KR-102962258-B1 - DEVICE FOR PURIFYING EXHAUST GAS AND METHOD OF CONTROLLING THE SAME

KR102962258B1KR 102962258 B1KR102962258 B1KR 102962258B1KR-102962258-B1

Abstract

An exhaust gas purification device according to one embodiment of the present invention is an exhaust gas purification device configured to purify the exhaust gas of an engine, comprising a warm-up catalytic converter (WCC) installed in an exhaust line and an under-floor catalytic converter (UCC) installed downstream of the warm-up catalytic converter, wherein the under-floor catalytic converter comprises an HC adsorption catalyst that selectively adsorbs or desorbs hydrocarbons (HC) depending on the temperature of the exhaust gas, and a three-way catalyst (TWC) disposed downstream of the HC adsorption catalyst and purifying the HC desorbed from the HC adsorption catalyst.

Inventors

강천용

Assignees

현대자동차 주식회사
기아 주식회사

Dates

Publication Date: 20260508
Application Date: 20200611

Claims (12)

In an exhaust gas purification device configured to purify the exhaust gas of an engine, Warm-up Catalytic Converter (WCC) installed in the exhaust line; An under-floor catalytic converter (UCC) installed downstream of the warm-up catalytic converter; and It includes a control unit that controls the concentration of unburned fuel contained in the exhaust gas to a rich state in the catalytic heating region during cold start, and after a certain period, controls the concentration of unburned fuel contained in the exhaust gas to a lean state to desorb hydrocarbons (HC), and if the temperature of the exhaust gas is above a set temperature, controls the concentration of unburned fuel contained in the exhaust gas to periodically repeat between the rich state and the lean state. The above under-floor catalytic converter is, An HC adsorption catalyst that selectively adsorbs or desorbs the HC depending on the temperature of the exhaust gas; and An exhaust gas purification device comprising a three-way catalyst (TWC) disposed downstream of the HC adsorption catalyst and purifying the HC desorbed from the HC adsorption catalyst.
In Article 1, The above HC adsorption catalyst is an exhaust gas purification device comprising an ion-exchanged metal.
In Paragraph 2, The above ion-exchanged metal is, An exhaust gas purification device selected from at least one of precious metals such as Pt, Rh, Pd, and Au, or transition metals such as Cu, Fe, Mn, and Co.
In Article 1, The above HC adsorption catalyst is an exhaust gas purification device comprising a carrier having a slower heat transfer rate and a larger heat capacity than the above three-way catalyst.
In Article 1, The above HC adsorption catalyst is, Exhaust gas purification device including an LTA zeolite catalyst.
In Paragraph 5, The LTA zeolite catalyst included in the above HC adsorption catalyst is, An exhaust gas purification device made of either aluminum titanate or silicon carbide (SiC).
In Article 1, The above three-way catalyst is, Exhaust gas purification device made of cordierite material.
In Article 1, An exhaust gas purification device in which the above HC adsorption catalyst and the above three-way catalyst are formed as a single block.
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In Article 1, An exhaust gas purification device having a lambda value of 1.05 to 1.1 in the lean state.
Step of starting the engine; A step of controlling the concentration of unburned fuel contained in the exhaust gas to a rich state in the catalytic heating region during cold start; A step of controlling the concentration of unburned fuel contained in the exhaust gas to a lean state after a certain period of time has elapsed; A step of determining whether the temperature of the exhaust gas is above a set temperature; and A method for controlling an exhaust gas purification device comprising the step of controlling the concentration of unburned fuel contained in the exhaust gas to periodically alternate between a rich state and a lean state when the temperature of the exhaust gas is above a set temperature.
In Paragraph 11, A method for controlling an exhaust gas purification device in which the lambda value of the lean state is 1.05 to 1.1.

Description

Device for Purifying Exhaust Gas and Method of Controlling the Same The present invention relates to an exhaust gas purification device and a method for controlling the same, and more specifically, to an exhaust gas purification device and a method for controlling the same that can reduce harmful substances in exhaust gas by controlling lambda in the catalyst heating region of the cold start section using an HC adsorption catalyst containing an ion-exchanged metal. Generally, vehicles generate the power necessary for driving by burning fuel using an engine. The process of fuel combustion using an engine inevitably produces combustion gases, and these combustion gases (exhaust gases) are released into the atmosphere through the exhaust system. Recently, as interest in the global environment has grown, much research and development is underway to reduce harmful substances contained in exhaust gases emitted from vehicles. In particular, much effort is being made to reduce particulate matter and nitrogen oxides (NOx), which are particularly harmful to the global environment, among the exhaust gases emitted from diesel or gasoline engines used in vehicles. Filters and catalysts are typically used to reduce harmful substances contained in exhaust gas, such as the above-mentioned particulate matter and nitrogen oxides. As an example, a three-way catalytic converter can almost perfectly purify substances harmful to the human body, such as hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides emitted from the engine, when the exhaust gas temperature is 400°C or higher. However, it has the disadvantage that its purification performance deteriorates during the cold start phase of the vehicle, resulting in the emission of a large amount of harmful substances. To reduce harmful substances in exhaust gas during the cold start phase of the vehicle, zeolite-based hydrocarbon adsorption catalysts (HC Trap) and nitrogen oxide adsorption catalysts (NOx Trap) were introduced. However, most zeolite-based adsorption catalysts lacked high-temperature resistance and were placed in an under-floor catalytic converter (UCC) together with a three-way catalyst, and there was a difficulty in that HC and NOx were desorbed before the three-way catalyst was activated due to the slow warm-up speed of the three-way catalyst. FIG. 1 is a schematic diagram illustrating an exhaust system to which an exhaust gas purification device according to one embodiment of the present invention is applied. FIG. 2 is a schematic diagram illustrating the structure of an exhaust gas purification device according to one embodiment of the present invention. FIG. 3 is a flowchart illustrating a method for controlling an exhaust gas purification device according to an embodiment of the present invention. FIG. 4 is a graph showing the exhaust gas purification effect at lambda 1 compared with a mass-produced catalyst when using an HC adsorption catalyst in an exhaust gas purification device according to one embodiment of the present invention. FIG. 5 is a graph showing the exhaust gas purification effect according to lambda when an HC adsorption catalyst is used in an exhaust gas purification device according to one embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. In addition, in various embodiments, components having the same configuration are described using the same reference numerals, and in one representative embodiment, only configurations different from one embodiment are described. It should be noted that the drawings are schematic and not drawn to scale. The relative dimensions and proportions of parts in the drawings are exaggerated or reduced in size for clarity and convenience in the drawings, and any dimensions are merely illustrative and not limiting. Additionally, the same reference numeral is used to denote similar features for the same structure, element, or part appearing in two or more drawings. Where one part is referred to as being "on" or "on" another part, it may be directly on top of the other part or may enclose other parts in between. The embodiments of the present invention specifically illustrate one embodiment of the present invention. As a result, various variations of the illustration are expected. Accordingly, the embodiments are not limited to the specific form of the illustrated area and include, for example, variations in form resulting from manufacturing. The exhaust gas purification device according to an embodiment of the present invention can be applied not only to vehicles but also to various devices that obtain energy by burning fossil fuels and discharge the gases generated in the process into the atmosphere. Although