Examining the X12

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Diesel’s State of the Union’ column is examining the X12 from Cummins, it is the North American version of the worldwide ISG platform, originally developed for Asian markets. For the North American markets it gets the emissions-related air-handling and after treatment, developed and evolved for the X15, though sized for the new engine’s nominal 12 litre displacement.


Examining the X12


Obvious technical highlights include the block design. Still in grey iron, it features metal only in areas of high stress so, for instance, ribs in the cylinder wall area provide a load path between the head-clamping bolts down to the main part of the crankcase and main bearing area with the far thinner in-between block walls providing more a means to keep the engine together.


Composite in-head cam cover and oil pan are semi-structural adding stiffness and offering noise reduction. The front accessory drive for the fan and air conditioning compressor is compact and features the coolant and oil pumps bolted to the side of the block, which allows Cummins to customise the configuration of water and oil connections to suit different OEM requirements without recasting major areas of the block.


The turbo charger (by Holset) is sized for the 12 litre as is the EGR cooler, but both bear heavily on the designs for the ISX/X15. So many of the issues that bedevilled earlier components have been addressed in this iteration. All the actuators in the X12 air-handling are identical to the X15’s so benefit from the experience and development of the bigger engines systems, said Cummins officials at the TRC launch site.


The X12 is capable of reaching 1700 lb-ft (2300 Nm) peak torque at 1000 rpm, which remains available to over 1400 rpm, reducing the need for gear shifting and giving better low-speed lugging on grades.


“During the design process for the X12, we evaluated every opportunity to reduce size and lower weight, but importantly, we achieved this with no compromise to structural strength, so that our next-generation 12-liter comes with all the durability associated with a Cummins Heavy-Duty engine,” says Jim Fier, Cummins Vice President Engineering, speaking at the X12 unveiling which took place at the TRC.


“We are really excited about how the next-generation X12 will complement our engine portfolio and provide to our OEM partners a compact yet capable engine, an ideal fit for shorter-nose conventional cabs, while very low weight makes the engine a great power solution for sleeper trucks sensitive to front axle weight.”


Customer-focused innovation resulted in a Single Cam In Head (SCIH) design with roller valve train and high-efficiency intake ports to minimise complexity. The latest version of Cummins VGT Turbocharger incorporates reliability and durability enhancements, to boost transient response, and combines with an integrated low-weight engine brake, to provide strong engine braking at lower rpm.


The next-generation X12 Series will be in full production in 2018, following the completion of an extensive field-test program.


  • Over-The-Air Connections


The X12 will be ready from the factory to take advantage of advanced solutions using Cummins Connected Calibrations family of applications in the US, which will empower fleets to improve productivity when connected to a capable telematics system without a visit to the service bay. With solutions using Cummins Connected Tuning applications, the X12 Series can be adjusted and optimised over the air, for improved costs of operation, without a trip to the service bay.


A significant contribution to improving truck uptime is realised with Connected Diagnostics, enabled through the engine’s Electronic Control Module (ECM) and the telematics system. Connected Diagnostics automatically processes fault code data, sending instant notifications from Cummins detailing probable cause, and providing recommended actions. The expert advice delivered by email, app or web portal enables the fleet manager to make informed decisions about continuing truck operations and when to schedule a service visit for the most convenient time, maximising uptime.



Read a full report on the new engines Cummins are releasing in North America, in the next issue of Diesel.