METHOD FOR TAKEOFF OF A HYBRID VEHICLE

Abstract

One aspect of the invention relates to a method 100 for launching a hybrid vehicle comprising the steps of: When the vehicle is stationary and a driver requests a torque to move the vehicle, determining 101 a vehicle tilt value in the direction of travel and / or a load value for said vehicle; If the vehicle tilt value is greater than a positive threshold tilt value and / or if the load value is greater than a threshold load value, transmitting 102: A first torque value to a first wheel shaft by means of a first rotating electrical machine; A second torque value to said first wheel shaft by means of a heat engine; and A third torque value to a second wheel shaft by means of a second rotating electrical machine. Figure 2.

Description

Title of the invention: METHOD FOR TAKEOFF OF A HYBRID VEHICLE

[0001] One aspect of the invention relates to a method for launching a hybrid vehicle. Another aspect of the invention relates to a hybrid vehicle arranged to perform the steps of the method.

[0002] The invention aims to optimize vehicle acceleration when taking off on an uphill slope or when heavily loaded, while avoiding the risk of overheating the clutch located between the internal combustion engine and a wheel shaft of the vehicle.

[0003] The invention finds a particularly advantageous application in the field of hybrid motor vehicles. Such hybrid motor vehicles can be equipped with a 48V or 400V power battery.

[0004] In this text, the term "starting" is used to refer to the rotation of the crankshaft of the internal combustion engine. The term "take-off" is used to refer to the movement of the vehicle when it changes from a zero speed to a non-zero speed.

[0005] Hybrid vehicles combine the use of thermal energy and electrical energy to achieve their traction.

[0006] Such a type of hybrid vehicle is usually equipped with a combustion engine and an electric motor connected to a front axle of the vehicle. The combustion engine can be mechanically disconnected from the front axle of the vehicle by means of actuation of a clutch.

[0007] To guarantee the torque applied to the wheel shaft necessary for the advancement of the vehicle and the progressiveness of the advancement of the vehicle, the torque supplied by the internal combustion engine and its rotational speed are greater than the requirements of the wheel shaft and the progressiveness is achieved by the slippage of the clutch.

[0008] If the start is carried out when the vehicle is on an uphill slope or heavily loaded, for example by using a trailer, there is a risk of overheating of the clutch which is located between the internal combustion engine and the front wheel shaft.

[0009] In order to reduce clutch slippage, it is known from document DE-Al-102020134691 to combine the use of the internal combustion engine and the rotating electric machine when the vehicle is on a road with an uphill slope.

[0010] It sometimes happens that the torque transmitted by the rotating electrical machine is not sufficient, so that the torque transmitted by the internal combustion engine to the wheel shaft is increased. This increase generates slippage and therefore overheating of the clutch. This overheating contributes to premature wear of the clutch.

[0011] The object of the invention is to overcome the drawbacks of the prior art by proposing a method of taking off a hybrid vehicle to prevent the clutch from overheating when the vehicle is positioned on an uphill slope or when it is heavily loaded.

[0012] In this context, the invention, in its broadest sense, relates to a method for launching a hybrid vehicle. The method according to this aspect of the invention is remarkable in that it comprises the steps, executed by vehicle control means, of: • When the vehicle is stopped and a driver makes a request for vehicle displacement torque, determine a vehicle inclination value in the direction of travel of the vehicle and / or a load value of said vehicle; • If the vehicle's inclination value exceeds a positive threshold inclination value and / or if the load value exceeds a threshold load value, transmit: • A first torque value applied to a first wheel shaft of the vehicle by means of a first rotating electrical machine of the vehicle, • A second torque value at the first axle shaft by means of a vehicle's internal combustion engine, and • A third torque value to the second wheel shaft of the vehicle by means of a second rotating electrical machine of the vehicle.

[0013] Thanks to the method according to the invention, during vehicle takeoff on an uphill slope and / or when heavily loaded, the internal combustion engine is supported by a rotating front electric machine and a rotating rear electric machine. The torque supplied by the internal combustion engine is thus greatly reduced, so that clutch slippage is also greatly reduced, or even eliminated. The clutch life is therefore significantly improved.

[0014] In addition to the characteristics just mentioned in the preceding paragraph, the process according to this aspect of the invention may have one or more complementary characteristics from among the following, considered individually or according to all technically possible combinations.

[0015] According to a non-limiting aspect of the invention, when the vehicle speed exceeds a threshold vehicle speed, the method includes a step, executed by the control means, of stopping the torque transmission of the second machine rotating electric motor on the second wheel shaft.

[0016] According to a non-limiting aspect of the invention, the threshold vehicle speed is between 110 km / h and 150 km / h.

[0017] According to a non-limiting aspect of the invention, when an amount of energy stored in a vehicle power battery arranged to electrically power the first and second rotating electric machines is less than an energy threshold, the method includes a step, executed by the control means, of stopping the transmission of torque from the second rotating electric machine to the second wheel shaft.

