Compressed natural gas and hydraulic hybrid systems were the big equipment news at this year's Waste Expo show, held in Dallas, with most refuse haulers looking at the two alternative power options to help them save fuel and reduce carbon emissions.
The Autocar E3 packer is powered by a full-series hydraulic hybrid system supplied by Parker Hannifin Corp. Called RunWise, it replaces a standard transmission with a hydrostatic drive module that allows it to capture kinetic energy on braking, which it stores by compressing hydraulic fuel. The unit provides all vehicle braking down to 5 mph, generating as much as 500 hp. for storage, according to Vance Zanardelli, Parker Hannifin's business unit manager for energy recovery. The system then uses the compressed hydraulic fluid to drive the truck at all speeds under 42 mph. Above 42, power is provided by the E3's 380-hp. Cummins ISL diesel linked in direct drive to the real axles.
In tests with Miami area refuse fleets, the E3 cut fuel consumption on collection routes by 42%, servicing up to 1,000 houses a day, according to Zanardelli. Autocar has begun taking orders for the E3 and it is in limited production. A delivery package van using the Parker system in a Freightliner Custom Chassis vehicle is also about to begin field testing, Zanardelli told Fleet Owner.
The hydraulics group of Eaton Corp. has taken a different approach, developing multiple hydraulic-based systems designed to reduce fuel consumption in refuse collection applications. Its hydraulic launch assist system inserts a hydraulic pump/motor behind a standard transmission. In the stop-and-go of refuse collection, it captures energy on braking, which it stores by compressing hydraulic fluid in a holding tank, explains Corey Moore, the hydraulics group director of commercial vehicles. The pump then switches to motor mode to provide the initial seven to eight seconds of power for vehicle launch.
A fleet can choose to set the system for maximum fuel conservation, which can deliver up to a 20% improvement in mpg, or for faster launch performance to increase truck productivity, which will still offer a 14 to 15% fuel improvement, said Moore. Currently, Peterbilt is offering the hydraulic hybrid system as a production option, and Mack has begun trial installations.
Mack brought its TerraPro COE fitted with a 9L, 320-hp. Cummins Westport ISL G natural gas engine. Capable of running on compressed natural gas (CNG), liquefied natural gas (LNG) or landfill gas (LFG), the engine has a three-way catalyst that allows it to meet EPA 2010 emissions standards.
Freightliner's alternative power option for the refuse market is its M2 112 natural gas model. The 320-hp. ISL G engine has a stack of five CNG tanks that mount behind the cab and provide fuel capacity equivalent to 75 gals. of diesel.
Navistar's natural gas version of its International WorkStar is powered by a modified version of the company's own 7.6L MaxxForce DT engine. Producing a peak 300 hp. and 860 lbs.-ft. of torque, the engine's conversion from diesel is handled by Emission Solutions Inc. (ESI), with the NG version installed off the assembly line. GVW ratings go up to 72,000 lbs. for the CNG WorkStar.
