HITACHI CONSTRUCTION MACHINERY

New hydraulic system HIOS III and new OHC 4-valve diesel engine were developed for ZAXIS-3. These advanced technologies are at work to yield bigger output with higher fuel efficiency.

Increased Production
A combination of the hydraulic system (HIOS* III) and new OHC** 4-valve engine allows the efficient use of hydraulic pressure to increase speeds of actuators and boost production with higher fuel efficiency. The productivity is increased with 11% in comparison to previous model ZAXIS-1.
_{* Human & Intelligent Operation System
**OverHead Camshaft}

New E-mode
The new E mode, H/P mode and P mode can be selected to suit job needs. The new E mode can save fuel consumption 15% more than the previous P mode, while yielding similar production.

Increase in Swing Torque and Traction Force
Swing torque and traction force are increased significantly.

• Swing torque 10% UP

• Traction force 11% UP

Traveling High Power Mode; At climbing or steering, when the machine needs more travel speed, the engine power automatically increases which makes the machine faster.

ZAXIS-1 adapted HIOS II hydraulic system that is suitable for fine controllability by the operators. Continuously HITACHI developed new advanced hydraulic technology HIOS III for ZAXIS-3. In addition to the fine controllability this new system increases the efficiency of hydraulic circuit and increases speed of actuators.

The Hydraulic Boosting System
In arm roll-in and boom-raise operation, excess pressure oil is delivered from boom cylinder rod side to arm cylinder bottom side to increase flow rate for higher arm roll-in speed with 20%. Excess pressure oil from boom cylinder rod side is delivered to arm cylinder bottom side through a regenerative valve to increase flow rate for productive operation.

Enhanced Boom Recirculation System
In combined operation of boom and arm, pressure oil from boom cylinder bottom side is delivered to boom cylinder rod side, assisted by boom weight, for boom lowering. At the same time, pressure oil from the pump is delivered to the arm cylinder for arm movement. This mechanism allows an increase of speed in combined operation of 15%.

Development concept of new engine
The new OHC 4-valve diesel engine is developed and built to comply with the rigorous Emission Regulations enforced in 2006 in EU. This new engine contributes to environmental preservation. At the same time it realizes high durability and low fuel consumption by adapting the latest advanced engine technology.

Common Rail Type Fuel Injection System
Electronic control common rail type fuel injection system drives an integrated fuel pump at an ultrahigh pressure to distribute fuel to each injector per cylinder through a common rail. This enables optimum combustion to generate big horsepower, and reduce PM* (diesel plume) and fuel consumption.

Cooled EGR** System
Exhaust gas is partially mixed with suction air to lower combustion temperature for reducing NOx. What's more, the EGR cooler cools down exhaust gas to increase air concentration for complete combustion, reducing PM* (diesel plume).
_{*Particulate Matter
**Exhaust Gas Recirculation}

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