Aizoh Kubo

Palm oil and mineral oil based lubricants-their tribological and emission performance

A comparative study of wear, friction, viscosity, lubricant degradation and exhaust emissions was carried out on a palm oil and a mineral oil-based commercial lubricating oil. The wear and friction test was at first conducted using a reciprocating universal wear machine followed by a two-stroke gasoline Yamaha portable generator set, ET 950. The test conditions for the bench test were: pressure, 3.0 MPa; sliding speed, 0.20 m s−1; sliding stroke, 80 mm; room temperature, ≅25°C. The test conditions for the actual engine were: constant load, 0.4 kW for wear of the piston ring but various loads for exhaust emissions and constant speed, 2800 rpm. Analysis of post bench test lubricating oils was performed using ISL viscometer, TAN/TBN analyzer and FT-IR spectroscopy to investigate viscosity, TAN value and the oxidation level, respectively. Exhaust emission analysis was also performed using a BOSCH exhaust gas analyzer. Experimental results demonstrated that the palm oil based lubricating oil exhibited better performance in terms of wears, and that the mineral oil based lubricating oil exhibited better performance in terms of friction. However, the palm oil based lubricant was the more effective in reducing the emmission levels of CO and hydrocarbon.

Performance, emissions and wear characteristics of an indirect injection diesel engine using coconut oil blended fuel

Abstract Dynamometer tests have been carried out to evaluate the performance, emissions and wear characteristics of an indirect injection diesel engine when fuelled by 10, 20, 30, 40 and 50 per cent blends of ordinary coconut oil (COCO) with ordinary diesel fuel (OD). The test was conducted for 100 h using each of the test fuels to monitor the effect of COCO blends on the wear and lubricating oil performance. OD fuel was also used for comparison purposes. The operating performance of the engine and the emission characteristics of exhaust gases were compared. The effect of blended fuel on the engins wear and lubrication characteristics in terms of wear metal (Fe), water concentration, oxidation, viscosity, total base number and additive depletion was analysed. The performance and emissions characteristics results showed that 10-30 per cent coconut oil blends produced slightly higher performance in terms of brake power than OD. All the COCO blends produced lower exhaust emissions including polycyclic aromatic hydrocarbons and particulate matter. The wear and lubrication oil characteristics results showed that COCO blends up to 30 per cent produced similar results to OD. This programme will give useful information for further research and development in the future if COCO is used as an alternative to OD.

Identification of the Machine Settings of Real Hypoid Gear Tooth Surfaces

In the spiral bevel and hypoid gear manufacturing industry, master gear sets are usually developed from initial machine settings obtained from computer software or instruction sheets. These initial machine settings are then modified until a satisfactory bearing pattern is obtained, a process called bearing pattern development. Once a satisfactory bearing pattern is obtained, manufacturing errors and heat treatment distorsions can be accounted for by proportionally changing the machine settings according to the results of a V-H test in which the pinion vertical and horizontal positions are modified until the bearing pattern is acceptable. Once a satisfactory combination of master pinion and gear is obtained, their actual tooth surfaces usually do not correspond to those of the initial theoretical model, and the theoretical pinion and gear surface definitions are unknown. This paper presents a computer algorithm used to identity the machine settings producing a theoretical tooth surface closest to that of a measured surface, what the authors call Surface Match, in order to effectively simulate the kinematical behavior of real gear teeth. The approach is applicable to both 1st and 2nd order surface errors, including profile deviation, for any cutting process. However, given the availability of experimental data for the Fixed Setting TM , Formate Tm and Helixform TM cutting processes, the examples presented in the paper are related to these cutting processes.

Design of laser interferometric measuring device of involute profile

The vibration and noise of gears is one of the serious problems for devices, such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are considerably affected by the tooth flank form deviation of micrometer order. The quality of product gears is controlled using a gear measuring instrument and calibrated with an involute artifact. However, the conventional calibration of the involute artifact cannot achieve a sufficient accuracy. In this report, a direct method of measuring the involute artifact using a laser interferometer is proposed. Fundamental experiments are carried out, in which the effects of the surface condition of the measured object and the effect of the driving of the artifact are investigated. It is confirmed that the proposed method enables the measurement of the detailed form of an involute tooth flank and has the potential of accomplishing a highly precise measurement of an involute artifact.

Simulation method for interference fringe patterns in measuring gear tooth flanks by laser interferometry

We present a ray-tracing-based method for simulation of interference fringe patterns (IFPs) for measuring gear tooth flanks with a two-path interferometer. This simulation method involves two steps. In the first step, the profile of an IFP is achieved by means of ray tracing within the object path of the interferometer. In the second step, the profile of an IFP is filled with interference fringes, according to a set of functions from an optical path length to a fringe gray level. To examine the correctness of this simulation method, simulations are performed for two spur involute gears, and the simulated IFPs are verified by experiments using the actual two-path interferometer built on an optical platform.

