Hybrid Vehicle Braking Mode Transition Control
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Solution Overview
Problem
Hybrid vehicles face challenges in transitioning between regenerative braking and friction braking modes without disturbing the driver, as limited electrical storage capacity often necessitates a switch from regenerative to friction braking, leading to noticeable changes in vehicle behavior during acceleration or deceleration.
Innovation Solution
The method involves adjusting driveline braking torque and friction braking torque in response to the energy storage device's state of charge, where a reduction in regenerative braking torque is matched by an increase in friction braking torque, allowing for seamless transitions between braking modes without disturbing the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is used to convert kinetic energy to electrical energy, then energy recovery is improved, but the electrical storage capacity becomes limited and requires transition to friction braking
Solution Approach 1:
The patent combines regenerative braking and friction braking systems into a unified braking system that can operate in different modes. The friction braking system is integrated with the regenerative braking system, allowing the vehicle to switch between or combine both braking methods based on energy storage capacity, thereby resolving the limitation of electrical storage capacity while maintaining energy recovery benefits.
Solution Approach 2:
The patent implements dynamic switching between regenerative braking and friction braking modes based on real-time monitoring of energy storage device state of charge. The control system dynamically adjusts the braking mode transition point and torque distribution to optimize energy recovery while preventing overcharging, thus adapting to changing storage capacity conditions.
2Quantity of substance
If transition from regenerative braking to friction braking is implemented, then energy storage limitation is resolved, but driver disturbance occurs due to vehicle acceleration or deceleration changes
Solution Approach 1:
The patent applies preliminary action by anticipating the need for braking mode transition and preparing the friction braking system in advance. The control system monitors energy storage state of charge continuously and initiates friction braking engagement before the transition point is reached, ensuring smooth torque transfer and preventing sudden changes in vehicle deceleration that would disturb the driver.
Solution Approach 2:
The patent utilizes parameter changes by continuously adjusting the state of charge threshold for braking mode transition based on driving conditions, vehicle speed, and brake system temperature. This dynamic parameter adjustment allows smooth transition between braking modes while maintaining driver comfort and optimizing energy recovery opportunities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces braking disturbances and improves vehicle drivability by ensuring a smooth transition between regenerative and friction braking modes, enhancing the overall driving experience.
Implementation Method 1
During regenerative braking, the vehicle's kinetic energy is converted into electrical energy and stored for later use
Implementation Method 2
friction braking converts the vehicle's kinetic energy into heat which is dissipated and lost to the surrounding atmosphere
Data Source
AI summary
Systems and methods for improving operation of a hybrid vehicle are presented. In one example, a method for transitioning between driveline braking and wheel brakes is provided.