BTS 2023

Cummins lifts the lid on its new big bore engine

Cummins unveiled its most advanced ever big bore diesel truck engine at the Brisbane Truck Show.

The entirely new 15-litre platform, known as the X15D, will deliver the highest-ever outputs for a Cummins truck engine while setting new standards for fuel efficiency at ultra-low emissions levels.

“With the all-new X-series platform, Cummins is taking the internal combustion engine to a next generation level, capable of meeting future ultra-low emission standards with a low-to-zero carbon fuel capability,” said Mike Fowler, director of on-highway business for Cummins Asia Pacific. There is no set date for release of the X15D in Australia and New Zealand. An extensive field test program which started in Australia in 2021 will determine when this will occur.

“The X15D will only be released when we are completely satisfied with its reliability and durability in meeting the harsh demands of the Australian B-double duty cycle,” said Fowler.

A key feature of the X15D is its dry weight reduction of 225kg compared with the current X15. A sculpted iron block and composite oil pan are among the weight-saving features that result in the X15D having the highest power-to-weight density in the industry.

“The unique power cylinder design enables much higher peak cylinder pressures – 20 per cent higher than the current engine – and that enhances power density and overall efficiency,” Fowler added. Featuring the latest evolution of Cummins’ XPI (Extreme Pressure Injection) fuel system, the X15D will be offered with ratings up to 660 horsepower backed up by massive peak torque of 2360 lb ft. The highest rating eclipses the current X15 peaks of 615 horsepower/2050 lb ft and will enhance Cummins’ engine down-speeding strategy for improved fuel economy.

“This strategy is about reducing cruise rpm for fuel economy gains while at the same time providing the grunt to meet both driver and trip time expectations,” said Fowler, noting that peak torque extends over a wide band, from 1500 rpm all the way back to 1000 rpm.

He notes field trials of the X15D rated at 660 horsepower in Australia have shown fuel economy improvements up to eight per cent. By the end of 2023, more than 10 trucks will be involved in the field trial and the aim is to accumulate more than five million test kilometres.

For more information, call 03 9765 3222 or visit

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