FR3104101A1 - hybrid type vehicle which has a selector for driving modes in difficult conditions and a navigation device - Google Patents

Abstract

The invention relates to a vehicle comprising a first thermal powertrain (10), a second electric powertrain (20), a set of computers, a first of said computers can only control the use of the first powertrain (10) or the combined use of said two powertrains (10, 20) and a selector allowing the driver to indicate difficult driving conditions to the first computer, said vehicle also comprising a navigation device, such that when the driver selects difficult driving conditions, said vehicle being on a road which includes an uphill section (40), the first calculator estimates, by means of a map provided by said navigation device, an estimate of the quantity of electrical energy necessary to climb said section (40 ) of the road with the combined use of the two powertrains (10, 20). Figure for the abstract: Fig.1

Description

vehicle of the hybrid type which comprises a selector of driving modes in difficult conditions and a navigation device

The present invention relates to a vehicle of the hybrid type with two powertrains and to a method for managing traction adapted to such a hybrid vehicle.

The present invention relates more particularly to a vehicle which comprises a first powertrain which comprises a heat engine and which rotates two first drive wheels of a first running gear, a second powertrain which comprises an electric motor powered by a battery and which rotates two second drive wheels of a second running gear, a set of computers of which a first of said computers can control only the use of the first powertrain or the combined use of said two powertrains and a selector allowing the driver to indicating difficult driving conditions to the first computer, said vehicle also comprising a navigation device.

The document WO2012127674 A1 relates to such a vehicle of the hybrid type which can be switched to a four-wheel drive mode combining the combustion engine with the electric motor.

But in the event of too great a drop in the battery when climbing a dirt road with low grip or any other difficult driving uphill, the vehicle may be deprived of the electric motor which risks blocking the vehicle in the slope because its entire strategy for climbing such a dirt road or any other difficult rolling climb relies on the use of four-wheel drive mode.

The device according to the invention overcomes this drawback. It comprises in fact according to a first characteristic a vehicle which comprises a first powertrain which comprises a heat engine and which rotates two first drive wheels of a first running gear, a second powertrain which comprises an electric motor powered by a battery and which rotates two second drive wheels of a second running gear, a set of computers of which a first of said computers can control only the use of the first powertrain or the combined use of said two powertrains and a selector allowing the driver to indicate to the first computer difficult driving conditions, the vehicle also comprising a navigation device, such that when the driver selects difficult driving conditions, the vehicle being on a road which includes an uphill section, the first computer estimates , by means of a cartography provided by the navigation device, an estimate of the amount of electrical energy required to climb the section of the road with the combined use of the two powertrains.

According to a second characteristic of the invention, the selector makes it possible to indicate that the road is covered with mud, is covered with sand or is snow-covered.

According to a third characteristic of the invention, the vehicle comprises a traction aid device which can only be activated when the first computer only controls the use of the first powertrain, the selector making it possible to control the driving modes of the device. help with motor skills.

According to a fourth characteristic of the invention, the vehicle comprising an inertial unit giving the inclination of the vehicle in its direction of travel and/or a camera adapted to film the road in front of the vehicle allowing the first computer to determine that the road presents an uphill section and to estimate the slope α of the uphill section by means of the cartography provided by the navigation device.

The present invention also relates to a method for managing the traction of such a vehicle, such that, depending on the initial charge of the battery and the estimation of the quantity of electrical energy required, the first computer favors either the first powertrain as long as the difficult driving conditions allow it or only the combined use of the two powertrains.

According to a first characteristic of the method according to the invention, for an initial charge of the battery which is greater than or equal to the sum of the estimate of the quantity of electrical energy required and of a reserve threshold, the first computer uses only the combination of the two powertrains to climb the section of road, the reserve threshold can be equal to 25% of the total battery charge.

According to a second characteristic of the method according to the invention, for an initial charge of the battery which is less than the sum of an estimate of the quantity of electrical energy required and of the reserve threshold and which is greater than or equal to the estimating the amount of electric power needed, the first computer uses only the first powertrain as long as the first computer determines a capability of the vehicle to climb the uphill section of the road only with the first powertrain, the capability of the vehicle to riding said section of road only with the first powertrain being determined by means of a first level of criteria.

