External Fuel Rail Sensor for Accurate Viscosity Detection

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Solution Overview

Problem

Existing fuel sensors for internal combustion engines face challenges in accurately detecting fuel characteristics, especially in multi-cylinder engines and systems with fuel heaters, due to complexity, cost, and performance issues related to placement and heat exposure.

Innovation Solution

A fuel detection device with a piezoelectric bender sensor is positioned externally near the fuel rail, allowing for accurate detection of fuel characteristics at consistent pressure levels, independent of the number of cylinders, and is designed to withstand high pressures and potential heat exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor is arranged near the tank to detect fuel characteristics, then the sensor can detect fuel properties, but false readings occur due to liquid stratification caused by density differences between different fuels and water

Engineering Contradiction:
Improvefuel characteristic detection accuracyVSAvoidreading accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent moves the sensor from a vertical arrangement near the tank (where stratification occurs) to a horizontal arrangement in the fuel rail (where fuel is well-mixed). This spatial repositioning in a different dimension of the fuel system eliminates the stratification problem while maintaining detection capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If one sensor per cylinder is used in multi-cylinder engines, then accurate injection adjustment is achieved, but device complexity and cost increase significantly

Engineering Contradiction:
Improveinjection adjustment accuracyVSAvoidsensor quantity and system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a single sensor in the common fuel rail that serves all cylinders simultaneously. The sensor detects fuel characteristics at the common supply point, providing universal measurement data that the control system uses to adjust injections for all cylinders, eliminating the need for multiple individual sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the detection function for all cylinders into a single sensor location (the fuel rail). Instead of having separate sensors for each cylinder, the system merges the detection point to where all fuel lines converge, allowing one sensor to monitor the fuel supply for the entire engine.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a sensor is placed close to the engine, then detection is performed at the point of use, but the sensor becomes overheated by fuel heaters causing reading errors

Engineering Contradiction:
Improvedetection accuracy at injection pointVSAvoidheat exposure to sensor
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses the fuel rail itself as an intermediary medium. The sensor is placed in the fuel rail which is thermally isolated from the engine block and heaters. The fuel rail acts as a buffer that delivers fuel to the engine while protecting the sensor from direct heat exposure, allowing accurate detection without overheating.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Volume of moving object

If a sensor is built into the injector, then space is saved and detection is integrated, but manufacturing becomes difficult and expensive

Engineering Contradiction:
Improvesensor size and space utilizationVSAvoidsensor manufacturing complexity
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent extracts the sensor from the injector assembly and relocates it to the fuel rail. This separation allows the sensor to be a standalone component with standard dimensions, making it easier to manufacture and replace. The sensor is taken out from its previously integrated position where it would have constrained its size and complicated manufacturing.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The solution provides reliable and accurate detection of fuel properties, such as viscosity and density, without altering the fuel delivery system, and is cost-effective by simplifying installation and reducing the need for multiple sensors, while maintaining stability and accuracy across varying engine conditions.

Implementation Method 1

A fuel detection device with a piezoelectric bender sensor is positioned externally near the fuel rail, allowing for accurate detection of fuel characteristics

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2809942B1Device and/or duct for detecting fuel fed to an internal combustion engine
Publication Date: 2020.01.01 ELTEK SPA
  • EP2809942B1 patent drawingFigure 1
  • EP2809942B1 patent drawingFigure 2
  • EP2809942B1 patent drawingFigure 3

AI summary

The invention relates to a device for detecting fuel fed to an internal combustion engine. In particular, the device is equipped with removable means for fastening it to an associated duct, so that it can be installed in "fuel rails" for high-pressure fuel supply as used in fuel injection engines.