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Low NOx and soot free premixed diesel combustion can be realized by increasing ignition delays in low oxygen atmospheres, as well as the combustion here also depends on fuel ignitability. In this report single intermittent spray combustion with primary reference fuels and a normal heptane-toluene blend fuel under several oxygen concentrations in a constant volume combustion vessel was analyzed with high-speed color video and pressure data. Temperature and KL factor distributions are displayed with a 2-D two-color method. The results show that premixing is promoted with a decrease in oxygen concentration, and the local high temperature regions, above 2200 K, as well as the duration of their appearance decreases with the oxygen concentration. With normal heptane, mild premixed diesel combustion can be realized at 15 vol% oxygen and there is little luminous flame.

The study of 10% ethanol blended gasoline (E10 gasoline) utilization has been conducted in the Japan Auto-Oil Program (JATOP). In order to clarify the impact of E10 gasoline on vehicle performances, exhaust emissions, evaporative emissions, driveability and material compatibility have been investigated by using domestic gasoline vehicles including mini motor vehicles which are particular to Japan. The test results reveal that E10 gasoline has no impact on exhaust emissions, engine startup time and acceleration period under the hot start condition, but a slight deterioration is observed in some test cases under the cold start condition using E10 gasolines with 50% distillation temperature (T50) level set to the upper limit of Japanese Industrial Standards (JIS) K 2202. Regarding evaporative emissions, the tested vehicles shows no remarkable increase in the hot soak loss (HSL), diurnal breathing loss (DBL) and running loss (RL) testing with E10 gasolines.

The effects of ethyl tertiary butyl ether (ETBE) and ethanol (EtOH) blending in gasoline on particulate matter (PM) emissions were investigated for a direct-injection spark ignition vehicle running on a chassis dynamometer. The test was performed under constant-speed conditions and 10.15-mode and 11-mode cycles. The total number of particles was measured by using a condensation particle counter (CPC). It was observed that the number of particles was affected by the amount of aromatics in the fuel and T90 (the distillation temperature where 90 vol.% of the fuel is evaporated), which was caused by the blending of the oxygenated compounds. The impact of T90 on the number of particles was greater for the 11-mode cycle than for the 10.15-mode one.