The low-hanging fruit when it comes to fuel economy has all been picked. Now truck and engine makers are examining every part and component of the truck in exacting detail to figure out where they can cut the smallest amount of drag or the small parasitic loss of power that drag down fuel economy. Here are two examples used on the Freightliner Cascadia Evolution:
No Antenna Drag
Bulky cab and roof antennas will no longer cause air resistance in the new generation of Freightliner trucks, while making it impossible to damage the antennas during operation.
A unique film antenna package developed by Hirschmann Car Communication Inc. can be integrated in the body of the tractor unit. It requires no external components, and the company says it achieves the best transmission and reception quality for CB radio, AM/FM stations and weather information radio channels.
The antennas are adapted to the available installation space, fitting perfectly between the structural body panels and the interior lining of the cab. They can’t be seen from the inside or the outside of the truck.
The collaboration with Freightliner began five years ago. After developing and testing, the prototype was featured on Freightliner’s aerodynamically optimized Innovation Truck in 2009. The concept led to the development of the new model, the Cascadia Evolution, which was launched in January 2013.
Demand-Driven Coolant Pumps
Behr’s patented Visco technology for engine-coolant pumps reduces “parasitic” power losses that affect fuel economy. First introduced on 13-liter diesel engines in Europe, Behr’s new demand-driven system recently became available on commercial vehicles sold in North America.
Behr says its system has the potential to reduce annual fuel costs for long-haul truck operators by up to 1% per vehicle.
The electronically controlled Visco system varies coolant-pump speeds based on engine requirements and operating conditions. Variable-speed Visco fan drives for truck engines have been available since the 1970s, but this is the industry’s first coolant-pump application.
Heavy-truck coolant pumps today are almost exclusively tied linearly to engine-speed via belt drives. Since these pumps are designed to meet coolant requirements under maximum load conditions, flow rates at many operating points exceed actual need, with a resulting drain on fuel economy.
Behr’s technology hydraulically isolates engine-input speeds and minimizes power consumption under high-speed operation and light-engine loads where maximum flow rates are not required.
The Visco pump’s control logic is embedded in an engine-control module. Although the pump is tied to a belt drive, energy is transferred hydraulically to an impeller. The amount of energy transfer depends on the amount of silicone oil in an operating chamber managed through a closed-loop control system.
Daimler Trucks North America says it is using a similar technology on the newly designed DD15, which is exclusively available in the Cascadia Evolution.
“We refer to it as the ‘variable speed water pump’,” explains Brad Williamson, manager of engine and component marketing for DTNA. The pumps “decrease parasitic loss when the engine temperature is such that we don’t need to flow ‘normal’ levels of coolant.”
Cummins, on the other hand, recently introduced a new global engine platform, the G Series, which it says “offers fuel efficiency through parasitic-reducing technology without variable-flow pumps that add unnecessary cost and reduce reliability.”