Fuel Pressure Waveform Analysis for Viscosity Judgment
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Solution Overview
Problem
Conventional fuel property judgment devices in fuel injection systems are slow to detect abnormalities in fuel supply pumps due to the gradual increase in fuel temperature, leading to potential impediments in fuel supply and injection, necessitating high precision temperature sensors for quick and accurate detection.
Innovation Solution
A fuel property judgment device and method that utilize a fuel pressure waveform analysis to calculate fuel density and cetane number, combined with kinematic viscosity calculations, to quickly and accurately assess fuel properties, including the use of a fuel pressure sensor to detect pressure changes and a judgment section to determine the state of fuel properties based on these calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is used to detect fuel temperature to judge fuel supply pump abnormality, then the device can detect abnormality occurrence, but the detection is slow and lacks quick responsiveness because fuel temperature increases gradually
Solution Approach 1:
The invention changes the detection parameter from temperature to fuel pressure waveform characteristics. By analyzing pressure waveform period, amplitude, and shape changes that occur when fuel viscosity increases due to inferior fuel, the system achieves quick detection without waiting for temperature to rise, thus improving detection responsiveness while maintaining measurement precision
Solution Approach 2:
The invention replaces the thermal detection method (temperature sensor) with a mechanical/pressure-based detection method. By using a pressure sensor to detect fuel pressure waveform characteristics and analyzing changes in pressure period and amplitude, the system substitutes thermal measurement with pressure-based measurement, enabling faster detection of fuel property changes
2Measurement precision
If a high precision temperature sensor is used to detect fuel temperature with quick responsiveness, then detection accuracy improves, but device complexity and cost increase
Solution Approach 1:
The invention uses a standard pressure sensor instead of a high-precision temperature sensor. The pressure sensor is less expensive and has lower precision requirements, yet it effectively detects fuel property changes by analyzing pressure waveform characteristics, thus reducing device complexity and cost while maintaining detection effectiveness
Solution Approach 2:
The invention changes the detection parameter from temperature to pressure waveform characteristics. This parameter substitution allows the use of simpler, less expensive sensors while achieving the same detection goal, thereby reducing device complexity and sensor precision requirements
3Reliability
If fuel temperature is monitored to detect fuel supply pump abnormality, then abnormality can be detected, but it takes a long time before correct detection occurs
Solution Approach 1:
The invention performs preliminary detection by continuously monitoring fuel pressure waveform characteristics before temperature rise occurs. By analyzing pressure waveform period and amplitude changes that happen early when inferior fuel is introduced, the system detects abnormalities in advance, reducing detection time delay while maintaining reliability
Solution Approach 2:
The invention replaces thermal-based detection with pressure-based detection. By using pressure waveform analysis instead of temperature monitoring, the system achieves faster detection of fuel property changes, reducing the time delay before abnormality detection while maintaining reliable detection capability
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 precise judgment of fuel properties, ensuring correct fuel conditions are maintained, thereby preventing fuel supply and injection issues by using a combination of fuel pressure waveform analysis, density, and cetane number calculations to assess kinematic viscosity.
Implementation Method 1
a fuel passage sensor that detects a fuel pressure of the fuel in the fuel passage
Implementation Method 2
a speed of a fuel pressure wave which forms the waveform of the fuel pressure on the basis of a period of a pulsation of the waveform of the fuel pressure
Implementation Method 3
Each of the fuel injectors has a fuel injection hole through which the fuel is injected into a corresponding cylinder
Data Source
AI summary
A fuel injection system has a common rail storing fuel, a fuel injector injecting the fuel, a fuel-passage supplying the fuel to the fuel injector, and a fuel-pressure sensor detecting a fuel pressure. An ECU acquires a waveform of a fuel pressure representing a change of a fuel pressure based on the detected fuel pressure at the fuel injection. The ECU calculates a speed of a fuel pressure wave forming the waveform of the fuel pressure based on a period of a pulsation of the waveform of the fuel pressure and a fuel passage length, and a fuel density based on the speed of the fuel pressure wave. The ECU further calculates a fuel cetane number, and a kinematic viscosity of the fuel based on the fuel density and the fuel cetane number. The ECU judges fuel properties based on the kinematic viscosity of the fuel.