POWER CONTROL DEVICE FOR CONTROLLING AN ELECTRIC MACHINE IN A VEHICLE TRAILER

Abstract

A power control device is provided for controlling an electric machine in a vehicle trailer. The electric machine is coupled to at least one wheel of the vehicle trailer to be able to convert mechanical rotation power at the wheel and electric power at the electric machine into one another. The power control device is configured to control a mechanical power output and/or a mechanical power input of the electric machine and is configured to control the mechanical power output and/or the mechanical power input of the electric machine as a function of a present driving condition of a towing vehicle pulling the vehicle trailer.

Claims

1-10. (canceled)

11. A power control device for controlling an electric machine in a vehicle trailer, the electric machine being coupled to at least one wheel of the vehicle trailer to be able to convert mechanical rotation power at the wheel and electric power at the electric machine into one another, the power device configured to: control a mechanical power output of the electric machine and/or a mechanical power input of the electric machine; and control the mechanical power output of the electric machine and/or the mechanical power input of the electric machine as a function of a present driving condition of a towing vehicle pulling the vehicle trailer.

12. The power control device as recited in claim 11, wherein the vehicle trailer includes a drawbar for attachment to the towing vehicle and for transmitting forces between the towing vehicle and the vehicle trailer, and wherein the power control device includes an electromechanical sensor system configured to generate a control signal for controlling the mechanical power output of the electric machine and/or the mechanical power input of the electric machine as a function of a force presently transmitted by the drawbar or as a function of a present relative distance between the towing vehicle and the vehicle trailer.

13. The power control device as recited in claim 12, wherein a deflection lever is provided at the drawbar, which is displaced into various orientations as a function of a relative distance between the towing vehicle and the vehicle trailer, the sensor system configured to generate the sensor signal as a function of a present orientation of the deflection lever.

14. The power control device as recited in claim 13, wherein a force transmission unit engages at the deflection lever, which causes a force on a brake of the vehicle trailer as a function of an orientation of the deflection lever, using which a braking force caused by the brake is controlled.

15. The power control device as recited in claim 14, wherein the force transmission unit is configured in such a way that in the event of a run of the vehicle trailer toward the towing vehicle, the braking force caused by the brake is generated only when the deflection lever has been reoriented at least by a minimum orientation angle, and the sensor system is configured to generate the sensor signal as a function of the present orientation of the deflection lever at orientation angles less than the minimum orientation angle.

16. The power control device as recited in claim 14, wherein a damping element is situated between the deflection lever and the force transmission unit, which transmits a force in a damped manner between the deflection lever and the force transmission unit.

17. The power control device as recited in claim 10, wherein the power control device includes a data interface via which control signals are to be received, which are generated in the towing vehicle and which specify a piece of information about the present driving condition.

18. The power control device as recited in claim 17, wherein the power control device includes a transmitter configured to be coupled in the towing vehicle to a vehicle control unit and which generates the information about the present driving condition based on signals from the vehicle control unit and transmits it to the data interface of the power control device.

19. The power control device as recited in claim 18, wherein the vehicle control unit is configured to generate a brake actuation signal.

20. The power control device as recited in claim 10, wherein the power control device is configured to control the mechanical power output of the electric machine and/or the mechanical power input of the electric machine, as a function of GPS data and/or navigation data relating to a route of the vehicle trailer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Specific embodiments of the present invention are described hereinafter with reference to the figures, with neither the figures nor the description to be interpreted as restricting the present invention.

[0022] FIG. 1 shows a vehicle combination including a towing vehicle and a vehicle trailer including a power control device according to one specific example embodiment of the present invention.

[0023] FIG. 2 shows components of a vehicle trailer including a power control device provided thereon according to one specific example embodiment of the present invention.

[0024] FIG. 3 shows components of a vehicle trailer having an alternative power control device provided thereon according to a further specific example embodiment of the present invention.

[0025] The figures are solely schematic and are not true to scale. Identical reference numerals identify identical or identically-acting features in the figures.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0026] FIG. 1 shows a vehicle combination 1 including a towing vehicle 3 and a vehicle trailer 5. Vehicle trailer 5 is coupled via a drawbar 7 to towing vehicle 3. An electric machine 9 is provided in vehicle trailer 5, which is mechanically coupled to at least one wheel 11 of vehicle trailer 5 to convert rotation power at wheel 11 into electric power in a recuperating manner or vice versa to drive wheel 11 by inputting electric power. Recuperated energy may be stored, for example, in an energy accumulator 10 such as a lithium-ion battery packet and may be withdrawn from it again as needed.

[0027] Electric machine 9 is controlled with respect to its power input or power output by a power control device 13. According to an example embodiment of the present invention, the control of electric machine 9 takes place in consideration of a present driving condition of towing vehicle 3. Various measures may be implemented to obtain a piece of information about the present driving condition of towing vehicle 3.

[0028] In a first embodiment of the present invention, drawbar 7 may be modified to obtain a piece of information relating to a relative position between towing vehicle 3 and trailer 5 or to obtain a piece of information relating to forces transmitted between these two.

