Marine Engine Control Module for Lean-Burn Mode Transitions
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Solution Overview
Problem
Current marine internal combustion engine control systems face challenges in efficiently transitioning between stoichiometric and lean-burn operations, particularly in managing fuel/air equivalence ratios to optimize fuel economy and emissions while maintaining engine performance and stability.
Innovation Solution
The implementation of a control module that uses separate sets of mapped parameter values for stoichiometric and lean-burn operations, with dynamic transition algorithms based on engine speed, throttle position, and operator demand, allowing for seamless adjustments in spark timing, fuel quantity, and air supply to achieve desired fuel/air equivalence ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine operates in lean-burn mode to improve fuel economy, then fuel consumption decreases, but engine stability and responsiveness to operator demand may deteriorate
Solution Approach 1:
The control system dynamically transitions between stoichiometric and lean-burn operating modes based on real-time monitoring of engine conditions and operator demand. The system can switch from a first set of mapped parameter values (stoichiometric) to a second set (lean-burn) and back again, allowing the engine to maintain stability during transient conditions while achieving fuel economy benefits during steady-state operation
Solution Approach 2:
The system changes operating parameters (fuel/air equivalence ratio, spark timing, fuel quantity, air supply) by selecting between different sets of mapped parameter values. The control module adjusts these parameters based on engine speed, throttle position, and operator demand to optimize the balance between fuel economy and engine stability
2Object-generated harmful factors
If the engine transitions between stoichiometric and lean-burn modes to reduce emissions, then emissions decrease, but transition timing and control complexity increase
Solution Approach 1:
The control system continuously monitors engine operating conditions including engine speed, throttle position, and operator demand. This feedback is used to determine when to transition between stoichiometric and lean-burn modes, ensuring emissions are reduced while maintaining proper transition timing based on actual engine state rather than predetermined schedules
Solution Approach 2:
The system uses dynamic transition algorithms that adapt to changing operating conditions. The control module evaluates multiple parameters (engine speed, throttle position, operator demand) to determine optimal transition timing, reducing control complexity compared to rigid predetermined schedules while still achieving emissions reduction goals
3Speed
If the engine responds immediately to operator demand changes, then responsiveness improves, but engine stability during transition may deteriorate
Solution Approach 1:
The control system dynamically evaluates operator demand changes against current engine operating conditions. When transitioning between operating modes, the system considers engine speed and throttle position to determine the appropriate response, allowing rapid adaptation to operator demands while maintaining combustion stability through controlled parameter transitions
Solution Approach 2:
The system adjusts combustion parameters (fuel quantity, air supply, spark timing) based on the selected set of mapped parameter values. By changing these parameters in a coordinated manner during mode transitions, the system maintains combustion stability while still responding effectively to operator demand changes
Data Source
AI summary
A method for controlling a marine internal combustion engine includes operating the engine in a lean-burn mode, wherein a first fuel/air equivalence ratio of an air/fuel mixture in a combustion chamber of the engine is less than 1. The method includes comparing a change in operator demand to a delta demand deadband; comparing a speed of the engine to an engine speed deadband; and comparing a throttle position setpoint to a throttle position threshold. The method also includes immediately disabling the lean-burn mode in response to: (a) the change in operator demand being outside the delta demand deadband, and (b) at least one of: (i) the engine speed being outside the engine speed deadband, and (ii) the throttle position setpoint exceeding the throttle position threshold. The engine thereafter operates according to a set of mapped parameter values configured to achieve a second fuel/air equivalence ratio of at least 1.