• Journal of Advanced Marine Engineering and Technology
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• v.16 no.5
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• pp.85-96
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• 1992

Engine enclosures are widely adopted to reduce the noise emission in various fields of application. The radiated noise, which is due to the vibration of enclosure's outer surface, is composed of two kinds of sound power with different path of propagation. One is the 'structure-borne sound power' which stems from the engine's vibratory force applied to the structure of enclosure through the mounting parts of engine etc., while the other is the 'air-borne sound power' which is originated by the sound power radiated from the engine surface to the inner space of enclosure that should excite the vibration of enclosure from inside. In order to get a most efficient engine enclosure is required a profound consideration upon the above structure-borne and air-borne noise, since the guiding principle of countermeasure for each noise is quite different. The controlling of input vibration and its isolation are major subject for the structure-borne sound power and the specifications of absorbing member and damping panels are the major interests for the air-borne sound power. Hence it seems very efficient to separate the total sound power into two categories with a great accuracy when one think of further reduction of engine noise from the exciting enclosure, however, its separating methods have not been made clear for many years. Then author proposes a new practical separation method of two propagation path's contribution to the total radiation sound power for the enclosure under the engine operating condition.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.204-210
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• 2014

Experimental study was conducted to investigate the effect of EGR(exhaust gas recirculation) on engine noise using single cylinder combustion ignition engine. Under constant engine rotary speed of 1200 RPM, 8 mg fuel quantity was injected with 15, 18 and 21% of oxygen ratio and 1400 bar of injection pressure. Using the in-cylinder pressure data acquired by a piezoelectric transducer, the engine performance parameters were calculated. Radiated engine noise measured for 10 seconds was analyzed using spectral characteristics and sound quality metrics such as loudness, sharpness, roughness. From the obtained engine performance parameters and sound quality metrics, effect of oxygen ratio of the premixed air, start of injection timing on frequency characteristic and sound quality metrics were analyzed. Correlation analysis was conducted between MPRR(maximum pressure rise rate), RI(ringing intensity) and sound quality metrics. RI was identified as the most important factor having influence on the sound quality metrics.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.195-202
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• 2016

In this study, a concept of active sound enrichment (ASE) control system was implemented and demonstrated for improving engine sound quality inside the cabin of a passenger car during acceleration. Unlike the active noise control cancels the noise for disturbance rejection, the ASE adds additional sound to the noise for tracking control. This approach requires a new algorithm to provide additional artificial sound to the original engine sound using active control strategy to achieve a target sound profile, which is predefined to satisfy required interior sound quality. The ASE algorithm was implemented in a digital controller dSPACE DS1401 and real-time control experiment was accomplished in an actual car. The ASE control results show that the actively enriched sound of each engine order against RPM tracks the target profiles precisely and quickly and improves the discontinuity, the level ratios and the sound pressure level of each engine order. Thus it is anticipated the ASE system can be applied for the improvement of the engine sound quality inside the cabin during acceleration.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.12
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• pp.1639-1644
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• 2018

Unlike internal combustion engines, electric cars have little engine sound and very quiet, causing the following problems to occur. First of all, pedestrians are a threat to safety because they can't feel the car approaching. The driver is also unable to recognize how fast his car is driving at a certain speed. To solve these problems, electric cars should be artificially created and reused. This paper examines the problems of the Sampling engine sound currently being used and uses the engine sound to produce a sound engine sound for the solution. The sampling engine sound has some limitations in making natural engine sounds. To overcome this problem, we studied two methods of using software synthesizers. They found subtractive synthsizing and wavetable synthsizing, which compared wavetabe synthsizing with actual engine, sampling and subtractive methods to find the most similar to real engine sound. We found that data usage and production cost are more advantageous than sampling method and subtractive syndication method.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.571-577
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• 2021