[0029] For this purpose, as shown in FIGS. 2 and 3, a deflection lever 15 may be provided at drawbar 7, which is pivoted during the run of trailer 5 toward towing vehicle 3, due to the change accompanying this of a present relative distance between towing vehicle 3 and trailer 5, and thus changes its orientation, as illustrated by arrow 17. A sensor system 19 is provided at deflection lever 15, which generates a sensor signal as a function of a present orientation of deflection lever 15 and transmits it, preferably wirelessly, to a data interface 21 of power control device 13. The sensor signal thus specifies, for example, how intensely trailer 5 is running toward towing vehicle 3 upon braking of towing vehicle 3 and is thus a measure of presently transmitted drag forces or thrust forces or a present relative distance between towing vehicle 3 and trailer 5.

[0030] Deflection lever 15 may be part of a braking system of trailer 5. During the run of trailer 5 toward towing vehicle 3, deflection lever 15 actuates a force transmission unit 23, for example, in the form of a brake cable 27, so that a force is caused on a brake 25 of a trailer 5 as a function of an orientation of deflection lever 15, with the aid of which the braking force of brake 25 is controlled.

[0031] Force transmission unit 23 may be configured here in such a way that deflection lever 15 initially has to be moved by a minimum orientation angle before force transmission unit 23 causes a braking force at brake 25. For example, brake cable 27 may be slightly loose, so that deflection lever 15 initially has to overcome a play before brake cable 27 is tensioned. Sensor system 19 may also detect orientation changes of deflection lever 15 which are less than the minimum orientation angle. Therefore, based on sensor signals of sensor system 19, power control device 13 may already activate electric machine 9 for recuperation before trailer 5 has significantly run toward towing vehicle 3 and in particular before brakes 25 of trailer 5 are activated. Kinetic energy of trailer 5 may thus be recuperated very efficiently.

[0032] In the example partially shown in FIG. 3, a damping element 29 is additionally situated between deflection lever 15 and brake cable 27 acting as force transmission unit 23. Due to damping element 29, on the one hand, a mechanical connection may always be provided without play between deflection lever 15 and brake cable 27 and thus mechanical brake 25 may engage instantaneously, for example, in the event of a failure of the electrical system in trailer 5. On the other hand, deflection lever 15 may be slightly pivoted during slowly beginning decelerations of towing vehicle 3 without this immediately resulting in an actuation of brake 25, so that the reorientation of deflection lever 15 is detected by sensor system 19 and the sensor signal generated thereupon may be used for the control of the recuperation by power control device 13.

[0033] In an alternative embodiment of the present invention, as indicated in FIG. 1, data interface 21 of power control device 13 communicates with a transmitter 31 in towing vehicle 3. Transmitter 31 is coupled to a vehicle control unit 33. Vehicle control unit 33 generates signals, for example, a brake actuation signal, on the basis of which the present driving condition of towing vehicle 3 may be inferred. On the basis of such signals, transmitter 31 may transmit suitable pieces of information to power control device 13, so that it may control the power input or power output of electric machine 9 correctly for the situation.

[0034] Designs of possible specific embodiments of the present invention are explained once again hereinafter with partially different wording.

[0035] Vehicle trailers 5 such as camper trailers having luxury equipment usually have a separate 12 V battery. This battery is used to supply electrical consumers in the decoupled state independently of the towing vehicle and overhead power, i.e., within the scope of on autonomous energy supply. These consumers are usually comfort consumers such as lighting and water pumps, but also movers for parking the trailer. Camper trailers are conventionally supplied with electric energy from towing vehicle 3 while driving and the battery is recharged. Solar cells are also used to assist recharging the battery. Typically, 12 V lead accumulators are used as batteries. The energy content of these batteries is relatively small and is therefore only sufficient for short autonomous phases. A standardized 13-pole plug exists as an interface between trailer 5 and towing vehicle 3. The battery is also recharged via this plug. This approach is designed for 12 V and does not permit power transmission at a higher voltage level of, for example, 48 V. In addition, the charging current for the 12 V battery in the trailer is strictly limited by the relatively small cable cross sections.

[0036] There are considerations of increasing the voltage level of the batteries in the trailer, for example, to 48 V, with the goal of achieving a higher capacity and performance and/or at low weight. Solar cells and wheel-driven electric machines are discussed as energy sources, which operate as generators during braking and may thus recharge the batteries.

[0037] The power control device provided here is to enable efficient control or regulation of the generator or motor power on wheel-driven generators.

[0038] Initially, a first implementation will be explained:

[0039] Braked trailers 5 have a pull rod at a drawbar 7, which actuates a deflection lever 15 during braking, whereby a so-called application force results on brake cable 27 and decelerates trailer 5 via wheel brake 25.

[0040] By attaching a sensor system 19 including an angle sensor in the deflection point, i.e., for example, at an axis of deflection lever 15, an electrical sensor signal may be generated which is a function, i.e., for example, proportional, to a drawbar force.

[0041] The electrical sensor signal generated by the angle sensor is relayed to a power control device 13, for example, in the form of a control device, preferably in trailer 5, and processed further there. Power control device 13 computes a setpoint torque or a setpoint power therefrom and activates electric machine 9 acting as a generator accordingly.

