From an ecological standpoint, our construction machinery is consistently subject to improvement in order to reduce its impact on the environment. All of our hydraulic excavators are packed with environmental concepts and a wide variety of technologies.
![[Image] Mr. Tahara is talking](/environment/showcase/speco_technique/zaxis/images/img_02-01.jpg)
Hitachi Construction Machinery's ZAXIS series hydraulic excavators feature significantly improved environmental performance. One such technological advancement can be found in the newly developed hydraulic system.
This new system speeds up the process of 'excavation', the most common application of hydraulic excavators. It enables the machines to handle significant workloads within a shorter period of time, and realizes improved fuel efficiency and reduction in CO2 emissions.
The hydraulic cylinder that activates the boom when performing excavation work can generate significant hydraulic energy. With the conventional hydraulic system, the oil that flows out of the hydraulic cylinder and simply returns to the hydraulic oil tank, which means that the generated hydraulic energy ends up being wasted. However, with the new system, the hydraulic energy accumulated on the boom side does not return to the oil tank, but instead is transmitted and utilized in the hydraulic cylinder on the arm side. With more oil flowing into the arm side, the arm can perform the same amount of work at a much faster speed.
![[Image] How the new hydraulic system works](/environment/showcase/speco_technique/zaxis/images/img_02-02.gif)
In the excavation of the earth, the arm speed was enhanced by up to 20% by fully utilizing the generated hydraulic energy. This enabled greater productivity while simultaneously reduced the environmental impact.
![[Image] Arm speed improved by up to 20%! Utilizing hydraulic energy to its full extent](/environment/showcase/speco_technique/zaxis/images/img_02-c01.gif)
![[Image] Mr. Tahara is getting on ZAXIS](/environment/showcase/speco_technique/zaxis/images/img_02-03.jpg)
![[Image] OHC4-valve engine](/environment/showcase/speco_technique/zaxis/images/img_02-04.jpg)
There are two productivity requirements that eco-friendly hydraulic excavators need to satisfy.
One is the ability to excavate large quantities of earth and sand in a short period of time, and the other is the ability to lower fuel consumption. In order to meet these two requirements, which would seem to conflict with each other, we developed a powerful and earth-friendly next-generation engine jointly with our partner engine manufacturers.
While enhancing the engine output to handle a greater workload, greater fuel efficiency was realized with an enhanced fuel control system. Needless to say, our excavators comply with the stringent emission control standards of Japan, Europe and the United States, and minimize the emission of NOx (nitrogen oxides) and PM (particulate matter), which are air pollutants.
Furthermore, the engine's work modes can be switched back and forth between the 'Power Mode (normal mode)' and the 'Fuel Saving Mode (economy mode)'. For example, power output should be given priority when the construction work needs to be completed in a short period of time, whereas fuel efficiency should be the focus when having to perform complicated tasks one step at a time. Whichever mode you choose, you can control both work efficiency and fuel efficiency in a smart way.
![[Image]Comparison
between workload and fuel consumption](/environment/showcase/speco_technique/zaxis/images/img_02-05.gif)
![[Image] The key to eco-friendly is synergies derived from proprietary technologies! The combination of the next-generation engine and new hydraulic system creates synergies, realizing both increased productivity and fuel efficiency!](/environment/showcase/speco_technique/zaxis/images/img_02-c02.gif)
The development of a next-generation engine, choices of engine work modes to maximize engine performance, and development of a new hydraulic system as described in the previous chapter that fully utilizes the hydraulic energy. These were all combined to create a synergistic effect, realizing a 12% increase in productivity in the normal mode and 13% reduction in fuel consumption in the economy mode.
Many of us walking past construction sites have probably found the sound of construction machine rather disturbing. Hitachi Construction Machinery's ZAXIS200-3 series hydraulic excavators were designed with scrupulous attention to address such issues.
![[Image] The fan to reduce the airflow noise](/environment/showcase/speco_technique/zaxis/images/img_02-06.jpg)
First, we thoroughly analyzed the sources of noise, from the engine, radiator fans, and mufflers to the hydraulic pump. The engine was improved and made stiffer to prevent the noise from spreading outside.
Repeated wind tunnel tests were conducted for the fans, and the annoying airflow noise was reduced using our unique expertise by making changes to the thickness, width, shape and angle of the curved blades. A frame that suppressed the pump's vibration as well as a noise reduction muffler were also developed.
As a result, engine noise was reduced by 5dB, fan noise by 3dB and the noise from operator's seat by 2dB, and the total noise measured around the operator's seat was reduced to 65dB, which is even quieter than a moving train or subway.
Our noise reduction system represents a significant breakthrough in the area of construction machinery unmatched in the industry.
![[Image] Example of Noise Level](/environment/showcase/speco_technique/zaxis/images/img_02-07.gif)
![[Image] To ensure ease of recycling, all resin parts are marked with the name of the material](/environment/showcase/speco_technique/zaxis/images/img_02-08.jpg)
In addition to that, easily recyclable aluminum materials are being used for parts such as radiators, oil coolers and the air-conditioning condenser, and all resin parts are marked with the name of the material used to facilitate sorted disposal.
Plant-based hydraulic oil is also available on an optional basis to power the hydraulic cylinder. Should oil accidentally leak into the soil or water, it readily breaks down into water and carbon dioxide, and causes no harm to the environment.
![[Image] A machine packed with various eco-technologies! Noise, recycling, soil contamination... Reducing all elements of environmental impact](/environment/showcase/speco_technique/zaxis/images/img_02-c03.gif)
![[Image] Plant-based oil breaks down into water and carbon dioxide](/environment/showcase/speco_technique/zaxis/images/img_02-09.gif)
Hydraulic excavators that are 97% recyclable!
![[Image] Counterweight](/environment/showcase/speco_technique/zaxis/images/img_02-10.jpg)
Hydraulic excavators are mounted with a 'counterweight' at the rear to balance the weight while performing their work.
The counterweight contains a mixture of different materials such as steel slag and sand all encased in concrete, which makes it difficult to sort these materials for reuse. To address this problem, we developed a system for collecting and recycling used counterweights, with the cost of transportation absorbed by us. This enables the counterweight to be crushed, sorted and reused.
As a result, we have achieved a total recycling rate of 97% for our hydraulic excavators.
