Engine Injection Timing Control for NOx-Fuel Economy Trade-off
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Solution Overview
Problem
Locomotive engine control systems face challenges in optimizing fuel economy and reducing NOx emissions simultaneously, as optimizations for fuel economy often lead to increased NOx levels, and vice versa, while stringent regulations require maintaining NOx emissions within thresholds.
Innovation Solution
The system dynamically adjusts engine injection timing based on real-time ambient NOx levels estimated by sensors, retarding injection timing in high NOx regions to reduce exhaust NOx and advancing it in low NOx regions to improve fuel economy, while allowing higher NOx emissions in low NOx areas to maintain overall emissions compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If engine injection timing is retarded to reduce exhaust NOx levels, then NOx emissions are reduced, but fuel economy deteriorates
Solution Approach 1:
The engine control system dynamically adjusts injection timing based on real-time ambient NOx sensor readings. The system transitions from static, fixed injection timing to dynamic, condition-based timing adjustment, allowing the engine to adapt injection timing to current environmental conditions and achieve optimal balance between NOx reduction and fuel economy
Solution Approach 2:
The system uses ambient NOx sensors to provide real-time feedback on environmental NOx conditions. This feedback loop enables the control system to continuously monitor ambient NOx levels and adjust injection timing accordingly, creating a closed-loop control system that responds to changing environmental conditions
2Use of energy by moving object
If engine operations are optimized for fuel economy, then fuel efficiency is improved, but exhaust NOx levels increase
Solution Approach 1:
The system enables dynamic optimization of fuel economy by adjusting injection timing based on ambient conditions. When ambient NOx levels are low, the system can afford to use more fuel-efficient timing strategies, and when ambient levels are high, it adjusts timing to reduce NOx, creating a dynamic fuel economy optimization strategy
Solution Approach 2:
The system changes the injection timing parameter based on ambient NOx sensor readings. By varying this critical combustion parameter in response to environmental conditions, the system achieves adaptive optimization of both fuel economy and emissions performance
3Object-generated harmful factors
If injection timing is retarded by higher amount in high NOx regions, then emissions compliance is achieved, but fuel economy and CO2 performance deteriorate
Solution Approach 1:
The system applies different injection timing strategies to different geographic regions based on local ambient NOx conditions. In high NOx regions, more aggressive timing retardation is applied, while in low NOx regions, milder adjustments are used, creating location-specific optimization that balances compliance with fuel economy
Solution Approach 2:
The system applies partial timing adjustment rather than full retardation in all conditions. By modulating the degree of timing retardation based on the severity of ambient NOx conditions, the system achieves emissions compliance with minimal impact on fuel economy, avoiding excessive action that would unnecessarily harm performance
Data Source
AI summary
Methods and systems are provided for improving a balance between engine fuel economy and exhaust emissions in an off-highway vehicle. One example method includes adjusting an engine injection timing based on an ambient NOx level estimated by a NOx sensor in the engine intake. Another example method includes adjusting a trip plan with a time in notch duty cycle based on a deviation from the time in notch duty cycle from a reference duty cycle.