Method for controlling an electrical assembly of a motor vehicle having an internal combustion engine with hybridised manual transmission

Abstract

The invention relates to a method (1) for controlling an electrical assembly of a motor vehicle having an internal combustion engine with retroactively hybridised manual transmission, the method comprising • - a step (10) of detecting the acceleration or the deceleration of the motor vehicle; • - a step (13) of controlling a power setpoint (Precup) of a hybridisation electric machine capable of driving at least one wheel of the motor vehicle not driven by the internal combustion engine and suitable for producing a regenerative torque capable of generating an electric current intended to charge an associated electric battery, the control step being implemented according to the acceleration or the deceleration of the motor vehicle.

Description

Method for controlling an electrical assembly of a motor vehicle with an internal combustion engine and a hybridized manual gearbox

[0001] The invention relates to the field of hybridization of motor vehicles with internal combustion engines.

[0002] In particular, the invention relates to a method for controlling an electrical assembly of a motor vehicle with an internal combustion engine and a hybridized manual gearbox.

[0003] In the automotive field, it is well known that vehicles with internal combustion engines are intended to be gradually replaced by vehicles comprising electric motors or any other non-petroleum propulsion mode, or according to a hybrid operation combining an internal combustion engine and a non-thermal engine, in particular an electric machine.

[0004] The challenge is therefore to transform an internal combustion engine into a hybrid vehicle. This is known as hybridization of the motor vehicle. This solution makes it possible to make an existing internal combustion engine vehicle a plug-in hybrid so that it can drive entirely electric for a few dozen kilometers.

[0005] The most suitable thermal vehicles are so-called “segment B” vehicles, such as city vehicles, mostly with manual transmission.

[0006] In order to minimize the complexity and cost of the "retrofit" operation, in other words the hybridization of the existing vehicle, it is possible to add an electric motor to the rear axle, or 2 wheel motors, and a battery in the trunk, without touching the mechanical parts of the front axle.

[0007] In such a situation, the vehicle can operate:

[0008] - Either in pure electric with the rear axle only, which will be able to provide traction and regeneration when braking

[0009] - Either in pure thermal, with the electrified rear axle which will add additional friction, and will involve an increase in consumption, compared to the operation as it existed before its hybridization.

[0010] We will therefore avoid this last mode of operation in favor of a hybrid mode with charge maintenance, in other words in hybrid mode with two cases:

[0011] - The battery discharges and the electric motor contributes to traction with greatly reduced consumption

[0012] - The battery maintains its charge level, in which case only energy recovery during braking can compensate for the additional losses so as not to increase consumption (and potentially improve it a little)

[0013] However, such hybrid operation poses many problems regarding the management of energy recovery during braking, known as regenerative braking, due to the non-decoupling of the brake pedal, the structure of which is not modified during hybridization. Indeed, on a manual gearbox, the driver already manages deceleration through the engine brake on the front axle, depending on the gear ratio engaged.

[0014] For example, we know of document JP6354241 B2, which discloses a method for optimizing regenerative braking. However, this document does not solve the problem of regenerative braking for a vehicle that has been hybridized a posteriori, i.e. one to which an electric powertrain has been added after it has left the production line, and for which the brake pedal control is not decoupled.

[0015] There is therefore a need for a solution to optimize energy recovery during braking for a hybrid motor vehicle.

[0016] A first subject of the invention relates to a method for controlling an electrical assembly of a motor vehicle comprising an internal combustion engine, a manual gearbox and a clutch device actuated by the driver adapted to decouple or couple the manual gearbox to a shaft driven by the engine, said vehicle being hybridized with an electrical assembly comprising a battery of electric accumulators and an electric machine capable of driving at least one wheel of the motor vehicle which is not driven by the engine, said method comprising:

[0017] - A step of detecting the acceleration or deceleration of the motor vehicle;

[0018] - A step of controlling a power setpoint to the electric machine adapted to produce a regenerative torque capable of generating an electric current intended to recharge the electric storage battery, said setpoint being a function of the acceleration or deceleration of the motor vehicle.

