Particulate Control Technology and Particulate Standards for Heavy Duty Diesel Engines

Heavy-Duty diesel particulate emissions are presently the subjects of considerable regulatory concern. The U.S. Environmental Protection Agency (EPA) has proposed particulate standards for heavy-duty diesel truck and bus engines. As a result, particulate control technology for heavy-duty diesels is of increasing interest. This paper presents some preliminary findings from a current study of particulate control for heavy-duty diesel engines. It surveys the present state of the technology, with particular attention to trap-oxidizers. The special requirements for trap-oxidizers in heavy-duty service are described, and the problems in adapting the trap-oxidizer technologies developed for light-duty diesels to heavy-duty engines are discussed. Cost estimates for potential heavy-duty fuel-oxidizer systems are developed. The paper also briefly discusses the potential for in-cylinder control of NO_x and particulates, and the trade-off between NO_x and particulate emissions. A concluding section deals with some of the implications of these findings for regulatory action.