[0042] By decoupling the application force from the deflection (pre-tensioning of the drag rope) in a certain small angle range below a minimum orientation angle, a certain idle travel may be generated. This idle travel is characterized in that at low deflection angles of deflection lever 15, wheel brake 25 is not directly actuated. Ideally, this idle angle is used to utilize the power of electric machine 9 preferably extensively and to convert the excess kinetic energy during braking into electric energy. Mechanical brake 25 is to remain preferably inactive and is only to be used with full trailer battery 10 or high decelerations or upon failure of electric machine 9. This method enables efficient use of the excess kinetic energy, because it is not mechanically dissipated as usual in friction brake 25, but rather electrically recuperated.

[0043] An additional mechanical decoupling of the application force from deflection lever 15 in the desired angle range may also be implemented by an installation of a damper 29, for example, a gas pressure damper or an oil pressure damper and/or a spring element. The provided installation position is shown in FIG. 3. The advantage of this approach is that the mechanical connection is maintained and mechanical brake 25 is available as a fallback level in the event of failure of the electrical system.

[0044] The provided example may also be used for a motor assistance. The approach here is to assist or relieve towing vehicle 3 via electric machine 9 installed in trailer 5 in case of sufficiently high electric power. The power of electric machine 9 may be regulated, for example, with the aid of the angle sensor in sensor system 19 in such a way that a positive force in the direction of the towing vehicle does not result via drawbar 7, but rather the pull rod always remains loaded with tension and trailer 5 thus only becomes more or less lighter. This is enabled in that in the case of driving via trailer 5, the angle sensor would supply a positive value, which is not desired in motor operation. As a result, the motor power would be reduced again. This principle has the advantage that towing vehicle 3 may not be pushed by trailer 5, which may be critical for the stability of vehicle combination 1.

[0045] A second implementation is explained hereinafter:

[0046] In the above embodiment, it was described how the activity of mechanical brake 25 on trailer 5 may be avoided and excess kinetic energy may be electrically recuperated. A second step in the direction of increasing efficiency may be to reduce the activity of the mechanical brake on towing vehicle 3 or to avoid it entirely in certain driving situations.

[0047] One possible approach is to incorporate further pieces of information from towing vehicle 3, for example, the braking signal, into the system of power control device 13. This may be carried out, for example, via a wireless OBD dongle, which is connected to an OBD socket of towing vehicle 3 and sends the required signals to power control device 13. This would have the advantage that the driver could trigger the recuperation in trailer 5 via a light actuation of the brake pedal in towing vehicle 3, without mechanical brake 25 already closing. Another example is the use of a gas pedal signal to avoid recuperation from being possible during acceleration, but rather towing vehicle 3 receiving motor assistance, for example, with the aid of electric machine 9 in trailer 5.

[0048] Intelligent energy management for trailer 5 or also for entire vehicle combination 1 may be implemented by a use of GPS data and navigation data (for example, destination).

[0049] Vehicle-combination-spanning energy management may be implemented in that, for example, with sufficiently full trailer battery 10, the vehicle electrical system of towing vehicle 3 may be supplied via a DC-DC converter and the 13-pole plug and the vehicle generator of towing vehicle 3 may thus be switched off.

[0050] Many customer requirements are implementable hereby via various strategies such as arrive preferably efficiently or arrive with preferably lots of electric energy.

[0051] As a supplemental embodiment, it is provided that a wireless control unit or operating unit is used within reach of the driver, i.e., for example, at the steering wheel. This control unit is preferably to communicate via wireless signal transmission (for example, Bluetooth, WLAN, etc.) with a second unit attached to trailer 5, for example, to drawbar 7, which is in turn electrically connected as interface 21 to power control device 13 for electric machine 9. The functionality is to be similar to a retarder in a truck. That means, in the event of an upcoming braking maneuver, for example, in the event of a longer downgrade, the driver may manually set/preselect the recuperation power of trailer 5 in multiple stages. This has the advantage that not only the kinetic energy of trailer 5, but rather also that of towing vehicle 3 is available for the recuperation, mechanical brake 25 is conserved, and vehicle combination 1 is stabilized by the stretching action. A further advantage of the operating unit is that by integrating a visual display, the driver may be informed about a present recuperation condition, a charge level of the battery, etc.

[0052] In summary, specific embodiments of the present invention may enable effective recuperation of the excess kinetic energy in electric energy, since friction losses of mechanical brake 25 are minimized. In principle, a fallback level may be implemented upon failure of the generator power, since the mechanical approach still functions. Specific embodiments may be implemented with minor and cost-effective integration expenditure, since, for example, a drawbar mechanism does not have to be changed or only has to be changed slightly. The principle provided herein may also be used for assisting or relieving towing vehicle 3. Overall, intelligent energy management is possible in vehicle combination 1. This enables a CO.sub.2 savings by supporting the vehicle electrical system and self-powering of the camper.

[0053] Finally, it is to be noted that terms such as having, including, etc. do not exclude other elements or steps and terms such as a or one do not exclude a plurality.