Bellows Degradation Detection Using Hydrocarbon Sensor

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Solution Overview

Problem

Fuel systems with pressure-less fuel tanks and variable volume devices, such as bellows, face challenges in detecting degradation or leaks without additional specialized components, leading to potential increased evaporative emissions and operator frustration due to lengthy depressurization times and higher costs.

Innovation Solution

A system and method that utilize a hydrocarbon sensor coupled to the atmospheric port of the bellows via a vent line, with a controller monitoring the sensor output to detect degradation or leaks in the bellows, allowing for effective diagnosis without additional components and ensuring compliance with emissions regulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a bellows is used to vent fuel vapors via an atmospheric port, then depressurization time and system cost are reduced, but degradation in the bellows results in undetected increased evaporative emissions

Engineering Contradiction:

Improvedepressurization timeVSAvoiddetection of bellows degradation

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The hydrocarbon sensor positioned in the vent line serves multiple functions: it monitors evaporative emissions during normal operation and detects bellows degradation during diagnostic modes. This multi-functionality allows the system to maintain reduced depressurization time while enabling reliable detection of bellows degradation without adding specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes the operational parameters of the bellows by pressurizing it during diagnostic modes to accelerate vapor flow through potential degradation paths. This parameter change (from normal venting to pressurized diagnostic mode) enables the hydrocarbon sensor to detect bellows degradation that would not be apparent during normal operation.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If additional specialized components are installed to detect bellows degradation, then detection reliability is improved, but system cost increases

Engineering Contradiction:

Improvedetection of bellows degradationVSAvoidsystem cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its existing hydrocarbon sensor and vent line infrastructure to perform self-diagnosis of bellows degradation. By activating the fuel pump to pressurize the bellows and monitoring the hydrocarbon sensor output, the system enables its own component degradation detection without requiring external specialized diagnostic equipment.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If the fuel pump is activated to pressurize the bellows, then diagnostic accuracy is improved, but energy consumption increases

Engineering Contradiction:

Improvedegradation detection accuracyVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The fuel pump is activated periodically during diagnostic modes rather than continuously. The controller activates the fuel pump for a predetermined time period to pressurize the bellows, then monitors the hydrocarbon sensor. This periodic activation achieves sufficient diagnostic accuracy while minimizing energy consumption compared to continuous operation.

Inventive Principle:

Principle #19Periodic action

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

Enables rapid and efficient detection of bellows degradation, reducing evaporative emissions and operational costs by leveraging existing vehicle components, thus facilitating a transition to less costly pressure-less fuel tank systems while maintaining compliance with emissions regulations.

Implementation Method 1

monitoring output of the hydrocarbon sensor to identify a degradation in the bellows

Methodology Applied

Scientific EffectHydrocarbon detection:

Implementation Method 2

a sealed but 'pressure-less' fuel tank with a built-in variable volume device (e.g., a bellows) that expands and contracts to relieve vacuum and pressure buildups

Methodology Applied

Scientific EffectVariable volume device expansion and contraction: Elasticity

Implementation Method 3

activating a fuel pump positioned in the fuel tank to generate fuel vapors

Methodology Applied

Scientific EffectFuel vapor generation: Evaporation

Data Source

PatentUS11651631B2Methods and systems for diagnosing degradation in pressureless fuel tank

Publication Date: 2023.05.16 FORD GLOBAL TECH LLC

AI summary

Methods and systems are provided for diagnosing leaks/degradation in a fuel system. In one example, a system for a vehicle may comprise a variable volume device disposed within a fuel tank; an atmospheric port of the variable volume device fluidly coupled to a vent line upstream of a hydrocarbon sensor housed in the vent line, the vent line coupling a fuel vapor canister to atmosphere; and a controller storing instructions for monitoring output of the hydrocarbon sensor; and generating an indication of a degradation in the variable volume device based on the monitored hydrocarbon sensor. In this way, it is possible to effectively detect a degradation/leak in the variable volume device with minimal specialized components in the fuel system.