Coordinated Engine and SCR Control for NOx Compliance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Diesel engines face challenges in reducing nitrogen oxides (NOx) emissions while efficiently managing fuel consumption, as existing SCR systems often require trade-offs between NOx reduction and fuel efficiency, with current methods not effectively optimizing both within compliance limits.
Innovation Solution
A method and apparatus that coordinate the control of engine intake oxygen concentration and fuel consumption to achieve a targeted NOx output by determining the relationship between fuel consumption and NOx production, adjusting reductant storage in the SCR catalyst, and modulating reductant injection and oxygen intake to optimize SCR performance and reduce fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If SCR systems are used to reduce NOx emissions in diesel engines, then NOx compliance is improved, but fuel consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the intake oxygen concentration (a critical parameter) to optimize the balance between NOx output and fuel consumption. The system identifies the relationship between fuel consumption and NOx output as a function of intake oxygen concentration, then determines optimal operating points that minimize fuel consumption while maintaining NOx compliance. This involves changing the oxygen concentration parameter in the intake air to achieve targeted NOx output levels that work efficiently with the SCR system's reductant storage capacity.
2Use of energy by moving object
If intake oxygen concentration is increased to reduce fuel consumption, then fuel efficiency is improved, but NOx output increases which may exceed compliance limits
Solution Approach 1:
The patent implements feedback control by continuously monitoring the reductant storage level in the SCR catalyst (determined as current reductant stored divided by reductant storage capacity) and using this information to adjust the targeted NOx output and corresponding intake oxygen concentration. The system determines a targeted NOx output level that increases with increasing reductant stored on the SCR catalyst, then selects a targeted intake oxygen concentration to achieve this target. This closed-loop feedback mechanism ensures that fuel consumption is optimized while NOx emissions remain within compliance limits by dynamically adapting to the SCR system's current state.
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 allows for increased NOx output while minimizing fuel consumption, maintaining compliance with emissions regulations by optimizing SCR system performance and adjusting operating conditions such as engine speed, torque load, and catalyst temperature.
Implementation Method 1
SCR systems utilize a reductant, typically ammonia, and an SCR catalyst to convert the NOx
Implementation Method 2
many systems utilize an alternate compound such as urea that vaporizes and decomposes to ammonia before entering the SCR catalyst
Implementation Method 3
urea that vaporizes and decomposes to ammonia
Data Source
AI summary
The present disclosure relates to a method and apparatus to reduce fuel consumption while remaining in NOx compliance by simultaneous and coordinated control of the engine and the selective catalytic reduction (SCR) system. More particularly, the present disclosure identifies methods and apparatus to increase NOx output within a diesel engine to optimize the performance of a given SCR system while simultaneously reducing fuel consumption at a selected and targeted intake oxygen concentration.