This project belongs to the field of transportation engineering. Fine particulate pollution, represented by PM2.5, is the most severe atmospheric environmental issue currently facing China. Vehicle exhaust emissions are the primary source of atmospheric PM2.5, contributing up to 25% to 30%. Diesel vehicles are the main contributors to particulate matter in motor vehicles, with a contribution rate as high as over 90%. Effectively controlling particulate emissions from diesel vehicles, especially heavy-duty diesel vehicles, is of great significance for reducing motor vehicle pollutant emissions and improving regional air quality. Supported by the Shanghai Science and Technology Innovation Plan and other projects, this project has undergone more than a decade of 'industry-academia-research-application' joint research and development. Focusing on the particulate emission control issues of heavy-duty diesel vehicles, especially diesel buses, it takes into account the significant differences in emission levels between different types of buses in China and their frequent starting and stopping during actual operation. Breakthroughs in the key technologies of catalyst, carrier, and engine matching for DOC combined with catalytic particulate filter (CDPF) have been achieved, leading to independent development of an efficient DOC+CDPF particulate aftertreatment device. The project outcomes are as follows: (1) Independent development of a DOC+CDPF catalyst with high low-temperature activity and sulfur resistance stability. Invention of an oxidation catalyst for purifying diesel engine exhaust gases with good ignition characteristics (T50 below 200°C) and high sulfur resistance properties (for diesel fuel standards III and above); overcoming technical difficulties such as continuous regeneration and thermal stability of particles at low temperatures (210~250°C) in CDPF, inventing a diesel engine continuous regeneration black smoke particle filtration system. (2) Successful development of a flow field characteristic that is conducive to the effective separation of particulate matter and gas phase. A DOC+CDPF particulate aftertreatment carrier with high capture efficiency for ultrafine particles and a low backpressure catalyst coating technology have been invented. A non-conventional end-face carrier suitable for diesel particulate purification has been developed, which improves the utilization rate and service life of the catalyst inside the carrier; advanced catalyst coating technology has been researched and developed, and an all-automatic quantitative honeycomb carrier catalyst coating equipment has been invented, achieving low backpressure performance (effective reduction of 20% in backpressure) and high coating efficiency. (3) The matching technology between the DOC+CDPF particulate aftertreatment device and heavy-duty diesel engines has been overcome. The optimization of the in-cylinder fuel post-injection strategy for diesel engines has increased exhaust temperature, effectively improving the regeneration reliability and adaptability of the particulate aftertreatment device; a bus-specific DOC+CDPF diesel engine exhaust purification system based on actual urban road conditions has been invented, breaking through the challenge of regenerating the particulate aftertreatment device under low-temperature conditions for the entire vehicle. Achieve a reduction of more than 90% in particulate mass emissions and more than 95% in particulate number emissions from diesel engines. (4) Created the first 'particulate after-treatment catalyst - after-treatment carrier and device - heavy-duty diesel engine matching - real vehicle road verification and scale application' industrial chain technology platform in China. Formulated a standard system for the use, maintenance, and upkeep of particulate after-treatment technology devices, including design of appearance and interface ends, technical transformation processes, supervision during assembly process, maintenance. Took the lead in Shanghai to carry out an application demonstration of installing particulate after-treatment technology devices on national III diesel buses. The research results of this project have applied for 11 invention patents, granted 4 invention patents, and authorized 1 utility model patent. Published 29 papers, including 4 in SCI and 13 in EI. Trained 2 doctoral students and 10 master's students. The project's achievements have been widely applied in companies such as Wuxi Weifu Environmental Protection Catalyst Co., Ltd., Shanghai Chuangyi Environmental Technology Co., Ltd., and Shanghai Bus Public Transport (Group) Co., Ltd. In the past three years, there has been an increase of 576 million yuan in sales revenue, 52.58 million yuan in profit, and 25.25 million yuan in tax revenue. The project's achievements have been widely used on Shanghai's urban diesel buses, effectively reducing the particulate matter emissions from these vehicles. If the project's achievements are applied to nearly 180,000 diesel buses in major cities across the country, it could reduce about 15% of the particulate matter emissions from motor vehicles each year, providing an important guarantee for China's PM2.5 reduction targets in key areas, with significant social benefits. This achievement is not only applicable to diesel buses but can also be promoted to other diesel engine application fields such as diesel trucks and construction machinery.