Vehicle and method for brake blending in a vehicle

Abstract

The present invention is related to a vehicle, in particular an electric vehicle comprising an electric powertrain, the vehicle comprising at least one energy storage unit, for storing energy for driving at least a part of the vehicle, at least one vehicle throttle control, for controlling a throttle power demand and at least a portion of a braking power demand, at least one braking system, the at least one braking system comprising a friction braking system and a regenerative braking system, configured for providing the braking power demand to the vehicle, at least one control unit, directly or indirectly communicatively connected to the at least one braking system, wherein the at least one control unit is configured for allocating, in particular dynamically allocating, at least a portion of the braking power demand. The present invention is further related to a method for brake blending in particular for a vehicle according to the invention.

Description

[0001] Vehicle and method for brake blending in a vehicle

[0002] In a regular vehicle, applying the conventional brakes via the conventional brake pedal, the friction torque or deceleration force on at least one wheel causes the vehicle to decelerate. A vehicle is defined as a movable platform with at least one wheel. A braking action usually results in friction that produces heat as a form of energy to dissipate the motion energy of the vehicle. So the kinetic energy of the vehicle is transformed into heat energy by the usually friction brake to decelerate the vehicle with a rate that feels comfortable and provides trust to the vehicle driver or vehicle controller in case no driver is present. Where in traditional vehicles such energy is usually mostly wasted, electric generators, also named electrical machines or electric motors, are typically designed with the focus on acceleration, and ability to transform this deceleration energy, or at least part of this, into electrical energy to serve other purposes. This is phenomena is called regeneration or recuperation of energy. This regeneration can, for example, also occur on a sloped road even while maintaining the same speed, so without deceleration or even with acceleration, in this case potential energy is transformed into electrical energy. So in general, regeneration is described as the energy of the vehicle that is transformed into electrical energy.

[0003] When regeneration occurs, the electrical motor, which therefore becomes an electrical generator as the torque becomes negative while the rotational speed remains positive, could reach the regeneration power limit hence the friction brake still need to be, partly, used. T o achieve this a combination of the friction brake and / or electrical generator is required and the interaction between the two devices and / or smart actuators is called brake blending. The respective brake blending strategy can depend on the generator winding temperature, and / or the generator bearing temperature, and / or any temperature measured in the powertrain, and / or a high State-of-Charge, and / or State-of-Function, and / or State-of-Power, and / or State-of- Energy, and / or State-of-Health, and / or State-of-Capacity, and / or State-of- Resistance, and / or State-of-Capacitance, and / or State-of-lnductance, and / or State- of-Open Voltage, and / or State-of-Capacitance-Energy, and / or State-of-Cell balancing, and / or State-of-Contactor, and / or State-of-Temperature, and / or State-of- Isolation, and / or State-of-Limits, and / or State-of-Diagnostics, and / or State-of- Remaining Useful Life, and / or State-of-Fall back modes, and / or State-of-Logging of one and / or multiple energy storage devices, and / or a high temperature of the power electronics inverter, and / or a high temperature in the gearbox, and / or a high temperature in the brake system, and / or a high temperature and / or status in the active suspension smart actuator, and / or a maintenance warnings, and / or a flat tyre indicator, and / or a high brake pad emission, and / or a high brake pad wear, and / or a high tyre wear, and / or a high tyre emission, and / or a detection of an object, and / or a sound indication, and / or a choice of the vehicle to use brake balancing with emphasis on another powertrain that might be present in the vehicle, and / or a contradictory command from the vehicle control unit and / or other alarms or warnings that might be present in or around the vehicle, and / or a platooning vehicle action and / or may reach the vehicle from a governing body, and / or external signal, that wants to minimize either pollution, speed, or improve traffic safety.

[0004] In an electrical vehicle with at least a single energy storage device, high energy content, high power content and high torque and speed that are transferred to at least one of the wheels is certainly advantageous, especially when they come at only slightly higher cost, cost is defined as cost to manufacture and / or cost for electricity consumption and / or cost for the environment and / or cost of maintenance and / or cost of development and / or cost of driveability, but the most troublesome issue with high acceleration and deceleration is its control, especially in deceleration brake blending is essential. As such, with high rates of acceleration, usually comes the capacity of ultra-high rates of deceleration. Even considering vehicles with limited rates of acceleration, extreme rates of deceleration will always be required in emergency and / or specific cornering and / or accident avoiding situations. In such situations even sacrificial braking that is irreversible and damages certain sacrificial components might be an option. One such possibility is to short the electrical generator to provide ultimate deceleration torque and / or use the friction brakes to extreme temperatures. In summary, brake blending implemented in a brake controller or control unit, is a controlled action of friction brake and / or electrical generator and / or a combination of friction brake and electrical generator on at least a single wheel of the vehicle in order to decelerate the vehicle to a lower speed and / or a complete vehicle standstill.

[0005] In electrical vehicle brake blending becomes ever more important as they are, until now, usually heavier than vehicle with and internal combustion engine or a combination of a combustion engine and an electrical motor to at least one of the wheels, such as a hybrid vehicle. In a battery electrical vehicle usually the first responder is the electric motor. Up to, for example, 0.3G rate of deceleration, the friction brakes will normally not even be activated. However, if more deceleration is needed, the friction brakes will account for this increase in rate of deceleration. The challenge in such situation is to achieve brake blending. As such, the mix of the two braking systems is something that still needs painstaking calibration in simulation and / or real road conditions to ensure effectiveness that the required feel that a driver and / or autonomous control unit expects from a brake request is achieved. In regards to effectiveness, current braking technology could allow to have the absolute in braking power using friction braking through advanced synthetic materials such as carbon-ceramic friction brakes. In this respect, battery electric vehicles may surely benefit from carbon-ceramic friction brakes, but their widespread adoption is still hindered by their prohibitive costs and negative impact on driving range. As such, allowing a much higher rate of deceleration that 0.3G using regeneration would be advantageous for battery electrical vehicles.

[0006] Currently brake blending is already included in certain battery electric vehicles. For example, Manufacturer 1 added brake blending via a software update, where lifting off the accelerator creates regeneration and decelerates the vehicle at a (in some cases) user-selectable degree of braking force. In case regeneration is limited, for example, with a high State-of-Charge of the battery and / or cold weather, the friction brakes are sporadically automatically applied when the throttle pedal is lifted to create the requested braking force that would normally be there on regeneration. Pushing the brake pedal always applies the friction brakes. The amount of regeneration can also be increased by the driver to increase the energy recapture in some vehicles. Numerous vehicle manufacturers that focus on one-pedal driving will lean towards a combination of stronger regeneration and friction brake when a driver lifts from the one-pedal and will solely use the brake pedal for friction. More traditional vehicle manufacturers are focused on a more traditional braking I throttle combination will include less regeneration via the throttle but try to achieve more regeneration when the brake pedal is pressed to a pre-determined level. Manufacturer 2 seems to have evermore regeneration on the throttle, and this seems to be the direction future vehicle makers will favour. A further update from manufacturer 1 has managed that the brake blending is such that it is consistent no matter the State-of-Charge or Weather. Manufacturer 3 blends regeneration and friction brake using both the brake pedal and throttle lift off cycle or sporadically both. When the driver switches the one-pedal driving mode on, regeneration is always used first before the friction brake kicks in. However, it has proven an adaptation of the driving style by the user. This is particularly due to the fact that the deceleration is not quite the same at all times, depending on the availability of regeneration capacity. When the driver switched the one-pedal driving mode off, using the brake pedal, initially regeneration is used until the driver is requesting more braking than available via regeneration, which again causes a change in deceleration behaviour. Manufacturer 4 has a regeneration behaviour that, when maximized, the vehicle will stop short of an intersection when traveling more than the speed limit and a late yellow traffic light is encountered. In the same situation, manufacturer 2, the driver has to press the friction brake to achieve a complete vehicle standstill. Manufacturer 5 the brake pedal initially actuates the regeneration and then the vehicle brake controller only activates the friction brakes when a certain threshold of brake force is exceeded that would exceed the available regeneration capacity, or to get the vehicle to come to a complete standstill. This manufacturer implemented the brake blending in such a way that at low speed regeneration seems to be paused and at elevated speed the regeneration is slowly reapplied.

