Diesel Exhaust Soot Regeneration Control via Dynamic Temperature Feedback
Solution Overview
Problem
Existing diesel engine exhaust gas emission control systems face challenges in preventing excessive temperature rise and oil dilution during diesel particulate filter (DPF) regeneration, as current methods based on DPF temperature control fail to accurately detect soot regeneration amount and rate, leading to potential catalyst degradation and prolonged regeneration times.
Innovation Solution
An exhaust gas emission control system that directly controls the soot regeneration amount by setting a target soot regeneration amount, using a regeneration control device with a late post-injection unit to adjust fuel injection timing and quantity, ensuring optimal temperature and regeneration time management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the target temperature is set high to accelerate soot combustion, then regeneration speed is improved, but the risk of excessive temperature rise increases
Solution Approach 1:
The patent implements feedback control by calculating the soot deposition amount based on differential pressure across the DPF and using this information to adjust the target temperature dynamically. The control unit reduces the target temperature when soot deposition exceeds a predetermined threshold, preventing excessive temperature rise while maintaining efficient regeneration when soot levels are low.
Solution Approach 2:
The target temperature is made dynamic rather than fixed. The control unit adjusts the target temperature based on real-time soot deposition conditions, switching between high target temperatures (for efficient regeneration) and low target temperatures (to prevent overheating when soot is excessive), thereby adapting the system to current operational needs.
2Temperature
If the target temperature is set low to prevent excessive temperature rise, then temperature safety is improved, but regeneration time is increased
Solution Approach 1:
The system uses feedback from soot deposition measurements to intelligently adjust target temperature. When soot deposition is within acceptable limits, the control unit sets a higher target temperature to accelerate regeneration. When soot deposition exceeds thresholds, the target temperature is reduced to prevent overheating, thus optimizing the balance between speed and safety.
Solution Approach 2:
The patent changes the target temperature parameter dynamically based on soot deposition conditions. By adjusting this critical parameter according to real-time feedback, the system achieves fast regeneration when safe and conservative temperature control when necessary, resolving the contradiction between speed and safety.
3Temperature
If long regeneration time is allowed, then temperature control safety is improved, but the risk of oil dilution increases
Solution Approach 1:
The control unit continuously monitors soot deposition and adjusts target temperature accordingly. This feedback mechanism enables the system to complete regeneration efficiently at higher temperatures when soot levels permit, thereby reducing overall regeneration time and minimizing the window during which unburned fuel could dilute engine oil, while still maintaining temperature safety through dynamic adjustment.
Solution Approach 2:
When soot deposition conditions allow, the system rapidly completes regeneration by maintaining higher target temperatures, effectively 'rushing through' the regeneration process. This minimizes the duration of operation where late post-injected fuel might fall into the oil pan, reducing oil dilution risk while completing the necessary thermal treatment.
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 minimizes the risk of excessive temperature rise and oil dilution by maintaining a constant soot regeneration amount, optimizing DPF temperature control, and reducing the risk of catalyst degradation while shortening regeneration time.
Implementation Method 1
oxidation reaction is caused by an oxidation catalyst (hereafter, abbreviated as DOC) arranged upstream of the DPF, so that heat obtained by this reaction is utilized
Implementation Method 2
burn the soot deposited on the DPF
Data Source
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AI summary
An exhaust gas emission control system for a diesel engine, having an oxidation catalyst (DOC) (7) and a diesel particulate filter (DPF) (9) in an exhaust passage, wherein a late post-injection control unit (62), which injects fuel into a combustion chamber at a timing not contributing to combustion in DPF regeneration control, feedback controls a late post-injection amount such that a regeneration amount of soot regenerated by the DPF (9) becomes a target soot regeneration amount.