tors and other medium-sized equip- ment to large haul trucks. To reduce both NOx and PM while maintaining fuel economy, Komatsu said it needed to develop new engine technology to meet the emissions tar- gets. Adding to the complexity of the engine design is the application in
construction and mining, requiring continuous operation of maximum power output and torque, and creat- ing additional demand on the engine. For the new engine design Komatsu has introduced a redesigned vari- able geometry turbocharger (VGT), a heavy-duty high-pressure common rail (HPCR) fuel injection system and added alarger and more robustcooled exhaust gas recirculation (EGR) sys- tem. The engine also incorporates a diesel particulate filter (DPF). The newly designed VGT features Komatsu’s proprietary technology that the company said varies the airflow and is designed to deliver optimum air quantity to the engine combustion chamber based on en- gine speed and load conditions. The system purifies the exhaust gas, using higher-efficiency combustion, which Komatsu said improves fuel economy while maintaining power and performance. The computer-controlled, heavy- duty HPCR system delivers a pre- cise quantity of pressurized fuel into the engine combustion chamber using multiple injections to achieve complete fuel burn and reduce exhaust emissions. While HPCR has been applied to Komatsu’s existing engine line, the new design pressur- izes fuel at a higher point for injec- tion so that it can reduce both PM in the entire zone of engine revolution and fuel consumption. The lifespan of the fuel injector has also improved with ultra-hard wear-resistant mate-
Komatsu Launches Tier 4 Interim Engines Komatsu America Corp. has introduced a new genera- tion of engines to meet EPA Tier 4 interim emissions standards, reducing PM by 90% and NOx by 45% compared to Tier 3 levels, the company said. The new engines are integrated throughout Komatsu’s construction and mining equipment in multiple dis- placements from 3. 3 to 46 L. En- gines, hy-draulics, control systems and a number of other components are developed and produced by Komatsu in-house, which the compa- ny said allows it to design engines and equipment structures as an inte- grated whole. Some models within the Komatsu engine lineup are jointly developed and manufactured by Cummins Inc. The new engines will specifically be used on the PC120 hydraulic excava-
Komatsu America Corp.’s new Tier 4 interim engine. The new engine will be available in multiple displacements from 3. 3 to 46 L for integration in Komatsu’s construction and mining equipment.
Komatsu has incorporat- ed a redesigned variable geometry turbocharger to its engines. The VGT varies the air flow to deliver opti- mum air quantity to the en- gine combustion chamber based on the engine speed and load conditions.