[0007] Thus it is a first goal of the present invention to provide a general brake controller that allows the implementation that provides for an identical and / or substantially identical deceleration irrespective of the braking system used.

[0008] It is a second goal of the present that provides for a brake blending strategy that does not need the driver to adapt to the situation or status of the vehicle.

[0009] It is a third goal of the present invention to provide a vehicle that provides for a brake blending system which provide increased trust on the demanded deceleration of the vehicle at all time.

[0010] It is a fourth goal of the present invention to provide for an improved brake blending for providing a demanded braking power to the vehicle.

[0011] The present invention thereto proposes a vehicle, in particular an electric vehicle comprising an electric powertrain, the vehicle comprising: • at least one energy storage unit, for storing energy for driving at least a part of the vehicle,

[0012] • at least one vehicle throttle control, for controlling a throttle power demand and at least a portion of a braking power demand,

[0013] • at least one braking system, the at least one braking system comprising a friction braking system and a regenerative braking system, configured for providing the braking power demand to the vehicle,

[0014] • at least one control unit, directly or indirectly communicatively connected to the at least one braking system, wherein the at least one control unit is configured for allocating, in particular dynamically allocating, at least a portion of the braking power demand to the friction braking system and / or regenerative braking system, wherein allocating of said portion of the braking power demand is at least partially based on one or more vehicle status and / or environment status parameters.

[0015] Use of the vehicle throttle control, such as a throttle pedal, for controlling at least a portion of a braking power demand is known in the systems according to the prior art. Hence, this is typically implemented in the known regenerative braking systems, where a release of the throttle pedal triggers one of the vehicle electric motors to act as a generator to decelerate the vehicle. To this end, vehicle according to the present invention is provided with a braking system, which comprises a friction braking system and a regenerative braking system. Said braking system being arranged for providing the braking power demand to the vehicle. At least one control unit is, directly or indirectly, communicatively connected to the at least one braking system. Preferably, said control unit is furthermore, directly or indirectly, communicatively connected to the at least one vehicle throttle control. The at least one control unit may be a part of the vehicle control unit, or may be a separate independent control unit. The at least one control unit according to the present invention is preferably configured for controlling at least one brake blending strategy. The control unit is configured for allocating, in particular dynamically allocating, at least a portion of the braking power demand to the friction braking and / or regenerative braking system. Here, the at least one control unit according to the present invention may alternatively be referred to as the brake controller. Since this is based on one or more vehicle status parameters and / or one or more environment status parameters the vehicle according to the present invention is able to provide a better allocation of the braking power demand compared to the prior art. The braking power demand may be considered the input to the at least one control unit, hence the brake controller, that incorporates the brake blending strategy, where the braking power demand is preferably to be generated by the driver pushing the brake pedal and / or from a certain input from the release of the throttle pedal and / or a vehicle controller and / or any other means the brakes will be applied in the future, for example voice, joystick, etc. as a dimensionless reference Brake-ref (ranging from 0 to 1 ). The braking power demand is taken as an input by the at least one control unit which allows to ensure a consistent braking power response based on the one or more vehicle status parameters and / or the one or more environment status parameters. This may provide an increased reliability, or an increased confidence since the braking power behaves substantially similar, irrespective to which braking system the braking power demand is allocated. It is conceivable that an output force to a generator, i.e., an electric motor acting as a generator, is reduced if a braking power demand is requested in a corner. Here, the output force may for example be the portion of the braking power demand allocated to the regenerative braking system. The presence of a corner may be detected or determined by a camera, lidar, radar, a navigation tool, and / or a steering wheel angle. In respect of the present invention the term “throttle control” cannot be understood as a brake pedal. Particularly since in vehicles the throttle and break control involve different signals and the one cannot simple be replaced with the other.

[0016] Preferably, the control unit is further configured for; allocating a primary portion of the braking power demand to the regenerative braking system, and allocating a secondary portion of the braking power demand to the friction braking system, in particular wherein said secondary portion is allocated at a gradually, and preferably uninterrupted and / or smoothly, increasing and / or decreasing magnitude towards the friction braking system and / or wherein the primary portion and secondary portion are dynamically allocated. In particular the parameter that is allocated towards the friction braking system in a gradual manner is a part of the magnitude of the braking power demand. Hence, in case of gradual application of a braking power demand portion towards the friction braking system, in particularly when starting from 0 friction braking, this means the friction braking portion gradually (smoothly) goes up from no friction braking at all to the entire secondary portion being allocated. As such, the driver will not notice the friction brakes have been used, which increases comfort. By gradually increasing the magnitude of the secondary portion, i.e., a part of the braking power demand, the present invention is able to prevent noticeable intervention of the friction braking system. Preferably, the control unit is configured for allocating of a secondary portion only when allocating of a primary portion is restricted by one of the vehicle status and / or environmental status parameters. In particular the magnitude of the secondary portion is allocated gradually, and preferably smoothly, towards the friction braking system. In this respect, the allocation of the secondary portion starts with application of 0% and gradually increases towards 100% of the secondary portion. The latter may also be expressed in a dimensionless scale between 0 and 1 , wherein 0 represents no part of the secondary portion being allocated to the friction braking system, and 1 corresponding to the entire secondary portion being allocated to the friction braking system. The control unit is configured for gradually, for example by means of a continuously differentiable function, allocating the secondary portion. Hence, any value between 0% and 100% and 0 and 1 may be allocated. The value preferably increases in a way without noticeable increasing steps, hence smoothly. As a non-limitative example, the secondary portion of the braking power demand signal may be attributed to 60% of total the braking power demand. When this is determined the control unit will gradually allocate the 60% magnitude of the total the braking power demand (i.e., the so determined secondary portion) towards the friction brakes gradually. In this respect, gradually holds that not all 60% is allocated at once, but starting from 0% and gradually (preferably smoonthly) increasing towards the 60% magnitude.That is, if the primary portion is for example maximized, due to powertrain constraints such as a state of charge of the at least one energy storage unit, and a secondary portion is instantaneously allocated towards the friction braking system to fulfil the braking power demand, a sudden jump in the vehicle deceleration may be noticed at the moment the friction braking system starts to apply braking power. Therefore, it is preferred to allocate this in a gradual manner. Preferably in both increasing and decreasing direction. Allocating of a secondary portion preferably only takes place when allocating of a primary portion is restricted by one of the vehicle status and / or environmental status parameters, such as the state of charge being too high, the temperature being too high or too low, etc. for allocating more braking power towards the regenerative braking system (i.e., allocating more braking power to the primary portion). It is also imaginable that the magnitude of the secondary portion is progressively allocated towards and / or away from the friction braking system. Preferably, wherein the progressive allocation starts and / or ends with 0% friction braking allocation. In respect of the progressive allocation, the magnitude of the allocation increases or decreases exponentially. Progressive allocation may provide for a quicker application of the brake portion to the friction braking system whilst preventing a noticeable start of application. In particular the parameter that is allocated towards the friction braking system in a progressive manner is a part of the magnitude of the braking power demand. Alternatively, it is also conceivable that the control unit is configured for dynamically allocating the primary and secondary portion to the regenerative braking system and friction braking system respectively. This may in particular be beneficial to obtain a smooth and reliable vehicle deceleration based on a user braking power demand. For example, it may occur that initially a state of charge of the at least one energy storage unit allows for more storage, but during a braking action, and hence allocating of the braking power demand, in particular the primary portion thereof, towards the regenerative braking system the at least one energy storage unit may be charged beyond a threshold which reduces availability of regenerative braking power, in such an instance it may be required to reduce a magnitude of the primary portion and increasing a magnitude of the secondary portion directed to the friction braking system. However, the latter preferably again in a gradually increasing or decreasing manner. According to a preferred embodiment the control unit is configured for changing at least a portion of the braking power demand allocation from the regenerative braking system to the friction braking system if the energy storage unit is at least 85 % charged, preferably at least 90 % charged, in particular at least 95 % charged.

