• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.71-76
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• 2014

This Research focuses on how to maximize fuel economy improvement of I.S.G. while keeping 12V system. With 12V system the maximum gain of fuel economy with I.S.G. is known to be about 3~5% in FTP-75 mode because engine stop is only conducted in standstill idle. But in this study deceleration engine stop (engine speed is zero) has been tried additionally and the optimum condition for deceleration engine stop was found to maximize fuel economy improvement in practical point of view, the result of which is about 8.8% in FTP-75.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.42-49
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• 2014

The gasoline direct injection (GDI) system is considerably spreading in automotive market due to its advantages. Nevertheless, since GDI system emit higher particle matter (PM) due to its combustion characteristics, it is difficult to meet strengthened emission regulation in near future. For this reason, a combined GDI with MPI system, so-called, dual injection (DUI) system is being investigated as a supplemental measure for the GDI system. This paper focused on power and fuel consumption effect by injection mode strategy of DUI system in part load and idle engine operating condition. In this study, port fuel injectors are installed on 2.4 liters GDI production engine in order to realize DUI system. And, at each injection mode, DOE (design of experiment) method is used to optimize engine control parameters such as dual injection ratio, start of injection timing, end of injection timing, CAM position and so on. As a consequence, DUI mode shows slightly better or equivalent fuel efficiency compared to conventional GDI engine on 9 points fuel economy mode as well as MPI mode shows less fuel consumption than GDI mode during idle operation. Furthermore, DUI system shows improvement potential of maximum 2.0% fuel consumption and 1.1% performance compared to GDI system in WOT operating condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.51-56
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• 1998

This paper presents modal contribution method to reduce vehicle vibration. Normal mode analysis is performed to obtain modal vector matrix. The proposed method uses this modal vector matrix to evaluate forced response of an active mode to the applied engine forces and the rotating force due to wheel unbalance mass. Comparing the responses, of the specific active mode with one another, it can be easily done to determine most contributed mode in the interesting frequency band. Then we can find dominant bushes by the strain energy distribution of the mode. Vibration response is decrease with modification of those bushes.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.537-544
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• 2015

The effects of the modification of hybrid vehicle components on diesel exhaust emissions were investigated in this study. We examined the changes in exhaust emissions and the fuel consumption (FC) caused by the modification of generator (alternator) and motors. Exhaust emissions such as black carbon (BC), HC, $NO_X$ and $CO_2$ were measured not only in idle state but also on an actual urban road as well as on a chassis dynamometer. BC, $NO_X$ and HC emissions increased by 95%, 27% and 34% respectively when the generator charged the battery in the idle condition. BC and FC decreased in hybrid mode on the actual urban road partly because the motors were used to assist the diesel engine. In addition, the decreases in exhaust emissions and FC were also evident in the hybrid mode when the vehicle was tested on the chassis dynamometer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7A
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• pp.710-719
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• 2008

In this paper, a transmission technique of paging indicator (PI) on the existing preamble is proposed to reduce power consumption of the user equipment in idle mode for OFDM-based cellular systems. Compared with the PI transmission technique using the L1/L2 control channel, the PI transmission technique using preamble has advantages of not requiring additional overhead for PI transmission as well as reducing computational complexity for PI detection. Synchronization and PI detection techniques are descried for OFDM-based cellular systems, especially for mobile WiMAX systems. It is shown by computer simulation that the PI can be transmitted using the preamble (or common synch symbol) without affecting performances of synchronization and cell searching in mobile WiMAX systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1601-1606
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• 2005

In this study, an automatic idle stop control system was developed, which automatically stops the idle state engine as it detects the stop state of the car for several seconds and restarts the stopped engine with the driver's electrical signal. It is composed of microprocessor and the related electronic circuits and communicates with ECU and TCU. With accurate and confirmed operating performance, the control system was equipped in the test car which was proceeded the ECE15+EUDC mode test. It is confirmed that the control system, ASG has much favourable effects on reducing the fuel consumption and harmful exhaust emissions.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.4
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• pp.568-576
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• 2017

This paper presents a clock and data recovery circuit with an adaptive loop bandwidth calibration scheme and the idle power saved frequency acquisition. The loop bandwidth calibration adaptively controls injection currents of the main loop with a trimmable bandgap reference circuit and trains the VCO to operate in the linear frequency control range. For stand-by power reduction of the phase detector, a clock gating circuit blocks 8-phase clock signals from the VCO and cuts off the current paths of current mode D-flip flops and latches during the frequency acquisition. 77.96% reduction has been accomplished in idle power consumption of the phase detector. In the jitter experiment, the proposed scheme reduces the jitter tolerance variation from 0.45-UI to 0.2-UI at 1-MHz as compared with the conventional circuit.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.110-113
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• 2006

This paper describes the development process of body and full vehicle for reduced idle vibration through the data level of frequency and sensitivity. The vibration mode map is used to separate body structure modes from resonance of engine idle nm and steering system. This paper describes the analysis approach process to reduce the variation of uncertainties for idle vibration performance at initial design stage. The robust design method is performed to increase the stabilization performance under vehicle vibration. It is used to predict the effects of the stiffness deviation according to the spot welding condition of the body structure. The tolerance associated with hood over slam bumper is analyzed for the quality deviation of the moving system in full vehicle. And the glass sealant stiffness and weight difference is considered for the deviation characteristic. The design guideline is suggested considering sensitivity about body and full vehicle by using mother car at initial design stage. It makes possible to design the good NVH performance and save vehicles to be used in tests. These improvements can lead to shortening the time needed to develop better vehicles.

• Journal of KSNVE
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• v.7 no.4
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• pp.681-688
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• 1997

The purpose of engine mount system is to reduce the noise and vibration caused by engine vibration, and to decouple the roll and bounce mode at idle. To reduce the noise and vibration level in a vehicle, it is important to make the design optimization of engine mount system that consider the moment of inertia and inclination of mount rubber. As a result, according to the definition of Torque Roll Axis (TRA), the vibration axis at idle must be on the TRA or very close to it. In this paper, we studied the effect of the design optimization of engine mount system. And we have achieved good improvements in noise and vibration quality of F.R. vehicle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.330-337
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• 1996

The purpose of engine mount system is to reduce the noise and vibration caused by engine vibration, and to decouple the roll and bounce mode at idle. To reduce the noise and vibration level in a vehicle, it is important to make the design optimization of engine mount system that considered the moment of inertia and inclination of mount rubber. As a result, according to the definition of Torque Rool Axis (TRA), the vibration axis at idle must be on the TRA or very close to it. In this paper, we studied the effect of the design optimization of engine mount system. And we have a good NVH performance.