ABS Modulator Fast Fill Solenoid Reduces Brake Pedal Travel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power-assisted braking systems face challenges in reducing initial brake pedal travel and improving brake response time, which affects both safety and ergonomic aspects, particularly during the initiation of braking when fluid displacement occurs, leading to a loss of pedal feel and increased response time.
Innovation Solution
The integration of a solenoid into the low-pressure accumulator of the antilock braking system (ABS) to enable a fast fill of the brake system upon brake application, utilizing a toggle linkage mechanism to efficiently displace fluid into the brake system with reduced force and electrical demand, maintaining the original ABS functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional antilock braking system is used, then the ABS functionality is maintained, but the initial brake pedal travel is increased and brake response time is delayed
Solution Approach 1:
The patent applies preliminary action by pre-positioning hydraulic fluid in the accumulator chamber before brake application. When the driver presses the brake pedal, the solenoid valve rapidly opens and the pre-positioned fluid is immediately discharged into the brake system, eliminating the delay that would otherwise occur while waiting for fluid to flow from the master cylinder. This preliminary preparation of fluid in the accumulator directly reduces both initial pedal travel and brake response time.
Solution Approach 2:
The patent introduces an intermediary component - the accumulator with solenoid valve - positioned between the master cylinder and brake calipers. This intermediary stores and rapidly releases hydraulic fluid, mediating the fluid delivery process to overcome the slow direct flow from the master cylinder. The accumulator acts as a buffer that can quickly supply fluid to multiple brake calipers simultaneously, improving response time without affecting the ABS control functionality.
2Stress or pressure
If hydraulic fluid is rapidly displaced from the master cylinder, then brake pressure is applied, but pedal feel is degraded due to lost travel
Solution Approach 1:
The accumulator serves as an intermediary that decouples the master cylinder from the brake calipers. It absorbs the rapid fluid displacement from the master cylinder and delivers it in a controlled manner to the calipers, preventing the direct transmission of harsh pressure changes to the pedal. This maintains brake pressure application while preserving pedal feel by smoothing the pressure transition.
Solution Approach 2:
By pre-positioning fluid in the accumulator, the system prepares the hydraulic pressure in advance. When the brake pedal is pressed, the fluid is already positioned to be rapidly delivered, which reduces the travel distance the pedal must move to achieve brake pressure. This preliminary fluid positioning improves both pedal feel and response time by reducing the 'lost travel' distance.
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 solution reduces brake response time and initial brake pedal travel, enhancing the responsiveness of the brake pedal feel while maintaining the accumulator's original functionality and reducing the solenoid's force and electrical current requirements under high pressure.
Implementation Method 1
A solenoid has an armature reciprocable along a solenoid axis disposed generally orthogonally to the bore axis in response to solenoid energization
Implementation Method 2
there is a mechanical coupling in the form of a toggle linkage mechanism between the solenoid armature and the piston assembly operable to transmit armature motion induced by solenoid energization to the piston assembly expelling pressure fluid from the chamber to the vehicle braking system
Implementation Method 3
a brake fluid accumulator for a vehicle braking system which is operable in a passive mode to receive fluid from and return fluid to the vehicle braking system
Data Source
AI summary
An adaptation to a vehicle antilock braking system modulator to increase the initial displacement of the master cylinder, provide quicker system response and improved pedal feel. A solenoid assembly is added to the non fluid side of each of the low pressure accumulators in the ABS modulator. Upon the operator initiation of a brake apply, the solenoids are energized to immediately push upon the sump pistons and inject fluid from the low pressure accumulators into the brake system. This extra “shot” of fluid decreases the amount of fluid that the master cylinder delivers to the brake system. This improves pedal feel as it reduces the required initial pedal travel for a given brake system displacement. The low pressure accumulator pistons are spring balanced to ensure retention of fluid between brake applies and to allow normal ABS operation. During ABS operation, the low pressure accumulator displacer solenoids are de-energized to allow effective operation. The holding force (electrical current) of the displacer solenoids can be reduced by using a toggle linkage apply mechanism.