Caterpillar Unveils New C13D Off-Highway Engine Platform

Cat has launched a new 13-liter engine designed to offer increased power and fuel efficiency, while consolidating its engine lineup to suit a range of applications on a single architecture.

Caterpillar has launched its new off-highway 13-liter diesel engine platform, the C13D, at CONEXPO 2023 in Las Vegas. Cat states that the C13D was “purpose-built for rugged, long-lasting performance in off-highway applications” and that the new engine was designed to realize increased power density, torque and fuel efficiency.

Mark Stratton stressed that Caterpillar is dedicated to diesel during the reveal of the new C13D engine. (SAE/Ryan Gehm)

“Off-highway OEMs and equipment owners face a rapidly evolving business environment that demands improved worksite productivity and reduced operating costs while addressing increasingly stringent emissions standards,” said Steve Ferguson, senior vice president Caterpillar Industrial Power Systems. “Internal-combustion engines are the prevailing workhorses on most jobsites around the world, which is why we’ve invested in the next-generation Cat C13D diesel engine platform to address their challenges.”

New and improved

Caterpillar 13D engine. (Caterpillar)

The C13D is an inline, six-cylinder turbocharged design that will be offered in eight power ratings ranging from 456 to 690 hp (340 to 515 kW) with a peak torque rating of 3,200 Nm (2,360 lb-ft). Cat states that all power ratings will be available with no alterations to the C13D’s core architecture. The C13D also will meet emissions standards for all markets, such as EU Stage V, U.S. EPA Tier 4 Final, China Non-road IV, Korea Stage V and Japan 2014. C13D models also will be available for less regulated markets, according to Cat.

The company’s philosophy for developing the C13D platform was to supply comparable power and torque to what its current 13-, 15- and single-turbo 18-liter engine platforms offer. By providing a range of power outputs within a single engine platform, Cat believes that it can consolidate design, assembly and supply-chain requirements across multiple applications.

“It’s a similar footprint to our current 13-liter, and it’s obviously smaller than our 15- and 18-liter [engines],” said Mark Stratton, VP and general manager of Caterpillar’s large industrial engines business. “It comes in at just 2,500 lbs. (1,134 kg). So, we’ve taken weight out of it but added strength and durability.”

Stratton said that the C13D offers up to a 20% increase in total power and as much as 25% more low-speed torque compared to the previous-generation engine. Cat also designed the C13D for use at altitudes of up to 12,000 ft. (3,658 m), which is reportedly double the elevation as for legacy Cat engines. The C13D was tested and certified for use in ambient temperatures as hot as 140 deg F (60 deg C) and as cold as -40 deg F (-40 deg C).

“We’re just announcing this engine [at CONEXPO], but we’ve got something north of 6,000 lab hours on this engine already,” Stratton said. “It’s meeting all the performance targets, so when I tell you what this engine is going to do, I’m not just guessing. The teams are proving it every day in our labs in Mossville, Illinois, and around the world.”

“This is the first engine in this size range that we’ve done completely digitally,” Stratton continued. “Before we ever made the first part, before we ever turned the first bit of diesel fuel, before we ever put this engine in a lab, we had extensive testing and validation in the virtual world. We literally can run thousands of different piston-ring liner simulations over night with our capability.”

Engineering explained

Specs sheet for the Caterpillar 13D engine. (Caterpillar)

Engineering improvements compared to the outgoing 13-liter engine include the modularization and elimination of components in anticipation of configuration adjustments required for future tiers of emission standards in the U.S. and EU. Caterpillar states that this design consideration permitted the omission of these components without relocating customer connection points.

The company also claims a reduction in the number of leak joints by more than 45% and that the C13D’s lower fluid consumption allows for extended service intervals up to 1,000 hours for some applications. The C13D can operate on renewable liquid fuels such as 100% HVO (hydrotreated vegetable oil), B100 distilled biodiesel and B100 standard biodiesel. Additionally, the engine’s architecture is designed for adaptation of natural gas and hydrogen fuel systems.

“The core architecture – the block, pistons, connecting rods, crankshafts and even how we sculpt the cylinder heads – when we were designing it for diesel, we had full intention to be able to convert it into a hydrogen and a natural-gas application in the future,” Allen Chen, product marketing manager for the C13D engine, Industrial Power Systems division, told SAE Media following the engine’s reveal. “That’s why we’re saying it’s future-protected, for those alternative gaseous fuels, for spark ignition. This is our launching platform; it’s not going to burn it right now, but when customers want it and they’re ready for it, we’ll be ready for them.”

Additional improvements for the C13D include a new rear gear train, stiffer core architecture and a common-rail fuel system that reduces noise by a claimed 3 dB compared with the C13D’s predecessors. Engine-mounted aftertreatment and cooling packs also will be available from the factory to reduce installation and validation costs, Stratton said.

Caterpillar 13D engine. (Caterpillar)

“How come it takes so long to design, for example, a cylinder head?” Stratton said when discussing the subtleties involved in designing a single component. “We analyze the harmonics over and over again of the block, of the gear train, of the head, of all the components to try to reduce the vibration that creates noise and harshness and the sounds that your customers hear every day. We only do this [all-new engine design] once every 30 years, so we’re going to do it right.”

Coming soon

The C13D currently is going into machine applications for validation in the dirt, according to Chen, who said he’s been working on this development program for six years. Three customers in the U.S. have been selected for the durability testing phase. “They were specifically targeted and partnered with because they will put this engine through the paces,” he said.

The engine will be available for early OEM pilots in 2025 and is scheduled for production in 2026. According to Cat, the new engine is intended for applications such as rock crushers, trenchers, agriculture machines, material-handling equipment and large industrial pumps.

“We get questions about ‘why might you be building a diesel engine today?’” Stratton said. “First and foremost, we are one-hundred percent committed to the diesel platform for the future because we know our customers are going to need it. If you need a diesel engine, if that’s the right answer, we want the best one on the market.”