DOC Blockage Risk Detection in Diesel Exhaust Regeneration
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Solution Overview
Problem
Existing diesel engine exhaust gas treatment systems face challenges in preventing blockage of diesel oxidation catalysts (DOC) and maintaining fuel efficiency, as blockages can lead to increased back pressure, fuel inefficiency, and risk of abnormal combustion and oil dilution during forced regeneration of diesel particulate filters (DPF).
Innovation Solution
A regeneration control device that determines the risk of DOC blockage based on engine operation time and temperature, executes a blockage recovery process by increasing the DOC temperature, and synchronizes this with forced regeneration of the DPF, ensuring efficient recovery and regeneration while preventing fuel inefficiency and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If forced regeneration is performed by increasing post injection amount to raise DPF inlet temperature, then the inlet temperature of DPF increases, but the risk of oil dilution increases and fuel efficiency deteriorates
Solution Approach 1:
The system performs preliminary detection of DOC blockage risk before forced regeneration begins. By using a counter to accumulate operation time and comparing it with thresholds, the system identifies blockage risk in advance and adjusts the forced regeneration strategy accordingly, preventing excessive fuel injection and oil dilution
Solution Approach 2:
The system changes the parameter of post injection amount based on the detected DOC blockage risk state. When blockage risk is high, the post injection amount is reduced to prevent oil dilution while still achieving sufficient DPF inlet temperature through alternative means or adjusted regeneration timing
2Temperature
If DOC becomes blocked due to continuous low operation load and low exhaust-gas temperature, then the exhaust pressure increases and fuel efficiency deteriorates, but increasing post injection amount to maintain temperature worsens oil dilution risk
Solution Approach 1:
The system uses feedback from the counter value (accumulated operation time) to continuously monitor DOC blockage risk. This feedback mechanism allows the system to detect when exhaust-gas temperature has been low for extended periods and adjust the post injection amount during subsequent forced regeneration to prevent both DOC blockage and oil dilution
3Productivity
If forced regeneration is executed without considering DOC blockage risk, then the DPF is regenerated, but slipped fuel oxidizes in DPF causing abnormal combustion and heat damage risk
Solution Approach 1:
The system performs preliminary detection of DOC blockage risk using the counter mechanism before initiating forced regeneration. This preliminary action ensures that when forced regeneration is executed, the DOC is functioning properly to oxidize fuel, preventing fuel slip into the DPF and subsequent abnormal combustion
Solution Approach 2:
The counter value provides continuous feedback on DOC blockage risk, allowing the system to make informed decisions about forced regeneration timing and fuel injection amounts, thereby preventing conditions that would lead to DPF heat damage
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
The solution effectively prevents DOC blockage, maintains fuel efficiency, and reduces the risk of damage to the DPF by synchronizing blockage recovery with forced regeneration, thereby improving the overall performance and longevity of the exhaust gas treatment system.
Implementation Method 1
oxidizing the non-combusted fuel with a diesel oxidization catalyst (DOC) so that the temperature of the non-combusted fuel increases
Implementation Method 2
exhaust gas passes through filtering walls which remove PM
Implementation Method 3
The DOC is normally formed of ceramic or the like in a honeycomb-shaped monolith, similarly to the above described DPF, and supports oxidization catalyst on the inner surface of the DOC
Data Source
AI summary
A regeneration control device for an exhaust gas treatment device includes: a DOC blockage risk state determination part configured to determine whether the DOC is in a blockage risk state which is a state where blockage of the DOC is likely to occur, on the basis of comparison between a counter value and a threshold related to an operation time of the diesel engine; a DOC temperature increase execution part configured to execute a blockage recovery process for increasing a temperature of the DOC to a first temperature, if it is determined that the DOC is in the blockage risk state; a DPF forced regeneration condition determination part configured to determine whether a forced regeneration execution condition for the DPF is satisfied; a DPF forced regeneration execution part configured to execute a forced regeneration process for increasing a temperature of the DPF to a second temperature and increasing the temperature of the DOC to the first temperature, if the forced regeneration execution condition is satisfied; and a counter reset process part configured to reset the counter value after completion of the forced regeneration process by the DPF forced regeneration execution part.