Diesel Post-Injection Control for Particulate Filter
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Solution Overview
Problem
Existing methods for controlling fuel injection in diesel engines with particulate filters result in unnecessary fuel consumption and high pollution, as well as oil film dilution in combustion chambers, leading to poor lubrication due to the minimum flow rate of injectors during post-injection stages.
Innovation Solution
The method introduces a combination of 'simple' and 'combined' cycles, where post-injection is deferred and added to subsequent cycles, ensuring the total fuel injected corresponds to theoretical amounts, with 'combined' cycles injecting fuel for a total duration equal to the product of cycle number and duration, minimizing each injection's duration to limit fuel dilution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If post-injection is performed with minimum flow rate during each cycle, then the particulate filter receives sufficient fuel to maintain temperature, but unnecessary fuel consumption increases and pollution levels rise
Solution Approach 1:
The patent merges multiple post-injection cycles into a single combined post-injection event. Instead of performing minimum flow rate post-injections during every cycle, the system accumulates the required fuel quantity across multiple cycles and delivers it in one consolidated injection event, thereby reducing total fuel consumption while maintaining filter temperature.
Solution Approach 2:
The system implements periodic post-injection cycles alternating between simple cycles (main injection only) and combined cycles (main injection plus post-injection). This periodic pattern allows the particulate filter to receive fuel periodically rather than continuously, reducing overall fuel consumption while maintaining adequate temperature through accumulated fuel delivery.
2Quantity of substance
If post-injection is performed with minimum flow rate during each cycle, then the particulate filter receives fuel, but oil film dilution in combustion chambers increases leading to poor lubrication
Solution Approach 1:
By combining multiple post-injection events into a single injection with higher flow rate, the patent reduces the number of times fuel contacts the oil film in the combustion chamber. This consolidated approach delivers the same total fuel quantity with fewer exposure events, thereby reducing cumulative oil film dilution and improving lubrication.
Solution Approach 2:
The alternating pattern of simple and combined cycles creates periodic intervals where post-injection occurs only during combined cycles. This periodic action reduces the frequency of fuel-oil film interaction, allowing the oil film to recover between events and minimizing cumulative dilution effects.
3Object-affected harmful factors
If post-injection is deferred and added to subsequent cycles, then fuel dilution is minimized, but the injection timing becomes more complex
Solution Approach 1:
The system performs preliminary accumulation of required post-injection fuel quantity across multiple cycles before executing the combined post-injection. This preliminary action allows the control system to pre-calculate the optimal timing and quantity for the deferred injection, simplifying the control logic despite the deferred timing.
Solution Approach 2:
The injection system dynamically adjusts between simple and combined cycle modes based on accumulated fuel requirements and engine operating conditions. This dynamic switching allows the system to adapt to varying demands while maintaining a relatively simple control structure that only needs to track cumulative injection quantities.
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 ensures only the necessary fuel is injected, reducing pollution and oil film dilution, thereby improving engine lubrication and adhering to theoretical fuel injection maps.
Implementation Method 1
a second determined theoretical quantity of fuel, likely to be injected during a theoretical fuel injection duration, less than the first minimum injection duration, must be injected to supply fuel to the particulate filter in order to cause its temperature to rise
Data Source
Figure 1~2
Figure 3
AI summary
The method involves realizing a simple engine operating cycle comprising a main fuel injection step (PRINC) and not having a post-injection step (POST). A combined engine operating cycle comprising both the main fuel injection step and the post-injection step is realized. Total amount of fuel injected during post-injection step is reduced during determined fuel injection duration (Tinj) based on the theoretical fuel amount determined by a theoretical engine operating cycle associated with a theoretical fuel injection duration (TPOSTH).