Control system and method for controlling a drive shaft

Abstract

A control system designed to control the powertrain of a motor vehicle so that it operates in a selected configuration from a variety of options. the control system is designed to receive an environmental indicator signal that shows the presence of traffic lights in front of the vehicle, the control system is designed to predict, based on the ambient display signal, whether it is necessary to bring the vehicle to a standstill or to brake to a relatively low speed at a given time, wherein the control system is designed so that, if it is predicted that the vehicle will need to come to a standstill or decelerate to a relatively low speed at a certain time, the powertrain is made to operate in a second configuration rather than a first configuration before a braking torque is requested from the braking system by a driver or an automatic control system, wherein the control system is designed to perform regenerative braking when a braking torque is required, wherein wheels connected to the drivetrain cause one or more electric machines coupled to the drivetrain to generate electrical current for storage in a charging storage device, wherein in the first configuration a first group of one or more wheels is arranged for propulsion by the drive train and in the second configuration the first group of one or more wheels and additionally a second group of one or more wheels are arranged for propulsion by the drive train.

Description

ADMISSION BY REFERENCE

[0001] The entire content of the concurrently pending British patent application GB1202427.9 (publication number GB2499252), the UK patents GB2325716, GB2308415, GB2341430, GB2382158, GB2492748, GB2492655 and GB2381597 as well as US2003 / 0200016 are expressly incorporated here by reference. TECHNICAL AREA

[0002] The present disclosure relates to a vehicle control system and a control method, and in particular, but not exclusively, to a control system and a method for controlling a vehicle powertrain or a powertrain component, such as a transmission. Aspects of the invention relate to a control element, a transmission, a powertrain, an engine / powertrain, a vehicle, and a method. STATE OF THE ART

[0003] As is well known, a motor vehicle can be equipped with all-wheel drive, in which driving power is supplied to each of the vehicle's two pairs of wheels. Each pair of wheels can be considered part of an axle assembly, with the vehicle having a front axle assembly and a rear axle assembly. The driving power is supplied to the wheels via a drivetrain.

[0004] Some known vehicles are arranged so that both axle assemblies are permanently supplied with drive power. Other vehicles are arranged so that either only one axle assembly or both axle assemblies can be supplied with drive power. A selector switch, operable by the driver, may be provided to allow the driver to choose between two-wheel (front or rear axle assembly) and four-wheel (dual axle assembly) operation.

[0005] Some powertrain systems require the vehicle to be stationary during the transition between two-wheel and four-wheel drive. Such systems can be referred to as static disconnect / reconnect systems.

[0006] GB 2 407 804 A discloses a dynamic powertrain reconnection arrangement in which the wheels of an axle assembly can be reconnected to the powertrain after the wheels of that axle assembly have become disconnected while the vehicle is in motion. Such a system can be referred to as a dynamic powertrain reconnection system. The system disclosed in GB 2 407 804 A uses coupling arrangements to enable dynamic reconnection of the powertrain.

[0007] In DE 10 2014 112 637 A1 a control system for a four-wheel drive vehicle is provided.

[0008] US 2007 / 0193808A1 discloses a system and method for controlling a powertrain in a vehicle which determines a series of vehicle states and compares them with predetermined states to determine whether a secondary axle of the vehicle should be automatically connected to or disconnected from the powertrain.

[0009] DE 10 2011 004 425 A1 concerns a method for estimating the status of a traffic light system. The method determines whether a vehicle is approaching a traffic light system.

[0010] WO 2015 / 032 827 A2 relates to a system for controlling the speed of a vehicle. DE 10 2014 114 076 A1 provides methods, systems and vehicles for determining an effective brake pedal position for a vehicle.

[0011] In some known dynamic drivetrain reconnection systems, the vehicle is automatically able to disconnect the drivetrain from two wheels when a prescribed condition is met, allowing the vehicle to operate in two-wheel drive mode. The system automatically reconnects the drivetrain to enable all-wheel drive operation when the prescribed condition is not met.

[0012] One objective of the embodiments of the present invention is to at least partially mitigate the disadvantages of known dynamic drivetrain systems. SUMMARY OF THE INVENTION

[0013] The aforementioned disadvantages are at least partially solved by a control system according to claim 1 or by a method according to claim 18.

[0014] Exemplary embodiments of the invention are to be understood with reference to the attached claims.

[0015] Aspects of the invention create a control system, a drive train, an engine / drive train, a motor vehicle, a method, a carrier medium, a computer program product, a computer-readable medium and a processor.

[0016] In one aspect of the invention for which protection is sought, a control system is provided which is designed to control a motor vehicle's powertrain to operate in a selected configuration from a multitude of configurations. the control system is configured to receive an environmental display signal that indicates an environment surrounding the vehicle, wherein the control system is designed to determine, based on the ambient display signal, whether it is necessary to brake the vehicle preventively before a braking torque is requested from a braking system of the vehicle, and the control system is designed so that, if it is determined that the vehicle needs to be braked preventively, the powertrain is made to operate in a second configuration, rather than a first configuration, wherein in the first configuration a first group of one or more wheels is arranged for propulsion by the drive train and in the second configuration the first group of one or more wheels and additionally a second group of one or more wheels are arranged for propulsion by the drive train.

[0017] This feature has the advantage that, in certain situations, the powertrain can induce the second group of one or more wheels to generate braking force, for example, when the ambient warning signal indicates a need for preventive braking. The control system can, for instance, induce the powertrain to provide powertrain braking, such as engine braking or braking by means of an electric motor coupled to the powertrain.

[0018] Optionally, the control system is designed to perform regenerative braking, whereby wheels connected to the drivetrain cause one or more electric machines coupled to the drivetrain to generate electrical current for storage in a charge storage device.

[0019] The charge storage device can be a battery or a capacitive storage device.

[0020] The vehicle may have a drivetrain arranged to drive two groups of two wheels each, the first configuration corresponding to a two-wheel drive mode and the second configuration to a four-wheel drive mode.

[0021] Optionally, the ambient light indicator signal shows the presence of traffic lights in front of the vehicle.

[0022] Optionally, the ambient light indicator signal displays the status of the traffic light.

[0023] Optionally, the ambient light indicator shows the traffic in front of the vehicle.

[0024] Optionally, the ambient light indicator displays at least one of the following: traffic density; traffic speed.

[0025] Optionally, the ambient light indicator signal displays a speed limit.

[0026] Optionally, the environmental display signal is received from a camera.

