The X15N™, an improved design thanks to customer feedback

X15 rendering

The trucking industry is moving towards cleaner, more efficient engines – and the Cummins X15N™ natural gas engine is a big step in that direction. This article explores the X15N’s new features and improvements that were developed based on customer feedback and experiences with the 12-liter ISX12N™, our first natural gas engine designed for use in class 8 trucks. The X15N embodies Cummins’ dedication to innovation and our dedication to customers and their feedback.

Performance improvements from the ISX12N

The ISX12N taught us a lot of lessons about how a natural gas engine needs to perform in the heavy-duty truck market. We carried those lessons and the customer feedback into the design and engineering of the X15N to make it a true heavy-duty option. The X15N was built specifically as a natural gas engine and leverages Cummins’ HELM™ platforms. Here are the highlights on some of the component improvements compared to the ISX12N:

  • An X15N natural gas-specific cylinder head allows for improved thermal distribution and improved spark plug life.
  • The sculpted block and compact design for the X15N results in reduced weight compared to the ISX12N.
  • The X15N turbocharger is now a dual-entry wastegate and has upgraded materials for improved durability and altitude performance.

With up to 500 hp and 1850 lb-ft of torque, the X15N has more low-end torque than the previous model. It has nearly 40% more engine braking power than the ISX12N, and additional braking horsepower is available with the fan on.

In terms of emissions, the X15N meets U.S. Environmental Protection Agency (EPA) and California Air Resources Board (CARB) regulations for 2024. This engine can also significantly reduce greenhouse gas emissions compared to diesel engines. Yet, the environmental benefits really shine when using renewable natural gas made with biogas that offers a carbon intensity that can be neutral or even below zero, depending on the energy source.

Lower total cost of ownership

One of the standout features of the X15N is its improved fuel economy, which is roughly 10% better than the ISX12N with a matching rating and similar duty cycle. This reduces operational costs, and, since less fuel is burned, combustion emissions are also reduced. The X15N has improved fuel control with a fuel injection system that consists of eight separate solenoids instead of the large single fuel control valve on the ISX12N.

The X15N aims to further reduce downtime by increasing the intervals between oil drains and improving spark plug life. This has been made possible by increasing the oil capacity, improving the power cylinder and managing oil oxidation to consequently bring down the rate of oil degradation. The X15N spark plugs have increased ceramic strength and electrode geometry and material, and when coupled with the reduced temperatures, improves its plug life.

All these improvements align with industry ions? to minimize environmental impact through decreased waste and encouraging a longer lifespan for essential engine components.

Improved durability

The X15N engine introduces several features aimed at improving durability and reliability, drawing on the lessons learned from the ISX12N.

One key change is the use of steel pistons, which are more resistant to wear and tear. This adjustment, paired with an integrated ignition and injector control systems, promises to offer more reliable operations and longer engine life.

Furthermore, the ignition system has moved from being a capacitive to an inductive system, which has extended the life of spark plugs. This transition minimizes the need to disconnect the engine harness when replacing spark plugs, reducing wear on terminals and preventing the ignition coil from heat exposure inside the adapter tube, ultimately increasing reliability.

Additional enhancements in the engine include modifications to the crankcase ventilation system motor alignment, the adoption of stainless steel upper and lower bearings with better sealing, and the use of larger bearings. These improvements mark a step forward in achieving a durable and reliable engine.

Fully optimized powertrain

The X15N offers a fully optimized powertrain that integrates the latest advancements in transmission and fuel delivery systems. Specifically, when paired with the Cummins Eaton Automated Transmission Technologies Endurant HD™ N Transmission, the engine operates with unmatched efficiency and performance. This synergy allows for smoother gear transitions, improving the overall driving experience and reducing wear and tear on the vehicle's systems.

Moreover, the incorporation of the Cummins Clean Fuel Technologies Fuel Delivery System provides industry-changing fuel systems designed with drivers and fleet operators in mind.

The Cummins X15N represents the new era of engine technology and is ready to power fleets to get the job done while reducing emissions. Contact your local Cummins sales office or preferred OEM today to learn more.

Puneet Singh Jhawar

Puneet Singh Jhawar

Puneet Singh Jhawar is the General Manager of the global natural gas business for Cummins Inc. In this role, he is responsible for the product vision, financial management and overall performance of the natural gas business. Over his 14-year career at Cummins, Jhawar has cultivated successful relationships with a number of Cummins’ largest customers. Jhawar has extensive global experience, with roles based in the Middle East, India, Europe and the US.

Cummins Custompaks are being used for water management as Thailand struggles with its water crisis

CustomPak on site

Water crisis

Sixty Cummins Inc. CustomPaks are in service in Thailand as part of a critical water management plan aimed at easing the country’s water crisis – a crisis that has caused enormous economic and social damage and stirred conflict among communities.

