Hybrid Brake Torque Splitting for Pump Wear Reduction
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Solution Overview
Problem
Existing vehicle braking systems, particularly those using piston pumps in ESP systems, face limitations in fine adjustment of brake pressure and reduced service life due to frequent, minor braking interventions from ACC and cruise control systems, leading to unpleasant driving behavior and pump wear.
Innovation Solution
The method divides total braking torque between a pump system and an electric machine operating as a generator, allowing for precise and continuous control of braking torque, reducing the need for frequent pump activation and extending pump service life by using the electric machine to generate recuperation braking torque, which complements the pump system's braking torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piston pump is used to generate braking pressure in ESP systems, then braking pressure can be provided, but fine adjustment of brake pressure is not possible and the pump experiences heavy wear from frequent activation
Solution Approach 1:
The braking torque is segmented into two components: pump system braking torque and recuperation braking torque. The electric machine handles the recuperation braking torque, allowing the pump system to operate less frequently and reducing wear, while the pump system provides the base braking pressure.
Solution Approach 2:
The patent replaces part of the mechanical pump-based braking system with an electric machine that operates as a generator for recuperation braking. This substitution allows for continuous and precise control of braking torque without the wear issues associated with frequent pump activation.
2Ease of operation
If the pump is activated frequently by ACC control system for minor braking torques, then braking control is achieved, but the service life of the pump is reduced and driving behavior becomes unpleasant
Solution Approach 1:
The braking torque requirement is divided between the pump system and the electric machine. The electric machine absorbs frequent minor braking torque adjustments, allowing the pump system to remain inactive during these operations, thereby extending its service life while maintaining responsive braking control.
Solution Approach 2:
The patent changes the operational parameters by introducing an electric machine that can rapidly adjust braking torque without mechanical wear. This allows the system to respond to frequent ACC control demands without activating the pump, changing from a pump-centric operation to a hybrid electric-machine-centric operation for minor adjustments.
3Measurement precision
If the electric machine is used alone to provide all braking torque, then continuous precise control is achieved, but the system cannot handle large braking torque requirements efficiently
Solution Approach 1:
The patent merges the advantages of both the pump system and the electric machine by combining their braking torque outputs. The pump system provides high-power base braking torque, while the electric machine adds precise continuous control capability, achieving both high power capacity and precise control.
Solution Approach 2:
The electric machine serves multiple functions: it provides recuperation braking torque for energy recovery, handles frequent minor braking adjustments, and supplements the pump system to achieve total braking torque requirements, making it a multi-functional component that addresses both precision and power needs.
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 enhances the service life of the pump system while providing a more pleasant driving experience without increasing system complexity, allowing for flexible and precise control of braking torque, reducing pump wear, and enabling efficient operation of both the pump and electric machine.
Implementation Method 1
the electric machine is operated as a generator in order to convert kinetic energy into electrical energy through recuperation
Implementation Method 2
The pumping system includes a pump that generates braking pressure for a friction brake
Data Source
Figure 1
AI summary
The invention pertains to a method for the combined control of an electrical machine and a pump system with a pump provided for producing a brake pressure. The method comprises the steps of: producing a total braking torque to be applied by the electric machine and the pump system; producing a pump system braking torque for acting on the power take-off by way of the pump system; and producing a recuperation braking torque for acting on the power take-off by way of the electrical machine. The pump system braking torque and the recuperation braking torque act at the same time and in common on the power take-off and the total braking torque is equal to the sum of the pump system braking torque and the recuperation braking torque. The invention further relates to a control device for carrying out the method according to the invention.