Emissions-Related OBD Systems: A Design Overview

On-board diagnostics, required by governmental regulations, provide a means for reducing harmful pollutants into the environment. Since being mandated in 1996, the regulations have continued to evolve and require engineers to design systems that meet strict guidelines. This one day seminar is designed to provide an overview of the fundamental design objectives and the features needed to achieve those objectives for generic on-board diagnostics. The basic structure of an on-board diagnostic will be described along with the system definitions needed for successful implementation.

Please note that because of proprietary considerations, this class does not provide details of algorithm design, algorithm performance, or algorithm application. The class will cover general OBD algorithm designs and the features required to promote sound OBD system design.

Individuals desiring a more in-depth look at On-Board Diagnostics should consider attending SAE seminar ID# C0707 Designing On-Board Diagnostics for Light and Medium Duty Emissions Control Systems.

What Will You Learn

By attending this seminar, you will be able to:
  • Articulate the underlying design objectives of on-board diagnostic systems
  • Apply the design features that all diagnostics need for successful implementation
  • Apply basic design techniques to deal with variation
  • Use a diagnostic design template in the development of an on-board diagnostic

Is This Course For You

This course is designed for engineers involved in either the design or control of on-board diagnostic systems for engines or transmissions. Individuals working in the heavy duty industry will find the information relevant, but should note that the examples will be based on spark ignition engines and light and medium duty regulations. In addition, engineers involved in engine and transmission hardware will benefit by obtaining a better understanding of the design of OBD systems. Engineers new to the area of OBD system design and engineers involved in the design of control systems wishing to obtain a better understanding of OBD requirements will also find the course valuable.

Materials Provided

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Course Requirements

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  • Fundamental Design Objectives for OBD Systems
  • Basic Design Features for OBD Systems
  • Defining "Good" vs. "Bad" Systems
  • Exercise: Defining Good vs. Defective Systems
  • Anatomy of an On-Board Diagnostic
  • Diagnostic Modeling
  • Understanding and Dealing with Variation
    • Decision making processes
    • Design guidelines for Exponentially Weighted Moving Averages (EWMA)