Analysis of General Characteristics of Transmission Error of Gears With Convex Modification of Tooth Flank Form Considering Elastic Deformation Under Load

The vibrationlnoise of power transmission gears is a serious problem for vehicles including automobiles, and therefore many studies on gear vibration have been reported. These studies, however, were carried out by investigation using numerical simulations in which gears with specific dimensions and tooth flank modifications under specific loading were considered. Therefore, the general characteristics of the transmission error of gears have not been clarified theoretically. In this report, a general model for the tooth meshing of gears is proposed; in which a quasi-infinite elastic model composed of springs with stiffness peculiar to the gear is incorporated. The transmission error of gears is formulated by theoretical equations. An investigation on the factors affecting the general characteristics of transmission error is accomplished using the formulated equations. The qualitative characteristic of the transmission error of gears with convex tooth flank form deviation is determined by the actual contact ratio and qualitative elements of gears, i.e., tooth flank form deviation and the distribution of stiffness. Even if the amplitude of torque, the amount of tooth flank form deviation, and other quantitative elements are not determined, the qualitative characteristic of transmission error can be derived. The peak-to-peak value of transmission error increases proportionately to the amount of tooth flank form deviation.

Gear checker analysis and evaluation using a virtual gear checker

The vibration of gears is one of the serious problems for machines. The characteristics of vibration of gears are considerably affected by the tooth flank form deviation of micrometer order; therefore, strict quality control of the tooth flank form is required. However, because the gear checker (a gear-measuring machine) is structurally complex, it is difficult to analyze how the error factors of the gear checkers affect the measurement result. In this research, a virtual gear checker (VGC) is proposed, that is, a computer program that considers the structures, motions and possible error factors of the real gear checkers, such as motion error. The VGC can be used to simulate the gear measurement, and the effects of the error factors on the measurement result can be analyzed. It is possible to evaluate the uncertainty of tooth flank measurement much more easily and quickly with a VGC than with a real gear checker. A VGC can be used to analyze not only the gear measurement but also arbitrary-shaped objects such as a ball artefact, and the theoretical measurement result is output from the VGC. In this paper, we describe the development of a VGC, and the effect of error factors and the uncertainties of gear measurement are analyzed.

Evaluation method of lead measurement accuracy of gears using a wedge artefact

The reduction of the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometre order; therefore, a strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a master gear or a lead master. However, it is difficult to manufacture masters with high accuracy because the helix is a complicated geometrical form. In this paper, we propose a method of evaluating a gear-measuring instrument using a wedge artefact, which includes a highly precise plane surface. The concept of the wedge artefact is described and a mathematical model of the measuring condition of the wedge artefact is constructed. Theoretical measurement results for the wedge artefact are calculated. The wedge artefact is designed and produced on the basis of the theoretical measurement results. A measurement experiment using the wedge artefact is carried out and its effectiveness is verified.

Design Method of Double Ball Artifact for Use in Evaluating the Accuracy of a Gear-Measuring Instrument

Vibration of gears is a serious problem in mechanical devices. The characteristics of these vibrations are strongly affected by tooth flank form deviation of micrometer or submicrometer order. The quality of manufactured gears is controlled by a gear-measuring instrument. The accuracy of the profile measurement by such an instrument is evaluated using a master gear or an involute artifact. However, it is difficult to manufacture gears with high accuracy because the involute is a complicated geometrical form. To solve this problem, the double ball artifact (DBA) has been proposed as a means to evaluate the profile measurement accuracy. The application of the DBA requires a DBA design method so that the DBA can be applied to a wide variety of gear dimensions in the industrial field and can realize high-precision evaluation. In the present study, a design method is proposed for the DBA, and the dimensions, tolerance, and material of the DBA are determined. A DBA is designed and manufactured according to the proposed design method and the effectiveness of the manufactured DBA is verified experimentally using a gear-measuring instrument.

Artifact Design and Measurement Error Analysis in the Evaluation of Lead Measurement Accuracy of Helical Gear Using Wedge Artifact

The reduction in the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometer order; therefore, strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a helicoid artifact. However, it is difficult to manufacture it with high accuracy because the helix is a complicated geometrical form. To solve this problem, a method of evaluating a gear-measuring instrument using a wedge artifact, which includes a highly precise plane surface, has been proposed. In this research, to put the wedge artifact into practice, a design method of the wedge artifact is developed. In addition, the effects of the measuring condition and the setting error of the wedge artifact on the measurement result are investigated. The uncertainty for the evaluation method using a wedge artifact is assessed by a measurement experiment and simulation.