[0027] Optionally, the ambient display signal is received by a radar module that displays objects relative to the vehicle.

[0028] Optionally, the radar module displays at least one of the following: position of objects relative to the vehicle; speed of objects relative to the vehicle.

[0029] Optionally, the ambient display signal is received via a data connection to the vehicle.

[0030] Optionally, the control system is designed to use a combination of map data and the environment display signal to determine whether the vehicle needs to be braked.

[0031] Optionally, the control system is designed to determine whether the vehicle needs to be braked preventively based on at least one of the following components: a measure of the vehicle's longitudinal acceleration; a slope of the road surface; Gradient; a parameter that specifies a surface friction coefficient between one or more wheels and a road surface; a selected driving mode in which the vehicle is operated, the driving mode being selected from a variety of driving modes.

[0032] Optionally, the control system is further designed to determine the degree of regenerative braking.

[0033] Optionally, the control system is designed to calculate the level of regenerative braking required depending on one or more of the following parameters: (a) a signal indicating the probability that the vehicle will have to come to a complete stop or slow down to a relatively low speed at a certain time; (b) Longitudinal acceleration of the vehicle; (c) Slope of the road surface; (d) Coefficient of surface friction between the wheels of the vehicle and the road surface; (e) Operating mode in which the vehicle is located; (f) Engine / powertrain mode in which the vehicle is operated; (g) State of charge (SOC) of vehicle battery 1B; and (h) Vehicle speed.

[0034] The control system can include one or more electronic control elements.

[0035] It should be noted that the control element(s) described herein may comprise a control unit or a computing device with one or more electronic processors. The system may comprise a single control unit or electronic control element, or alternatively, different functions of the control element may be designed or housed in different control units or control elements. The term "control unit," as used herein, includes both a single control unit or control element and a plurality of control units or control elements that together provide the specified control functionality. A set of instructions could be provided which, when designed, cause the computing device to implement the control techniques described herein.The instruction set could be embedded in one or more electronic processors. Alternatively, the instruction set could be provided as software designed on the computing device. The control element could be implemented in software designed on one or more processors. One or more other control elements could be implemented in software designed on one or more processors, optionally the same one or more processors as the control element. Other arrangements could be useful in some embodiments.

[0036] In one aspect of the invention for which protection is sought, a method for controlling a motor vehicle powertrain is provided to operate in a selected configuration from a plurality of configurations, the method comprising: Receiving an environment indicator signal that displays an environment surrounding the vehicle; Determine, based on the ambient display signal, whether it is necessary to brake the vehicle preventively before a braking torque is requested from a braking system of the vehicle; and If it is determined that the vehicle needs to be braked preventively, the powertrain should be instructed to operate in a second configuration rather than a first configuration. wherein in the first configuration a first group of one or more wheels is arranged for propulsion by the drive train and in the second configuration the first group of one or more wheels and additionally a second group of one or more wheels are arranged for propulsion by the drive train.

[0037] In one aspect of the invention for which protection is sought, a drive train is provided in combination with a system according to a preceding aspect.

[0038] In one aspect of the invention for which protection is sought, a motor / drivetrain is provided which comprises a drivetrain and a system according to a preceding aspect.

[0039] In another aspect of the invention for which protection is sought, a motor vehicle is provided which comprises a powertrain and a system according to a preceding aspect.

[0040] In one aspect of the invention for which protection is sought, a motor vehicle is provided comprising: a body, a plurality of wheels, an engine / drivetrain for driving the wheels, wherein the engine / drivetrain comprises a drivetrain and a braking system for braking the wheels, and a system according to a preceding aspect.

[0041] In one aspect of the invention for which protection is sought, a carrier medium is provided which carries a computer-readable code for controlling a vehicle to carry out the method of another aspect.

[0042] In another aspect of the invention for which protection is sought, a computer program product is provided that is executable on a processor to implement the method of another aspect.

[0043] In one aspect of the invention for which protection is sought, a computer-readable medium is provided which is loaded with the computer program product of another aspect.

[0044] In another aspect of the invention for which protection is sought, a processor is provided which is arranged to implement the method of another aspect or the computer program product of another aspect.

[0045] In another aspect of the invention for which protection is sought, a carrier medium is provided which carries a computer-readable code for controlling a vehicle to carry out the method of another aspect.

[0046] In another aspect of the invention for which protection is sought, a computer program product is provided that is executable on a processor to implement the method of another aspect.

[0047] In another aspect of the invention for which protection is sought, a computer-readable medium is provided which is loaded with the computer program product of another aspect.

[0048] In one aspect of the invention for which protection is sought, a processor is provided which is arranged to implement the method of another aspect.

[0049] Preventive braking, achieved by forcing the powertrain to operate in the second configuration, can have the advantage that a friction wheel braking system may not be necessary or can be used to generate reduced braking intensity, thereby reducing wear. Furthermore, in vehicles with a powertrain designed for regenerative braking, this regenerative braking capability can be used to initiate vehicle braking and generate energy, such as electrical energy in the case of an electric regenerative braking system.

[0050] Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples, and alternatives presented in the preceding paragraphs, in the claims, and / or in the following description and drawings, and in particular their individual features, may be considered independently of one another or in any combination. This means that all embodiments and / or features of any embodiment may be combined in any way and / or arrangement, provided that these features are not incompatible.The applicant reserves the right to amend any originally filed patent claim or to file any new patent claim accordingly, including the right to amend any originally filed patent claim to depend on and / or incorporate any feature of any other claim, even if it has not previously been claimed in this manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Exemplary embodiments of the invention are described below with reference to the accompanying drawings. Fig. Figure 1 is a schematic representation of a vehicle according to an embodiment of the present invention; Fig. Figure 2 is a schematic representation of a control system according to an embodiment of the present invention; Fig. Figure 3 shows a method for controlling a vehicle; Fig. Figure 4 is a schematic representation of a scenario in which a vehicle can be used; Fig. Figure 5 is a schematic representation of a scenario in which a vehicle can be used; Fig. Figure 6 is a schematic representation of a scenario in which a vehicle can be used; Fig. Figure 7 is a schematic representation of a vehicle according to a further embodiment of the present invention; Fig. Figure 8 is a schematic representation (a) of a vehicle according to a further embodiment of the present invention and (b) of an enlarged view of part of the vehicle shown in (a); and Fig. Figure 9 is a schematic representation (a) of a vehicle according to an embodiment of the present invention and (b) of an enlarged view of part of the vehicle shown in (a). DETAILED DESCRIPTION

[0052] A powertrain 5 of a motor vehicle 1 according to an embodiment of the present invention is in Fig. Figure 1 is shown schematically. The drive train 5 is connected to two drive motors via a transmission 18. The two drive motors are a crankshaft-integrated motor generator (CIMG) 16 and an internal combustion engine 11. The internal combustion engine 11 is coupled to the CIMG 16 via a coupling device 17. The CIMG 16, in turn, is essentially permanently coupled to an input shaft of the transmission 18, although in some embodiments the CIMG 16 can be coupled to the transmission 18 via a coupling device. An output shaft of the transmission 18 is coupled to the drive train 5.