[0017] Preferably, the control unit is configured to determine the braking power demand at least partially based on a derivative and / or integral of at least one measured variable of the vehicle throttle control. The vehicle according to the present invention allows to use a vehicle throttle control, such as a throttle pedal, for applying a braking power. Said braking power demand preferably being at least partially based on a braking power demand signal. The braking power demand signal may for example comprise a braking magnitude, such as a braking torque. By using a derivative or integral of a measured variable of the vehicle throttle control, a more intuitive braking signal, and hence braking power may be generated. This allows the driver to apply a braking power through the vehicle throttle control in an intuitive manner, hence allowing the driver to be able to predict the braking power. This allows for an increased safety, in particular by increase of trust of the driver in the braking action that is initiated. The measured variable may in particular be a variable related to the vehicle throttle control. Hence, controlling the vehicle throttle control by a driver, such as by means of the foot of a driver, said variable changes accordingly. Preferably, the at least one derivative and / or integral of the at least one measured variable is used in addition to a vehicle throttle position, such as a pedal position. This may allow for obtaining a better braking power demand signal, which allows to apply a more intuitive or predictable braking power to at least one wheel. This may contribute to achieving a better brake blending since it may provide for more information regarding a braking desire of a driver.

[0018] In a preferred embodiment, the braking power demand is at least partially based on a braking power demand signal, wherein said braking power demand signal defines or comprises a friction braking demand (signal) and / or the regenerative braking demand (signal), in particular wherein said friction braking demand corresponds to the portion of the braking power demand allocated to the friction braking system, and wherein the regenerative braking demand corresponds to the portion of the braking power demand allocated to the regenerative braking system. It is conceivable that the braking power demand is at least partially determined and / or constructed by the control unit, it is however also conceivable that the braking power demand signal is constructed or generated elsewhere, e.g., in a cloud environment which is in communicative connection with the vehicle. This may allow to utilize more powerful calculating engines running in said cloud environment, which may provide better forecasts in optimally dividing the braking power over the friction braking and regenerative braking systems respectively. Preferable at least partially based on the vehicle status parameters and / or the vehicle throttle control output data. It is preferred that the friction braking system and the regenerative braking system may be fully independent from one another, preferably each being controlled by a single or multiple control units. When multiple control units are used, it is preferred that the control units mutually communicate to determine how to allocate the respective braking power demands. Preferably the vehicle comprises at least one high power energy storage unit, preferably wherein said high power energy storage unit forms at least a part of the at least one energy storage unit of the vehicle. This may allow for an increased regeneration of energy. It is conceivable that the at least one high power energy storage unit is a separate storage unit for electrical energy and / or a, preferably isolated, portion of the at least one energy storage unit. High power may in this application be understood as allowing high charging and discharging rates. That is, typical batteries of battery electric vehicles, or hybrid electric vehicles for that matter, comprise high energy batteries. These are typically designed to store a large amount of energy per kilogram of battery. However, these batteries are rather limited in terms of maximum charging rates. Although the charging rates are ever increasing, the typical energy storage units merely allow for a limited charging and discharging capacity, such charging and discharging rates of high energy storage units are typically limited to about 2C charging and 10C discharging. However, in particular during regenerative braking, high powers become available in a very short amount of time. These high energy peaks cannot be efficiently stored at its full capacity using regular high energy storage units. To this end, the present invention allows for more regeneration of energy using the high power energy storage unit. In particular when a vehicle requires a large deceleration, the high power energy storage may allow to store, at least temporarily, said energy for later use. Since the high power energy unit is configured for very high charging power. It is imaginable that the high power energy storage unit allows for charging and / or discharging rates of at least 50C, preferably at least 150C, more preferably at least 250C. Preferably, the control unit is configured to allocate a regenerative braking energy charging demand to the high power energy storage and / or the at least one energy storage unit based on one or more vehicle status parameters and / or one or more environment status parameters. For example, it is imaginable that if a driver quickly releases the vehicle throttle control a large braking power is demanded by a user. Typically larger braking demands cannot be fully regenerated due to restrictions in the energy storage unit. However, the present invention allows for more regeneration since the high power energy storage unit can be charged at higher rates. Therefore, the control unit may determine based upon the braking power demand to allocate at least a portion of the regenerated energy to the high power energy storage unit. This allows to regenerate more energy compared to the limited regenerative charging rate of the at least one energy storage unit. Optionally, it is imaginable that at least one high energy storage unit is configured to convert regenerative charging power into at least one different form of energy, preferably heat. For example, if the at least one high power energy storage unit is fully charged, but a large braking power demand is provided by the user, this would otherwise result in a loss of a great sum of energy. To this end, the present invention preferably comprises at least one resistor bank and / or at least one vehicle load. It is conceivable that the at least one high power energy storage unit is configured to transform the electric power regenerated into heat, for example for heating a part of the vehicle. Although this does not allow to store the regenerated energy, if e.g., the high power energy storage unit is fully charged, or almost fully charged, it does provide to still use at least a portion of the power which would have otherwise not been used. The use of the high power energy storage allows the electric motor, or electric generator if operating in regenerative mode, to respond faster due to the faster allocation possibilities of the high power energy storage. Preferably at least one high power energy storage unit is configured for charging the at least one energy storage unit, preferably the high energy storage unit. The High power energy storage unit may be configured to charge the high energy storage unit at the motor, in particular at the end of a braking phase. Preferably, the vehicle comprises at least one inverter, for converting AC power into DC power, and preferably vice versa. The inverter is preferably connected to at least one electric motor on the AC side, and to the energy storage unit on the DC side.

[0019] It is imaginable the vehicle comprises one or more bidirectional inverters. Preferably arranged to allow for both traction and regeneration. Said bidirectional inverter preferably connected to the at least one high energy storage unit and at least one electric motor. Optionally, the vehicle comprises one or more unidirectional rectifiers, arranged for regeneration of energy only and / or any combination of unidirectional rectifiers and bidirectional inverters. Preferably, said unidirectional rectifier being connected to the high power energy storage unit and at least one electric motor. This may allow the rectifier of the high power energy storage unit to be optimized for regenerative braking, which may allow for increased energy recovery. It is imaginable that the high energy storage unit is on a first high voltage rail, on which rail preferably also the one or more bidirectional inverters are connected. The high power storage unit is preferably on a second high voltage rail, on which rail preferably also the one or more rectifiers are connected. Both rails may be connected to the energy storage unit of the vehicle, which energy storage unit may comprise the high energy storage unit and the high power storage unit. Preferably, the high energy storage unit and the high power storage unit are connected via a DC / DC converter to allow the high power energy storage to charge the high energy storage unit. Yet, it is also conceivable that the high power energy storage unit and the high energy storage unit are in separate containers

[0020] Preferably, the control unit is configured for constructing the braking power demand based on one or more vehicle status parameters and / or one or more environment status parameters. In particular the control unit is configured for constructing the braking power demand based on at least one vehicle status parameters and / or one or more environment status parameters in addition to the state of charge of the energy storage unit. This may allow the control unit to determine a braking power demand based on different situations, which allows to generate a more reliable braking power demand. The driver must feel confident, irrespective of e.g., weather conditions or the state of charge of its vehicle. Therefore, it is important to allow the control unit to take into considerations these parameters. In particular weather conditions, such as rain, may significantly affect a potential maximum deceleration that may be achieved. It is imaginable that at least one the vehicle status parameter is chosen from the group of: a vehicle speed, a vehicle steering angle, a state of charge of at least one energy storage unit, a vehicle throttle control position and / or derivative and / or integral value, a vehicle energy storage unit temperature, a motor parameter, a friction brake parameter, such as a friction brake temperature, a vehicle acceleration, a vehicle deceleration, a vehicle-road contact angle. The vehicle-road contact angle may be understood as the angle of the vehicle with respect to the road, Yet, this angle of the vehicle with respect to the road may be the pitch angle of the vehicle, or the roll angle, or a combination thereof. Roll and pitch may influence contact between the road and one or more tires, and hence affect the maximum braking power of the different wheels. Preferably at least one environment status parameter is chosen from the group of; a weather condition, a road condition, a slope angle, a banking angle.

