Koji Oyama

Study of antiknock performance under various octane numbers and compression ratios in a DISI engine

This paper presents a study of antiknock performance under various octane numbers and compression ratios in a direct injection spark ignition (DISI) gasoline engine. The relationship between the octane number and engine performance in the DISI engine-the engine torque and the break specific fuel consumption (BSFC)-was investigated in comparison with a multipoint injection (MPI) engine. Due to the improvement in the charging efficiency and the advance of the ignition timing by cooled aspiration, the engine torque of the DISI engine was improved over that of the MPI engine. It was also found that the octane number requirement (ONR) was reduced. In addition, the possibility of engine performance enhancement at high compression ratios was studied. At high compression ratios, the engine torque is reduced due to the heavy knocking when low octane gasoline is used. However, an improvement in the engine torque has been observed with high octane gasoline. An increase in the ONR at a high compression ratio (15.0:1) was observed in both DISI and MPI engines, but the increase in the ONR in the DISI engine was smaller than in the MPI engine. The BSFC got worse under low-speed, high-load conditions at high compression ratios for retardation due to heavy knocking, while the BSFC was improved at low-speed, low-load and at middle speed for better thermal efficiency at high compression ratios. Finally, the benefits for fuel economy with high compression ratios and high octane gasolines were evaluated using J10-15, ECE-EUDC and LA-4 mode simulations.

Fuel-Cell Vehicle Fuels: Evaluating the Reforming Performance of Gasoline Components

Fuel cell vehicles (FCVs) are an emerging transportation technology, with a potential to provide very low vehicle emissions and significant improvements in fuel efficiency. The choice of a fuel for FCVs must consider several critical issues, including the availability of a distribution and storage infrastructure, manufacturing cost and capital requirements,energy efficiency, and performance. Gasoline, one of the candidate fuels, is noteworthy not only for its existing infrastructure, but because it has the possibility of usage for both FCVs and conventional internal combustion engines. Gasoline consists of different types of hydrocarbons, including paraffins, naphthens, olefins and aromatics - - with carbon numbers distributed over a wide range. Gasoline also contains a variety of sulfur compounds and selected additives in small amounts., In some cases gasoline also contains oxygenates such as MTBE and ethanol. To develop the optimal fuels and associated catalysts for FCVs it is necessary to understand the effects of these constituents on FCV fuel processing. Reforming performance has been evaluated with a variety of gasoline components, as well as conventional gasoline provided by refineries. Tests of initial reformer catalyst activity and durability at auto-thermal reforming (ATR) conditions have been conducted. Results showed similar reforming performance among most hydrocarbon components except aromatics. The addition of MTBE improved reforming reactivity. Both aromatics and sulfur compounds caused rapid deterioration of reforming activity, while the magnitude of the reactivity loss varied between different aromatic compounds.

Evaluation of Diesel exhaust emission of advanced emission control technologies using various Diesel fuels, and sulfur effect on performance after mileage accumulation: JCAP Diesel WG (fuel) report for step II study

To investigate the future direction of diesel emission control technologies and fuel technologies, exhaust emissions tests of diesel vehicles/engines with advanced after-treatments such as NSR catalyst, CR-DPF, and Urea-SCR or a combination of these, were conducted using various fuels, and fuel sulfur effect on performance of the after-treatments after mileage accumulation was also evaluated in step II study of JCAP Diesel WG. Overall results shows that the after-treatments have significant effects on reducing emission and reducing fuel sulfur have significant effects on function of the after-treatments in term of decrease of sulfate and SOF, and less deterioration of function of after-treatments after mileage accumulation.