Commercial Vehicle Drivetrain Torque Limiting Under Dynamic Load
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Solution Overview
Problem
Existing torque limiting methods in vehicles, particularly commercial vehicles, fail to dynamically adjust torque limits based on current operating conditions, leading to mechanical overloading of the drive train during dynamic situations and unnecessary torque limitations, which can reduce driving performance.
Innovation Solution
A method and device that regularly recalculates the torque limit value using current operating parameters such as driving resistance, energy loss, and energy consumption, allowing the drive motor to output higher torque without mechanically overloading the drive train, thereby preventing overloading and enhancing driving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static torque limit value is stored in the engine control unit, then the drivetrain components are protected from mechanical overloading under normal conditions, but the maximum permissible load torque is exceeded during dynamic operating situations due to powertrain inertia
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static torque limit value stored in memory to a dynamically calculated torque limit value. The calculation device continuously computes the torque limit based on current operating parameters such as vehicle speed, acceleration, and drivetrain component characteristics. This dynamic calculation allows the torque limit to adapt to changing operating conditions, preventing mechanical overloading during transient situations while enabling higher torque output when safe, thus resolving the contradiction between component protection and dynamic operating capability
Solution Approach 2:
The patent implements feedback by using the calculation device to continuously monitor current operating parameters and adjust the torque limit value accordingly. The system feeds back information about actual drivetrain loading conditions from sensors and vehicle operation data, then recalculates the appropriate torque limit in real-time. This closed-loop feedback mechanism ensures the torque limit reflects actual component capacity under current conditions, resolving the contradiction between fixed protection and adaptive performance
2Ease of manufacture
If the drive motor torque is limited to a fixed torque limit value, then manufacturing costs and vehicle weight are reduced through smaller drivetrain components, but the drive motor cannot operate at higher torque in situations where the permissible load limit is not reached
Solution Approach 1:
The patent resolves this contradiction by making the torque limit dynamic rather than fixed. The calculation device computes the maximum permissible torque limit based on real-time operating parameters, allowing the torque limit to increase when drivetrain components can safely handle higher loads and decrease when protection is needed. This enables the use of optimally sized components while extracting maximum performance when conditions permit
Solution Approach 2:
The patent applies parameter changes by varying the torque limit value based on changing operating conditions such as vehicle speed, acceleration rate, gear selection, and drivetrain thermal state. Instead of maintaining a constant conservative torque limit, the system adjusts the torque parameter dynamically to match actual component capacity, thereby enabling higher productivity when safe while maintaining adequate component protection
Data Source
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AI summary
The invention relates to a method for operating a vehicle, in particular a commercial vehicle, wherein the vehicle (1) has a drive train (3) with a drive motor (5), in particular designed as an internal combustion engine, wherein the vehicle (1) has a torque limiting device (33) by means of which the drive torque of the drive motor (5), in particular internal engine torque, is limited to a defined torque limit value, in particular in such a way that the other components of the drive train (3) are not mechanically overloaded.According to the invention, the vehicle has a calculation device (35) by means of which the torque limit value is calculated regularly, in particular at a defined time interval, taking into account at least one determined current operating parameter of the vehicle (1), and the drive torque of the drive motor (5) is limited to the calculated current torque limit value by means of the torque limiting device (33). The calculated torque limit value limits the internal drive torque of the drive motor (5), and the torque limit value is calculated by means of a torque balance at a defined section (19) of the drive train (3). In the torque balance, a flywheel torque value is taken into account as the maximum permissible torque at the flywheel (19).A difference value between the flywheel torque value and a driving resistance torque value formed by the current driving resistance of the vehicle (1) acting on the flywheel is calculated, whereby a dynamic driving resistance torque value is calculated by dividing the calculated difference value by the primary-side total mass moment of inertia of the vehicle (1) and multiplying the calculated difference value by the mass moment of inertia of the drive motor (5), which is taken into account in the torque balance.