ESC Braking System Low-Temperature Actuator Control
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Solution Overview
Problem
In ESC integrated braking systems, the increased viscosity of brake fluid at low temperatures leads to delayed pressure transfer and degraded braking performance, particularly during emergency braking or when regenerative braking is lost, compromising driver safety and requiring additional costly components like heating wires or inefficient heat generation methods.
Innovation Solution
A method that involves a control unit to check the temperature state and adjust the duty cycle of the hydraulic control valve and motor current to maintain or increase the temperature of the actuator, applying a magnetic flux contributing current to maintain valve operation and adjust pressure accordingly, ensuring optimal brake fluid viscosity and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brake fluid is used in low temperature conditions, then the braking system can operate, but the viscosity of brake fluid increases causing delayed pressure transfer and degraded braking responsiveness
Solution Approach 1:
The patent changes the temperature parameter of the brake fluid by using motor heat generation to warm the actuator and brake fluid. The control unit adjusts motor operating parameters (current, voltage, duty cycle) to generate heat that raises the brake fluid temperature from low operating temperature to an optimal range, thereby reducing viscosity and improving responsiveness.
Solution Approach 2:
The motor serves dual functions: driving the master cylinder piston and generating heat to warm the brake fluid. The heat generated during normal motor operation is utilized to maintain brake fluid temperature, making the system self-heating without requiring external heating components.
2Reliability
If heating wires are added to hydraulic pipes to lower brake fluid viscosity, then braking responsiveness improves, but system cost increases due to additional parts
Solution Approach 1:
The motor's inherent heat generation capability is utilized to warm the brake fluid, making the system self-heating. This eliminates the need for separate heating wires or thermal management components, reducing system complexity while maintaining braking responsiveness.
Solution Approach 2:
The motor performs multiple functions: driving the master cylinder piston for brake actuation and simultaneously generating heat to maintain brake fluid temperature. This multi-functionality eliminates the need for dedicated heating components.
3Reliability
If DC current is applied to motor to heat the motor for compensating viscosity, then brake fluid viscosity is lowered, but heat generation is not continuous when driver has steering intention
Solution Approach 1:
The control unit continuously monitors brake fluid temperature and motor operating conditions, dynamically adjusting motor current and duty cycle to maintain optimal temperature. This feedback control ensures continuous heat generation whenever temperature drops, regardless of driver steering intentions or brake application status.
Solution Approach 2:
The motor operating parameters (current, voltage, duty cycle) are dynamically adjusted based on real-time temperature conditions. The system transitions between different operating modes (brake application, steering, idle) while maintaining continuous heat generation capability through parameter optimization.
4Reliability
If target pressure is set high when vehicle stops to increase actuator temperature, then viscosity is lowered, but heat generation is not possible while vehicle travels
Solution Approach 1:
The system dynamically adapts motor operating parameters based on vehicle state (moving or stopped). During vehicle travel, the motor operates at optimized current and duty cycle to generate heat continuously. When vehicle is stopped, high target pressure settings maintain temperature. This dynamic adaptation ensures heat generation effectiveness in all operating conditions.
Solution Approach 2:
The control unit changes motor operating parameters (current, voltage, duty cycle) and target pressure settings based on vehicle state and temperature conditions. These parameter changes enable continuous heat generation during travel and effective temperature maintenance during stops.
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 effectively lowers brake fluid viscosity at low temperatures, enhancing braking responsiveness and pedal feel, ensuring consistent braking force according to the driver's intention while reducing the need for additional components and improving safety.
Implementation Method 1
a method of compensating for viscosity by applying a DC current to a motor to heat the motor
Implementation Method 2
pressure generated in a master cylinder is transferred to wheels through an inlet valve with an orifice
Data Source
AI summary
A method for controlling an ESC integrated braking system including: checking, by a control unit, whether a brake is in an on state or a standby state as the braking system is activated; checking, by the control unit, whether a current temperature value is in a low temperature state lower than specified reference temperature; and controlling, by the control unit, a current duty for driving a hydraulic control valve and a current component of a motor for driving a master cylinder according to the state of the brake and whether the current temperature value is in the low temperature state.