[0053] The drive train 5 comprises a pair of front wheels 12, 13, an additional part 10 and a pair of rear wheels 14, 15.

[0054] The drive train 5 is arranged so that it can optionally transmit the power supplied by the transmission 18 from the internal combustion engine 11 and / or CIMG 16 only to the front wheels 12, 13 (in the case of two-wheel drive) or simultaneously to the front wheels 12, 13 and the rear wheels 14, 15 (in the case of all-wheel drive).

[0055] Power is transmitted from the internal combustion engine 11 and / or CIMG 16 to the front wheels 12, 13 via a clutch 17, a gearbox 18 and a pair of front drive shafts 19.

[0056] Power is transmitted to the rear wheels 14, 15 via the auxiliary part 10 of the drive train 5. The auxiliary part 10 has a power transmission unit (PTU) 24 with a power transmission coupling (PTC) 22, which serves to connect a main drive shaft or driveshaft 23 of the auxiliary part 10 to the gearbox 18. The driveshaft 23 is in turn coupled to a rear drive unit (RDU) 30, which serves to couple the driveshaft 23 to the rear drive shafts 26.

[0057] The RDU 30 comprises a pair of couplings 27 with input parts driven by a spool shaft 30S. The spool shaft 30S is driven by a crown gear 30C, which in turn is driven by a bevel gear 30B, which is itself driven by the driveshaft 23. The couplings 27 enable the RDU 30 to connect the driveshaft 23 to the rear drive shafts 26 when four-wheel drive operation is required.

[0058] The drivetrain 5 has a control element 40 arranged to control the operation of the PTU 24 and the clutches 27. When an all-wheel drive operating mode is required, the control element 40 is arranged to close the PTC 22 and the clutches 27 of the RDU 30. Since the drivetrain 5 forms part of an engine / drivetrain that includes the engine 11 and the transmission 18, the control element 40, in some embodiments, can also control the engine 11 and, optionally, the transmission 18, and could be referred to as an engine / drivetrain control unit. In some embodiments, the control element 40 can be arranged to cause the engine 11 to develop a required torque and / or rotate at a required speed.

[0059] In the embodiment of the Fig. 1. The PTC 22 and the RDU clutches 27 include corresponding actuators that serve to close the PTC 22 and the respective clutches 27 at a selected speed from a variety of different speeds. This enables the transition from two-wheel drive to all-wheel drive mode at a corresponding variety of different speeds. It should be noted that in the case of a friction clutch, when the clutch is closed, the maximum torque that the clutch can transmit from one input to one output increases to a maximum transmission torque value associated with the fully closed state. In the case of a multi-plate wet clutch, the maximum torque that the clutch can transmit can be at least partially a response to pressure on the clutch plates.

[0060] For the purposes of these instructions, a drivetrain 5 is considered to be in all-wheel drive mode or configuration when the non-zero pressure exerted on the discs of one or both clutches 27 exceeds a predetermined value that is higher than the value when the drivetrain 5 is in two-wheel drive mode or configuration. The predetermined value can be defined as a value that allows the transmission of torque through a clutch 27 up to a predetermined non-zero value.

[0061] It should be noted that the speed at which the respective actuators actuate the respective clutch arrangements can affect wear of the clutches and potentially one or more other components of the powertrain. 5. The actuation speed can also affect the NVH (noise, vibration and harshness) level experienced by a driver or occupant of a vehicle.

[0062] The present inventors have recognized that under certain circumstances it is desirable to actuate the clutches 27 of the RDU 30 and / or the PTC 22 at a reduced speed in order to reduce the speed at which the rear wheels 14, 15 and / or the gearbox are connected to the driveshaft 23. This can slow down the wear progression of the drivetrain components 5 and reduce the NVH conditions associated with the transition from the first to the second mode.

[0063] The control element 40 of the drive train 5 is arranged such that the additional drive train 10 is controlled such that slower actuation speeds of the PTC 22 and the clutches 27 are applied when a requirement to assume the all-wheel drive operating mode of the drive train 5 is less urgent, and higher actuation speeds are used when the requirement to assume all-wheel drive is more urgent.

[0064] Vehicle 1 is equipped with an anti-lock braking system (ABS) module 50, which is configured to control the brakes of one or more of the vehicle's wheels so that, when necessary, braking power is reduced to prevent skidding. Vehicle 1 also has a dynamic stability control (DSC) system 60, which is configured to control the torque delivered to one or more of the vehicle's wheels to prevent wheel spin.

[0065] In addition, vehicle 1 has a traction control system (TCS) 70, which is arranged to control the wheels of vehicle 1 and to apply a brake to any wheel when it is detected that the wheel is rotating at a speed higher than required to substantially prevent wheel slippage.

[0066] The vehicle has a Vehicle Control Unit (VCU) 1C designed for a range of vehicle control functions. The VCU 1C receives input signals from several vehicle sensors. These sensors (not shown) include sensors that provide continuous sensor outputs to the VCU 1C, such as wheel speed sensors, an ambient temperature sensor, an air pressure sensor, tire pressure sensors, the vehicle's yaw, roll, and pitch sensors, a vehicle speed sensor, a longitudinal acceleration sensor, an engine torque sensor (or engine torque estimator), a steering angle sensor, a steering wheel speed sensor, a gradient sensor (or gradient estimator), a lateral acceleration sensor (part of a stability control system (SCS)), a brake pedal position sensor, an accelerator pedal position sensor, and longitudinal, lateral, and vertical motion sensors. Additional inputs to the VCU 1C are listed in Fig. 2 shown.

[0067] In some other embodiments, only a selection of the sensors mentioned above may be used.

