Vehicle, in particular a two-wheeler or three-wheeler

Abstract

The invention relates to a vehicle (10), in particular a two-wheeler or three-wheeler, comprising at least one electric motor (12) which is provided for decelerating the vehicle (10) and / or at least one vehicle wheel (14, 16) of the vehicle (10) during a braking operation, and comprising at least one vehicle battery (18) which is functionally coupled to the electric motor (12). According to the invention, the vehicle has a braking chopper unit (20) which is operatively connected to the electric motor (12) and the vehicle battery (18), has at least one braking resistor (22), and is provided for dissipating excess energy generated by the electric motor (12) during the braking operation.

Description

[0001] Description

[0002] Title especially two-wheeled or

[0003] State of the art

[0004] The invention is based on a vehicle, in particular a two-wheeled or three-wheeled vehicle, according to the preamble of claim 1. Furthermore, the invention relates to a method for operating such a vehicle.

[0005] Two-wheeled or three-wheeled vehicles, in particular motorcycles, are known from the prior art, such as DE 10 2012 209 223 A1, which comprise an electric motor and a vehicle battery functionally coupled to the electric motor. The electric motor can be used, on the one hand, to drive at least one wheel of the vehicle and, on the other hand, to decelerate at least one wheel of the vehicle. A significant advantage of electromobility is the possibility of converting the vehicle's kinetic energy into electrical energy with the help of the electric motor during braking and storing it in the vehicle battery. This process is also referred to as recuperation. However, the braking performance in this case is heavily dependent on the temperature and charge state of the vehicle battery.If the vehicle battery is too cold, too hot, or has too high a charge, it can absorb very little or no energy, meaning the electric motor cannot decelerate the vehicle wheel or can only decelerate it inadequately. In many driving situations, the vehicle battery is therefore the bottleneck for maximum braking performance, which the vehicle can implement regeneratively. Based on this, the object of the invention is, in particular, to provide a vehicle with improved properties with regard to braking functionality. This object is achieved by the features of claims 1 and 10, while advantageous embodiments and further developments of the invention can be found in the subclaims.

[0006] Disclosure of the invention

[0007] The invention is based on a vehicle with at least one electric motor, which is provided for decelerating the vehicle and / or at least one vehicle wheel of the vehicle during a braking operation, and with at least one vehicle battery, in particular in the form of an accumulator, which is functionally coupled to the electric motor.

[0008] It is proposed that the vehicle have a brake chopper unit operatively connected to the electric motor and the vehicle battery, which comprises at least one braking resistor and is designed to dissipate excess energy generated by the electric motor during braking. This configuration allows for improved braking functionality, particularly electrical braking. In particular, the availability of the braking functionality provided by the electric motor can be increased and / or advantageously reproducible regenerative braking behavior can be achieved, particularly independently of the current temperature and / or the current charge level of the vehicle battery. Furthermore, the vehicle's recuperation potential can be fully utilized.In addition, this allows for the advantageous realization of value-added functions, for example in the form of a hill start functionality, an auto-hold functionality and / or a CBS functionality.

[0009] The vehicle could, for example, be designed as a passenger car or a commercial vehicle. However, the vehicle is preferably different from a conventional passenger car or commercial vehicle. The vehicle is preferably designed as a light motor vehicle, such as a quad bike, and particularly preferably as a two-wheeled or three-wheeled vehicle, such as a moped, a motorcycle and / or a motor tricycle. Furthermore, the electric motor is operated in particular as a generator during the braking process and is provided for generating a recuperative braking torque. In this context, the electric motor is provided in particular for converting the vehicle's kinetic energy into electrical energy and transmitting it to the vehicle battery for storage in the vehicle battery. The electric motor is preferably assigned to exactly one vehicle wheel of the vehicle, advantageously a vehicle wheel designed as a rear wheel.Furthermore, the at least one vehicle wheel is preferably not assigned a hydraulic brake, for example in the form of a wheel brake cylinder, so that during the braking process the electric motor is provided exclusively for decelerating the at least one vehicle wheel. The electric motor could be designed purely as a brake motor. However, the electric motor is particularly preferably also provided for driving the vehicle and / or the at least one vehicle wheel in at least one operating state. Furthermore, the term “excess energy” should be understood to mean, in particular, energy that is generated by the electric motor during the braking process and that cannot be absorbed and / or stored by the vehicle battery, for example due to a current charge level and / or a current temperature of the vehicle battery.Furthermore, a “brake chopper unit” should be understood in particular as a functional unit which is intended to dissipate or convert into heat excess energy which arises during deceleration of the vehicle and / or of at least one vehicle wheel and in particular during the associated generator operation of the electric motor. For this purpose, the brake chopper unit comprises at least one external and / or integrated braking resistor. In addition, the brake chopper unit can comprise at least one heat sink associated with the braking resistor. In principle, the brake chopper unit can also comprise several braking resistors, for example at least two or at least three. “Provided” should be understood in particular as specially designed and / or equipped.The fact that an object is intended for a specific function should be understood in particular to mean that the object fulfills and / or performs this specific function in at least one application and / or operating state. Preferably, the brake chopper unit is arranged in terms of circuitry between the electric motor and the vehicle battery, which allows for particularly advantageously simple wiring. In this context, the vehicle can in particular comprise power electronics for controlling the electric motor. In this case, the brake chopper unit is preferably electrically connected directly to the power electronics and the vehicle battery.

