ESTIMATING LOADS ACTING ON A REAR AXLE OF A MOTOR VEHICLE

Abstract

The disclosure relates to a method to estimate dynamic loads acting vertically on a rear axle of a motor vehicle during a forward driving operation. To enable an estimation of the dynamic loads acting vertically on the rear axle during the forward driving operation of the motor vehicle cost-effectively, the dynamic loads are estimated in consideration of dynamic mechanical forces engaging vertically at a front axle of the motor vehicle during the forward driving operation. In addition, dynamic acceleration forces engaging at a spring mass of the motor vehicle during the forward driving operation are also considered when estimating the dynamic loads during the forward driving operation.

Claims

1. A method to dampen a vehicle suspension comprising: using dynamic mechanical forces that engage vertically at a front axle and dynamic acceleration forces that engage at a spring mass during a forward driving operation of a vehicle to estimate dynamic loads acting vertically on a rear axle; and dampening, via a continuously controlled and adjusted damping system, the rear axle.

2. The method as claimed in claim 1 further comprising detecting spring deflections and spring velocities at each of wheel suspensions of the front axle to ascertain the dynamic mechanical forces.

3. The method as claimed in claim 1 further comprising detecting, sensorially, vertical movements of the spring mass, roll movements of the spring mass about a vehicle longitudinal axis, and pitch movements of the spring mass about a vehicle transverse axis to ascertain the dynamic acceleration forces.

4. The method as claimed in claim 1 further comprising estimating the dynamic mechanical forces that engage at the front axle from the dynamic loads via the dynamic mechanical forces and the dynamic acceleration forces.

5. The method as claimed in claim 4 further comprising dampening, via the continuously controlled and adjusted damping system, the dynamic mechanical forces.

6. A vehicle damping system comprising: an electronic system configured to, during a forward driving operation of a vehicle, dampen a rear axle based on an estimation of dynamic loads from dynamic mechanical forces engaging vertically at a front axle of the vehicle and dynamic acceleration forces engaging at a spring mass of the vehicle.

7. The vehicle damping system as claimed in claim 6 further comprising sensors associated with various wheel suspensions of the front axle that detect spring deflections and spring velocities of each individual wheel suspension, wherein the electronic system is configured to ascertain the dynamic mechanical forces based on detected spring deflections and spring velocities.

8. The vehicle damping system as claimed in claim 6 further comprising a sensor system that detects vertical movements of the spring mass, roll movements of the spring mass about a vehicle longitudinal axis, and pitch movements of the spring mass about a vehicle transverse axis, wherein the electronic system is configured to ascertain the dynamic acceleration forces from detected vertical movements of the spring mass, roll movements of the spring mass about a vehicle longitudinal axis, and pitch movements of the spring mass about a vehicle transverse axis.

9. The vehicle damping system as claimed in claim 6, wherein the electronic system is configured to estimate dynamic mechanical forces engaging at the rear axle based on the dynamic mechanical forces and the dynamic acceleration forces, and calculate the dynamic loads therefrom.

10. The vehicle damping system as claimed in claim 9, wherein the electronic system is configured to dampen the dynamic mechanical forces.

11. A vehicle comprising: a damping system configured to, during a forward driving operation of the motor vehicle, dampen a rear axle based on an estimation of dynamic loads from dynamic mechanical forces engaging vertically at a front axle of the motor vehicle and dynamic acceleration forces engaging at a spring mass of the motor vehicle.

12. The vehicle as claimed in claim 11 further comprising sensors associated with various wheel suspensions of the front axle that detect spring deflections and spring velocities of each individual wheel suspension, wherein the damping system is configured to ascertain the dynamic mechanical forces based on detected spring deflections and spring velocities.

13. The vehicle as claimed in claim 11 further comprising a sensor system that detects vertical movements of the spring mass, roll movements of the spring mass about a vehicle longitudinal axis, and pitch movements of the spring mass about a vehicle transverse axis, wherein the electronic system is configured to ascertain the dynamic acceleration forces from detected vertical movements of the spring mass, roll movements of the spring mass about a vehicle longitudinal axis, and pitch movements of the spring mass about a vehicle transverse axis.

14. The vehicle as claimed in claim 11, wherein the damping system is configured to estimate dynamic mechanical forces engaging at the rear axle based on the dynamic mechanical forces and the dynamic acceleration forces, and calculate the dynamic loads therefrom.

15. The vehicle as claimed in claim 14, wherein the damping system is configured to dampen the dynamic mechanical forces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a flow chart of an exemplary embodiment of a method according to the disclosure; and

[0029] FIG. 2 shows a schematic illustration of an exemplary embodiment of a motor vehicle according to the disclosure.

