Cam Phaser Torque Array Selection for Hybrid Powertrain
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Solution Overview
Problem
In hybrid vehicles, the uncertainty in engine torque due to the rapid switching of camshaft phasers leads to suboptimal transmission gear selection and delayed powertrain torque development, as the distributed controller system faces challenges in accurately communicating torque availability between control modules.
Innovation Solution
A method is implemented to determine the state of the cam phaser system, selecting appropriate engine torque arrays based on its activity, monitoring engine operating parameters, and updating these arrays to accurately calculate and regulate engine torque, considering factors like ambient temperature and pressure, to ensure precise torque management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the cam phaser system switches rapidly between enabled and disabled states, then the engine can quickly adapt torque output, but the control system experiences uncertainty in available engine torque
Solution Approach 1:
The system pre-calculates and stores multiple engine torque arrays corresponding to different cam phaser states (enabled/disabled) and various operating conditions. When the cam phaser state changes, the controller immediately selects the appropriate pre-computed torque array without waiting for actual torque measurement, eliminating the uncertainty period and enabling instant accurate torque management.
2Measurement precision
If the optimizer control module waits for communicated torque data from other controllers, then torque calculations can be accurate, but transmission gear selection and powertrain torque development are delayed
Solution Approach 1:
The system pre-computes engine torque values for various operating conditions and cam phaser states and stores them in torque arrays. The optimizer control module immediately selects from these pre-calculated values based on current sensor inputs, eliminating communication delays while maintaining accurate torque management.
Solution Approach 2:
The patent introduces an intermediary torque estimation mechanism that uses sensor data (camshaft position, crankshaft speed, throttle position) to directly determine available torque from pre-stored arrays, bypassing the need to wait for torque data communication from other control modules.
3Adaptability or versatility
If the system uses a distributed controller architecture with multiple control modules, then system functionality is enhanced, but communication time delays occur between modules
Solution Approach 1:
The patent extracts the torque calculation function from the distributed control modules and implements it locally within the optimizer control module using pre-computed torque arrays. This eliminates the need for time-consuming inter-module communication while preserving the benefits of distributed architecture for other vehicle functions.
Data Source
AI summary
A method of regulating a torque output of an internal combustion engine in a hybrid electric vehicle includes determining whether a cam phaser system of the engine is in one of an inactive state and an active state and monitoring at least one engine operating parameter. An engine torque array is selected from a plurality of engine torque arrays based on the one of the inactive state and the active state. An available engine torque is determined based on the engine torque array and the at least one engine operating parameter and the engine is regulated based on the available engine torque.