[0010] The brake chopper unit can be designed to be passive and, for example, activated automatically when an operating variable, for example in the form of an intermediate circuit voltage, exceeds a certain limit value. In particular, in this case the brake chopper unit does not have a control connection for active control, for example by means of a control unit. However, it is advantageously proposed that the brake chopper unit is designed to be actively controllable. In this context, the brake chopper unit can preferably comprise at least one controllable switching unit, which can be switched by a switching and / or control signal, for example from a computing unit and / or a control unit. Furthermore, in this case the brake chopper unit can also comprise a computing unit electrically connected to the switching unit, in particular to a control connection of the switching unit, for providing the switching and / or control signal.This allows for a particularly high level of flexibility. Furthermore, corresponding value-added functions can be implemented particularly easily.

[0011] According to a further embodiment, it is proposed that at least the braking resistor be arranged in an exposed and / or well-ventilated location of the vehicle. This can improve cooling of the braking resistor and / or reduce the mass of the heat sink associated with the braking resistor.

[0012] It is also proposed that the braking resistor, in particular on or in the vehicle, be arranged in such a way that an air flow generated during a driving maneuver of the vehicle is directed toward the braking resistor. In this case, the vehicle can advantageously also comprise at least one, in particular additional, air guide element, which is designed to direct the air flow toward the braking resistor and preferably directly onto the braking resistor. This allows the thermal behavior of the braking resistor to be further optimized.

[0013] The braking resistor could, for example, be designed as a foil resistor. However, it is particularly advantageous to design the braking resistor as a wire resistor, which allows for a particularly flexible arrangement of the braking resistor on the vehicle.

[0014] It is also proposed that the vehicle comprise at least one chassis component around which the braking resistor is wound. Particularly in the case of a two-wheeled or three-wheeled vehicle, the chassis component can be, for example, a rear swing arm or a dashboard. This advantageously eliminates the need for additional mountings for the braking resistor.

[0015] It is further preferably proposed that the chassis component functions as a heat sink and is provided for cooling the braking resistor. The chassis component is preferably made of a thermally conductive material with a thermal conductivity of at least 100 W / mK, and particularly preferably of at least 200 W / mK. This advantageously eliminates the need for additional heat sinks.

[0016] A particularly high level of operational reliability can be achieved in particular if the braking resistor is arranged on the chassis component in such a way that contact, in particular by a driver, is excluded during a driving process.

[0017] Furthermore, a method for operating the aforementioned vehicle is proposed, wherein excess energy generated by the electric motor during the braking process is dissipated by means of the brake chopper unit and in particular the at least one braking resistor. This makes it possible, in particular, to achieve the advantages already mentioned, wherein at least one braking functionality can be improved. The vehicle and the method are not intended to be limited to the application and embodiment described above. In particular, the vehicle and the method can have a number of individual elements, components, and units that differs from the number stated herein to fulfill a function described herein.

[0018] Drawings

[0019] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an embodiment of the invention.

[0020] They show:

[0021] Fig. 1 shows a simplified representation of a vehicle designed as a motorcycle with an electric motor and a vehicle battery,

[0022] Fig. 2 a circuit design of the vehicle in a detailed representation and

[0023] Fig. 3 is an exemplary flowchart with main process steps of a method for operating the vehicle.

[0024] Description of the embodiment

[0025] Figure 1 shows a simplified representation of a vehicle 10 designed as a two-wheeled vehicle, by way of example. The vehicle 10 is designed as a single-track vehicle and comprises a first vehicle wheel 14 designed as the front wheel, and a second vehicle wheel 16 designed as the rear wheel. Furthermore, the vehicle 10 is designed as an electrically powered vehicle or electric vehicle. In the present case, the vehicle 10 is designed as a motorcycle, more precisely as an electric motorcycle. In principle, however, a vehicle could also be designed as a vehicle other than a motorcycle, such as a moped or a scooter. In addition, a vehicle could be designed as a three-wheeled vehicle, such as a rickshaw. Furthermore, a vehicle could also be designed as a light motor vehicle, such as a quad bike. Furthermore, a corresponding vehicle could be designed as a hybrid vehicle.