DETAILED DESCRIPTION

[0030] As required, detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

[0031] FIG. 1 shows a flow chart of an exemplary embodiment of a method according to the disclosure that estimates dynamic loads acting vertically on a rear axle of a motor vehicle during a forward driving operation of the motor vehicle.

[0032] In method step 110, dynamic mechanical forces engaging at a front axle of the motor vehicle during the forward driving operation of the motor vehicle are ascertained in consideration of respective spring deflections and/or spring velocities detected at wheel suspensions of the front axle. At the same time, dynamic acceleration forces engaging at a spring mass of the motor vehicle during the forward driving operation of the motor vehicle are ascertained from sensorially detected vertical movements of the spring mass, roll movements of the spring mass about a vehicle longitudinal axis, and/or pitch movements of the spring mass about a vehicle transverse axis.

[0033] In method step 120, the dynamic loads acting vertically on the rear axle of the motor vehicle are estimated in consideration of the dynamic mechanical forces ascertained in method step 110 and the dynamic acceleration forces ascertained in method step 110. It can be provided in this case that, firstly, dynamic mechanical forces engaging at the rear axle are estimated in consideration of the dynamic mechanical forces ascertained in method step 110 and the dynamic acceleration forces ascertained in method step 110, from which subsequently the dynamic loads are ascertained. Alternatively, the dynamic loads can be estimated directly from the dynamic mechanical forces ascertained in method step 110 and the dynamic acceleration forces ascertained in method step 110. Method step 120 is carried out via an algorithm executed by an analysis electronics system of the motor vehicle.

[0034] FIG. 2 shows a schematic illustration of an exemplary embodiment of a motor vehicle 1 according to the disclosure.

[0035] The motor vehicle 1 comprises a continuously controlled and/or adjusted damping system 2, which can be constructed conventionally, because of which a more precise description of the damping system 2 will be omitted. Using the damping system 2, a respective damping force generated by damping units 3 of the damping system 2 can be adapted individually to a respective driving situation, wherein the damping units 3 are associated with individual wheel suspensions 4 of the motor vehicle 1. The damping units 3 are activated via an activation unit 5 of the damping system 2. The activation unit 5 may be a microprocessor, or controller, as is known in the art.

[0036] The motor vehicle 1 moreover comprises a system 6 that estimates dynamic loads acting vertically on a rear axle 7 of the motor vehicle 1 during a forward driving operation of the motor vehicle 1.

[0037] The system 6 comprises sensors 9 associated with various individual wheel suspensions 4 of a front axle 8, using which spring deflections and/or spring velocities of the single, individual wheel suspensions 4 are detectable. Furthermore, the system 6 comprises a sensor system 10 in the form of an inertial measuring unit that detects vertical movements of a spring mass of the motor vehicle 1, roll movements of the spring mass about a vehicle longitudinal axis, and/or pitch movements of the spring mass about a vehicle transverse axis.

[0038] The system 6 furthermore comprises an analysis electronics system 11, which is connected to the damping system 2, the sensors 9, and the sensor system 10, and can moreover receive and process CAN bus signals of the motor vehicle 1.

[0039] The analysis electronics system 11 is configured to ascertain dynamic mechanical forces engaging vertically at the front axle 8 of the motor vehicle 1 during the forward driving operation in consideration of respective spring deflections and/or spring velocities detected at individual wheel suspensions 4 of the front axle 8 using the sensors 9. Furthermore, the analysis electronics system 11 is configured to ascertain dynamic acceleration forces engaging at the spring mass of the motor vehicle 1 during the forward driving operation from vertical movements of the spring mass, roll movements of the spring mass about a vehicle longitudinal axis, and/or pitch movements of the spring mass about a vehicle transverse axis detected via the sensor system 10. For this purpose, the analysis electronics system 11 can be configured to ascertain both an acceleration state at a center of gravity of the spring mass of the motor vehicle 1 and also at four corners of the motor vehicle 1.

[0040] The analysis electronics system 11 is configured to estimate the dynamic loads acting vertically on the rear axle 7 of the motor vehicle 1 in consideration of the dynamic mechanical forces engaging vertically at the front axle 8 of the motor vehicle 1 during the forward driving operation, which have been ascertained by the analysis electronics system 11, and the dynamic acceleration forces engaging at the spring mass of the motor vehicle 1 during the forward driving operation, which have been ascertained by the analysis electronics system 11. For this purpose, the analysis electronics system 11 can be configured to estimate dynamic mechanical forces engaging at the front axle 8 in consideration of the dynamic mechanical forces and the dynamic acceleration forces, and subsequently ascertain the dynamic loads therefrom.

[0041] The damping system 2 is configured to consider the dynamic loads estimated using the system 6 in the ascertainment of damping forces to dampen the rear axle 7.

[0042] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosure. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the disclosure.