According to a third characteristic of the method according to the invention, for an initial charge of the battery which is less than the estimate of the quantity of electrical energy required, the first computer uses only the first powertrain as long as the first computer determines a ability of the vehicle to climb the uphill section of the road only with the first powertrain, the ability of the vehicle to climb said section of the road only with the first powertrain being determined using a second level of criteria.

According to a fourth characteristic of the method according to the invention, the vehicle comprises a stability assistance device which calculates an adhesion coefficient µ, in the case where the selector indicates the presence of a road covered with mud or a road covered with snow, the first computer compares the value of the adhesion coefficient μ which must be less than a threshold adhesion coefficient to determine the inability of the vehicle to climb the section of the road only with the first power unit, the coefficient of threshold adherence which can be equal to 0.4, and for a slope α which is greater than 5% of inclination according to the first level of criteria and than 10% according to the second level of criteria, the first computer selects the use combination of the two powertrains.

According to a fifth characteristic of the method according to the invention, in the case where the selector indicates the presence of a road covered with sand, the first computer compares the forward speed of the vehicle which must be greater than a threshold forward speed to determine the inability of the vehicle to climb said section of the road only with the first powertrain, the threshold forward speed of the vehicle possibly being 3 km/h.

The accompanying drawings illustrate the invention:

represents a vehicle according to a first two-wheel drive control mode suitable for climbing a low-grip road.

represents a vehicle according to a second four-wheel-drive control mode suitable for driving up a low-grip road in the event that the use of only two-wheel drive is impossible.

represents a selector which allows the driver to indicate to a first computer of the vehicle difficult driving conditions for the first two-wheel-drive control mode or for the second four-wheel-drive control mode.

represents a logic diagram, according to the invention, determining the choice between the first two-wheel drive control mode and the second four-wheel drive control mode according to a first control strategy or according to a second control strategy.

represents a second flowchart, according to the invention, determining according to the first control strategy, the choice between the first two-wheel drive control mode and the second four-wheel drive control mode.

represents a third logic diagram, according to the invention, determining according to the second control strategy, determining the choice between the first two-wheel drive control mode and the second four-wheel drive control mode.

Referring to Figures 1 and 2, the vehicle 1 includes a first powertrain 10 which includes a heat engine and which rotates two first drive wheels 11 of a first running gear and a second powertrain 20 which includes an electric motor 30 and which rotates two second drive wheels 21 of a second running gear.

The propulsion battery 30 makes it possible to supply electricity to the electric motor of the second powertrain 20.

The vehicle 1 is represented as driving in an uphill section 40 of a road with low grip, possibly covered with mud, snow or sand and having a slope whose inclination α makes it difficult to find traction for the vehicle.

The vehicle comprises a set of computers (not shown) of which a first computer selectively controls either only the use of the first powertrain 10 according to FIG. combined use of the two powertrains 10 and 20, according to figure 2 with a first tractive force produced by the two first drive wheels 11 and a second tractive force 22 produced by the two second drive wheels 21.

Referring to Figure 3, the vehicle 1 includes a selector 50 which allows the driver to indicate to the first computer difficult driving conditions, in particular it allows to indicate that the road is covered with mud 51, is covered with sand 52 or is snowy 53.

The vehicle has a traction assistance device which uses a braking circuit and a stability control device better known as "ESP" (Electronic Stability Program), allowing the traction assistance device , in an application example, to brake one of the two first wheels 11 of the vehicle 1 and to cause the other first wheel 11 to slip voluntarily so as to dig into a muddy upper layer to regain grip on a drier lower layer .

The tractive force 13 applied to the first two wheels 11 can then vary greatly depending on the different grip search modes which depend in particular on the position of the selector 50.

Such a traction aid device also generally applies to a front axle of a vehicle which includes an electrically controlled steering box, so it is also possible to act directly on the steering angle of the first wheels 11 and this independently of the will of the driver, to seek grip.

Generally a second of the computers present on the vehicle is in charge of managing the traction aid device, but the same first computer can manage the whole thing.

Such a traction aid device can only be applied to a two-wheel drive vehicle and is not suitable for a four-wheel drive vehicle.

