輕油 粒子狀物質 濾過裝置의 排氣低減性能에 關한 硏究

Abstract

As the motor vehicle emission regulation becomes stricter due to the accelerated global warming and air pollution all over the world, diesel engine which has high efficiency and low CO2 emission is being revaluated as the solution. But diesel engine has disadvantage in high toxic emissions such as Particulate Matter(PM) and NOx which are very difficult to reduce simultaneously. Although diesel emission control technology such as precise injection timing control, a common-rail high pressure fuel system and an alternative fuel has been improved, the diesel engine is still difficult to meet the future regulation which is stricter than EURO 5. Since it is quite difficult to meet post-EURO 5 regulation with pre-processing technology such as improvement of engine performances, aftertreatment technology such as Diesel Particulate Filter(DPF) or Selective Catalyst Reduction(SCR) should be developed to reduce PM and NOx. Although the strict management of newly manufactured motor vehicles is important, the management of in-use diesel vehicles, especially in metropolitan region where a large number of motor vehicles are running, is another important factor for controlling air pollution. Trying to reduce the emissions of PM, Korean Ministry of Environment(MOE) has implemented the retrofit program which has installed the Diesel Oxidation Catalyst(DOC) and DPF in light-duty and heavy-duty diesel vehicles, respectively. When DPF for heavy duty vehicles is applied to medium and light duty vehicles such as county buses, the regeneration efficiency and the performance and fuel consumption efficiency of motor vehicles are getting down. So in order to reduce the emissions from medium duty truck which is difficult to apply DPF, the Partial Diesel Particulate Filter(PDPF) which has better motor vehicle performances and fuel consumption efficiency than DPF by reducing the resistance of exhaust flow and the load to engine or motor vehicle instead of lowering PM filtering efficiency by 50~60% with opening PDPF passage, was developed and the performance evaluation was also carried out. PDPF uses the corrugated layer blades which have three dimensional geometry and captures particulate matter by making some part of exhaust gas pass through porous fleece layer. For the evaluation for PDPF, reduction efficiency test, durability test, property test and smoke test(Lug down 3 mode) were executed. PDPF reduced 56.3% of PM, 98.3% of CO, 93.6% of HC and 4.3% of NOx in ND-13 emission mode test. PDPF slightly affected maximum engine power and fuel consumption efficiency, but did not exceed the standard value of 5%. In property test before and after DPF set up, the difference of emission reduction efficiencies and the variation of temperature and pressure in up-and-down streams of PDPF is negligible. With these property test results, the performance of durability could be confirmed. In the Lug Down 3 mode test under the condition of 100, 90, 80% of engine rated speed using engine dynamometer, PDPF has shown smoke reduction of 50.4% in smokemeter and 54.4% in opacimeter, which confirms over 50% reduction efficiency in both smoke measurement methods. Because PDPF has higher durability and safe performance than DPF for heavy duty trucks of which main driving cycles are low speed and high load, PDPF technology could be available to the medium and heavy duty vehicles that DPF could not be applied to.