Vehicle Start Torque Control on Low-Adhesion Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing traction control systems fail to ensure a safe starting process on low-friction surfaces like ice or snow, as they often lead to instabilities and excessive slip, and do not effectively manage drive torque distribution to prevent slip.
Innovation Solution
A method and system that determines and limits engine torque based on vehicle mass, road inclination, and friction conditions, incorporating clutch control and regulated brake pressure to maintain optimal adhesion and reduce slip, allowing for a controlled starting process without excessive wheel spin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known traction control systems brake wheels or reduce engine power when slip is detected, then wheel slip is limited, but instabilities or reduced traction can still occur on low adhesion surfaces
Solution Approach 1:
The system determines and limits the maximum engine torque before the starting process begins, based on predicted road adhesion conditions. This preliminary torque limitation prevents excessive wheel slip from occurring in the first place, rather than reacting after slip is detected. The control sequence is activated automatically when low adhesion conditions are predicted, ensuring stable traction from the moment of engine start-up.
2Reliability
If a control action is taken when a wheel speed is reached that causes snow or ice to melt, then wheel slip is reduced, but the adhesion values are further reduced due to the resulting water film
Solution Approach 1:
The system applies preliminary anti-action by limiting engine torque before wheel slip can generate enough heat to melt snow or ice. By determining maximum engine torque based on predicted adhesion conditions and limiting torque output in advance, the system prevents the harmful thermal effect that would create water films and further reduce adhesion.
3Reliability
If known systems reduce drive torque to avoid excessive slip, then wheel spin is limited, but the driver's wishes are not respected and vehicle performance is reduced
Solution Approach 1:
The system dynamically adapts torque limitation based on actual driving conditions and driver input. The maximum engine torque is determined considering the accelerator pedal position, allowing the system to provide full performance when high acceleration is requested while still preventing excessive slip. The control sequence can be deactivated by the driver, and torque limitations are adjusted based on actual wheel slip occurrence, ensuring optimal balance between slip prevention and performance.
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 enables a safer and more stable starting process by limiting engine torque and using clutch and brake control to maintain optimal adhesion, reducing slip and preventing wheel spin on low-friction surfaces, thus improving traction and control.
Implementation Method 1
the wheels are braked depending on this slip
Implementation Method 2
the engine power is reduced in order to limit the slip
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method for controlling a starting process of a vehicle, said method comprising at least the following steps: a) activating a control sequence (R) and setting a control sequence signal (RS), b) defining a maximum motor drive torque (M4_max), c) in the event that a drive request for a starting process is identified - c1) activating a clutch-transmission unit with a clutch engagement process duration greater than a standard clutch engagement process duration provided in the event of a deactivated control sequence, - c2) with control of wheel slip of the driven wheels by determination of wheel speeds of the driven wheels and at least adjustment of a drive torque at the output shaft, - c3) redefining the maximum motor drive torque (M4_max) depending on the wheel slip and a driving speed (v), and d) deactivating the control sequence (R) and resetting the control sequence signal (RS) if limit values (µ_tres, v_tres) are reached.