Gaseous Fuel Injection Control for Combustion Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gaseous-fuelled engines face variability in fuel injection due to in-cylinder pressure and mass density differences, leading to inefficiencies and unstable combustion, especially under high load conditions, and require modifications to accommodate higher exhaust gas recirculation rates which slow combustion.
Innovation Solution
An operating method for gaseous-fuelled engines that adjusts fuel injection pressure and pulsewidth based on engine parameters like state, load, speed, and temperature, using a negative rate limiter to maintain sonic velocity of the fuel jet and prevent fuel venting, while employing a pilot fuel for ignition assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If gaseous fuel is injected at lower pressures compared to diesel fuel, then energy required for fuel atomization is reduced, but fuel injection variability increases due to in-cylinder pressure and mass density differences
Solution Approach 1:
The patent dynamically adjusts fuel injection parameters (pressure, pulsewidth, timing) based on real-time engine operating conditions including in-cylinder pressure, temperature, and mass density variations. This allows the system to maintain reliable fuel injection despite using lower injection pressures than diesel engines, compensating for gaseous fuel's lower mass density and pressure variability through active parameter optimization.
2Object-generated harmful factors
If exhaust gas recirculation rate is increased to reduce NOx emissions, then combustion stability deteriorates due to slower combustion rate
Solution Approach 1:
The system compensates for the slowing combustion effect of high EGR rates by dynamically adjusting fuel injection parameters including increasing injection pressure, optimizing pulsewidth, and adjusting timing. These parameter changes maintain combustion stability even when 30-50% exhaust gas is recirculated, enabling the system to achieve low NOx emissions without sacrificing combustion reliability.
Solution Approach 2:
The patent employs feedback control mechanisms that monitor combustion characteristics and adjust fuel injection parameters in real-time based on actual combustion performance. This closed-loop control ensures combustion stability is maintained under varying EGR rates by continuously optimizing injection parameters响应 to measured combustion outcomes.
3Object-generated harmful factors
If gaseous fuel is used instead of diesel fuel, then emissions are reduced and fuel cost decreases, but additional ignition assistance devices are required
Solution Approach 1:
The patent utilizes the engine's existing compression heating and combustion processes to self-ignite the gaseous fuel, eliminating or minimizing the need for separate ignition assistance devices. By optimizing injection timing and pressure to ensure proper fuel-air mixing and utilization of compression heat, the system achieves reliable ignition without requiring additional glow plugs, ignition coils, or complex pilot fuel systems.
Data Source
AI summary
An engine operating method and a direct injection gaseous fuelled system directly injects a gaseous fuel into a combustion chamber during a compression stroke, commands gaseous fuel injection pressure to a target value that is determined as a function of at least one pre-selected engine parameter, measures actual gaseous fuel injection pressure and adjusts fuel injection pulsewidth to correct for differences between the target value and the actual gaseous fuel injection pressure to thereby inject the desired mass quantity of gaseous fuel as determined from an engine map.