Simulator Valve Damped Flow Path Brake Pedal Feel
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Solution Overview
Problem
The transition between manual apply and boosted braking modes in vehicle brake systems often results in a discomfiting 'pedal drop' condition, which affects the driver's experience due to the lack of smooth fluid communication between the master cylinder and pedal simulator.
Innovation Solution
A simulator valve with a damped flow fluid path is introduced, allowing selective fluid communication between the master cylinder and pedal simulator during transition, and a free flow fluid path for boosted operation, ensuring smooth pressure regulation and feedback to the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct fluid communication is provided between master cylinder and pedal simulator, then fluid flow is unrestricted, but pedal drop occurs during mode transition causing discomfort
Solution Approach 1:
The simulator valve acts as an intermediary component between the master cylinder and pedal simulator. It includes a damped flow path with flow restriction and a free flow path that can be selectively opened. During transition, the valve restricts flow through the damped path to prevent pedal drop, then opens the free flow path to allow unrestricted flow when needed, mediating the fluid communication to achieve both smooth transition and proper brake feel.
Solution Approach 2:
The simulator valve dynamically changes its flow characteristics during operation. It transitions from a restricted flow state (damped flow path) during mode transition to an unrestricted flow state (free flow path opened) during normal operation. This dynamic adjustment of flow restriction resolves the contradiction between needing restriction during transition and needing free flow during operation.
2Reliability
If restricted fluid flow is used during transition, then pedal drop is reduced, but fluid communication efficiency decreases
Solution Approach 1:
The simulator valve serves as a mediator that provides restricted flow during transition through the damped flow path, then opens the free flow path to restore full fluid communication efficiency. This intermediary mechanism allows the system to temporarily accept reduced efficiency during transition to ensure smooth operation, then recover full efficiency when transition is complete.
Solution Approach 2:
The simulator valve operates in periodic cycles: restricting flow during transition periods, then opening free flow path during normal operation periods. This periodic switching between restricted and unrestricted flow states allows the system to prioritize transition smoothness when needed, then maximize fluid communication efficiency during stable operation.
3Productivity
If free flow path is always open, then fluid communication is efficient, but pedal drop occurs during transition
Solution Approach 1:
The simulator valve dynamically controls the free flow path, keeping it closed during transition to prevent pedal drop, then opening it to maximize fluid communication efficiency. This dynamic control of the free flow path resolution the contradiction by adjusting its state based on operational requirements rather than maintaining a fixed state.
Solution Approach 2:
The simulator valve closes the free flow path in advance during transition before full pressure equalization occurs. This preliminary action prevents pedal drop from occurring during the critical transition period, then the free flow path is opened afterward to restore efficient fluid communication when the transition is complete.
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
The simulator valve effectively controls and adjusts the brake pedal feel during the transition from manual to boosted braking, reducing pedal drop and enhancing the driving experience by maintaining consistent pressure and feedback.
Implementation Method 1
The armature, poppet, and center bore cooperatively define a damped flow fluid path therebetween. The damped flow fluid path selectively permits fluid communication therethrough from the master cylinder passage to the pedal simulator passage.
Implementation Method 2
The poppet includes a poppet bore extending longitudinally therethrough and selectively occluded by the first valve.
Data Source
AI summary
A simulator valve includes a housing having a pedal simulator passage and a master cylinder passage extending therethrough. The master cylinder passage is located longitudinally between the first housing surface and the pedal simulator passage. An armature is located at least partially within the housing for selective longitudinally reciprocating motion with respect thereto between first and second armature positions. A poppet is located within the housing for selective longitudinally reciprocating motion with respect thereto between first and second poppet positions. The poppet defines a first valve and a second valve the poppet includes a poppet bore extending longitudinally therethrough and selectively occluded by the first valve. A damped flow fluid path selectively permits fluid communication therethrough from the master cylinder passage to the pedal simulator passage. A free flow fluid path selectively permits fluid communication therethrough from the pedal simulator passage to the master cylinder passage.