Torque Coordination for Powertrain Actuator Control
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Solution Overview
Problem
Powertrain systems with multiple torque-generative devices often experience torque lag during transient or directional changes in driver requests, leading to degraded drive quality due to poor coordination of propulsion torque actuators and system constraints, resulting in driveline lash and clunk.
Innovation Solution
A method for controlling powertrain systems that interprets driver requests, determines torque limits, and coordinates propulsion torque actuator commands to improve vehicle drive quality by employing a torque control routine that calculates output torque ranges, applies output torque shaping, and considers driver accelerator pedal busyness and quiescence to manage directional changes effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple torque-generative devices are employed to increase powertrain capability, then system power and versatility are improved, but torque coordination complexity and driveline clunk increase
Solution Approach 1:
The patent introduces an intermediary control system that acts as a mediator between multiple torque-generative devices (ICE and electric machines). This control system coordinates torque distribution by interpreting driver requests, determining torque limits for each actuator, and generating coordinated torque commands. The intermediary controller prevents driveline clunk by ensuring smooth torque transitions and proper coordination among parallel torque sources, thereby managing the complexity of multi-actuator systems.
2Reliability
If torque limits are applied to satisfy system constraints, then system reliability is improved, but torque response speed and drive quality deteriorate
Solution Approach 1:
The patent implements dynamic torque limit coordination that adapts to real-time system conditions and driver requests. Rather than applying static torque limits, the control system dynamically adjusts torque distribution among actuators based on current operating state, driver intent, and system constraints. This dynamic approach allows the system to maintain reliability while improving torque response speed and reducing driveline clunk during transient conditions.
Solution Approach 2:
The control system performs preliminary torque limit determination before actual torque application. By pre-calculating appropriate torque limits based on system constraints and driver requests, the system prepares coordinated torque commands in advance, enabling faster response when driver input changes while still respecting system boundaries and maintaining reliability.
3Ease of operation
If torque coordination control is implemented to reduce driveline clunk, then drive quality is improved, but control system complexity increases
Solution Approach 1:
The patent implements a universal control framework that handles multiple functions within a single coordination system. The control system simultaneously interprets driver requests, determines torque limits for multiple actuators, coordinates torque distribution, and manages system constraints. This multi-functional approach consolidates control complexity into a unified system rather than requiring separate control mechanisms for each function, thereby improving drive quality while managing overall system complexity.
Data Source
AI summary
A powertrain system employing multiple propulsion torque actuators is described. A method for controlling the powertrain system includes interpreting a driver request, including determining a driver torque request and a regenerative braking request based upon driver inputs to an accelerator pedal and a brake pedal. A desired request is determined based upon the driver torque request and the regenerative braking request. Torque limits for the powertrain system are coordinated based upon the desired request, the driver torque request, and a previous driver torque request to determine upper and lower output torque limits, and the upper and lower output torque limits are combined with system constraints to generate a final torque request. The final torque request is employed to determine torque commands for the propulsion torque actuators, and the propulsion torque actuators are controlled based upon the torque commands for the propulsion torque actuators.