International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol: 11 No: 05 19 113805-9494 IJMME-IJENS © October 2011 IJENS I J E N S Hydraulic Field Test RIG and Evaluating Plant Oil Performance WB. Wan Nik 1* , F. Zulkifli 1 , A. Ahmad 1 , O. Sulaiman 1 , S. Syahrullail 2 1 Department of Maritime Technology, Universiti Malaysia Terengganu, 21030 Terengganu, Malaysia 2 Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81300 Johor, Malaysia * niksani@umt.edu.my Abstract - Development of environmental friendly hydraulic fluid has a major influence in ecologically benign environment. This future type of oil should be non-toxic, biodegradable and ecological benign. Subsequently, it becomes crucial to recognize the sustainability of such oil in maintaining a high system performance which resulting in tremendous contribution towards machinery technology. Furthermore, the development of methods to evaluate the actual performance of hydraulic fluid has been of great interest. In this project a hydraulic test rig which incorporates LabView data acquisition system (DAQ) was built to conduct endurance test where it can be operated for up to 280 bar, running continuously with several safety features. The rig was used to test the oil and other stringent parameters, running for nearly 10000 hours at the temperature of 70 ºC under constant pressure of 70 bar and pump speed of 40 Hz. Major factors in the decrease of mechanical efficiency are thermal heat, friction, aging behaviour and contamination of the plant oil. Explained in this paper are the features of the hydraulic system built to evaluate the performance of plant oils, accompanied by some results for evaluating the suitability of the usage of plant oil as hydraulic fluid. Index Term-- hydraulic fluid, mechanical efficiency, plant oil, volumetric efficiency I. INTRODUCTION Petroleum oil is a non-renewable energy resource that has been used in wide range of important applications which include transportations and power generations. Despite of its popular use, there are efforts to produce diesel oil from the used engine oil [1], aiming to use non-petroleum oil to fuel automobiles. Majority of the researchers concentrated on the use of plant oil which commonly known as biodiesel. Some examples in the study include soy, rapeseed, palm and corn oil. Less known plants are also researched such the use of jatropha oil as an alternative fuel in diesel engine [2]. Furthermore, the research on plant oil is not limited to its use as an energy resource where it has been researched to be an alternative for traditional lubricant and hydraulic fluid, i.e. bio-lubricant and bio-hydraulic fluid. As there are evidences over the growing environmental concerns in some regions over the use of mineral-based hydraulic fluid, the plant-based hydraulic fluid is able to serve as an alternative solution to the mineral-based oil. Besides of being environmentally friendly, there are several factors that show the attractiveness of plant-based hydraulic fluid: i. Plentiful supply and relatively low cost. ii. Some plant oils offer excellent lubricating properties [3], e.g. mild antiwear/extreme-pressure. performance. iii. No adverse effects on unit performance characteristics [4]. However, it is well known that plant oils have poor low- temperature fluidity and rapid oxidation at elevated temperatures [5-7]. In addition, plant oils are limited to their naturally inherent viscosity (kinematic viscosity at 40 ºC of 30-45 cSt depending on oil type) [4]. Furthermore, plant oils also show low static friction coefficients not depending on the kinds of wet friction materials. Since hydraulic motors of a hydraulic excavator contain wet parking brakes, the most commercially available plant oils cannot provide enough brake torque capacity to park safely. Several other disadvantages of plant-based hydraulic fluid include: i. Rarely capable of providing adequate long-term performance. ii. Low oxidation resistance (can be enhanced by addition of synthetic ester). iii. Those with capable of meeting required temperature and oxidation performance is at a very premium price. Judging on the disadvantages of the plant-based hydraulic fluid and the standard requirements that need to be fulfilled, it is vital to determine the performance of the oil in a real hydraulic system. In this work, the effects from the oil degradation towards the hydraulic system efficiencies are investigated. Some of the factors, such as temperature and friction, which contribute to the degradation process, are studied by varying the pump speed and loading charge of the operation. Data obtained from the tests are used to determine the effects of speed, pressure and temperature towards the system’s volumetric, mechanical and overall efficiencies. In addition, studies on the oil viscosity and its acid value provided supporting data to the results obtained. The authors have tested the physical and chemical performance of various plant oils. The authors managed to improve the thermal and oxidation properties of the plant oils [5]. The lubrication and rheological properties of the oil have also been evaluated [7]. This is to complement the tribological investigation done in the United States and Europe [8, 9]. These tribological results are very important in order to use plant oils as other industrial fluid [10]. There are many off-the-shelf test rigs to test biodiesel running on engine that include several bench tester to test hydraulic fluid, such as to test corrosivity, viscosity,