powertrain 20, the latter supervisor sending to the actuation supervisor information on the position of the gear lever 22 and on the state of the parking lock 24.

[0029] The hybrid vehicle may be rechargeable on an electricity distribution network, or non-rechargeable, and comprise one or more electric traction machines which may be integrated into the transmission of the thermal engine arranged at the front, or arranged on the rear axle.

[0030] The transmission of the powertrain may in particular comprise a clutch for driving the thermal engine from an electric machine to ensure its starting, by means of a clutch engaged by a hydraulic control pressure. The parking lock may also comprise a hydraulic control.

[0031] In the case where the clutch and the parking lock use the same power source presenting difficulties in simultaneously implementing the two functions, it is important to provide priority for one control over the other to best ensure the speed of the requested actions, and safety.

[0032] [Fig.2] shows a functional diagram comprising a first step 30 of request for activation of the powertrain coming from control 26 operated by the driver. The activation of the powertrain performs various operations enabling the vehicle to move, for example activating the electric traction machine 8 or starting the thermal engine 10.

[0033] A second following step 32 comprises the detection of a change in position of the gear lever 16 actuated by the driver.

[0034] A third following step 34 comprises the identification of a request for change of state of the parking lock 18 caused by the change of position of the gear lever detected in the second step 32.

[0035] A fourth following step 36 carries out a condition on the identification carried out in the third step 34. In the case where the fourth step 36 detects an absence of a NO request for a change of state of the parking lock 18, there is then a fifth following step 38 of authorization of the complete activation of the powertrain.

[0036] In the case where the fourth step 36 detects a YES request for a change of state of the parking block 18, there is then a sixth following step 40 of analysis of the priorities to decide on the end of the activation cycle before a possible authorization to move the parking block, or the interruption of the activation before this possible authorization.

[0037] [Fig. 3] shows in a first column the change of position of the gear lever 16 made by the driver. The second column PLockl shows the authorization given by the actuation supervisor 4 transmitted to the parking blocking supervisor 14, concerning the change of state of the parking blocking 18, for a release agreement PLock=Deg or for an engagement agreement PLock=Eng.

[0038] The third MEA column shows the authorization to finalize the activation of the powertrain, for an authorization MEA=1 and for a refusal of authorization MEA=0.

[0039] The fourth column PLock2 presents a following authorization for changing the state of the parking lock given by the actuation supervisor 4, after its first change of state or after the end of actuation.

[0040] The first line 50 presents in its first column a change of position PD / R which moves the gear lever from the parking position P to a forward driving position D or reverse R, requiring a release of the parking lock to allow this driving.

[0041] The second column indicates that the actuation supervisor 4 transmits to the parking blocking supervisor 14 the prohibition of clearing the parking block PLock=Eng.

[0042] The third column indicates that the actuation supervisor 4 interrupts the current actuation and prohibits any actuation MEA=0.

[0043] The fourth column indicates that only if the gear lever returns to the neutral or parking position N / P, then the actuation supervisor 4 authorizes an actuation of the powertrain MEA=1

[0044] In this way, in a driving position D, R, both the parking lock is maintained and the powertrain is prevented from being activated, forming a double safety feature which, even in the event of a failure, ensures that the vehicle is immobilized.

[0045] A subsequent authorization to activate the powertrain can only be given after a movement of the lever towards the neutral position N or parking P, the only positions authorized for this activation because they do not provide the possibility of moving the vehicle.

[0046] The second line 52 presents in its first column a change of position ND / R which moves the gear lever from the neutral position N to a forward driving position D or reverse R, requesting a release of the parking lock.

[0047] The second column indicates that the action supervisor 4 does not authorize this release of the parking block PLock=Eng, by sending information to the parking block supervisor 14 which prohibits this action.

[0048] The third column indicates that the actuation supervisor 4 interrupts the current actuation and prohibits any actuation MEA=0.

[0049] The fourth column indicates, as for the previous line 50, that only if the gear lever returns to the neutral or parking position N / P, then the actuation supervisor 4 authorizes actuation of the powertrain MEA=1

[0050] A parking release ban is also provided, preventing any movement of the vehicle. A subsequent authorization to activate the powertrain can only be given after movement of the lever towards the neutral position N or parking position P.

