Partial Compression-Ignition Engine Control for Combustion Stability
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Solution Overview
Problem
Partial compression-ignition combustion engines face challenges in maintaining combustion stability due to variations in flame core formation and self-ignition timing, leading to unstable engine operation and reduced marketability.
Innovation Solution
A control device and method that adjusts the spark ignition timing and air-fuel ratio to maintain a consistent combustion center of gravity across different engine modes, using an in-cylinder pressure sensor to detect and respond to changes in combustion stability, switching between lean and rich fuel environments to stabilize combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If partial compression-ignition combustion is implemented to improve thermal efficiency, then thermal efficiency is improved, but combustion stability deteriorates due to variations in flame core formation and self-ignition timing
Solution Approach 1:
The control device uses an in-cylinder pressure sensor to detect combustion characteristics in real-time, calculates combustion speed and combustion center of gravity, and feeds this information back to the controller. The controller then adjusts spark ignition timing and fuel injection quantity based on this feedback to maintain stable combustion while achieving high thermal efficiency through partial compression-ignition combustion.
Solution Approach 2:
The system dynamically changes operating parameters including spark ignition timing, fuel injection quantity, and air-fuel ratio based on detected combustion conditions. By adjusting these parameters in response to combustion speed and center of gravity variations, the system maintains combustion stability while operating in the high-efficiency partial compression-ignition mode.
2Reliability
If spark ignition timing is adjusted to maintain combustion center of gravity consistency, then combustion stability is improved, but control complexity increases
Solution Approach 1:
The control system automatically adjusts spark ignition timing and fuel injection quantity based on real-time combustion detection without requiring manual intervention. The ECU self-regulates combustion parameters by calculating combustion speed and center of gravity from pressure sensor data and making appropriate adjustments to maintain stable combustion.
Solution Approach 2:
The system replaces complex mechanical timing adjustment mechanisms with electronic control. The ECU electronically adjusts spark ignition timing and fuel injection based on calculated combustion parameters, substituting mechanical complexity with programmable electronic control that can be updated and adapted through software.
3Use of energy by moving object
If lean air-fuel ratio is used to improve thermal efficiency, then thermal efficiency is improved, but combustion stability deteriorates
Solution Approach 1:
The system dynamically adjusts the air-fuel ratio and fuel injection quantity based on real-time combustion conditions rather than maintaining a fixed lean mixture. The controller modifies fuel injection timing and quantity in response to detected combustion speed and center of gravity, allowing the system to operate with lean mixtures for high efficiency while maintaining stability through active adjustment.
Solution Approach 2:
The control device changes fuel injection quantity and timing parameters based on combustion detection results. When operating with lean air-fuel ratios for high thermal efficiency, the system adjusts these parameters in real-time to prevent combustion instability, achieving both high efficiency and stable 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
The solution ensures stable combustion and improved thermal efficiency by maintaining a consistent combustion center of gravity, reducing engine vibration and perceived mode switching, while optimizing fuel efficiency and thermal performance.
Implementation Method 1
a mixture gas within a cylinder is partially combusted by spark-ignition (SI combustion)
Implementation Method 2
the remaining mixture gas within the cylinder is combusted by self-ignition (CI (Compression Ignition) combustion)
Implementation Method 3
an in-cylinder pressure sensor to detect and respond to changes in combustion stability
Data Source
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AI summary
A control device for a compression-ignition engine in which partial compression-ignition combustion including spark ignition combustion performed by combusting a portion of a mixture gas inside a cylinder by spark-ignition followed by compression ignition combustion performed by causing the remaining mixture gas to self-ignite is executed at least within a part of an engine operating range is provided, which includes a manipulator configured to change an air-fuel ratio, and a controller configured to control the manipulator to reduce the air-fuel ratio, during the partial compression-ignition combustion, based on the combustion stability.