[0021] In one pedal driving and / or one throttle driving the accelerator pedal also may allow the driver to perform regenerative braking to a certain level without the need to use the brake pedal. Optimum brake blending of the friction brake and the electrical motor may provide an increased driver confidence. The combination of regeneration and friction brakes is a real engineering challenge and difficult to perform without the driver losing confidence in the rate of deceleration. Converting motion energy to electric energy and its storage in an energy storage device and vice versa is not 100% efficient. Assuming an efficiency of the energy storage unit, for example a battery, to the wheels of around 80%, then only 64% of the motion energy is captured by the regenerative braking. This leads to the concept of “coasting” or driving slow. For example, it is more energy efficient to drive slow and accelerate than to come to a complete stop and accelerate. Preferably, these vehicle status parameters are taken into account whilst determining the braking power demand. Further, for some driving conditions the best thing to do is neither to accelerate nor decelerate the vehicle. The vehicle should just roll with minimal energy usage from the energy storage. Already today at higher velocities a battery electric vehicle can be driven conveniently without having to impose an acceleration or deceleration action. Intelligent pedal control with brake blending will allow enhanced vehicle intelligence. According to the prior art, a fixed vehicle pedal angle is used as the zero position that is a boundary between the driving and the braking. The present invention preferably comprises a dynamic zero position of the vehicle throttle control. Based on the dynamic zero position that is a variable pedal angle depicting the direction switch point during pedal rotation, single pedal control can operate the driving and the braking of battery electric vehicle. Pedal torque demand is observed by a new pedal dynamics model that depicts the dynamic variation of pedal position. The model predictive control unit may determine the optimal-based energy management and / or satisfy dynamic demands and / or improve ride quality and / or ensure wheel anti-slip safety that can be used to minimize, for example, the energy consumption.

[0022] It is conceivable that the vehicle comprises a vehicle braking control, such as a braking pedal, for controlling at least a portion of the braking power demand of the vehicle. Although it is preferred that most, preferably all, of the braking is achieved through the vehicle throttle control, a brake pedal may in some instances be required e.g., via regulations or the like. Preferably, the control unit is configured for initiating both the friction braking system and the regenerative braking system based on the vehicle braking control input. This may allow a driver to press the brake pedal, whilst still being able to regenerate energy. According to a preferred embodiment the control unit is configured for dynamically allocating the braking power demand between friction braking system and regenerative braking system during the braking action, in particular based on the one or more vehicle status and / or environment status parameters. Dynamically allocating the braking power demand is preferred since it may allow to take into account changing conditions during a braking action of the driver. For example, a driver may release the vehicle throttle control, as such requesting a braking power on a portion of the road which is substantially dry, but during the deceleration of the vehicle the vehicle moves over a wet portion of the road, such as a pool of water that remained. In respect of this application, dynamically allocating the braking power demand between the friction and regenerative braking system is preferably understood as changing the application of the brake power from one wheel or vehicle side to another, or changing, based on e.g., road conditions, the allocation between the friction and regenerative system. This may significantly change the tire grip and as such may require to reallocate, that is dynamically, a portion of the braking power. It may even cause one or more wheels to block, in which case it may be conceivable that the control unit provides an alternative block and release braking action of the regenerative and / or friction braking system. Moreover, it is also conceivable that upon the start of the deceleration action an energy storage unit is not at its maximum capacity, but is charged to its maximum capacity during the deceleration. If the desired deceleration at this point is not yet achieved, it is required to reallocate a portion of the braking power towards either the friction braking system, or a resistor bank or the like. It is preferred that the one or more vehicle status parameters and / or one or more environment status parameters are monitored also during the deceleration action of the vehicle. By dynamically allocating the braking power, the vehicle according to the present invention is able to maintain the requested braking power, which increases driver confidence in the braking system. It is also conceivable that the control unit is configured for reducing a jack-knifing effect of a trailer via the dynamic allocation of the braking power demand. The later may in particular be possible if a braking system of a left side wheel, preferably both left side wheels, and right side wheel, preferably both right side wheels are independently controllable. This may allow the control unit to determine the needed braking power demand to the respective side of the vehicle, at a right frequency, in order to reduce jack-knifing. The presence of jack-knifing may be detected either by the trailer, which may communicate as such to the control unit, or by the control unit itself based on vehicle status parameters.

[0023] Preferably the control unit is configured for; primarily allocating the braking power demand to the regenerative braking system, and if the braking power demand exceeds the available regenerative braking power of the regenerative braking system, allocating a remaining portion of the braking power demand to the friction braking system. Preferably the regenerative braking power takes precedence over the friction braking power in order to regenerate more energy which could increase the range of the vehicle. To this end it is preferred that the control unit allocates the braking power demand primarily to the regenerative braking system. However, in cases where the braking power demand is larger compared to an available regenerative braking power, the deceleration of the vehicle is of utmost importance, which causes a remaining portion of the braking power demand to be allocated towards the friction braking system. However, as an alternative to allocating the remaining portion of the braking power demand to the friction braking system, it is also conceivable that regenerated energy is directed towards a resistor bank which may transform the regenerated energy that cannot be stored in the energy storage unit into, preferably usable, heat.

[0024] Preferably the friction braking system comprises at least one mechanical friction brake, such as a drum brake or disc brake, and / or at least one electrical friction brake. It is in particular preferred that a mechanical friction brake is provided in at least two wheels, preferably each wheel. It is imaginable that each of the friction brakes is independently controllable. This may contribute to the vehicle cornering performance. The control unit may, for example based on a steering wheel angle, determine to allocate a different fraction of braking power demand to at least two mechanical friction brakes. In some cases, applying a friction brake may increase the amount of energy that may be regenerated. This is in particular if an open differential is provided which simulates a slip differential. It is imaginable that the control unit is configured for pre-heating at least one friction brake. This may reduce the amount of brake particles emitted in the atmosphere upon applying the friction brakes. Similarly, pre-heating the brakes may increase the maximum braking force. The control unit may be configured to pre-heat the friction brakes if for example the at least one energy storage unit nears maximum state of charge. Such that in the event regenerative braking is not available, the friction brakes are at optimal temperature.

[0025] Preferably, the friction braking system is a brake-by-wire braking system. This may allow to map the brake pedal or throttle pedal to 100% regeneration and 0% friction brakes unless the braking is at an elevated velocity, for example 0.5m / s and or 10 rad / s of the brake pedal, in other words exceeding a predetermined threshold, to require friction blended and accomplished this without sacrificing efficiency. In general, conventional friction brake systems do not allow for 0% friction brakes, so effectively some capability is always sacrificed. A system with brake-by-wire and regeneration may be implemented in the control unit, preferably the brake controller, using a lookup table and one input, for example for the electric motor, to decide which torque request it should output to achieve a pre-determined level of deceleration.

