CNG Fill Hose Interlock for Ignition Lockout Safety
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Solution Overview
Problem
The existing technologies do not effectively prevent a driver from starting or moving a compressed natural gas vehicle if the high-pressure gas fill system is not correctly and completely disconnected, posing a significant risk of accidents and explosions.
Innovation Solution
A multiply-redundant system and method that uses multiple electrical proximity sensors and optional mechanical microswitches to lock out the vehicle's ignition or disable its movement when the high-pressure gas fill system is not safely disconnected, providing different levels of safety based on sensor combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors and lockout mechanisms are added to prevent vehicle operation during fueling, then safety is improved, but device complexity increases
Solution Approach 1:
The safety system is divided into multiple independent sensor components (proximity sensor, microswitch, sensor array) that each monitor specific aspects of the fueling connection. This segmentation allows the complex safety function to be achieved through simpler, modular components rather than a single complex mechanism.
Solution Approach 2:
Multiple sensing mechanisms are nested within the fueling system architecture - the proximity sensor, microswitch, and sensor array are integrated at different levels of the fueling connection structure. This nesting allows comprehensive monitoring without adding excessive external complexity.
2Object-affected harmful factors
If the vehicle ignition is locked out during fueling, then accident risk is reduced, but ease of operation deteriorates
Solution Approach 1:
The system performs preliminary detection of the fueling connection status before allowing vehicle operation. The sensors continuously monitor whether the fueling hose is properly connected and disconnected, and the ignition lockout is activated in advance if unsafe conditions are detected, preventing accidents before they can occur.
Solution Approach 2:
The system provides feedback about the fueling connection status to the vehicle's ignition control system. When sensors detect that the fueling hose is still connected or improperly disconnected, the feedback signal prevents ignition, creating a safety loop that automatically responds to connection status.
Data Source
AI summary
A multiply-redundant system that prevents a driver from starting and/or moving a vehicle if a compressed natural gas fill system is not correctly and completely disconnected from the vehicle. One or more sensors in combination with one or more optional microswitches combine to lock-out the vehicle's ignition or otherwise prevent it from starting and/or moving. For different levels of safety, different combinations of sensors can be used with the lowest level having a single proximity sensor sensing the presence or absence of a high-pressure fill hose. The highest level of safety being achieved by having separate proximity sensors on the fuel fill hose fitting, the gas cap cover and a manual safety valve along with a redundant microswitch. An optional override that may be restricted as to the number of times it can be used can allow starting with a faulty sensor in order to allow maintenance.