Exhaust Gas Purification Device Upstream Turbocharger DPF
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Solution Overview
Problem
Recent diesel engines face challenges in maintaining exhaust gas temperature for continuous DPF regeneration and NOx purification efficiency due to lower exhaust gas temperatures, leading to increased regeneration frequency and reduced NOx purification efficiency, especially under cold conditions, and existing solutions complicate installation, increase weight, and cost.
Innovation Solution
An exhaust gas purification device with multiple upstream DOCs, a downstream DOC and DPF located between the exhaust manifold and turbocharger, a urea spraying nozzle between the downstream DOC and DPF, and an SCR unit downstream of the turbocharger, utilizing catalysts with OSC and noble metals for efficient CO and HC purification, and ammonia generation for NOx reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the DPF is located downstream of the turbocharger, then the exhaust gas flow is stabilized, but the exhaust gas temperature drops below the regeneration threshold
Solution Approach 1:
The DPF is positioned upstream of the turbocharger to perform PM filtration before the exhaust gas passes through the turbine. This preliminary action allows the DPF to receive hotter exhaust gas directly from the engine, maintaining temperatures above the 250-500°C regeneration threshold without requiring additional heating measures.
2Productivity
If the exhaust gas temperature is low, then fuel efficiency is improved, but the DPF regeneration frequency increases and NOx purification efficiency drops
Solution Approach 1:
The patent changes the spatial arrangement parameter by positioning the DPF upstream of the turbocharger. This parameter change ensures that the DPF receives exhaust gas at a higher temperature (above 250-500°C), enabling continuous regeneration without requiring increased fuel injection for heating, thus maintaining fuel efficiency while ensuring reliable regeneration.
3Volume of moving object
If the DPF is downsized, then installation space and weight are reduced, but the exhaust gas temperature may drop
Solution Approach 1:
By positioning the DPF upstream of the turbocharger, the system performs PM filtration before the exhaust gas undergoes expansion and cooling in the turbine. This preliminary action allows the use of a compact DPF design that still receives sufficiently hot exhaust gas for regeneration, achieving both downsizing and temperature maintenance.
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 configuration maintains higher DPF temperatures, extends regeneration intervals, allows for downsizing, reduces CO2 emissions during regeneration, and enhances NOx purification efficiency while minimizing DPF clogging and EGR path length, effectively utilizing exhaust heat.
Implementation Method 1
The exhaust gas which is discharged from the turbine 15 and flows in the exhaust pipe 20 is processed by the upstream oxidation catalyst (DOC) 24 to eliminate (purify) CO and HC from the exhaust gas, oxidize NO
Implementation Method 2
processed by the downstream DPF 25 to collect and remove the PM
Implementation Method 3
the urea contained in the urea water injected from the urea spraying nozzle 28 is hydrolyzed to NH3 by the SCR unit 27
Implementation Method 4
NH3 facilitates the reduction (deoxidization) of NOx in the exhaust gas to nitrogen and oxygen to purify the exhaust gas (NOx purification)
Implementation Method 5
burn the PM accumulated in the DPF 25, i.e., the regeneration of the DPF is performed
Data Source
Figure 1~2
Figure 3(a)~3(c)
Figure 4~5
AI summary
Provided is an exhaust gas purification device that can elevate the exhaust gas temperature on the inlet side of a DPF (diesel particulate filter). The exhaust gas purification device includes a DOC (oxidation catalyst) (31) and the DPF (32) that are arranged in an exhaust path (30) between exhaust ports (30p) of an engine (10) and a turbocharger (13). The exhaust gas purification device also includes a urea spraying nozzle (33) arranged on the upstream side of the DPF (32), and an SCR (selective catalytic reduction) unit (34) arranged in an exhaust pipe on the downstream side of the turbocharger (13).