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Clarifying the impact of ETBE 8% blended fuel on current Japanese gasoline vehicles, under the Japan Clean Air Program II (JCAPII) we conducted exhaust emission tests, evaporative emission tests, durability tests on the exhaust after-treatment system, cold starting tests, and material immersion tests. ETBE 17% blended fuel was also investigated as a reference. The regulated exhaust emissions (CO, HC, and NOx) didn't increase with any increase of ETBE content in the fuel. In durability tests, no noticeable increase of exhaust emission after 40,000km was observed. In evaporative emissions tests, HSL (Hot Soak Loss) and DBL (Diurnal Breathing Loss) didn't increase. In cold starting tests, duration of cranking using ETBE 8% fuel was similar to that of ETBE 0%. In the material immersion tests, no influence of ETBE on these material properties was observed.

The joint research on fuel and vehicle technology influence on emissions is being conducted in the Japan Clean Air Program (JCAP). JCAP program aims to clarify the fuel influence on emissions with the conventional and advanced vehicle technologies such as lean burn and direct injection. The gasoline working group of JCAP investigated the effect of combination of vehicle technologies and various fuel components (such as sulfur and aromatics). The program consists of two parts, Step l and Step ll. This paper describes the result of the Step I program on the Japanese 10-15 mode and 11-mode on 19 vehicles including motorcycles. An emission decrease with sulfur content reduction was confirmed by most of the test vehicles. This was more significant on the lean burn engines and direct fuel injection engines with a NOx storage-reduction type catalyst emission control system. The sulfur effect was also found for the early light off catalyst system in the cold mode (11-mode).

In spite of the efforts of related industries, the air pollution situation particularly in urban areas of Japan is not satisfactory. It has been shown that air pollution is caused mainly by increased automotive traffic and increased penetration of diesel vehicles. Air-quality problems will become much more complicated and more severe in the future with increased emphasis on reducing air pollution and global warming. These situation will require continuous reduction of automobile emissions. In order to obtain cleaner exhaust emissions, cooperative studies between vehicle and fuel technologies are considered to be essential, and AQIRP in the United States and Auto/oil Program in Europe were already conducted to develop the best combination of measures for air pollution improvement. In 1996, Japan Clean Air Program (JCAP) was launched by Petroleum Energy Center (PEC) in cooperation with the Petroleum Association of Japan (PAJ) and the Japan Automobile Manufacturers Association (JAMA).

For the better understanding of nanoparticles observed on the rode side, adding to the emission test on the chassis dynamometer and engine dynamometer test, possible factors for formation of nanoparticles are investigated. As other possible factors, cold starting of transient test cycle, blow-by gas from heavy duty diesel engine without a positive crankcase ventilation, exhaust braking, and plume mixing of vehicle exhausts were investigated. Nuclei mode particles under the transient test cycles formed during fuel cut period, fuel enrichment period and idling period. Concentration of nuclei mode particles during the idling period are depends on exhaust temperature. The higher exhaust temperature courses the lower number concentration but variation range is within twice. Emission rate of nanoparticles from blow-by gas is one thousandth of tail pipe emissions rate and was found to be negligible.

Instantaneous temperature of in-cylinder gas provides a lot of useful and local information for analyzing the combustion process in an internal combustion engine. From the standpoint of applicability to a practical engine, the infrared monochromatic radiation pyrometry required only a single optical window is considered to be more suitable comparing with the conventional infrared absorption-emission pyrometry with two optical windows. Then, the former pyrometer is used to measure the mean gas temperatures averaged on an optical path (or cylinder diameter) of a spark ignition engine connected to a prechamber with a torch nozzle of various area sizes. These measured temperature-crankangle diagrams not only clarify the influences of torch jet flow on the combustion processes, but also correspond well to the heat release rates calculated from the pressure diagrams.