[0019] This process makes it possible to optimize energy recovery during braking since energy recovery is activated at the time of deceleration, without it being necessary to modify the structure of the hybrid internal combustion vehicle.

[0020] Preferably, the step of controlling a power setpoint is implemented when the measured deceleration is greater than a predetermined deceleration threshold, said threshold being for example between -lm / s 2 and -2m / s 2 .

[0021] Advantageously and in a non-limiting manner, said power setpoint is adapted to converge the deceleration of the vehicle towards said predetermined deceleration threshold. Thus, it is possible to create the conditions for regenerative braking resembling the engine braking produced by conventional hybrid vehicles.

[0022] In one embodiment, the method may comprise:

[0023] - A step of acquiring an actuation signal from the clutch device, capable of providing at least one indication of decoupling of the shaft and the gearbox;

[0024] - A step of acquiring a signal for actuating the accelerator pedal of the motor vehicle, capable of providing at least one indication of release of the accelerator pedal;

[0025] said instruction being furthermore a function of the clutch device actuation signal and the accelerator pedal actuation signal.

[0026] These steps make it possible to take into account a change in vehicle speed to adapt the activation of energy recovery and thus make it possible to combine braking linked to the gear change and energy recovery without discomfort for passengers.

[0027] Preferably, the implementation of the control step is delayed by a predetermined delay value when the accelerator pedal actuation signal indicates a release of the accelerator pedal and when the clutch actuation signal indicates a decoupling of the shaft and the gearbox.

[0028] Preferably, said delay is between 1 second and 2 seconds.

[0029] Preferably, when the control of the electric machine is delayed, a profile of progressive increase of the torque control is calculated.

[0030] In another embodiment, the step of detecting the acceleration or deceleration involves the acquisition of a signal provided by an accelerometer sensor or the calculation of a derivative of a speed signal transmitted by a control unit of the motor vehicle.

[0031] A second subject of the invention is a Device for controlling an electrical assembly of a motor vehicle comprising an internal combustion engine, a manual gearbox and a clutch device actuated by the driver adapted to decouple or couple the manual gearbox to a shaft driven by the engine, said vehicle being hybridized with an electrical assembly comprising a battery of electric accumulators and an electrical machine capable of driving at least one wheel of the motor vehicle which is not driven by the engine, said device comprising:

[0032] - Means for detecting the acceleration or deceleration of the motor vehicle;

[0033] - A unit for controlling a power setpoint to the electric machine adapted to produce a regenerative torque capable of generating an electric current intended to recharge said electric storage battery, said power setpoint being a function of the acceleration or deceleration of the motor vehicle.

[0034] For the implementation of these latter means or the preceding automated means, the device will here comprise a computer, or more generally at least one processor or any other type of digital calculator, for example a calculator on board a vehicle. The device may also comprise a plurality of separate processors or digital calculators, forming different means of the device, cooperating with each other.

[0035] The invention also relates to a motor vehicle comprising an internal combustion engine, a manual gearbox and a clutch device actuated by the driver adapted to couple the manual gearbox to a drive shaft, said vehicle being hybridized with an electrical assembly comprising a battery of electric accumulators and an electrical machine capable of driving at least one wheel of the motor vehicle which is not driven by the engine, further comprising a control device as described above.

[0036] Other features and advantages of the invention will emerge from reading the description given below of a particular embodiment of the invention, given for informational purposes but not as a limitation, with reference to the drawings annexed on which:

[0037] [Fig. 1] represents a flowchart of the method according to the main embodiment of the invention;

[0038] [Fig. 2] represents a motor vehicle according to the invention; and

[0039] [Fig. 3] is a graph illustrating the behavior of the control process as a function of the operating parameters of the motor vehicle.

[0040] A motor vehicle 3 with an internal combustion engine 30 comprises in this embodiment a manual gearbox 31 and a clutch device 32 actuated by the driver, here by means of a clutch pedal adapted to couple (in the raised position, the driver not actuating the pedal) or decouple (in the depressed position, the driver actuating the pedal) the manual gearbox 31 from the drive shaft, not shown.

