The gasoline engine catalyst technology plays a role of purifying the exhaust gases(HC, CO, NOx, PM) harmful to human and environment, generated from engine combustion in various cars using fuels such as gasoline, liquefied petroleum gas(LPG), natural gas(NG), etc., into harmless components(H2O, CO2, N2). The gasoline engine catalyst technology of Heesung Catalyst is endlessly researched, developed and commercialized based on excellent talents and accumulated experiences as a technology optimized for the kind, use position, purification object, purification method and engine operation condition of developed cars. In addition, Heesung Catalyst contributes to development of cutting-edge eco-friendly automobiles by developing and providing a technology needed by customers from the initial development stage through close communications with customers. The gasoline engine catalyst technologies of Heesung Catalyst include Three Way Catalyst(TWC) having been used traditionally, Gasoline Particulate Filter(GPF) to remove particulate substances, TWC Nox Trap, Lean NOx Trap(TWC-NT/LNT) which is a mileage improvement technology, Hydrocarbon Trap(HCT) to remove fuel hydrocarbon(HC) generated during a cold start, and Ultra Low PGM Catalyst.
Three way catalyst(TWC)
The three way catalyst(TWC) - where a ceramic or metallic substrate of various types of honeycomb appearance is coated with precious metals which is main active sites, supports to enhance degree of dispersion of precious metals even at a high-temperature operation condition, and promoters to reinforce the role of precious metals and supports - plays a role of purifying the unburned fuel(HC), carbon monoxide(CO) and nitrogen oxide(NOx) harmful to human, generated by incomplete combustion and high-temperature reaction of fuel in the engine combustion chamber of cars operated in a stoichiometric air-fuel ratio with fuel such as gasoline, LPG, CNG, etc., into harmless water(H2O), carbon dioxide(CO2) and nitrogen(N2) via an oxidation and reduction catalyst reaction.
Detailed information view
Starting with a two way catalyst having only an oxidation function to remove HC and CO in U.S. in later 1970s as the longest automotive exhaust gas purification catalyst, the three way catalyst(TWC) was created to simultaneously reduce HC, CO and NOx, three major pollutants discharged from gasoline cars, by introducing ceria(CeO2), facilitating the storage and discharge function of oxygen depending on atmosphere of exhaust gases, and its function to the catalyst in early 1980s. The three way catalyst(TWC) has been researched and developed to meet the endless internal and external requirements such as exhaust gas regulation reinforcement, catalyst material property enhancement, precious metal price change, new engine technology, etc. in each country thereafter. The three way catalyst(TWC) should endure the 240,000 Km(U.S. LEV-III), a legal guarantee distance, as well as purify the high-temperature exhaust gas discharged from engines operated at various environments, so it can be said that high-temperature durability is very important. The high-temperature durability is a necessary property directly connected with car mileage at a high-load condition as well as the lifespan of a three way catalyst, so it can be secured only after optimization of components, production methods and use environments of three way catalysts.
The Heesung Catalyst conducts the following researches to develop high-performance three way catalysts.
In addition, from 1970s, the precious metals, playing a role of main active point in automotive catalyst reactions, are limited in reserves and producing countries, so their price changes have ever been large and their stable supply and demand have ever been difficult depending on international political situations and market environments. The Heesung Catalyst is also constantly striving for R&D of a Ultra Low PGM TWC technology and a Non-PGM TWC technology to flexibly cope with these situation.
Gasoline Particulate Filter(GPF)
With a view to the gradually strengthening exhaust gas regulation, CO2 emission control, mileage improvement and output enhancement, gasoline cars are in an increasing rate of adopting a gasoline direct injection(GDI) method instead of the existing indirect injection(MPI) method. However, the direct fuel injection engine having many advantages comes to be low in fuel combustion uniformity at the cold start section and the high-speed high-load operation region due to the characteristics of fuel injection to get to emit a number of nano-size particulate substances at this time. The gasoline particulate filter(GPF) is a catalyst having a structure that a ceramic filter(wall-flow) in the alternately blocked porous channels is coated with catalyst components having a three way catalyst(TWC) function or another purpose function, and has a function of removing nano-size particulate substances discharged from gasoline direct injection(GDI) engines.
Detailed information view
The GPF is a porous ceramic filter(wall-flow) in the alternately blocked porous channels that is coated with catalyst components, whose primary function is to remove nano-size particulate substances(PN). And the use environment is almost equal to the three way catalyst(TWC), so the HC, CO, NOx purification function and the high-temperature durability required in TWC are equally necessary properties. GPF is also called a Four Way Catalyst(FWC) because it removes four pollutants such as HC, CO, NOx, PN like this. Especially, GPF's different properties from the three way catalyst(flow-through) with channels opened in a use environment are combustion of soot composing a particulate substance and sedimentation of ash, which have a direct impact on the function and durability of GPF. The Heesung Catalyst conducts a study on the catalyst components coated for upgrading of GPF technology, a study on the filter materials such as ceramic and metal, a study on the structure of ceramic filter pores, a study on the manufacturing method, a study on the soot combustion(recycling), and a study on the ash deposited in GPF as the use period increases and on the reduction of its impact.