[0026] Preferably, the regenerative braking system comprises at least one electrical generator and / or integrated generator, preferably wherein at least one generator is formed by an electric drive motor of the vehicle, and / or at least one resistor bank and / or at least one resistive element. It is in particular preferred that the vehicle comprises at least two of the aforementioned components, wherein the control unit is preferably configured to allocate regenerative braking power to any of the regenerative braking components, in particular based on one or more vehicle and / or environment status parameters.

[0027] Not mentioned yet is that in general friction brakes also have some disadvantages such as hysteresis, inaccuracy of the brake pad positioning, limited thermal feedback, not able to determine the wheel speed. Preferably, at least one electric drive motor comprises at least one sensor for determining a rotor position. Alternatively, it is preferred that the at least one electric motor is configured to determine a rotor position based on drive motor parameters. Preferably the at least one electric drive motor comprises a sensor for determining a speed and / or acceleration, and / or jerk, of the rotor, using this information also the friction brake system may benefit from the presence of the electric motor. Optionally, the control unit is configured for adjusting a magnitude of the braking power demand allocated to the regenerative braking system to simulate an engine drag torque, preferably wherein the engine drag torque is simulated upon release, in particular complete release, of the vehicle throttle control. The control unit may gradually reduce the magnitude from an initial value such as to replicate a reducing RPM of an engine by the regenerative braking system.

[0028] Preferably the vehicle, in particular the vehicle throttle control, comprises at least one feedback actuator, directly or indirectly connected to the vehicle throttle control, for providing a user feedback and / or a user reference position through the at least on vehicle throttle control. Preferably, wherein the feedback actuator is configured to provide a feedback to the user when the vehicle throttle control passes a vehicle throttle control mid position and / or, optionally dynamic, zero-position. The feedback may allow the user to experience a more natural experience, in particular in applying a braking demand through the vehicle throttle control. That is, intuitively a driver is accustomed to feeling a forced feedback in a braking pedal. Pressing the braking pedal harder means a higher feedback force through the driver’s feet is noticeable. The feedback actuator may be arranged to provide similar feedback in the throttle pedal. Especially during lifting of the pedal, and thereby generating a braking power demand, the actuator may provide for a feedback force urging the driver the feel the same as pressing a conventional brake pedal. Similar feedback is also conceivable when the vehicle throttle control is not a pedal, but a different element. By providing such a feedback force, the experience of the throttle control may be more intuitive compared to merely releasing the vehicle throttle control without receiving any form of feedback regarding the braking demand that is about to be applied.

[0029] Another form of feedback that may be rendered by such an actuator to learn a driver to drive as energy efficient as possible. To this end the actuator may position the vehicle throttle pedal in a position corresponding to the most energy efficiency, based on for example current speed, navigation instructions, upcoming corners, or the like. The driver may for example feel a small resistance, applied by the actuator, to be aware of the most energy efficient throttle control position. This allows the driver to be thought to drive more energy efficient. Additionally, said actuator may be used for driving lessons, to provide a driving student with feedback and to obtain a feeling for driving a vehicle.

[0030] Preferably the vehicle comprises at least one electric motor, for providing a driving power and / or a braking power to one or more wheels, preferably two or more wheels of the vehicle. Preferably, at least two electric motors, each for providing a driving and / or braking power to at least one wheel, wherein the control unit is configured for allocating the braking power demand to one of said electric motors based on one or more vehicle status and / or environment status parameters. Preferably, each wheel is provided with at least one electric motor. It is imaginable that if more than one electric motor is provided, at least two motors are individually controllable. In particular both in terms of throttle, as in terms of regenerative braking.

[0031] According to a different aspect, the present invention is related to a control unit for according to the present invention for controlling of a brake blending strategy according to any of the preceding claims, in particular for use in a vehicle. The invention is further related to a method for brake blending in a vehicle, in particular a vehicle according the invention, comprising the steps of:

[0032] A) Providing a vehicle throttle control, preferably according to the invention;

[0033] B) Determining a braking power demand based on a variable of the vehicle throttle control;

[0034] C) Obtaining one or more vehicle status parameters and / or one or more environment status parameters;

[0035] D) Allocating the braking power demand of step B) between a friction braking system and / or a regenerative braking system, wherein allocating of the braking power demand is based on the one or more vehicle status parameters and / or one or more environment status parameters obtained in step C). The same benefits as elucidated based on the vehicle according to the present invention apply to the method according to the present invention. It is conceivable that an output force to a generator, i.e., an electric motor acting as a generator, is reduced if a braking power demand is requested in a corner. The presence of a corner may be detected or determined by a camera, lidar, radar, a navigation tool, and / or a steering wheel angle Preferably, the method further comprises the step of:

[0036] E) Receiving an available regenerative braking power, directly or indirectly from the regenerative braking system, and preferably

[0037] F) Determining an available friction braking power based on a vehicle status and one or more friction braking system variables.

[0038] Based on an available regenerative braking power and an available friction braking power the control unit may determine an ideal allocation of the braking power demand. Yet further, it may be checked if at all the available braking power may provide the requested braking power demand. If not, it is conceivable that a warning signal is provided to a user of a vehicle. It is imaginable that step D) comprises the steps of:

[0039] D-i) allocating a primary part of the braking power demand to the regenerative braking system, and

[0040] D-ii) if the braking power demand is larger than the available regenerative braking power, allocating a secondary part of the braking power demand to the friction braking system. This may allow the braking power demand to be allocated as efficiently as possible towards the regenerative braking system without compromise of the braking power, which may increase the user confidence in the braking system. To achieve driver deceleration confidence, positive driving behaviour may be reinforced. Driving behaviour may be controlled if drivers are alerted for behaviour that results in poor energy economy. Energy consumption for both acceleration and deceleration may be tracked and monitored instantaneously rather than tracking average fuel economy for the entire trip duration. Preferably the control unit is configured to predict an instantaneous energy consumption and detection of anomalous energy economy, as being determined in the at least one control unit for the deceleration.

[0041] It is further conceivable that step D) further comprises the step of:

[0042] D-iii) if the braking power demand is larger than the combination of available regenerative braking power and the available friction braking power, applying an emergency braking system, such as a hand brake or motor lock or resistive element. This preferably being an ultimate safety measure which is only used in the case there is no braking power available in any of the systems. Providing a resistor bank may be a solution to prevent such safety measure from being initiated. In fact, if an energy storage unit of the vehicle is at maximum capacity, the regenerative braking power would normally be not significant, if possible at all. However using a resistor bank allows for directing regenerative energy to be allocated to the resistor bank instead of the energy storage unit. In said resistor bank the electric energy may be transformed into heat. Hence, although no energy is regenerated for later use, the deceleration of the vehicle may still be ascertained which is good for driver braking confidence.

