Hydraulic-hybrid technology gains momentum
Hydraulic-hybrid technology for commercial vehicles is moving closer toward volume production thanks to a joint effort by two manufacturers.
According to Ward’s Engine and Vehicle Technology Update (WEVTU), a demonstration is slated for January 2005 for hydraulic-hybrid technology developed jointly by Dana Corp. and Australia’s Permo-Drive Ltd. The developers are targeting fleet operators of frequent-stop vehicles seeking fuel and maintenance-cost savings from a less-costly hybrid powertrain system.
The hybrid demonstrator is a garbage truck based in the Los Angeles Basin and sponsored by California’s South Coast Air Quality Management District (SCAQMD). SCAQMD is seeking a fullsize refuse truck, GVW 70,000 lbs., that will deliver significant emissions reduction and fuel-economy gains. The LNG-fueled truck will employ a 350-hp capacity hydraulic pump/motor unit that requires 3.6 cu-ft. of space mounted in the driveline. It provides more than 1,500 lb.-ft. of torque.
Edward J. Greif, Dana vp— intelligent hydraulic drive products, told WEVTU the system and its derivatives for smaller commercial vehicles (such as package delivery trucks or vans) will permit fuel and brake-repair cost savings comparable with electric hybrids— but at a lifetime cost of “less than one third compared with electric systems. We expect to be in volume production with fully-developed and tested products within four years,” he added.
Frequent-stop hybrid vehicles typically cut fuel use by one-third and brake repair by more than half, noted WEVTU.
According to WEVTU, hydraulic-hybrid technology sports many advantages over HEV— mainly related to much lower initial costs and maintenance costs, as well as its proven fluid-power technology. However, its main disadvantage is its usefulness in a relatively narrower range on driving applications. It is also said to be noisier, although Greif doesn’t consider hydraulic noise to be an issue for commercial trucks.