Research On Bench Rapid Aging Cycle Of Vehicle Three-way Catalytic Converter

In recent years, the holding of passenger and commercial vehicles is increasing faster and faster, and a large number of construction machinery and equipments are adopted to meet the needs of urban construction and economy expanding, all of this seriously increased the negative effects of exhaust emissions, there's no denying that the ecological environment and human health are affected. Under the circumstances, various controlling measures are applied, coming to techniques: first, to improve the emission control level from the source, using high-quality fuel and electronic control fuel injection system is considered; second, to use three-way catalytic converters for exhaust gas aftertreatment.This paper studies the impact on aging process that resulted from three-way catalytic converter working conditions, and analyzes the rapid aging specifications on test bench reckoned with key factors. The three-way catalytic converters nowadays are still based on precious metals as main catalyst, under the condition of full ignition temperature, the conversion rate can reach 90% in general, post-treatment effect is remarkable. The aging process begins just when the catalyst is put into use, the problem is the aging degree need to be estimated, the key points now is to ensure the conversion rate at the same time to extend the service life. Catalytic converter in the actual working environment is deteriorated by many factors, such as high temperature sintering, the reduction of active catalyst caused by impact of alternating air-fuel ratio, catalyst poisoning, micro-channel blocking caused by reaction products, mechanical vibrations lead to catalytic converter damage, et cetera. In order to ensure the quality of emission control, the real-time monitoring of the conversion efficiency is necessary, generally, there're three ways:First, the Chinese Emission Regulation state III requires new vehicles must be equipped with OBD-â…¡(On-Board Diagnostics, a self-diagnostic system), and only to monitor pollution HC objects to determine the efficiency of catalytic converters, that means the converter should use dual-HC sensors to monitor the work conditions; second, due to catalytic converter reaction release heat, exhaust gas temperature goes up through the catalyst bed, we can use two temperature sensors to monitor the temperature rise; third, to determine the catalytic converter efficiency through comparing the electronic signals from pairs of oxygen sensor.Based on a lot of literature research, domestic common evaluation methods of the catalytic converter performance are studied in detail, from the reaction principle, the aging deterioration mechanism to the specific evaluation methods, a comprehensive analysis is placed, a certain amount of information acquired based on the test pattern is researched and the bench test system is established on which the engine uses GM 3.0L LZC, after ECM calibration, the engine would be used as a gas generator, the core component of the aging test. In the relevant assessments of catalytic converter performance, the most difficult is aging test and rapid aging on test bench has the most demanding conditions. There are many aging simulation models at home and abroad, each of programs proposed should have gone through lots of auto road tests as a base, so the aging pattern must keep unanimous with the original conditions, analysis of the actual use of catalytic converters in the natural aging mechanism is necessary, the engine is not equipped on vehicle, so the bench system design and testing process control is analyzes in depth, and the various aging factors associated with patterns of the rapid aging cycle are analyzed based on catalytic converter's reaction principle.