Fuel Circuit Pressure Sensing for Fuel Filter Clogging Diagnosis

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Solution Overview

Problem

Existing fuel circuits in internal combustion engines lack effective methods for continuously monitoring and precisely evaluating the state of health of fuel filters, leading to potential decreased efficiency and increased wear due to impurities accumulation.

Innovation Solution

Incorporation of a fuel circuit design with a first pressure sensor upstream and a second pressure sensor downstream of the fuel filter, along with a control unit to measure and compare fuel pressure differentials, allowing for continuous monitoring and precise evaluation of filter clogging through differential pressure measurement, enhanced by opening a pressure relief valve to increase fuel flow for more accurate diagnostics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fuel filter is installed in the fuel circuit to prevent impurities from entering the high-pressure stage and injectors, then the reliability of the pumping device and injectors is improved, but the device complexity increases due to the need for additional components and monitoring systems

Engineering Contradiction:
Improvereliability of pumping device and injectorsVSAvoidcomplexity of fuel circuit
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical monitoring systems with a simplified pressure differential measurement approach. By using pressure sensors to measure the pressure difference across the filter, the system can detect filter clogging without requiring complex mechanical indicators or multiple sensors, thus maintaining reliability while reducing overall system complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fuel filter system performs self-diagnosis through pressure differential measurement. The control unit automatically monitors the pressure difference across the filter and can trigger maintenance alerts without requiring external inspection, allowing the system to monitor its own health status and reduce the need for additional monitoring components

Inventive Principle:
Principle #25Self-service

2Reliability

If the amount of impurities captured by the filter increases over time, then the filtration effectiveness is improved, but the measurement precision of filter state deteriorates due to difficulty in detecting clogging levels

Engineering Contradiction:
Improvefiltration effectivenessVSAvoidprecision of filter state evaluation
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces difficult-to-interpret physical inspection methods with electronic pressure sensing. By measuring pressure differential across the filter using electronic sensors, the system can precisely quantify filter clogging levels regardless of the amount of impurities captured, providing continuous and accurate measurement of filter state

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control unit continuously monitors the pressure differential across the filter and provides feedback on filter health status. This feedback mechanism allows the system to track filter clogging progression over time and provide precise measurements of filter state, enabling timely maintenance decisions based on actual filter condition rather than estimated service intervals

Inventive Principle:
Principle #23Feedback

3Measurement precision

If the fuel flow through the filter is increased to improve diagnostic accuracy, then the measurement precision of differential pressure is improved, but the energy consumption increases due to higher pumping requirements

Engineering Contradiction:
Improveprecision of differential pressure measurementVSAvoidenergy consumption of pumping device
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by using a pressure relief valve to create controlled fuel flow conditions. Instead of continuously increasing fuel flow through the filter, the system uses the pressure relief valve to periodically or conditionally increase flow only when filter diagnostics are needed, achieving sufficient measurement precision while minimizing additional energy consumption during normal operation

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system changes the operating parameters of the fuel circuit by using the pressure relief valve to temporarily alter fuel flow conditions. By adjusting the pressure relief valve, the system can create optimal flow conditions for differential pressure measurement without permanently increasing the energy consumption of the pumping device, thus achieving precise measurements with minimal energy penalty

Inventive Principle:
Principle #35Parameter changes

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 continuous monitoring of fuel filter health, providing early alerts and precise clogging evaluation, facilitating timely maintenance and reducing wear on pumping devices by accurately assessing filter condition under various operating conditions.

Implementation Method 1

a first pressure sensor arranged upstream from the fuel filter

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

a second pressure sensor arranged between the fuel filter and the intake of the high-pressure stage

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 3

a control unit, which is configured to control the pumping device and the pressure relief valve, and to evaluate a differential pressure of the filter when fuel flows through the filter

Methodology Applied
Scientific EffectDifferential pressure measurement: Pressure Drop

Implementation Method 4

increasing flow through the filter above a level that is usually met under normal operating conditions, thus allowing more precise measurement of differential pressure as fuel flows through the filter

Methodology Applied
Scientific EffectFluid flow increase:

Data Source

PatentEP4682368A1Fuel circuit for an apparatus, associated apparatus and method
Publication Date: 2026.01.21 VOLVO TRUCK CORP
  • EP4682368A1 patent drawingFigure 1
  • EP4682368A1 patent drawingFigure 2~2(b)
  • EP4682368A1 patent drawingFigure 3

AI summary

This fuel circuit (30) comprises a pumping device (32) comprising a low-pressure stage (34L) and a high-pressure stage (34H), the fuel circuit (30) being configured to supply, at high-pressure, fuel (22) collected from a fuel tank (20) to injectors (16) of an engine (12), a low-pressure circuit (36L) and a high-pressure circuit (36H), a fuel filter (50), which is arranged between an outlet (352) of the low-pressure stage (34L) and an intake (353) of the high-pressure stage (34H), a fist pressure sensor (P1) arranged upstream from the fuel filter (50), and a second pressure sensor (P2) arranged between the fuel filter (50) and the intake (353) of the high-pressure stage (34H).