Historically, says Long, “running engine cruise speeds at lower rpms shook the mirrors off the truck.” But Volvo Trucks pioneered the downspeeding revolution in 2012, introducing smooth-driving packages that integrated the engine, transmission, software, rear axle ratios and tire sizes.
Now, says Long, with a new generation of engines, I-Shift transmissions, software and trucks, “we can make application-specific solutions with our XE packages that exceed our customers’ expectations for fuel efficiency and driver productivity.”
This truck exceeds customers' expectations for fuel efficiency and driver productivity
TC for extra XE Although all Volvo engines can be configured with XE packages, product marketing manager John Moore says the biggest improvement comes when you drop a new D13 Turbo Compound (TC) engine into a new Volvo VNL.
In the Turbo Compound, heat energy escaping the engine is captured by the turbo flywheel and redirected back into the system. When the engine creates peak torque, it also creates the greatest amount of heat energy.
The D13 TC, combined with the right rear axle ratios, can generate peak torque while cruising as low as 1050 rpm. The engine offers shift points with full power down to 950 rpm.
“The beauty there is, the engine is saving fuel because it’s running at lower rpm, but also driving a turbo unit that’s maximizing efficiency at peak torque,” Moore says. “It’s a win-win for fuel efficiency and performance, plus there’s less wear and tear on the engine because pistons are running less.”
A new XE Another recent development is the XE-Economy package. XE-Economy switches torque curves in more gears, depending on the engine load. While providing torque on demand — say, when climbing hills — the XE-economy package utilizes I-Shift transmission and rear axle ratios to save fuel when high torque isn’t needed.
Adaptations Other improvements provide more savings. Adaptive Gearing works with the Volvo I-Shift to lock out the top gear on a fully loaded truck for better performance. When the truck unloads and returns empty, the top gear is available to run more efficiently at lower rpms.
“That lets the driver get home faster and it’s more fuel efficient in overdrive,” product marketing manager Allison Athey says.
Taking a load off Athey says Adaptive Loading works much the same way. Proprietary software senses load weight and torque requirements. When appropriate, the truck automatically lifts an axle off the road to run more efficiently.
Integration, says Athey, is the key. “We build specific software in the engine that knows when to shift at lower rpms to manage the torque.”
“But all our components are fully integrated. They speak the same language. They are literally tuned, built, and made to work together.”