Method and system for controlling hybrid motor vehicle according to traffic lights

Abstract

The invention relates to a method for controlling a hybrid vehicle, comprising the following steps: in a first step (1), receiving information from traffic lights; in a second step (2), determining the active signal being displayed and the time until the first traffic light on the path of the vehicle changes from the information from the traffic lights; and in steps (3, 4, 5, 6, 7, 8) comparing the time until the traffic lights change, the speed of the vehicle and the maximum permissible speed of the motor vehicle on the road in use, and subsequently controlling the energy management strategy and notifying the driver of the action to be taken in order to limit the waiting time at the traffic lights and the energy consumed by sitting under the traffic lights.

Description

Technical Field

[0001] The technical field of the invention is the control of motor vehicles, in particular the control of such vehicles equipped with a hybrid powertrain.

[0002] In order to optimize the vehicle's energy consumption, it is possible to avoid stopping or slow down when approaching a traffic light that signals a mandatory stop, to predict the change from a traffic light to a signal indicating a mandatory stop, in order to cut off the injection to the thermal engine, or to limit the operation of the electric motor, or even to allow the vehicle to idle. To do this, it is necessary to know in advance the time of the change of state of the traffic light (the time of the transition (passage) between the signal states).

[0003] For a hybrid vehicle comprising a thermal engine and at least one electric motor, the route, speed profile and power demand at the wheels enable the overall consumption to be optimized. With the new technology, future information is available, in particular information on the state and duration before changing the traffic light.

[0004] In manual mode, the driver alone decides on the acceleration and deceleration of the vehicle by reading the suggestions displayed on the instrument panel when approaching traffic lights.

[0005] On the other hand, the hybrid monitor controls the torque of the thermal engine and the electric motor as well as stops and starts the thermal engine.

[0006] The energy management strategy needs to be optimized based on the status of traffic lights on the vehicle's route. Background Art

[0007] The prior art includes FR2101753, which describes a method for controlling an automatic gearbox by cleverly controlling the gearbox to provide strong power when the driver fails to comply with the instructions given when approaching a traffic light.

[0008] The document applies to any vehicle with an automatic transmission and its purpose is to avoid unnecessary overconsumption of fuel due to driver behavior. However, it does not describe the application to hybrid vehicles and the consideration of multiple drive sources. Summary of the invention

[0009] The invention relates to a method for controlling a motor vehicle equipped with a hybrid powertrain comprising a thermal engine and at least one electric motor, controlled by a predetermined energy management strategy, and the vehicle also comprising a computer, a human-machine interface for displaying information to the driver and means for communicating with at least one traffic light, the method comprising the following steps:

[0010] The computer receives information from the traffic light; the computer determines the distance to the traffic light, the active signal displayed by the traffic light from a first signal associated with an intersection authorization and a second signal associated with an intersection prohibition, and the duration until the traffic light signal is changed based on the received information; the computer compares the time until the traffic light signal is changed with the time covering the distance to the traffic light; the computer temporarily modifies the energy management strategy based on the comparison result and sends an indication to the driver of at least one action to be taken consistent with the modification of the energy management strategy, thereby limiting the energy consumed until crossing the traffic light.

[0011] When the traffic light displays a second signal, and when the time to cover the distance to the traffic light at the vehicle's current speed is less than the time for the signal to change (which in turn is less than the time required for the vehicle to cover the distance to the traffic light in freewheel mode), the computer can temporarily modify the energy management strategy to adapt regenerative braking to the distance to the traffic light, and the computer can send an indication to the driver to release the accelerator pedal.

[0012] When the traffic light displays the first signal, and when the time until the signal changes is greater than the time to cover the distance to the traffic light at the vehicle's current speed, the computer may temporarily modify the energy management strategy so as to maintain the desired wheel speed, preferably in all-electric mode, and the computer may send an instruction to the driver to maintain at least the current vehicle speed.

[0013] When the traffic light displays the first signal, and when the time taken to cover the distance to the traffic light at the current speed of the vehicle is greater than the time taken to change the signal, which itself is greater than the time taken to cover the distance to the traffic light at the maximum authorized speed, the computer may temporarily modify the energy management strategy so as to start the thermal engine with the thermal engine stopped and keep it running until the traffic light is passed in order to provide additional power, and the computer may send an indication to the driver of the maximum authorized speed to be reached.

