Mercedes Benz Predictive Powertrain Control (PPC) Review

As dawn tiptoed over the sleepy Derwent River beside Downer’s Austins Ferry depot, it promised a brilliant day for a test run with Michael Townsend in his new Mercedes Benz and Drake deck widener low loader.

Michael had picked up the Actros six months earlier, and the trailer followed two months after the arrival of the Benz. While Michael was keen to point out the features of his new trailer, he was also eager to demonstrate how the Predictive Powertrain Control (PPC) feature worked on the prime mover.

Surprisingly, traffic was light heading south down the Brooker Highway before Michael wheeled the Actros left and over the Derwent River and north through rural countryside, tackling tight corners and steep pinches effortlessly.

As expected, the 16 litre OM473 engine under the cab performed admirably through the undulating countryside. Complementing the formidable engine in the Actros 2658 is its sophisticated PowerShift transmission system, which plays a crucial role in translating engine power into smooth and efficient motion on the road.

Moreover, the PowerShift transmission utilised in the Actros 2658 is a state-of-the-art unit boasting advanced electronic controls and adaptive algorithms that continuously monitor driving conditions and driver inputs to optimise gear selection and shift points.

According to Mercedes Benz literature, this intelligent transmission not only enhances driving comfort and ease of operation but also contributes to fuel efficiency by ensuring that the engine operates within its most efficient rev range under all circumstances, and Michael agrees.

Michael explained that the overall aim of PPC is for the truck to save as much fuel as possible and to support the driver in the best possible way.

“Here in Tasmania, most of the major road network is loaded into the PPC system,” Michael said. “But I’m finding the truck is learning new routes over time.”

The system automatically considers topography, the course of roads, and traffic signs during its decision process. This means that unnecessary braking, accelerating, and gear shifting are avoided, and fuel usage is optimised.

The driving style of PPC is often more economical on fuel than that of a professional driver, even when the driver knows the route and the truck’s performance well.

PPC reduces fuel consumption on highways and major roads through several intelligent measures. For example, the system continuously optimises the EcoRoll mode of the automatic transmission to use the vehicle’s momentum in the best possible way.

The system dispenses with acceleration if the truck can soon reach the speed set by cruise control just by coasting. Also, the intelligent cruise control system and transmission control use the momentum on downhill stretches by automatically adapting the speed.

The system exceeds the set speed (upper hysteresis) of the cruise control for a maximum of 40 seconds to allow the truck to use its momentum on the subsequent uphill gradient.

Also, before the downhill stretch, PPC selects the gear that ensures optimum use of the continuous brake, thus reducing service brake usage; a significant advantage, particularly for heavy trucks travelling downhill. Before an uphill gradient, the system decides automatically if a gear downshift is required.

At the end of the ascent, the output is adapted once again because PPC can detect in advance before reaching the brow of the hill whether the truck has sufficient speed to roll over the brow. If it does, it tolerates a temporary slowdown to a speed lower than the speed set in the cruise control.

Michael says that once inside the cabin, you’ll quickly find one of the best-kitted European truck cabins available on the market. There is also ample space inside, and thanks to the flat floor, the driver can move through the cabin effortlessly.

To maximise driver ergonomics, the dashboard features a wrap-around design and is fitted with all the necessary controls, which are within easy reach and have a logical layout.

The instrument panel design, materials and layout are class-leading. When equipped with all the ‘toys’ of the superior trim levels, the truck’s ambience is impressive, with big, clear gauges, an uncluttered centre stack and tasteful trims spanning the dashboard. Combine that with the classy upholstery, complete with contrast piping, and you’ll see why this Actros cabin impresses.

The sleeper compartment in the Downer 2658 Actros is equipped with a full inner-spring mattress. However, Michael admits there’s little time to spend in the bunk on his short runs around the south of the state, but he adds that with the longer runs to the northwest, you can get a good night’s sleep in the bunk.

The PPC worked exceptionally well along the Midlands Highway section of our run. Michael has mastered the art of controlling vehicle speed by using his thumb on the steering wheel.

“I rarely touch the pedals now,” Michael explained. Once I’ve set the cruise control, the PPC automatically kicks in. But it’s not a set-and-forget operation. I constantly monitor the grades and make fine adjustments to the cruise speed to get the best economy, maintain a consistent speed, and, most importantly, not exceed the speed limit on the downhill sections," Michael said.

“The 3x4 deck widener low loader really suits the machinery we transport daily for our road construction operation,” Michael explained. “It is big enough to carry most of our mobile plant yet small enough to allow general access, which is critical to us. Today, we’re working on a section of a major highway, so access is not an issue. But tomorrow, we might work in an inner city cul-de-sac where access is extremely limited for big machinery like low loaders.

“This float sits on the road nicely,” Michael said. “I’ve towed a lot of different floats over the years, and I must admit that this one is one of the better and more stable floats I’ve had the pleasure of towing.”

“The hydraulic suspension plays a big part in the stability of this float,” he continues. “Like any piece of equipment, there are pros and cons, and it’s the same with floats. For example, some blokes argue that deck wideners are unstable because the wheels remain on the same wheel track. But I believe they’re a versatile piece of equipment if you load and operate them correctly.”

“One of the most significant advantages of a deck widener is that I can widen the deck to suit the machine width, but the wheels retain the same track as the truck. Consequently, it is ideal for operating on tight bush tracks and narrow farm laneways with narrow bridges.

The deck is 2.5 metres wide in the closed position and opens to 3.7 metres at the rated weight when fully extended. Another feature that adds to the versatility of this low loader is the bi-fold full-width ramps. There is ample storage for rachet chain turnbuckles in the gooseneck and dunnage trays under the deck. Adding the top deck on the gooseneck provides flexibility for a greater range of applications. The controls are on the left side of the trailer.

As the afternoon shadows started stretching longer on the ground, our day’s test run in the Mercedes Benz with PPC was an eye-opening experience. One of the most compelling advantages of PPC is its remarkable ability to deliver significant fuel savings. By intelligently anticipating road conditions and terrain variations, PPC cleverly optimised gear shifting, engine speed, and vehicle speed to achieve the most fuel-efficient performance possible. Not surprisingly, this proactive approach reduces fuel consumption and minimises wear and tear on the vehicle, leading to lower maintenance costs and extended longevity.

Moreover, the fuel-saving benefits of PPC extend beyond individual vehicles to entire fleets, where even marginal improvements in fuel efficiency can translate into substantial cost savings over time. By implementing PPC across their fleets, companies can improve their bottom line and contribute to a more sustainable future by reducing carbon emissions.

Specifications:
Make: Mercedes Benz
Model: Actros 2658LS 6x4
Engine: MB OM473 16-Litre
Horsepower: 580hp (426kW) at 1600rpm
Torque: 2800Nm at 1100rpm
Gearbox: MB G281 12-speed direct
Retarder: Engine Brake – standard system
Front Axle: MB 8.0T
Front Suspension: Leaf Parabolic 8000kg with anti-roll bar
Rear Axles: MB 440 Hypoid with diff locks to both axles
Rear Axle Ratio: 3.583
Rear Suspension: MB Air-suspension
Brakes: MB electronically controlled disc brakes
Safety: ASR with integrated ABS and traction control
Wheelbase: 3250mm
AdBlue tank: 60 litres
Fuel tank: 860 litres
Bumper: Polished alloy bulbar