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This study evaluates the influence of speciated emissions on ozone reactivity using the values of Maximum Incremental Reactivity published by the California Air Resources Board in September 1990. To evaluate the influence of fuels and vehicle specifications on speciated emissions and ozone reactivity, three different fuels (gasoline, reformulated gasoline, and methanol (M85)) were used. Hydrocarbon species were measured using three types of gas chromatographs. Aldehydes were collected in a dry cartridge and measured by High Performance Liquid Chromatograhpy (HPLC). Alcohols were collected using impingers and measured by a gas chromatograph. In the case of gasoline, as Non-methane Organic Gas (NMOG) is reduced, the proportion of speciated emissions with high ozone reactivity decreases, and this tends to lower Ozone Forming Potential (OFP). In the case of reformulated gasoline, OFP does not decrease, but Non-methane Hydrocarbons (NMHC) do as NMOG is reduced.

This paper describes Nissan's research and development work on flexible fuel vehicles. Nissan has been engaged in R&D activities for flexible fuel vehicles to examine the possibilities for long-range energy conservation and air quality improvements. The flexible fuel research vehicle described here employs an electrostatic type sensor to measure the methanol concentration in the fuel and the engine system has been designed to burn a wide variety of fuels from M85 to MO (gasoline). Test results obtained with this research vehicle indicate that OMHCE and NOx emissions with M85 are lower than with MO under a fresh catalyst condition. However, by the end of a 50,000 mile durability test, NOx emissions with M85 increase to the same level as with MO. The use of M85 as the fuel results in a pronounced increase in aldehyde emissions compared with MO.

The FFVs under study operates on either M85 or M0 or any mixture of the two. Nissan has been actively conducting reseach and development on flexible fuel vehicles (FFVs) to explore the possibilities for long-range energy conservation and air quality improvement. The engine converted for use in these FFVs is a 1.6 liter, four-cylinder in-line powerplant, with dual overhead camshafts and four valves per cylinder. It employs the Nissan Variable valve timing Control System (NVCS). The fuel sensor for measuring the methanol concentration in the fuel has been improved both in terms of accuracy and durability. This paper describes the engine performance and exhaust emission levels (formaldehydes unburned methanol and HC emissions) obtained with both M85 and M0.

Hydrocarbons and other organic materials emitted from S.I. engines cause ozone to form in the air. Since each species of organic materials has a different reactivity, exhaust components affect ozone formation in different ways. The effects of exhaust emission control devices and fuel properties on speciated emissions and ozone formation were examined by measuring speciated emissions with a gas chromatograph and a high-performance liquid chromatograph. In the case of gasoline fuels, catalyst systems with higher conversion rates such as close-coupled catalyst systems are effective in reducing alkenes and aromatics which show high reactivities to ozone formation. With deterioration of the catalyst, non-methane organic gas (NMOG) emission increases, but the specific reactivity of ozone formation tends to decrease because of the increase in alkane contents having low MIR values.

In 1994, the California Air Resources Board implemented low-emission vehicle (LEV) standards with the aim of improving urban air quality. One feature of the LEV standards is the increasingly tighter regulation of non-methane organic gases (NMOG), taking into account ozone formation, in addition to the existing control of non-methane hydrocarbons (NMHC). Hydrocarbons and other organic gases emitted by S.I. engines have been identified as a cause of atmospheric ozone formation. Since the reactivity of each chemical species in exhaust emissions differs, the effect on ozone formation varies depending on the composition of the exhaust gas components. This study examined the effect of different engine types, fuel atomization conditions, turbulence and emission control systems on emission species and specific reactivity. This was done using gas chromatographs and a high-performance liquid chromatograph to analyze exhaust emission species that affect ozone formation.