Valve Stem Pressure Regulator for Automatic Tire Inflation
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Solution Overview
Problem
Tire pressure naturally decreases over time, leading to reduced fuel economy, tire life, and vehicle handling performance, and existing Tire Pressure Monitoring Systems require driver intervention for re-inflation.
Innovation Solution
An air maintenance tire assembly with a pressurized air supply system that includes a pressure regulator, sensor, and valve mechanism to automatically maintain tire pressure by pumping air into the tire cavity through a peristaltic pumping mechanism within the tire sidewall, using a valve stem and regulator housing to control air flow based on pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Tire Pressure Monitoring System is used to warn drivers when tire pressure is low, then tire pressure can be monitored, but driver intervention is still required for re-inflation
Solution Approach 1:
The tire assembly performs self-service by incorporating an automatic air maintenance system that monitors tire pressure and replenishes air automatically without requiring driver intervention. The system uses a pressure sensor to detect low pressure conditions and activates a compressor through a control module to inflate the tire autonomously.
Solution Approach 2:
The system implements feedback control by continuously monitoring tire pressure with a sensor and using the pressure information to control the compressor operation. The control module receives pressure signals and automatically activates or deactivates the compressor based on whether pressure is below or above the threshold, creating a closed-loop automatic control system.
2Reliability
If air is continuously supplied to maintain tire pressure, then tire pressure is maintained, but energy consumption increases
Solution Approach 1:
The compressor operates periodically rather than continuously, activating only when the pressure sensor detects that tire pressure has fallen below the threshold. The control module interrupts power to the compressor when pressure reaches the threshold, creating an on-demand periodic operation that reduces energy consumption while maintaining reliable tire pressure.
3Manufacturing precision
If a pressure regulator valve is used to control air flow, then air pressure control is improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical pressure regulation mechanisms with an electronically controlled approach. The control module uses electrical signals to control the compressor operation and incorporates a simple check valve for one-way air flow control, substituting sophisticated mechanical pressure regulation with electronic control and simpler passive valve components.
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 effectively maintains tire pressure without driver intervention, enhancing fuel efficiency, tire longevity, and vehicle performance by automatically replenishing air when pressure falls below recommended levels.
Implementation Method 1
An air pumping mechanism is incorporated into a tire sidewall for pumping air into a tire cavity to maintain a tire cavity pressure above zero gauge pressure. The air pumping mechanism will compress segment by segment from an expanded diameter to a substantially reduced diameter responsive to a bending strain introduced into the tire sidewall from a rolling tire footprint.
Data Source
AI summary
An air maintenance tire assembly and method of operation includes a pressurized air supply assembly for supplying pressurized air to a tire cavity through an elongate outward projecting, valve stem passageway. An elongate centrally disposed shaft within the valve stem reciprocally moves axially in the valve stem internal air passageway between a passageway-opening axial position and a passageway-closing axial position. A pressure regulator is provided to move the elongate shaft axially between the passageway-opening and passageway-closing positions responsive to a detected air pressure level within the tire cavity.