[0018] According to a non-limiting aspect of the invention, the quantity of energy is formed by a state of charge of the power battery and the energy threshold is formed by a threshold state of charge of the power battery.

[0019] Another aspect of the invention relates to a hybrid vehicle comprising control means arranged to perform the steps of the process according to any one of the aforementioned aspects of the invention.

[0020] According to a non-limiting aspect of the invention, the vehicle includes a 48V or 400V type power battery.

[0021] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0022] [Fig-1] illustrates, schematically, a hybrid vehicle according to a non- limiting of the invention.

[0023] [Fig.2] shows, schematically, the steps of a process according to a non-limiting aspect of the invention.

[0024] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0025] [Fig.1] schematically illustrates a hybrid vehicle 1 conforming to a non-limiting implementation of the invention.

[0026] Without limitation, vehicle 1 hybrid may be formed by a 48V or 400V type hybrid vehicle.

[0027] Hybrid vehicle 1 comprises: • A 2-stroke internal combustion engine; • A clutch 3; • A first rotating electrical machine 4; • A 5-speed gearbox; • A first wheel shaft 6; • A second rotating electrical machine 7; • A reducer 8; • A second wheel shaft 9; • A 10V type 400V power battery; • Control measures 11; • Means of determining an inclination 12 of the vehicle 1 in the direction of forward movement of the vehicle; • Means of determining a load 13 of the hybrid vehicle 1; • An accelerator pedal 14; and • A sensor for measuring a displacement 15 of the accelerator pedal 14.

[0028] In this non-limiting embodiment example, the first wheel shaft 6 forms the front wheel assembly of the hybrid vehicle 1 and the second wheel shaft 9 forms the rear wheel assembly of the hybrid vehicle 1.

[0029] When the clutch 3 is closed, the internal combustion engine 2 is mechanically connected to the first wheel shaft 6 and is able to transmit a first value of torque to the first wheel shaft 6. Conversely, when the clutch 3 is open, the internal combustion engine 2 is mechanically disconnected from the first wheel shaft 6 and is thus unable to transmit any torque to the first wheel shaft 6.

[0030] Furthermore, when the first rotating electric machine 4 is electrically powered by the power battery 10, the first rotating electric machine 4 is able to transmit a second torque value to the first wheel shaft 6.

[0031] In other words, the heat engine 2 and the first rotating electric machine 4 can be operated simultaneously or independently of each other to transmit torque to the first wheel shaft 6.

[0032] The second rotating electric machine 7 is able to provide a third torque value to the second wheel shaft 9.

[0033] The control means 11 are arranged to execute the steps of the takeoff process of a hybrid vehicle 1 according to a non-limiting aspect of the invention illustrated in [Fig.2],

[0034] By way of non-limitation, the control means 11 may consist of: • A vehicle control unit (more commonly known by its acronym VCU), and / or • A motor control unit (more commonly known by the acronym MCU for Motor Control Unit in English),

[0035] Figure [Fig. 2] shows a step diagram of an implementation method of process 100 according to the invention.

[0036] The steps of the process 100 are executed by control means 11 of a hybrid vehicle 1 such as, for example, that illustrated in [Fig.1].

[0037] When the hybrid vehicle 1 is stopped and a driver makes a request for vehicle 1 hybrid displacement torque, the process 100 includes a step of determining 101 a value of inclination of vehicle 1 in the direction of forward movement of the vehicle and / or a value of load of said vehicle.

[0038] A stationary vehicle is defined as a started vehicle that is not moving. When the driver wishes to start their hybrid vehicle 1 (in other words, to get their hybrid vehicle moving), they press the accelerator pedal 14. The driver's request for torque can then be detected by the accelerator pedal displacement sensor 15. This request is then transmitted by the displacement sensor 15 to the control means 11.

[0039] In a first non-limiting implementation, when this demand for displacement torque is detected by the control means 11, the latter determine 101 a value of inclination of the vehicle 1 in the direction of advancement of the vehicle 1.

[0040] In a second, non-limiting, different embodiment, when this demand for displacement torque is detected by the control means 11, the latter determine 101 a load value of the vehicle 1.

[0041] In a third, non-limiting embodiment that is still different, when this demand for displacement torque is detected by the control means 11, the latter determine 101 a value of inclination of the vehicle 1 in the direction of advancement of the vehicle 1 and a value of load of the vehicle 1.

[0042] In the first implementation, if the determined inclination value is greater than a positive threshold inclination value, for example 8%, the method 100 includes a step of transmitting 102: • A first torque value at the first wheel shaft 6 of vehicle 1 by means of the first rotating electrical machine 4, • A second torque value at the first wheel shaft 6 by means of the internal combustion engine 2, and • A third torque value at the second wheel shaft 9 of vehicle 1 by means of the second rotating electrical machine 7.

[0043] The positive threshold inclination corresponds to an angle, 8% in our example, formed between a horizontal plane and the road on which the vehicle 1 is located.

