Powertrain lead actuator selection

Abstract

Aspects of the present invention relate to a control system (100), a system, a vehicle (1), a method and computer readable instructions. The control system (100) is suitable for outputting a lead actu

Description

9^90 £L TECHNICAL FIELD The present disclosure relates to a powertrain lead actuator selection. Aspects of the invention relate to a control system, to a system, a vehicle, a method and to computer readable instructions. 5 BACKGROUND Automatic and automated gearshifts are used commonly in vehicles (such as hybrid vehicles, both Plug-in Hybrid Electric Vehicles (PHEV) and Mild Hybrid Electric Vehicles (MHEV)) and provide a number of benefits to the driver, for example increased vehicle performance, greater fuel efficiency, and relieving the need for the 10 driver to change gears manually. In automatic transmission systems, it is known to provide different operational modes for different driving scenarios, or user requested driving experiences. It is also known to provide torque modulation, which is alternatively known as a torque intervention, during an automatic transmission shift (both for upshifts and downshifts) when the vehicle changes gears automatically during such operational modes. 15 However, when a vehicle is in a certain operational mode there is the potential that the user is expecting a certain characteristic of said operational mode. There is the potential that the torque supplied by a specific actuator is not suitable to provide that characteristic. This may result in an altered driving feel, or experience, than the user was expecting. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a control system, a system, a vehicle, a method and computer readable instructions as claimed in the appended claims. 25 According to an aspect of the present invention there is provided a control system for outputting a lead actuator request signal for a powertrain of a vehicle with two or more actuators, the control system comprising one or more processors, the one or more processors collectively configured to: receive the following input parameters: an operational mode of the vehicle; data relating to a key characteristic of the operational mode; a torque 30 intervention request signal; in dependence upon the torque intervention request signal signalling a torque intervention, identify an actuator of the two or more actuators in dependence on the key characteristic of the operational mode while providing at least part of the torque intervention; generate a lead actuator selection request signal to request the use of the identified actuator as a lead actuator for the torque intervention; and output the lead actuator selection request signal. 35 According to another aspect of the present invention there is provided a control system for outputting a lead actuator request signal for a powertrain of a vehicle with two or more actuators, the control system comprising one or more processors, the one or more processors collectively configured to: receive the following input parameters: an operational mode of the vehicle; data relating to a key characteristic of the operational mode; 40 a torque intervention request signal; in dependence on the torque intervention request signal signalling a torque intervention: identify an actuator of the two or more actuators for providing at least part of the torque 13 0555 intervention in dependence on the key characteristic of the operational mode; generate a lead actuator selection request signal to request the use of the identified actuator as a lead actuator for the torque intervention; and output the lead actuator selection request signal. 5 In this way, hybrid vehicles having more than one power source can most appropriately select the lead actuator for torque interventions to meet the needs of an operational mode of a vehicle, such as a Sports Mode, or an Eco Mode, or a Comfort Mode. Torque interventions include but are not limited to gear changes. For example, on one hand and in Sports Mode, the lead actuator may be chosen as an engine rather than an electric machine because an engine can deliverthe key characteristic of the Sports Mode much betterthan an electric 10 machine, owing for example to the noise and vibrations generated by an engine. On the other hand, in Comfort Mode, the lead actuator may be chosen to provide a quieter torque intervention with fewer vibrations and a smoother feel. In both examples, the driver or passengers’ experience is improved by the careful selection of the lead actuator. The inventors have found that this sensory feedback to the user can be provided without the addition of additional expensive components but rather by an inventive refinement of the control system logic 15 for selection of a lead actuator dependent upon the operational modes. The result is a more tactile driving experience which can be changed by updating the current driving mode to provide targeted sensory feedback. The key characteristic is a feature or quality of the operational mode that indicates a requested feedback to the user. The requested feedback is something that increases the overall enjoyment of the driver and their passengers if present -the user(s). For example, the feedback is in the form of sensory feedback (e.g. audio feedback and / or haptic feedback or vibrational feedback). Such feedback makes the operational mode of the vehicle more recognizable to the user with certain operational modes having a first key characteristic that is different to a second operational mode with a second key characteristic. In the example where the feedback is an audio feedback in the first operational mode the audio feedback would be at a first decibel level, and in 25 the second operational mode the audio feedback would be at a second decibel level- wherein the second decibel level is higher than the first decibel level. The feedback is provided by (or at least provided at least in part by) one actuator of the two or more actuators. According to an aspect of the present invention there is provided a control system for outputting a lead actuator 30 request signal for a powertrain of a vehicle with two or more actuators, the control system comprising one or more processors, the one or more processors collectively configured to: receive the following input parameters: an operational mode of the vehicle; data relating to a key characteristic of the operational mode; a torque intervention request signal; in dependence upon the torque intervention request signal signalling a torque intervention, identify an actuator of the two or more actuators in dependence on the key characteristic of the 35 operational mode while providing at least part of the torque intervention. The control system of this aspect has the same advantages of that of the previously described control system. According to either previous aspect, the control system comprises one or more controllers collectively 40 comprising at least one electronic processor having an electrical input for receiving an input signal; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored 9^90 £L therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions thereon so as to: receive the following input parameters: an operational mode of the vehicle; data relating to a key characteristic of the operational mode; a torque intervention request signal; in dependence upon the torque intervention request signal signalling a torque intervention, identify an 5 actuator of the two or more actuators in dependence on the key characteristic of the operational mode while providing at least part of the torque intervention; generate a lead actuator selection request signal to request the use of the identified actuator as a lead actuator for the torque intervention; and output the lead actuator selection request signal. 