HITACHI CONSTRUCTION MACHINERY

New hydraulic system HIOS III and new DOHC 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 DOHC** 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 8% in comparison to previous model ZAXIS-1.

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 by up to 14% compared to the previous model's P mode, while yielding similar production.

• Digging power is boosted by 6% when increasing pressure through use of the power digging power.

• Lifting capacity 7% up.

Increase in Swing Torque and Traction Force

• Swing torque and traction force are increased significantly.
  - Swing torque 10% UP
  - Traction force 3% UP
  

• Sophisticated Travel Control;
  At climbing or steering, when the machine needs more traction force, the engine speed 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 lower 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%.

DOHC 4-Valve Engine

The new DOHC 4-valve diesel engine is developed and built to comply with the rigorous Emission Regulations enforced in 2006 in U.S and 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 intake air to lower combustion temperature for reducing NOx and fuel consumption. 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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