Volvo unveils powertrain enhancements, boosts fuel economy

John G Smith

 

HAGERSTOWN, MD – Volvo Trucks North America has unveiled a series of powertrain enhancements today, highlighted by changes that will transform wasted heat into horsepower, bring the automated I-Shift and downspeeding to vocational haulers, and a cruise that memorizes terrain.

The D13 engine with turbo compounding will capture wasted exhaust heat and transform it into 50 extra horsepower thanks to options available by mid-2017. “Volvo’s a leader in downspeeding, and we plan to take that even further,” said Wade Long, director – product marketing. “We’re going to bring fuel efficiency to the heavy-haul market.” With a fast 2.47 rear axle ratio, fuel economy could jump 6.5% over a comparable 2014 D13 engine.

“It brings back driveability to the truck,” Long adds. “When drivers press down on the accelerator, they want the vehicle to go … we’re able to ramp up that horsepower very fast.” When the engine is combined with the XE powertrain package, operations that run at less than 90 km-h will be able to cruise at 300 rpm less than usual.

It isn’t the only change to Volvo’s engine lineup. Several enhancements to the D11 and D13, available as of January 2017, include a common rail fuel system, reshaped “wave” pistons that promise to lower soot loads, and a two-speed coolant pump to reduce parasitic losses. 

The D11 ratings increase to 425 horsepower, while fuel efficiency rises 2.2%.

The D13 will itself see fuel economy improve by 2.5%, and 100 lb ft of extra torque on the 455-horsepower model will reduce the need to downshift on rolling hills. “If you’re taking that grade at sixth gear, maybe you’ll be able to take it in seventh gear. Or better yet, if there’s rolling hills, we can stay in 12th gear,” Long says.

While diesel is traditionally injected into the centre of a piston and spreads outward, the fuel will now be directed toward six tabs around the circumference of a wave-shaped piston. This causes the fuel to swirl inward, increasing the compression ratio and eliminating wet spots on cylinder walls that can otherwise transform into soot. The soot levels were so low during tests that engineers thought their original results were faulty, says Long. “They’re actually just burning that clean.” Could this open the door to extended oil drains? Perhaps. Volvo confirms it is testing the idea.

The common rail system and dosing valves are also fully contained under the valve cover. “There is no external low-pressure and high-pressure pump,” Long says.

Meanwhile, the company’s popular I-Shift automated manual transmission and new crawler gears will be available as an overdrive in VHD, VNX, VNM and VNL models with D11, D13 or D16 engines. Fitting inside an extra five-inch envelope on the end of the transmission, the new gears open the option of automation to heavy haulers with Gross Combination Weights up to 220,000 pounds, and even applications such as concrete mixers that need to pour curbs at slow speeds. Collectively, the equipment and related lubricant will add 90 pounds.

Heavy haulers that have been running 140,000 pounds at 1,500 or 1,600 rpm on the highway, with a 3.58 or 3.73 rear axle ratio, could now see ratios of 3.21 or 3.08 without sacrificing startability. “Then we can give them the cruise speeds,” Long says.

The new option will be available with 14 forward gears including a low crawler gear with a 19.38 gear ratio, and an ultra-low crawler gear with a 32.04 gear ratio, making it possible to run less than 1 km-h at 800 rpm with a 3.58 rear axle ratio. Another version will come in the form of 13 forward gears, including one low crawler gear (17.54 ratio).

“There were lots of people telling us that automated manual transmissions will never work in North America, will never be accepted,” observed Goran Nyberg, president of Volvo Trucks North America. This takes another step toward proving them wrong.

The I-Shift’s brain will also be able to benefit from a new set of eyes. The I-See system combines a grade sensor and GPS unit to memorize the hills on a particular trip, combining that with data about speeds and weights along as many as 4,500 routes. When the truck repeats a route, the technology can help to enhance fuel economy through actions such as speeding into a hill, or rolling in neutral over the hill’s crest thanks to something known as an “Eco-Rolling”.

Introducing the new I-Shift and crawler gears into an XE Adaptive Gearing package will protect startability and slow-speed performance on softer ground, Volvo says.

Meanwhile, the D11 and D13 Selective Catalytic Reduction (SCR) and Diesel Exhaust Fluid (DEF) doser will now fit into a single unit – officially known as the One-box Exhaust Aftertreatment System – that sheds 17 pounds from its two-box predecessor and reclaims an extra 12 inches of space on the frame rail. That space can be used for everything from fuel and hydraulic tanks, chain carriers, or even add auxiliary axles.

It isn’t the only way that unwanted pounds are being shed. Volvo’s common rail fuel systems are coming to North America, reducing the load on the engines and introducing a hollow camshaft that is 40 pounds lighter than its solid, machined predecessor.

Mechanics will notice other changes. The valve cover on the D11 and D13, once made in a single-piece, will come in two pieces, eliminating the need to unplug the engine harness linked to the injectors. A seal retains oil in the bottom section. And where rockers were once shimmed to adjust valves, no shims are required, effectively halving the time for such work, Volvo says. A swivel cover on the face of the new One-box Exhaust Aftertreatment system, meanwhile, allows quick access to the DPF. Even the entire SCR and DPF unit can be pulled off by removing six fasteners.

A new double-wall casing on the EGR flow sensor is expected to reduce condensation and soot in cold weather, and an improved aftertreatment dosing module has been introduced into the fuel filter’s housing, improving serviceability. The friction material on cylinder walls has been enhanced to reduce parasitic losses.

All the high-pressure fuel lines have also been routed under the valve cover on the D11 and D13. “What we discovered is how quiet these engines are,” Long added. “I think the drivers are going to appreciate these new engines.”

 

John G Smith

John G. Smith is the editorial director of Newcom Media's trucking and supply chain publications -- including Today's Trucking, trucknews.com, TruckTech, Transport Routier, Inside Logistics, Solid Waste & Recycling, and Road Today. The award-winning journalist has covered the trucking industry since 1995.

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