Ammonia Engine Combustion Control via Dual Pulse Injection
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Solution Overview
Problem
Dual-fuel engines, particularly those using diesel and ammonia, face challenges in reducing nitrous oxides (NOx) and ammonia slip emissions, which are difficult to control and result in high emissions and the need for additional exhaust treatment systems like urea-based systems.
Innovation Solution
The system employs in-cylinder pressure sensing and processing to deliver precise fuel pulses, controlling the combustion phase and fuel ratios to optimize the NH3/NOx ratio, eliminating the need for high-grade urea and associated systems by utilizing ammonia slip for selective catalytic reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If dual-fuel engines use ammonia fuel to reduce carbon emissions, then fuel efficiency improves, but nitrous oxide and ammonia slip emissions increase
Solution Approach 1:
The fuel injection is segmented into multiple pulses during the compression stroke. A first pulse of diesel fuel is injected to prepare an air/fuel mixture near auto-ignition, followed by a second pulse to start combustion. This segmented injection strategy controls the combustion process to reduce harmful emissions while maintaining fuel efficiency.
Solution Approach 2:
The injection timing parameters are dynamically adjusted based on real-time cylinder pressure feedback. The system controls the timing of fuel pulses to optimize combustion characteristics, achieving a balance between fuel efficiency and emission reduction by modifying combustion parameters.
2Object-generated harmful factors
If conventional exhaust treatment systems use high-grade urea for NOx reduction, then NOx emissions decrease, but system complexity and cost increase
Solution Approach 1:
The system uses the ammonia slip naturally produced during ammonia-fuel combustion as the reductant for NOx reduction in the exhaust after-treatment system. This self-service approach eliminates the need for external urea injection systems, simplifying the exhaust treatment system while maintaining effective NOx control.
Solution Approach 2:
The ammonia slip, which is normally considered a harmful emission, is converted into a beneficial reductant for NOx reduction. The exhaust after-treatment system utilizes this free ammonia to catalytically reduce NOx, transforming a pollutant into a useful substance for emission control.
3Productivity
If precise fuel injection timing is implemented to control combustion, then combustion efficiency improves, but measurement and control difficulty increases
Solution Approach 1:
The system implements closed-loop feedback control using real-time cylinder pressure measurements from a compression stroke sensor. The measured pressure data is used to dynamically adjust fuel injection timing and duration, enabling precise combustion control while compensating for variations in operating conditions and improving combustion efficiency.
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 reduces NOx and ammonia slip emissions, improving combustion efficiency and eliminating the requirement for high-grade urea in exhaust gas treatment systems, enhancing engine performance and reducing emissions.
Implementation Method 1
a body moveable to a center position to compress at least one of a gas or a gas/liquid mixture in a compression phase
Implementation Method 2
movable from the center position by expanding combustion gasses in an expansion phase
Implementation Method 3
an exhaust after-treatment system configured to receive free ammonia present in exhaust gasses and catalyze NOx based on ammonia
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, a method performed in connection with an internal combustion engine, and the method including receiving a pressure signal from a combustion chamber pressure sensor during a first range of volumes, the first range corresponding to a portion of a compression phase, the received pressure being a first pressure, providing, based on the received pressure signal, a first pulse of fuel at a first position of the body during the compression phase, and providing, based on the received pressure signal a second pulse of fuel at a second position of the body during the compression phase.