Plasma Reactor Heats Exhaust Gas for DPF Regeneration
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Solution Overview
Problem
Current diesel particulate filter (DPF) technologies face challenges in effectively regenerating particulate materials at low exhaust gas temperatures, particularly in city buses and small diesel vehicles, due to high costs and operational complexities of active and passive regeneration methods.
Innovation Solution
A plasma reactor system that heats exhaust gas before it reaches the DPF trap, using liquid fuel reformulated into pre-oxidation materials like hydrogen and carbon monoxide, to facilitate efficient oxidation and regeneration of particulate materials, while improving gas and liquid mixing for reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If passive regeneration method is used to lower PM oxidation temperature from 650°C to 300°C using catalysts or additives, then oxidation temperature is reduced, but the method cannot be applied to city buses and small diesel vehicles where exhaust gas temperature is below 250°C
Solution Approach 1:
The patent introduces a plasma reactor that performs preliminary heating of exhaust gas before it reaches the DPF trap. By pre-heating the exhaust gas to above 250°C using plasma discharge, the system ensures that the temperature is sufficient for effective PM oxidation even in low-temperature operating conditions typical of city buses and small diesel vehicles.
Solution Approach 2:
The plasma reactor serves as an intermediary device between the exhaust gas source and the DPF trap. It mediates the temperature issue by converting electrical energy to thermal energy through plasma discharge, thereby raising the exhaust gas temperature to a level suitable for passive regeneration without requiring high-temperature active regeneration systems.
2Productivity
If active regeneration method using electric heater is applied to heat exhaust gas for PM oxidation, then regeneration effectiveness is improved, but the cost of required electric power becomes excessively high
Solution Approach 1:
The patent replaces the conventional electric heater system with a plasma reactor system. Instead of using resistive heating elements that consume excessive electrical power, the system uses plasma discharge to generate heat. This substitution maintains regeneration effectiveness while significantly reducing electrical power consumption by utilizing a different physical mechanism for heat generation.
Solution Approach 2:
The patent changes the method of heat generation from resistive heating to plasma discharge. By altering the physical parameter of heat generation mechanism, the system achieves the same temperature rise effect with much lower electrical power input, as plasma processes are more energy-efficient for high-temperature generation compared to conventional electric heaters.
3Device complexity
If simple structure burner is used for active regeneration, then device complexity is reduced, but it is difficult to control operation according to oxygen condition in exhaust gas
Solution Approach 1:
The plasma reactor system incorporates sensors and control mechanisms that monitor oxygen concentration and other exhaust gas parameters in real-time. Based on this feedback, the system automatically adjusts plasma discharge parameters such as power input and gas flow rates to optimize PM oxidation efficiency under varying operating conditions, thereby achieving both simplicity and controllability.
4Temperature
If throttling or fuel additive injection is used to lower oxidation temperature at catalyst, then oxidation temperature is reduced, but additional devices are needed and secondary contamination may occur
Solution Approach 1:
The patent extracts and removes the need for throttling devices and fuel additive injection systems by using plasma discharge as an alternative method to lower oxidation temperature. The plasma reactor directly heats the exhaust gas and promotes low-temperature oxidation through plasma-induced chemical reactions, eliminating the requirement for additional throttling mechanisms or fuel additive 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
The plasma reactor system enables effective and prompt oxidation of particulate materials, ensuring successful regeneration even at low temperatures, reducing environmental pollution and simplifying operational conditions.
Implementation Method 1
a plasma reactor which reforms the liquid fuel to the pre-oxidation material, in which a part of the liquid fuel is evaporated and mixed with the exhaust gas and the mixed gas is plasma-reacted
Implementation Method 2
a part of the liquid fuel is evaporated and mixed with the exhaust gas
Implementation Method 3
the filter may oxidize and remove the collected particulate materials
Data Source
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AI summary
A reduction system for particulate materials in exhaust gas, which is connected to a tailpipe of an engine that burns a hydrocarbon-based fuel supplied from a fuel storage tank, and collects and removes particulate materials within the exhaust gas, may include a plasma reactor having a gas inlet and an outlet, and a DPF (diesel particulate filter) trap having a filter. The tailpipe of the engine may communicate with the gas inlet of the plasma reactor, and the outlet of the plasma reactor may communicate with the DPF trap. The exhaust gas exhausted from the engine may be transferred to the DPF trap after being heated while passing through the plasma reactor.