In the case of a combined use of the two powertrains 10 and 20, due to the presence of four-wheel drive, the management of motricity is done as simply as possible, without the use of a driving aid device. motor skills.

The traction force 12 applied by the first powertrain 10 to the front wheels 11 is then substantially equal to the traction force 22 applied by the second powertrain 20 to the rear wheels 21.

The front/rear distribution of the tractive force can vary in a known manner depending on the grip of each wheel.

Furthermore, a vehicle generally comprises detection means such as a windscreen camera, rotation sensors of the drive wheels to detect loss of grip and also a vehicle inclination sensor, generally an inertial unit, allowing determine whether the road is sloping and its inclination.

The first calculator retrieves information from the camera such as the presence of white lines which border a road laterally or the presence of stones and other roughness present on the road to determine whether it is a dirt road or an asphalt road.

The camera can also provide an estimate of the angle of inclination of the road ahead, this angle information will be correlated once the vehicle is on the slope by the inertial unit.

From the rotation sensors of the drive wheels, the first computer determines an adhesion coefficient µ, the value of this coefficient generally being between 0 and 1, the value close to 0 being for a totally icy road and the value close to 1 for a dry asphalt road.

The calculation of such a value of the adhesion coefficient µ is also used for the stability assistance device.

To ensure that such a slope can be climbed, the first computer seeks to save the energy of the battery 30 as much as possible and to do this the first computer favors the use of the first powertrain assembly 10 as long as the driving conditions seem to allow it.

The first computer calculates, by means of a map provided by said navigation device, an estimate of the amount of electrical energy necessary to climb the uphill section 40 of the road with the combined use of the two powertrains.

From this set of data, the first computer uses three flowcharts to scan all the possibilities that may arise when the vehicle has to approach such an uphill section 40 of the road with difficult driving conditions.

Referring to Figure 4, the first computer follows a first flowchart to estimate the control strategy to be adopted to cross a sector uphill 40 of a road with difficult driving conditions (low grip) and this depending on the initial battery charge 30.

In a first step 60, the first computer is waiting for information from the selector 50 to indicate to the first computer difficult driving conditions, in particular it makes it possible to indicate that the road is covered with mud 51, is covered with sand 52 or is snowy 53.

In a second step 70, if the initial charge of the battery 30 is at least greater than the estimate of the quantity of electrical energy necessary with in addition a reserve threshold, then the first computer controls the use of the combination of two power units 10 and 20 to climb the 40 section of the road.

An example of a value for the reserve threshold is 25% of the total charge of the battery 30 which makes it possible to have a sufficient energy reserve of the battery 30 at the top of the uphill section 40 to continue driving with the second mode of four-wheel drive 4WD when needed.

For an initial charge of the battery 30 which is less than the estimate of the quantity of electrical energy necessary with in addition the reserve threshold, the first computer goes to a third step 80, making it possible to discriminate a first level of criterion St1 and a second level of criterion St2 for managing the first two-wheel drive control mode and the second four-wheel drive control mode.

In step 80, if the initial charge of the battery 30 is greater than or equal to the estimate of the quantity of electrical energy required then the first computer uses a first level of criterion St1 as used in a second flowchart represented in Figure 5.

If the initial charge of the battery 30 is less than the estimate of the quantity of electrical energy required then the first computer uses a second level of criterion St2 as used in a third flowchart represented in figure 6.

Referring to Figure 5, the first computer follows a second flowchart corresponding to the choice of the first level of criterion St1 where the first computer recovers the positioning of the selector 50 according to three possibilities indicating that the road is covered with mud 51, is covered with sand 52 or is snow covered 53.

Stage 200 corresponds to the indication of a road covered in mud 51 activating the mud mode.

During a first step 210 of the mud mode, the first computer checks whether the value of the grip coefficient μ is lower or higher than 0.4.

If the value of the adhesion coefficient μ is less than 0.4 then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use only of the first powertrain 10 even aided by the motor aid device.

If the value of the grip coefficient μ is greater than 0.4 then the first computer goes to a second stage 220 of the mud mode and checks whether the value of the slope α of the uphill section 40 of the road is less or greater than 10 %.

