Compression Ignition Engine Control Device Combustion Noise Reduction
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Solution Overview
Problem
Existing compression ignition engines face challenges in reducing combustion noise due to variations in ignition delay caused by environmental factors, which affect the timing and height of pressure peaks from pre-injection and main injection, leading to increased noise levels.
Innovation Solution
The solution involves adjusting the injection amount and timing of the pre-injection to maintain the interval between pressure peaks from pre-injection and main injection, ensuring they cancel each other out, by estimating and correcting for deviations in wall surface temperature, thereby reducing combustion noise effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the injection timing of the main injection is corrected according to the change in combustion environmental factors, then the combustion noise can be reduced, but the thermal efficiency and torque are greatly influenced
Solution Approach 1:
The fuel injection is divided into two separate injections: pre-injection and main injection. The pre-injection is used to control combustion noise by creating a pressure wave that cancels out the combustion noise from the main injection, while the main injection is optimized for power generation. This segmentation allows independent optimization of noise control and power output without compromising either.
Solution Approach 2:
The pre-injection is performed before the main injection to prepare the combustion chamber with a controlled amount of fuel that will combust first. This preliminary combustion creates a pressure wave at a specific timing that cancels out the combustion noise from the subsequent main injection, allowing noise control to be achieved in advance without affecting the main power-generating combustion.
2Object-affected harmful factors
If the injection timing of the main injection is changed to compensate for ignition delay variation, then the combustion noise can be reduced, but the engine performance deteriorates due to the great influence on thermal efficiency
Solution Approach 1:
The fuel injection is divided into two separate injections: pre-injection and main injection. The pre-injection is used to control combustion noise by creating a pressure wave that cancels out the combustion noise from the main injection, while the main injection is optimized for power generation. This segmentation allows independent optimization of noise control and power output without compromising either.
Solution Approach 2:
The pre-injection acts as an intermediary mechanism between the combustion chamber and the main injection. It creates a controlled combustion event that generates a pressure wave to counteract the harmful combustion noise from the main injection, serving as a mediator that protects the main power-generating combustion from causing excessive noise.
3Object-affected harmful factors
If the interval between pre-injection and main injection peaks is deviated from the expected interval due to ignition delay variation, then the pressure waves cannot cancel each other out, but correcting main injection timing affects engine performance
Solution Approach 1:
The fuel injection is divided into two separate injections: pre-injection and main injection. The pre-injection is used to control combustion noise by creating a pressure wave that cancels out the combustion noise from the main injection, while the main injection is optimized for power generation. This segmentation allows independent optimization of noise control and power output without compromising either.
Solution Approach 2:
The timing and amount of pre-injection are adjusted based on detected wall surface temperature to compensate for ignition delay variations. By changing the pre-injection parameters rather than the main injection parameters, the system maintains optimal noise cancellation while preserving stable engine operation and performance.
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 effectively reduces combustion noise by maintaining the optimal interval between pressure peaks, improving engine performance and market value by minimizing noise levels regardless of temperature changes.
Implementation Method 1
the pressure wave of combustion by the pre-injection and the pressure wave of combustion by the main injection cancel each other out
Implementation Method 2
fuel injected into a combustion chamber from an injector to combust by compression ignition
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A control device for a compression ignition engine is provided, which causes an injector to perform a pre-injection and a main injection, sets fuel injection timings of these injections so that an interval between a first peak of a heat release rate resulting from the combustion of fuel injected by the pre-injection and a second peak of the heat release rate resulting from the combustion of fuel injected by the main injection becomes an interval to make pressure waves caused by these combustions cancel each other out, and when an increase of a wall surface temperature of a combustion chamber is detected, controls the injector to reduce the injection amount and retard the injection timing of the pre-injection compared with a case where the temperature increase is not detected, under a condition that engine load and speed are the same.