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To properly respond to demands to reduce national energy consumption and meet greenhouse gas emission targets based on environment policy, the Ministry of Trade, Industry, and Energy of Korea formed a research consortium consisting of government agencies and academic and research institutions to establish the first fuel efficiency standards for medium- and heavy-duty (MHD) commercial vehicles. The standards are expected to be introduced in 2017 as Phase 1 of the plan and will regulate trucks with a gross vehicle weight in excess of 3.5 tons and buses with a carrying capacity of more than 16 persons. Most MHD commercial vehicles are custom-made and manufactured in diversified small-quantity batch production systems for commercial or public use, resulting in difficulties in utilizing mandatory vehicle tests for fuel efficiency evaluations.

As a part of the global efforts to reduce CO2 emission, studies are in progress to derive regulation measures for CO2 emission from heavy-duty vehicles. Thus, identification of emission characteristics of CO2 for heavy-duty vehicle is required and test driving cycle for this would be necessary. Before developing a test driving cycle to identify the emission characteristics of CO2, selection of test subject vehicles and actual road test was carried out. Through this, road drive characteristics per diverse vehicle type and emission levels of CO2 were identified. Correlations between the currently used cycles of each country and the actual road were analyzed and the cycle most similar to the actual road situations was selected among various countries' cycles to verify whether its easy use was possible for the actual tests. The test driving cycle selected after comparison with actual road situations was modified so as to enable actual tests for all heavy-duty vehicles.

Studies of driving cycles for buses have been published in a number of papers, e.g., the Central Business District (CBD) and New York Bus (NY Bus) driving cycles. Such studies, however, cannot represent the actual driving environment of Seoul because of differences in road conditions and the volume of traffic. Thus, this study presents the development of a driving cycle for the city bus system of Seoul, the capital city of Korea. A representative route is selected by means of a statistical analysis of the city bus routes in Seoul. Experiments are performed to measure velocity, road grade, engine speed, load conditions, gear-shift patterns, and vehicle acceleration in actual Seoul traffic. A simulation model is developed to evaluate a driving cycle on the basis of the measured data obtained. The coupling effect between velocity and acceleration is analyzed, as well as the coupling effect between road grade and vehicle acceleration.

This paper presents a technique for the improvement of the idle stability on a spark ignition engine through the adaptive control of the individual cylinder ignition timing. In many causes that affect the idle stability, the difference in the torque production between cylinders has been a matter of concern. The engine speed has been sampled 220 times per a cycle and the average angular acceleration has been calculated from it. In this research, the average angular acceleration has been characterized by nonuniform torque production among cylinders. The control system has been designed to keep the average angular acceleration constant.