Brake Lamp Hysteresis Control for Regenerative Braking Stability
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Solution Overview
Problem
In vehicles with electric motors, the brake lamp frequently chatters due to incorrect triggering based on regenerative brake deceleration, leading to safety issues and decreased marketability, as existing systems struggle to differentiate between driver-manipulated and regenerative brake operations.
Innovation Solution
A controller system that determines the brake lamp state before entering a hysteresis period and adjusts the thresholds for deceleration-based lamp operation, using a brake lamp state setting unit, a chattering predictor, and a reference corrector to prevent chattering by setting or resetting the lamp request based on predicted pedal manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the brake lamp is operated based on regenerative brake deceleration, then fuel efficiency is improved through regenerative braking, but the brake lamp chatters frequently causing safety issues and decreased marketability
Solution Approach 1:
The controller determines the brake lamp state before entering the hysteresis period and predicts potential chattering in advance. By setting or resetting the lamp request based on predicted pedal manipulation before the chattering occurs, the system prevents brake lamp chattering while maintaining regenerative brake operation for fuel efficiency improvement.
2Productivity
If the brake lamp operates frequently based on deceleration thresholds, then regenerative brake functionality is maximized, but driver and rear driver discomfort increases due to chattering
Solution Approach 1:
The controller continuously monitors the brake lamp state and deceleration levels, using feedback from the hysteresis period determination to adjust the lamp request. This feedback mechanism allows the system to maintain high regenerative brake utilization while preventing driver discomfort by suppressing lamp chattering through state determination before entering hysteresis periods.
3Device complexity
If the brake lamp control system uses simple deceleration thresholds, then the system complexity is reduced, but the system cannot differentiate between driver-manipulated and regenerative brake operations
Solution Approach 1:
The controller acts as an intermediary that receives deceleration signals and determines whether they result from driver pedal manipulation or regenerative brake operation. By introducing the brake lamp state determination process before entering hysteresis periods, the system can differentiate between different brake sources without requiring complex additional sensors, maintaining relatively simple device complexity while achieving precise measurement of brake operation types.
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
The system effectively prevents brake lamp chattering by accurately distinguishing between driver and regenerative brake operations, enhancing safety and reducing driver and rear driver discomfort by stabilizing brake lamp behavior.
Implementation Method 1
a motor in addition to a conventional hydraulic friction brake is operated by a generator during brake, and thus, kinetic energy of a vehicle is converted into electric energy to enable the vehicle to brake, and this type is referred to as regenerative brake
Data Source
AI summary
A brake lamp control method of a vehicle is provided. The method includes determining whether a deceleration of the vehicle based on regenerative brake through the electric motor is present in a hysteresis period between an off threshold as a reference for turning off a brake lamp and an on threshold as a reference for turning on the brake lamp. When the deceleration of the vehicle is present in the hysteresis period, the method includes determining a state of the brake lamp before the deceleration of the vehicle enters the hysteresis period. In response to determining that the brake lamp is turned on or off for a reason except for the regenerative brake before the deceleration of the vehicle enters the hysteresis period, a request for turning on the brake lamp is set or reset based on the regenerative brake in response to the determined state of the brake lamp.