[0014] When the traffic light displays the first signal, and when the time to cover the distance to the traffic light at the maximum authorized speed is greater than the time for the signal to change, the computer can temporarily modify the energy management strategy to force a full electric operating mode for regenerative braking, and the computer can send an indication to the driver to release the accelerator pedal.

[0015] When the traffic light is displaying the second signal, and when the time until the signal changes is less than the time to cover the distance to the traffic light at the vehicle's current speed, the computer may maintain the energy management strategy unchanged, and the computer may send an instruction to the driver to maintain the speed of the vehicle unchanged so that the vehicle passes through the traffic light while displaying the first signal after changing from the second signal.

[0016] When the traffic light displays the second signal and the time required for the vehicle to cover the distance to the traffic light using engine braking is less than the time for the signal to change, the computer can modify the energy management strategy to force all-electric mode and accommodate regenerative braking, and the computer can send an indication to the driver of a recommended speed to release the accelerator pedal to minimize energy consumption when the vehicle reaches the traffic light while the traffic light displays the second signal before the signal changes.

[0017] When passing a traffic light, the computer can stop instructing the driver and the temporarily modified energy management strategy ends.

[0018] When there are several traffic lights on the route, the computer can temporarily modify the energy management strategy when passing the first traffic light to force the battery to discharge so that regenerative braking can still be performed when passing the next traffic light.

[0019] Another object of the invention is a control system for a motor vehicle equipped with a hybrid powertrain, a man-machine interface for displaying information to the driver, means for communicating with at least one traffic light and a control device configured to carry out the above-mentioned control process.

[0020] One advantage of the method and control system is that the energy consumption of a hybrid vehicle in an urban environment can be reduced when knowledge of traffic light changes is available. The powertrain management strategy can optimize energy consumption by knowing the actions to be taken in the near future and the associated power requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further objects, features and advantages of the present invention will become apparent from the following description, given by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0022] Figure 1 The main steps of the control process according to the present invention are shown. DETAILED DESCRIPTION

[0023] Traffic lights have two states. The first state corresponds to authorized passage. In most countries, this state corresponds to a green light. The second state corresponds to a mandatory stop. In most countries, this state corresponds to a red light.

[0024] The following symbols are defined.

[0025] Traffic light status

[0026] T cc The time when the signal changes

[0027] D The distance between traffic lights and vehicles

[0028] V ego Vehicle speed

[0029] V lim Use the maximum speed allowed on the road

[0030] T Vego =D / V ego The current speed of the vehicle V ego The time it takes to cover the distance D to the traffic light

[0031] At the maximum permissible speed V lim The time it takes to cover the distance D to the traffic light

[0032] T fm The time required for the vehicle to cover the distance D to the traffic light using engine braking.

[0033] T sailing The time required for the vehicle to cover the distance D to the traffic light in freewheeling mode (sailing mode).

[0034] Hybrid powertrain state changes are based on driver demand via the accelerator pedal, vehicle speed, and battery condition.

[0035] The process of controlling a hybrid motor vehicle equipped with a hybrid powertrain comprising a heat engine and at least one electric motor is performed by an on-board computer comprising a memory and a processor configured to execute the steps described below.

[0036] The hybrid powertrain has several operating modes.

[0037] In the first operating mode, only the electric motor generates torque at the wheels. The heat engine is not involved. In a hybrid vehicle, the heat engine is systematically switched off.

[0038] In the second operating mode, the thermal engine and the electric motor generate torque at the wheels in a manner known from the prior art, in particular according to the driver's request, the power each component can produce, the available fuel, the state of charge of the traction battery.

[0039] In hybrid mode, the electric motors can be driven to provide additional power to the wheels, or conversely, they can be used as generators to charge the battery.

[0040] In the third operating mode, only the thermal engine delivers torque to the wheels. This is particularly the case when the state of charge of the traction battery is too low to power the electric motor. A low battery state of charge can also be the result of on-board energy optimization.

[0041] Control process such as Figure 1 , and comprises a first step 1 of determining traffic light information. This information is acquired via a vehicle-to-infrastructure V2I (Vehicle-to-Infrastructure Communication) type of communication.

[0042] The state of a traffic light includes its current state (the color of the light) f and the remaining time T before the next change of the traffic light state cc The geographical location of a traffic light and the lanes it controls can also form part of the state of a traffic light. Given the location of a traffic light and the associated lane, it is possible to calculate the distance to a vehicle and whether the vehicle is affected by the lane it is using.