If the value of the slope α of the uphill section 40 of the road is greater than 10%, then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the only use of the first powertrain 10, otherwise the first computer selects the first 2WD two-wheel drive control mode, estimating that the driving conditions seem to allow the use only of the first powertrain 10 aided by the traction.

Stage 300 corresponds to the indication of a road covered with sand 52 activating the sand mode.

The first computer then passes to a first step 310 of the sand mode by checking the speed of evolution of the vehicle.

If the value of the speed of movement of the vehicle is less than 3 km/h, then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use only of the first powertrain 10 even aided by the mobility aid device.

If the value of the speed of evolution of the vehicle is indeed greater than or equal to 3 km/h, the first computer estimates that the driving conditions seem to allow the use only of the first powertrain 10 aided by the assistance device for motor skills.

Step 400 corresponds to the indication of a road covered with snow 53 activating the snow mode.

The first computer then passes a first step 410 of the snow mode by checking whether the snow is groomed or powdery.

If the snow is not groomed then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use of only the first powertrain 10.

If the snow is groomed then the first computer goes to a second step 420 of the snow mode by checking whether the value of the slope α of the uphill section 40 of the road is less or more than 5%.

If the value of the slope α of the uphill section 40 of the road is greater than 5%, then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use only of the first powertrain 10 even aided by the traction aid device, otherwise the first computer selects the first 2WD two-wheel drive control mode, estimating that the driving conditions seem to allow the use of only the first group powertrain 10 aided by the mobility aid device.

Referring to Figure 6, the first computer follows a third flowchart corresponding to the choice of the second level of criterion St2 where the first computer recovers the positioning of the selector 50 according to three possibilities indicating that the road is covered with mud 51, is covered with sand 52 or is snow covered 53.

The steps of the second flowchart and of the third flowchart which are identical have the same reference.

Step 200 remains identical to the second flowchart and corresponds to the indication of a road covered with mud 51 activating the mud mode.

During a first stage 210 of the mud mode which remains identical to the second flowchart, the first computer checks whether the value of the grip coefficient μ is lower or higher than 0.4.

If the value of the adhesion coefficient µ is less than 0.4 then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use of only the first powertrain 10 even helped by the motor skills device.

If the value of the adhesion coefficient μ is greater than 0.4 then the first computer goes to a second stage 230 of the mud mode and checks whether the value of the slope α of the uphill section 40 of the road is lower or higher at 10%.

If the value of the slope α of the uphill section 40 of the road is greater than 10%, then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the only use of the first powertrain 10, otherwise the first computer selects the first 2WD two-wheel drive control mode, estimating that the driving conditions seem to allow the use only of the first powertrain 10 aided by the traction.

Step 300 remains identical to the second flowchart and corresponds to the indication of a road covered with sand 52 activating the sand mode.

The first computer then passes a first step 310 of the sand mode which remains identical to the second flowchart and which corresponds to checking the speed of evolution of the vehicle.

If the value of the speed of movement of the vehicle is less than 3 km/h, then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use only of the first powertrain 10 even aided by the mobility aid device.

If the value of the speed of evolution of the vehicle is indeed greater than or equal to 3 km/h, the first computer estimates that the driving conditions seem to allow the use only of the first powertrain 10 aided by the assistance device for motor skills.

Step 400 remains identical to the second flowchart and corresponds to the indication of a road covered with snow 53 activating the snow mode.

The first computer then goes through a first step 410 of the snow mode which remains identical to the second flowchart, by checking whether the snow is groomed or powdery.

If the snow is not groomed then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use of only the first powertrain 10.

If the snow is groomed then the first computer goes to a second step 430 of the snow mode by checking whether the value of the slope α of the uphill section 40 of the road is less or more than 10%.

If the value of the slope α of the uphill section 40 of the road is greater than 10%, then the first computer directly selects the second 4WD four-wheel drive control mode, estimating that the driving conditions do not seem to allow the use only of the first powertrain 10 even aided by the traction aid device, otherwise the first computer selects the first 2WD two-wheel drive control mode, estimating that the driving conditions seem to allow the use of only the first group powertrain aided by the traction aid device.

