Diesel Technology Developments
Aaron Isenstadt and John German
Highlights important innovations and trends in diesel engines and emission control systems, some of which were not considered when the 2025 CAFE and greenhouse gas standards were finalized, yet promise to improve diesel passenger vehicles’ cost-effectiveness, especially for larger classes.
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In the analyses for the 2025 corporate average fuel economy (CAFE) and greenhouse gas standards, the U.S. Environmental Protection Agency and the National Highway Traffic Safety Administration projected that diesel engines would have little place in the 2025 vehicle fleet.
Although diesel vehicles have come under great scrutiny recently, a number of technological improvements have led to solutions to many challenges faced by diesels, especially pollutant emissions. Many of these, and other, innovations are resulting in better-performing and less costly diesel options, particularly when compared to hybrid alternatives for larger vehicle classes. Example technologies include better turbochargers, engine downsizing and downspeeding, higher pressure fuel lines and more capable injectors, cooled exhaust gas recirculation, reduced-cost aftertreatment devices, and 48V electrical systems with electric boosting.
Thus, diesels may offer manufacturers another tool in their arsenal for producing 2025-compliant vehicles. The prevalence of diesel vehicles in the fleet will vary from manufacturer to manufacturer and model to model, as both automakers and consumers weigh the costs and benefits of diesels compared to their rapidly-improving gasoline counterparts.