The MX-13 is PACCAR’s 12.9-liter Class 8 engine, with power ratings from 380-500 hp (283-373 kW) and torque from 1,450-1,850 lb-ft (1,966-2,508 N·m).

PACCAR MX-13 Engine and Eaton Fuller Advantage 10-speed automated transmission.

PACCAR was the first engine manufacturer to utilize CGI in both the block and cylinder head of a heavy-duty diesel engine. With shorter and thicker graphite particles than standard gray iron, CGI offers stronger adhesion between the graphite and the iron giving this material in the MX-13 engine greater tensile strength and excellent thermal resistance.

CGI is 75% stronger and stiffer than gray cast iron, allowing for reduced wall thickness without compromising strength and optimizes the stiffness of the block and head. The result is a lighter, stronger cylinder head and block.

The MX-13 features a single, dynamically balanced camshaft made of high strength steel, further reducing the MX-13 engine’s weight and complexity. The single camshaft is located low in the block where it helps reduce engine noise and keeps the overall engine size very compact.

Peak fuel pressure of 2,500 bar at the injector tip allows for excellent fuel atomization and combustion, delivering improved fuel economy and low emissions.

A novel cam-actuated integral engine brake offers strong, quiet, and reliable braking performance with a low overall engine height.

The Eaton Fuller Advantage Manual Transmission is a lightweight, constant mesh transmission, and the first from Eaton to feature a cooler-less design to improve reliability and fuel economy while providing high levels of efficiency.

The new Eaton Fuller Advantage 10-speed automated transmission saves 70 pounds over the Eaton UltraShift PLUS LAS transmission and incorporates a new Precision Lubrication system that improves the efficiency of the transmission by reducing churning losses. That, coupled with new electronic controls between the engine and transmission, optimizes performance to make this transmission the most efficient we’ve ever offered in a Kenworth truck.

—Kevin Baney, Kenworth chief engineer

The Eaton Fuller Advantage automated transmission senses the load demand on the engine and selects the best shift points to match vehicle weight, road grade, engine torque and throttle position. It also has unique control logic and a small step gear ratio that enables downspeeding in top gear Overdrive, while allowing a quick down-shift to Direct-Drive 9th gear required when pulling a grade.

T680 Advantage aero enhancements. Click to enlarge.

Kenworth T680 Advantage. Kenworth had displayed a concept version of the T680 Advantage at the Mid-America show in 2013. Production of the commercial model began this month.

The Kenworth T680 Advantage features a special factory-installed aerodynamic package along with the optimized powertrain combination of the PACCAR MX-13 engine integrated with the Eaton Fuller Advantage 10-speed automated transmission. (The MX-13/Fuller package is also available in a standard T680, with about a 2% improvement in fuel economy.) Factory-installed aerodynamic treatments add to the fuel savings.

The aerodynamic treatments include longer side extenders for the T680 76-inch sleeper, lower cab fairing extenders, front air dam, aerodynamic mud flaps, rear fairing without steps coupled with an air deflector, exhaust cut out covers, and optional wheel covers for drive tires.

Kenworth Idle Management System. Click to enlarge.

Other fuel-efficient specs for the T680 Advantage include speed control management that utilizes speed limiters; a tire pressure monitoring system to keep tires at optimum PSI; and the new Kenworth Idle Management System, which eliminates the need to idle in order to run air conditioning.

The system offers a battery-based auxiliary power unit (APU) system for air conditioning that is tied directly into the Kenworth T680’s ducting system. An optional fuel-fired heater provides full engine-off heating capability.

Powered by four dedicated PACCAR batteries, the AC system has a small under-bunk footprint to maintain storage space for drivers and passengers. The Kenworth Idle Management System features full on-board controls in the sleeper to control both cooling and heating.

Kenworth will also offer natural-gas fueled versions of the standard T680. The Kenworth T680 day cab and 52-inch mid-roof sleeper will be available with the factory-installed Cummins Westport ISX12 G natural gas engine rated up to 400 hp (298 kW) and 1,450 lb-ft (1,966 N·m) of torque.

Peterbilt Model 579 with EPIQ. The new EPIQ package for the Model 579 provides an optimized combination of technologies and components for improved fuel economy. In addition to the MX-13/Fuller combination, the EPIQ package includes:

• Complete Aerodynamic Package: This feature combines all fairings and aerodynamically enhanced components available for the Model 579. The fairings include 18-inch sleeper side extenders with 8-inch rubber flares; full chassis fairings with rubber skirts from the quarter fender to the front of the tandem axle with rubber closeouts under the sides of the cab and sleeper; and roof fairings with an exclusive rear wall closeout. Aerodynamically enhanced components include a three-piece aero-style bumper; multi-piece aero-style hood; painted outside sun visor; and an aero-style aluminum battery box positioned on the passenger side, under the cab.

• Single Horizontal Exhaust: To further increase aerodynamic performance, the EPIQ package recommends a single horizontal exhaust configuration or a single right-hand back-of-sleeper exhaust configuration.

• SmarTire Tire Pressure Monitoring System (TPMS): EPIQ includes the TPMS to provide operators with real-time tire pressure information; TPMS monitors the pressure and temperature of each tire and will warn the operator of tire-related problems.

• Low Rolling Resistance Tires: Another way tires can improve fuel economy is by minimizing friction between tires and the road. Low Rolling Resistance Tires are designed to do this and are available on the Model 579 spec’d with the EPIQ package.

• Optimized Spec’ing Software: Peterbilt and its dealer network use a proprietary spec’ing system to optimize vehicle performance and exactly match customers’ business and application requirements. This software has been enhanced to complement the Model 579 EPIQ by recommending the most fuel efficient rear axle ratios and engine settings, among other options.

Peterbilt also announced it will offer compressed natural gas configurations for the on-highway Model 579 and the vocational Model 567. Both vehicles will be available with the Cummins-Westport ISX12 G engine.