Switching between the 5% to 10% slope criterion saves battery 30 by further limiting the switch to 4WD four-wheel drive control mode involving the second powertrain 20.

Claims (10)

Vehicle comprising a first powertrain (10) which comprises a heat engine and which rotates two first drive wheels (11) of a first running gear, a second powertrain (20) which comprises an electric motor powered by a battery ( 30) and which rotates two second drive wheels (21) of a second running gear, a set of computers, a first of which can control only the use of the first powertrain (10) or the combined use of said two power units (10, 20) and a selector (50) allowing the driver to indicate difficult driving conditions to the first computer, said vehicle also comprising a navigation device, characterized in that when the driver selects difficult driving conditions (51, 52, 53), said vehicle being on a road which includes an uphill section (40), the first computer estimates, by means of a map provided by said navigation device, an estimate of the amount of energy electric required to climb said section (40) of the road with the combined use of the two powertrains (10, 20). Vehicle according to Claim 1, characterized in that the selector (50) makes it possible to indicate that the road is covered with mud (51), is covered with sand (52) or is snow-covered (53). Vehicle according to Claim 1 or 2, characterized in that the vehicle comprises a traction aid device which can only be activated when the first computer controls only the use of the first powertrain (10), the said selectors (50) allowing for controlling the driving modes of said mobility aid device. Vehicle according to any one of the preceding claims, characterized in that, the vehicle comprising an inertial unit giving the inclination of the vehicle in its direction of travel and/or a camera adapted to film the road presenting itself in front of the vehicle allowing the first computer to determine that the road has an uphill section (40) and to estimate the slope (α) of said uphill section (40) by means of the map provided by said navigation device. Method for managing the traction of a vehicle according to any one of the preceding claims, characterized in that, depending on the initial charge of the battery (30) and of the said estimate of the quantity of electrical energy required, the first computer favors either the first powertrain (10) as long as the difficult driving conditions allow it or only the combined use of the two powertrains (10, 20). Motor control method according to the preceding claim, characterized in that for an initial charge of the battery which is greater than or equal to the sum of the estimate of the quantity of electrical energy required and of a reserve threshold, the first computer uses only the combination of the two powertrains (10, 20) to climb said section (40) of road, said reserve threshold possibly being equal to 25% of the total charge of the battery (30). Method of managing motor skills according to Claim 6, characterized in that for an initial charge of the battery (30) which is less than the sum of an estimate of the quantity of electrical energy required and of the reserve threshold and which is greater than or equal to the estimate of the amount of electrical energy required, the first computer uses only the first powertrain (10) as long as the first computer determines a capacity of the vehicle to climb said section (40) of the road only with the first powertrain (10), the ability of the vehicle to climb said section (40) of the road only with the first powertrain (10) being determined by means of a first level of criteria (St1). Method of managing motor skills according to any one of Claims 5 to 7, characterized in that for an initial charge of the battery (30) which is less than the estimate of the quantity of electrical energy required, the first computer uses only the first powertrain (10) so long as the first computer determines a vehicle's ability to climb said section of road only with the first powertrain (10), the vehicle's ability to climb said section (40) of road only with the first powertrain (10) being determined by means of a second level of criteria (St2). Traction management method according to claim 8 taken in its dependence with claim 7, characterized in that the vehicle comprises a stability assistance device which calculates an adhesion coefficient µ, in the case where the selector indicates the presence of a road covered with mud (51) or a road covered with snow (53), the first computer compares the value of the adhesion coefficient µ which must be less than a threshold adhesion coefficient to determine the incapacity of the vehicle to climb said section (40) of the road only with the first powertrain (10), the threshold adhesion coefficient possibly being equal to 0.4, and for a slope (α) which is greater than 5% d tilt according to the first level of criteria (St1) and at 10% according to the second level of criterion (St2), the first computer selects the combined use of the two powertrains (10, 20). Method of managing traction according to any one of Claims 5 to 9, characterized in that, in the case where the selector (50) indicates the presence of a road covered with sand (52), the first computer compares the forward speed of the vehicle which must be greater than a threshold forward speed to determine the inability of the vehicle to climb said section (40) of the road with only the first powertrain (10), said forward speed vehicle threshold can be 3 km/h.