10 Optionally, the operational mode of the vehicle comprises one or both of: a transmission operating mode, and a driving operating mode comprising one or more sub-system modes indicating an operation of one or more vehicle sub-systems. The transmission operating modes may include at least one selected from amongst a Park, Reverse, Neutral, 15 Drive mode, and Sport mode. These transmission positions are selectable in both High Range (focuses more on on-road driving and the comfort of the passenger) and Low Range (focuses more on off-road capability) and a manually selectable gear mode. The sport mode may be a performance-oriented transmission mode in which gearshift information is modified compared with that employed in the drive mode so as to cause one or more upshifts to occur at higher engine speeds. The transmission may therefore be held in a lower gear for longer periods of time. The driving mode may correspond to one or more terrain response modes. Optionally, the one or more vehicle sub-systems include at least one selected from amongst a powertrain controller arranged to select a correspondence between accelerator control and powertrain torque in dependence at least in part on the 25 driving operating mode, a suspension control system, a steering control system and a brake control system. Optionally, the input parameters comprise one or more stop flags, each of the one or more stop flags having an active state and an inactive state; and wherein when one of the one or more stop flags is in the inactive state the one or more processors are collectively configured to identify an actuator of the two or more actuators 30 in dependence on the key characteristic of the operational mode or the use thereof. The stop flag prevents the requesting of a lead actuator in dependence on the operational mode and associated key characteristic where there is an overriding reason. The stop flag may be binary, where in an inactive state (0) the stop is not active and will the identify the lead actuator in dependence on the operational 35 mode. Optionally, the input parameters further comprise a default lead actuator identifier, the default lead actuator being the required actuator for use whilst a stop flag is in an active state; and when the stop flag is in the active state the one or more processors are collectively configured to 40 identify the default lead actuator as the identified actuator. 9^90 £L The control system determines whether to output the selected lead actuator request or to default to a default actuator request. The default actuator is utilised where there is a determination by the control system not to request a lead actuator in dependence on the operational mode and associated key characteristic as there is an overriding reason not to do so. 5 Optionally, the one or more stop flags comprises one or more hard stop flags; and wherein if a hard stop flag is in the active state the hard stop flag will remain in the active state during a torque intervention indicated by the torque intervention request signal. 10 The hard stop flag, if active, will remain active throughout a gear shift or other similar intervention process. Advantageously, this prevents the control system logic selecting an alternative lead actuator after the torque intervention signal has been received. Optionally, the one or more hard stop flags comprises one or more of: a stability control intervention flag; a no 15 gearshift flag; and hybrid system health information flag. The hard stop flag relates to an indication that a stability control intervention has occurred, in this way it prevents the vehicle from potentially changing which actuator is the lead actuator when there is a reduction in driving stability due to environmental conditions. For example, in the case of reduced traction on a road surface due to snow or icy conditions. Where the hard stop flag is data relating to a no gearshift flag this prevents the control system from requesting a lead actuator in dependence on the operational mode and associated key characteristic where the gearshift has not proceeded due to some overriding control logic outside the current control system. 25 Where the hard stop flag relates to hybrid system health information the requesting of a lead actuator in dependence on the operational mode and associated key characteristic may not proceed if the hybrid system health information is indicative of a problem with the health of the hybrid system. For example, one such problem may be that a battery of the hybrid system is in an uncharged or low charged state in which case it 30 would not be appropriate for the control system to request the electric machine to be the lead actuator even if the electric machine was most able to satisfy the operational mode key characteristic. Optionally, the one or more stop flags comprises one or more soft stop flags having an active state and an inactive state; and wherein each of the soft stop flag is changeable between the active state and the inactive 35 state during a torque intervention indicated by the torque intervention request signal. The soft stop flag is a flag which can change for example during a gearshift. If the soft stop flag remains active during the gearshift the control system in the same way as a hard stop flag. Should the soft stop flag change from the active state to the inactive state then the control system will then identify the lead actuator based on 40 the operational mode and key characteristic thereof. 13 0555 Optionally, the one or more soft stop flags comprise one or more of: an incorrect intervention type flag; an insufficient torque flag. Optionally, the torque intervention request signal comprises: a torque demand and an indication of 5 transmission input shaft speed; and the data relating to the key characteristic includes a prioritised lead actuator identifier, the prioritised lead actuator identifier is dependent on the torque demand and the indication of transmission input shaft speed; and wherein the one or more processors are collectively configured to identify the actuator of the two or more actuators in dependence on the key characteristic of the operational mode using the prioritised lead actuator identifier. 10 In such a case the lead actuator chosen by the control system is dependent upon the torque-speed demand of the torque intervention request. This technique can result in a relatively elegant implementation. Optionally, the data relating to the key characteristic comprises a look-up table comprising: a plurality of 15 prioritised lead actuator identifiers, a plurality of torque demands, and a plurality of indications of transmission input shaft speed, wherein each of the plurality of prioritised lead actuator identifiers depends on a torque demand and an indication of transmission input shaft speed pair; wherein the step of identifying the actuator as the actuator further comprises the step of: comparing the torque demand and the indication of transmission input shaft speed with the look-up table torque demand and indication of transmission input speed to identify an actuator as the actuator. In this way, the control system can quickly determine the required lead actuator by comparing the vehicle torque demand and transmission input shaft speed demand with one or more pre-saved pairings in the lookup table. This advantageously reduces calculation time in practice as each operational mode can have its own 25 individually tailored look-up table which provides different lead actuator identified for the same torque-speed pairings. The key characteristic of the operational mode comprises data relating to one or more of: an engine sound quality, a vibration and a modified torque demand. 30 In such a case where the key characteristic relates to an engine sound quality sensory feedback is provided to the user by means of the engine. Where the key characteristic relates to vibration then sensory feedback is provided to the user by means of the engine or electric machine. Where the key characteristic is a modified torque demand, the modified torque demand causes the torque intervention to be over torqued or under 35 torqued as compared to a base line level requested by the torque intervention request. Optionally, the input parameters further comprising a look-up table for identifying default lead actuators; the look-up table comprising: a plurality of default lead actuator identifiers, a plurality of torque demands, and a plurality of transmission input shaft speed demands, wherein each of the plurality of default lead actuator 40 identifiers depends on a torque demand and a transmission input shaft speed demand pair, wherein the step of identifying the default lead actuator as the actuator further comprises the step of: comparing the torque 13 0555 demand and transmission input shaft speed demand with the default look-up table torque demand and transmission input speed demand to identify a default lead actuator as the actuator. The provision of a look-up table enables the control system to quickly identify the appropriate default actuator 5 for a specific torque-speed demand pairing. This advantageously reduces calculation time in practice. According to an aspect of the present invention there is provided a system comprising the control system of any previous aspect and a first actuator and a second actuator. 