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Perkins says it reduced the number of leak joints by 45%. (Perkins)

Perkins bets big on smaller engine for off-highway machines

The new 2600 Series 13-liter engine will do more with less thanks to variable geometry turbocharging.

Perkins Powertrain announced its all-new engine series for off-highway applications, launching the 2600 Series 13-liter engine at a press event in London where SAE Media was in attendance. Perkins states that the 2600 Series is intended for a wide array of off-highway applications including agricultural tractors, materials handling, construction, mining, aircraft ground support and other use cases.

“As the off-highway industry advances toward a lower-carbon future, equipment manufacturers still face expectations for long-term productivity and reliability in the world’s most-demanding work environments,” said Jaz Gill, vice president of global sales, marketing, service and parts. “The new Perkins 2600 Series engine platform demonstrates how we’re leveraging our experience, intelligence and commitment to help OEMs navigate the energy transition with power solutions that deliver exceptional performance on the worksite.”

During the launch event, Perkins discussed several key details of the 2600 Series, including complete specs for all versions as well as overall design goals. Company representatives also confirmed that the 2600 Series will replace not only the current 13-liter offering, but also the larger 15- and 18-liter engines in their range.

Just the facts
The 2600 Series is an inline-six single overhead cam (SOHC) architecture displacing 12.9 liters (787.2 cubic inches) with a bore and stroke of 130 x 162 mm (5.1 x 6.4 inches). Max output is rated at 690 hp (515 kW) and peak torque is a stout 2,360 lb-ft (3,200 Nm) at 1,300 rpm. There will be a total of eight power ratings ranging from 456 hp (340 kW) to 690 hp depending on the tier of emissions regulation for the customer’s market. These power levels are all available across a common core engine.

Currently there are two variants of the 2600 Series: the 2606J-E13TA and the 2606EA-E13TA. The 2606J is the EU Stage V / U.S. EPA Tier 4 Final / Japan 2014 / Korea Stage V compliant version. The 2606EA variant is specifically rated for China Nonroad Stage IV emissions. All 2600 Series variants utilize a common rail direct-injection fuel system and a variable vane geometry turbocharger.

Perkins states that the integration of several key components as well as a reduction in the number of leak joints by 45% has resulted in decreased fluid consumption and extended oil and fuel filter service intervals of up to 1,000 hours. Service and maintenance also has been simplified thanks to design features such as hydraulic lash adjusters (HLA), service-free open crankcase ventilation (OCV) filtration, the removal of all loose washers and a 5,000 hour-rated diesel particulate filter (DPF).

NVH also has been reduced compared to the outgoing design, thanks to a combination of a new rear gear train, stiffer core architecture, and the design of the common rail fuel system. Perkins states a total noise reduction of up to 3 dB when compared with its current 13-, 15- and single-turbo 18-liter engines. Fuel consumption has been improved to a claimed 40 kW/L (53.5 hp/L), at 0.45 kW/kg (0.27 hp/lb).

The 2600 Series engines are all compatible with renewable liquid fuels such as 100% hydrotreated vegetable oils (HVO), B100 distilled biodiesel, and up to B100 fatty acid methyl ester (FAME) standard biodiesel. The core architecture of the 2600 also reportedly supports the future development of spark-ignited natural-gas and hydrogen fuel capabilities.

Integrated ingenuity
One of the main design goals for the 2600 Series was simplification and integration of various subassemblies to improve reliability, serviceability and ease of implementation by end users. Perkins stated that “by modularizing and eliminating components, the architecture is space-protected to accommodate configuration adjustments anticipated for future tiers of emission standards in the U.S. and EU without relocating customer connection points.”

Following the presentation at the launch event, SAE Media interviewed Allen Chen, product marketing manager, to discuss the details of how Perkins accomplished those goals. Chen discussed several design details of the 2600 Series in depth, such as the integrated fluids module that houses critical components of both the cooling and oil system.

“We started by asking what functions we need the fluids module to accomplish? You need an oil filter, an oil thermostat to regulate the oil temperatures, a coolant thermostat, and you still need something pumping all the water around,” Chen said. “We looked at the components we previously used to convey coolant and oil and the total was in excess of 30 jumpers, castings, bonnets and pipes. All of that has now been condensed into a single fluids module.”

