Diagnostic System for Electronic Fuel Injection Engines Pedro Maria de Sousa Melo Correia Duarte (IST n. 50823) Dissertation submitted for obtaining the degree of Master in Electrical and Computer Engineering Proposal 251/2007 Thesis Committee President: Prof. José António Beltran Gerald Advisor: Prof. Moisés Simões Piedade Members: Prof. Leonel Augusto Pires Seabra de Sousa Prof. Francisco André Corrêa Alegria September 2007 To all of those who always fed my interest in engineering, specially my grand fathers, my uncles and my father. I would probably be a rich doctor by now if weren't for you. i Acknowledgements Acknowledgements Before going into any further details of my thesis I believe that I must mention all the people and companies who made my work possible or at least eased the way as much as they could. Among these there are three special acknowledgements that have to be made to the ones whose contribution was invaluable. These are my parents and grandparents who gave me all the support they could, both financially and emotionally, throughout my academic process; my supervisor Dr. Moisés Piedade who accepted to guide my work and whose passion for electronics has been a key factor on my personal motivation on this course; and at last but not less important than the others, my colleague Paulo Louro who assisted me on every doubts I came across regarding both hardware and software development. I must also express my profound appreciation for the following individuals: Eng. Victor Silvestre from Fatrónica, Fabrico de Artigos Electrónicos, S.A. who provided me with testing hardware for the development of the on-board car computer, Dr. Francisco Alegria who reviewed my thesis for its final presentation, Mrs. Marli Gomes and Mr. Manuel Ribeiro for the assistance with laboratory material requests, and the team of soon-to-be engineers who shared the laboratory with me and helped me to keep the good mood through the entire project. As of communities I have to thank to all the members of the DIY community of pgmfi.org who researched the electronic control units used in Honda engines. Without their investigation which is underway for at least 10 years it would have not been possible to achieve the results I got. I also must express my sincere appreciation for the community vtec.pt which helped me in many ways regarding the vehicle that was the subject of my research. ii Abstract Abstract For the last 30 years, the automotive industry has been feeling the strong impact of electronic components in their end-products. Part of the technology that started being used for the simple control of headlights and brake lights soon became part of more complex embedded systems that reached many areas of the vehicle ranging from vital security applications to multimedia appliances. On extremely advanced vehicles the electronics and harness hardware used may reach up to 70% of the total cost of the final product. With the growth of the concurrent market for OEM and aftermarket off-the-shelves multi-purpose devices, standards regarding communication between the vehicle and these third party appliances had to be defined. Originally developed in 1980, CAN bus was created to establish a consensus in intra-vehicle communication. It sill is one of the most successful protocols for serial communication nowadays and is already employed outside the automotive industry. However, in an age where critical functionality such as X-by-Wire tends to earn more market place, more reliable and faster buses are required. The work presented in this paper explores one possible approach to develop a console that integrates three standards of communication with low cost interfaces. After exhaustive research CAN bus, LIN bus and USB were chosen to integrate this prototype in order to allow transmission speeds up to 1Mbps concerning the third party peripherals and up to 12 Mbps towards the vehicle on-board computer. Although examples for all the buses were provided, the main functional objective of this thesis is to give the driver the possibility to interact with the engine ECU, using this platform, in a vehicle that was not prepared for the effect at the time of its design. The achieved result was the ability to gather real time information about the conditions of an internal combustion engine and to be able to interact with mechatronic peripherals on the fly. Keywords Automotive Communication, CAN bus, LIN, On-board Computer, ECU, Datalogging iii Resumo Resumo Desde há 30 anos que a indústria automóvel tem vindo a sentir o grande impacto dos componentes electrónicos nos seus produtos finais. Parte da tecnologia que começou por ser usada para o simples controlo de faróis e luzes de travagem rapidamente se tornou parte de sistemas embebidos mais complexos que afectam várias áreas do veículo, desde aplicações de segurança crítica até aplicações multimédia. Em veículos extremamente avançados, todos os componentes electrónicos e cablagem utilizados podem chegar a 70% do valor total do produto final. Com o crescimento do mercado paralelo de peças originais ou componentes genéricos para diversos fins, protocolos de comunicação entre o veículo e estes dispositivos tiveram de ser definidos. Originalmente desenvolvido em 1980, o CAN bus for criado para estabelecer o consenso em comunicação interna automóvel. É hoje ainda um dos mais populares protocolos para comunicação em série e já é utilizado fora da indústria automóvel. Contudo, numa era onde a funcionalidade critica como o X-by-Wire tende a ganhar mais lugar no mercado, protocolos mais fiáveis e rápidos são necessários. O trabalho apresentado neste documento explora uma abordagem possível ao desenvolvimento de uma consola que integra três protocolos de comunicação de baixo custo. Após uma pesquisa exaustiva CAN bus, LIN bus e USB foram escolhidos para integrar este protótipo de forma a permitir velocidades de transmissão até 1 Mbps considerando os periféricos automóveis e até 12 Mbps considerando o computador de bordo. Apesar de terem sido criados exemplos para todos os barramentos de dados implementados, a principal objectivo funcional desta tese é dar a possibilidade de interagir com a ECU do motor, utilizando esta plataforma, num veículo que não está preparado para o efeito de fábrica. O resultado obtido foi a capacidade de observar em tempo real informação sobre as condições de um motor de combustão interna e conseguir interagir com periféricos mecânicos e eléctricos de forma instantânea. Palavras-chave Comunicaçao automóvel, CAN bus, LIN, Computador de Bordo, ECU, Registo de Dados iv Table of Contents Table of Contents Acknowledgements................................................................................. ii Abstract.................................................................................................. iii Resumo ................................................................................................. iv Table of Contents.................................................................................... v List of Figures .......................................................................................viii List of Tables........................................................................................... x List of Abbreviations............................................................................... xi 1 Introduction ..................................................................................1 1.1 Overview.................................................................................................. 2 1.2 Motivation and Contents.......................................................................... 3 2 Protocols ......................................................................................5 2.1 Introduction.............................................................................................. 6 2.2 Protocol Overview ................................................................................... 6 2.2.1 IEBus overview – Class A ..................................................................................... 6 2.2.2 Motorola Interconnect (MI) Overview – Class A.................................................... 7 2.2.3 SAE J1708 overview – Class A............................................................................. 7 2.2.4 Local Interconnect Network (LIN) overview – Class A .......................................... 7 2.2.5 J1850 overview – Class A ..................................................................................... 8 2.2.6 Distributed Systems Interface (DSI) overview – Class B ...................................... 8 2.2.7 Intellibus overview – Class B and C ..................................................................... 8 2.2.8 Controller Area Network (CAN) overview – Class B and C................................... 9 2.2.9 FlexRay overview – Class C.................................................................................. 9 2.2.10 Media Oriented Systems Transport (MOST) overview – Class C....................... 10 v 2.2.11 On-Board Diagnostic (OBD) overview – Class C ................................................ 10 2.2.12 Byteflight (SI-Bus) overview – Class C................................................................ 11 2.2.13 Bosch-Siemens-Temic (BST) overview – Class C .............................................. 11 2.2.14 Mobile Multimedia Link (MML) Overview – Class C............................................ 12 2.2.15 Domestic Digital Bus (D2B) overview – Class C ................................................