Shell explores new frontiers in fuel economy with Starship 2.0

Shell is returning with a new and improved Starship in its decidedly terrestrial goal of inspiring fuel-efficient trucks. The Starship 2.0 demonstration vehicle admittedly looks much like its predecessor, and the bullet-shaped design does share the same carbon fiber cab. But changes to the underlying vehicle run more than skin deep.

“This is a brand new truck,” says Jeff Priborsky, global marketing manager – on-highway fleet sector, noting how the latest model carries a 47,100-lb. payload compared to the 39,900 lb. hauled by the first Starship in 2018.

While it shares the bullet-shaped carbon fiber cab used by its predecessor, there is plenty of new content in Starship 2.0. (Photo: Shell)

Focusing on ton-miles per gallon

The goals remain the same – to inspire discussions about fuel-efficient gains that are possible today, and to take discussions about fuel economy beyond miles per gallon. Ton-miles per gallon better reflect the amount of energy used to move a given load of cargo, explains Starship project manager Ryan Manthiri. There’s an important distinction between the two measures.

On the surface, a truck that achieves 10 mpg seems to be more fuel efficient than one that comes in at 7 mpg. But the efficiency-related benefits are flipped on their head if the 10 mpg truck carries just one ton of freight while the 7 mpg truck carries 20 tons. “We looked to design and maximize on that specific metric,” Manthiri says.

The full results of the demonstration will be revealed later this month during ACT Expo. But Shell confirms Starship 2.0 outperformed its predecessor on a 2,200-mile test run from Florida to California. The first Starship achieved 178.4 ton-miles per gallon on that journey – 248% better than the North American average of 72 ton-miles per gallon.

That was largely achieved by shedding every possible pound from the truck itself, maximizing the payload within a gross vehicle weight of 79,500 lb.

Shell explores new frontiers in fuel economy with Starship 2.0Starship 2.0’s tractor-trailer gap is automatically sealed above 55 mph. (Photo: Shell)

Commercially available components

Look beyond the space-age carbon fiber cab and most of the underlying components can already be purchased. Starship 2.0 has been built on a 2021 International LT chassis featuring a 2020 Cummins X15 400 EX Efficiency Series engine paired with an Eaton Endurant 12-speed overdrive transmission. Weight reductions were realized by opting for Meritor’s Fuelite+ 6×2 drive axles, Michelin X Line Energy Z tires with a load range H on the drive axles, and Michelin X One Line Energy tires behind that.

Given Shell’s involvement, special attention has also been given to the lubricants. The engine oil is a Shell Rotella T6 Ultra 5W30 FA4, while other fluids include Shell Rotella NF extended life coolant, a Shell Spirax S6 GME 40 75W80 gear oil, and Shell Gadus 55 V220 2 chassis grease. But some of the most prominent changes are seen in the aerodynamics.

Shell managed to achieve a drag coefficient of 0.25, compared to the 0.6 achieved with an average tractor-trailer, Manthri says. By way of comparison, an aircraft will have a CD that measures around 0.02. The gap between the tractor and trailer is sealed at highway speeds using an automated fairing from Truck Labs.

That enhances further gains seen with a custom-fitted boat tail to eliminate low-pressure zones at the rear of the trailer, and updated side skirts to handle the air flows underneath. “You have this kind of almost fish though water kind of effect,” Manthri says of the end result. It even seemed to shed water differently when traveling through the rain. “These small things add up on a long journey.”

Even the staircase to the cab was customized, ensuring that the engine’s aftertreatment system wouldn’t need to be moved like it was with the first Starship. Manthri describes the Zeus air stairs like the opening of an aircraft door.

Shell explores new frontiers in fuel economy with Starship 2.0Solar panels on the roof of the trailer are designed to reduce the parasitic losses associated with the alternator. (Photo: Shell)

On top of the trailer roof is a five-string 5,000-watt solar array, with four of the strings feeding the main 12-volt battery bank and reducing the engine loading linked to the alternator, and one string dedicated to the hydraulic landing gear. “There’s a lot of internal features in this truck that have been geared toward operational efficiency,” he adds, referring to several advanced driver assistance systems.

Screens in the cab display the images from Stoneridge camera systems that have replaced traditional west coast mirrors in the name of aerodynamics.

Maximizing limits

“We’re going quite heavy. We’re maxed out on the gross vehicle limit,” Manthri says, referring to the payload of material destined to become an artificial reef. And that was the point.

There were some differences in the test runs themselves. Starship averaged 55-60 mph, but Starship 2.0 was allowed to creep up to 62 mph. “That’s a little bit more relative to what longhaul is doing today,” Priborsky says. Another 400-mile route was also run with a lighter payload to offer results that might better compare to today’s typical operations.

Even if run with a typical 34,880-lb payload and a gross vehicle weight of 65,000 lb., the technologies still make sense, Manthri says. Admittedly, regulators don’t tend to consider freight-ton efficiency when setting emissions standards, such as the CO2 limits that focus specifically on the amount of fuel a truck burns. But there is no denying the benefits of burning less fuel wherever possible.

“What if every fleet out there can see Starship and take one, or two, or three of the technologies that’s proper for their fleet and their operation?” Priborsky asks.