Hybrid Vehicle Controller Occupancy-Based Powertrain Scheduling
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Solution Overview
Problem
Hybrid-electric vehicle powertrains face challenges in balancing fuel efficiency with noise, vibration, and harshness (NVH) considerations, particularly when frequent engine starts/stops, gear shifting, and regenerative braking ratios affect occupant comfort and efficiency.
Innovation Solution
A controller system that detects occupancy status and adjusts the powertrain's operating parameters, such as engine schedules, regenerative braking ratios, and transmission schedules, to optimize efficiency while minimizing NVH impacts based on whether the vehicle is occupied or in autonomous mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the internal-combustion engine is started and stopped more frequently to increase efficiency, then fuel economy is improved, but noise, vibration, and harshness (NVH) increase making occupants uncomfortable
Solution Approach 1:
The patent applies dynamics by making the transmission schedule adjustable based on occupancy status. The control system dynamically switches between different transmission schedules (first schedule for occupied vehicles, second schedule for unoccupied vehicles) to optimize the balance between fuel efficiency and NVH characteristics. This allows the system to adapt its behavior rather than using a fixed schedule, resolving the contradiction between efficiency improvements and comfort maintenance.
2Use of energy by moving object
If hysteresis between upshifting and downshifting is reduced to increase transmission efficiency, then fuel economy is improved, but more frequent gear shifting annoys or distracts occupants
Solution Approach 1:
The patent implements dynamics by providing different transmission schedules for different occupancy conditions. The first transmission schedule (for occupied vehicles) is designed with larger hysteresis bands to reduce frequent shifting, while the second transmission schedule (for unoccupied vehicles) can use smaller hysteresis bands to maximize efficiency. This dynamic adjustment resolves the contradiction between transmission efficiency and occupant comfort.
3Loss of energy
If the ratio of regenerative to friction braking is increased by ramping more quickly to increase energy recoup, then energy efficiency is improved, but an uneven braking feel is produced for occupants
Solution Approach 1:
The patent applies dynamics by adjusting the regenerative braking strategy based on occupancy status. When the vehicle is unoccupied, the system can aggressively ramp up regenerative braking to maximize energy recoup. When occupied, the system uses a more gradual approach to maintain smooth braking feel. This dynamic adjustment resolves the contradiction between energy efficiency and braking comfort.
4Use of energy by moving object
If shifting gears based on battery state of charge is implemented to increase transmission efficiency, then fuel economy is improved, but more frequent shifting occurs which annoys occupants
Solution Approach 1:
The patent implements dynamics by making the transmission control strategy adaptive to occupancy conditions. The first transmission schedule (for occupied vehicles) prioritizes smooth operation and reduces frequency of shifts even if it means slightly less optimal battery charge management. The second transmission schedule (for unoccupied vehicles) can aggressively manage battery charge through frequent shifts. This resolves the contradiction between fuel economy through battery-aware shifting and occupant comfort.
Data Source
AI summary
A hybrid-electric vehicle includes a power system, a controller, a driver seat, a passenger seat, a back seat, and sensors. The controller is in communication with the sensors and the power system. The seats are coupled, directly or indirectly, to the power system. The sensors are configured to detect occupancy of the driver, passenger, and back seats. The controller is programmed to receive occupancy data from the sensors, determine an occupancy status based on the occupancy data, set an operating parameter for the power system based on the occupancy status, and control the power system in accordance with the parameter.