[0043] In the same first step 1, the information to be taken into account is determined according to the distance between the vehicle and each traffic light according to the planned path within a predetermined time frame T (for example 15 seconds).

[0044] In certain embodiments, possible paths are considered based on the direction of travel and signal plans surrounding the motor vehicle.

[0045] In a second step 2, an active signal displayed by a first traffic light on the path of the vehicle is determined.

[0046] When the traffic light shows the first signal, and until the signal changes, cc When the second signal is displayed in Then the process continues to the third step 3. Assuming that at the current speed V ego In this case, the vehicle will pass the traffic light while the first signal is displayed before changing to the second signal. The vehicle speed is then maintained. The energy management strategy is modified to maintain the required speed and power to the wheels. If all-electric operation meets this requirement, the thermal engine will not start.

[0047] Drivers were told to maintain speed.

[0048] When the light shows the first signal, and until the signal changes, the time T cc When the second signal is displayed in The process then continues with the fourth step 4. It is estimated that at the current speed, the vehicle will reach the traffic light while the second signal is displayed. On the other hand, by accelerating to the maximum authorized speed, the vehicle will pass the traffic light while the first signal is displayed before changing to the second signal.

[0049] The all-electric operating mode may not be efficient enough. In this case, the energy management strategy is modified to start the heat engine, thereby providing additional power. The energy management strategy is also modified to prevent the heat engine from stopping.

[0050] The driver is informed of the speed to be achieved.

[0051] When the traffic light shows the first signal, and during the signal change period T cc When the second signal is displayed in The process then continues with a fifth step 5. It is estimated that even at the highest authorized speed, the vehicle will reach the traffic light while the second signal is displayed.

[0052] The driver is then instructed to release the accelerator pedal. If the traction battery is not fully charged, the energy management strategy is modified to force full electric operating mode and regenerative braking is initiated.

[0053] When the traffic light shows the second signal, and until the signal changes, cc When the first signal is displayed, if The process then proceeds to step 6. It is assumed that at the current speed, after changing from the second signal, the vehicle will pass the traffic light when the first signal is displayed. The vehicle speed is then controlled to remain unchanged, and the energy management strategy is modified so that the operating mode of the powertrain remains unchanged. In particular, if sufficient power is provided, the operating mode may remain fully electric, otherwise the hybrid operating mode (second operating mode) is enabled.

[0054] Enabling hybrid mode: Start the hot engine, the mode remains unchanged (clutch, gearbox, etc. do not move), and the powertrain status remains unchanged.

[0055] When the traffic light shows the second signal, and until the signal changes, cc When the first signal is displayed, if The process then proceeds to the seventh step 7. It is estimated that at the current speed, the vehicle will reach the traffic light while the second signal is displayed before the signal changes. On the other hand, by switching to freewheel mode (sailing mode), the vehicle will pass the traffic light while the first signal is displayed after the signal changes.

[0056] The vehicle is controlled so that it runs in freewheel mode. In other words, if it were active, the injection would be cut off and the vehicle would move only under its own inertia, decelerating only by aerodynamic drag, tire drag and vehicle rolling resistance. The driver is instructed to release the accelerator pedal. When the hybrid vehicle is running in freewheel, the thermal engine is shut off and, if possible, the electric motor is disconnected to limit losses.

[0057] The energy management strategy is modified so that the all-electric operating mode is forced, shutting down the thermal engine. The energy management strategy is also modified to adapt regenerative braking to reach the set speed. Finally, when the traction battery is too discharged and the thermal engine shutdown phase is too short, the engine remains idling.

[0058] This is a hybrid mode where the electric motor is used in engine mode. If it is too short, stop / start of the heat engine is of no benefit.

[0059] When the traffic light displays the second signal, and during the signal change period T cc When the first signal is displayed, if T fm <T cc , the process proceeds to the eighth step 8. It is estimated that even in the engine braking mode, the vehicle will reach the traffic light while the second signal is displayed before the signal changes.

[0060] Give the driver the recommended speed and ask him to release the accelerator pedal.

[0061] The energy management strategy is modified to require the vehicle to operate in full electric mode in order to benefit from regenerative braking. The mechanical brakes are then used as a supplement.

[0062] At the end of steps 3 to 8, when passing a traffic light, the process is completed in a ninth step 9, during which the information displayed to the driver is blocked and all operating modes of the hybrid system are enabled. Then, considering the next traffic light, the process returns to step 1.

