ProStar® models feature the new Cummins X15 engine, an evolution of the company’s proven and hugely successful ISXe5 power plant of which more than 6000 have gone into service in Australia since 2013.
International worked closely with Cummins South Pacific to install and calibrate the engine into the Australian ProStar® chassis, with much of the engineering undertaken at Cummins' pilot center in Melbourne.
The two companies also worked closely on the vehicle’s cooling package to meet very stringent requirements for cooling system efficiency and overall technology integration that will see the trucks thrive in Australia’s demanding operating conditions.
Power with efficiency
The big bore 15 litre engine is rated at a hefty 550 horsepower (410 kW) and 1850 Lb Ft (2,508 Nm) of torque from a low rpm, with a peak output of 578 horsepower (431 kW) ensuring plenty of power for a wide range of applications. If operators want even more power, they can also have the X15 in a 600 horsepower (447kW) / 2,050 lb.ft (2,2779 Nm) rating. For less demanding applications, alternative ratings from 485 horsepower (361 kW) and 1650 lb.ft (2237) upwards are available.
The engine also features an XPI (Extreme Pressure Injection) common rail fuel system which 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.
Operators who select the Eaton 18-Speed ‘UltraShift Plus’ automated transmission can also benefit from the optional ‘ADEPT’ package, a suite of innovative electronic features capable of further reducing fuel consumption by up to 6 percent.
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.
To meet stringent Euro 5 emissions requirements, the X15 features a fully integrated Selective Catalytic Reduction (SCR) system developed by Cummins Emissions Solutions (CES) which doses urea into the exhaust stream to reduce oxides of nitrogen (NOx) emissions.
The Cummins system is widely regarded as one of the best, using less AdBlue/DEF than competitor products.
Due to the high efficiency of the after-treatment system, the engine meets the Euro 5 requirements without the need for either Exhaust Gas Recirculation (EGR) or a Diesel Particulate Filter (DPF) which simplifies the engine design and reduces ongoing maintenance.