Super-Creep Torque Control for Hybrid Powertrain Failures
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Solution Overview
Problem
Conventional limited operating strategies for hybrid electric vehicle powertrains are inadequate in managing powertrain control failures, leading to restricted mobility and increased risk of wheel spin on low-friction surfaces during 'quit-on-the-road' events, as they rely on fixed throttle angles and lack effective torque control.
Innovation Solution
A 'super-creep' strategy employing closed-loop control with estimated wheel torque and torque feedback to deliver variable powertrain torque, allowing for smoother acceleration and brake override features to manage vehicle speed, reducing the risk of wheel spin and enhancing control over a range of conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed throttle angle is commanded to implement limited operating strategy, then the vehicle can operate in a limited power mode during control failure, but the vehicle cannot navigate grades or provide smooth acceleration
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed throttle angle to a dynamic throttle control system that adjusts the throttle angle in real-time based on feedback from acceleration sensors and torque estimators, enabling smooth acceleration control during limited operating strategy mode
Solution Approach 2:
The patent implements feedback control by using acceleration sensors to monitor actual vehicle acceleration and comparing it with desired acceleration, then adjusting the throttle angle accordingly to achieve the desired acceleration profile during powertrain control failure
2Device complexity
If conventional limited operating strategy is used with fixed throttle angle, then the control system is simple to implement, but the vehicle experiences wheel spin on low-friction surfaces and cannot respond to varying road conditions
Solution Approach 1:
The patent uses feedback from acceleration sensors and torque estimators to continuously monitor vehicle state and adjust throttle angle in real-time, enabling the system to adapt to varying road conditions including low-friction surfaces while preventing wheel spin
Solution Approach 2:
The patent implements self-service by using the vehicle's own acceleration sensors and torque estimators to automatically adjust the throttle control without requiring external intervention, enabling the system to adapt to road conditions autonomously
3Reliability
If fixed limited power is commanded from the engine, then the vehicle can operate safely during control failure, but the vehicle cannot achieve desired acceleration rates or navigate grades
Solution Approach 1:
The patent applies dynamics by making the throttle angle a dynamic variable that changes in real-time based on feedback from acceleration sensors, allowing the vehicle to achieve desired acceleration rates and navigate grades while maintaining safe operation during control failure
Solution Approach 2:
The patent changes the parameter of throttle angle from a fixed value to a dynamically adjusted value based on feedback control, enabling the vehicle to vary power output to achieve desired acceleration rates while maintaining safe operation limits
Data Source
AI summary
A method for controlling torque delivery in a vehicle powertrain using an enhanced limited operating strategy. The strategy is implemented when a powertrain controller fails to respond properly to a driver command for traction wheel torque whereby a modified wheel torque at vehicle traction wheels under driver control is made available.