Performance with style

The 500–550hp segment is one of the most populous in the Australian heavy truck market. Prime movers need to be capable of handling B-double tasks, yet not be over-spec’d (or overpriced) for single trailer applications. A Sydney-to-Melbourne trip in a 2653 Mercedes-Benz Actros with a single trailer hooked up confirms Daimler Trucks has read the Australia market well.

We were first exposed to the Actros 2653 last year, when a Classic Cab prime mover was included to make up the numbers in the drive program to launch the Actros rigid range. A brief steer around the Toowoomba tableland only whetted the appetite for a more extensive drive of Mercedes-Benz’s 530hp offering.

By the time the ‘new’ Actros range was officially released in Australia in late 2016, we were already quite familiar with the trucks. We had taken the opportunity to partake in interstate drives in several of the 20 ‘assessment’ vehicles included inn the 1.8 million–kilometre Australian trials of pre-production models. Internationally, the latest-generation Actros has completed 50 million kilometres of testing. Our own drives have been spread over around two years, and it was interesting to note the progression of improvements between the early examples and the trucks that ultimately became the production vehicles available to Australian operators.

The Actros 2653 utilised on this recent Sydney-to-Melbourne trip is the L-cab Stream Space cabin, which at 2.5m is 200mm wider than the Classic Space cab we drove briefly in Queensland last year. The larger Stream Space cab sits higher on the truck’s frame than the slightly more compact Classic version, and is readily identified by the extra sections in the grille and the additional step to be negotiated to access the cab. This increased height means that a perfectly flat cabin floor has been achieved, which greatly improves internal mobility and bunk access, and enhances the general feeling of spaciousness. The smaller Classic Space cabs are definitely far from claustrophobic, despite having a modest 170mm floor tunnel required to clear the engine.

The bunk has a locally sourced inner-spring mattress and is 2,200mm x 750mm in this larger cab. Mounting points are pre-installed for a second tier bunk, should it be required. A number of non-slip rubberised horizontal surface storage areas are located around the dash to keep loose articles such as work diaries in place. A slide-out fridge and matching locker are located beneath the bunk area.

The 510hp remains available mainly for low-roof cabs in short-haul applications, and the addition of the 530hp specification is intended more for the high roof line sleeper-cab category that is such a mainstay for Australian long-haul applications.

In this 530hp (390kW) rating, the power comes from the 13-litre OM471 engine, which has up to 2,600Nm of very usable torque. The maximum power is developed at 1,600rpm, with the peak torque range spread across 1,100–1,400rpm. To reach the Euro-6 emission standard – which is not yet mandated for Australia – the Actros uses exhaust gas recirculation, AdBlue urea injection, and an oxidation catalyst combined with a diesel particulate filter that requires no maintenance.

The engine is fitted with an asymmetric turbocharger with two different sized orifices that direct exhaust gases onto the turbine wheel. The larger inlet is for high-speed power, with the smaller nozzle used to maintain grunt at lower engine revolutions. Developed specifically for the Mercedes-Benz version of the Daimler 13-litre platform, the turbo design eliminates the moving parts found in variable geometry turbos, without sacrificing engine performance.

The three-stage engine brake provides up to 400kW (536hp) of driveline retardation, which almost exactly matches the engine’s power output in this 530hp spec. The engine brake can be activated automatically when the service brakes are engaged. When the engine brake is working, three engine cylinders are used in phase one, six cylinders are used in phase two, and all six cylinders, the EGR valve and the turbo wastegate are used in phase three for optimum braking power. For heavy haulage or for routes that involve frequent long descents, an optional water retarder offers maximum braking force of up to 750kW.

The service brakes are disc brakes all round, with an anti-lock braking system (ABS) and anti-slip regulation (ASR). Due to the oblivious behaviour of one car driver, we are forced to test the brakes very early in the trip in an almost emergency-stop circumstance and at around 50km/h. The rig stopped safe and straight in what seemed to be its own length.