[0043] Preferably, the method comprises the step of:

[0044] G) Applying the braking power, in particular the magnitude of the braking power, to at least one wheel via the regenerative braking system in an alternating pattern. Such an alternating pattern may for example be a block-type pattern, wherein at its lows no regenerative braking is applied, and the highs may correspond to a large (such as 90% of maximum capacity) regenerative braking power. Depending on the frequency of the alternating pattern an anti-block function may be established. Preferably wherein the alternating patter in is a blockpattern and / or sinusoidal pattern and / or wave pattern, wherein said alternating pattern is in particular based on a vehicle status, such as slip tire conditions. This is in particular beneficial if an electric drive motor is provided which forms a part of the regenerative braking system. This may allow the drive motor to prevent wheels from blocking under certain vehicle conditions. Normally, this is implemented through the vehicle friction brakes which in an alternating pattern clamp and release to prevent wheels from being blocked. However, electric drive motors are able to switch at a significantly higher frequency compared to friction brakes, which makes the antiblock function according to the present invention more efficient. Preferably, during step D) the braking power demand is allocated towards the regenerative braking system and / or friction braking system for controlling at least one vehicle slip, preferably a vehicle acceleration and / or deceleration and / or cornering slip and / or vehicle angle. This may be performed by monitoring and / or measuring a wheel speed. Monitoring or measuring the wheel speed may be based on sensors, or data from at least one electric motor. Said wheel speed data may be compared with at least one vehicle status parameter, such as vehicle speed, in order to determine a vehicles slip. If the wheel speed for example does not correspond to a predetermined current vehicle speed, this may mean that at least one wheel is spinning. In an extreme scenario a wheel speed is measured by the electric motor, but a current vehicle speed is still 0 km / h or at least close to 0 km / h, this means that at least one wheel is spinning, which obviously is not desired. The same may occur when decelerating. If for example the vehicle speed is still relatively high, such as 120 km / h, or 100 km / h, or about 50 km / h, but a measured wheel speed is already equal to zero, this means a wheel is blocked. A blocked wheel that slips with respect to the road does not provide the demanded deceleration of the braking power demand. Hence, appropriate action is required, such as by an alternating block pattern as explained above.

[0045] Optionally during step D) at least a portion of the braking power demand is allocated, directly or indirectly, to at least one resistive element and / or at least one capacitive element and / or at least one inductive element if based on the one or more vehicle status parameters and / or one or more environment status parameters obtained in step C), such as a vehicle battery state of charge or battery status. That is, a state of charge of the vehicle energy storage unit may prevent further charging thereof. Since it may be required to provide a deceleration, and friction brakes may be at a temperature which is not suitable to provide said deceleration, it is conceivable that at least a portion of the braking power is, via electricity regenerated by the regenerative braking system, routed towards the capacitive element to store said energy temporarily. This may be used at a later point in time if e.g., a large acceleration is demanded. It is also possible that during step D) at least a portion of the braking power demand is allocated to a heat generating component, such as a resistor, and wherein at least a portion of generated heat is used for heating a component of the vehicle, such as a battery and / or seat and / or window and / or preheating of a friction brake. According to a preferred embodiment it is possible that if a position variation of the vehicle throttle control varies above a predetermined speed, it is configured to operate as a partial differential lock.

[0046] The present invention will hereinafter be further elucidated based on the following non-limitative figures, wherein:

[0047] - Figure 1 shows a non-limitative embodiment of a vehicle according to the present invention;

[0048] - Figures 2a-2c show different configurations of a part of the vehicle according to the present invention; and

[0049] - Figure 3 shows a non-limitative embodiment of the method according to the present invention.

[0050] Figure 1 shows a schematic non-limitative embodiment of the vehicle 100 according to the present invention. The vehicle 100 comprises four wheels 109, wherein each wheel is provided with an electric motor 107. However, it may also be the case that not every wheel 109 is provided with an individual motor 107. For example, it is imaginable that the vehicle comprises a front motor and a rear motor, for powering respectively the front wheels 109 and rear wheels 109. Yet it is also imaginable that the vehicle comprises only a motor driving the front or rear wheels 109 none of said drive configurations are excluded. However, it is believed that optimum results may be achieved if each wheel 109 is provided with an individual motor 107, or if each wheel may be individually powered by means of the aforementioned front and rear motor. In this embodiment, the front wheels 109 are provided with a friction brake 108, forming the friction braking system 108 of the vehicle . In order to provide a torque to the wheels 109 via the motors 107, each motor is connected to a vehicle storage unit 101. In particular, the vehicle storage unit 101 is connected to a inverter 111 , which in turn is connected to the motor 107. The inverter 111 allows for inverting the DC current from the vehicle storage unit 101 into AC current, such as 3-phase AC current, for the motors 107 according to a requested torque input. When the vehicle 100 is decelerating, the motors 107 may generate AC current, which via inverter 111 may be inverted into DC current such as to allow the vehicle storage unit 101 to be charged. The latter is typically referred to as regenerative braking. A driver of the vehicle uses the vehicle throttle control 104, which may be a throttle pedal 104, and optionally the vehicle brake pedal 105 to control the speed of the vehicle 100. The vehicle may allow for one pedal driving. That is, the vehicle 100 may be driven essentially exclusively by operating the vehicle throttle control 104, preferably the vehicle brake pedal 105 is merely used in emergency situations. The vehicle throttle control 104 may directly or indirectly provide input to the vehicle control unit 110. The vehicle control unit 110 allows for determining a requested torque output based on the input received from the vehicle throttle control 104. Hence, releasing the throttle pedal 104 may correspond to a certain deceleration request, which in turn corresponds to a specific negative torque request in the case regenerative braking is used, or a specific friction braking force. In order to allow the control unit 110 to provide the requested deceleration, the control unit 110 is communicatively connected to the braking system of the vehicle 100, which in this embodiment is formed by the friction brakes 108, and the electric motors which may operate as generators. The friction brakes 108 may be controlled by the control unit 110 via a brake-by-wire system, whereas the motors may be controlled by the control unit 110 via e.g., the inverters 111. The control unit 110 may be communicatively connected 112 to one or more drivetrain components, such as the energy storage unit 101 , or the inverter 111 in order to receive one or more vehicle status parameters. The examples given in this figure are merely illustrative, the skilled person would realize that more and different types of vehicle status parameters may be communicated to the vehicle control unit 110. Additionally, it is imaginable that the vehicle control unit 110 receives one or more environment status parameters. The latter parameters may be received via an internet connection, or via camera’s, or the like. The vehicle throttle control 104 may allow the driver to provide a braking power demand (for example by partially releasing the throttle pedal 104). The control unit 110 receiving the braking power demand will allocate said braking power demand to the wheels 109. However, since the vehicle 100 comprises both a friction braking system and a regenerative braking system, the allocation of the braking power demand should be smart. To this end, the control unit 110 allocates, in particular dynamically, the braking power demand to the regenerative braking system (in this embodiment formed by the electric motors 107) and the friction braking system (in this embodiment formed by the friction brakes 108). Allocating occurs on the basis of one or more drivetrain status parameters and / or one or more environment status parameters, which the control unit 110 receives. Preferably, the control unit 110 primarily allocates the braking power demand towards the regenerative braking system, since this may allow to regenerate a portion of the (kinetic) energy of the vehicle 100 into (electric) energy to be stored in the energy storage unit 101 of the vehicle 100. The vehicle 100 according to the present invention further comprises a high power battery 103 and a high energy battery 102. This contributes significantly to optimizing the brake blending strategy of the control unit 110. For example, when the braking power demand corresponds to a large deceleration, the control unit is configured to primarily allocate the braking power towards the regenerative braking system 107. However, the regenerative braking system is limited to the charging capacity and the state of charge of the energy storage unit 101 of the vehicle 100. The high energy battery 102 which is normally installed in vehicles 100 may allow for storing large amounts of energy, such as to allow the vehicle to have a larger range. However, these high energy batteries 102 typically have a restriction as to the charging capacity thereof. The high power batteries 103 allow for significantly larger charging rates. Hence, the braking power demand may primarily be allocated towards the regenerative braking system 107. Due to the high power energy storage unit 103 a significantly larger amount of (kinetic) energy may be recovered. Not only that, it also contributes to the confidence to a driver of the braking power, since it may allow the vehicle 100 to provide the braking power demand with both regenerative 107 and friction brakes 108. It is imaginable that the control unit 110 determines whether to allocate the regenerated energy to either the high energy storage unit 102 or the high power storage unit 103. However, the latter may alternatively be determined by the inverter 111. Although the control unit 110 is depicted as a distinct component, it is imaginable that the control unit 110 is part of at least one inverter 111.

