SISO Engine Feedback Control for Emissions Variation
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Solution Overview
Problem
Internal combustion engines exhibit variations in emissions due to engine-to-engine biases, random noise, and sensor noise, leading to differences in emissions output even when operating under the same conditions, which complicates compliance with emissions requirements.
Innovation Solution
A single-input-single-output (SISO) control system that adjusts operating parameters like exhaust gas recirculation (EGR) and charge air mass flow (MCF) based on differences between pre-calibrated reference values and measured emissions characteristics, using a controller to minimize these variations and ensure compliance with emissions standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-calibrated reference values are used for engine control, then emissions compliance can be achieved under ideal conditions, but engine-to-engine variations and sensor noise cause deviations from target emissions
Solution Approach 1:
The patent implements a feedback control system that continuously monitors emissions characteristics (NOx, O2, lambda) and adjusts engine operating parameters based on the difference between measured values and target values. The controller receives feedback signals from emissions sensors and modifies actuators (EGR valve, fuel injectors) to minimize deviations from emissions targets, thereby maintaining compliance despite engine variations and sensor noise.
Solution Approach 2:
The system dynamically adjusts multiple engine operating parameters including exhaust gas recirculation (EGR) fraction, charge air mass flow (MCF), fueling rates, and injection timing based on feedback from emissions measurements. By changing these parameters in response to measured emissions characteristics, the system adapts to engine-to-engine variations and maintains emissions within compliance limits.
2Reliability
If multiple engine operating parameters are controlled simultaneously, then emissions performance can be optimized, but control system complexity increases
Solution Approach 1:
The control system is segmented into separate control loops for different emissions characteristics (NOx control, O2 control, lambda control). Each loop independently adjusts specific operating parameters to control particular emissions outputs. This segmentation allows complex multi-parameter control to be broken down into manageable subsystems, reducing overall system complexity while maintaining comprehensive emissions optimization.
Solution Approach 2:
The engine control module (ECM) serves multiple functions: it controls EGR fraction, adjusts charge air mass flow, manages fueling rates, and optimizes injection timing. A single controller handles all these parameters and emissions monitoring tasks, reducing the need for separate dedicated control systems for each function and thereby simplifying the overall architecture.
3Stability of the object's composition
If engine operating parameters are adjusted to compensate for sensor noise, then emissions consistency can be improved, but control responsiveness may be reduced
Solution Approach 1:
The system uses pre-calibrated reference values and target emissions characteristics that are determined beforehand through extensive modeling and testing. These pre-established targets serve as benchmarks that guide real-time control adjustments, allowing the system to respond appropriately to sensor readings without overreacting to noise. The preliminary characterization of engine behavior enables smoother, more stable control actions.
Solution Approach 2:
The control system dynamically adjusts the weighting and response characteristics of control loops based on operating conditions. During transient operations, the system may prioritize responsiveness to maintain stability, while during steady-state operation, it emphasizes emissions consistency. The controller adapts its control strategy in real-time based on the current operating point, balancing responsiveness and stability as needed.
Data Source
AI summary
This disclosure provides a system and method for controlling internal combustion engine system to reduce operation variations among plural engines. The system and method utilizes single-input-single-output (SISO) control in which a single operating parameter lever is selected from among exhaust gas recirculation (EGR) fraction and charge air mass flow (MCF), and a stored reference value associated with the selected lever is adjusted for an operating point in accordance with a difference between a measured emissions characteristic and a pre-calibrated reference value of the emissions characteristic for that operating point. Adjusting the selected operating parameter lever towards the theoretical pre-calibrated reference value of the operating parameter lever for each of plural operating points can reduce engine-to-engine variations in engine out emissions.