Parking Lock Release Control Using Drivetrain Twist Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for operating motor vehicle powertrain devices fail to accurately determine compensating torque to avoid jerky relaxation of the torque transmission arrangement when releasing the parking lock, leading to unwanted noise and jolts.
Innovation Solution
Determine compensating torque based on the rotation angle and torsional stiffness of the torque transmission arrangement, independent of the vehicle's tilt angle, using a rotary encoder and acceleration sensor to ensure precise calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If compensating torque is determined based on vehicle tilt angle, then the parking lock can be released, but jerky relaxation and unwanted noise occur due to inaccurate torque determination
Solution Approach 1:
The patent replaces the mechanical estimation method (based on tilt angle sensors) with an electronic calculation method using a control unit. The control unit calculates the compensating torque electronically using the formula: compensating torque = torsional stiffness × rotation angle. This substitution enables precise torque determination that prevents jerky relaxation and noise during parking lock release.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors the rotation angle of the torque transmission arrangement and uses this information to calculate and adjust the compensating torque in real-time. The rotary encoder provides feedback on the actual rotation angle, allowing the control unit to precisely determine when the parking lock has been fully released and to adjust the motor torque accordingly, preventing overshoot and jerky motion.
2Productivity
If the parking lock device is released without accurate compensating torque, then the locking element can be freed, but the torque transmission arrangement relaxes jerkily causing discomfort
Solution Approach 1:
The patent applies preliminary action by calculating and applying the compensating torque before the parking lock release is completed. The control unit determines the required compensating torque in advance based on the torsional stiffness and measured rotation angle, then applies this torque through the motor during the release process. This preliminary calculation and application of compensating torque ensures smooth relaxation of the torque transmission arrangement without jolts or disruption.
3Ease of operation
If a motor is used to generate compensating torque, then the parking lock can be released smoothly, but the system complexity increases
Solution Approach 1:
The patent applies universality by making the motor serve multiple functions: it acts as the drive unit for the parking lock mechanism, generates the compensating torque during release, and can also function as a generator during vehicle operation. The control unit that calculates compensating torque also manages other aspects of the parking lock operation and motor control. This multi-functionality reduces the need for separate dedicated components and justifies the added complexity through versatile utility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables smooth and comfortable release of the parking lock by accurately compensating for clamping torque, minimizing disruptive side effects.
Implementation Method 1
a rotary encoder and acceleration sensor to ensure precise calculation
Implementation Method 2
a rotary encoder and acceleration sensor to ensure precise calculation
Implementation Method 3
a motor connected at least temporarily to at least one wheel of the motor vehicle via a torque transmission arrangement
Implementation Method 4
the parking lock device positively engages a locking element
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method for operating a motor vehicle drive train unit for a motor vehicle (1), having a motor that is drivingly connected at least periodically to at least one wheel (9) of the motor vehicle (1) via a torque-transmission assembly and having a parking brake device, wherein the parking brake device interlockingly secures a blocking element that is coupled to the torque-transmission assembly in a rotationally fixed manner in a first setting and releases same in a second setting, and when shifting the parking brake device from the first setting into the second setting, by means of the motor, a compensation torque is generated on the blocking element which counteracts a tensioning torque brought about by a tensioning of the torque-transmission assembly when the blocking element is secured. According to the invention, the compensation torque is determined from a twisting angle of the torque-transmission assembly determined after the securing of the blocking element and from a torsional stiffness of the torque-transmission assembly. The invention also relates to a motor vehicle drive train unit for a motor vehicle (1).