[0051] In figures 2a-2c different conceivable configurations of the drivetrain of the vehicle are depicted. Figure 2a shows a primary configuration. At least one electric motor 107 is connected to an inverter 111 , said inverter 111 configured for inverting the three-phase AC power into DC power, which may charge an energy storage unit 101 . In this embodiment the inverter 111 , in particular the DC side of the inverter, is connected electrically to a high power energy storage unit 103. The high power energy storage unit 103 is also connected to a further inverter 115, which is preferably of the type DC / DC. The DC / DC inverter 115 is further connected to a high energy storage unit 102. The first inverter, of the type AC / DC, is depicted to be communicatively connected 112 to the control unit 110, however the control unit 110 may also be connected otherwise as long as it is able to control the flows of power. This embodiment is advantageous since it may allow to regenerate more energy, moreover it is possible to achieve greater deceleration rates using this configuration. The latter is possible since the high power energy storage unit 103 allows for significantly larger charging rates. These large charging rates may occur during braking of the vehicle. However, since the energy storage of the high power energy storage unit 103 is typically limited, at least too low for providing an acceptable range to the vehicle, a further energy storage unit of the high energy type 102 is provided. However, the output power of the high power energy storage unit 103 does not match the charging rates of the high energy storage unit 102, which is why a DC / DC converter is arranged. Hence, as such it is possible to, based on the braking power demand, allocate possibly the entire braking power demand towards the regenerative braking system 107, which may even recuperate essentially all energy (except for system losses) from the deceleration due to the high charging capacity of the high power energy storage unit 103. After the deceleration is finished, the high power energy storage unit may gradually charge, that is via DC / DC inverter 115, the high energy storage unit 102 such as to be prepared for an upcoming braking power demand of the driver. It is imaginable that two consecutive braking power demands of the driver follow close to one another, and the high power energy storage unit 103 is not fully discharged and hance not able to receive all energy from the deceleration. To this end, it is imaginable that a resistive element 113 and a load element 114 are provided. In this embodiment both resistive element and load element 114 are connected to the DC-line from the first inverter 111. The resistive element 113 may for example be a resistor bank 113 configured for transforming electric energy received from the inverter 111 into heat. Typically, the control unit 110 is configured to allocate the regenerative braking energy towards the resistive element 113 in case the high power energy storage unit 103 is fully charged. Additionally, it is also imaginable that instead, or in addition to, the resistive element 113 the load element 114 is used to dissipate the excess of power that cannot be stored in the high power energy storage unit 103 during the deceleration. Since the control unit is configured to dynamically allocate the braking power demand, it is conceivable that during the deceleration the maximum state of charge of the high power energy storage unit 103 is reached, and in reaction to reaching said state of charge the regenerated power is allocated to the resistor bank 113, where heat is generated which may be utilized in other parts of the vehicle, such as in seat heating. Figure 2b shows a different configuration. Although this configuration shares a large number of components, which are indicated by use of the same reference number, some differences are present. First, instead of the more linear configuration of figure 2a, this configuration may be conceived as more parallel. The regenerative braking system 107 is connected to two inverters 111 , wherein each inverter 111 is connected on its DC- side to a high energy storage unit 102 and high power storage unit 103 respectively. The first inverter 111 is connected via a DC high voltage rail 116 to the high energy storage unit 102, whereas the other inverter 111 is connected via a DC high voltage rail 117 to the high power energy storage unit 103. The high energy storage unit 102 and high power storage unit are mutually connected through a DC / DC inverter 115, similar to figure 2a. However, the benefit of this configuration is that it is not required for the regenerated energy to always be allocated to the high power storage unit 103 primarily. This may allow for more flexibility, and possible less system losses. If, for example, the braking power demand corresponds to a very low deceleration request, it may be more efficient to allocate the power to the high energy storage unit 102 directly, instead of requiring the power to be routed to an inverter 111 , a high power storage 103, and a further inverter 115, before being able to charge the high energy storage 102. Preferably, the control unit 110 is configured for allocating the regenerated energy to the high energy storage unit 102 and / or high power storage unit 103 based on the magnitude of the braking power demand, and optionally additional parameters. The control unit 110 is additionally communicatively connected 112 to the friction braking system 108, which is preferably only used when absolutely necessary. The resistive element 113 and load element 114 as discussed in figure 2a are each connected to the first DC high voltage rail 116. However, it is also conceivable that said resistive element 113 and load element 114 are connected to the second DC high voltage rail 117. Figure 2c is to a large extend similar compared to figure 2b. However, the connection of the resistive element 113 and the load element 114 is different. Here, the high power storage unit 103, the high energy storage unit 102, and both the resistive element 113 and load element 104 are all connected to a DC / DC / DC / DC inverter 111 , comprising four DC outputs. Where routing of power towards the resistive element 113 (or load element 114 for that matter) in figure 2a and 2b is limited to the power on the DC high voltage line 116, 117, the inverter 115 may allow for routing variable power to said resistive element 113 and load element 114. This may provide for more flexibility in terms of optimizing the allocation of the braking power demand by the control unit 110 (not shown in this configuration). All aspects of the shown configurations may be combined. These configurations contribute to a more flexible allocation of regenerative braking power, allowing the regenerative braking to be blended in in a less noticeable manner to the driver. In addition, the shown configurations allow for increased braking power using regenerative braking. As such, a more robust and more trustworthy brake blending may be realized.

[0052] Figure 3 shows a non-limitative flow according to an embodiment of the method 200 according to the invention. A driver may provide a braking power demand 201 , which may for example be provided upon a release of the vehicle throttle pedal. The braking power demand 201 is received by the control unit 202 of the vehicle. The vehicle control unit 202 further receives one or more vehicle status parameters 204 and / or one or more environment status parameters 203. The control unit is configured to determine a braking strategy based on said vehicle status parameter 204 and / or environment status parameter 203. The braking strategy comprises a predetermined allocation, preferably dynamic allocation, of the braking power demand to the friction braking system 206 and / or regenerative braking system 205. If, for example, the available regenerative braking power, which may for example be indicated by an energy storage unit 209 and / or electric motor 207 of the vehicle, is larger than the braking power demand, the braking power demand is preferably fully allocated to the regenerative braking system 205 in order to retain the most energy, whilst ensuring the requested deceleration is delivered. This may contribute to the driver confidence in the braking system. It may be conceivable that the state of charge of the energy storage unit 209 does not allow for fully receiving the potential energy of the deceleration governed by the braking power demand. In this case, it is imaginable that, upon reaching a predetermined state of charge of the energy storage unit 209, for example 95%, the remainder of the regenerated energy is allocated towards a resistive element 208 which may transform the regenerated energy into (usable) heat. Alternatively, the control unit 202 may allocate a portion of the braking power demand towards the friction braking system 206, if not all of the energy of the braking power demand may be stored in the energy storage unit 209.

[0053] Where it is noted that components are communicatively connected to each other, it must be understood that this may be both wired as well as wireless. Components may for example allow for communication through Bluetooth, CAN-lines and / or other communication channels. The above-described inventive concepts are illustrated by several illustrative embodiments. It is conceivable that individual inventive concepts, including inventive details, may be applied without, in so doing, also applying other details of the described embodiments. It is not necessary to elaborate on examples of all conceivable combinations of the above-described inventive concepts, as a person skilled in the art will understand numerous inventive concepts can be (re)combined in order to arrive at a specific application and / or alternative embodiment.

[0054] The ordinal numbers used in this document, like “first”, “second”, and “third” are used only for identification purposes. Hence, the use of expressions like a “second” component, does therefore not necessarily require the co-presence of a “first” component. By "complementary" components is meant that these components are configured to co-act with each other. However, to this end, these components do not necessarily have to have complementary forms. The verb “comprise” and conjugations thereof used in this patent publication are understood to mean not only “comprise”, but are also understood to mean the phrases “contain”, “substantially consist of”, “formed by” and conjugations thereof.

