Hybrid Vehicle Braking System with Electric Motor Support
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Solution Overview
Problem
Existing vehicle braking systems, particularly in electric and hybrid electric vehicles, face challenges in efficiently modulating brake force and energy recuperation, leading to suboptimal driving performance and range due to the limitations of hydraulic and electric motor interactions.
Innovation Solution
A method and system that combine hydraulic and electric motor braking forces, with the electric motor supporting and modulating the hydraulic brake force, allowing for rapid torque changes and enhanced energy recuperation by controlling the brake forces through a controller, enabling the electric motor to take over during high-frequency changes and the hydraulic system during low-frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the hydraulic braking system is used alone for braking intervention, then the system structure is simple, but the response speed is slow and energy recuperation is limited
Solution Approach 1:
The patent combines the hydraulic braking system with the electric motor into a unified braking system. The electric motor operates in generator mode during braking to provide both deceleration force and energy recuperation, while the hydraulic system provides supplementary braking force. This merging allows the system to achieve fast response characteristics from the electric motor while maintaining the robust braking capability of the hydraulic system, resolving the contradiction between response speed and system complexity.
2Loss of energy
If the electric motor operates alone for braking, then energy recuperation is maximized, but the braking force modulation capability is insufficient
Solution Approach 1:
The electric motor is designed to perform multiple functions: it acts as a drive motor during acceleration, operates as a generator for energy recuperation during braking, and provides adjustable braking force through controlled generator torque. The hydraulic system complements this by providing additional braking force when needed. This multi-functionality allows the system to maximize energy recuperation while maintaining versatile brake force modulation capability across different driving conditions.
3Ease of operation
If the hydraulic braking system provides all braking force, then the system is simple to control, but the driving experience deteriorates due to stuttering and noise
Solution Approach 1:
The system dynamically adjusts the distribution of braking force between the electric motor and hydraulic system based on real-time driving conditions. During ABS or ESP interventions, the electric motor provides smooth, continuously adjustable braking force that complements the hydraulic system, reducing stuttering and noise. The controller dynamically modulates the generator torque to maintain optimal braking performance while improving driver comfort and reducing harmful vibrations and noises.
4Reliability
If the electric motor supports the hydraulic braking system during ABS/ESP interventions, then braking performance improves, but the control complexity increases
Solution Approach 1:
The control system continuously monitors wheel speed, vehicle speed, and braking force requirements, and adjusts the electric motor's generator torque accordingly. During ABS or ESP interventions, the controller receives feedback from wheel speed sensors and dynamically modulates the electric motor's braking contribution to maintain optimal braking performance. This feedback control ensures reliable braking performance while managing control complexity through coordinated control of the electric motor and hydraulic system.
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 results in improved dynamic driving performance, increased energy recovery, reduced noise and brake wear, and a more uniform braking experience, allowing for a greater electric vehicle range and simpler hydraulic system design.
Implementation Method 1
the electric motor operating as the generator... rotatory energy of at least one wheel is stored as electrical energy in a suitable energy store via the electric motor operating as the generator
Implementation Method 2
a hydraulic braking system, which is operated by the driver and which generates a brake force in a modulating manner
Data Source
AI summary
A method for braking a vehicle, a braking intervention being performed on at least one wheel of the vehicle, a total brake force for the braking intervention being generated by a hydraulic unit in the vehicle on the one hand, and, on the other hand, by at least one electric motor assigned to the one wheel, which at all times supports the brake force generated by the hydraulic unit, the total brake force being generated by modulating a brake force generated by the hydraulic unit and by modulation of the brake force generated by the electric motor on the at least one wheel, the brake force of the hydraulic unit and the brake force of the electric motor being added to yield the total brake force, and an amount of the particular brake force being controlled by a controller as a function of a driving situation of the vehicle.