Chen continued, “We started off with the basics, so instead of having an oil cooler that’s on the outside, we tucked the oil cooler straight into the block. The water is already available, and it’s already circulating in the block and the head, so all it really needs to do is wash over the plates to cool your oil. This completely eliminated multiple leakage joints.”

“You also don’t see a thermostat housing or any external port for one on this engine,” he said. “We tailored the architecture so that the inlets and the outlets were both integrated into the block. The coolant thermostat is accessed and serviceable through an external panel and there is no inlet or outlet hose.”

Service simplified
Chen also discussed the design considerations that were made to improve ease of service for the 2600 Series, such as the cartridge-style oil filter instead of a spin-on cannister. “Spin-on filters are very reliable and very good tech, but are a bit of a mess and can often bond themselves to the mounting surface,” Chen said.

The cartridge filter on the 2600 Series is mounted inverted to make it more service friendly. “When you remove the cap, there is a metal tube inside that opens up a passage and the passage lets all the hot oil drain back into the oil pan. Passages are cast inside the block,” Chen explained.

The valvetrain also has seen serviceability improvements thanks to the use of hydraulic lash adjusters over solid lifters. HLAs are becoming more common on off-highway engines as their design eliminates checking valve clearance as a service procedure. AGCO also utilized HLAs in its CORE 75 off-highway engine that was displayed at CONEXPO 2023

Chen described the thought process behind the switch to HLAs. “Oil is readily available and easily plumbed, especially in these valvetrain components,” he explained. “So it made the most sense certification-wise. Also, by eliminating lash adjustment, we also gained a serviceability advantage. The valve cover is really annoying to pull off in a lot of these machines, and checking valve clearance once it is off isn’t easy either.”

The oil capacity of the 2600 Series also enables longer service intervals. The largest pan offered is 64 liters (68 quarts) and is rated for a 1,000-hour oil top-off interval. There is also a 45-liter (48-quart) pan with options for front and rear sumps as well as a shallow sump for applications with clearance constraints.

A design feature aimed at ease of user integration is the block-mounted engine control module (ECM). The unit is double ISO mounted on the side of the engine. Despite the amount of shock load and dust the unit may be exposed to in that location, Chen explained that this mounting offers several advantages. “It’s well damped from vibration thanks to where it’s mounted on the block. We’ve had success in the past with examples that have survived in this location with no issues, and this will be no different.”

Chen also pointed out the integration advantages of this mounting location. “What you don’t see on this pre-prototype engine is our jumper system with multiple pin connectors that would all spit out right here,” he said, pointing to the connector side of the ECM. “So depending on the customer, we would integrate things like telematics here. And for those that don’t have the aftertreatment system, it would be the same routing with a couple of components removed.”

Advanced geometry
A unique component of the 2600 Series is its variable geometry turbo. While this tech isn’t new, its implementation in an off-highway application as a way of supplanting larger powertrain offerings is a distinct approach as Perkins replaces its larger 15- and 18-liter offerings with this 13-liter engine.

“Since a variable turbo regulates the incoming air, you’re able to have a wide range of performance from a single engine,” Chen explained. “It was one of the reasons we were able to commonize iron sets. So customer value really was one of the biggest reasons we selected a variable geometry turbo. Variable turbos have been done before, perhaps not in this size range, but they have been proven to work.”

Chen continued, “Some of the challenges that we’ve seen, especially in harsher off-highway applications, is that these engines tend to cycle a lot. So that’s something that we were really paying attention to and testing to determine the turbo’s durability. We did a lot of experimenting with the actuator to try and minimize the number of cycles that the turbocharger will have to go through even with the transient nature of an off-highway engine.”

Perkins worked with an external supplier to size the turbo properly to ensure that the vanes vary their pitch as little as possible. “We selected the largest size we would need, and then scaled it down,” Chen said. “Response on an engine like this is not a large concern, and there’s no wastegate. There is a bypass valve, but all boost control is managed by the vanes.”

At launch, the turbo will be high-pressure oil cooled only. “There might be instances where water cooling is needed, but it is not currently a feature of the turbo system,” Chen said.

Coming soon
While an exact timeline was not revealed at the launch event, Perkins stated that the 2600 Series will be available for early OEM pilots starting in 2025, with commercial production scheduled to begin in 2026 at the company’s plant in Seguin, Texas. There are currently several prototype engines already in the field with select OEMs in key markets.

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