The NOx Trap catalyst technology has core factors of three way catalyst components and NOx Storage Materials(NSM), and has a mechanism of storing the NOx not purified by a three way catalyst when an engine is operated in an oxidation atmosphere with much air and then removing it with a three way catalyst component near the stoichiometric air-fuel ratio. While general gasoline cars are designed to be operated at a stoichiometric air-fuel ratio condition(λ=1) to maximize the purification efficiency of three way catalysts, there are actively realized the R&D to increase the operation section to reduce fuel usage to reduce carbon dioxide(CO2) and improve mileage and the development of lean-burn engines operated in a lean fuel and much air condition, in which operation conditions there is however much air compared to the stoichiometric air-fuel ratio to discharge NOx not purified, so it is solved by a NOx Trap technology. Thus the NOx Trap technology can be regarded as a car mileage enhancement catalyst technology.
Detailed information view
The NOx Trap catalyst technology is mostly located under the floor away from the engine considering the NSM(NOx Storage Material) component's thermal resistance, NOx storage capacity and optimal working temperature range, and has been limited in use in a high-temperature exhaust gas operation environment. Differently from the integrity of the lean-burn engine technology, there is a limit in the post-treatment system to purify the NOx discharged in an oxidation atmosphere with high-temperature exhaust gas and much oxygen, so the lean-burn engine technology is not being widely expanded. The Heesung Catalyst has made an effort to develop and commercialize an optimized technology for the use environment by overcoming this disadvantage of the NOx Trap technology, and is constantly conducting a study on the NOx treatment capacity enhancement, heat-resisting temperature improvement and operation temperature range extension through development of new catalyst materials to expand the use of lean-burn engines in the future, improve mileage connected with reduction of CO2 emissions, cope with the strict exhaust gas regulations such as North American LEV-III using the property of the NOx Trap and prepare in advance for the demand for technologies such as compactification of exhaust gas purifiers(Close Coupled Converter Only).
The gasoline cars discharge much unburned fuel and incompletely-burned hydrocarbon, due to the low combustion chamber temperature and the inactivated three way catalyst during a cold start, whose quantity accounts for over 80% of the entire operation section when a car is operated in a FTP-75(Federal Test Procedure-75) mode, a domestic and North American exhaust gas certification travel mode. This is being solved through studies on the improvement of engine fuel control and combustion technology and the improvement of catalyst activation temperature, which is however still insufficient. The HC Trap technology is a technology to store the hydrocarbon(HC) discharged in the cold start section and then oxidize it on the catalyst when the catalyst temperature is raised and activated by using a substance such as zeolite whose fine pores are well developed with acid sites together with a three way catalyst(TWC).
Detailed information view
The HC Trap technology can be largely divided into an active type and a passive type; of which the active type is a technology to store HC by flowing the exhaust gases only to the HC Trap catalyst until the three way catalyst is activated in a cold start section using separate catalysts such as a HC Trap catalyst and a three way catalyst and using the valve control in a vent system and then to detach and discharge it after activation of the three way catalyst, whose effect is big but whose control device is complicated and whose cost and durability is in dispute, while the passive type is a method to remove HC without separate device by composing the HC Trap material as one catalyst together with the three way catalyst, whose exhaust system is not complicated but whose HC removal effect is not as large as the active type. In the background that two types of HC Trap technologies like this are created, the thermal durability and storage method of the HC Trap materials developed so far can be said to meet the expectations, and are commercially not largely being applied. The Heesung Catalyst is making an effort to develop a practical HC Trap catalyst technology through a study on the properties of HC molecules discharged a lot from the cold start section, the development of HC storage materials to increase chemisoprtion, and a study on the low-temperature activated three way catalyst.
Seoul office:39, 9-gil, Namdaemun-ro, Jung-gu, Seoul, Korea TEL. +82-2-3709-7777 FAX. +82-2-752-4437
Shihwa plant:91, Somanggongwon-ro, Siheung-si, Gyeonggi-do, Korea TEL. +82-31-496-5500 FAX. +82-31-433-7100
Dangjin plant: 28-76, 4-gil, Bugokgongdan, Songak-eup, Dangjin-si, Chungnam, Korea TEL. +82-41-356-8053 FAX. +82-41-356-8050
Copyright ⓒ HEESUNG CATALYSTS CORP. 2017. All Right Reserved