Fuel Injector Leak Detection Using Isolated Pressure Response

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Solution Overview

Problem

Existing fuel injection systems in combustion engines struggle to accurately identify which fuel injectors are leaking and the extent of their leakage, leading to sub-optimal combustion and excessive fuel consumption, as replacing all injectors is costly and inefficient.

Innovation Solution

A system and method using a PID controller to isolate each fuel injector, determine primary and baseline integral responses, and compare these responses to identify and quantify leaks, allowing selective replacement of faulty injectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all fuel injectors are replaced to mitigate leakage, then the fuel injection system reliability is improved, but the cost and complexity of repair increases significantly

Engineering Contradiction:
Improvefuel injection system reliabilityVSAvoidrepair complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the fuel injection system into individual injector units, each with its own isolation valve. This segmentation allows the system to isolate and test individual injectors rather than treating the entire system as a single unit, enabling targeted repair of only the leaking components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces isolation valves as intermediary components between the fuel rail and each injector. These valves enable selective disconnection of individual injectors from the fuel supply, allowing the system to control fuel flow to specific injectors and perform isolated leak testing without affecting other injectors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If fuel rail pressure is increased to baseline pressure for accurate leak detection, then the measurement precision of leak rate is improved, but the energy consumption increases

Engineering Contradiction:
Improveleak rate measurement precisionVSAvoidfuel pump energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary actions by first establishing a baseline pressure level and measuring the integral response at this reference condition. This preliminary measurement creates a reference point that allows subsequent leak detection to be performed with smaller pressure increments, reducing the total energy required while maintaining measurement accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes changes in pressure parameters and integral response values to detect leaks. By monitoring the integral response of the PID controller at different pressure levels and comparing against baseline values, the system can identify leaks without necessarily maintaining high pressure continuously, thus reducing energy consumption while preserving detection precision.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the PID controller integral response is monitored continuously, then the detection speed of leaking injectors is improved, but the complexity of the control system increases

Engineering Contradiction:
Improvedetection speedVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements feedback by continuously monitoring the integral response of the PID controller and using this information to detect leaks. The system feeds back the integral response values to the control unit, which compares them against baseline values to identify leaking injectors, enabling rapid detection without requiring complex additional sensing infrastructure.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4390104B1A system and a method for determining fuel injector leak
Publication Date: 2026.02.25 VOLVO TRUCK CORP
  • EP4390104B1 patent drawingFigure 1~3
  • EP4390104B1 patent drawingFigure 4~5

AI summary

A method of determining fuel leak of fuel injectors 2a, 2b of an injection system of a combustion engine, said method comprising determining a baseline pressure based on a predetermined integral response threshold and for each fuel injector 2a, 2b determine a primary reference integral response by fluidly isolating the respective fuel injector 2a, 2b and obtaining the associated primary reference integral response by obtaining the current integral response while running the engine at the baseline pressure with the respective fuel injector 2a, 2b fluidly isolated.