Project Description


The X15 is an evolutionary development of the ISXe5, the backbone of many successful trucking operations in Australia and New Zealand.

The X15 uses the same proven hardware and emissions reduction technology – Selective Catalytic Reduction (SCR) – as the ISXe5 and incorporates all the improvements in reliability, fuel economy, maintenance intervals and total cost of ownership that have made the ISXe5 a stand-out in the heavy-duty market.

As the only diesel engine manufacturer with in-house integration of all critical subsystems from air handling to exhaust aftertreatment, Cummins is able to optimise the combustion process and provide that critical edge in fuel economy.

The XPI (Extreme Pressure Injection) common rail fuel system operates independently of engine speed, providing precise injection and combustion control at injection pressures greater than 30,000 psi. Multiple injection events per cycle improve fuel efficiency and enable smoother operation.

All X15 engines include the Cummins Intebrake, providing the strong engine brake retardation for which the 15-litre Cummins is renowned. All X15 ratings 485 hp and above feature best-in-class peak retardation of 600 hp.

The proven SCR exhaust aftertreatment on the X15 is a fully integrated system developed by Cummins Emissions Solutions. Importantly, it’s a well-founded claim that Cummins SCR uses less AdBlue/DEF than competitor products.


The X15 features ADEPT technology – a suite of advanced electronic features capable of delivering fuel economy gains through improved powertrain integration.

ADEPT – Advanced Dynamic Efficient Powertrain Technology – is for use with Eaton’s 18-speed automated UltraShift Plus transmission. It utilises load, speed and grade-sensing technology to initiate adjustments to engine power, torque and transmission gear selection to take advantage of vehicle momentum for better fuel economy.

The first ADEPT package includes two features: SmartCoast and SmartTorque.

SmartCoast operates when the vehicle is on a moderate downhill grade by disengaging the front box of the transmission and returning the engine to idle to reduce drag, maintain momentum, and ultimately improve fuel economy. Once the engine commands the transmission to be put back in gear, the appropriate gear is engaged.

SmartTorque uses torque management intelligence to help eliminate unnecessary downshifts and keep the engine operating in the most fuel efficient ‘sweet spot’. Torque is varied across all gears depending on torque requirement.

For Australian operating conditions, the torque varies up to 1850 lb ft or 2050 lb ft depending on the horsepower and peak torque rating of the engine.


Downloadable information

X15 Brochure