Over the past several decades, Thailand has continually faced water problems caused by severe drought. Water reserves in dams and reservoirs are insufficient while water resources are often contaminated with toxins caused by urban communities and the industrial and agricultural sectors.

Severe flooding is a threat, too, at a time when the realities of climate change are hanging over the country.

As a result, the allocation of precious water resources, which must be shared among various stakeholders including new and existing industry, large and small agriculture, and cities and villages has become a flashpoint.

Kittithanapat Engineering Co. (KTP), has been involved in the water management system since 1996, working closely with authorities such as the Royal Irrigation Department, Department of Water Resources, Bangkok Metropolitan Authority and others.

CustomPaks on site

600 hp CustomPaks

To help KTP meet its often urgent requirements, Cummins DKSH (Thailand) has recently supplied 60 Australian-built CustomPaks – 45 powered by Cummins’ X15 engine rated at 600 hp, and 15 powered by the QSL9 rated at 325 hp. These fully self-contained powerpacks are emissions certified to Tier 3.

The CustomPaks are coupled to hydraulically-driven, large-volume submersible water pumps sourced by KTP from US company Moving Water Industries (MWI); KTP is the exclusive distributor in Thailand for these MWI Hydroflo pumps.

Prior to Cummins’ involvement, KTP was using another diesel engine brand but service support wasn’t up to the standard required.

Long-serving KTP engineer Kittisak Thanasoot says Cummins DKSH’s reputation for technical and aftersales support along with the reliability of the Cummins product were a key reason behind KTP’s decision to specify the CustomPaks for the Royal Irrigation Department.

The ability of Cummins DKSH to respond to short delivery times was also important.

“Supplying large quantities of high horsepower diesel engines for emergency situations such as flash flooding can be a challenge for KTP,” says Kittisak Thanasoot.

“Responding to the needs of the government agencies to manage such problems in a timely manner and with least impact on communities, KTP has found the answer in our partnership with Cummins DKSH.”

Power, pride and passion

Parked semi truck

The switch back to Cummins power has been beneficial for iconic New Zealand company Uhlenberg Haulage. It's all about whole-of-life costs.

Uhlenberg Haulage is closing in on 60 years in business, having been founded in 1966 by Mike and Carol Uhlenberg.

Based in Eltham, Taranaki, in New Zealand’s North Island, the operation is today owned and operated by their sons Chris, Daryl and Tony Uhlenberg.

Describing the Uhlenbergs as “old school family truckies”, Daryl talks about the company’s time-honored journey with a definite tone of pride, especially the work of his parents in laying the foundations for what is today an iconic fleet in its own right.

Cummins Inc. made its debut in the Uhlenberg fleet in 1971 with an NH250 powering a second-hand Kenworth K923 used in logging. A second Kenworth, a new W924 with a Cummins NTC335, followed soon after hauling an LPG tanker.

The Uhlenberg operation today comprises 40 prime movers and a variety of trailing gear to cater for the myriad of a jobs the fleet is involved in.

A number of Peterbilts feature in the fleet although Kenworth is now the brand of choice with six new units to be delivered over the next 12 months to cater for business growth.

Cummins’ X15 Euro 5 engine rated at 550 or 600 hp is the preferred power specification, with 18 red engines currently in the fleet.

Uhlenberg family in front of truck

Whole-of-life support

“The switch to Cummins has been a very good experience for us. We have nothing but praise for the Cummins organization,” says Daryl.

“The whole-of-life picture is the key thing for us and we’ve got that nailed with the support we get from Cummins – parts availability, scheduled maintenance, life expectancy and in-frame rebuilds.

“So the red engines turn up, we run them to life, which is 900,000 to 1.2 million kilometers, and then Cummins does an in-frame overhaul in a timely manner. If there’s an issue, parts and support are close by.

“The support we get from Cummins Palmerston North is fantastic, second to none.”

Daryl recently looked under a Kenworth that was in the workshop for a service and was surprised to see no oil leaking from the one-million-kilometer X15. “I remember when I was a fitter we had to wear a raincoat when working under a truck,” he jokes.

Fuel agnostic

Acknowledging that the push to decarbonize is now “very real”, Daryl likes the idea of Cummins’ fuel agnostic concept where one base internal combustion engine, optimized to run on diesel, can also be customized to run on ultra-low and zero-carbon fuels like renewable natural gas and hydrogen.

“My father was a pioneer of linehaul trucking in New Zealand and he always embraced new technology. He was never scared of it,” he says.

“I tend to be a little more cautious but I can see where a 500 hp natural gas or hydrogen engine would work for us in short haul applications,” he admits. “We’re certainly willing to look closely at these alternative fuel technologies when suitable infrastructure is in place.”

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