Automotive Computer Controlled Systems

Improvements in design, materials and manufacturing techniques have combined to produce vehicles that are, in general, very reliable. Many servicing and repair tasks, such as rebores, big-end repairs, gearbox overhauls etc., are no longer commonplace and this sometimes gives the impression that today’s vehicle technicians do not need the range of skills that once were necessary.
It may be the case that the so called ‘traditional’ skills are less important, but the change in automotive technology that has resulted from the introduction of many computer controlled systems has meant that technicians require additional skills.

These additional skills are discussed. However, it remains the case that technicians need to have a thorough understanding of technical and scientific principles that lie behind the operation of vehicle systems. For example, an exhaust emission system may be malfunctioning and a first reaction might be that the exhaust catalyst has failed. But what about other factors, such as air filter, fuel pressure, condition of the injectors, condition of the ignition system, engine valves, cylinder compression etc.? I have assumed that most readers of this book will be engaged in vehicle service work, in training or education and that they will have knowledge of the basic technology and science that enables them to ‘think through’ the connections between defects in computer controlled systems and the factors that may be contributing to them.

The text concentrates on areas of technology that are common to a range of systems. For example, air flow meters are a common feature on most petrol engines and they are of two types: volumetric flow (the flap), and mass flow such as the hot wire and the hot film. The outputs from these sensors are broadly similar and they can be measured accurately with the type of equipment that is described.

Most exhaust gas oxygen sensors are of the zirconia type and the output signals, on almost all vehicles to which they are fitted, will be broadly identical.
There are families or groups of sensors and actuators that operate on broadly similar principles and this makes them amenable to testing by means that are widely available. When an object, such as a sensor, bears similar properties to other objects it may be referred to as belonging to a genus and the term ‘generic testing’ is sometimes used since the tests can be applied to most, if not all, of the same type of sensor. Many diagnostic equipment manufacturers are now making equipment that enables technicians to perform a wide range of tests on computer controlled systems. The aim of this book is to show how, with the aid of equipment, suitable training and personal endeavour, service technicians and trainees may equip themselves with the knowledge and skill that will permit them to perform accurate diagnosis and repair.

Chapters 5, 6 and 7 show how knowledge of the technology that is common to many of the systems can be used to perform effective diagnosis on a range of computer controlled systems. Also covered is a range of modern computer controlled systems, computer technology and features such as CAN and OBD II.

This book has been designed to meet the needs of students and trainees who are working for NVQ level 3, BTEC National Certificate and Diploma, Higher National and similar vocational qualifications. However, the treatment of topics is sufficiently broad as to provide useful background knowledge for students of design and technology, and those on computing courses who are studying in schools and colleges. DIY motorists, particularly those with an interest in computing, may also find the book helpful in obtaining a better understanding about their own vehicles, particularly in relation to features such as the European OBD, which is likely to cause widespread attention when it becomes more widely used in the UK.

CONTENTS

• 1 Common technology
• 2 The Computer ECM
• 3 Self-diagnosis and fault codes
• 4 Diagnostic tools and equipment
• 5 Sensors
• 6 Actuators
• 7 Diagnostic techniques
• 8 Additional technology

Language: English
Format: PDF
Pages: 266

Automotive Computer Controlled Systems