[0063] When there are several traffic lights, the energy management strategy can be modified when passing the first traffic light, forcing the battery to discharge so that regenerative braking can still be performed when passing the next traffic light.

Claims

1. A method for controlling a motor vehicle provided with a hybrid powertrain comprising a heat engine and at least one electric motor and controlled by a predetermined energy management strategy, the vehicle further comprising a computer, a human-machine interface for displaying information to the driver and means for communicating with at least one traffic light, the method comprising the following steps: - said computer receives information from traffic lights, - the computer determines the distance to the traffic light, the active signal displayed by the traffic light from a first signal related to an intersection permitted and a second signal related to an intersection prohibited, and the time until the traffic light makes a signal change based on the received information, - the computer compares the time until the traffic light makes a signal change with the time to traverse the distance to the traffic light, the computer temporarily modifies the energy management strategy as a function of the comparison result and sends to the driver an indication of at least one action to be performed consistent with the modification of the energy management strategy, so as to limit the energy consumed until the traffic light is crossed.

2. A method for controlling a motor vehicle according to claim 1, wherein: when the traffic light displays the second signal, and when the time to traverse the distance to the traffic light at the current speed of the vehicle is less than the time until the signal changes, which itself is less than the time required for the vehicle to travel the distance to the traffic light under free wheels, the computer temporarily changes the power management strategy to accommodate regenerative braking according to the distance to the traffic light, and The computer sends an instruction to the driver to release the accelerator pedal.

3. A method for controlling a motor vehicle according to any one of claims 1 to 2, wherein: When the traffic light displays the first signal, and when the time for the signal change is greater than the time to cross the distance to the traffic light at the current speed of the vehicle, the computer temporarily modifies the power management strategy so as to maintain the desired wheel speed, preferably in all-electric mode, and the computer sends an instruction to the driver to maintain at least the current vehicle speed.

4. A method for controlling a motor vehicle according to any one of claims 1 to 3, wherein: When the traffic light displays the first signal, and when the time to cover the distance to the traffic light at the current speed of the vehicle is greater than the time of the signal change, which itself is greater than the time to cover the distance to the traffic light at the maximum allowed speed, the computer temporarily changes the power management strategy so as to start the thermal engine with the thermal engine stopped and keep it running until the traffic light is crossed, in order to provide additional power, and the computer sends an indication to the driver of the maximum allowed speed to be reached.

5. A method for controlling a motor vehicle according to any one of claims 1 to 4, wherein: When the traffic light displays the first signal, and when the time to cover the distance to the traffic light at the maximum allowed speed is greater than the time until the signal changes, the computer temporarily changes the power management strategy to force a full electric operating mode under regenerative braking, and the computer sends an indication to the driver to release the accelerator pedal.

6. A method for controlling a motor vehicle according to any one of claims 1 to 5, wherein: When the traffic light displays the second signal, and when the time for the signal change is less than the time to cover the distance to the traffic light at the current speed of the vehicle, the computer does not change the power management strategy, and the computer sends an instruction to the driver to maintain the speed of the vehicle unchanged so that the vehicle passes through the traffic light while the vehicle will display the first signal after changing from the second signal.

7. A method for controlling a motor vehicle according to any one of claims 1 to 6, wherein: When the traffic light displays the second signal, and when the time required for the vehicle to travel the distance to the traffic light using engine braking is less than the time until the signal changes, the computer temporarily changes the power management strategy to force an all-electric mode and accommodate regenerative braking, and The computer sends an indication to the driver of a recommended speed to release the accelerator pedal to minimize energy consumption when the vehicle reaches the traffic light while the traffic light is displaying the second signal before the signal changes.

8. A method for controlling a motor vehicle according to any one of claims 1 to 7, wherein: When crossing the traffic light, the computer stops instructing the driver and the temporary modification of the energy management strategy ends.

9. A method for controlling a motor vehicle according to any one of claims 1 to 8, wherein: When a plurality of traffic lights are arranged on the crossing route, the computer temporarily modifies the energy management strategy to force the battery to discharge when passing the first traffic light, thereby maintaining the possibility of performing regenerative braking when passing the subsequent traffic lights.

10. A control system for a motor vehicle provided with a hybrid powertrain, a human-machine interface for displaying information to the driver, means for communicating with at least one traffic light and a control device configured to execute a control method as claimed in claims 1 to 9.

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