This study is a study on System On Chip (SOC) that implements virtual engine sound in electric vehicles without engines, and realizes vivid engine sound by combining Adaptive Difference PCM (ADPCM) method and frequency modulation method for satisfaction of driver's needs and safety of pedestrians. In addition, by proposing an electronic sound synthesis algorithm applying Musical Instrument Didital Interface (MIDI), an engine sound synthesis method and a constitutive model of an engine sound generation system are presented. In order to satisfy both drivers and pedestrians, this study uses Controller Area Network (CAN) communication to receive information such as Revolution Per Minute (RPM), vehicle speed, accelerator pedal depressed amount, torque, etc., transmitted according to the driver's driving habits, and then modulates the frequency according to the appropriate preset parameters We implemented an interaction algorithm that accurately reflects the intention of the system and driver by using interpolation for the system, ADPCM algorithm for reducing the amount of information, and MIDI format information for making engine sound easier.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.10
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• pp.883-889
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• 2011

The brand sound of vehicle diesel engine is recently one of the important advantage strategies in the automotive company. Because various noise components masked under high frequency level can be audible in quieter driving situation. Many researches have been carried out for subjective and objective assessments on vehicle sounds and noises. In particular, the interior sound quality has been one of research fields that can give high quality feature to vehicle products. Vehicle interior noise above 500 Hz is usually controlled by sound package parts. The materials and geometries of sound package parts directly affect on this high frequency noise. This paper describes the sound quality evaluation method for the vehicle diesel engine noise to establish objective criteria for sound quality assessment. Considering the sensitivity of human hearing to impulsive sounds such as diesel noise, the human auditory mechanism was simulated by introducing temporal masking in the time domain. Furthermore, each of the human auditory organs was simulated by computer codes, providing reasonable analytical explanations of typical human hearing responses to diesel noise. This method finally provides the sound quality index of vehicle diesel engine noise that includes high frequency intermittent offensive sounds caused by impacting excitations of combustion and piston slap.

• Journal of Power System Engineering
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• v.3 no.3
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• pp.97-103
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• 1999

As the noise of ship engine room is too loud, the engineer who works in a ship engine-room has the trouble of hearing. In this paper deals the investigation of the noise of ship engine room and cabins with the internationally allowable noise exposure level and noise exposure time. Recently, the problem of engine-room noise is more serious because of shipowner wants to make small number and larger size of cylinder. Therefore, engineers work in a ship engine-room for a long time have the trouble of hearing when they are exposed the high noise level. In this study, two kinds of vessels were used to investigate the noise of engine room, engine-control room, bridge, offices and cabins. As criteria of sound levels, A-weighted sound pressure level and octave band pressure level were used.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.435-438
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• 2005

In this paper, we implemented a system that is called sound engine in musical synthesizer and synthesized a sound of Gayageum using TMS320C6713 DSK. Sound engine consists of two parts: synthesis algorithm and processor. We improved physical modeling using digital waveguide as a synthesis algorithm and we used TMS320C6713 as a processor. The excitation signals that make timbre are stored in memory. When we input parameters, sound engine synthesizes sound of Gayageum. The experimental result shows that synthesized sounds are very similar to real sounds.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.37-41
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• 2017

In the development of means of transportation, human beings who walk, ride or ride carriages are now enjoying the benefits of many means of transportation, including bicycles, airplanes, trains, buses, and cars. In the case of automobiles among various means of transportation, there is an advantage that an individual can conveniently move while possessing it. To solve air polution problems at the same time, eco-friendly automobiles such as low-noise, low-pollution, and high-efficiency automobiles have emerged. However, in the case of eco-friendly vehicleJ, engine noise at low speeds is a noise that is unlike existing vehicles and poses a threat to the safety of pedestrians. In this study, virtual engine system has been developed to prevent engine accidents caused by low- The pedestrians are aware of the fact that the vehicle is approaching.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.208-209
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• 2012

This paper describes a comprehensive process and range of design tools and components for providing Improved perception of engine sound for mass production vehicles by the generation of finely tuned engine harmonics.