Air Handling Control for Opposed-Piston Uniflow Engines
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Solution Overview
Problem
Two-stroke cycle opposed-piston engines with uniflow scavenging face challenges in maintaining consistent trapped charge composition and emissions performance due to variations in engine operating conditions, leading to inconsistent combustion and emissions.
Innovation Solution
Active control of intake manifold pressure, exhaust gas recirculation flow, and fresh air flow through the use of advanced control mechanisms and sensors, including EGR valves, supercharger adjustments, and backpressure control, to maintain optimal trapped conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active control mechanisms (EGR valves, supercharger adjustments, backpressure control) are implemented to maintain optimal trapped conditions, then combustion consistency and emissions performance are improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic control of the air handling system by making EGR valve positions, supercharger speeds, and backpressure valve settings adjustable in real-time based on operating conditions. This allows the system to adapt and maintain optimal trapped charge composition across varying engine loads and speeds, resolving the contradiction between reliability and complexity through controlled adaptability.
Solution Approach 2:
The control system uses feedback from sensors monitoring trapped charge composition, combustion parameters, and emissions to continuously adjust EGR valve positions, supercharger speed, and backpressure settings. This closed-loop control ensures consistent combustion performance while managing the complexity through intelligent regulation rather than fixed mechanical designs.
2Object-generated harmful factors
If multiple control mechanisms (EGR valves, supercharger adjustments, backpressure control) are used to reduce emissions variability, then emissions performance is improved, but ease of operation deteriorates
Solution Approach 1:
The air handling control system is designed to autonomously regulate EGR flow, charge air pressure, and backpressure without requiring manual intervention. The control mechanisms self-adjust based on pre-programmed logic and sensor feedback, maintaining optimal emissions performance while eliminating the operational burden that would arise from manual control of multiple parameters.
3Productivity
If air handling system setpoints are continuously adjusted in response to changing engine conditions, then combustion optimality is improved, but loss of time for control adjustments increases
Solution Approach 1:
The control system pre-establishes optimal setpoints for EGR valves, supercharger speed, and backpressure valves based on anticipated operating conditions and engine speed. By preparing control adjustments in advance and using feedforward control strategies, the system minimizes response time while maintaining optimal combustion efficiency across transitioning operating states.
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
Ensures repeatable and optimal combustion and emissions performance by adjusting air handling system setpoints in response to changing engine conditions, improving engine efficiency and reducing emissions variability.
Implementation Method 1
A turbocharger includes a turbine that rotates on a shaft and that is coupled to the exhaust subsystem, and a compressor that rotates on the shaft with the turbine and that is coupled to the charge air subsystem
Implementation Method 2
A charge air cooler in the charge air channel is coupled to receive and cool the charge air before delivery to the intake port of the engine
Data Source
AI summary
In an air handling system of a uniflow-scavenged, two-stroke cycle opposed-piston engine, repeatable trapped mass and composition are achieved by determining provision of air handling setpoints that control operation of the engine's air handling system components. In some aspects, these setpoints govern operations of the air handling system by actively controlling the intake manifold pressure (IMP), EGR flow, and exhaust channel backpressure.