Experiences gained from the testing of biodiesel fuels in Hong Kong

Abstract

Biodiesel is one of the fast growing alternative fuels for diesel engines in the world with yearly consumption exceeds 300 million gallon. In 2000, the Hong Kong SAR Government has commissioned the University of Hong Kong to conduct a comprehensive evaluation on the performance of biodiesel on in-service diesel-powered vehicles in Hong Kong and to compare the results with those using ultra low sulphur diesel (50 ppm sulphur) currently used in Hong Kong. Three types of biodiesel fuels were tested with different biodiesel/ULSD blending ratios. The whole study comprised of two parts, namely, a chassis dynamometer exhaust emission test (NOx, CO and HC1) and a diesel lug down test for each of the vehicle tested. The result of the test is positive and confirms the environmental benefit of using biodiesel fuel. However, a very slight increased in NOx concentration is reported. During the course of the study, some issues related to the durability and fuel hoses compatibility have been raised that may affect the road worthiness of vehicles. In order to assess the compatibility of the rubber fuel hoses with biodiesel, a fuel hose compatibility test was performed to study the characteristics of fuel hoses subjected to fuels with different biodiesel percentages and with different durations. Result of the test leads to some recommendations on the use of special fuel hoses for biodiesel fuel. A one-year durability test on three vehicles using biodiesel was carried out to observe the long term effect of biodiesel on vehicles.