Komatsu has globally released the HB335LC-1, a 35 t version of its award-winning Hybrid excavator. It features the same Komatsu-designed Ultra Capacitor-based slew-energy regeneration system as on Komatsu’s proven 20-t class HB205-1 and HB215LC-1 Hybrid excavators. The first commercially available hybrid excavators on the global market, there are now more than 2,000 units operating around the world. As with the 20 t-class Hybrids, the new HB335LC-1 combines unique features to deliver fuel savings and environmental benefits. It combines Komatsu’s Ultra Capacitor with an inverter, motor generator and electric swing motor and the engine, all optimally controlled to suit the work situation.

The electric swing motor/generator captures and regenerates energy as the upper structure slows during slew operations, converting it into electrical energy. This regenerated energy is stored in the Ultra Capacitor, used by the electric swing motor to rotate the upper structure and also used by the generator/motor to assist the engine when it needs to accelerate – reducing fuel consumption and operational costs significantly.

The HB335LC-1 should bring significant fuel-saving and CO2 reduction benefits to 35-t class excavators. It is reported that depending on application, customers could see an average fuel consumption saving of 20% from the new 35-t Hybrid excavator.

According to Amber Rickard, Komatsu Australia’s National Business Manager, “conventional Komatsu excavators are recognised as being among the most fuel-efficient on the market – and Komatsu Hybrid owners have been saving thousands of dollars a year in diesel costs,” she said. “Over this same period, Hybrid owners have seen the same high levels of reliability, production and performance they are used to with conventional Komatsu excavators.

“This means that purchasers of Komatsu Hybrid excavators can do so secure in the knowledge they are investing in a fully proven concept which has successfully logged millions of operating hours worldwide since its initial launch in selected markets in 2008,” she said.

“Komatsu is strongly committed to environmental conservation and also dedicated to developing new and innovative products which improve performance and efficiency – and the Komatsu Hybrid excavator is the perfect combination of these ideals.

“Komatsu really does lead the way with Hybrid excavators and also has the added benefit of technical expertise and experience in Hybrid excavator technology spanning more than a decade.”

In a Komatsu Hybrid excavator, a standard Komatsu diesel engine is combined with a generator and electric motors, allowing engine output to be converted into both electrical and hydraulic energy.

The result is that energy conversion and transmission losses are reduced, while kinetic energy developed by the machine’s upper structure during slew braking operations is regenerated. This is achieved through a Komatsu-designed Ultra Capacitor to store electrical energy.

Using electrons and ions for charging and discharging, it allows for instantaneous discharge of electricity and hence very efficient recovery and storage of regenerative power.

The Komatsu Hybrid electrical system consists of three main components:

1. An electric generator motor

2. An electric swing motor generator

3. A Komatsu-designed Ultra Capacitor with inverter.

The generator motor is positioned between the engine and hydraulic pumps, the electric swing motor generator is used in place of the hydraulic swing motor and the inverter/Ultra Capacitor is used to rapidly convert and store electrical charge.

The electric swing motor generator uses electrical power from the inverter/Ultra Capacitor or the generator motor to drive the excavator upper structure during the swing function.

During the deceleration or swing-braking phase, the electric swing motor generator converts kinetic energy back into electrical power and returns it to the Ultra Capacitor via the inverter.

The generator motor generates electric power with engine torque to drive the swing motor or to charge the capacitor when necessary.

The inverter rapidly converts electricity from either the electric swing motor generator or the generator motor from AC to DC for storage in the ultra capacitor and from DC to AC to supply the swing motor or generator motor for engine assist as required.

The engine assist function of the generator motor gives the Komatsu Hybrid excavator the unique ability to provide power on demand utilising only the engine rpm required for the operation. It also enables an ultra-low idle speed of 700 rpm.

The Hybrid system is separate from the conventional excavator electrical system, it is double insulated and contains numerous in-built safety devices to protect the user and also the system from damage. It is designed to require minimal maintenance and all Hybrid components come with a special four-year 10,000 hour warranty.

Apart from the Hybrid system, Komatsu Hybrid excavators are basically the same as a conventional Komatsu excavator, offering equivalent performance in breakout force and operating speed, and are operated in precisely the same manner.

Brief specs of the new HB335-1 Hybrid excavator are as follows:

Operating weight, 35,681-36,166 kg; engine, Tier 3-compliant Komatsu SAA6D114E-5 diesel rated at 189 kW; hydraulic pump type, six-mode HydrauMind closed-centre system; maximum flow, 535 litres/min; maximum pressure, 373 bar; maximum dig depth, 7,380 mm; arm breakout, 17,400 kgf; bucket breakout, 23,100 kgf; travel position length, 11.15 m; travel position width, 3.29 m; travel position height, 3.15 m; maximum travel speed, 5.5 km/h.