[0068] Vehicle 1 is also equipped with a variety of sensors that transmit separate sensor outputs to VCU 1C, including a transfer case or PTU status signal (indicating whether a PTU 24 gear ratio is set to an Hl range or an LO range), a TCS signal, and a DSC signal. It should be noted that the TCS and DSC signals each indicate whether the TCS or DSC systems 70 and 60 are currently intervening to control the application of braking torque and / or drivetrain torque to one or more wheels to improve vehicle stability as needed.

[0069] Vehicle 1 has a camera module 85 with a forward-facing video camera 85C designed to provide live video transmission to the VCU 1C. In some embodiments, one or more rear-facing cameras may be provided. Vehicle 1 also has three forward radar transceiver modules 87F and three rear radar transceiver modules 87R. The forward and rear modules 87F and 87R are designed to transmit radar waves and detect the transmitted waves reflected by objects in front of and behind the vehicle, respectively. The signals generated by the modules 87F and 87R are fed into a radar control module 87C via the vehicle's CAN bus (Controller Area Network) 1CAN. The radar control module 87C is designed to process the received signals and output to the VCU 1C, indicating the distance of the detected objects from the vehicle and their relative direction from the vehicle 1.It should be noted that in some embodiments different numbers of forward-facing and / or rear-facing radar modules 87F, 87R may be used. In some embodiments, only one or more forward-facing modules 87F or one or more rear-facing modules 87R may be provided.

[0070] Vehicle 1 also includes a radio module 83, designed to receive a live traffic data signal from a traffic data service and a live weather data signal from a weather data service. Module 83 processes the data and outputs it to the VCU 1C. Additionally, a positioning system in the form of a Global Positioning System (GPS) module 84 is provided, designed to determine the geographical location of Vehicle 1 using GPS satellite signals. In some embodiments, an alternative system for determining the vehicle's location may be used, e.g., a GPRS (General Packet Radio Service) module. The VCU 1C is equipped with a navigation assistance function.The VCU 1C is designed so that a user can enter an intended destination for vehicle 1, whereupon the VCU 1C calculates an optimal route to the intended destination and provides navigation instructions to the user so that the user can follow the optimal route.

[0071] The vehicle 1 comprises five subsystems which can be caused by the VCU 1C to operate in one of a multitude of different subsystem configuration modes to provide different vehicle performance characteristics, so that the vehicle can be operated in a predetermined of a multitude of different driving modes. The VCU 1C thus causes each of the multitude of vehicle subsystems 81a-d, 50 to operate in the subsystem configuration mode corresponding to the selected driving mode. In the present embodiment, the subsystems 81a-d, 50 are an engine management system 81a, a transmission control system 81b, an electronic power steering system 81c (ePAS unit), an ABS module 50, and a chassis control system 81d.

[0072] In the present embodiment, the VCU 1C is configured to operate the subsystems according to the driving mode, which is either manually selected by a user by means of a selector switch provided in a switch package 67 accessible to the driver while driving, or automatically by the VCU 1C, at least partially, in response to signals from various sensors on the vehicle 1. In automatic driving mode selection mode, the VCU 1C selects the driving mode according to the type of terrain in which the vehicle 1 is operated, as determined, at least partially, by reference to the signals received from the sensors, as described in the aforementioned UK patent GB2492655.

[0073] The driving modes include a Grass / Gravel / Snow driving mode (GKS mode), which is useful when the vehicle is driving on grass, gravel, or snow; a Mud / Furrow driving mode (SF mode), which is useful when the vehicle is driving on muddy or rutted terrain; a Rock Crawl / Scale mode (SG mode), which is useful when the vehicle is driving on stony or rocky terrain; a Sand mode, which is useful when the vehicle is driving on sandy terrain (or in deep, soft snow); and a Special Program Off mode (SP-OFF mode), which is a suitable compromise or general-purpose mode for all terrain conditions and especially for driving on highways and normal roads. The SP-OFF mode may also be referred to as the "Road" or "Highway" driving mode. Many other driving modes are also provided.

[0074] The different types of subsurface / terrain are classified according to the friction and roughness of the ground. For example, it makes sense to group grass, gravel, and snow together as subsurfaces that offer a low-friction, smooth surface, and equally useful to group rocky and scree-covered terrain as subsurfaces with high friction and a very high degree of roughness.

[0075] The way in which the VCU 1C is designed to allow the subsystems 81a-d, 50 to operate in different driving modes is described in more detail in the above-mentioned UK patent GB2492655.

[0076] Although five subsystems 81a-d, 50 are depicted as being controlled by the VCU 1C, in practice a larger number of vehicle subsystems 81a-d, 50 may be present in vehicle 1 and controlled by the VCU 1C. The VCU 1C includes a subsystem control module that sends control signals to each of the vehicle subsystems 81a-d, 50 so that each subsystem 81a-d, 50 operates in the subsystem configuration mode corresponding to the selected driving mode. Thus, each subsystem 81a-d, 50 can be made to operate in a manner that corresponds to the driving conditions, such as the terrain or road surface on which vehicle 1 is traveling (referred to as the terrain condition). The subsystems 81a-d, 50 also communicate with the subsystem control module of the VCU 1C to report back information about the subsystem status.It should be noted that in the present embodiment, the control element 40 can be used to control the powertrain 5 so that it assumes all-wheel drive mode depending on the driving mode in which the VCU 1C operates the vehicle 1. In the present embodiment, the control element 40 causes the powertrain 5 to operate in all-wheel drive mode when the VCU 1C is operating in a driving mode other than highway driving mode. When the VCU 1C is operating in highway driving mode, the VCU 1C causes the control element 40 to cause the powertrain to operate in two-wheel drive or all-wheel drive mode according to an active powertrain control strategy.

[0077] In the present embodiment, when operating in highway mode, the control element 40 is arranged such that it causes the drivetrain 5 to operate in two-wheel drive mode at speeds above a predetermined upper limit speed for all-wheel drive, v_U4WD. If the drivetrain 5 is in all-wheel drive mode and the speed exceeds the value v_U4WD, the control element 40 switches the drivetrain 5 to two-wheel drive mode. This function has the advantage that the vehicle 1 typically consumes less fuel and also emits fewer undesirable combustion products than would be the case in continuous all-wheel drive mode above v_U4WD. In the present embodiment, the value of v_U4WD is set to 35 km / h, although in some embodiments other values ​​such as 30 km / h, 40 km / h, or other values ​​may also be suitable.