Claims

Claims1 . A vehicle, in particular an electric vehicle comprising an electric powertrain, the vehicle comprising:• at least one energy storage unit, for storing energy for driving at least a part of the vehicle,• at least one vehicle throttle control, for controlling a throttle power demand and at least a portion of a braking power demand,• at least one braking system, the at least one braking system comprising a friction braking system and a regenerative braking system, configured for providing the braking power demand to the vehicle,• at least one control unit, directly or indirectly communicatively connected to the at least one braking system, wherein the at least one control unit is configured for allocating, in particular dynamically allocating, at least a portion of the braking power demand to the friction braking system and / or regenerative braking system, wherein allocating of said portion of the braking power demand is at least partially based on one or more vehicle status and / or environment status parameters.

2. Vehicle according to claim 1 , wherein the control unit is further configured for;- allocating a primary portion of the braking power demand to the regenerative braking system, and- allocating a secondary portion of the braking power demand to the friction braking system, wherein said secondary portion is allocated at a gradually, and preferably uninterrupted, increasing magnitude towards the friction braking system.

3. Vehicle according to claim 2, wherein the magnitude of the secondary portion is progressively, and preferably smoothly, allocated towards the friction braking system.

4. Vehicle according to any of the preceding claims, wherein the control unit is configured to determine the braking power demand at least partially basedon a derivative and / or integral of at least one measured variable of the vehicle throttle control.

5. Vehicle according to any of the preceding claims, wherein the braking power demand is at least partially based on a braking power demand signal, wherein said braking power demand signal defines or comprises a friction braking demand and / or the regenerative braking demand, in particular wherein said friction braking demand corresponds to the portion of the braking power demand allocated to the friction braking system, and wherein the regenerative braking demand corresponds to the portion of the braking power demand allocated to the regenerative braking system.

6. Vehicle according to any of the preceding claims, wherein the vehicle comprises at least one high power energy storage unit, preferably wherein said high power energy storage unit forms at least a part of the at least one energy storage unit of the vehicle.

7. Vehicle according to claim 6, wherein the high power energy storage unit is configured for charging and / or discharging at rates of at least 50C, preferably at least 150C, more preferably at least 250C.

8. Vehicle according to any of the preceding claims, wherein the control unit is configured for constructing the braking power demand based on one or more vehicle status parameters and / or one or more environment status parameters.

9. Vehicle according to claim 8, wherein at least one the vehicle status parameter is chosen from the group of: a vehicle speed, a vehicle steering angle, a state of charge of at least one energy storage unit, a vehicle throttle control position and / or derivative and / or integral value, a vehicle energy storage unit temperature, a motor parameter, a friction brake parameter, such as a friction brake temperature, a vehicle acceleration, a vehicle deceleration, a vehicle-road contact angle.

10. Vehicle according to claim 8 or 9, wherein at least one environment status parameter is chosen from the group of; a weather condition, a road condition, a slope angle, a banking angle.11 . Vehicle according to any of the preceding claims, wherein the vehicle comprises a vehicle braking control, such as a braking pedal, for controlling at least a portion of the braking power demand of the vehicle.

12. Vehicle according to claim 11 , wherein the control unit is configured for initiating both the friction braking system and the regenerative braking system based on the vehicle braking control input.

13. Vehicle according to any of the preceding claims, wherein the control unit is configured for dynamically allocating the braking power demand between friction braking system and regenerative braking system during the braking action, in particular based on the one or more vehicle status and / or environment status parameters.

14. Vehicle according to claim 13, wherein the control unit is configured for;- primarily allocating the braking power demand to the regenerative braking system, and- if the braking power demand exceeds the available regenerative braking power of the regenerative braking system, allocating a remaining portion of the braking power demand to the friction braking system.

15. Vehicle according to any of the preceding claims, wherein the friction braking system comprises at least one mechanical friction brake, such as a drum brake or disc brake, and / or at least one electrical friction brake.

16. Vehicle according to any of the preceding claims, wherein the regenerative braking system comprises at least one electrical generator and / or integrated generator, preferably wherein at least one generator is formed by an electric drive motor of the vehicle, and / or at least one resistor bank and / or at least one resistive element.

17. Vehicle according to any of the preceding claims, wherein the control unit is configured for adjusting a magnitude of the braking power demand allocated to the regenerative braking system to simulate an engine drag torque, preferably wherein the engine drag torque is simulated upon release of the vehicle throttle control.

18. Vehicle according to any of the preceding claims, wherein the control unit is configured for changing at least a portion of the braking power demand allocation from the regenerative braking system to the friction braking system if the energy storage unit is at least 85 % charged, preferably at least 90 % charged, in particular at least 95 % charged.

19. Vehicle according to any of the preceding claims, further comprising;- at least one electric motor, for providing a driving power and / or a braking power to one or more wheels, preferably two or more wheels of the vehicle.

20. Vehicle according to any of the preceding claims, comprising at least two electric motors, each for providing a driving and / or braking power to at least one wheel, wherein the control unit is configured for allocating the braking power demand to one of said electric motors based on one or more vehicle status and / or environment status parameters.21 . Method for brake blending in a vehicle, in particular a vehicle according to any of the claims 1 -20, comprising the steps of:A) Providing a vehicle throttle control, preferably according to any of the claims 1 -30;B) Determining a braking power demand based on a variable of the vehicle throttle control;C) Obtaining one or more vehicle status parameters and / or one or more environment status parameters;D) Allocating the braking power demand of step B) between a friction braking system and / or a regenerative braking system, wherein allocating of the braking power demand is based on the one or more vehicle status parameters and / or one or more environment status parameters obtained in step C).

22. Method according to claim 21 , further comprising the step of:E) Receiving an available regenerative braking power, directly or indirectly from the regenerative braking system, and preferablyF) Determining an available friction braking power based on a vehicle status and one or more friction braking system variables.

23. Method according to claim 22, wherein step D) comprises the steps of: D-i) allocating a primary part of the braking power demand to the regenerative braking system, andD-ii) if the braking power demand is larger than the available regenerative braking power, allocating a secondary part of the braking power demand to the friction braking system.

24. Method according to claim 23, wherein step D) further comprises the step of:D-iii) if the braking power demand is larger than the combination of available regenerative braking power and the available friction braking power, applying an emergency braking system, such as a hand brake or motor lock or resistive element.

25. Method according to any of the claims 21-24, comprising the step of:G) Applying the braking power, in particular the magnitude of the braking power, to at least one wheel via the regenerative braking system in an alternating pattern.

26. Method according to claim 25, wherein the alternating patter in is a blockpattern and / or sinusoidal pattern and / or wave pattern, wherein said alternating pattern is in particular based on a vehicle status, such as slip tire conditions.

27. Method according to any of the claims 21-26, wherein during step D) the braking power demand is allocated towards the regenerative braking system and / or friction braking system for controlling at least one vehicle slip, preferably a vehicle acceleration and / or deceleration and / or cornering slip and / or vehicle angle.

28. Method according to any of the claims 21-27, wherein during step D) at least a portion of the braking power demand is allocated, directly or indirectly, toat least one resistive element and / or at least one capacitive element and / or at least one inductive element if based on the one or more vehicle status parameters and / or one or more environment status parameters obtained in step C), such as a vehicle battery state of charge or battery status.

29. Method according to any of the claims 21-28, wherein during step D) at least a portion of the braking power demand is allocated to a heat generating component, such as a resistor, and wherein at least a portion of generated heat is used for heating a component of the vehicle, such as a battery and / or seat and / or window and / or pre-heating of a friction brake.

30. Method according to any of the claims 21-29, wherein if a position variation of the vehicle throttle control varies above a predetermined speed, it is configured to operate as a partial differential lock.

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