[0051] The third line 54 presents in its first column a change of position PN which moves the gear lever from the parking position P to the neutral position N, requesting a release of the parking lock.

[0052] The third column indicates that the action supervisor 4 authorizes the action MEA=1, which has priority.

[0053] The second column indicates that the actuation supervisor 4 requests the parking blocking supervisor 14 for a first time delay templ to check the end of the actuation MEA OK before authorizing the release of the parking block Plock=Deg. At the end of the first time delay templ if the actuation is not completed MEA NOK, it requests a second time delay temp2 to wait for the end of the actuation. After this second time delay temp2, if the actuation is not completed then it completely prohibits the release of the parking lock 12 until the driver performs a new maneuver on the gear lever 16.

[0054] Alternatively, a single time delay templ could be used before applying the complete prohibition of disengaging the parking lock 12 until the new maneuver on the gear lever 16.

[0055] Prioritization of the activation of the powertrain is ensured, arrival at the neutral position N not giving the possibility of rolling the vehicle, the release of the parking lock is not a priority.

[0056] The fourth line 56 presents in its first column a change of position NP which moves the gear lever from the neutral position N to the parking position P, requesting engagement of the parking lock.

[0057] The second column indicates that the activation supervisor 4 authorizes this engagement of the parking lock PLock=Eng by sending information to the parking lock supervisor 14.

[0058] The third column indicates that the actuation supervisor 4 interrupts the actuation in progress and prohibits any actuation MEA=0.

[0059] The fourth column indicates that as long as the parking lock is not engaged PLock NOK, there is a prohibition on activation of the powertrain MEA=0.

[0060] Prioritization of the engagement of the parking lock or the activation of the powertrain is ensured, which avoids simultaneous action on these two functions which could lead to a failure, in particular in the case of a common power supply for these two functions delivering insufficient power.

Claims

Claims

1. Method for controlling a powertrain of a hybrid motor vehicle comprising a heat engine (10) and an electric traction machine (8), the vehicle being equipped with a gear lever (16) acting on a parking lock (18), to control a parking position (P), a neutral position (N) and driving positions (D, R), and equipped with a powertrain actuation control (26) carrying out a start of the heat engine, characterized in that during a powertrain actuation cycle requested by the driver, if this driver performs a movement of the gear lever (16) requesting a change of state of the parking lock (18), following this movement he authorizes or prohibits the actuation or its finalization, and he authorizes or prohibits a change of state of the parking lock (18),in which when the change of position of the gear lever (16) is a movement from the neutral position (N) to the parking position (P), it authorizes the engagement of the parking lock (PLock=Eng), and as long as this engagement is not completed it prohibits the activation of the powertrain (MEA=0).,

2. Control method according to claim 1, characterized in that the change of position of the gear lever (16) moving it from the parking position (P) to a driving position (D, R), it prohibits the release of the parking lock (PLock=Eng), and it interrupts if necessary and prohibits any activation of the powertrain (MEA=0).

3. Control method according to claim 1 or 2, characterized in that the change of position of the gear lever (16) moving it from the neutral position (N) to a driving position (D, R), it prohibits the release of the parking lock (PLock=Eng), and it interrupts if necessary and prohibits any activation of the powertrain (MEA=0).

4. Control method according to any one of the preceding claims, characterized in that the change of position of the gear lever (16) moving it from the parking position (P) to the neutral position (N), it authorizes the activation of the powertrain (MEA=1) by allowing its finalization.

5. Control method according to claim 4, characterized in that during the activation of the powertrain, it simultaneously applies a time delay (templ) on the change of state of the parking lock (18) to check at the end of this time delay whether this activation is finished (MEA OK) before authorizing a change of state of this parking lock (PLock=Deg).

6. Control method according to claim 5, characterized in that if the actuation is not completed at the end of the first (templ), it applies a second time delay (temp2) to check at the end if the actuation is completed, and if it is not completed (MEA NOK) it completely prohibits the release of the parking lock (PLock=Eng) until the driver exerts a new maneuver on the gear lever (16).

7. Motor vehicle equipped with devices implementing a control method according to any one of the preceding claims, characterized in that the powertrain comprises a clutch arranged between the heat engine (10) and an electric machine for starting this heat engine (10).

8. Motor vehicle according to claim 7, characterized in that the clutch and the parking lock (18) are actuated from the same hydraulic pressure supply.

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