Shell Starship 2.0 propels fuel efficiency to greater heights

When Shell Lubricant Solutions launched its first Starship tractor-trailer in 2018 to showcase all the available components and lubricants a truck can employ to become “hyper-fuel efficient,” the team knew with a little more time, they could make it even better. As is, the Class 8 truck with a bullet train husk achieved a freight-ton efficiency of 178.4 ton-miles per gallon, 2.48 times better than the North American average.

“Actually, there was lots of stuff left on the table,” recalled Robert Mainwaring, Shell Lubricants’ technology manager for innovation. “The hurry that we had to make with Starship to get it on display meant some things were unfinished—and those things had a lot of promise.”

Mainwaring said that promise is now fully realized with the revelation of the Shell Starship 2.0 tractor-trailer, appearing publicly for the first time at the ACT Expo in Long Beach California. And the Shell team has had plenty of time to prepare.

“Rather, ironically, because of COVID, we've had a whole year to refine all of those things, so whatever we ended up with now is quite genuinely the best thing we can be with the given reasonable time and available technologies,” he said.

Ryan Manthiri, Starship 2.0 project leader, said the foundations for the new truck revolved around “reducing opposing forces, improving the driveline and powertrain efficiency, and encouraging a steady driving style.”

The carbon fiber body remained mostly unchanged, with the exception of changing the grille system and the addition of Truck Labs TruckWings automatic gap closure device, which activates at highway speeds. Durable side skirts and custom boat tails on the trailer continue to smoothly direct air and slice through the wind. On top of the trailer, a 5,000-w array of solar panels generate additional power to the 12-v main battery bank and hydraulic landing gear battery pack.

The chassis was swapped from a lighter-weight 2015 International ProStar to a 2021 LT. The 6x2 configuration also reduces weight and friction. Manthiri noted that a differential adds 300 lb., and because a 6x4 has two, that weight is now stripped off.

Under the hood, the most notable difference is the 2020 Cummins X15 (EX Efficiency Series; 400-hp; 1,850 ft.-lbs. torque) mated to the Eaton Cummins Endurant 12-speed transmission. The original was a 2015 prototype engine.

The newer version launched in late 2019 featured tweaks to the water pump speed to reduce parasitic losses and better air handling in the turbocharger for example. Overall, this Eaton Cummins powertrain improved fuel efficiency by 5% over the previous version.

On the road, the powertrain offers GPS-enabled functions to help drivers remain in the optimal gear ascending hills through predictive gear-shifting.

“The sync between the engine and the gearbox is much, much tighter than it was before,” Mainwaring said.

Low rolling resistant tires have also made incremental improvements that Shell has exploited, this time around choosing Michelin’s X Line Energy Z tires (steer) and X ONE Line Energy D tires (drive) on the truck, and Michelin X One Line Energy T tires on the trailer.

“The tires were basically chosen not only for their low rolling resistance but to reduce the overall weight and because of the high durability of these tires,” Manthiri said. “They’re Load H range tires, so they're set up to actually take the increased capacity because we're trying to maximize the potential on Starship. The axles have to be able to take the increased weight, and in order to put that down the ties have to be able to carry that load.”

Mainwaring also noted the new harnessing system allows the electronics systems to “all work in concert” as well.

And with lower viscosity, more fuel efficiency gains may be possible.

Of course, these components are all external to Shell Lubricants’ actual business. The company has also included five of its lubricant products to improve efficiency and reduce friction and wear. These include:

• Shell Rotella T6 Ultra 5W-30 (FA-4) engine oil: an oil featuring “a low high-temperature, high-shear viscosity formulation for reduced fuel consumption.
• Spirax S6 GXME 75W-80 transmission fluid: a fully synthetic fuel-efficient, long-life gear oil designed to enhance the performance and protection of current and future heavy-duty gearboxes
• Spirax S6 GME 40 wheel hub oil: a synthetic lubricant that offers extended drain intervals in heavy-duty commercial vehicle transmissions, which also protects higher torque transmissions coupled with increased horsepower engines.
• Shell Rotella ELC Coolant: an extended life coolant/antifreeze free of silicates and phosphates with a concentrated formula for better performance
• Shell Gadus S5 V220 2 chassis grease: advanced performance grease with additives that prevent wear, oxidation, and corrosion.

The Rotella T6 is not commercially available yet, nor do OEMs recommend 5W-30 in their engines, but as Karin Haumann, OEM technical manager with Shell Global Solutions, asserted, Shell is "pushing the envelope so that we can show that it's possible."

“The thinner the oil, the easier it is to flow, the less input energy it takes for parts to move against each other,"  Haumann explained. "The increased fuel economy comes from that.”

At the time of the interview, Mainwaring could not disclose how much these changes have improved Starship’s freight-ton efficiency but believes the changes in technology over the past three years will yield substantial gains.

“If we went from 2.5 times, as we were, to 3 times the American average, that'd be fantastic,” he surmised.

The freight-ton equation

So what exactly is freight-ton efficiency? According to the North American Council for Freight Efficiency, it’s a more accurate way than mpg to gauge how effective a truck is at hauling a load. This is calculated by dividing total miles driven by gallons of fuel expended, which you would do to get mpg, and then multiplying by tons of payload.

“The objective of the truck is to carry goods, so you want a metric which leverage is energy efficiency for transporting goods, and it turns out that freight ton efficiency is that.

“You want to maximize that ratio, and when you've done that, you've done the very best you can to freight transport,” Mainwaring said.

The very best technically is an FTE of 610, but that would be if all the weight was just cargo.

“Roughly said, 50% of the full truck’s weight is the truck itself, and that leads you down to having a ceiling value of about 305 ton miles per gallon,” he said. “What you're trying to do is edge the freight ton efficiency upwards towards that 305—you'll never actually get there, but what's the best you can be?

“The plates of that,” he continued, “are the mass of cargo, the mass of the truck, the rolling resistance of the tires, the aerodynamics, and then the tank-to-wheels efficiency of the driveline. And if you optimize all of those, you'll then be as close as you can beat that value of 305.”

The route to greater efficiency

Starship 2.0 ran the same route from San Diego to Jacksonville, Florida, as “an apples-to-apples comparison” with the earlier iteration, said Jeff Priborsky, global marketing manager for the on-highway fleet sector at Shell Lubricants. Shell increased the payload by 18% to 47,100 lb., versus 39,900 lb. in 2018. The cargo remained the same: artificial coral reef.

A shorter 400-mile route with less payload was also run this summer in North Carolina to demonstrate shorter hub-and-spoke duty cycles, which are becoming more common, Priborsky said.

And Shell, which has its own corporate ambition for carbon neutrality by 2050, intends for this project to inspire fleets across the continent to understand the benefits of these fuel-efficient additions, whether used in combination or individually.

“What could happen if every fleet could take one or two, or three or more of the concepts that are shown on Starship and apply them to their own fleet?” Priborsky asked. “Those fleets that aren't using fuel-efficient tires, or low-viscosity lubricants, what if they did something around the air gap closers, or put on those boat tails? They can all those things do to be more efficient.”

And even if lowering emissions isn’t a major driver for a fleet, You know, and in essence, Priborsky added these additions can also carry financial benefits “because they're going to be lowering fuel costs as well, which we all know is one of their major costs.”

This article originally appeared on Fleet Maintenance.