10 According to an aspect of the present invention there is provided a vehicle comprising the system of the previous aspect or any of the control system aspects. According to an aspect of the present invention there is provided a method for outputting a lead actuator request signal for a powertrain of a vehicle with two or more actuators, the method comprising: receiving the 15 following input parameters: an operational mode of the vehicle; data relating to a key characteristic of the operational mode; a torque intervention request signal; in dependence upon the torque intervention request signal signalling a torque intervention, identify an actuator of the two or more actuators in dependence on the key characteristic of the operational mode while providing at least part of the torque intervention; generate a lead actuator selection request signal to request the use of the actuator as a lead actuator for the torque intervention; and output the lead actuator selection request signal. The same advantages of this additional method are also present as described above in relation to the other method. Similarly, the method provides the advantages of the preceding aspects. The method may comprise the further restrictions of any of the preceding aspects. For example, the method may further comprise any 25 control system and / or any of the embodiments thereof. Likewise, the method may comprise the system and / or vehicle. According to an aspect of the present invention there is provided computer readable instructions which, when executed by a computer, are arranged to perform a method according to the previous aspect. 30 Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in anyway and / or combination, 35 unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS 40 13 05^25 One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a vehicle in accordance with an embodiment of the invention; 5 Figure 2 shows a schematic example of a powertrain of a vehicle in accordance with the embodiment of Figure 1; Figure 3 shows a control system in accordance with an embodiment of the invention; 10 Figure 4 shows a flow chart in accordance with an embodiment of the invention; Figure 5 shows a flow chart in accordance with an embodiment of the invention; 15 Figure 6 shows a flow chart in accordance with an embodiment of the invention; DETAILED DESCRIPTION A control system 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1 to 6. The control system 100 is suitable for controlling a power train of a vehicle 1 with two actuators 24, 26. As shown in Figure 2, the control system 100 is installed in a vehicle 1. The vehicle 1 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 1. In some, but not necessarily all examples, the vehicle 1 is a passenger vehicle, also referred to as a passenger car or as an automobile. In other examples, embodiments of the invention can 25 be implemented for other applications, such as commercial vehicles. Figure 2 schematically illustrates an example of at least part of a powertrain of the vehicle 1. In this example, the vehicle 1 powertrain comprises a propulsion system 22 comprising a plurality of torque sources 24, 26 (also referred to generically as: actuators 24, 26 or power sources 24, 26) which are selectively operable for the purpose of providing drive torque for accelerating the vehicle 1. A torque source refers to a 30 prime mover, such as an internal combustion engine, an electric machine such as a traction motor, or the like. In the illustrated example, the propulsion system 22 comprises two torque sources 24, 26. A first torque source 24 is an internal combustion engine (‘engine’). A second torque source 26 is an electric machine 26. In further examples other torque sources may be present. The electric machine 26 is an electric motor arranged to convert electrical energy into kinetic energy in the 35 form of mechanical torque and is also arranged to convert kinetic energy in the form of kinetic energy into electrical energy. The electric machine 26 may be an alternating current induction motor or a permanent magnet motor, or another type of suitable electric machine. The electric machine 26 is a traction motor configured to enable at least an electric mode comprising electric-only driving. That is, the electric machine 13 05 25 26 can drive the vehicle 1 by itself (without an engine). Another term for the electric machine 26 is an electric drive unit (EDU). The propulsion system 22 is configured to operate in a plurality of predefined operating modes. These include at least an electric mode and a parallel hybrid mode - in further examples the plurality of predefined operating 5 modes comprises other operating modes. In the electric mode (also known as electric vehicle (EV) mode or electric-only mode) the vehicle 1 is propelled only by torque generated by the electric machine 26, with the engine clutch 25 handling whether the engine is connected to the drivetrain and part of the torque path to the wheels 34. In the parallel hybrid mode the vehicle 1 is propelled by torque generated by both the engine 24 and by the 10 electric machine 26. Transitioning between predefined operating modes of the propulsion system 22 comprises turning on, or off, one of the torque sources 24, 26 so that, respectively, it either does or does not output torque. In some examples, transitioning between predefined operating modes may further comprise mechanically connecting (coupling) ordisconnecting (uncoupling) one of the torque source 24, 26 to the drivetrain. It will be appreciated 15 that the transition between the predefined operating modes is not instantaneous. While the propulsion system 22 is transitioning between predefined operating modes, its mode status is ‘in transition’. The vehicle 1 comprises an automatic transmission system 10 comprising an automatic transmission 12 and the control system 100 such as a transmission control unit / module for controlling the automatic transmission 12. The automatic transmission 12 comprises an input clutch 14 (also generically known as a coupling element 14) which transfers torque output by the operating torque sources 24, 26 of the propulsion system 22 to the transmission input shaft 18. The input clutch 14 may be a wet clutch such as a torque converter or one or more automatically-actuated friction clutches as found in, for example, a dual-clutch transmission. The automatic transmission 12 also comprises a gear set and accompanying shifting mechanism, referenced 25 in combination as combined gear-shift mechanism 16. The gear set comprises a plurality of gears which are selectively couplable into different gear trains to enable multiple gear ratios between the transmission input shaft 18 and the transmission output shaft 20. The clutches and their actuators 24, 26 form the shifting mechanism. The shifting mechanism is controlled to establish a selected gear ratio in accordance with a control signal 30 output by the control system 100, alternatively this may be achieved by a second control system within the vehicle connected or connectable to and in communication with the first control system 100 of the present invention. The control system 100 is also capable of controlling actuation of the input clutch 14. The transmission output shaft 20 is connected to a final set of gears 32, such as a pinion gear meshed with a 35 ring gear, to transfer torque to the wheel axles and thus the vehicle wheels 34. 8 13 05 25 In order to store electrical energy for the electric machine 26, the vehicle 1 comprises an electrical energy storage means 28. The electrical energy storage means 28 can be a traction battery. The traction battery 28 provides a nominal voltage required by electrical power users such as the electric machine 26. The traction battery 28 may be a high voltage battery. The traction battery 28 may have a voltage and capacity 5 to support electric only driving for sustained distances. The traction battery 28 may have a capacity of several kilowatt-hours, to maximise range. The capacity may be in the tens of kilowatt-hours, or even over a hundred kilowatt-hours. Although the traction battery 28 is illustrated as one entity, the function of the traction battery 28 could be implemented using a plurality of small traction batteries in different locations on the vehicle 1. 