[0041] This vehicle 3 is hybridized a posteriori. In other words, an electrical assembly 34, 35 is added to this vehicle, comprising an electric machine 35 and an electric storage battery 34, to enable hybrid operation without modifying the specific structure of the vehicle 3, initially intended to operate with its internal combustion engine 30 only.

[0042] In this embodiment, the electric machine 35 is mounted in engagement on the rear tram, so that it is capable of rotating the axle and the wheels of the rear axle.

[0043] The invention is not limited to this particular method of coupling the electric machine to the wheel assembly of the motor vehicle. In particular, the invention can be adapted so that it comprises two electric machines, each associated with a wheel of the rear axle. This is then referred to as a wheel motor.

[0044] Furthermore, according to another alternative, when the internal combustion engine is mounted at the rear of the motor vehicle, the electric machine can then be installed at the front of the motor vehicle.

[0045] The electric machine 35 of the vehicle is adapted to produce a regenerative torque capable of generating an electric current intended to recharge the battery.

[0046] The operation of regenerative braking is well known. In order to recharge the battery 34, the machine can switch from a motor mode to a regenerative mode, in which it creates a resistive torque, this resistive torque being converted by the windings of the machine into an electric current which recharges the electric storage battery.

[0047] Since the structure is not modified during hybridization, the motor vehicle is not designed to manage energy recovery during braking. In particular, the brake pedal 33 is generally not decoupled from the powertrain.

[0048] In a conventional hybrid vehicle, the brake pedal is decoupled from the engine. In other words, the brake pedal does not directly act on the vehicle's brakes. In a hybrid vehicle, the brake command, such as the actuation of the brake pedal, is measured, and a computer determines whether regenerative braking can be initiated, via the effect of the electric machine, before activating the mechanical brakes when the braking request is greater. In other words, a braking signal is measured, for example a percentage of progression of the brake pedal travel, to calculate whether regenerative braking is possible or whether direct braking by mechanical braking means is necessary.

[0049] This solution is not possible in the context of our retrofitted hybrid vehicle.

[0050] Only regenerative braking could be directly controlled when the driver lifts off the accelerator. Furthermore, on a vehicle with a manual transmission, the driver already manages deceleration through engine braking on the front axle, depending on the gear ratio engaged.

[0051] In order to overcome this problem, a control method 1 of an electrical assembly 34, 35 is implemented for managing energy recovery during deceleration of the motor vehicle.

[0052] The method according to the invention comprises, first of all, a step 10 of detecting the acceleration or deceleration of the motor vehicle.

[0053] This step 10 is implemented in this embodiment by acquiring a measurement signal from an accelerometer sensor 37.

[0054] However, the invention is not limited to this particular embodiment. In particular, it is possible to implement the acceleration detection step 10 by calculating the derivative of a speed signal transmitted by a vehicle control member, or by any other suitable method.

[0055] Then, depending on the measured acceleration or deceleration, the method 1 comprises a step 13 of controlling a power setpoint P re cup to the electric machine 35 adapted to produce a regenerative torque capable of generating an electric current intended to recharge the battery 34.

[0056] This step is implemented by a control unit 36, for example here an on-board computer.

[0057] Control step 13 is notably implemented when the measured deceleration is greater than a predetermined threshold.

[0058] Preferably, the predetermined threshold is included in a range of values ​​from -lm / s 2 at -2m / s 2 , for example in this embodiment a deceleration threshold of -1.5m / s 2 .

[0059] As a deceleration corresponds to a negative acceleration, it is understood that a deceleration value "greater" than a deceleration threshold, for example a threshold of -1.5m / s 2 , is therefore a numerical value greater than the numerical value of the threshold, for example -1 2m / s 2 .

[0060] Deceleration -1.2m / s 2 is a deceleration value “greater” than the deceleration threshold of -1.5m / s 2 .

[0061] Also, when method 1 measures a deceleration greater than this threshold then the control unit is activated to trigger energy recovery.

[0062] In this context, process 1 will command 13 a power adapted to converge the total deceleration of the motor vehicle (natural deceleration and regenerative braking) towards the deceleration threshold, for example here -1.5m / s 2 .

