This project focused on the test procedure of in-use vehicle noise control (for motorcycle). If the test site in urban area not fully comply with the current CNS 5799 test standard, and the local Environmental Protection Bureau needs to perform the noise test at the roadside of urban area. This project evaluates the influence of stationary noise test results carried out at various non-standard locations and applied the K2A (environmental correction factor) test to evaluate the acoustic field properties of urban test locations. Then compare the results between K2A and motorcycle’s noise test results to sum up the suggestions for result correction or further revise to improve the test procedure more appropriate for assessment of in-use motorcycle noise test. The main outlines are as follows: 1.To survey and analyze the noise test method and regulation status of in-use motor vehicle. Also, investigate the relative international noise regulations for test-site demands and correction method. 2.To investigate the effect of stationary noise of motor vehicle by measuring noise at different test-sites and sum up the relevance with environmental correction coefficient of sound field (K2A). 3.To assess the influencing factors of stationary noise results measured at the urban non-standard sites, and make recommendation for improvement of the test procedure. To organize the literature of past research and test data in the urban area, and to investigate the influencing factors of stationary noise test for recommendation of test-site demands, test procedure and data calculation process. The main conclusions are summarized in the following: 1.The reference lectures of past research in noise test procedure of motor vehicle, which evaluate the influence of sound-reflecting surfaces on a theoretical basis to explain that the close-proximity measurements setup of stationary noise were essentially unaffected by reflective surfaces in the open environment. Only if a specific frequency wave may be suffered from standing wave effect. The reproducibility and stability should be most suitable for motor vehicle testing. 2.The test-site evaluation with K2A and stationary noise of motor vehicles are compared to standard test-sites. The difference of K2A and stationary noise are less than ±1.5dB(A), the different range are fairly consistent, but the relevance trend is not clear. The results show that the influence of stationary noise tested at non-standard locations are small, and can be controlled in a specific range. As per the ISO 11201 standard, the results of K2A≦2dB showed that the non-standard urban test sites could be approximately regarded as a free-field environment. 3.By summing up all of the test results obtained at various kinds of non-standard test sites, the measurement uncertainty under 95% confidence is 1.7dB(A), and the noise difference in the test result for the standard and the non-standard sites were found to be no greater than 2dB(A) when the results were rounded according standard procedure. 4.In conclusion, measurements carried out at the non-standard locations agreed well with the corresponding test results obtained at the standard test-site. The influence is not significant. To improvement the in-use vehicle noise control, the countermeasure may either to revise the current test procedure (correct the noise test result with a fixed value for the uncertainty); or to take the uncertainty into consider while determining the penalty with current test standard.

In-use vehicle noise control, Stationary noise test, Sound power