The world-wide commercial vehicle industry is faced with numerous challenges to reduce oil consumption and greenhouse gases, meet stringent emissions regulations, provide customer value, and improve safety. This work focuses on the new U.S. regulation of greenhouse gas (GHG) emissions from commercial vehicles and diesel engines and the most likely technologies to meet future anticipated standards while improving transportation freight efficiency.
In the U.S., EPA and NHTSA have issued a joint proposed GHG rule that sets limits for CO2 and other GHGs from pick-up trucks and vans, vocational vehicles, semi-tractors, and heavy duty diesel engines. This paper discusses and compares different technologies to meet GHG regulations for diesel engines based on considerations of cost, complexity, real-world fidelity, and environmental benefit. In addition, the paper describes powertrain integration aspects for vocational and semi-tractor engines with technologies including advanced SCR, waste heat recovery (Rankine) cycles and downspeeding. Innovation in component technology coupled with system integration is enabling engine manufactures to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a greater than 50% brake thermal efficiency (BTE) for the engine plus aftertreatment system.