[0026] The vehicle 10 comprises an electric motor 12 and a vehicle battery 18 functionally coupled to the electric motor 12. The electric motor 12 is assigned to the second vehicle wheel 16 in the present case and is embodied, for example, as a wheel hub motor. The vehicle battery 18 is embodied as an accumulator, for example, a lithium-ion accumulator. The vehicle 10 also comprises a hydraulic braking system 26 with at least one hydraulic braking unit 28. The hydraulic braking unit 28 is assigned to the first vehicle wheel 14, while no hydraulic braking unit is assigned to the second vehicle wheel 16 in the present case. In principle, however, a hydraulic braking system could also comprise multiple braking units, with one of the braking units being assigned to each vehicle wheel. Furthermore, it is conceivable to dispense with a hydraulic braking system entirely. In addition, an electric motor could be assigned to a first vehicle wheel.Furthermore, a vehicle could comprise multiple electric motors, with one of the electric motors being assigned to each vehicle wheel. Furthermore, a vehicle could also comprise multiple vehicle batteries.

[0027] Furthermore, the vehicle 10 has at least one recuperation operating mode, in which the electric motor 12 is provided for decelerating the vehicle 10 or the second vehicle wheel 16. For this purpose, the electric motor 12 is operated as a generator during a braking operation, so that it generates a recuperative braking torque for decelerating the second vehicle wheel 16. As a result, the kinetic energy of the vehicle 10 is converted into electrical energy with the help of the electric motor 12 during the braking operation and stored, for example, in the vehicle battery 18. Furthermore, the electric motor 12 in the present case also serves to drive the vehicle 10 or the second vehicle wheel 16. For this purpose, the electric motor 12 is operated as a motor in at least one operating state that differs from the braking operation, so that it generates a drive torque for driving the second vehicle wheel 16.The electric motor 12 is thus intended, on the one hand, to decelerate the vehicle 10 and, on the other hand, to drive the vehicle 10. Alternatively, however, an electric motor could also be used exclusively to decelerate the vehicle or to drive the vehicle.

[0028] In the recuperation operating mode described above, the braking performance is generally highly dependent on the temperature and charge level of the vehicle battery 18. If the vehicle battery 18 is therefore too cold, too hot, or has an excessively high charge level, it can absorb very little or no energy, meaning that the electric motor 12 cannot decelerate the vehicle 10, or in this case the second vehicle wheel 16, or can only do so inadequately. In many driving situations, the vehicle battery 18 is therefore the bottleneck for maximum braking performance that the vehicle 10 can implement regeneratively. As a result, the regenerative braking behavior is normally very difficult to reproduce, and in many vehicles the regenerative braking torque is kept very low, so that the driver is not aware of it when the vehicle battery 18 is at an unfavorable operating point and no electrical braking power is possible.

[0029] To improve braking functionality, particularly electrical braking, the vehicle 10 in this case has a brake chopper unit 20 (see in particular Figure 2). The brake chopper unit 20 is operatively connected to the electric motor 12 and the vehicle battery 18 and is arranged in circuitry between the electric motor 12 and the vehicle battery 18. In the present case, the brake chopper unit 20 is electrically connected directly to the vehicle battery 18 on the one hand and electrically connected directly to power electronics 30 of the vehicle 10 for controlling the electric motor 12 on the other.The brake chopper unit 20 is provided to dissipate excess energy generated by the electric motor 12 during the braking process, i.e., energy generated by the electric motor 12 during the braking process and which cannot be absorbed and / or stored by the vehicle battery 18, for example, due to a current charge level and / or a current temperature of the vehicle battery 18. In the present case, the brake chopper unit 20 is designed such that, during the braking process, only the electric motor 12 is used to decelerate the vehicle 10 or the second vehicle wheel 16, and a hydraulic brake, in particular an additional one, on the second vehicle wheel 16 can be dispensed with.

[0030] For this purpose, the brake chopper unit 20 comprises at least one braking resistor 22. In the present case, the brake chopper unit 20 comprises, by way of example, precisely one braking resistor 22. The braking resistor 22 is arranged at an exposed or at least well-ventilated location of the vehicle 10. In the present case, the braking resistor 22 is arranged on the vehicle 10 or in the vehicle 10 in such a way that an air flow generated during a driving operation of the vehicle 10 is directed in the direction of the braking resistor 22, whereby cooling of the braking resistor 22 can be significantly improved. For this purpose, the vehicle 10 can, for example, comprise at least one, in particular additional, air guide element (not shown), which is designed and shaped such that an air flow is directed in the direction of the braking resistor 22 and preferably directly onto the braking resistor 22. In principle, however, such an air guide element can also be dispensed with.