10 An inverter 30 converts between the DC output of the traction battery 28 and the AC input required for the electric machine 26. In view of the above description of the vehicle 1, it will be understood that the vehicle 1 is a full hybrid electric vehicle (HEV). However, in some examples the vehicle 1 may be otherthan as shown in Figure 2. The vehicle 1 may be a battery electric vehicle (BEV), a plug-in electric hybrid vehicle (PHEV), a mild hybrid electric vehicle 15 (MHEV), an internal combustion engine vehicle (ICEV) or otherwise. MHEVs do not have an electric-only mode of propulsion, but the electric machine 26 may be configured to provide assistance such as boosting output torque of the engine 24. In such vehicles the electric machine 26 is not sufficiently powerful to drive the vehicle 1 under electric power alone. BEVs are an electric-only vehicles which are propelled by an electric machine 26 which receives power from an on-board traction battery 28. ICEV are propelled solely by an engine 24. Any on-board electric machine is used only as a startergenerator. The vehicle 1 has one or more operational modes. The vehicle 1 has a control system (either control system 100 or an additional control system electrically connected to control system 100) for implementing the 25 operational mode. The operational modes have one or more transmission operating modes. The transmission operating mode is optionally selectable by the control system. The transmission operation modes affect the automatic transmission 12 and the accompanying shifting mechanism 16. 30 The transmission operating modes include such modes as a Park, Reverse, Neutral, Drive mode, and Sport mode. These transmission positions are selectable in both High Range (which has a focus on on-road driving and comfort) and Low Range (which has a focus on off-road capability) and a manual gear shift mode. The sport mode is a performance-oriented transmission mode in which gearshift information is modified compared with that employed in the drive mode so as to cause one or more upshifts to occur at higher engine speeds. 35 The transmission may therefore be held in a lower gear for longer periods of time. 9 In some applications, such as for a PHEV vehicle 1, the engine may be latched on during the sport mode. 13 05 25 In addition, or optionally, the transmission mode may comprise a manual mode where the vehicle 1 is an automatic transmission vehicle 1. The manual mode can be a manual drive mode or a manual sports mode for example. The manual mode enables the user to have full control on the transmission 12. In effect this turns 5 the automatic vehicle 1 into a manual-automatic vehicle 1 when this mode is active. In addition, or optionally, the operating modes may include a driving operating mode such as one or more of a hybrid driving modes such as a standard, general or default hybrid driving mode, a selectable EV hybrid driving mode, an EV driving mode, and an 'auto stop-start off driving mode which may also be referred to as a 'hybrid inhibit' driving mode. The latter mode may correspond to the default hybrid driving mode but with the engine 10 latched on substantially permanently. The driving operating modes may also be referred to as terrain modes, terrain response modes, or control modes. As an example, six control modes can be provided: (a) an 'on-highway' driving operating mode suitable for driving on a relatively hard, smooth driving surface where a relatively high surface coefficient of friction exists between the driving surface and wheels of the vehicle; (b) a 'sand' driving operating mode suitable for 15 driving over sandy terrain; (c) a 'grass, gravel or snow' (GGS) driving operating mode suitable for driving over grass, gravel or snow; (d) a 'rock crawl' (RC) driving operating mode suitable for driving slowly over a rocky surface; (e) a 'mud and ruts' (MR) driving operating mode suitable for driving in muddy, rutted terrain; and (f) a 'dynamic' driving operating mode in which vehicle systems are configured for performance oriented driving. Other driving operating modes may be provided in addition or instead. A smaller number of driving operating modes may be provided in some embodiments. The driving operation modes may affect sub-systems of the vehicle 1. Such sub-systems are connected to the control system (either control system 100 or an additional control system electrically connected to control system 100). The sub-systems may be any combination of: a suspension control system that is used to control the suspension, e.g. control the dampening experienced in use to make the ride experience more comfortable 25 or firm; a steering control system arranged to control a power steering assist unit connected to a steering wheel of the vehicle 1, e.g. to make the steering feel heavier to the user; an engine and / or electric machine torque delivery (e.g. a pedal map, transient response and / or an overrun torque). For example, with the ‘on-highway’ driving operating mode (which may also be termed as a so-called ‘comfort’ mode) the suspension control system is utilised to make the suspension more comfortable for the driver or 30 their passengers, for example by increased dampening of the suspension system. For the dynamic mode, in comparison, the suspension may be changed using the suspension control system to make the driving experience firmer. Further, each of the operational modes have a key characteristic. The key characteristic is a parameter of the operational mode to be met to increase driver or passenger enjoyment of the vehicle. The key characteristic 35 comprises an engine sound quality. Engine sound quality metrics may be calculated by means and methods as known in the art. Engine sound quality metrics include loudness as calculated using ISO532B, sharpness, fluctuation strength, overall sound level (dBL / dBA), impulsiveness. The engine sound quality is mainly driven 13 05 25 by the frequency and order content of the sound at different engine speeds and / or loads. The engine sound quality may be a measure of exhaust loudness in dB. Optionally, or additionally, the key characteristic may compromise other parameters which affect the driver and / or passenger experience. 5 In an example a key characteristic is a vibrational parameter. The vibrational parameter is measured in ms 2. The vibrational parameter is a measure of vibration supplied by the actuator 24, 26 to the vehicle chassis to the driver’s seat or via the steering wheel to the driver. Increased vibration in a Sports mode as compared to a baseline level in a Comfort mode (for example) is used when the user expects a certain background feel or hum indicating the actuator 24 or actuator 26 is being utilised. The firing of engine cylinders in an engine 24 10 will have a different vibrational effect on the vehicle 1 than the electric machine 26 which has a decreased vibrational effect on the vehicle 1. Optionally, or additionally, the key characteristic may comprise a modified torque demand for a particular torque intervention request. The modification may be for example an increased torque demand of 100 Nm for a particular gear change in a Sports mode compared to a default torque demand in a default operational mode. 15 The increased torque demand means that the gear change will occur at a higher transmission input shaft speed and torque. The result of this is that the key characteristic is an overtorque fora particular gear change. The result felt by a driver of the vehicle 1 is a ‘jerk’ as the gear changes. The ‘jerk’ may be supplied to the driver through the steering column and steering wheel for example. This ‘jerk’ type feeling on the user enables a greater user experience because it indicates to the driver that they have greater control of the vehicle 1 than where no 'jerk’ is provided as the driver experiences an effect of the gear change themselves. Comparatively, for a comfort mode the gear change may occur at a lower transmission input shaft speed and torque, for example a decreased torque demand of 100 Nm for a particular gear change in a Comfort mode compared to a default torque demand in a default operational mode. The ‘under torque’ in this scenario may decrease the responsiveness of the vehicle in terms of acceleration however can provide a more comfortable driving 25 experience to the driver or their passengers. Different operational modes may have the same or a different key characteristic. For example, the sports mode will have a key characteristic with an engine sound quality with an increased loudness, for example, as compared to a drive mode. The comfort mode will have a key characteristic with an engine sound quality with a decreased loudness as compared to the sports mode. The comfort mode is intended to provide a key 30 characteristic which increases comfort of the user. Likewise, the terrain modes, terrain response modes, or control modes have a key characteristic with an engine sound quality with an increased loudness, for example, as compared to a drive mode. The engine sound quality of the vehicle 1 in different operational modes is important as the sounds emitted by the vehicle 1 alter the driver’s perception of the overall driving experience. 