TRIAS: harnessing hydraulics to reduce fuel consumption

To help contractors be more profitable in their activities, and to reduce their environmental impact, equipment manufacturers are striving to produce machines capable of less fuel consumption. While some have reduced the engine output of their machines, Hitachi has taken a different approach with its unique TRIAS hydraulic system. The aim was to ensure that its equipment could do as much as possible with as little fuel as possible.

Innovative evolution

The name ‘TRIAS’ refers to the three-pump hydraulic system that replaced the previous two-pump system for this size of excavator. The third pump helps to maximise efficiency and productivity – without sacrificing fuel economy – by reducing the loss of hydraulic pressure.

The key to TRIAS is the combination of the three-pump system, control valve, multiple pressure sensors and computer-controlled solenoid valves. Tuning the system is vital for efficiency of the control valve – and this Hitachi technology is unique to the construction industry.

The original TRIAS system was developed for the Zaxis-5 medium excavator range in 2011. To explain how a TRIAS I (and conventional) control valve spool works, there is always a significant return of pressurised oil to the tank during the operation of a function, especially at small and medium control lever strokes. This flow of pressurised oil to the tank results in hydraulic power loss.

In 2015, Hitachi launched TRIAS II in its Zaxis-6 range of medium excavators. This system further fine-tuned the control valve spools and added additional pump flow limit solenoid valves. This further reduced hydraulic losses in the control valve.

In 2020, TRIAS III was unveiled with the arrival of the Zaxis-7 range. This system benefits from further fine-tuning of the control valve spools and new features resulting in even less hydraulic losses, greater efficiency and controllability.

One such feature is the pump 3 minimum angle fix control. If the pump pressure becomes high during digging, pump 3 is fixed to a no-load/minimum flow rate and pumps 1 and 2 are used at high pressure and maximum flow rate. This improves pump efficiency by 2%, reducing fuel consumption.

Further enhancing profitability

The evolution of the TRIAS system has achieved impressive fuel consumption reductions. The initial TRIAS I and subsequent II and III versions have delivered a total reduction of 26% in the 25-tonne excavator class (see diagram above). This has resulted in significant TCO savings and vital emission reductions to comply with stringent environmental regulations.

In addition, the TRIAS system ensures an efficient swing operation and an exceptionally fast front attachment speed. This, coupled with high levels of control and precision, assisted by the operator’s ability to fine-tune the machine by adjusting settings on the monitor menu, contributes to excellent productivity and further enhances profitability.

To ensure consistently high levels of performance, Hitachi has worked closely with its Nordic dealers over several years to further enhance the TRIAS system so that it meets the needs of customers.

Hitachi’s approach with TRIAS, namely to preserve the power of the machine and ensure that as much as possible can be done using as little fuel as possible, is now more important than ever with the optimum use of resources under the spotlight.

Efficiency and environmental concerns will only increase in the future, and while zero-emission electric equipment is still in the early stages of development, exceptionally fuel-efficient machines will bridge the gap.