Dual-Path Exhaust Gas Recirculation System for Diesel Engine Emission Control
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Solution Overview
Problem
Internal combustion engines, particularly diesel engines, face challenges in achieving efficient exhaust-gas processing and aftertreatment, with existing systems struggling to effectively control and mix recirculated exhaust gases with fresh air, leading to inefficiencies and increased pollutant emissions.
Innovation Solution
The implementation of a system with high-pressure and low-pressure exhaust-gas recirculation lines, equipped with valves and sensors, including pressure and temperature sensors, to precisely control the recirculation of exhaust gases, ensuring efficient mixing and cooling, and the use of an exhaust-gas flap to manage the flow, along with a particulate filter to reduce pollutants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust-gas recirculation is implemented to reduce pollutant emissions, then harmful factors are reduced, but device complexity increases due to multiple recirculation lines and control valves
Solution Approach 1:
The exhaust-gas recirculation system is segmented into two separate lines: a high-pressure EGR line branching upstream of the turbine and a low-pressure EGR line branching downstream of the turbine. Each line has its own control valve (high-pressure EGR valve and low-pressure EGR valve), allowing independent control of recirculation at different pressure stages. This segmentation enables precise control of exhaust-gas recirculation to reduce pollutants while managing system complexity through functional division.
2Measurement precision
If exhaust-gas flap is added to control low-pressure recirculation flow, then flow control precision is improved, but device complexity increases
Solution Approach 1:
The exhaust-gas flap is designed as a dynamic control element that can be actively adjusted based on operating conditions. The flap works in coordination with the low-pressure EGR valve, where the valve provides primary control and the flap provides fine-tuning and flow regulation. This dynamic control mechanism enables precise control of low-pressure recirculation flow rates across different engine operating points, improving flow control precision while using a relatively simple flap structure rather than complex multi-component actuators.
Data Source
AI summary
An internal combustion engine has a high-pressure exhaust-gas recirculation line and a low-pressure exhaust-gas recirculation line with a low-pressure exhaust-gas recirculation valve. The low-pressure exhaust-gas recirculation line branches off from the exhaust-gas system downstream of a turbine of an exhaust-gas turbocharger and opens into a fresh-air system upstream of a compressor of the exhaust-gas turbocharger. An exhaust-gas flap is disposed in the exhaust-gas system downstream from where the low-pressure exhaust-gas recirculation line branches off from the exhaust-gas system. At least one pressure sensor is disposed in the low-pressure exhaust-gas recirculation line and configured such that the at least one pressure sensor determines a pressure difference in the low-pressure exhaust-gas recirculation line between a point upstream of the low-pressure exhaust-gas recirculation valve and a point downstream of the low-pressure exhaust-gas recirculation valve. A method for operating an internal combustion engine is also provided.