Engine Controller Combustion Mode Switching for Noise Masking
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Solution Overview
Problem
Premixed combustion in engines generates loud noise due to its shorter combustion time, making it difficult to maintain vehicle quietness while improving emission performance and riding comfort.
Innovation Solution
An engine controller that switches between premixed and diffusion combustion operations based on the vehicle's gear position, adjusting fuel and oxygen distribution and engine speed/load conditions to minimize noise, using a detector to assess gear position and a changer to modify operational conditions, including increasing engine speed and load limits and setting a predetermined time for switching between combustion modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If premixed combustion operation is performed to improve emission performance, then NOx and soot emissions are reduced, but combustion noise increases due to shorter combustion time
Solution Approach 1:
The patent dynamically switches between premixed combustion and diffusion combustion modes based on vehicle traveling state and gear position. The combustion mode is not fixed but adapts to changing operating conditions, allowing the system to optimize between emission performance and noise levels in real-time.
Solution Approach 2:
The patent changes key combustion parameters including intake-air oxygen level (controlled to be lower in premixed mode), engine speed limits (increased in lower gears), and load limits (increased in lower gears) depending on the combustion mode and gear position. These parameter adjustments enable the system to resolve the contradiction between emissions and noise.
2Object-generated harmful factors
If premixed combustion is used to reduce emissions, then emission performance improves, but vehicle quietness deteriorates
Solution Approach 1:
The system dynamically adjusts combustion mode based on gear position detected by the detector. In higher gears where vehicle noise masks combustion noise, premixed combustion is favored for emission benefits. In lower gears where quietness is more critical, diffusion combustion is selected to maintain vehicle quietness.
Solution Approach 2:
The gear position acts as an intermediary parameter that mediates between emission performance and vehicle quietness. The changer uses gear position information to determine the appropriate combustion mode, effectively using the transmission state as a bridge to resolve the contradiction between these two opposing requirements.
3Object-affected harmful factors
If diffusion combustion is used to maintain vehicle quietness, then riding comfort improves, but emission performance deteriorates due to higher combustion temperature
Solution Approach 1:
The patent controls intake-air oxygen level to be lower in premixed combustion mode, which helps reduce combustion temperature and associated emissions when diffusion combustion is not selected. This parameter control enables the system to achieve emission reductions without requiring constant use of diffusion combustion, thus maintaining both quietness and emission performance.
4Productivity
If engine speed and load limits are increased for lower gear positions, then productivity improves, but combustion control complexity increases
Solution Approach 1:
The patent implements dynamic adjustment of engine speed and load limits based on gear position. The detector monitors gear position, and the changer automatically adjusts operational parameters accordingly. This dynamic approach allows the system to expand the usable engine speed and load range in lower gears without requiring complex manual intervention or oversimplified fixed limits.
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 engine controller effectively determines traveling states where premixed combustion noise is masked, enhancing emission performance and riding comfort by optimizing combustion operations based on gear position, thereby improving vehicle quietness and emission performance.
Implementation Method 1
The premixed combustion operation is an operating state of substantially uniformly distributing fuel and oxygen in the cylinders of the engine and burning the resultant mixture by self-ignition
Implementation Method 2
The diffusion combustion operation is an operating state of generating a somewhat inhomogeneous mixture of the fuel and the oxygen and burning the mixture by self-ignition
Data Source
Figure 1
Figure 2A~2D
Figure 3~4
AI summary
A controller (1) of an engine performing a premixed combustion operation and a diffusion combustion operation that are switchable in accordance with the traveling state of a vehicle, includes a detector (2) detecting the gear position of the transmission mounted in the vehicle, and a changer (4) changing the traveling conditions for performing the premixed combustion operation on the basis of the gear position detected by the detector (2).