35 The vehicle 1 operational mode comprises one or both of a transmission mode and a driving operating mode. For example, the user may wish to utilise a sport mode (the transmission mode) and the dynamic mode (the driving operation mode) as part of a rally driving session or race. In such a scenario lead actuator selection is 13 0525 important as this can affect the user experience by providing sensory feedback in the form of the engine sound to the driver and passengers. At the same time, the lead actuator selection is also important for the spectators viewing the race, the sound emitted by the vehicle 1 can affect their enjoyment when watching a race, either on television or for example in a stand adjacent a racetrack. In such a case the selection of a lead actuator of 5 the engine 24 is necessary to provide the engine sound. The selection of an actuator24,26 as a lead actuator using the control system 100 to achieve the requirements of the key characteristic will be described below. With reference to Figure 2 and 3, the control system 100 will be described in more detail. The control system 10 100 comprises one or more processors 110. The control system 100 is configured to receive one or more input parameters 166. The input parameters 166 comprise: an operational mode of the vehicle, data relating to a key characteristic of the operational mode and a torque intervention request signal 165 that is indicative of a requirement to perform a torque intervention. 15 The control system 100 in dependence upon the torque intervention request signal signalling a torque intervention, identifies an actuator 24, 26 of the two or more actuators 24, 26 in dependence on the key characteristic of the operational mode while providing at least part of the torque intervention. The control system 100 may then generate a lead actuator selection request signal to request the use of the identified actuator as a lead actuator for the torque intervention. The control system 100 may then output the lead actuator selection request signal. The control system 100 as illustrated in Figure 3 comprises one processor 110, although it will be appreciated that this is merely illustrative and that more than one processor 110 may be provided. The processor 110 comprises processing means 120 and memory means 130. The processing means 120 may be one or more 25 electronic processing device 120 which operably executes computer-readable instructions. The memory means 130 may be one or more memory device 130. The memory means 130 is electrically coupled to the processing means 120. The memory means 130 is configured to store instructions, and the processing means 120 is configured to access the memory means 130 and execute the instructions stored thereon. 30 The processor 110 comprises an input means 140 and an output means 150. The input means 140 may comprise an electrical input 140 of the processor 110. The output means 150 may comprise an electrical output 340 of the processor 110. The processor 110 may have an interface comprising 111 the input means 140 and output means 150. The input means 140 is arranged to receive a torque intervention request signal 165 from a sensor. The torque intervention request signal 165 is an electrical signal which is indicative of a 35 requirement to perform a torque intervention. The input means 140 is also arranged to receive the one or more input parameters 166. The output 150 is arranged to output a control signal 155 being a lead actuator selection request signal. The control signal 155 requests the use of a lead actuator in dependence on the key characteristic of the operational mode whilst providing at least part of the torque intervention. 9^90 £L The control system 100 and steps undertaken by the one or more processors 110 to output a lead actuator selection request signal will be discussed in more detail with the aid of Figures 4 to 6. Figure 4 shows a schematic flow chart 200 of the determination of a lead actuator selection which takes place 5 in the control system 100. The flow chart 200 details the steps which are utilised by the control system 100 to identify a lead actuator from two or more actuators 24, 26 in order to provide a key characteristic expected by the driver. The result is that the driver and / or their passengers have a more enjoyable driving experience. In this flow chart steps which takes place within the control system 100 are represented by being located within the dashed line which represents the control system 100. 10 The control system 100 receives the input parameters 166 at step S-210. After receiving the input parameters 165, 166 at a step S-210 the control system 100 at step S-220 determines which of the two actuators 24, 26 to be selected as a lead actuator. This is achieved in dependence upon the torque intervention request signal signalling a torque intervention by identifying the actuator 24, 26 in dependence on the key characteristic of 15 the operational mode while providing at least part of the request torque intervention indicated by the torque intervention request signal 165. Optionally, the control system 100, or other control systems connected to the control system 100 may preferentially chose to prioritise the delivery of the required torque than provision of the key characteristic. In such a case a default actuator may be selected as will be discussed in more detail below with reference to Figures 5 and 6. Where the key characteristic comprises data relating to engine sound quality the engine 24 may be selected in preference to the electric machine 26 if the key characteristic requires increased loudness. Alternatively, if the key characteristic requires decreased loudness then the electric machine 26 may be selected in preference to the engine 24. The decrease or increase in loudness is with respect to a baseline prior to the intervention, 25 for example 1-5 seconds prior to the intervention. Where there is an increase in loudness from the engine 24 the user may experience a more ‘sporty’ sound in relation to the intervention, than if the intervention were carried out without the selected actuator 24, 26. Optionally, or alternatively, the increase in loudness is with respect to a baseline indicative of an intervention utilising the default lead actuator. 30 Optionally, the determination of the lead actuator 24, 26 may be obtained from a look-up table that the processor 110 is configured to access for example from a memory 130. For example, the key characteristic of the operational mode may include data relating to a prioritised lead actuator identifier. The processor 110 is configured to read the prioritised lead actuator identifier for the key characteristic and therefore select the prioritised lead actuator to be identified as the lead actuator. In such a case the key characteristic may have a 35 prioritised lead actuator identifier for any or all torque-speed pairings. When the key characteristic is one of vibration the engine 24 may be selected as the lead actuator in preference to the electric machine 26 if the key characteristic requires increased vibration. The increased vibration may be provided by the firing of cylinders of the engine 24 which will cause an increased vibration as compared to 40 a baseline of an electric machine 26 at a similar or same torque-speed pairing. The vibration provided by the electric machine 26 may be comparatively low vibration due to the type of electric machine 26 in the vehicle 13 0555 1. The electric machine may comprise a DC series motor, a brushless DC motor, a permanent magnet synchronous motor, a three phase AC induction motor, or a switched reluctance motor. In each case the conversion of electrical potential energy supplied by the electrical energy storage means 28 into kinetic energy by the electric machine 26 does not produce as great a vibrational event as does the firing of an engine 24 in 5 the cylinders of an internal combustion engine 24. Optionally, or alternatively, the increased vibration is with respect to a baseline indicative of an intervention utilising the default lead actuator. When the key characteristic is one of a modified torque demand the selection of a lead actuator from one of the two actuators 24, 26 may be the actuator most able to