Compression Ignition Engine Control Device for Combustion Noise Reduction
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Solution Overview
Problem
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, leading to increased noise levels.
Innovation Solution
A control device that adjusts the injection timing and amount of pre-injection fuel based on oxygen concentration, using an intake O2 sensor to maintain an optimal interval between pressure peaks to cancel out combustion noise, and performs divided injections to ensure effective homogenization of the mixture gas.
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 significantly 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 adjusting its timing and amount, while the main injection is optimized for torque production. This segmentation allows independent optimization of noise control and power output without mutual interference.
Solution Approach 2:
The pre-injection is performed before the main injection to prepare the combustion chamber conditions. By adjusting the pre-injection timing and amount based on combustion environmental factors, the system proactively controls the ignition delay and pressure peak characteristics, preventing excessive combustion noise before it occurs while maintaining optimal main injection timing for torque.
2Manufacturing precision
If the injection timing of the pre-injection is adjusted to correct for ignition delay variations, then the pressure peak timing can be maintained, but the combustion noise cancellation effect is degraded
Solution Approach 1:
The system uses feedback from oxygen concentration sensors and combustion state detection to dynamically adjust the pre-injection timing and amount. This feedback mechanism allows the system to maintain the optimal interval between pressure peaks for noise cancellation while compensating for variations in ignition delay caused by changing combustion environmental factors.
Solution Approach 2:
The system dynamically changes the injection timing and amount parameters of the pre-injection based on detected combustion conditions. By adjusting these parameters in response to oxygen concentration and other environmental factors, the system maintains both accurate pressure peak timing and effective noise cancellation across varying operating conditions.
3Productivity
If the oxygen concentration increases, then the combustion efficiency improves, but the first peak timing deviates and combustion noise increases
Solution Approach 1:
The system dynamically adjusts the pre-injection timing and amount in response to changing oxygen concentration. When oxygen concentration increases, the system modifies these parameters to compensate for the resulting ignition delay changes, maintaining both high combustion efficiency and effective noise cancellation across varying air 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 solution effectively reduces combustion noise by maintaining peak intervals that cancel out pressure waves, improving engine performance and market value by stabilizing noise levels regardless of oxygen concentration changes.
Implementation Method 1
an intake O2 sensor configured to acquire an oxygen concentration of intake air supplied to the combustion chamber
Implementation Method 2
causes fuel injected into a combustion chamber from an injector to combust by compression ignition
Implementation Method 3
causes fuel injected into a combustion chamber from an injector to combust by compression ignition
Implementation Method 4
causes fuel injected into a combustion chamber from an injector to combust by compression ignition
Implementation Method 5
the pressure wave of combustion by the pre-injection and the pressure wave of combustion by the main injection cancel each other out
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 an oxygen concentration of intake air supplied to 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 concentration increase is not detected under a condition that engine load and speed are the same.