Method for operating a motor vehicle in order to detect an overload on a roll stabilizer

Abstract

The invention relates to a method for operating a motor vehicle in order to detect an overload on a roll stabilizer which is supported so that it can rotate on a vehicle body and includes two stabilizer parts that can be rotated relative to each other by a torsional angle () via a rotary drive arranged between these parts. In order to detect an impairment to the driving safety of the vehicle in a timely manner, a ratio of the torsional angle () to a variable which is equivalent to an applied torque (M) of the rotary drive is ascertained, and an overload is determined if the ratio lies outside of a specified tolerance range.

Claims

1. A method for operating a motor vehicle including a roll stabilizer supported for rotation on a vehicle body with two stabilizer parts that are rotatable relative to each other by an angle of torsion via a rotary drive arranged between said two stabilizer parts, the method comprising: collecting data by at least one sensor; receiving, by a control unit, a parameter equivalent to an applied torque (M) of the rotary drive, wherein the parameter equivalent to an applied torque (M) is determined based on the data; determining, by the control unit, a ratio of the angle of torsion () to the parameter equivalent to an applied torque (M) of the rotary drive; comparing, by the control unit, the ratio to a specified tolerance range; and detecting, by the control unit, an overload state if the ratio is outside of the specified tolerance range.

2. The method according to claim 1, wherein the equivalent parameter is determined by a torque sensor detecting the torque of the rotary drive.

3. The method according to claim 1, wherein the equivalent parameter is determined by a pressure sensor detecting a pressure for providing the torque of the rotary drive which is a hydraulic rotary drive.

4. The method according to claim 1, further comprising carrying out the determining of the equivalent parameter by a force sensor arranged on a support of the roll stabilizer on the vehicle body and detecting supporting forces of the roll stabilizer relative to the vehicle body.

5. The method according to claim 4, further comprising with reference to a vehicle model of a motor vehicle formed from operating parameters and sensors, determining the supporting forces of the roll stabilizer relative to the vehicle body and the determined supporting forces form the equivalent parameters.

6. The method according to claim 1, further comprising forming an angle of torsion characteristic curve with a tolerance characteristic curve set apart from the angle of torsion characteristic curve with reduced torques (M) from the torque (M) and the angle of torsion () and determining the overload state if the torque (M) of the tolerance characteristic curve falls below the angles of torsion () allocated to said characteristic curves.

7. The method according to claim 1, wherein the angle of torsion () is determined by an internal angle of torsion (internal) of the rotary drive minus an external angle of torsion (external) determined at ends of the stabilizer parts.

8. The method according to claim 1, wherein the overload state is determined if the angle of torsion () exceeds a maximum specified angle of torsion (max).

9. The method according to claim 1, wherein the overload state is started at angles of torsion () greater than a specified angle of torsion (i) for the torque (M) exceeding a friction-dependent basic moment (Mg).

10. The method of claim 1, wherein the equivalent parameter is determined by an electrical parameter of the rotary drive which is an electromechanical rotary drive.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The present method is explained in more detail with reference to the single FIGURE. This shows the torque to be applied for an angle of torsion set between two stabilizer parts, such as stabilizer arms.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(2) The FIGURE shows the diagram 1 with the torque M to be applied by a rotary drive of a roll stabilizer for setting the angle of torsion of stabilizer parts, such as torsion springs, stabilizer arms, and the like. The angle of torsion characteristic curve 2 shown as a straight line produces the relationship of the roll stabilizer operating without interference between torque M and angle of torsion . With increasing twisting of the stabilizer arms, the torque M to be applied by the rotary drive increases. The angle of torsion is formed as an effective angle of torsion from the difference .sub.internal-.sub.external of the internal angle of torsion .sub.internal and the external angle of torsion .sub.external. Here, the internal angle of torsion .sub.internal indicates the angle of twisting of the parts of the rotary drive and the external angle of torsion .sub.external indicates the twisting angle of the ends of the stabilizer arms. Due to aging, wear, and production variance, in addition to the angle of torsion characteristic curve 2, the torque M reduced for corresponding angles of torsion here parallel tolerance characteristic curve 3 is also produced, which shows the still permissible behavior of the roll stabilizer. If the torque M to be applied by means of the set angle of torsion .sub.i up to the maximum angle of torsion .sub.max is between the regular moment M.sub.n and the tolerance moment M.sub.t, an interference-free operation of the roll stabilizer is detected. Here, due to friction and the like, the basic moment M.sub.g is to be applied by the rotary drive. To prevent incorrect detections of an overload state of the roll stabilizer at small angles of torsion , the method for detecting an overload state is started only at angles of torsion , for example at angles of torsion exceeding the angle of torsion .sub.i, for which torques M to be applied that are significantly over the basic moment M.sub.g are required.

(3) If the torques M to be applied up to the maximum angle of torsion .sub.max are below the tolerance characteristic curve 3 that is provided here as threshold M.sub.s, an overload state of the roll stabilizer, for example, plastic deformation or fracture, is detected and, for example, the motor vehicle is stopped, a maximum vehicle speed is set (limp-home), or another measure is taken to protect the occupants from a dangerous situation by the motor vehicle.

(4) Alternatively or additionally, an overload state can also be detected if an angle of torsion can be set greater than the maximum angle of torsion .sub.max, because such angles of torsion are outside of the roll stabilizer specifications and thus would lead to plastic deformation or a fracture of components of the roll stabilizer.

LIST OF REFERENCE NUMBERS

(5) 1 Diagram 2 Angle of torsion characteristic curve 3 Tolerance characteristic curve M Torque M.sub.g Basic moment M.sub.n Regular moment M.sub.s Threshold M.sub.t Tolerance moment Angle of torsion .sub.external External angle of torsion .sub.internal Internal angle of torsion .sub.max Maximum angle of torsion .sub.i Angle of torsion