Fuel systems for heavy-duty diesel engines have come a long way over the last decade since the advent of federally mandated exhaust emissions standards. Their evolution will continue over the next couple of years as new greenhouse gas regulations come into play. GHG emissions regulations also will be de facto fuel economy standards for heavy-duty trucks, and OEMs will rely heavily on computer-controlled fuel injection.
While fuel systems will continue to play an increasing role in emissions control and overall vehicle fuel economy, the next generation of these engine components doesn’t face major redesigns or significant changes. At the same time, minor tweaks made by OEMs to these systems hold great promise in yielding increased fuel economy benefits.
“While fuel system changes are not a requirement to meet the next generation of GHG diesel engine regulations, we are pursuing opportunities to improve fuel system efficiencies and further optimize engine performance,” says Roy Horton, director of product marketing for Mack Trucks.
Fuel systems will have improved control characteristics designed to enable precise combustion timing, which will help achieve emissions requirements and improved fuel economy, Horton says. They “will be a cornerstone of future engine design,” he says.
Brad Williamson, marketing communications manager for Daimler’s Detroit powertrain brand, says the next generation of fuel systems will not necessarily be more complex than today’s systems. “We can expect that fuel pressures will continue to go up to allow for better control of fuel delivery,” Williamson says.
To accomplish this, further shaping of combustion events will be required to control them better and make them more precise, contributing to improved fuel economy, he says. Both common-rail fuel systems and – in Daimler’s case – amplified common-rail systems will be the fuel economy solutions for diesel engines for the foreseeable future.
“In many cases, Daimler and Detroit will continue to communize our platforms to ensure better quality and lower cost of ownership,” Williamson says. Daimler’s current DD15 increased fuel pressure from 32,000 to 38,000 psi, which allowed for better fuel economy and complete fuel atomization. “This results in a more complete combustion of the fuel being burned while also resulting in fewer exhaust emissions,” he says.
