Parking Lock Engagement Control Using Gradient-Aware Braking
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Solution Overview
Problem
Existing methods for controlling the engagement and disengagement of a vehicle's parking lock can lead to damage and discomfort due to the vehicle rolling into the locking mechanism on inclined roadways, and the prior art is not optimized for securing the vehicle against unintentional movement.
Innovation Solution
The method involves determining the road gradient and longitudinal inclination of the vehicle as a second driving parameter, activating the hydraulic brake system before engaging the parking lock on inclines, and controlling the engagement and disengagement of the parking brake based on threshold values to prevent rolling and interlocking issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the parking lock is actively engaged while the vehicle is still moving or on an incline, then the vehicle can be secured against rolling away, but the vehicle may roll into the locking mechanism causing damage and discomfort
Solution Approach 1:
The hydraulic brake system is activated before the parking lock is engaged to bring the vehicle to a complete standstill and secure it against rolling. This preliminary braking action ensures the vehicle is stationary before the parking lock engages, preventing the vehicle from rolling into the locking mechanism.
Solution Approach 2:
The hydraulic brake system provides a counteracting force against gravity and rolling tendencies before the parking lock engages. By activating the brake system in advance, the invention creates an opposing force that prevents the harmful rolling motion that would otherwise damage the parking lock mechanism.
2Speed
If the parking brake is activated before the parking lock engagement, then the vehicle can be braked to a standstill, but the brake system may cause discomfort or damage if not properly coordinated
Solution Approach 1:
The control unit continuously monitors vehicle speed and the state of the parking lock actuator, and uses this feedback to control the hydraulic brake system. The brake system is activated only when the vehicle speed is above a threshold and deactivated when the vehicle is at a standstill, ensuring smooth and coordinated operation that maintains driving comfort.
Solution Approach 2:
The invention dynamically controls the hydraulic brake system based on real-time vehicle conditions. The brake system is activated and deactivated at appropriate moments during the parking lock engagement process, creating a dynamic coordination between braking and locking actions that ensures smooth operation and driver comfort.
3Loss of time
If the parking lock is engaged without ensuring the vehicle is at a standstill, then the engagement process can be faster, but the locking element may interlock requiring higher force and causing uncomfortable jolts
Solution Approach 1:
The hydraulic brake system is activated in advance to ensure the vehicle reaches a complete standstill before the parking lock engages. This preliminary braking action prevents the locking element from interlocking with moving components, which would otherwise require excessive force to disengage and cause uncomfortable jolts.
Solution Approach 2:
The brake system provides a cushioning effect by gradually bringing the vehicle to a stop before the parking lock engages. This beforehand cushioning prevents sudden impacts and interlocking of the locking element, ensuring smooth engagement without excessive forces or uncomfortable jolts.
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
This approach enhances driving comfort and reduces wear on the parking lock mechanism by ensuring the vehicle is securely braked and locked without rolling into the parking lock, even on steep inclines, thereby preventing damage and discomfort during engagement and disengagement.
Implementation Method 1
the vehicle continues to be braked by means of the parking brake before the parking lock is actively engaged
Data Source
AI summary
A method for controlling an engagement and disengagement of a vehicle transmission parking lock. A vehicle present speed is ascertained when a device for activating the parking lock is actuated. When the vehicle has not yet reached a standstill and the present speed exceeds a threshold value, engagement of the parking lock is prevented. When the vehicle has not yet reached a standstill and the present speed falls below the threshold value, the vehicle activates the parking brake and is braked until the standstill is reached or until the present speed has reached substantially zero. A present gradient value of the roadway and/or a vehicle longitudinal inclination value is also ascertained. Based on these values, it is checked whether a hydraulic brake system of the vehicle is activated or whether the already activated parking brake should be deactivated.