Internal Combustion Engine Emission Control via Turbocharger and Fuel Injection
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Solution Overview
Problem
Compression-ignition engines face challenges in controlling exhaust emissions such as NOx, PM, and SOx, which are exacerbated by stringent regulations like EPA Tier 4 locomotive emissions, and current aftertreatment systems increase manufacturing costs and fuel consumption.
Innovation Solution
A system and method that utilizes a turbocharger with exhaust gas recirculation, adjusting fuel injection timing and pressure, and reducing engine speed to control NOx and PM emissions, eliminating the need for aftertreatment systems by optimizing engine operation through sensors and a control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If aftertreatment systems are used to control exhaust emissions, then emission control effectiveness is improved, but manufacturing cost and fuel consumption increase
Solution Approach 1:
The patent extracts the emission control function from separate aftertreatment systems and integrates it into the engine's core combustion and exhaust management system. By using exhaust gas recirculation through a turbocharger and optimizing fuel injection timing, the invention achieves emission control through the engine's inherent systems rather than adding separate aftertreatment components.
Solution Approach 2:
The turbocharger system is designed to perform multiple functions: it provides exhaust gas recirculation for emission control, maintains engine power output, and optimizes combustion efficiency. The fuel injection system similarly performs multiple functions including combustion control and emission reduction through timing optimization, eliminating the need for dedicated single-function aftertreatment devices.
2Object-generated harmful factors
If engine speed is reduced to lower emissions, then NOx and PM emissions are reduced, but engine power output decreases
Solution Approach 1:
The patent changes multiple operating parameters simultaneously: it reduces engine speed to lower emissions while compensating for power loss by increasing fuel injection quantity, optimizing injection timing to advance combustion, and adjusting exhaust gas recirculation rates. This multi-parameter optimization maintains power output despite speed reduction.
Solution Approach 2:
The invention advances the fuel injection timing so that combustion occurs earlier in the cycle, compensating for the reduced engine speed. This preliminary action ensures that peak pressure and torque are generated at the appropriate point in the combustion cycle, maintaining power output while allowing lower operating speeds for emission reduction.
3Object-generated harmful factors
If fuel injection timing is advanced to reduce emissions, then combustion efficiency is improved, but knocking and mechanical stress increase
Solution Approach 1:
The patent dynamically adjusts fuel injection timing based on operating conditions rather than using a fixed advance angle. The control system optimizes injection timing in real-time, advancing it enough to reduce emissions but retarding it when mechanical stress or knocking becomes excessive. This dynamic adjustment allows the system to operate near the optimal point without exceeding mechanical limits.
Solution Approach 2:
The invention uses a control system that monitors engine operation and provides feedback to adjust injection timing. By sensing combustion characteristics and mechanical response, the system can advance timing to reduce emissions when conditions permit, but automatically retard timing when knocking or excessive mechanical stress is detected, maintaining a safe operating envelope.
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 PM emissions while maintaining constant engine power, meeting regulatory requirements without the use of aftertreatment systems, thereby lowering life cycle costs and improving engine efficiency.
Implementation Method 1
directing a first portion of exhaust gases from an exhaust manifold into a first-stage turbine and a second-stage turbine of a turbocharger for expanding the first portion of the exhaust gases
Implementation Method 2
the compressor is configured to receive the fresh air and discharge a compressed air stream
Implementation Method 3
The direct fuel injection atomizes the fuel into droplets, which evaporate and mix with the compressed air in the combustion chambers
Implementation Method 4
combusting a mixture of a flow of fresh air and a fuel within a plurality of cylinders
Data Source
AI summary
A method of operating an internal combustion engine is provided. The method includes combusting a mixture of fresh air and fuel within multiple cylinders. The method also includes directing a first portion of exhaust gases into a first-stage turbine and a second-stage turbine of a turbocharger for expanding the exhaust gases, directing a second portion of exhaust gases from the exhaust manifold via an exhaust channel bypassing the first-stage turbine and recirculating a third portion of exhaust gases into an intake manifold after mixing with fresh air. The method includes controlling at least one of: reducing a normal engine speed at each engine power setting while maintaining constant engine power level by increasing a fuel injection per cycle; concurrently increasing a flow rate of the third portion of exhaust gas during recirculation; and advancing a fuel injection timing for reducing emission levels that meets Tier 4 requirements.