Engine Control Device Combustion Noise Management
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Solution Overview
Problem
Partial compression-ignition combustion engines face challenges in controlling combustion noise while maintaining thermal efficiency, as the timing of self-ignition can vary due to external factors, leading to potential loud noise and reduced marketability.
Innovation Solution
A control device and method for a compression-ignition engine that adjusts the EGR ratio based on detected noise parameters to maintain a noise index below a threshold, switching between combustion modes to balance thermal efficiency and noise reduction, using a combination of spark ignition and compression ignition, and adjusting valve timings and fuel injection strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If partial compression-ignition combustion is executed to improve thermal efficiency, then thermal efficiency is improved, but combustion noise increases due to variable self-ignition timing
Solution Approach 1:
The control device detects combustion noise levels and feeds this information back to adjust the EGR ratio in real-time. When combustion noise exceeds a threshold, the system increases EGR to suppress noise, creating a closed-loop control system that dynamically balances thermal efficiency and noise reduction.
Solution Approach 2:
The system changes the EGR ratio parameter dynamically based on detected combustion noise levels. By adjusting this physical parameter, the system modifies the combustion characteristics to reduce noise while preserving thermal efficiency benefits of partial compression-ignition combustion.
2Object-generated harmful factors
If the EGR ratio is increased to reduce combustion noise, then combustion noise is reduced, but thermal efficiency decreases
Solution Approach 1:
The EGR ratio is made dynamic rather than fixed, allowing the system to adjust between noise reduction and thermal efficiency based on real-time combustion conditions. The control device increases EGR only when noise exceeds thresholds, maintaining optimal balance under varying operating conditions.
Solution Approach 2:
The system applies EGR enhancement partially - only when and where combustion noise becomes excessive. Rather than continuously maximizing EGR for noise reduction, the system applies the minimum necessary EGR increase to suppress noise, preserving thermal efficiency during normal operation.
3Measurement precision
If spark ignition timing is advanced to control CI combustion timing, then combustion timing control is improved, but combustion noise increases
Solution Approach 1:
The control device uses spark ignition as an intermediary mechanism to indirectly control CI combustion timing. Rather than directly controlling self-ignition, the system uses spark-induced flame propagation to prepare the combustion environment, allowing timing control without the noise penalty of direct spark timing adjustment.
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 effectively reduces combustion noise while preserving thermal efficiency by adjusting the EGR ratio and switching between combustion modes, ensuring a stable and quiet operation even under varying engine conditions.
Implementation Method 1
an EGR controller to change an EGR ratio that is a ratio of exhaust gas recirculated into the cylinder
Implementation Method 2
a portion of a mixture gas inside a cylinder is combusted by spark-ignition
Implementation Method 3
the remaining mixture gas inside the cylinder is combusted by self-ignition (CI (Compression Ignition) combustion)
Data Source
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AI summary
A control device for a compression-ignition engine is provided, in which partial compression-ignition combustion including spark ignition combustion performed by combusting a portion of mixture gas inside a cylinder by spark-ignition followed by compression ignition combustion performed by causing the rest of the mixture gas inside the cylinder to self-ignite is executed within a part of an operating range of the engine. The device includes a detector configured to detect a parameter related to noise caused by the combustion inside the cylinder, a manipulator configured to change an EGR ratio being a ratio of exhaust gas introduced into the cylinder, and a controller configured to control the manipulator to increase the EGR ratio based on the detected parameter of the detector.