Pilot Fuel Injection Control for NOx Stabilization in Supercharged Engines
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Solution Overview
Problem
Supercharged engines using gas as fuel face challenges in minimizing NOx emissions fluctuations, which can impact the efficiency of Selective Catalytic Reduction (SCR) units, despite existing control methods for pilot fuel injection.
Innovation Solution
An engine control unit connected with a pilot fuel injector and a charge air sensor adjusts pilot fuel injection based on engine operating conditions and supercharged air pressure to maintain NOx concentration within specific limits, reducing fluctuations and enhancing SCR unit efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If pilot fuel injection is controlled to minimize NOx emissions, then NOx emissions are reduced, but NOx emissions fluctuation increases which impacts SCR unit efficiency
Solution Approach 1:
The control unit receives charge air pressure signals from a sensor and uses this feedback to dynamically adjust the pilot fuel injection timing. The system compares actual charge air pressure with reference values and modifies injection timing accordingly to maintain stable NOx emissions while minimizing overall NOx output, thus resolving the contradiction between emission reduction and emission stability.
Solution Approach 2:
The invention dynamically adjusts the timing of pilot fuel injection based on real-time charge air pressure conditions. By making the injection timing variable rather than fixed, the system adapts to changing engine operating conditions, maintaining stable NOx emissions levels while achieving low overall emissions, thereby resolving the contradiction between minimizing emissions and stabilizing emissions fluctuations.
2Object-generated harmful factors
If SCR unit is used to reduce NOx emissions, then NOx emissions are reduced, but SCR unit efficiency decreases when NOx concentration fluctuates
Solution Approach 1:
The system performs preliminary adjustment of pilot fuel injection timing based on predicted charge air pressure conditions. By proactively optimizing the injection timing before combustion occurs, the system pre-stabilizes the combustion process to produce consistent NOx emissions, ensuring stable input to the SCR unit and maintaining its high efficiency in reducing NOx emissions.
Solution Approach 2:
The control unit continuously monitors charge air pressure and uses this feedback to adjust pilot fuel injection timing in real-time. This closed-loop control ensures that NOx emissions remain stable, which in turn maintains optimal operating conditions for the SCR unit, thereby preserving SCR unit efficiency while achieving effective NOx reduction.
3Power
If charge air pressure increases, then engine power increases, but NOx concentration increases
Solution Approach 1:
The invention changes the timing parameter of pilot fuel injection in response to charge air pressure variations. When charge air pressure increases (indicating higher engine power output), the system adjusts the injection timing to optimize combustion efficiency while controlling peak combustion temperatures, thereby limiting NOx concentration formation despite the increased power output and associated higher oxygen availability and temperatures.
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
The solution effectively stabilizes NOx emissions in exhaust gases, improving the operational efficiency of SCR units and minimizing NOx oscillations, thereby reducing overall NOx emissions in supercharged engines.
Implementation Method 1
A pilot fuel injector is connected with the engine control unit for controlling pilot fuel injection
Implementation Method 2
The SCR unit is arranged to reduce NOx emissions in exhaust gas
Implementation Method 3
The arrangement comprises a charge air sensor that is connected with the engine control unit
Implementation Method 4
The engine control unit comprises an adjustment unit that is arranged to receive charge air reference data signals and signals from the charge air sensor, and also to form an adjustment signal
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention enables a SCR unit to run more efficiently. The inventive arrangement comprises an engine control unit (13), a SCR unit(12)and a pilot fuel injectors (10). The engine control unit is connected with the pilot fuel injector for controlling pilot fuel injection. Further, the arrangement comprises a supercharged air sensor(14) that is connected with the engine control unit. The engine control unit comprises an adjustment unit that is arranged to receive supercharged air reference data signals and signals from the charged air sensor(14), and also to form an adjustment signal. The adjustment signal is arranged to adjust the control of the pilot fuel injector.