provide that modified torque demand to supply the 10 ‘jerk’ to the user. For example, the electric machine 26 may be selected in preference to the engine 24 as the electric machine 26 may be more able to alter its rotational shaft speed to supply the modified torque to the transmission input shaft and therefore the indication of transmission input shaft speed supplied can vary more quickly compared with the engine 24. Optionally, or alternatively, the opposite may be true and the engine 24 may be selected in preference to the electric machine 26 as the engine 24 is able to alter its rotational shaft 15 speed to supply the modified torque to the transmission input shaft and therefore the indication of transmission input shaft speed can vary more quickly compared to the electric machine 26. Subsequently at step S-230, a lead actuator selection request signal is generated by the control system 100. The lead actuator selection request signal is a signal that requests the use of the identified actuator 24, 26 as a lead actuator for use in a torque intervention. Next, at step S-240 the control system 100 outputs the lead actuator selection request signal to an actuator controller or other control systems connected to the control system 100. The lead actuator selection request signal may cause a control system connected to control system 100 (or optionally control system 100 itself) to 25 request at least a part of a torque intervention utilising the lead actuator requested from the first or second actuators 24, 26. The two actuators 24, 26 may each provide a part of the torque intervention as part of a combined torque intervention. The actuator 24, 26 chosen as the lead actuator will provide the majority of the torque as part of such an intervention. 30 The result is that at step S-250 the actuator 24 or actuator 26 provides its part of the torque intervention in order to meet the requirements of the key characteristic. Optionally the torque intervention request signal 165 also comprises a torque demand and an indication of transmission input shaft speed. Further, in such a scenario the key characteristic of the operational mode 35 includes data relating to a prioritised lead actuator identifier. The data relating to the prioritised lead actuator identifier is dependent upon the torque demand and the indication of transmission input shaft speed. At step S-220 the processor 110 may then determine the lead actuator by identifying which of the two actuators 24, 26 is the lead actuator using the prioritised lead actuator identifier. 40 Optionally, at step S-210 the determination of a lead actuator utilising a lead actuator identifier may be undertaken using a look-up table. The look-up table comprising a plurality of prioritised lead actuator identifiers, a plurality of torque demands and a plurality of indications of transmission input shaft speeds. Each of the prioritised lead actuator identifiers depends on a torque demand and an indication of transmission input shaft speed pair. The look-up table may be stored in the memory 130 and able to be read by the processor 110. The processor 110 is configured to read the look-up table and identify a prioritised lead actuator identifier as a 5 lead actuator. An example table [Table 1] is provided below: [Table 1] Indications of Transmission Input Shaft Speed (rpm) 1000 2000 3000 4000 Torque Demand (Nm) 0 1 1 1 1 200 1 1 1 0 400 1 1 0 0 600 1 1 0 0 13 05 25 10 The prioritised lead actuator identifier (indicated by ‘0’ or ‘1’ for each torque-speed pairing) represents for ‘0’ the engine 24 and for ‘1’ the electric machine 26. An optional flow chart 300 will be described with the aid of Figure 5. When undertaking the control system logic to choose a lead actuator, there may be an overriding reason not to select a lead actuator but instead revert to the use of a default actuator. For example, when a stability intervention is in progress (such as an Anti-lock Braking System (ABS) event) the selection of a different actuator to the default actuator may cause a decrease in the stability of the vehicle which should be avoided. To help ensure the safe operation of the vehicle 1 the control system logic of flow chart 300 checks for a ‘stop-flag’ the stop flag indicates that a default actuator selection should be made. Flow chart 300 shares a number of common features with flow chart 300, further features found in flow chart 300 will now be described. Optionally with respect to Figure 5 or in general, the input parameter 166 may comprise one or more stop flags. The stop flags are a signal received by the processors 110 from other control systems within the vehicle 1 or generated by the processors 110 themselves. The stop flags have an active 25 state and an inactive state. For example, the stop flag may be a binary ‘1 ’ (on) or ‘0’ (off) flag. The processor 110 is configured to identify the state of the stop flag at step S-204 in Figure 5. This decision is shown the decision box at step S-204 with two branches (a ‘Y’ branch and a ‘N’ branch). If the processor 110 identifies that the stop flag state is ‘0’ it causes the control system logic to move from step S-204 to step S-220 30 on the ‘N’ branch. Steps S-220, S-230, S-240 and S-250 are the same as those described above with respect to flow chart 200. The processor 110 when it identifies that the stop flag state is T causes the control system logic to move from step S-204 to step S-320 on the ‘Y’ branch. At step S-320 the processors 110 identify a default lead actuator selection. The default lead actuator selection is the required actuator to be used when the stop flag is active (‘1’). The default lead actuator selection may be either actuator 24 or 26. Subsequent to step S-320 the lead actuator selection request signal using the default actuator as the lead actuator is generated at step S-240 and then output at step S-250. Optionally, the determination of a lead actuator may be undertaken using a default actuator identifier look-up table in a similar fashion as the look-up table for the prioritised lead actuator look-up table. The look-up table comprising a plurality of default lead actuator identifiers, a plurality of torque demands and a plurality of indications of transmission input shaft speeds. Each of the default lead actuator identifiers depends on a torque demand and an indication of transmission input shaft speed pair. The look-up table may be stored in the memory 130 and able to be read by the processor 110. The processor 110 is configured to read the look-up table and identify a default lead actuator identifier as a lead actuator. An example table [Table 2] is provided below: [Table 2] Indications of Transmission Input Shaft Speed (rpm) 1000 2000 3000 4000 Torque Demand (Nm) 0 1 1 1 1 200 1 1 1 1 400 1 1 1 1 600 1 1 1 1 13 05 25 The default lead actuator identifier (indicated by ‘0’ or ‘1’ for each torque-speed pairing) represents for ‘0’ the engine 24 and for ‘1 ’ the electric machine 26. Optionally, the stop flag is a ‘hard stop’ flag. The hard stop remains active throughout or during a torque intervention. In other words, once the hard stop flag has been activated (T) it will not become inactive (‘0’) until the torque intervention has completed. Therefore, the hard-stop flag prevents the selection of a lead actuator other than the default actuator when, for example, a stability intervention is in progress as changing the lead actuator when a stability intervention is in progress may decrease the stability of the vehicle. The use of the hard-stop flag therefore helps ensure the safe operation of the vehicle. The selection of a default lead actuator is made when the hard stop flag is active as there may be an overriding reason not to undertake a torque intervention with the identified actuator in dependence on the key characteristic. For example, the hard stop flag may indicate that a: stability control intervention is occurring (such as anyone of, or combination of: anti-lock braking system (‘ABS’), a dynamic stability control, or a roll stability control) or there has been no gearshift made or that the hybrid system is in a low charged state. Optionally the stop flag may be a ‘soft-stop’ flag. The soft-stop flag is changeable between the active state ‘1 ’ and inactive state ‘0’ during a torque intervention. When the soft-stop flag is active ‘1 ’ the control system logic 16 13 0555 will cause a default actuator to be selected in the same or similar fashion as above with respect to flow chart 300. The advantage of a soft-stop flag is that there are some scenarios whereby a correctable issue has been