International Truck unveiled a new fuel efficiency package for its ProStar model, called ProStar ES. Short for efficiency specification, the ES package combines enhanced aerodynamics with improved powertrain efficiency and Navistar’s proprietary OnCommand Connection remote diagnostics system.

"The ProStar ES is a package, an ecosystem, if you will, developed by our performance engineering team to deliver maximum fuel economy," says Jodi Presswood, vice president of the Navistar Heavy-duty Truck Product Line.

During an online webinar, Presswood outlined the features of the new ES package. They include a choice of the Maxxforce N13 engine coupled to an Eaton Fuller Advantage 10-speed automated transmission, or a Cummins ISX 15 mated to the same transmission in a package known as the Eaton Cummins SmartAdvantage powertrain.

The SmartAdvantage powertrain gives the ProStar ES downspeeding capability, allowing it to run 150-300 RPM slower at cruising speed vs. previous offerings.

The ES package also includes a choice of Dana Advantek 40 or Meritor's 14X high-efficiency 6x4 drive axles, or Meritor's FuelLite 6x2 drive axle, all riding on SmartWay certified tires.

"The ProStar ES delivers up to 11% better fuel economy as defined by our performance engineering team," Presswood says. "By combining the four elements in the ES spec -- superior aerodynamics, optimized drivetrain, the Performance Engineering Team and the OnCommand Connection system -- we have created a package that changes the landscape in the on-highway tractor market."

Erin Peterson, chief performance engineer for the ProStar ES, says the company did full-scale wind tunnel testing to validate the performance of the package in crosswind situations, which account for a larger portion of aero resistance, on average, than direct headwinds. Studies have shown that on average, anywhere in North America, trucks will encounter a 9- to 10-mph crosswind. So that's what Navistar tested for when developing ES package.

"The package was developed to be the most aerodynamic when it comes to the wind average drag coefficient." he says.

According to Peterson, performance of the ProStar ES and a competitive truck were quite similar in a direct headwind situation, but as the wind direction was moved around to the side of the vehicle in greater angles of yaw, there was a considerable separation in the vehicle's performance, he says.

"We were able to actually turn the full-scale truck inside the wind tunnel to demonstrate the effect of a 9-mph crosswind on a truck traveling at 65 mph. We found the higher the yaw angle, the better the performance," Peterson says.

ProStar ES includes a three year subscription to OnCommand Connection, Navistar’s predictive diagnostic system which includes a portal that monitors vehicle performance in real time to ensure maximum operating efficiency.

Customers also have the opportunity to meet with Navistar’s Performance Engineering Team to tailor the spec to individual drive cycles and applications.

“The ProStar ES is by far the highest quality and most fuel efficient package we’ve ever offered,” said John McKinney, Navistar senior vice president, Sales and Marketing. “Our Performance Engineering Team has studied, tested and validated hundreds of vehicle, powertrain and component combinations to develop an ‘optimized spec package’ that maximizes fuel efficiency and is easy to order.”

The webinar on Dec. 5 was the official introduction of the ES package that Navistar showed at the American Trucking Associations’ Management Conference & Exhibition in October.

Customers can begin ordering the ES package on Dec. 15.