Integrating New Emissions Engines Into Commercial Vehicles: Emissions, Performance Affordability

摘要

Commercial vehicles carry more than 10 billion tons of goods - approximately 70 percent of all freight shipped - and travel over 450 billion miles each year in the United States. These vehicles are the exclusive mode of delivery in over 75 percent of U.S. communities. Such utilization and dependency demand commercial vehicles be reliable, durable, and cost effective. The heart of these commercial vehicles (Classes 3-8) is the diesel engine. The widespread use of the diesel engine can be attributed to its reliability, durability, and cost effectiveness. However, the 2007 and 2010 EPA emissions regulations are creating significant challenges for diesel-powered commercial vehicles. Engine and vehicle manufacturers must strike a balance between emissions, performance, and affordability. A consequence of the evolution of the diesel engine to meet the increasingly stringent emissions regulations is that more effort to accommodate the associated changes is driven to the vehicle manufacturers. However, a result of this engine evolution is that commercial vehicles are now more environmentally-friendly as part of the vehicle evolution to become safer, more productive, ergonomic, and driver-friendly. The diesel engine touches many of the vehicle's systems, sub-systems, and components, all of which have to be analyzed for direct and indirect influence from associated engine changes. When these changes include new technologies at the vehicle level, as is the case for 2007 with active exhaust aftertreatment, implementation for the vehicle manufacturer becomes even greater. The purpose of this paper is to provide a comprehensive exposure to the numerous tasks and challenges associated with changes to diesel engines and related vehicle systems imposed by regulatory mandates. An historical perspective on the levels of effort associated with previous emissions regulations is offered to emphasize the level of effort required to support the 2007 Diesel Engine Emissions Regulations. Attaining the overall goal of implementing the 2007 changes in production requires a systematic engineering approach from assessing customer requirements to delivering products that meet these requirements. Elements of program management, product management, timing, overlapping programs, new considerations in trade-off decisions, higher levels of integration, higher levels of analysis, higher levels of verification, and collaboration of extended resource teams are examined as well as an exploration of potential implications for future emissions reduction technologies.