identified, so it would not be necessary to overrule the control system logic entirely as with a hard-stop flag. If the issue is corrected prior to an intervention taking place the lead actuator can be selected. An example of 5 this is where there is insufficient torque available to meet the required torque of the torque intervention (the predicted transmission intervention torque is greater than the minimum ignition retard torque for example). In such a scenario should the engine 24 be spun up to the required transmission input shaft speed to provide the required torque then the soft-stop flag can be changed to an inactive state, the control system logic can then proceed to generate a lead actuator selection request based on the key characteristic. Therefore, the use of 10 the soft-stop flag allows for greater flexibility in the control system logic as it provides the means for the key characteristic to be met when it would not be possible using a hard stop flag. The soft-stop flag is calculated in real time by the control system 100 or an additional control system connected to control system 100. The soft-stop flag is calculated and re-calculated continuously before and / or throughout 15 the intervention. Should the stop flag change from the active state ‘1’ to the inactive state ‘0’ before or during the intervention the selection of the lead actuatorthen proceeds in the manner as described above with respect to Figure 4 or Figure 5. Otherwise, if the stop flag remains active ‘1 ’then the default actuator selection is made. Where the default lead actuator selection has been made and then subsequently the only stop flag which is a soft-stop flag changes from active ‘1 ’ to inactive ‘0’ the lead actuator selection may then restart at step S-204 and proceed down the ‘N’ branch. The resultant lead actuator request signal may over-ride any default lead actuator request signal that has been previously generated and output. Alternatively, or optionally, there may be additional control system logic which prevents the over-riding of the default lead actuator request by a later sent lead actuator request signal. The soft-stop flag is used in order to prevent confusion between which of the two actuators 24, 26 are providing the majority of the torque as part of a torque intervention which may 25 cause the torque intervention to be provided in a delayed fashion. Therefore, the soft-stop flag helps ensure the smooth delivery of the torque during a torque intervention request. An optional flow chart 400 will be described with the aid of Figure 6. Figure 6 shares a number of common features with flow chart 300. Additional steps will be described with reference to Figure 6 and flow chart 400. 30 Flow chart 400 has an optional additional step S-410 located between steps S-230 and S-240 on the ‘Y’ branch. Step S-410 is represented by a decision box with two branches ‘A’ and ‘B’. At step S-410 the control system logic determines whether to check the status of the soft-stop flag at an additional step S-420 via branch ‘A’ or to proceed to the output step S-240 via branch ‘B’. 35 Step S-420 then feeds back into step S-204 along with and the control system logic can then proceed again. At step S-410 the processor 110 can determine to proceed to step S-240 if one or more criteria are reached. For example, this may be whether the torque intervention has begun or finished therefore moving to branch 40 ‘B’ or not yet started via A’. 13 0525 Optionally, or alternatively, for example, where the soft-stop flag has been checked N times already. Where N is equal to 1,2, 3, 4, 5, 6, 7, 8, 9 or 10 or 1-10 or 1-5 or any subset or range therein of any of the values or ranges of N. This can be achieved by means of a simple counter ‘in’ increasing by 1 each time (in = in-i + 1) the control system logic passes through step S-410 and proceeds to step S-420. Once the value of in = N then 5 step S-410 proceeds to step S-240 and outputs the default lead actuator request as the lead actuator request signal, n is the number of the current iteration. At n = 1, i initially equals 0. Optionally, or alternatively, the decision at step S-410 may be made by comparing a time of a timer operated by the processor 110 one receipt of the inputs 166 at step S-210 where one of the inputs 166 is a soft-stop 10 flag. The processor 110 compares the current time since the timer started to a maximum time. When the current time is below the maximum time the decision at step S-410 will follow branch ‘A’. When the current time is equal to or greater than the maximum time the decision at step S-410 will follow route ‘B’. The maximum time may be 0.0001 to 0.1 s or 0.001 to 0.1 s or any other suitable timescale. Optionally, both the check requiring a timer and an iterative counter. In such an example the control logic 15 proceeds to step S-240 via branch ‘B’when one or both of the following criteria is reached: current time equals or is greater than the maximum time, or when i_n is equal to N. The soft-stop flag may be an incorrect intervention type flag. An incorrect intervention type flag is a flag whereby a first intervention type is requested to be carried out but in the vehicle 1 is wishing to or undertaking a second intervention type which is different to the first intervention type. This may happen where there is some overriding control logic from the processor 110 or an additional control system connected to the control system 100 which causes the incorrect intervention type flag to occur. For example, an upshift may be the requested torque intervention however, for some over-riding reason the vehicle 1 wishes to undertake a downshift instead. As a result, the soft-stop flag is raised, and the incorrect intervention type flag is active T. 25 Should the correct intervention type then occur the incorrect intervention type flag is set to inactive, ‘O’. The soft-stop flag may optionally be an insufficient torque flag. An insufficient torque flag is raised where the actuator 24 or actuator 26 is not able to provide sufficient torque required of a torque intervention. The control system 100 or other control systems connected to control system 100 may then instruct the actuator 24, 26 to 30 increase their shaft speed to provide the required torque. If this is done, then the insufficient torque flag moves from the active state ‘1 ’ to the inactive state ‘O’. The stop-flags may comprise one or more hard-stop flags and / or one or more soft-stop flags. If both a hard-stop and soft-stop flag are present and each are in an active state ‘1’ then the hard-stop flag will cause the 35 default actuator to be selected, this will occur even if the soft-stop flag is changed to an inactive state ‘O’. Similarly, if two soft-stop flags are present and only one of the two switch from an active state ‘1 ’ to an inactive state ‘0’ the presence of the remaining active ‘1’ soft-stop flag will cause the default actuator to be identified. Figures 4 to 6 illustrates methods 200, 300 and 400 described by flow charts 200, 300 and 400 according to 40 an embodiment of the invention. The methods 200, 300 and 400 is a method for controlling the lead actuator LO CXI O CO selection of a vehicle 1, such as the vehicle 1 illustrated in Figure 1 and 3. The method 200, 300 and 400 may be performed by the system 100 illustrated in Figure 3. In particular, the memory 130 may comprise computer-readable instructions which, when executed by the processor 110, perform the methods 200, 300 and 400 according to an embodiment of the invention. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A control system for outputting a lead actuator request signal for a powertrain of a vehicle with two or more actuators, the control system comprising one or more processors, the one or more processors collectively configured to:receive the following input parameters:an operational mode of the vehicle;data relating to a key characteristic of the operational mode;a torque intervention request signal;in dependence on the torque intervention request signal signalling a torque intervention: identify an actuator of the two or more actuators for providing at least part of the torque intervention in dependence on the key characteristic of the operational mode;generate a lead actuator selection request signal to request the use of the identified actuator as a lead actuator for the torque intervention; andoutput the lead actuator selection request signal, wherein the key characteristic of the operational mode comprises data relating to one or more of: an engine sound quality, a vibration and a modified torque demand.

