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Vehicle On-Board Diagnostic (OBD) regulations have long since expanded their original purpose of helping vehicle owners and technicians with malfunction diagnosis. In the United States and European Union, what was initially conceived as an effort to standardize electronic engine control (EEC) related diagnostics, has grown to a much broader scope, including in-use monitor performance ratio (IUMPR), telematics, real-driving emissions (RDE) monitoring, analysis and benchmarking of tailpipe emissions and fuel economy, Inspection and Maintenance (I/M) programs. OBD Telematics has even become a popular do-it-yourself (DIY) project topic; Brazilian OBD, on the other hand, remains mostly focused on the on-board monitoring of emissions related malfunctions. However, the improvement of Brazilian OBD regulations (OBD-Br) can be gradual; it does not need to incorporate the latest and most stringent California Air Resources Board (CARB) and European requirements at once and in full - e.g.

Misfire monitoring is currently a mandatory On Board Diagnostic (OBD) regulatory requirement in most of the main automotive markets. The most common method used for misfire detection is the one based on the calculation of the derivative of the angular crankshaft velocity in which sharp variations of the derivative signal are associated to misfire events. Therefore, the misfire detection calibration is practically unique for a given engine hardware and installation. Within this context, this Paper will present a practical evaluation and also a computational simulation of the impact of an engine hardware change (front end accessory drive dumpers) on the calculated angular acceleration signal and, therefore, on the overall misfire detection capability. The outcomes of this study will ultimately define the need of calibration changes as well as support a future development of an analytical method to predicted impacts in misfire calibration.

According to CONAMA Resolution 354/2004, all passenger and light commercial vehicles manufactured in or imported to Brazil (except compression ignition engines) must be equipped, from 2010 on, with the Brazilian On Board Diagnostic level 2 (OBDBr-2). Among the OBDBr-2 features, the misfire detection is by far the most challenging due to the Brazilian Flex Fuel context and also due to its interface with several powertrain components. Ford Motor Company has developed a series of peculiar studies and validation procedures to check the robustness and effectiveness of the OBDBr-2 misfire monitor. One of them focused on the correlation between engine production variation and misfire monitor detection capability. Experiments were performed varying the following characteristics: crankshaft position sensor air gap, torque to turn, spark plug depth and compression variation among cylinders.

This paper presents a comprehensive overview of Brazilian On-Board Diagnostic (OBD) regulations, Inspection and Maintenance (I/M) Programs and Aftermarket Catalyst regulations as well as an overview of similar regulations in the United States and Europe. Opportunities and technical risks are described in this context. Regulatory information contained in this Paper is intended to serve as reference only. Updated and complete rules and regulations must be used for official purposes. The implementation of the second stage of Brazilian OBD (OBDBr-2), starting in 2010, represents a significant improvement towards exhaust emission control and on-board diagnostic monitoring. Its effectiveness and credibility will be heavily influenced by how this new technology is integrated into I/M programs and how well it meshes with aftermarket catalyst regulations. Currently, Brazilian I/M regulations do not incorporate any OBD requirements and only Rio de Janeiro State has implemented an I/M Program.