Abstract
This work focuses on the regulation of greenhouse gas emissions from commercial vehicles and heavy-duty diesel engines and the most likely technologies to meet future anticipated standards in the U.S. The U.S. Environmental Protection Agency (EPA) and National Highway Traffic Safety Administration (NTSHA) are developing the second phase of commercial vehicle GHG standards. In response, a comparative analysis of the current and alternative approaches to GHG regulation is presented based on considerations of cost, complexity, real-world fidelity and environmental benefit.
Vehicle level and component level (engine, transmission, and hybrid drivetrains) approaches to GHG regulations are examined for real-world drive cycles. From this assessment, a regulatory framework based on both vehicle power demand and engine (or powertrain systems) CO2 production is created as a means to combine both approaches and provide refinements as part of the second phase of GHG standards.
Using this regulatory framework, engine and powertrain technologies are evaluated using analytical models for engine, aftertreatment, and powertrain systems. The most promising technologies are validated with laboratory and vehicle testing. Engine and aftertreatment technologies are integrated to provide greater than 50% brake thermal efficiency (BTE) for a variety of engine duty cycles. This is compared to 44% BTE for current production diesel engines in the U.S. Combining the 50% BTE diesel engine with additional powertrain and vehicle technologies results in a greater than 50% improvement in freight efficiency for HD on-highway applications. The engine and powertrain technologies employed provide the customer with significant total cost of ownership (TCO) improvements. These technologies create roadmaps for GHG emissions reductions for the 2020 – 2025 timeframe that achieve the desired environmental impact. Further reduction of greenhouse gas emissions (GHGs) and fuel consumption through a second phase of regulation is important to addressing environmental needs, delivering cost savings to end-users and the economy and bringing new engine, powertrain and vehicle technologies to the commercial vehicle market.
KEYWORDS – Diesel Engine, Greenhouse Gas, Diesel Powertrains, Commercial Vehicles, Engine Efficiency