The automated manual transmission (AMT) is the Mercedes-Benz Powershift 3, which is a 12-speed that combines with the 2.733:1 rear axles to operate in excellent harmony with the engine’s torque and power characteristics. The combination’s gross weight for this journey is 42.6 tonnes, and the transmission makes the most of the engine’s ability to hold on to higher gears when lugging down around the 1,000rpm mark. Automated manuals such as this are now the norm rather than a novelty, and their contribution to improved fuel economy and reduced driver fatigue cannot be ignored. On only one occasion on the journey along the Hume are we tempted to override the electronics and initiate a down shift when climbing a grade but, by the time we check the tach and move our right hand a few centimetres to the control stalk on the right and side of the steering column, the Powershift 3 had seamlessly made the change anyway. Toggling down a gear or two on the steeper downhill sections significantly boosts the effectiveness of the engine brake system, and it’s a very rare occasion that we have to give the brake pedal a gentle squeeze to maintain safe and legal speed.

The transmission’s Eco-Roll feature disengages the driveline in appropriate circumstances, returning the engine to its idle speed and harnessing gravity and momentum to propel the truck. The re-engagement, either automatically via the cruise control or by applying the accelerator pedal, is as slick as the gearshifts.

The front suspension is a three-leaf setup rated at eight tonnes, and the rear is the familiar Mercedes-Benz airbag system. This truck is fitted with the larger optional aluminium fuel tanks, with capacities of 700 litres on the kerb side and 400 litres on the driver’s side. The standard AdBlue tank holds 60 litres, with a 110-litre version available.

The new Mercedes-Benz Telematics product utilises factory-fitted hardware and an Australian-developed software suite. Every truck comes off the production line with the hardware fitted and it is up to the customer if they want it activated. Mercedes-Benz has been encouraging the uptake by offering the first 12 months of Telematics at no charge. In addition to the desktop portal with full functionality, Mercedes-Benz Telematics also includes innovative apps for both the fleet operator and driver. The Telematics App allows the fleet operator to view a large amount of real-time data on each truck, including vehicle location, driving behaviour, alerts such as over-speeding, sudden braking instances and geofence breaches. The Driver’s App offers driver ID functionality and provides access to driving data.

The Telematics hardware can also be retrofitted to selected earlier models to aid with fleet integration. The system also allows for alerts to be sent regarding extreme vehicle incidents and uses the Telstra 3G network. It features on-board memory that can retain three months of data when not in GSM (mobile network, ed.) range, has a battery back-up system and a secure encrypted cloud portal.

The Driver’s App comes as part of the Mercedes-Benz Telematics suite and is available for both Android and iOS platforms. It offers customers a range of options, including the ability for drivers to conduct a real-time pre-inspection on each truck, with an option to upload comments and even photos that are immediately sent to the fleet manager.

At the end of our trip, the telemetry confirms the distance travelled at 821.02km, 352.73 litres of fuel used – 11.71 litres of which used while idling, mostly due to being stopped at roadworks – and a calculated average fuel burn of 2.41 litres per 100km. Normally we don’t pay a lot of attention to fuel consumption on test drives as we prefer to put a truck ‘through its paces’, rather than concentrating on squeezing the best economy figures to serve as some sort of bragging rights. Maximising economy is best left to the professional drivers who work the roads and highways every day.

The average speed for the journey is 89.97km/h. This truck is rated at 70 tonnes and obviously responds well to having just a single trailer in tow. It was able to maintain good road speed on the Hume’s hills and in most of the incline situations along the highway dropped only one gear.

In addition to the obvious efficiency and safety factors, Mercedes-Benz says that many customers are influenced by financial options including the ‘Agility’ guaranteed future value program, under which the truck can be sold back at a pre-agreed price.

Look beyond the sophisticated electronics and this is still a remarkable truck. The Actros has already been very well received by the market in Australia and, significantly, has found favour with many first-time buyers of European trucks who would have previously been devotees of American iron.

Fast Fact

The Actros can be optioned with additional electronic assistance packages, including Proximity Control Assist, Adaptive Cruise Control and Active Brake Assist.