Dual-Fuel Engine Liquid Fuel Injection Timing
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Solution Overview
Problem
Existing internal combustion engine systems using a diesel-type dual-fuel method face challenges in reducing the generation of nitrogen oxides and the presence of uncombusted hydrocarbons during gas fuel combustion.
Innovation Solution
An engine system and combustion method that involves supplying air and gas fuel to a combustion chamber, where a liquid fuel is injected to ignite the gas fuel, and the liquid fuel injection is controlled to occur after the flame propagation has ended following ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If subsequent injection is performed to increase flame propagation rate, then combustion rate is improved, but nitrogen oxides generation increases
Solution Approach 1:
The patent performs preliminary compression of the gas fuel and air mixture to a state that enables auto-ignition before injecting the liquid fuel. This preliminary preparation allows the combustion to start with controlled conditions, avoiding the need for aggressive subsequent injections that would increase nitrogen oxides generation.
Solution Approach 2:
The patent changes the physical state and parameters of the gas fuel by compressing it to a condition that allows auto-ignition. This parameter change enables the combustion process to proceed differently, achieving flame propagation without requiring high-rate subsequent injections that produce harmful nitrogen oxides.
2Productivity
If subsequent injection is performed to increase flame propagation rate, then combustion rate is improved, but uncombusted hydrocarbons remain
Solution Approach 1:
The patent performs preliminary compression of the gas fuel and air mixture to a state that enables auto-ignition before injecting the liquid fuel. This preliminary preparation ensures complete combustion from the start, eliminating the need for subsequent injections that would leave uncombusted hydrocarbons.
3Productivity
If liquid fuel injection is performed during flame propagation, then combustion efficiency is improved, but nitrogen oxides generation increases
Solution Approach 1:
The patent performs all necessary fuel injection and compression actions before flame propagation begins. The liquid fuel is injected and mixed with the compressed gas fuel during the compression stroke, so that by the time flame propagation starts, the mixture is already optimally prepared for complete and clean combustion.
Solution Approach 2:
The patent converts the high compression that would normally lead to high temperatures and nitrogen oxides into a benefit by using it to prepare the mixture for controlled auto-ignition. The compression energy is used to create the right conditions for clean combustion rather than directly causing harmful emissions.
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
This approach effectively suppresses the generation of nitrogen oxides and reduces the volume of uncombusted hydrocarbons, improving combustion efficiency and emissions control.
Implementation Method 1
a liquid fuel is injected into the combustion chamber thereby to ignite the gas fuel
Implementation Method 2
the injecting of the liquid fuel is performed after a flame propagation after the igniting of the gas fuel is ended
Data Source
AI summary
The present disclosure describes an engine system that can achieve at least one of the following: suppressing of generating of nitrogen oxides, and suppressing of remaining of uncombusted hydrocarbons. The engine system has a combustion chamber to which air and a gas fuel are supplied, and is configured to combust the gas fuel. The engine system includes a liquid fuel injecting unit, and a control unit. The liquid fuel injecting unit is configured to inject a liquid fuel thereby to ignite the gas fuel. The control unit is configured to control the liquid fuel injecting unit. The control unit is configured to control the liquid fuel injecting unit so that injection of the liquid fuel is performed after a flame propagation after ignition of the gas fuel is ended.