The concept of redirecting friction issues isn’t limited to lift axles. It has extended to other axle configurations as well, as Dana Holding Corp. shows with its Spicer Dual Range Disconnect tandem axle concept. Optimized for trucks that implement engine downspeeding, this technology improves efficiency without sacrificing performance by combining the traction and dependability offered by a 6×4 with the reduced drivetrain losses and improved fuel economy of a 6×2, the company said.
According to Steve Slesinski, Dana’s director of global product planning, the concept employs a single gear mesh configuration from the engine to the wheels when combined with direct-drive transmissions. This can improve overall powertrain system efficiency from 2% to 5% compared with conventional 6×4 tandem axles paired with overdrive transmissions.
At startup, on grades, at low speeds, during backup maneuvering, or in other environments where additional traction is needed, Spicer AdvanTEK Dual Range Disconnect technology allows the tandem axle to operate as a 6×4 with a traditional (higher numeric) starting ratio that delivers the optimal tractive effort needed with reduced stress on drivetrain and chassis components. At low speeds, this ratio offers improved performance over fast-ratio 6×4 tandem axles by enhancing low speed maneuverability while reducing the likelihood of high torque spikes.
While a lift axle is controlled with a switch by the driver, Spicer Dual Range Disconnect technology uses an electronic control unit (ECU) in the axle to automatically coordinate with engine and transmission ECUs to disconnect the inter-axle shaft from the power divider, allowing the axle to operate in a more efficient 6×2 mode. At the same time, it shifts the forward axle to a faster ratio that enables the engine speed to decrease to as low as 900 RPM for highway cruise operation.
Slesinski added that by using separate axle ratios for low- and high-speed operation, this technology enables linehaul trucks to accelerate from low velocity to highway cruise speed much quicker than a 6×4 or 6×2 tandem axle with a single, fast ratio.
Dana has been evaluating prototypes of the Spicer AdvanTEK Dual Range Disconnect concept for the past three years and is moving forward with plans to integrate axles featuring this technology into manufacturers’ chassis for field testing.
