DPF Regeneration Control Unit for Exhaust Gas Purification
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Solution Overview
Problem
Exhaust gas purification systems using exhaust pipe injection for DPF regeneration face instability in temperature rise control, leading to potential incomplete regeneration and increased fuel consumption, especially in conditions like traffic jams, and may result in endless injection attempts when device failures occur, affecting gas mileage.
Innovation Solution
The system incorporates a DPF regeneration control unit with regeneration non-completion and malfunction warning mechanisms, which integrates regeneration time and monitors exhaust pipe injection amounts to determine successful completion or failure, aborting regeneration if the injection exceeds limits and triggering warnings for non-completion or malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If exhaust pipe injection is used for DPF regeneration, then PM removal efficiency is improved, but temperature rise control stability deteriorates
Solution Approach 1:
The system implements feedback control by continuously monitoring exhaust gas temperature through temperature sensors and adjusting the exhaust pipe injection amount accordingly. The ECU compares the actual temperature with the target temperature and modifies the injection rate to maintain stable temperature control during DPF regeneration, resolving the instability issue while preserving PM removal efficiency.
2Reliability
If exhaust pipe injection amount is increased to ensure PM combustion, then regeneration completeness is improved, but fuel consumption increases
Solution Approach 1:
The system applies partial action by injecting fuel only to the extent necessary for DPF regeneration rather than continuous excessive injection. The ECU calculates the minimum required injection amount based on PM accumulation levels and monitors regeneration progress, stopping injection once regeneration is complete. This ensures reliable PM removal while minimizing unnecessary fuel consumption.
Solution Approach 2:
The system utilizes the heat generated by PM combustion itself to maintain regeneration temperature, reducing the need for continuous external fuel injection. The exothermic oxidation of PM provides self-sustaining heat that keeps the exhaust gas temperature above the PM combustion point, allowing the system to maintain regeneration completeness with minimal additional fuel input.
3Reliability
If DPF regeneration is continuously attempted despite failure, then PM removal reliability is improved, but gas mileage deteriorates
Solution Approach 1:
The system performs preliminary checks before initiating DPF regeneration by monitoring differential pressure across the DPF and estimating PM accumulation levels. The ECU determines whether regeneration is actually needed based on these preliminary assessments, avoiding unnecessary regeneration attempts that would waste fuel and harm gas mileage while ensuring regeneration is performed when genuinely required for PM removal.
Solution Approach 2:
The system implements feedback monitoring during regeneration attempts by tracking exhaust gas temperature, injection amount, and regeneration time. If the system detects that regeneration is not progressing (temperature not reaching target, injection amount exceeding limits), it automatically aborts the operation and prevents repeated futile attempts, thereby maintaining PM removal reliability while protecting gas mileage from deterioration due to excessive fuel consumption.
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 appropriate abortion of DPF regeneration to prevent gas mileage decline during unstable temperature rise conditions and alerts the driver to potential malfunctions, ensuring safe and efficient regeneration.
Implementation Method 1
by combustion of a fuel component thereof with the DOC, a temperature of the exhaust gas flowing out from the DOC is raised to a target regeneration temperature
Implementation Method 2
exhaust pipe injection in which unburnt fuel is added from an exhaust pipe injector provided at an exhaust pipe between an engine and a DPF to exhaust gas discharged from the engine
Data Source
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Figure 2
AI summary
Provided is an exhaust gas purification system which is capable of appropriately aborting DPF regeneration to suppress a decline in gas mileage in a vehicle condition where temperature rise control of exhaust gas becomes unstable when the DPF regeneration is performed using exhaust pipe injection. The exhaust gas purification system includes a DPF 25 which collects PM in exhaust gas, an exhaust pipe injector 38 which performs exhaust pipe injection, and a DPF regeneration control unit 100 which performs temperature rise control of an exhaust gas temperature by the exhaust pipe injection to regenerate the DPF 25 when the PM collected by the DPF 25 exceeds a fixed amount and which, during the regeneration, integrates an amount of time during which the exhaust gas temperature exceeds a PM combustion temperature and completes the regeneration when an integrated value thereof reaches a set regeneration completion value. The DPF regeneration control unit 100 aborts the regeneration when, during the regeneration, a total amount of the exhaust pipe injection exceeds an exhaust pipe injection upper limit before the integrated value of the amount of time during which the exhaust gas temperature exceeds the PM combustion temperature reaches the set regeneration completion value.