Looking at the International ProStar as it re-enters the Australian truck market, this is not a truck with massive pretensions. It has not been introduced onto the market with massive claims about gaining a high market share or revolutionising trucking in Australia. This is a truck which Iveco hope the Australian truck buying public will warm to, because it ticks all of the boxes and makes operators money.
At the basic level we are driving a 15 litre Cummins with a nice spiky torque curve, coupled with a bulletproof 18 speed Roadranger transmission , pushing through to a Meritor backend and sitting on a Hendrickson suspension. This is all pretty familiar and could have been said 15 or 25 years ago.
All of those basic components are in there still, but with a few add-ons and considerable development. Probably the most dramatic change has been in the transmission department with the advent of the Ultrashift Plus. This is a smart gearbox with plenty of added extras to make it function accurately.
15 years ago the industry relied on the reliability of the Roadranger’s constant mesh set-up, but was struggling with Eaton’s first foray into AMT, the Autoshift. To describe the Autoshift as clunky would be an understatement. There was a major gulf between the capabilities of this AMT and those which were coming out from Europe at the time.
Dial forward to the present day and the Ultrashift ticks most of the boxes ticked by its European opposition, both the closely related offerings from Volvo and ZF, and the synchro style Opticruise from Scania.
The transmission now includes an inclinometer, it knows whether the truck is going up or down hill and how steep the incline is. This helps in gear selection, especially when the Adept integration system which allows the Cummins engine and the Eaton transmission to talk to each other, is part of the package.
The transmission knows the steepness of a climb and, armed with data about how much torque is being used by the engine to maintain its speed. It can calculate exactly when to change gear and how many ratios to skip to keep momentum up on the climb. Of course, the driveline doesn’t know if a grade is about to start, but its fully informed once the truck is climbing or descending.
Another of the smarts which this driveline has, which performs particularly well in a situation like those of this test is the SmartCoast function. Driving the undulating Pacific Highway with 62 tonnes of B-double on the back gives the transmission plenty of opportunities to use this facility and reduce driveline drag to let the combination coast at 100 km/h.
In the Cummins/Eaton version of this type of system the coasting opportunities are maximised by the parameters which have been set for when to activate SmartCoast. The truck needs to be traveling at 100 km/h, the truck’s momentum is enough to maintain this speed, the driveline isn’t needed to do so. Once this is the case, the clutch is opened.
This means the truck will have the clutch disengaged more often and for longer than it often is on the European versions of this technology. The truck makers in Europe are, famously, conservative in their approach and will only let the truck coast when the conditions and fail safes are absolutely perfect. The Adept system has taken a more aggressive approach and will safely take advantage of the right conditions when they appear.
Performance is further enhanced by the SmartTorque management technology. This uses the data shared between engine and transmission to maximise the amount of time the engine is running in its sweet spot. Knowing the gross mass, the speed, the drag and the incline, it can supply enough torque to maintain momentum to avoid unnecessary down-changing and improve fuel consumption.
