Truck & Off-Highway Engineering - October 2024 - 16

Detailing
the
2027
CUMMINS
X15
The next-gen
15-liter diesel engine
meets all 2027 EPA
emissions regulations
while boosting fuel
efficiency.
by Matt Wolfe
C
ummins provided extensive details of the design and engineering
efforts involved in developing the new HELM version
of its X15 diesel engine. The company says its new engine will
offer up to a 7% improvement in fuel economy compared to
the current EPA 2024-certified X15 while also meeting all 2027
emissions targets. Truck & Off-Highway Engineering was invited to
tour the company's headquarters in Columbus, Indiana, where journalists
were given a comprehensive update on the hardware powering
the latest X15.
The current crop
Cummins' present stable of EPA24-compliant X15 engines carried
over largely the same specs as the 2021 variants. The 2024 X15
comes in three flavors depending on the application.
The Efficiency Series leads off the range with an output of 400500
hp (298-373 kW) and a torque range of 1,450-1,850 lb-ft (1,9652,508
Nm). The Performance Series is the middle child with a power
rating of 525-565 hp (391-421 kW) and 1,650-2,050 lb-ft (2,2372,779
Nm) of torque. Topping the range is the Productivity Series,
which ranges from 430-605 hp (320-451 kW) and 1,650-2,050 lb-ft
(2,237-2,779 Nm).
All three variants feature a variable geometry turbocharger (VGT)
that reportedly offers higher boost pressures at lower engine speeds.
Cummins states that the 7th generation VGT provides 5% higher turbocharger
efficiency through new wheel options and a multi-clearance
shroud. The current-generation VGT also features a patented
sliding nozzle ring.
16 October 2024
The new HELM version of Cummins' X15 diesel
engine will offer up to a 7% improvement in
fuel economy compared to the current EPA
2024-certified X15.
Evolution of engineering
Cummins representatives gave a comprehensive presentation
on many of the design details of the new
2027 X15 including updates to the cooling system, fuel
system, piston design and serviceability changes. " The
X15 first went into production in 1998 and now has
been revised a total of nine times to match the different
emissions regulations, " said Tom Marsh, program
leader at Cummins.
" If you look all the way back to when we initially
developed the X15 and imagine the technology level in
terms of computing power, it was very much hand calculations
and, in some cases, still drawing boards. We
really didn't have the capability we have now in terms
of computational fluid dynamics and all of our finiteelement
process tools, " Marsh explained.
" What you'll see is that we've carried over a lot of
the fundamental architecture that we had in previous
generation X15s, " Marsh said. " We've taken all of the
existing technology and developed it with the new
global HELM platform that allows us to engineer smaller,
lighter and more efficient engines. "
The block is one area where Cummins leveraged the
latest design tools and capabilities. " If you compare
the old block to the latest one, it's about three inches
shorter than the existing engine, " Marsh said. " We've
also done a lot of work on the structural analysis and
TRUCK & OFF-HIGHWAY ENGINEERING
CUMMINS
Truck & Off-Highway Engineering - October 2024

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