Engine Idle Speed Control for Hydrocarbon Emission Management
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Solution Overview
Problem
Internal combustion engines face challenges in controlling hydrocarbon and NOx emissions during idle operation without adversely affecting fuel economy or operator performance, as existing methods require sensor input and struggle to maintain predetermined emission levels within mandated time frames.
Innovation Solution
An electronically controlled method that determines engine idle status and duration, increasing engine speed to burn off hydrocarbons when idle exceeds a predetermined time, using stored values to manage hydrocarbon content without sensor input, and potentially overriding extended idle modes to enhance exhaust temperature for regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the engine increases speed to reduce hydrocarbon emissions during idle, then hydrocarbon content decreases, but fuel economy deteriorates
Solution Approach 1:
The engine control system implements periodic speed increases during idle operation to burn off accumulated hydrocarbons. The ECU monitors idle duration and triggers speed increases at predetermined intervals, allowing the engine to alternately operate at idle speed and elevated speeds, thereby periodically reducing hydrocarbon buildup without maintaining continuously high fuel consumption
Solution Approach 2:
The system performs preliminary detection of idle duration and hydrocarbon accumulation levels before triggering speed increases. The ECU uses stored time values and predetermined thresholds to anticipate when hydrocarbon buildup will occur, enabling proactive emission control rather than reactive response, thus preventing excessive hydrocarbon accumulation while minimizing unnecessary fuel consumption
2Ease of operation
If the engine operates in extended idle mode to maintain cabin environment, then operator comfort improves, but hydrocarbon and NOx emissions increase
Solution Approach 1:
The engine control system dynamically adjusts idle speed based on operating duration and emission accumulation. Rather than maintaining a fixed idle speed, the ECU modifies speed parameters in real-time, increasing speed when hydrocarbon thresholds are approached and returning to lower idle speeds when emissions are reduced, thereby adapting to changing emission conditions while maintaining cabin environment
Solution Approach 2:
The system changes engine operating parameters including speed, duration, and temperature based on predetermined criteria. The ECU monitors idle time against stored values and adjusts speed parameters to prevent emission thresholds from being exceeded, using parameter modulation to balance emission control with the need for extended idle operation during parked conditions
3Use of energy by moving object
If the engine ramps back to idle quickly after speed increase, then fuel economy improves, but emission control precision deteriorates
Solution Approach 1:
The engine control system implements feedback mechanisms where the ECU continuously monitors emission levels and idle duration, using this information to determine when and how to ramp back to idle speed. The predetermined levels and time-based criteria provide feedback thresholds that guide the transition timing, ensuring emission control precision is maintained while optimizing fuel economy through timely return to idle operation
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
Effectively limits hydrocarbon and NOx emissions in exhaust streams during engine idle without sensor input, maintaining performance and fuel economy by using predetermined engine speed and time-based strategies for hydrocarbon management and regeneration.
Implementation Method 1
increase engine speed to increase exhaust temperature and initiate HC burnoff
Data Source
AI summary
A method and computer readable medium are disclosed to control operation of an internal combustion engine having an electronic control unit (ECU) with memory to burn off HC in an engine exhaust system and limit hydrocarbon and NOx content in the engine exhaust stream while operating the engine in idle mode.