Cummins unveils new 15 liter big-bore diesel engine

9 June 2023

Cummins unveiled its new big-bore diesel truck engine at the Brisbane Truck Show in Australia. The entirely new 15-liter platform, known as the X15D, will deliver the highest-ever outputs for a Cummins truck engine, along with improved fuel efficiency at low emissions.

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. 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, with the aim to accumulate more than five million test kilometers.

The X15D will be offered only as a Euro VI engine, Cummins said. In Australia, Euro VI (Stage C) emission requirements will be phased-in for newly approved heavy vehicle models from November 2024 and for existing models from November 2025.

Featuring the latest evolution of Cummins XPI (Extreme Pressure Injection) fuel system, the X15D will be offered with ratings up to 660 hp and a peak torque of 2360 lb-ft that extends from 1500 rpm down to 1000 rpm. The high power and torque rating eclipses the current X15 peaks of 615 hp/2050 lb-ft and will enhance Cummins engine downspeeding strategy for improved fuel economy.

A key feature of the X15D is its dry weight reduction of 225 kg 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, Cummins said.

Power density and overall efficiency are further enhanced by a new power cylinder design that enables 20% higher peak cylinder pressures than the current engine.

The X15D is a key part of Cummins ‘fuel agnostic’ platform, which comprises diesel, natural gas, and hydrogen internal combustion engines derived from a common base with high parts commonality.

Source: Big Rigs Australia | Cummins