[0078] If the drivetrain 5 is in two-wheel drive mode and the vehicle speed falls below a predetermined lower limit speed for all-wheel drive v_L4WD, the control element 40 causes the drivetrain 5 to switch from two-wheel drive mode to all-wheel drive mode. In the present embodiment, v_L4WD is set to a value of 12 km / h, although other values ​​may be suitable in some embodiments, such as 10 km / h, 15 km / h, 20 km / h, 25 km / h, or any other suitable value. It should be noted that, due to the relationship v_L4WD < v_U4WD, there is hysteresis with respect to the speeds at which the transitions between the two-wheel and four-wheel drive modes occur.This feature has the advantage of reducing the risk of mode flutter that could otherwise occur if v_L4WD were essentially equal to v_U4WD and the vehicle speed oscillated between speeds above and below v_L4WD in relatively rapid succession.

[0079] In the present embodiment, the engine management system 81a is designed to control the transmission of drive torque to the powertrain 5 via the motor 11 and the CIMG 16 according to an engine / powertrain control strategy aimed at reducing the vehicle's carbon dioxide emissions during a specific driving cycle. The engine management system 81a can be configured to cause the CIMG 16 to function as an electric motor, transmitting positive torque to the powertrain 5, or as a generator, transmitting negative torque to the powertrain 5, and additionally to switch the motor 11 on and off under the control of the VCU 1C. The VCU 1C determines whether the CIMG 16 operates as a motor or generator (or neither) and whether the motor 11 remains switched on or off according to the powertrain control strategy.

[0080] Vehicle 1 has a battery module 1B, which includes an inverter electrically connected to the CIMG 16 to power the CIMG 16 as a motor when needed and to receive the charge generated by the CIMG 16 when operating as a generator. As part of the motor / powertrain control strategy, the VCU 1 determines which of the following motor / powertrain modes the vehicle should operate in at any given time: (a) a parallel boost hybrid mode in which the CIMG 16 and the motor 11 provide a positive drive torque to the powertrain 5 essentially simultaneously in response to the torque demand of the engine / powertrain; (b) a parallel charging hybrid mode in which the CIMG 16 is driven as a generator while the motor 11 provides a positive drive torque to the powertrain 5 in response to the torque requirement of the motor / powertrain, and the battery module 1B can be charged by the CIMG 16; (c) an electric vehicle mode (EV mode) in which the motor 11 is switched off and the CIMG 16 alone supplies a positive drive torque to the powertrain 5 in response to the torque demand of the motor / powertrain; and (d) a hybrid locking mode in which the CIMG 16 is operated neither as an electric motor nor as a generator, with the motor 11 remaining switched on during a given driving cycle to provide positive drive torque when required.

[0081] The control unit VCU 1C is designed to determine when the powertrain 5 operates in a second configuration (e.g., 4WD) rather than a first configuration (e.g., 2WD). The control unit VCU 1C can preemptively brake the vehicle before a braking torque is requested from the braking system by switching the powertrain 5 to the all-wheel-drive configuration. The control unit VCU 1C can preemptively brake the vehicle before a driver requests a braking torque from the braking system (e.g., by pressing the brake pedal). Additionally or alternatively, the control unit VCU 1C can preemptively brake the vehicle before an automatic control system (e.g., cruise control or active speed control) requests a braking torque from the braking system. The control unit VCU 1C can determine whether it is necessary to preemptively brake the vehicle based on one or more environmental inputs.If it is determined that the vehicle needs to brake preventively, the VCU 1C control unit can cause the powertrain to operate in a second configuration (e.g., 4WD configuration) instead of a first configuration (e.g., 2WD configuration). The VCU 1C control unit can determine, from one or more environmental signals, the probability that the vehicle will need to come to a complete stop or decelerate to a relatively low speed at a specific time.

[0082] The VCU 1C control unit can receive a brake signal. This brake signal can indicate the activation of the vehicle's braking system. The brake signal can also indicate the amount of braking torque required from the braking system. The VCU 1C control unit can determine whether it is necessary to apply the brakes preventively if the brake signal indicates that the braking system has not been activated, or if no braking torque is required from the braking system.

[0083] Fig. Figure 2 shows the control unit VCU 1C and a group of modules 83, 85, and 87 that can output environmental signals to the control unit VCU 1C. One or more of the modules 83, 85, and 87 may be present. The control unit VCU 1C uses one or more of the environmental signals to determine whether the vehicle needs to be braked preventively by switching the powertrain to the 4WD configuration. The control unit VCU 1C outputs a powertrain change signal 95 to control the change in the powertrain configuration. For example, signal 95 can be output to control element 40, as shown in Fig. 1 shown.

[0084] A radar module 87 emits a signal indicating the environment around the vehicle. For example, a forward-facing radar module 87F emits a signal indicating the environment in front of the vehicle, and a rear-facing radar module 87R emits a signal indicating the environment behind the vehicle. A radar processing module 87P processes data generated by the one or more radar modules 87 and produces data indicating the position and speed of target objects relative to the vehicle 1, as determined by the radar modules 87. A target object can be another vehicle. Alternatively, the radar processing 87P can be performed by the control unit VCU 1C itself.

[0085] A camera 85C in camera module 85 generates a stream of video image data. An image processing module 85P processes the images to identify the presence of target objects in front of vehicle 1. Target objects can be one or more of the following: other vehicles; a feature of another vehicle (e.g., a brake light or turn signal); traffic signals (e.g., traffic lights); traffic signs (e.g., signs indicating a speed limit or a need to reduce speed). The image processing module 85P can use image recognition techniques to identify features that may indicate a need to brake the vehicle. The image processing module 85P extracts environmental data that is useful to the control unit VCU 1C. For example, the image processing module can determine that there are traffic signals in front of the vehicle that are currently red or changing to red.The image processing of the video image data stream captured by camera 85C can determine whether vehicle 1 is approaching stationary or slow-moving traffic. The image processing can determine whether brake lights of vehicles ahead of vehicle 1 are illuminated, indicating that traffic may be stationary, moving slowly, or slowing down. Each of the above examples illustrates environmental signals that may necessitate preventive braking of vehicle 1. Alternatively, the image processing 85P can be performed by the control unit VCU 1C itself.

[0086] The control unit VCU 1C can use a combination of data generated by the radar module 87 in conjunction with the camera 85.