[0063] However, the convergence value of the total deceleration may, alternatively, be different from the predetermined threshold. It may then be a second predetermined deceleration value.

[0064] On the contrary, if the deceleration is lower than this threshold, under the effect of the engine brake, in other words if the total acceleration is lower than -1.5m / s 2 , then the control unit 13 does not command regenerative braking to the electric machine 35.

[0065] It will be noted, as will be explained later in the example of Figure 2, in phase P3, that if the mechanical brake pedal is actuated, while the regenerative braking is already active, the total acceleration may be lower than the deceleration threshold without the regenerative braking being deactivated, because in this context, the driver's will takes precedence, and here his will is to increase the total deceleration of the vehicle.

[0066] Furthermore, according to a preferred embodiment of the invention, but in a non-limiting manner, upstream of the control step 13, a step 11 of acquiring an actuation signal from the clutch device, capable of providing at least one indication of disengagement.

[0067] This acquisition step 11 is implemented by a sensor which measures the travel of the clutch pedal belonging to the clutch device 32.

[0068] The invention is not limited to this clutch pedal travel sensor and any known means for acquiring information regarding the actuation of the clutch could be substituted for it.

[0069] For example, the driver is considered to have completely decoupled the gearbox from the drive shaft when the clutch pedal travel is between 40% and 60% of its travel, for example when the pedal travel is at 55% of its maximum travel.

[0070] The method 1 also comprises, upstream of the control step, a step 12 of acquiring a signal for actuating the accelerator pedal of the motor vehicle, capable of providing at least one indication of release of the accelerator pedal.

[0071] The control step 13 is then implemented as a function of the actuation signal of the clutch device 32 and the actuation signal of the accelerator pedal 33, in addition to the measured acceleration or deceleration.

[0072] Thus, when the accelerator pedal actuation signal indicates a release of the accelerator pedal and the clutch actuation signal indicates a disengagement, then the implementation of the control step is delayed by a predetermined delay value, because it is understood that this sequence of actions indicates a desire for a gear change initiated by the driver. However, in such a situation, the driver does not wish to experience unexpected behavior from the vehicle such as increased deceleration due to regenerative braking.

[0073] Preferably, the delay is between 1 second and 2 seconds.

[0074] Preferably, when the control of the electric machine is delayed, a profile of progressive increase in the torque control is then calculated, making it possible to activate the regenerative braking without disturbing the driver.

[0075] Alternatively, one can not delay the regenerative braking but only calculate a profile of progressive increase of the torque control, as illustrated in figure 2 in its PL phase

[0076] With this process 1, the downshift carried out by the driver will be completely smoothed by the regeneration of the rear axle, so as to have a feeling close to a very flexible automatic gearbox and this process can also be adapted to any manual gearbox despite the diversity of hybrid vehicles, with simply a recalibration of the threshold and the delay according to the engine braking levels of each car.

[0077] We now illustrate this process 1 with figure 2.

[0078] We notice in a first phase PI that the driver releases his accelerator pedal 25 at t=2, and simultaneously increases the ratio 24 of the passing gearbox from 3 to 4. 0 t=2, the vehicle experiences a slight deceleration 20, generated by the progressive increase of regenerative braking 21, which produces a significantly stronger general deceleration 20.

[0079] As soon as the accelerator pedal is reactivated, at t=3, and the gear is changed, we notice the immediate stopping of regenerative braking 21 and a positive resumption of the total acceleration 20 of the vehicle.

[0080] In a second phase P2 of example, we notice at t=6 a release of the accelerator pedal 25, causing a total deceleration 20 of the vehicle around -0.5m / s 2 .

[0081] At this point, process 1 then commands 13 regenerative braking. 21, according to a progressive curve, stabilizing the deceleration at the target value of -1.5m / s 2 , reached significantly at t=9.

[0082] However, near t=l 1 , we notice that the gear ratio 24 goes from 4 to 3, this is a downshift, causing engine braking 22 in addition to the total deceleration, and a total acceleration less than -1.5m / s 2 , the regenerative braking 21 is then immediately cancelled, and a new control slope is calculated in order to maintain this deceleration at -1.5m / s 2 .

