Regenerative Braking Torque Control for Vehicle Fuel Efficiency
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Solution Overview
Problem
Existing regenerative braking systems in vehicles are not optimized for varying traffic situations and vehicle velocities, leading to suboptimal fuel efficiency and comfort, as they apply braking torque regardless of resistance conditions such as slope, air resistance, and internal losses.
Innovation Solution
A method and device that dynamically adjust regenerative braking based on continuously determined resistance to forward travel, including slope, air resistance, rolling resistance, and internal driveline losses, by varying the braking torque in response to changes in these factors, and considering the distance and velocity relative to a lead vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is applied at low velocities below 50 km/h when the gas pedal is undepressed, then fuel efficiency is improved through energy recovery, but vehicle comfort deteriorates due to unwanted braking torque in situations where rolling is desirable
Solution Approach 1:
The regenerative braking system dynamically adjusts its operation based on real-time detection of traffic situations and vehicle operating conditions. The control unit monitors parameters such as vehicle velocity, gas pedal position, and surrounding traffic conditions to dynamically enable or disable regenerative braking, allowing the system to adapt to changing conditions rather than applying fixed braking rules
Solution Approach 2:
The system incorporates feedback mechanisms where the control unit continuously monitors traffic situations and vehicle state, then adjusts regenerative braking application accordingly. By detecting whether the vehicle is in sparse traffic or approaching a lead vehicle, the system provides feedback-based control that prevents unwanted braking in situations where rolling would be more comfortable
2Loss of energy
If regenerative braking torque is increased to maximize energy recovery, then energy storage is improved, but driver comfort deteriorates due to more noticeable braking effects
Solution Approach 1:
The system applies partial regenerative braking action by limiting the braking torque to a maximum of 100 Nm at the gearbox input shaft. This partial action approach recovers sufficient energy to improve fuel efficiency while keeping the braking effect subtle enough to maintain driver comfort and not interfere with natural vehicle rolling
Solution Approach 2:
The regenerative braking torque is dynamically adjusted based on detected traffic situations. The control unit enables regenerative braking only when beneficial for fuel efficiency and disables it when would compromise comfort, creating a dynamic balance between energy recovery and driver experience
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 fuel consumption and enhances vehicle comfort by optimizing regenerative braking in real-time, adapting to different driving conditions and allowing for more intuitive driver interaction, while also storing energy for later use.
Implementation Method 1
The braking torque can thus be applied to the driveline by means of an electric machine, whereupon braking energy can be stored in said battery
Implementation Method 2
braking energy can be stored in said battery
Data Source
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AI summary
The invention concerns a method for comfortable and/or fuel-efficient forward travel of a motor vehicle (100), which method comprises the steps of: - regeneratively braking (s401) said motor vehicle (100); and - regeneratively braking said motor vehicle (100) following detection of deactivated depression of the gas pedal based on a continuously determined magnitude of the resistance to forward travel. The invention also concerns a computer program product comprising program code (P) for a computer (210; 220) for implementing a method according to the invention. The invention also concerns a device for comfortable and/or fuel-efficient forward travel of a motor vehicle (100) and a motor vehicle (100) that is equipped with the device.