[0087] In some embodiments, the control unit VCU 1C can determine an environmental signal based on the vehicle's current position or route, in combination with local data storage and / or external data. For example, a positioning function 84 (e.g., GPS) displays the current position of the vehicle 1. A navigation function 94 of the VCU 1C can determine a route for the vehicle using stored map data 92 and the positioning function 84. The navigation function 94 can use route data 93 (which, for example, specifies a destination or waypoints along the route). The map data 92 can indicate the presence of road features that may require the vehicle 1 to brake preventively. For example, the map data 92 can show intersections and / or traffic signals ahead of the vehicle.

[0088] The control unit VCU 1C can correlate the map data 92 with the traffic and traffic sign information acquired by the camera module 85 and the radar modules 87 to more reliably determine the probability that the vehicle 1 will come to a standstill or slow down relatively. For example, it should be noted that in some embodiments, the map data 92 can enable the VCU 1C to determine whether the traffic detected by the camera module 85 or the radar modules 87 in front of the vehicle 1 is in a path of the vehicle and, optionally, a predicted route of the vehicle, based on road layout data, for example, based on navigation guidance information generated in response to vehicle destination data. Likewise, the map data can be helpful in determining whether a traffic signal detected by the camera module 85 must be obeyed by the vehicle 1.This can be particularly useful at relatively complex intersections, where traffic signals controlling traffic flowing on different routes are detected in images generated by camera module 85.

[0089] In some embodiments, the VCU 1C can additionally or instead receive traffic light sequence information from a database 91 that forms part of the VCU 1 or is located outside the vehicle, e.g., via a wireless communication link, such as via the radio module 83. The sequence information 91 can be used by the VCU 1C to determine the status of a traffic light ahead of the vehicle 1, e.g., whether the signal indicates that a vehicle may proceed past a control point controlled by the traffic light or whether the vehicle must stop at the control point. In some embodiments, the VCU 1C can predict, based on the distance of the vehicle 1 from the traffic control point and optionally based on information about the traffic ahead of the vehicle 1, whether the vehicle 1 is likely to come to a complete stop or slow down to a relatively low speed.

[0090] It should be noted that the VCU 1C can also take into account traffic information received by the radio module 83 via a wireless traffic information data connection, such as an internet-based traffic information data connection, a traffic information channel (TMC), or another suitable traffic information source. This traffic information can include details about traffic density and speed at a specific geographic location. The VCU 1C can be configured to increase the likelihood that the vehicle will need to brake preventively at higher traffic density levels.

[0091] Fig. Figure 3 shows a procedure that can be implemented, for example, by the VCU 1C control unit. In block 401, one or more environmental signals are received. In block 402, the procedure uses these signals to determine whether the vehicle needs to be decelerated preventively before the braking system is required to apply a braking torque. If block 402 determines that the vehicle needs to be decelerated preventively, the procedure continues with block 403 and causes the drivetrain to operate in a second configuration (e.g., 4WD) rather than a first configuration (e.g., 2WD). If block 402 determines that there is no need to decelerate the vehicle prematurely, the procedure continues with block 404 and remains in the first configuration (e.g., 2WD). The procedure can be repeated by returning to block 401.

[0092] In Fig. Figures 4 to 6 are examples of scenarios in which environmental signals detected by the vehicle may indicate a need to brake the vehicle preventively.

[0093] Fig. Figure 4 shows a vehicle 1 on a road. A camera module 85 on the vehicle 1 captures an image or a series of images of the road in front of the vehicle 1. A traffic light 410 is located in front of the vehicle 1. The traffic light 410 is red. The image processing of the captured image(s) can recognize that the traffic light is red. Information from the navigation system and / or map data can confirm that the traffic light 410 is on the route of the vehicle 1. In other words, this confirms that the traffic light signal must be obeyed. The vehicle 1 uses the signal from the camera module 85 and optionally the map and / or route data to determine whether preventive braking of the vehicle is necessary by switching the drivetrain to the 4WD configuration.

[0094] In Fig. Figure 5 shows a camera module 85 or radar module 87 that captures information about the road ahead of vehicle 1. A target object (another vehicle 412) is detected ahead of vehicle 1. Information from the camera 85 and / or radar module 87 can indicate whether vehicle 1 needs to brake, for example, because the target object is stopping or braking, or because vehicle 1 is approaching the target object too quickly. Vehicle 1 uses the signal from the camera 85 or radar module 87 to determine whether it is necessary to brake preventively by switching the drivetrain to the 4WD configuration.

[0095] In Fig. Figure 6 illustrates the use of traffic information from an external operator 422. The traffic data is collected by the external operator 422. For example, the external operator 422 may have a network of sensors or cameras 420 distributed across a road network. Vehicle 1 receives the traffic data, for example, via a radio module 83. Vehicle 1 uses the traffic data to determine whether it is necessary to brake preventively. For example, vehicle 1 may use information about its current position and / or route to determine whether the traffic data is relevant to its route.

[0096] When the control element 40 causes the powertrain 5 to operate in two-wheel drive mode, the VCU 1C is repeatedly configured to determine whether a transition to all-wheel drive should occur. The transition to all-wheel drive can be advantageous by increasing the amount of charge that can be generated by the CIMG 16 when driven by the powertrain 5 as a generator to effect regenerative braking of the vehicle 1. This can also have the advantage of reducing wear on the vehicle's friction brakes associated with the braking system.

[0097] The VCU 1C can be designed to determine whether the vehicle should be braked preventively by causing the powertrain 5 to switch to all-wheel drive based on one or more of the following parameters: (a) a signal indicating the probability that the vehicle will have to come to a complete stop or slow down to a relatively low speed at a certain time; (b) Longitudinal acceleration of the vehicle; (c) Slope of the road surface; (d) Coefficient of surface friction between the wheels of the vehicle and the road surface; (e) Operating mode in which the vehicle is located; (f) Engine / powertrain mode in which the vehicle is operated; (g) State of charge (SOC) of vehicle battery 1B; and (h) Vehicle speed.

[0098] A transition to all-wheel drive may be prohibited if the VCU 1C causes the vehicle to operate in the hybrid locking mode of the engine / drivetrain, or if the state of charge (SOC) of battery 1B exceeds a predetermined value. In the present embodiment, the predetermined SOC is 100% of the maximum permissible SOC during normal use of vehicle 1. Other values ​​may be useful in some embodiments, such as 95%, 90%, or any other suitable value. It should be noted that the maximum permissible SOC during normal operation may be lower than the actual maximum capacity of battery 1B in order to increase battery 1B's service life. Likewise, the minimum permissible SOC during normal operation may be higher than the actual absolute minimum SOC that battery 1B can achieve in order to increase battery 1B's service life.

