No abstract

Abstract:The variations in diesel engine idle vibration caused by fuels of di erent composition and their contributions to the variations in steering wheel vibrations were assessed. The time-varying covariance method ( TV-AutoCov) and time-frequency continuous wavelet transform (CWT ) techniques were used to obtain the cyclic and instantaneous characteristics of the vibration data acquired from two turbocharged four-cylinder, four-stroke diesel engine vehicles at idle under 12 di erent fuel conditions. The analysis revealed that TV-AutoCov analysis was the most e ective for detecting changes in cycle-to-cycle combustion energy (22.61 per cent), whereas changes in the instantaneous values of the combustion peaks were best measured using the CWT method (2.47 per cent). On the other hand, both methods showed that diesel idle vibration was more a ected by amplitude modulation (12.54 per cent) than frequency modulation (4.46 per cent). The results of this work suggest the use of amplitude modulated signals for studying the human subjective response to diesel idle vibration at the steering wheel in passenger cars.

Cultural and creative industries have become prosperous, and successful examples in the UK have inspired many countries to commercialise their own cultures by integrating their cultural values into art and design production. Inspired by this trend, the aim of this project is to increase awareness of traditional Chinese cultural aesthetics in modern product development as well as to highlight the role of cultural sensitivity in the product design process. This study focuses on industrial cultural products and examines the meanings and values of cultural products. Through the examination of the user experience of current cultural products with questionnaires and interviews with product designers, a design toolkit for Chinese cultural products was developed and applied in design practice. Design majors from various cultural backgrounds were recruited to participate in workshops to evaluate the usability of the toolkit and to validate whether the toolkit helped in their design processes. The findings of the research revealed that users' experiences, particularly users' emotional engagement with the products, could be enriched when the design toolkit was applied in the design process. This design toolkit is designed for use by international designers in the initial stage of the design process when idea generation, brainstorming and sketching occur. The toolkit could be applied not only in product design but also in visual communication design, interior design and digital content design.

This study investigated the human subjective response to steering wheel vibration of the type caused by a four-cylinder diesel engine idle in passenger cars. Vibrotactile perception was assessed using sinusoidal amplitude-modulated vibratory stimuli of constant energy level (r.m.s. acceleration, 0.41 m/s(2)) having a carrier frequency of 26 Hz (i.e. engine firing frequency) and modulation frequency of 6.5 Hz (half-order engine harmonic). Evaluations of seven levels of modulation depth parameter m (0.0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0) were performed in order to define the growth function of human perceived disturbance as a function of amplitude modulation depth. Two semantic descriptors were used (unpleasantness and roughness) and two test methods (the Thurstone paired-comparison method and the Borg CR-10 direct evaluation scale) for a total of four tests. Each test was performed using an independent group of 25 individuals. The results suggest that there is a critical value of modulation depth m = 0.2 below which human subjects do not perceive differences in amplitude modulation and above which the stimulus-response relationship increases monotonically with a power function. The Stevens power exponents suggest that the perceived unpleasantness is non-linearly dependent on modulation depth m with an exponent greater than 1 and that the perceived roughness is dependent with an exponent close to unity

No abstract