Regenerative Braking Controller for Hybrid Vehicle Distance Reduction
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Solution Overview
Problem
Hybrid vehicles face challenges in efficiently reducing distance to a forward detected object while minimizing energy loss and maintaining safety, particularly when regenerative braking power exceeds the maximum recuperation capability.
Innovation Solution
A vehicle system with a controller that decelerates using regenerative braking at a first rate and then transitions to friction brakes at a second rate to achieve a minimum distance and zero speed differential, optimizing energy recovery and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is used to decelerate the vehicle, then energy is recovered, but the deceleration rate is limited by maximum recuperation capability
Solution Approach 1:
The braking process is segmented into two distinct phases: a first period using regenerative braking alone at a first deceleration rate, and a second period using friction brakes at a second deceleration rate. This segmentation allows the system to optimize energy recovery during the first phase while achieving the required minimum distance through the second phase, resolving the contradiction between limited regenerative deceleration capability and the need for effective distance reduction.
2Length of moving object
If friction brakes are used to achieve minimum distance, then stopping distance is reduced, but energy recovery is minimized
Solution Approach 1:
The system performs preliminary regenerative braking during the first period to recover energy before transitioning to friction brakes. By maximizing energy recovery upfront through regenerative braking while the vehicle has higher speed and greater kinetic energy available, the system reduces the subsequent reliance on friction brakes, thereby achieving both energy recovery and distance reduction goals.
3Force
If regenerative braking power exceeds maximum recuperation capability, then deceleration demand is high, but excess energy cannot be recovered
Solution Approach 1:
The system applies partial regenerative braking at maximum recuperation capability during the first period, accepting that this is insufficient to achieve the full required deceleration. The remaining deceleration demand is then satisfied by friction brakes during the second period. This partial application of regenerative braking recovers the maximum possible energy without exceeding system capabilities, while friction brakes compensate for the shortfall in deceleration performance.
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 method effectively reduces the distance to a forward detected object while minimizing energy loss and ensuring safety by leveraging both regenerative and friction braking, even when initial regenerative braking power exceeds the maximum electric powertrain capability.
Implementation Method 1
During regenerative braking, a generator may be operated to convert the kinetic energy of the vehicle into electrical energy
Implementation Method 2
decelerate the vehicle at a second rate during a second period, following the first period, via the friction brakes
Data Source
AI summary
A vehicle system includes a controller that is programmed to, in response to a speed differential between the vehicle and a forward detected object, decelerate the vehicle at a first rate during a first period via regenerative braking alone and decelerate the vehicle at a second rate during a second period, following the first period, to reduce a distance to the forward detected object from an initial distance to a minimum distance.