EGR Control via Intake Charge Diluent Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines face challenges in effectively controlling exhaust gas recirculation (EGR) to reduce nitrogen oxide (NOx) emissions, as existing methods struggle to optimize the air/fuel ratio and EGR amounts dynamically based on engine operating conditions.
Innovation Solution
A method and system that determine the intake charge components, including air, fuel, and diluent (exhaust gas), using sensors and a processor-based engine control module to adjust the air/fuel ratio and EGR supply, leveraging speed/density equations and torque measurements to maintain optimal engine operation and reduce NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas recirculation is increased to reduce NOx emissions, then nitrogen oxide emissions are reduced, but engine performance and fuel efficiency deteriorate
Solution Approach 1:
The system dynamically adjusts EGR rates based on real-time operating conditions (load, speed, temperature) rather than using fixed EGR strategies. The controller continuously monitors engine parameters and modifies EGR valve positioning to optimize the balance between NOx reduction and performance maintenance across varying operational states.
Solution Approach 2:
The system changes multiple parameters simultaneously including EGR rate, injection timing, injection quantity, and air-fuel ratio to achieve NOx reduction while maintaining performance. By coordinating adjustments across these parameters, the system compensates for the performance penalty typically associated with high EGR rates.
2Object-generated harmful factors
If exhaust gas recirculation is increased to reduce NOx emissions, then nitrogen oxide emissions are reduced, but fuel efficiency deteriorates
Solution Approach 1:
The system uses feedback from oxygen sensors and engine parameters to continuously adjust EGR rates and air-fuel ratios. This closed-loop control ensures that EGR is optimized for NOx reduction while preventing excessive fuel consumption by adjusting injection quantities based on actual combustion conditions and oxygen levels in the exhaust.
Solution Approach 2:
The system coordinates changes in EGR rate with complementary adjustments in injection timing and air-fuel ratio to maintain optimal combustion efficiency. By synchronizing these parameter changes, the system achieves NOx reduction without proportionally increasing fuel consumption.
3Productivity
If air/fuel ratio is adjusted to optimize engine performance, then engine performance improves, but NOx emissions increase
Solution Approach 1:
The system uses EGR as an intermediary substance to enable high-performance combustion while preventing excessive NOx formation. By introducing inert exhaust gases into the combustion chamber, the system allows for optimized air-fuel ratios for performance while the EGR acts as a buffer that limits peak temperatures and suppresses NOx chemistry.
Solution Approach 2:
The system creates a composite charge composition combining fresh air-fuel mixture with recirculated exhaust gases. This composite mixture allows the engine to operate with air-fuel ratios optimized for performance while the exhaust gas component within the mixture suppresses NOx formation through dilution and temperature moderation.
4Object-generated harmful factors
If dynamic control of EGR and air/fuel ratio is implemented, then emission reduction and performance optimization are achieved, but control system complexity increases
Solution Approach 1:
The control system is designed to perform multiple functions using integrated algorithms that simultaneously optimize EGR rates, air-fuel ratios, injection timing, and injection quantities. This multi-functional approach consolidates what could be separate control systems into a unified controller, managing complexity while achieving comprehensive optimization of emissions and performance.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
In controlling an engine, an amount of an intake charge provided, during operation of the engine, to a combustion chamber of the engine is determined. The intake charge includes an air component, a fuel component and a diluent component. An amount of the air component of the intake charge is determined. An amount of the diluent component of the intake charge is determined utilizing the amount of the intake charge, the amount of the air component and, in some instances, the amount of the fuel component. An amount of a diluent supplied to the intake charge is adjusted based at least in part on the determined amount of diluent component of the intake charge.