2. The control system of claim 1, wherein the operational mode of the vehicle comprises one or both of:a transmission operating mode, anda driving operating mode comprising one or more sub-system modes indicating an operation of one or more vehicle sub-systems.

3. The control system of claim 1 or 2, wherein the input parameters comprise one or more stop flags, each of the one or more stop flags having an active state and an inactive state; andwherein when one of the one or more stop flags is in the inactive state the one or more processors are collectively configured to identify an actuator of the two or more actuators in dependence on the key characteristic of the operational mode or the use thereof.

4. The control system of claim 3, wherein the input parameters further comprise a default lead actuator identifier, the default lead actuator being the required actuator for use whilst a stop flag is in an active state; andwhen the stop flag is in the active state the one or more processors are collectively configured to identify the default lead actuator as the identified actuator.

5. The control system of claim 3 or 4, wherein, the one or more stop flags comprises one or more hard stop flags; andwherein if a hard stop flag is in the active state the hard stop flag will remain in the active state during a torque intervention indicated by the torque intervention request signal.

6. The control system of claim 5, wherein the one or more hard stop flags comprises one or more of: a20stability control intervention flag; a no gearshift flag; and hybrid system health information flag.13 05 257. The control system of any of claims 3 to 6, wherein the one or more stop flags comprises one or more soft stop flags having an active state and an inactive state; andwherein each of the soft stop flag is changeable between the active state and the inactive state during 5 a torque intervention indicated by the torque intervention request signal.

8. The control system of claim 7, wherein the one or more soft stop flags comprise one or more of: an incorrect intervention type flag; an insufficient torque flag.10 9. The control system of any proceeding claim, wherein the torque intervention request signalcomprises:a torque demand andan indication of transmission input shaft speed; andthe data relating to the key characteristic includes a prioritised lead actuator identifier, the prioritised lead 15 actuator identifier is dependent on the torque demand and the indication of transmission input shaft speed;andwherein the one or more processors are collectively configured to identify the actuator of the two or more actuators in dependence on the key characteristic of the operational mode using the prioritised lead actuator identifier.

10. The control system of claim 9, wherein the data relating to the key characteristic comprises a lookup table comprising: a plurality of prioritised lead actuator identifiers, a plurality of torque demands, and a plurality of indications of transmission input shaft speed, wherein each of the plurality of prioritised lead actuator identifiers depends on a torque demand and an indication of transmission input shaft speed pair;25 wherein the step of identifying the actuator as the actuator further comprises the step of:comparing the torque demand and the indication of transmission input shaft speed with the look-up table torque demand and indication of transmission input speed to identify an actuator as the actuator.3011. The control system of claim 4 and optionally any of claims 5 to 10, wherein the input parameters further comprising a look-up table for identifying default lead actuators;the look-up table comprising: a plurality of default lead actuator identifiers, a plurality of torque 35 demands, and a plurality of transmission input shaft speed demands, wherein each of the plurality of default lead actuator identifiers depends on a torque demand and a transmission input shaft speed demand pair; and wherein the step of identifying the default lead actuator as the actuator further comprises the step of: comparing the torque demand and transmission input shaft speed demand with the default look-up table torque demand and transmission input speed demand to identify a default lead actuator as the actuator.4012. A system comprising the control system of any preceding claim and a first actuator and a second actuator.

13. A vehicle comprising the system of claim 12 or the control system of any one of claims 1 to 10.

514. A method for outputting a lead actuator request signal for a powertrain of a vehicle with two or more actuators, the method comprising:receiving the following input parameters:an operational mode of the vehicle;10 data relating to a key characteristic of the operational mode;a torque intervention request signal;in dependence upon the torque intervention request signal signalling a torque intervention, identify an actuator of the two or more actuators in dependence on the key characteristic of the operational mode while providing at least part of the torque intervention;15 generate a lead actuator selection request signal to request the use of the actuator as a leadactuator for the torque intervention; andoutput the lead actuator selection request signal,wherein the key characteristic of the operational mode comprises data relating to one or more of: an engine sound quality, a vibration and a modified torque demand.

15. Computer readable instructions which, when executed by a computer, are arranged to perform a method according to claim 14.13 06 25

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