[0083] When the mechanical brake 23, in phase P3 is activated, the regenerative braking 21 is however maintained, since the driver indicates a desire to increase the total deceleration 20 of the motor vehicle. It is noted that this behavior is consistent in order not to have an effect contrary to the driver's wishes, the release of the regenerative braking would in fact have the effect of reaccelerating at the moment when the driver activates the mechanical brake.

Claims

Claims

1. Method (1) for controlling an electrical assembly (34, 35) of a motor vehicle (3) comprising an internal combustion engine (30), a manual gearbox (31) and a clutch device (32) actuated by the driver adapted to decouple or couple the manual gearbox (31) to a shaft driven by the engine (30), said vehicle (3) being hybridized with an electrical assembly (34, 35) comprising an electric storage battery (34) and an electric machine (35) capable of driving at least one wheel of the motor vehicle which is not driven by the engine (30), said method (1) comprising: - A step of detecting (10) the acceleration or deceleration of the motor vehicle (3); - A control step (13) of a power setpoint (P recup) to the electric machine (35) adapted to produce a regenerative torque capable of generating an electric current intended to recharge the electric accumulator battery (34), said instruction being a function of the acceleration or deceleration of the motor vehicle (3).

2. Method (1) according to claim 1, characterized in that the step of controlling (13) a power setpoint is implemented when the measured deceleration is greater than a predetermined deceleration threshold, said threshold being for example between -lm / s 2 and -2m / s 2 .

3. Method (1) according to claim 2, characterized in that said power setpoint is adapted to cause the deceleration of the vehicle (3) to converge towards said predetermined deceleration threshold.

4. Method (1) according to any one of claims 1 to 3 characterized in that it comprises: - A step of acquiring (11) an actuation signal of the clutch device (32), capable of providing at least one indication of decoupling of the shaft and the gearbox (31); - A step of acquiring (12) a signal for actuating the accelerator pedal of the motor vehicle, capable of providing at least one indication of release of the accelerator pedal; said instruction furthermore being a function of the signal for actuating the clutch device (32) and of the signal for actuating the accelerator pedal.

5. Method (1) according to claim 4, characterized in that the implementation of the control step (13) is delayed by a predetermined delay value when the accelerator pedal actuation signal indicates a release of the accelerator pedal and when the clutch actuation signal (32) indicates a decoupling of the shaft and the gearbox (31).

6. Method (1) according to claim 5, characterized in that said delay is between 1 second and 2 seconds.

7. Method (1) according to claim 5 or 6, characterized in that when the control of the electric machine is delayed, a profile of progressive increase in the torque control is calculated.

8. Method (1) according to any one of the preceding claims, characterized in that the step of detecting (10) the acceleration or deceleration implements the acquisition of a signal provided by an accelerometer sensor (37) or the calculation of a derivative of a speed signal transmitted by a control member of the motor vehicle.

9. Device (36) for controlling an electrical assembly of a motor vehicle (3) comprising an internal combustion engine (30), a manual gearbox (31) and a clutch device (32) actuated by the driver adapted to decouple or couple the manual gearbox (31) to a shaft driven by the engine (30), said vehicle (3) being hybridized with an electrical assembly (34, 35) comprising an electric accumulator battery (34) and an electric machine (35) capable of driving at least one wheel of the motor vehicle which is not driven by the engine (30), said device comprising: - Means for detecting (37) the acceleration or deceleration of the motor vehicle; - A control unit (36) for supplying a power setpoint to the electric machine (35) adapted to produce a regenerative torque capable of generating an electric current intended to recharge said electric storage battery (34), said power setpoint being a function of the acceleration or deceleration of the motor vehicle (3).

10. Motor vehicle (3) comprising an internal combustion engine (30), a manual gearbox (31) and a clutch device (32) actuated by the driver adapted to couple the manual gearbox (31) to a drive shaft, said vehicle (3) being hybridized with an electrical assembly (34, 35) comprising an electric accumulator battery (34) and an electric machine (35) capable of driving at least one wheel of the motor vehicle which is not driven by the engine (30), characterized in that it further comprises a control device (36) according to claim 9.

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