Start-Stop Controller Preventing Roll-Back on Grades
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Solution Overview
Problem
In vehicles equipped with start-stop controls, engine restarts on grades are challenging due to potential vehicle roll-back, necessitating either costly hill-hold devices or reduced fuel economy by avoiding engine stops on grades, as existing systems fail to reliably prevent roll-back without additional hardware or compromising fuel efficiency.
Innovation Solution
A controller system that determines vehicle mass and grade to conditionally prevent engine stops on inclines, using estimates from torque output, telematics, or external sources, allowing engine restarts only when roll-back conditions are met, thus enabling safe launch without additional hardware and maintaining fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hill-hold devices are added to prevent roll-back, then vehicle stability on grades is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical hill-hold devices with a control system that uses engine torque management to prevent roll-back. The controller monitors vehicle conditions and modulates engine torque output to maintain vehicle stability during restart on grades, eliminating the need for additional mechanical hill-hold hardware.
Solution Approach 2:
The engine control system uses the engine's own torque output to prevent roll-back during restart on grades. By controlling the engine restart timing and torque delivery, the system makes the engine self-regulating for stability without requiring external hill-hold devices.
2Reliability
If engine stops are prevented on grades, then vehicle stability is improved, but fuel economy deteriorates
Solution Approach 1:
The patent changes the parameter of engine operation mode based on vehicle conditions. The controller determines whether to allow engine stop or restart based on grade severity and vehicle mass, dynamically adjusting the engine stop condition parameters to balance fuel economy and stability requirements.
Solution Approach 2:
The system dynamically adjusts engine restart behavior based on real-time vehicle conditions including grade and mass. The controller evaluates whether the vehicle is on a grade and adjusts the engine stop logic accordingly, allowing stops on flat terrain for fuel economy while preventing stops on grades where restart control can maintain stability.
3Use of energy by moving object
If engine restart is allowed on grades, then fuel economy is improved, but vehicle stability deteriorates due to roll-back
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors vehicle conditions including grade, mass, and brake status. Based on this feedback, the controller determines whether to allow engine restart and modulates torque delivery to prevent roll-back, enabling fuel economy benefits while maintaining stability through active control.
4Use of energy by moving object
If start-stop control is implemented, then fuel economy is improved, but ease of operation deteriorates due to complex pedal actions required
Solution Approach 1:
The system makes the engine control self-regulating by automatically determining restart conditions based on vehicle state. The controller monitors brake pedal status, vehicle grade, and mass to automatically decide when restart is safe, eliminating the need for drivers to learn complex pedal coordination techniques.
Data Source
AI summary
Controls for improved drivability of a vehicle equipped with start/stop logic are disclosed. A nominal control stop for the internal combustion engine of the vehicle is disabled or prevented from occurring in response to a vehicle mass and route grade indicating a roll back condition for the vehicle exists if the nominal control stop for the engine were to take place.