Dynamic Torque Control for Powertrain Oscillation Reduction
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Solution Overview
Problem
Current torque control systems in vehicles, which use static torque ramps, fail to optimize engine torque requests across various driving modes, leading to reduced vehicle performance and discomfort due to powertrain oscillations.
Innovation Solution
A dynamic torque control system that adjusts torque demand based on current torque values, moment of inertia, desired torque derivatives, rotational speed differences, and calibration parameters to minimize rotational speed differences and provide a smooth, oscillation-free torque profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If static torque ramps are used to limit engine torque requests, then powertrain oscillations are reduced, but vehicle performance is unnecessarily reduced in driving modes where oscillations would not occur
Solution Approach 1:
The patent transitions from static torque ramps to dynamic torque control. The torque request is continuously adjusted based on real-time measurements of rotational speed difference between engine and wheels, allowing the system to adapt torque limiting to actual driving conditions. This enables high performance when no oscillation risk exists while providing targeted torque limitation only when oscillations are detected.
Solution Approach 2:
The system implements feedback control by continuously measuring the rotational speed difference between engine and wheels, and using this information to dynamically adjust the torque request. The control unit monitors the actual state and modifies torque ramps in real-time, creating a closed-loop system that responds to actual oscillation conditions rather than applying fixed limitations.
2Object-affected harmful factors
If static torque ramps are used to prevent powertrain oscillations, then vehicle comfort is improved, but the torque request is not sufficiently limited in certain driving modes, allowing oscillations to occur
Solution Approach 1:
The system uses dynamic torque control that continuously adapts to changing driving conditions. By measuring the rotational speed difference in real-time, the system can dynamically adjust torque ramps to provide sufficient limitation in oscillation-prone driving modes while maintaining comfort. The torque control is no longer fixed but responds to actual system state.
Solution Approach 2:
The feedback mechanism continuously monitors rotational speed difference and adjusts torque requests accordingly. This ensures that torque limitation is applied with appropriate intensity for each specific driving condition, reliably preventing oscillations when needed while avoiding unnecessary limitations that would reduce comfort.
3Device complexity
If torque ramps are used to control engine torque requests, then the complexity of the control system is reduced, but the control precision is insufficient to optimize torque for all driving modes
Solution Approach 1:
The system implements dynamic torque control that continuously adjusts torque requests based on real-time measurements. The control unit calculates optimal torque ramps dynamically using measured rotational speed differences, providing precise torque optimization for each driving mode without requiring excessively complex hardware or control algorithms.
Solution Approach 2:
The feedback control mechanism uses real-time measurements of rotational speed difference to continuously optimize torque requests. This feedback loop enables precise torque control adaptation to different driving modes while maintaining reasonable system complexity, as the control logic builds on existing torque ramp concepts rather than requiring entirely new complex systems.
Data Source
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AI summary
The present invention relates to a method and a system for the control of a torque Tqdemand requested from the engine, wherein the engine provides a dynamic torque Tqfw in response to a torque Tqdemand requested from the engine. According the present invention, the requested torque Tqdemand is controlled at least based on a current value Tqfw_pres for the dynamic torque, a moment of inertia J for the powertrain, a desired derivative Ṫqfw_req of the dynamic torque related to a spring constant k for the powertrain; T˙qfw_reqk; a current rotational difference Δωpres between a first rotational speed ω1 for a first end of the powertrain and a second rotational speed ω2 for a second end of the powertrain, and a calibration parameter τcal related to a transient for the dynamic torque in the direction of the desired derivative Ṫqfw_req, wherein the current rotational speed difference Δωpres is minimised.