[0031] In order to reduce the installation space and thus the costs of the braking resistor 22, the braking resistor 22 in this case is also designed as a wire resistor and wound directly around a chassis component 24 of the vehicle 10. The chassis component 24 functions as a heat sink and is provided for cooling the braking resistor 22, so that additional heat sinks are not necessary. In addition, the braking resistor 22 is arranged on the chassis component 24 in such a way that contact by a driver during driving is excluded. In this case, the chassis component 24 is, for example, a rear wheel swing arm of the vehicle 10. In principle, however, all chassis components with good thermal conductivity properties and for which contact during driving is excluded, in particular to avoid the risk of burns, are suitable.Alternatively, it is conceivable to design a braking resistor as a resistor different from a wire resistor, such as a foil resistor and / or a sheet resistor.

[0032] Furthermore, the brake chopper unit 20 is designed to be actively controllable. For this purpose, the brake chopper unit 20 comprises at least one controllable switching unit 32 and a computing unit 34 that interacts with the switching unit 32. Alternatively, however, a brake chopper unit can also be designed to be passive and, for example, be automatically activated when an operating variable, for example in the form of an intermediate circuit voltage, exceeds a certain limit value.

[0033] Finally, Figure 3 shows an exemplary flow chart with main process steps of a method for operating the vehicle 10.

[0034] A method step 40 corresponds to an operating state in which the vehicle 10 is in a normal driving state. The vehicle 10 can advantageously be driven by the electric motor 12. For this purpose, the electric motor 12 is operated as a motor, so that it generates a drive torque to drive the second vehicle wheel 16.

[0035] A method step 42 corresponds to a braking operation in which the vehicle 10 or the second vehicle wheel 16 is decelerated by means of the electric motor 12. For this purpose, the electric motor 12 is operated as a generator during the braking operation, so that it generates a recuperative braking torque to decelerate the second vehicle wheel 16. As a result, the kinetic energy of the vehicle 10 is converted into electrical energy during the braking operation with the aid of the electric motor 12.

[0036] In a method step 44, if possible, the energy generated by the electric motor 12 during the braking process is first stored in the vehicle battery 18.

[0037] In a method step 46, a limit of the capacity of the vehicle battery 18 is reached. In this case, the excess energy generated by the electric motor 12 during the braking process, i.e. the energy generated by the electric motor 12 during the braking process and which cannot be absorbed and / or stored by the vehicle battery 18, for example due to a current charge level and / or a current temperature of the vehicle battery 18, is dissipated by means of the brake chopper unit 20 and in particular the braking resistor 22. The exemplary flowchart in Figure 3 is intended merely to describe an example of a method for operating the vehicle 10. In particular, individual method steps can also vary, or additional method steps can be added.

Claims

Claims 1. Vehicle (10), in particular a two-wheeled or three-wheeled vehicle, with at least one electric motor (12) which is provided for decelerating the vehicle (10) and / or at least one vehicle wheel (14, 16) of the vehicle (10) during a braking process, and with at least one vehicle battery (18) functionally coupled to the electric motor (12), characterized by a brake chopper unit (20) operatively connected to the electric motor (12) and the vehicle battery (18), which comprises at least one braking resistor (22) and is provided for dissipating excess energy generated by the electric motor (12) during the braking process.

2. Vehicle (10) according to claim 1, characterized in that the brake chopper unit (20) is arranged in terms of circuitry between the electric motor (12) and the vehicle battery (18).

3. Vehicle (10) according to claim 1 or 2, characterized in that the brake chopper unit (20) is designed to be actively controllable.

4. Vehicle (10) according to one of the preceding claims, characterized in that at least the braking resistor (22) is arranged at an exposed and / or well-ventilated location of the vehicle (10).

5. Vehicle (10) according to one of the preceding claims, characterized in that the braking resistor (22) is arranged such that an airflow generated during a driving operation of the vehicle (10) is directed in the direction of the braking resistor (22).

6. Vehicle (10) according to one of the preceding claims, characterized in that the braking resistor (22) is designed as a wire resistor.

7. Vehicle (10) according to claim 6, characterized by at least one chassis component (24) around which the braking resistor (22) is wound.

8. Vehicle (10) according to claim 7, characterized in that the chassis component (24) functions as a heat sink and is provided for cooling the brake resistor (22).

9. Vehicle (10) according to claim 7 or 8, characterized in that the braking resistor (22) is arranged on the chassis component (24) in such a way that contact, in particular by a driver, during a driving operation is excluded.

10. Method for operating a vehicle (10) according to one of the preceding claims, wherein excess energy generated by the electric motor (12) during the braking process is dissipated by means of the brake chopper unit (20) and in particular the at least one braking resistor (22).

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