Search Results

The adoption of electric vehicles (EVs) has been announced worldwide with the aim of reducing CO2 emissions. However, a significant increase in electricity demand by EVs might impact the stable operation of the existing power grid. Meanwhile, EV charging is acceptable to most users if it is completed by the time of the next driving event. From the viewpoint of power grid operators, flexibility for shifting the timing of EV charging would be advantageous, including making effective use of renewable energy. In this work, an EV model and simulation tool were developed to make clear how the total charging demand of all EVs in use will be influenced by future EV specifications (e.g., charge power) and installation of charging infrastructure. Among the most influential factors, EV charging behavior according to use cases and regional characteristics were statistically analyzed based on the real-world usage data of over 14, 000 EVs and incorporated in the simulation tool.

Spark plug erosion is critical in determining the overall efficiency of a spark ignition engine. Over its lifetime, a spark plug is subject to millions of firings. Each spark event results in material erosion due to several mechanisms such as melting, vaporization, sputtering and oxidation. With electrode wear, the inter-electrode spacing increases and a larger voltage difference is required to initiate the spark. The probability of engine misfires also increases with electrode erosion. Once a critical gap is reached, the energy in the ignition coil is not enough to cause a spark breakdown, and the spark plug must be replaced. Due to the long relevant time scales over which erosion occurs, and the difficulty of analyzing the spark plug environment during operation, determining spark plug lifetime typically requires extensive field testing. A high fidelity commercial thermal plasma solver, VizSpark is used simulate electrode erosion due to spark events.

Recent years, ANC (Active Noise Control) technology has been paying attention. However, rather than the noise measures, the noise gives us the impression even running sound for motorcycles. That is, the control method of the engine sound is shifted from the noise reduction to sound design in each manufactures. Therefore, we proposed a method to design the engine sound using Active Sound Quality Control (ASQC) based on the ANC. Specifically, we proposed the algorithm amplifying and reducing the engine specific order components. From the simulation results, the engine specific order components can be amplified and reduced like an equalizer with the proposed algorithm. And, auditory impressions of engine sound controlled by ASQC were investigated using psychoacoustic measurements. 13 stimuli were obtained by applying ASQC for several order components to amplify or reduce their levels.

The number of people experiencing psychological discomfort due to the increasing amount of noise emanating from motor vehicles has been on the rise. Legal regulations define the permissible level of vehicle noise in a given area. Active noise control (ANC) is a noise cancellation method that reduces low-frequency sounds, such as engine noise, effectively. Furthermore, this method is suitable for controlling engine noise because the equipment necessary to perform it is small and does not require a large space for installation. Advances in digital processing technology have increased the scope of ANC’s applications, and it is no longer restricted to use in motor vehicles. The purpose of this study is to demonstrate the effectiveness of the proposed method in reducing the motor vehicle engine noise produced during acceleration. In this study, we attempt to control the engine sounds from a vehicle with a four-cylinder four-stroke engine.

It has become clear that a motorcycle rider regards the sound and vibration which occurs from a motorcycle as a feeling of a “Kodo-kan” which is not unpleasant and becomes a part of comfortable nature. In this paper, the physical quantity relevant to a feeling of a beat was extracted from the sound and oscillating measurement data of an idling state for the purpose of quantification of the feeling evaluation of a “Kodo-kan” of the motorcycle, and the feeling evaluation score prediction of a beat was tried from the physical quantity.