Hybrid Powertrain Gear Shifting Control for Fuel Economy
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Solution Overview
Problem
Current gear shifting methods in hybrid powertrains do not effectively minimize fuel consumption while optimizing drivability and performance, as they often rely on maintaining high engine speeds to ensure torque delivery, which increases fuel consumption.
Innovation Solution
A method for gear shifting in hybrid powertrains that determines the energy level in the energy storage unit and acceleration ability to set a target engine speed, allowing for earlier upshifting and more frequent use of the electric machine, thereby reducing fuel consumption and optimizing drivability by controlling the gear shifting based on these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine speed is maintained at a high level to ensure torque delivery after upshifting, then the driveability and torque requirements are met, but the fuel consumption increases
Solution Approach 1:
The patent applies dynamics by making the target engine speed adjustable rather than fixed. The control unit dynamically adapts the target engine speed based on real-time conditions including energy storage level, vehicle speed, and acceleration requests. This allows the system to lower the target engine speed when conditions permit (reducing fuel consumption) while maintaining sufficient torque delivery when needed (preserving reliability).
Solution Approach 2:
The patent changes the parameter of target engine speed from a conventional fixed value to a variable parameter that can be adjusted based on system state. By modifying this key parameter dynamically, the system achieves lower fuel consumption during normal operation while ensuring torque requirements are met during acceleration or when energy is available from storage.
2Use of energy by moving object
If the target engine speed is lowered to reduce fuel consumption, then energy efficiency improves, but the acceleration ability and drivability may be compromised
Solution Approach 1:
The patent implements feedback by continuously monitoring the vehicle's acceleration request, current speed, and energy storage level. The control unit uses this feedback to dynamically adjust the target engine speed. When acceleration is requested or energy is available in storage, the system allows lower target speeds for fuel efficiency; when acceleration capability is needed, the target speed is adjusted to maintain performance.
Solution Approach 2:
The patent makes the gear shifting system multi-functional by enabling it to serve both fuel efficiency and acceleration performance needs. The same control unit and gear shifting mechanism adapt their behavior based on system state, providing fuel-efficient operation during steady-state driving while maintaining acceleration capability when requested, thus serving multiple functions with a single system.
3Loss of energy
If the gear shifting is controlled to maintain optimum engine speed for fuel consumption, then energy efficiency improves, but the adaptability to varying driving conditions decreases
Solution Approach 1:
The patent applies dynamics by transitioning from static, pre-defined shift patterns to dynamic, real-time adaptation. The control unit continuously adjusts the target engine speed based on current driving conditions, energy storage state, and vehicle speed. This dynamic approach maintains fuel efficiency while adapting to varying driving conditions, resolving the contradiction between optimization and adaptability.
Data Source
AI summary
The invention relates to a method, system, vehicle, and computer program product for gear shifting in a hybrid powertrain, that comprises an internal combustion engine; an electric machine; a gearbox; and an energy storage unit connected to the electric machine, and at least one control unit arranged in communication with the internal combustion engine, the electric machine, the gearbox and the energy storage unit. The method comprises the steps of: determining an energy level in the energy storage unit; determining an acceleration ability with a subsequent gear; determining a target engine speed for the internal combustion engine based on the energy level in the energy storage unit and the acceleration ability; and controlling the gear shifting based on the target engine speed.