• KSTLE International Journal
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• v.2 no.2
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• pp.120-126
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• 2001

Performance requirements for automatic transmission fluids have been changed reflecting the design changes of automatic transmissions. The major purpose of these design changes is concentrated upon improvements of both fuel economy and drivability. In order to formulate such high performance ATFs as satisfy those requirements, it is necessary to use high quality base oils like VHVI base oils and PAOs. In this study, the effect of base oils characteristics on ATF performance is investigated, mainly regarding differences in frictional characteristics with deterioration. Frictional characteristics are determined using the SAE No. 2 machine and ATFs are deteriorated under various controlled conditions. Moreover low-temperature fluidity, oxidation stability, and seal compatibility are also compared for four different ATFs. From the investigation, it was found that the use of Group III and IV base oils in ATFs gives several benefits with respect to low temperature viscosity, oxidation stability and SAE No.2 friction characteristics.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.2
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• pp.69-78
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• 2013

As vehicles become more intelligent for safety and convenience of drivers, in-vehicle networking systems such as controller are network (CAN) have been widely used due to increasing number of electronic control unit (ECU). Recently, FlexRay was developed to replace CAN protocol in chassis networking systems, to remedy the shortage of transmission capacity and unsatisfactory real-time transmission delay of conventional CAN. However, it is difficult for vehicle network designers to calculate platform configuration registers (PCR) and determine a base cycle or slot length of FlexRay. To assist vehicle network designers for designing FlexRay cluster, this paper presents automatic field bus exchange format (FIBEX) generation algorithm from CANdb information, which is de-facto standard database format for CAN. To design this program, structures of FIBEX, CANdb and relationship among PCR variables are analyzed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.117-122
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• 2004

In order to improve the fuel economy by design change of automatic transmission, various technologies such as increased shift stages, slip control of lock-up clutch and compact and low-weight design have been developed. And also many OEMs have developed their own ATFs as a part of these automatic transmissions. In this study. to investigate the effects of ATF characteristics on fuel economy, we got the worldwide OEM ATFs and made some reference fluids. And physical properties, frictional characteristics and fuel economy using dynamometer test for these fluids were evaluated. From the investigation, it was found that viscosities of ATFs are correlated with fuel economy in dynamometer test and reducing the viscosities made it possible to obtain fuel economy.

• Proceedings of the KIEE Conference
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• 2005.10a
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• pp.197-201
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• 2005

In this paper, an automatic welding carriage is developed by wireless communication. In the developed system, a data transmission of a automatic welding line tracking is adopted by RF communication. Additional, a welding condition of the automatic welding carriage IS displayed by microprocessor. Therefore, the developed system can overcome the restriction of an operating distance and perform an accurate transmission of the control signal.

• Tribology and Lubricants
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• v.21 no.3
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• pp.142-148
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• 2005

In order to improve the fuel economy by design change of automatic transmission, various technologies such as increased shift stages, slip control of lock-up clutch and compact and low-weight design have been developed. And also many OEMs have developed their own ATFs as a part of these automatic transmissions. In this study, to investigate the effects of ATF characteristics on fuel economy, we got the worldwide OEM ATFs and made some reference fluids. And physical properties, frictional characteristics and fuel economy using dynamometer test for these fluids were evaluated. From the investigation, it was found that viscosities of ATFs are correlated with fuel economy in dynamometer test and reducing the viscosities made it possible to obtain fuel economy.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.135-146
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• 2016

This study investigated the effect of the changes in metal characteristics due to the hot forging on SCR420HB applied to ensure the optimal production of the hot-forging ratio on the mechanical properties of an automotive automatic transmission gear. The microstructural changes in the forging ratio were investigated by adjusting the forging range into multiple ranges from alloy steel. This was done in order to set the optimum forging range given the manufacturing process conditions during the hot forging of alloy steel parts with a carbon content of more than 0.8% wt. The effects of the content change in the microstructure on the mechanical properties due to the use of the part were examined.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.7
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• pp.561-568
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• 2008

The quality of the automatic transmission shift for a wheel loader has been generally evaluated by driver's perception. However the subjective evaluation of the drivers is not always directly related to the shift quality. It is necessary to set up the method for an objective assessment of the shift quality. In this paper, a quantitative assessment method has been developed for the shift quality of the automatic transmission in a wheel loader. The indices for the evaluation were selected through the various tests like the acceleration and the turbine rpm as well as the subjective evaluation of the driver, and were validated by the correlation between subjective and objective assessments using a psychophysical power law. Based on this method, the shift quality of a wheel loader has been evaluated quantitatively under various shift conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.622-626
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• 2001

Every design activity has a goal of satisfying a set of functional requirement. The commencement of a design, therefore, must have its foundation upon the identification of the functional requirements. Many of the design practices of the industrial examples can be categorized as design of small systems that are defined to have limited and fixed sets of functional requirements to be satisfied at all times. In the case of small systems it facilitates the construction of a knowledge-based system for a specific purpose to decompose the functional requirement and map ones in the lowest level into specific design features. When the number of design features is large, they need to be managed by groups. This paper suggests a grouping method for design process can be regarded as a series of selections of the predefined functional primitives according to the requirements and the preceding selections. An intelligent product design system for automatic transmission lever design is developed as an example.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.48-56
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• 2016

In this paper, we analyze the power flow of an eight-speed automatic transmission by using a lever analogy for the manufacturing of planetary gears. The results indicate that the engine power is passed down to the carrier and ring gear in the first double pinion planetary gear (DPPG1), and to the sun gear, carrier, and ring gear in DPPG3 for the first speed. Although the power flow is similar in the second speed, the power circulation occurs in the second single pinion planetary gear (SPPG2). For the third speed, the engine power is passed from the carrier to the ring gear in DPPG, at which point the power is split between the sun gears of SPPG2 and DPPG3.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.3
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• pp.13-21
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• 2007

A forklift is a motive machine powered by LPG, diesel engine or electric motors. The internal combustion engine type forklift is equipped with automatic transmission to meet the required drive load as well as the easy operation of the vehicle. This paper deals with the shift control and endurance test controller which is developed for the functional test of the newly designed automatic transmission on a dynamometer test bench. Its major function is to control the proportional solenoid currents, which is directly related to clutch pressures, for the given reference current trajectory during shift and sequential operation of shift schedule designed for the durability test at each gear. It also has the ability to monitor all the necessary test data through RS232 communication and log them to disk files. The current controller of embedded system is designed from the identified dynamics of solenoid coil and the current reference can be easily modified with a user interface software on PC so as to match the shift data by experiments.