Multi-Fuel Engine Misfire Detection via Torsional Vibration
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Solution Overview
Problem
Multi-fuel engines face challenges in achieving high gaseous fuel substitution ratios due to non-linear delivery characteristics of liquid fuel injectors, leading to limited gaseous fuel usage and potential misfires, as each injector has a unique turn down point, requiring individual tuning to ensure stable combustion across all cylinders.
Innovation Solution
A misfire monitor using torsional vibration orders from a crankshaft sensor tunes each liquid fuel injector to the lowest safe liquid fuel injection rate, allowing for high gaseous fuel substitution ratios by detecting misfires and adjusting injection rates, ensuring stable combustion across all cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the liquid fuel injection rate is reduced to increase gaseous fuel substitution ratio, then the gaseous fuel usage increases, but combustion stability deteriorates due to non-linear delivery characteristics and turn down points of injectors
Solution Approach 1:
The system dynamically adjusts liquid fuel injection parameters (injection timing, duration, quantity) based on real-time engine operating conditions to maintain optimal combustion stability while maximizing gaseous fuel substitution ratio
Solution Approach 2:
The controller continuously monitors combustion parameters and adjusts liquid fuel injection rates based on feedback from engine performance data, enabling adaptive optimization of the liquid-gaseous fuel ratio to prevent misfires while maintaining high substitution ratios
2Ease of operation
If a fixed minimum liquid fuel injection rate is used across all cylinders, then the system is simple to operate, but the gaseous fuel substitution ratio is limited by the highest turn down point among all injectors
Solution Approach 1:
The system implements cylinder-specific liquid fuel injection rates tailored to each injector's unique turn down point characteristics, allowing each cylinder to operate at its optimal liquid-gaseous fuel ratio rather than using a uniform minimum rate across all cylinders
Solution Approach 2:
The liquid fuel injection rates are dynamically adjusted for each cylinder based on real-time monitoring of combustion stability and individual injector performance, enabling the system to adaptively optimize gaseous fuel substitution ratio rather than relying on fixed conservative limits
3Quantity of substance
If individual tuning of each liquid fuel injector is performed to achieve high gaseous fuel substitution ratio, then the gaseous fuel usage increases, but the device complexity and tuning time increase
Solution Approach 1:
The system performs preliminary characterization of each injector's delivery characteristics and turn down point during initial setup or maintenance, storing this data for future reference to avoid repeated complex tuning procedures
Solution Approach 2:
The controller automatically performs adaptive tuning of liquid fuel injection rates based on real-time combustion monitoring, eliminating the need for manual individual injector tuning and reducing both complexity and tuning time while maintaining high gaseous fuel substitution ratios
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 operation at high gaseous fuel substitution ratios, such as 99% gaseous fuel and 1% liquid fuel, by individually optimizing liquid fuel injection rates, thereby improving combustion stability and efficiency across all cylinders.
Implementation Method 1
measure one or more torsional vibration orders of the engine based on signals from the crankshaft speed sensor
Implementation Method 2
determine an amplitude of the one or more torsional vibration orders, and when the amplitude is greater than a threshold amplitude, indicate misfire
Implementation Method 3
the natural gas/intake air mixture in each cylinder of the engine may be combusted in response to an injection of liquid fuel
Data Source
AI summary
Various methods and systems are provided for an engine capable of receiving liquid and gaseous fuel. In one example, cylinder misfire may be identified based on a misfire monitor. The misfire monitor may detect misfire based on signals from a crankshaft sensor.