Diesel Particulate Filter Soot Estimation and Regeneration Control
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Solution Overview
Problem
Existing exhaust gas purification systems for diesel engines face challenges in accurately determining the timing for starting and ending active regeneration of diesel particulate filters (DPFs), leading to potential over-accumulation of soot, frequent regenerations, and increased fuel consumption and oil dilution, especially in off-road vehicles with varying engine operation states.
Innovation Solution
An exhaust gas purification apparatus that includes a pre-oxidation catalyst, a particulate filter, a heating device, and calculation units to estimate soot accumulation based on engine operation state, total operation time, fuel consumption rate, and pressure difference, allowing for precise determination of regeneration timing and prevention of over-accumulation by correcting soot accumulation amounts and updating regeneration periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active regeneration is performed frequently to prevent soot over-accumulation, then soot removal reliability is improved, but fuel consumption increases and oil dilution worsens
Solution Approach 1:
The system uses multiple feedback mechanisms including pressure difference sensors to monitor DPF backpressure, oxygen sensors to detect exhaust composition changes, and calculation units that continuously estimate soot accumulation based on engine operating parameters. This multi-parameter feedback enables precise determination of regeneration timing, avoiding both premature and delayed regeneration, thus preventing unnecessary fuel consumption while ensuring reliable soot removal
Solution Approach 2:
The system changes operational parameters dynamically by adjusting regeneration timing and duration based on real-time monitoring of pressure difference, oxygen concentration, and engine operating conditions. The control unit modifies regeneration parameters (such as fuel injection timing and amount during regeneration) according to the accumulated soot level and current engine state, optimizing the balance between soot removal effectiveness and fuel consumption
2Loss of energy
If regeneration timing is delayed to reduce fuel consumption, then fuel efficiency is improved, but soot accumulation increases risking DPF melting
Solution Approach 1:
The system continuously monitors multiple parameters including pressure difference across the DPF, oxygen sensor readings, and engine operating conditions to provide real-time feedback on soot accumulation status. This enables the control unit to detect approaching dangerous accumulation levels and initiate regeneration at the optimal moment, preventing DPF melting while minimizing fuel consumption
Solution Approach 2:
The system performs preliminary estimation of soot accumulation using calculation units that process engine operating parameters before actual regeneration is needed. By predicting soot accumulation trends based on current operating conditions and historical data, the system can prepare for and initiate regeneration at the optimal time, preventing dangerous accumulation while avoiding premature regeneration
3Measurement precision
If multiple estimation indexes are used to determine regeneration timing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it monitors engine operating parameters, estimates soot accumulation using multiple indexes, determines optimal regeneration timing, controls fuel injection during regeneration, and adjusts regeneration duration. This multi-functional design consolidates what could be separate systems into a single control unit, improving measurement precision through multiple estimation approaches while minimizing the increase in device complexity
Solution Approach 2:
The system combines multiple estimation approaches (pressure difference-based estimation, oxygen sensor-based estimation, and engine parameter-based calculation) into a unified soot accumulation assessment system. By merging these different measurement methods and integrating them with engine control functions, the system achieves high measurement precision while avoiding the complexity of completely separate monitoring and control systems
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 solution enhances the precision of soot accumulation estimation, ensures complete removal of soot, and prevents oil dilution by optimizing regeneration timing and frequency, thereby improving the reliability and efficiency of the regeneration process.
Implementation Method 1
a pre-oxidation catalyst which burns an unburned constituent contained in exhaust gas of an engine by catalysis
Implementation Method 2
a heating device which increases an amount of the unburned constituent to be supplied to the pre-oxidation catalyst to perform a active regeneration of the particulate filter
Implementation Method 3
a particulate filter which is arranged downstream of the pre-oxidization catalyst to collect soot contained in the exhaust gas
Data Source
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AI summary
An exhaust gas purification apparatus is provided with: a first soot-accumulation calculation unit 49 which calculates a first soot accumulation amount from an operation state of the engine; a second soot-accumulation calculation unit 51 which calculates a second soot accumulation amount from a total operation time of the engine, a total fuel consumption rate, a pressure difference between front and back of the particulate filter, and the like; a first soot-accumulation correction unit 55 which corrects the first soot accumulation amount calculated by the first soot-accumulation calculation unit 49 to a value greater than the first soot-accumulation amount when the active regeneration starts based on the second soot accumulation amount calculated by the second soot-accumulation calculation unit 51; and a regeneration ending unit 57 which ends the active regeneration when, in such a case that the active regeneration starts based on the corrected soot accumulation amount, the first soot accumulation amount becomes less than a threshold value of ending the regeneration.