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The fossil fuels burning is the main source of air pollutants in large cities. Anthropogenic emissions and their impact on air quality are of concern both regarding primary and secondary pollutants, such as tropospheric ozone. This molecule if formed from chemical reactions between fuel burning products, such as nitrogen monoxide and dioxide (NOx = NO + NO2) and volatile organic compounds (VOCs), in the presence of sunlight. With the perspective of increasing the biodiesel content in the mixture with diesel oil, actually in 12 % in Brazil, it became relevant to know the exhaust composition and it reactivity. This work presents a review of the literature and reveals that most scientific articles point out that biodiesel is a suitable alternative for such circumstances, however they point out harmful effects such as an increase in NOx emissions and carbonyls.

This paper reports and compares the performance of five motorcycles, four of them powered by Internal Combustion Engine (ICE) and one by an Electric Engine (EE). The power grade of those vehicles represents more than 80% of Brazilian motorcycle fleet. Motorcycles are submitted to standard routines, in accordance with regulations established by PROMOT (Control of Air Pollution for Motorcycles and Similar Vehicles). Main output parameters allowed for the assessment of their energy performance in respect to the energy source, followed by their greenhouse gases emission potential due to CO2, CH4 and N2O. The paper presents regulated emissions results for CO, THC and NOx, provided by EE and ICE engines. Different ICE motorcycles are tested, and fueled by a range of ethanol/gasoline contents from 22 to 100%, allowing to analyze the influence of the renewable biofuel on the motorcycle energetic efficiency and emissions.

Over the past decade, society’s concern for the state of the environment has increased. Several actions have been taken by governments, non-governmental organizations, public and private environmental and health agencies to limit pollutant emissions. Within this context, the control of vehicle emissions has become increasingly stringent. Emission limits have been substantially reduced, and the role of unregulated emissions is increasing in importance. Ammonia is the third most abundant nitrogen compound in the atmosphere. Ammonia emissions have received special attention due to their contribution to secondary particulate matter production in the forms of ammonium nitrate (NH4NO3) and ammonium sulfate ((NH4)2SO4). The aim of this work was to evaluate the effect of fuel sulfur content on ammonia emissions in a Euro III motorcycle.

Gasoline direct injection (GDI) vehicles are considered to be one of the solutions for engine optimization with regard to fuel consumption. This combustion system potentially provides, depending on the duty cycle, an improvement in fuel economy of 5 - 10%. In Brazil, mainly due to new requirements to reduce consumption imposed by the Inovar Auto automotive regime, this technology is becoming more popular and in 2013 the first flexfuel GDI vehicle was produced. However, GDI engines tend to produce more particulate matter compared to conventional engines. The present article is based on the study of particulate matter emissions from a GDI vehicle tested according to the FTP75 (Federal Test Procedure 75) and HWFET (Highway Fuel Economy Test) cycles. The vehicle was fuelled with gasoline (A22) and with hydrated ethanol (HER). It was observed that the particulate matter formed after the combustion process is directly related to the fuel properties.

Motorcycle sales have increased consistently during the last decade mostly in developing countries, especially in the BRICS. Low cost and less fuel consumption comparing to cars associated to the economic growth are the main reason for such trend. Emission limits have become stricter and the use of gas after treatment devices is widely present in new models. Flex fuel motorcycles have now become available, but effects of the combination of diverse gasoline/ethanol blends on the emissions are still an open issue that requires further understanding. This paper presents the most recent results regarding regulated and unregulated emissions from a Flex Fuel motorcycle fuelled with 4 different gasoline/ethanol blends: E22, E61, E85 and 100% ethanol. Both regulated (CO, THC, NOx) and unregulated emissions (Aldehydes, NMHC, NH3, N2O) were studied.

Vehicular emissions limits have been reduced throughout the world in compliance with environmental legislations. With the rapid increase in the number of flex-fuel vehicles on the market, the consumption of ethanol has also increased. As a result, there is expected to be a large abundance of unburned alcohol from tailpipe gas emissions. Another important factor arising from the use of ethanol is the formation of tropospheric ozone. The objective of this study was to measure the amount of unburned alcohol and legislated emissions as well as the ozone formation potential of a passenger (light-duty) vehicle fueled with gasoline containing different concentrations of ethanol. The main conclusion is that unburned alcohol emissions increase in direct proportion to the ethanol content in the fuel. The unburned alcohol was measured by two techniques: gas chromatography and FTIR.

Some chemical characteristics and natural impurities of diesel fuel used in diesel engines may damage the operation of emission control devices as well as contribute to the formation of secondary pollutants in the atmosphere. Sulfur is one of the natural impurities of diesel fuel, which upon burning, combines with oxygen to form SO2, creating emissions that adversely affect both the environment and human health. Many countries around the world have adopted stringent diesel emission standards to drastically reduce the sulfur content in diesel fuel and thereby improve air quality. Many authors have addressed the need to regulate transportation fuel emissions from pollutants, including sulfur (S), carbon monoxide (CO), particulate matter (PM), nitrogen oxides (NOx) and hydrocarbons (HC). This paper addresses both regulated and non-regulated emissions from four types of diesel fuels, each with a different sulfur concentration.

In order to comply with the introduction of new emission limits, motorcycles have been equipped with electronic injection systems and three-way catalytic converters for emissions abatement. However, these converters produce unwanted reactions, such as the formation of ammonia. This paper was focused on ammonia emission reduction in motorcycles. To provide ammonia abatement, one SCR (Selective Catalytic Reduction) catalyst has been developed and installed in a fourstroke motorcycle in addition to the original one, a three way catalyst (TWC). SCR systems work by chemically reducing NOx (NO and NO2) to nitrogen (N2). This is an experimental research work conducted by the Research and Development Institute (Lactec) and the Umicore Automotive Catalysts. Regulated and unregulated emissions have been measured in a chassis dynamometer test cell.