Vapor Blocking Valve Leak Diagnosis Using a Single Pressure Sensor

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Solution Overview

Problem

Existing evaporative emissions systems require multiple pressure sensors to test the operability of the vapor blocking valve (VBV), increasing system complexity and cost, while regulatory requirements necessitate a cost-effective method to diagnose VBV failures.

Innovation Solution

A method and system using a single pressure sensor to test VBV operability by monitoring pressure differentials and characteristics during controlled valve positions, determining VBV functionality through comparative pressure analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two pressure sensors are used to test VBV operability, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

ImproveVBV operability diagnosis accuracyVSAvoidnumber of pressure sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The single pressure sensor is designed to perform multiple functions: it measures pressure in the vapor blocking valve circuit, measures pressure in the canister circuit, and participates in both leak detection and flow testing operations. By making the pressure sensor universal, the system eliminates the need for separate sensors while maintaining complete diagnostic capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The canister valve solenoid acts as an intermediary component that enables the single pressure sensor to access different circuit regions. By controlling the solenoid to open or close specific passages, the system redirects fluid flow and pressure signals through the single sensor, allowing it to indirectly measure conditions in both the VBV circuit and canister circuit without requiring physical presence in both locations simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If two pressure sensors are used to test VBV operability, then measurement precision is improved, but system cost increases

Engineering Contradiction:

ImproveVBV operability diagnosis accuracyVSAvoidsystem cost

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses existing components (the single pressure sensor, canister valve solenoid, and natural pressure differentials created during engine operation) to perform the VBV diagnostic function. Rather than adding dedicated diagnostic hardware, the system repurposes existing elements to provide self-diagnosis capability.

Inventive Principle:

Principle #25Self-service

3Device complexity

If a single pressure sensor is used, then device complexity is reduced, but measurement precision may deteriorate

Engineering Contradiction:

Improvenumber of pressure sensorsVSAvoidVBV operability diagnosis accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system performs periodic switching of the canister valve solenoid between open and closed states during the diagnostic sequence. This periodic action creates distinct pressure conditions at different times, allowing the single pressure sensor to capture different circuit states sequentially. By analyzing the temporal pattern of pressure readings, the system achieves diagnostic precision equivalent to having simultaneous measurements from multiple sensors.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The controller pre-establishes known pressure conditions by controlling the canister valve solenoid state before taking measurements. By preliminarily setting up specific circuit configurations (open or closed solenoid), the system ensures that the single pressure sensor encounters predictable pressure patterns that enable accurate VBV status determination.

Inventive Principle:

Principle #10Preliminary 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

Accurately diagnoses VBV operability with reduced components, maintaining system integrity and compliance with regulatory standards without unnecessary cost additions.

Implementation Method 1

monitoring pressure differentials and characteristics during controlled valve positions, determining VBV functionality through comparative pressure analysis

Methodology Applied

Scientific EffectPressure differential measurement: Pressure Gradient

Data Source

PatentUS12553406B2Evaporative emissions system vapor blocking valve leak diagnostic with a single pressure sensor

Publication Date: 2026.02.17 STONERIDGE CONTROL DEVICES INC

AI summary

A method is disclosed of testing operability of a vapor blocking valve (VBV) in a first passageway that is fluidly arranged between a fuel tank and a carbon canister. A canister valve solenoid (CVS) is arranged in a second fluid passageway that fluidly interconnects the carbon canister and an atmospheric port. The method includes obtaining a first desired pressure in the first passageway, closing the VBV, opening the CVS, monitoring a first test pressure in the first passageway with a pressure sensor, obtaining a second desired pressure in the first passageway, opening the VBV, opening the CVS, monitoring a second test pressure in the first passageway with the pressure sensor, comparing the first and second test pressures, and determining the VBV operability based upon the comparing step.