Komatsu Introduces Its 911.5 Harvester

Komatsu's new 911.5 harvester uses SCR technology to meet Tier 4 Interim emissions regulations.

The new Komatsu 911.5 EPA Tier 4 Interim compliant harvester replaces the 911.4 harvester and continues to provide the high levels of performance, reliability, serviceability and operator comfort that earned the 911 its reputation in the market.

911.5 SCR Technology

The primary change to the 911.5 is the incorporation of Selective Catalytic Reduction (SCR) technology that meets Tier 4 Interim regulations. The SCR emissions reduction process takes place after combustion to maintain high engine performance. When combined with a high pressure common rail electronic injection system and new pistons, improved combustion efficiency reduces fuel consumption and particulate matter (PM). Low PM levels eliminate the need for a diesel particulate filter and the high temperature regeneration process. Field studies have documented reductions in fuel consumption of up to 15% compared with current Tier 3 powered machines. Actual fuel savings will depend on engine load factors, operator techniques, terrain and forest type. Fuel savings are the result of new engine technology, well matched and optimized hydraulic system and a networked machine control system.

The 911.5’s SCR system uses a relatively simple process where hydrocarbons and NOx emissions are reduced using catalytic converters together with a urea solution called Diesel Exhaust Fluid (DEF). Precise metered amounts of DEF are injected into the exhaust stream before entering a catalytic converter where it vaporizes and decomposes forming ammonia and carbon dioxide. Inside the catalytic converter, ammonia and the catalyst convert NOx to harmless nitrogen and water. The high pressure common rail electronic fuel injection system creates more efficient combustion to reduce particulates, so no advanced particle filter is required. Similar techniques are used today by many on-highway truck engine manufacturers in Europe and are a well proven technology.

Other Improvements

The Komatsu 911.5 rear swing axle has been upgraded to the new trunion bearing mounted axle used on the larger 931 harvester. This stronger reinforced cast axle has stronger stabilizer cylinder mounts and brake lines integrated into the axle housing. Hydraulic connections have been upgraded to O-Ring Face Seal (ORFS) seals throughout the machine for fewer leaks. Improved hose routing across the articulation joint further improves hydraulic reliability. The engine air filter has been upgraded to a new higher capacity design with an integrated cyclone type pre cleaner. The filter housing has a quick snap closure for easier service and maintenance. An improved engine air intake has been relocated to provide colder intake air for improved engine performance.

MaxiXplorer, Komatsu’s MS Windows based machine and head control system has been improved with a new software update for SCR engine support and enhanced harvesting head functions.

The 911.5 is now available with the Komatsu 365 three roller, four motor harvesting head. The 365 high performance head will be available with full 10 m (32 ft. 10 in.) reach on the CRH18 crane.