[0099] Similarly, in some driving modes, switching to all-wheel drive mode may be prohibited in order to avoid, reduce or prevent, for example, noise, vibration or harshness (NVH) associated with switching to all-wheel drive mode.

[0100] A transition to all-wheel drive mode can be prohibited by reference to the value of a parameter long_acc, which specifies the vehicle's longitudinal acceleration, a parameter surface_incl, which specifies the inclination of the driving surface, and a parameter surface_mu, which specifies the coefficient of friction between the vehicle's wheels and the driving surface.

[0101] The value of the parameter surface_mu is arranged to vary from a value of essentially zero, which represents a relatively slippery surface corresponding to wet ice, to a unit value, which represents a relatively grippy surface, such as dry asphalt.

[0102] In some situations, the control system may be designed so that, if it is determined that the vehicle needs to be braked preventively, the drivetrain is operated in a second configuration (4WD) and a friction-based wheel braking system is used, for example in situations where a lot of braking is required and conditions allow wheel braking.

[0103] In other situations, the control system may be designed so that, when the vehicle is in a second configuration (4WD), the amount of regenerative braking occurring within the system is moderated, or the ratio of regenerative braking to friction braking is modulated to optimize energy recovery during braking while maintaining vehicle control and stability. The amount of regenerative braking may depend on one or more of the following parameters: (a) a signal indicating the probability that the vehicle will have to come to a complete stop or slow down to a relatively low speed at a certain time; (b) Longitudinal acceleration of the vehicle; (c) Slope of the road surface; (d) Coefficient of surface friction between the wheels of the vehicle and the road surface; (e) Operating mode in which the vehicle is located; (f) Engine / powertrain mode in which the vehicle is operated; (g) State of charge (SOC) of vehicle battery 1B; and (h) Vehicle speed.

[0104] It should be noted that some embodiments of the present invention can be used with a number of different drivetrain types, including drivetrains in which a rear axle assembly of a vehicle is arranged to be permanently driven, while the front axle assembly is arranged to be driven only when the all-wheel drive is engaged, as well as drivetrains in which a front axle assembly is arranged to be permanently driven, while the rear axle assembly is arranged to be driven only when the all-wheel drive is engaged, as in the case of drivetrain 5 of the embodiment of Fig. 1.

[0105] In Fig. Figure 7 shows a part of a vehicle 100 according to a further embodiment of the present invention. The same features of the embodiment of Fig. 7 to which the embodiment of the Fig. Numbers 1 are displayed with the same reference symbol, increased by 100.

[0106] The vehicle 100 has a drivetrain 105 with a PTU 124, which includes a PTC (not shown) designed to allow a driveshaft 123 to be connected to a gearbox 118. At the opposite end of the driveshaft 123, a rear drive unit 130 with a clutch 127 in the form of a multi-plate wet clutch is provided. The RDU 130 also has a differential gear assembly 131 for driving the left and right rear drive shafts 126, respectively. The clutch 127 is designed to connect the driveshaft 123 to an input part of the differential gear assembly 131.It should be noted that the control element 140 is designed to cause the vehicle 100 to operate in two-wheel drive mode by controlling the PTU 124 to disconnect the driveshaft 123 from the transmission 118, and controlling the clutch 127 of the RDU 130 to disconnect the driveshaft 123 from the differential 131. The control element 140 is also designed to cause the vehicle to operate in four-wheel drive mode by controlling the PTU 124 to connect the driveshaft 123 to the transmission 118, and controlling the clutch 127 of the RDU 130 to connect the driveshaft 123 to the differential 131. In the embodiment of the . Fig. 7. The PTU 124 comprises a PTC in the form of a multi-disc wet clutch. In an alternative embodiment, the PTC is designed in the form of a jaw clutch, wherein the PTU 124 also has a synchronizing device for synchronizing the rotational speed of the input and output parts of the PTC when this is necessary to close the jaw clutch.

[0107] The drive train 105 of the embodiment of Fig. 7 is not designed to permit the application of a transverse axle lock between the rear wheels 114, 115 of the drive train 5. However, in some alternative embodiments, means may be provided to lock the rear drive shafts 126 together in such a way as to substantially prevent relative rotation. For example, in some embodiments the rear drive shafts 126 may be arranged so that they are locked together by a coupling arrangement.

[0108] In Fig. Figure 8(a) shows a part of a vehicle 200 according to a further embodiment of the present invention. Fig. Figure 8(b) shows an enlarged view of part of the powertrain 205 of the vehicle 200 shown in (a) and details relating to the PTU 224 are shown. The same features of the embodiment of Fig. 8 to which the embodiment of the Fig. Numbers 1 are displayed with the same reference symbol, increased by 200.

[0109] The 205 powertrain features a 223A PTU input shaft ( Fig. 8(b)) which is rigidly connected to a gearbox 218, a front driveshaft 223F which can be connected to the PTU input shaft 223A via a power transmission coupling (PTC) 222, and a rear driveshaft 223R which is connected to the PTU input shaft 223A via a differential gear assembly (or a “differential”) 225. In the embodiment shown, the differential 225 can be referred to as a “center differential” or “center diff” and is part of the PTU 224. The differential 225 allows the front and rear driveshafts 223F, 223R to rotate at different speeds.

[0110] The rear driveshaft 223R is connected to an RDU 230, which is designed to allow the rear driveshaft 223R to be connected to and disconnected from the rear wheels 214, 215. In the embodiment of the Fig. 8. The RDU 230 is similar to the RDU 130 in the version of Fig. 7, although other types of RDU may also be useful, such as RDU 30 of the embodiment of Fig. 1.

[0111] The PTC 222 enables the front driveshaft 223F to be detachably connected to the PTU input shaft 223A via a chain drive 224C. The PTC 222 is a multi-disc wet clutch in the embodiment of Fig. 8, although other types of couplings may also be useful in some embodiments, such as a dog clutch. The front driveshaft 223F is in turn arranged to drive a pair of front drive shafts 219 via a front differential unit 219D. The front differential unit 219D has a differential gear arrangement that allows the driveshafts 219 to rotate at different speeds.

[0112] In some embodiments, the PTU 224 can also be provided without the differential 225. Fig. Figure 9 shows a part of a powertrain 305 with such a PTU. The same features of the embodiment of Fig. 9 to which the embodiment of the Fig. Numbers 1 are displayed with the same reference symbol, increased by 300.

