Dual Stage Accelerator Pedal with Adjustable Spring Feedback
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Solution Overview
Problem
Drivers of electric and hybrid vehicles experience discomfort due to the unexpected application of regenerative braking, which differs from conventional vehicle deceleration, leading to increased range anxiety and discomfort.
Innovation Solution
A dual stage accelerator assembly with a spring system that provides feedback through adjustable pedal resistance, allowing the transition point between stroke stages to be set, and includes a regeneration system controller to manage regenerative braking, informing the driver through tactile feedback when battery capacity is low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is applied aggressively in EVs, then energy recovery efficiency is improved, but driver comfort and acceptance deteriorate
Solution Approach 1:
The accelerator pedal stroke is divided into multiple stages with different spring resistance characteristics. The first stage has lower resistance for comfortable initial depression, while the second stage has higher resistance to provide tactile feedback during deceleration, segmenting the pedal travel to differentiate between acceleration and regenerative braking phases
Solution Approach 2:
The variable spring resistance system provides tactile feedback to the driver based on vehicle operating conditions. During regenerative braking, the increased resistance in the second stroke stage gives the driver sensory feedback about the energy recovery process, making the invisible energy capture visible through pedal effort
2Device complexity
If a single spring system is used in the accelerator pedal, then device complexity is reduced, but the ability to provide differentiated tactile feedback for different operating conditions deteriorates
Solution Approach 1:
The spring resistance system is made dynamic and adjustable based on vehicle operating conditions. The controller modifies spring pre-load and stiffness characteristics in real-time according to factors such as battery state of charge, driving mode, and deceleration rate, allowing the same physical spring system to provide different tactile feedback for different operating scenarios
3Manufacturing precision
If the transition point between stroke stages is fixed, then manufacturing precision is improved, but adaptability to different driving conditions deteriorates
Solution Approach 1:
The system pre-configures multiple transition points and spring characteristics during manufacturing, then selectively activates appropriate configurations based on detected driving conditions. The controller can switch between pre-programmed spring rates and transition points to match different driving scenarios, combining manufacturing precision with operational adaptability
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 system reduces driver discomfort by providing clear tactile feedback during deceleration and low battery capacity alerts, enhancing the driving experience and reducing range anxiety by allowing for proactive charging and route adjustments.
Implementation Method 1
The first spring assembly is comprised of (i) a first spring, (ii) a second spring assembly that includes a second spring
Implementation Method 2
a spring compression member coupled to the linkage arm and proximate to the first end of the first spring, where during the initial stage of accelerator pedal travel corresponding to the first pedal stroke stage the spring compression member only compresses the first spring
Implementation Method 3
a first adjustment mechanism coupled to the rear spring support member which moves the support member to the first position upon receipt of a first control signal and moves the support member to the second position upon receipt of a second control signal
Data Source
AI summary
A dual stage accelerator pedal spring assembly is provided that allows the transition point between stroke stages to be set, thereby controlling pedal travel within the first stroke stage, and notifies the driver of a critical operating condition, such as a low battery pack level, via a pedal feedback system. The spring assembly, which uses two springs exhibiting different spring force, allows adjustment of the relative positions of the two springs in order to control the transition point between the first and second pedal stroke stages. The change in pedal resistance used to notify the driver of a change in a monitored vehicle characteristic is achieved by preloading one of the springs in the spring assembly.