[0044] The sum of the first, second and third torque values ​​corresponds to the vehicle displacement torque requested by the driver of vehicle 1 by means of the accelerator pedal 14. The first, second and third torque values ​​are determined in such a way as to reduce the risk of slippage of the clutch 3.

[0045] In the second implementation, if the determined load value is greater than a threshold load value, for example 2200 kg for a sedan, the method 100 includes a transmission step 102: • A first torque value at the first wheel shaft 6 of vehicle 1 by means of the first rotating electrical machine 4, • A second torque value at the first wheel shaft 6 by means of the internal combustion engine 2, and • A third torque value at the second wheel shaft 9 of vehicle 1 by means of the second rotating electrical machine 7.

[0046] The sum of the first, second and third torque values ​​corresponds to the vehicle displacement torque requested by the driver of vehicle 1 by means of the accelerator pedal 14. The first, second and third torque values ​​are determined in such a way as to reduce the risk of slippage of the clutch 3.

[0047] In the third implementation, if the determined inclination value is greater than a positive threshold inclination value and if the determined load value is greater than a threshold load value, the method 100 includes a transmission step 102: • A first torque value at the first wheel shaft 6 of vehicle 1 by means of the first rotating electrical machine 4, • A second torque value at the first wheel shaft 6 by means of the internal combustion engine 2, and • A third torque value at the second wheel shaft 9 of vehicle 1 by means of the second rotating electrical machine 7.

[0048] The sum of the first, second and third torque values ​​corresponds to the vehicle displacement torque requested by the driver of vehicle 1 by means of the accelerator pedal 14. The first, second and third torque values ​​are determined in such a way as to reduce the risk of slippage of the clutch 3.

[0049] In a non-limiting example of an embodiment, when the vehicle speed is greater than a threshold vehicle speed, the method 100 includes a step of stopping 103 the transmission of torque from the second rotating electrical machine 7 to the second wheel shaft 9.

[0050] This threshold vehicle speed can be between 110 km / h and 150 km / h, typically it is equal to 130 km / h.

[0051] In a non-limiting example of an embodiment, when an amount of energy stored in the power battery 10 is less than an energy threshold, the method 100 includes a step of stopping 104 the transmission of torque from the second rotating electric machine 7 to the second wheel shaft 9.

[0052] This quantity of energy can be formed by a state of charge also known by the acronym SoC (for State of Charge in English) of the power battery 10. The energy threshold is then formed by a state of charge threshold of the power battery 10.

[0053] The various aspects of the aforementioned invention offer numerous advantages. Among these, we can mention: • Reduce the risk of overheating of the clutch located between the internal combustion engine and the first axle of the vehicle; • Increase the lifespan of the clutch; and • To satisfy the driver's torque demand.

Claims

Claims

1. Method (100) for taking off a hybrid vehicle (1), said method (100) being characterized in that it comprises the steps, executed by control means (11) of said vehicle (1), of: • When said vehicle (1) is stopped and a driver makes a request for torque to move said vehicle (1), determining (101) a value of inclination of said vehicle (1) in the direction of advance of said vehicle (1) and / or a value of load of said vehicle (1);• If said inclination value of said vehicle (1) is greater than a positive threshold inclination value and / or if said load value is greater than a threshold load value, transmitting (102): • A first torque value to a first wheel shaft (6) of said vehicle (1) by means of a first rotating electrical machine (4) of said vehicle (1), • A second torque value to said first wheel shaft (6) by means of a heat engine (2) of said vehicle (1), and • A third torque value to a second wheel shaft (9) of said vehicle (1) by means of a second rotating electrical machine (7) of said vehicle (1).;

2. Method (100) according to the preceding claim, characterized in that when the speed of the vehicle (1) is greater than a threshold vehicle speed, the method (100) comprises a step, executed by the control means (11), of stopping (103) said transmission of torque from the second rotating electrical machine (7) to the second wheel shaft (9).

3. Method (100) according to the preceding claim, characterized in that the threshold vehicle speed is between 110 km / h and 150 km / h.

4. Method (100) according to any one of the preceding claims, characterized in that when a quantity of energy stored in a power battery (10) of said vehicle (1) arranged to electrically power the first and second electrical machines rotating (4, 7) is less than an energy threshold, the method (100) comprises a step, executed by the control means (11), of stopping (104) said transmission of torque from said second rotating electrical machine (7) to the second wheel shaft (9).

5. Method (100) according to the preceding claim, characterized in that the quantity of energy is formed by a state of charge of the power battery (10) and the energy threshold is formed by a state of charge threshold of said power battery (10).

6. Hybrid vehicle (1) characterized in that it comprises control means (11) arranged to execute the steps of the method (100) according to any one of the preceding claims.

7. Hybrid vehicle (1) according to the preceding claim, characterized in that it comprises a power battery (10) of the 48V or 400V type.

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