[0113] In the arrangement of the Fig. 9 A single driveshaft 323 connects the gearbox 318 via the PTU 324 to an RDU (not shown). The PTU 324 includes a PTC 322 in the form of a multi-plate wet clutch 322 ( Fig.9(b)), which is designed such that the driveshaft 323 can be connected to a front driveshaft 323F, which in turn is arranged to drive a front differential unit 319D. The PTC 322 is arranged to drive the front driveshaft 323F via a chain drive 324C. It should be noted that in some embodiments the front differential unit 319D may be equipped with a clutch, e.g. a multi-plate wet clutch, so that the part of the drivetrain between the PTC 322 and the clutch of the front differential unit 319D can be disconnected from the drive shafts 319.

[0114] The words “comprise” and “contain” and variations of the words, for example “comprehensive” and “encompasses”, mean throughout the description and claims of this specification “including but not limited to” and are not intended to exclude, and do not exclude, any other units, additions, components, integer values ​​or steps.

[0115] Throughout this description and the requirements of this specification, the singular includes the plural unless the context requires otherwise. In particular, when the indefinite article is used, the specification is to be understood as referring to both singularity and plurality, unless the context requires otherwise.

[0116] Features, integer values, properties, compounds, chemical units or groups described in connection with a particular aspect, embodiment or example of the invention are to be understood as applicable to any other aspect, embodiment or example described herein unless they are incompatible with it.

Claims

[1] Control system designed to control the powertrain of a motor vehicle so that it operates in a selected configuration from a variety of configurations, the control system is designed to receive an environmental indicator signal that shows the presence of traffic lights in front of the vehicle, the control system is designed to predict, based on the ambient display signal, whether it is necessary to bring the vehicle to a standstill or to brake to a relatively low speed at a given time, wherein the control system is designed so that, if it is predicted that the vehicle will need to come to a standstill or decelerate to a relatively low speed at a certain time, the powertrain is made to operate in a second configuration rather than a first configuration before a braking torque is requested from the braking system by a driver or an automatic control system, wherein the control system is designed to perform regenerative braking when a braking torque is required, wherein wheels connected to the drivetrain cause one or more electric machines coupled to the drivetrain to generate electrical current for storage in a charging storage device, wherein in the first configuration a first group of one or more wheels are arranged for propulsion by the drive train and in the second configuration the first group of one or more wheels and additionally a second group of one or more wheels are arranged for propulsion by the drive train. [2] Control system according to claim 1, wherein the ambient display signal further indicates a status of the traffic lights. [3] Control system according to any of the preceding claims, wherein the control system is designed to receive a signal indicating traffic in front of the vehicle, and wherein the prediction of whether the vehicle needs to come to a standstill or slow down to a relatively slow speed is based on this signal. [4] Control system according to one of the preceding claims, wherein the control system is designed to receive a signal indicating at least one of traffic density and traffic speed, and wherein the prediction of whether the vehicle needs to come to a standstill or slow down to a relatively slow speed is based on this signal. [5] Control system according to any of the preceding claims, wherein the control system is designed to receive a signal indicating a speed limit, and wherein the prediction of whether the vehicle must come to a standstill or slow down to a relatively slow speed is based on this signal. [6] Control system according to one of the preceding claims, wherein the environment display signal is received from a camera. [7] Control system according to one of the preceding claims, wherein the environment display signal is received by a radar module that displays objects relative to the vehicle. [8] Control system according to one of the preceding claims, wherein the radar module displays at least one of the position of objects relative to the vehicle and the speed of objects relative to the vehicle. [9] Control system according to one of the preceding claims, wherein the ambient display signal is received from a data link to the vehicle. [10] Control system according to any of the preceding claims, wherein the control system is designed to use a combination of map data and the environment display signal to determine whether the vehicle needs to be braked. [11] Control system according to any of the preceding claims, wherein the control system is designed to predict whether the vehicle needs to come to a standstill or slow down to a relatively low speed based on at least one of the following parameters: a measure of the vehicle's longitudinal acceleration; a slope of the road surface; Gradient; a parameter that specifies a surface friction coefficient between one or more wheels and a road surface; a selected driving mode in which the vehicle is operated, the driving mode being selected from a variety of driving modes. [12] Control system according to claim 11, wherein the control system is further designed to determine the amount of regenerative braking. [13] Control system according to claim 12, designed to calculate the amount of regenerative braking power required depending on one or more of the following parameters: (a) a signal indicating the probability that the vehicle will have to come to a complete stop or slow down to a relatively low speed at a certain time; (b) Longitudinal acceleration of the vehicle; (c) Slope of the road surface; (d) Coefficient of surface friction between the wheels of the vehicle and the road surface; (e) Operating mode in which the vehicle is located; (f) Engine / powertrain mode in which the vehicle is operated; (g) State of charge (SOC) of vehicle battery 1B; and (h) Vehicle speed. [14] Powertrain in combination with a system according to any preceding claim. [15] Motor / drive train comprising a drive train and a system according to any one of claims 1 to 13. [16] Motor vehicle comprising a powertrain and a system according to any one of claims 1 to 13. [17] Motor vehicle comprising: a body, a plurality of wheels, an engine / drivetrain for driving the wheels, wherein the engine / drivetrain comprises a drivetrain and a braking system for braking the wheels, and a system according to any one of claims 1 to 13. [18] Method for controlling a powertrain of a motor vehicle for operation in a selected configuration from a plurality of configurations, the method comprising: Receiving an ambient signal indicating the presence of traffic lights in front of the vehicle; Predictions based on the ambient display signal as to whether it is necessary to bring the vehicle to a standstill or to slow down to a relatively low speed at a specific time; and If it is predicted that the vehicle will need to come to a standstill or decelerate to a relatively low speed at a certain time, and before a driver or an automatic control system requests a braking torque from the braking system, to cause the powertrain to operate in a second configuration, rather than a first configuration, Applying regenerative braking when braking torque is required, wherein wheels connected to the drivetrain cause one or more electric machines coupled to the drivetrain to generate electrical current for storage in a charging storage device, wherein in the first configuration a first group of one or more wheels are arranged for propulsion by the drive train and in the second configuration the first group of one or more wheels and additionally a second group of one or more wheels are arranged for propulsion by the drive train. [19] Carrier medium containing computer-readable code for controlling a vehicle to perform the method according to claim 18. [20] Computer program product executable on a processor to implement the method of claim 18. [21] Computer-readable medium loaded with the computer program product according to claim 20. [22] Processor configured to implement the method of claim 18 or the computer program product of claim 20.

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