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On-board measurement is a powerful method to assess vehicular exhaust gas emission, since it enables the acquisition of instantaneous raw emission values in real-world conditions. While the vehicle emissions are subject to traffic and environment fluctuations, on-board measurement is a fast and economical way to generate data for fleet emission inventories, for instance. It is part of the mandatory testing for heavy-duty vehicles in the USA, as regulated by the USEPA. In 2004, Petrobras (Brazilian Oil Company) first experienced on-board emission measurements while participating in an international joint project, whose objective was to obtain information regarding the light-duty vehicular gas emission contribution to pollutant levels in some of the major Latin-American cities.

In last few years, Petrobras has been working to make feasible the vehicular usage of the natural gas (NG) produced in Brazilian north region. This gas is produced in the Urucu field located at the Amazon forest. Due to its low methane and high nitrogen contents that could promote, respectively, performance losses and higher NOx emissions, Urucu's gas does not meet ANP specification for vehicular natural gas. Previous studies performed at Petrobras Research Center (CENPES) indicated the possibility of vehicular application for Urucu's NG, attending the Brazilian emission legislation (PROCONVE). However, with new PROCONVE's phases, recent vehicles have more advanced technological levels of fuel injection and catalyst systems, which require that kits for natural gas follow this evolution, including interfacing with flexible fuel engines.

In the last years, world's general concern about climate changes and their effects on human life has strongly increased. Some countries, such as European Union members and the USA, are improving their legislations in order to limit vehicular CO2 emissions. To comply with these limits, new vehicle and fuel technologies are being developed in many places. Thus, the main goal of this paper is to present a comprehensive overview of some of these technologies for light-duty vehicles based on international published references and some experiences of Petrobras Research Center (CENPES). Also, this work addresses to some regulatory initiatives, such as new CO2 emission legislations and fuel economy labeling programs.

The growing humanity concern about harmful effects of global warming in consequence of greenhouse gases (GHG) emission has been translated on CO₂ emission reduction targets for the next years in many countries. These targets and regulations for exhaust gas pollutants with local effects have led to the introduction of new vehicular technologies as gasoline direct injection or hybrid vehicles, for instance. New fuel developments, including alternative ones, have already been an important contribution. In the United States, up to 2016, all manufacturers shall accomplish with the average production target of 34.1 mpg, becoming 49.6 mpg in 2025. In Europe, the 2015 target is 130 g/km of CO₂ average emission by each manufacturer production and reduced for 95 g/km in 2020. Japan, China, India and other countries have their own limits defined for the next years too.

This paper presents a methodology proposed by the PETROBRAS Research Centre (CENPES) to simulate in a laboratory a route performed during field emission tests run with an on-board emission measurement system. It also includes the procedure followed to build the drive cycle and to implement it at the CENPES' Vehicle Test Laboratory. Laboratory simulation of local urban routes, for instance, allows analyzing the impact of a new fuel formulation on the emission levels of a local fleet with higher accuracy and repeatability, as the test conditions can be better controlled. The usage of on-board emission measurement systems is more expensive and is subject to fluctuations in the traffic conditions, making comparative tests more difficult. In order to generate the new cycle, data acquired during the field tests was used to determine speed profiles and an average speed distribution was calculated.

This paper presents a proposed methodology developed during a research project at CENPES - PETROBRAS Research Center, to simulate a typical urban traffic cycle in the city of São Paulo on a chassis dynamometer. This cycle can be used in pollutant gas emission tests for light duty vehicles in laboratories. The implementation of a representative city cycle in a laboratory allows its simulation under controlled conditions. It can be applied, for example, in emission inventories and the impact of air quality in public health studies, without the need for on-board emissions measurement equipment for field use. This kind of equipment is generally expensive and the repeatability for the same cycle can be difficult to achieve, mainly due to traffic variants such as the day of the week, time, and weather conditions.

Fun to drive is one of the main driver’s wishes. Therefore, it is a relevant attribute in vehicles and fuels development. Vehicles performance depends, mainly, on ignition and fuel injection strategies adopted by their manufacturers. However, fuel characteristics may significantly influence acceleration and speed recovery results. Regarding fuel development, it is important to establish test methodologies, which minimize experimental uncertainties. So, it is possible to detect any small acceleration or speed recovery variation and relate it to fuel characteristics changes. An alternative to traditional track tests is to perform speed recovery tests on chassis dynamometer, where it is possible to mitigate the effect of some parameters which may significantly vary on track, such as, ambient temperature, ground irregularities and wind direction and speed.