Engine Fueling Control for Cylinder Deactivation Puddle Dynamics
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Solution Overview
Problem
Existing engine systems face challenges in maintaining accurate air-fuel ratio control during transient operations due to fuel puddling in the intake manifold, particularly when cylinders are selectively deactivated, leading to fluctuations and inefficiencies.
Innovation Solution
An engine controller adjusts fuel injection based on the induction state of cylinders, using calibrated gains and time constants to track fuel puddle mass and vapor content, clipping values when vapor pressure reaches saturation limits, and applying different models for active and deactivated cylinders to improve fuel dynamics and reduce air-fuel ratio perturbations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cylinders are selectively deactivated to improve fuel economy, then fuel efficiency increases, but fuel puddle dynamics become more complex and air-fuel ratio control deteriorates
Solution Approach 1:
The patent segments the fuel management system by cylinder induction state, maintaining separate fuel puddle mass estimates and evaporation rate calculations for active and deactivated cylinders. This segmentation allows tailored compensation strategies for each cylinder type, resolving the contradiction by enabling precise control (improving reliability) while maintaining the deactivation strategy (preserving fuel economy).
Solution Approach 2:
The system performs preliminary compensation for fuel puddle effects before combustion occurs in each cylinder. By calculating and compensating for fuel puddle mass and evaporation rates in advance based on cylinder induction state, the system ensures accurate air-fuel ratio control is established before the combustion event, maintaining reliability during deactivation operations.
2Measurement precision
If fuel injection is increased to compensate for wall wetting, then air-fuel ratio accuracy improves, but fuel delivery complexity increases
Solution Approach 1:
The patent applies local quality by differentiating fuel compensation parameters based on individual cylinder induction states. Each cylinder receives tailored fuel puddle compensation based on its specific state (active or deactivated), allowing precise air-fuel ratio control for each cylinder while managing overall system complexity through modular, cylinder-specific calculations.
3Stability of the object's composition
If fuel puddle compensation is applied during transient operations, then air-fuel ratio stability improves, but control system complexity increases
Solution Approach 1:
The system dynamically adjusts fuel compensation based on real-time cylinder induction states and operating conditions. By continuously updating fuel puddle mass estimates and evaporation rate calculations as cylinders transition between active and deactivated states, the control system maintains air-fuel ratio stability during transient operations while adapting to changing conditions.
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
This approach enhances fuel economy and reduces air-fuel ratio errors by accurately accounting for fuel puddle dynamics in both active and deactivated cylinders, ensuring more precise fueling and improved engine efficiency.
Implementation Method 1
The injected fuel quickly vaporizes due to the heat from the valve and mixes with the intake air
Implementation Method 2
the amount of fuel added to the film each cycle by the fuel injection is equal to the fuel removed by vaporization and liquid film flow
Data Source
AI summary
Methods and systems are provided for tracking a fuel puddle mass in the intake port of a deactivated engine cylinder. The difference in fuel evaporation rate in the deactivated cylinder intake is accounted for by applying distinct time constant and gain values to a transient fuel compensation model. A fuel vapor content is clipped once the intake vapor pressure in the intake port of the deactivated cylinder reaches a saturation pressure limit.