Diesel Engine DPF Regeneration Control Strategy
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Solution Overview
Problem
Existing diesel particulate filter (DPF) regeneration methods are inefficient due to reliance on differential pressure estimates, which do not accurately account for ash accumulation, leading to improper regeneration timing and increased lubricating oil dilution and fuel consumption.
Innovation Solution
A diesel engine system with an oxidation catalyst, diesel particulate filter, differential pressure detection, and control means for regeneration, including first, second, and third regeneration modes, where first regeneration occurs without additional injection at active catalyst temperature, second regeneration uses injection to burn non-oxidizable particulate matter, and third regeneration occurs in a non-working state with injection, with temperature and time-based controls to optimize regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If regeneration is performed only when PM accumulation exceeds threshold based on differential pressure, then the system is simple to operate, but regeneration efficiency is poor and lubricating oil dilution increases
Solution Approach 1:
The system performs preliminary estimation of ash accumulation based on operating time and fuel consumption before deciding on regeneration timing. This allows the system to proactively schedule regeneration operations based on predicted ash levels rather than waiting for differential pressure to indicate severe accumulation, thereby improving regeneration efficiency while maintaining operational simplicity
Solution Approach 2:
The system incorporates feedback mechanisms by continuously monitoring differential pressure, estimating ash accumulation based on operating parameters, and adjusting regeneration timing accordingly. This closed-loop approach ensures regeneration is performed at optimal moments to maximize efficiency while preventing lubricating oil dilution
2Reliability
If additional injection is used frequently for regeneration, then particulate matter is completely removed, but lubricating oil dilution and fuel consumption increase
Solution Approach 1:
The system applies partial action by using additional injection only when necessary - specifically when ash accumulation estimation indicates it will improve regeneration effectiveness. For cases where passive regeneration or oxidation catalyst alone is sufficient, additional injection is omitted, thereby reducing lubricating oil dilution and fuel consumption while maintaining adequate PM removal
Solution Approach 2:
The system changes the parameter of regeneration timing by estimating ash accumulation based on operating time and fuel consumption. This allows optimization of when additional injection is applied, ensuring it is used only when beneficial for complete PM removal while minimizing unnecessary use that would cause lubricating oil dilution and increased fuel consumption
3Difficulty of detecting and measuring
If regeneration timing is based solely on differential pressure, then measurement is simple, but accuracy of PM accumulation estimation is poor due to ash divergence
Solution Approach 1:
The system introduces an intermediary estimation method that uses operating time and fuel consumption as intermediate parameters to estimate ash accumulation. This intermediary approach bridges the gap between simple differential pressure measurement and accurate total PM accumulation assessment, allowing the system to account for ash that differential pressure alone cannot detect
Solution Approach 2:
The system employs a multi-functional assessment approach that combines differential pressure measurement with operating time-based ash estimation. This universal method serves multiple functions: it maintains the simplicity of differential pressure sensing while adding the capability to estimate total PM accumulation including ash, thereby improving measurement precision without significantly increasing system complexity
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 allows for efficient DPF regeneration based on operation conditions, reducing lubricating oil dilution, fuel consumption, and preventing runaway combustion, while minimizing errors in particulate matter estimation and oxidation catalyst thermal stress.
Implementation Method 1
PM is oxidatively removed by means of an additional injection or the like only when the amount of accumulated PM estimated from the differential pressure between before and after the DPF exceeds the prescribed threshold value
Implementation Method 2
a diesel particulate filter; PM is collected when exhaust gas passes through the DPF
Implementation Method 3
second regeneration which uses the additional injection, wherein particulate matter other than ash which cannot be oxidatively removed is completely burned and removed
Data Source
AI summary
Provided is a diesel engine which can efficiently regenerate a diesel particulate filter. The control for regeneration using an ECU includes a first regeneration by burning particulate matter at slightly more than 300° C. for 20 minutes when the accumulation of particulate matter exceeds a first threshold; a second regeneration by burning particulate matter at approximately 560° C. for 30 minutes by an additional injection to remove particulate matter other than ash when the accumulation of particulate matter exceeds the first threshold for a first predetermined period of time, or every 100 hours; and a third regeneration by burning particulate matter at approximately 600° C. for 15 minutes by an additional injection to remove particulate matter other than ash when the accumulation of particulate matter exceeds a second threshold and an emergency regeneration switch is pushed, or after 50 hours since the second or third regeneration and the emergency regeneration switch is pushed.