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Ebook Understanding automotive electronics (5th edition): Part 2

(BQ) Part 2 book "Understanding automotive electronics" has contents: Digital engine control system, vehicle motion control, automotive instrumentation, diagnostics, future automotive electronic systems. | 2735 | CH 7 Page 223 Tuesday, March 10, 1998 1:15 PM DIGITAL ENGINE CONTROL SYSTEM 7 Digital Engine Control System Chapter 5 discussed some of the fundamental issues involved in electronic engine control. This chapter explores some practical digital control systems. There is, of course, considerable variation in the configuration and control concept from one manufacturer to another. However, this chapter describes representative control systems that are not necessarily based on the system of any given manufacturer, thereby giving the reader an understanding of the configuration and operating principles of a generic representative system. As such, the systems in this discussion are a compilation of the features used by several manufacturers. In Chapter 5, engine control was discussed with respect to continuoustime representation. In fact, most modern engine control systems, such as discussed in this chapter, are digital. A typical engine control system incorporates a microprocessor and is essentially a special-purpose computer. Electronic engine control has evolved from a relatively rudimentary fuel control system employing discrete analog components to the highly precise fuel and ignition control through 32-bit microprocessor-based integrated digital electronic power train control. The motivation for development of the more sophisticated digital control systems has been the increasingly stringent exhaust emission and fuel economy regulations. It has proven to be cost effective to implement the power train controller as a multimode computer-based system to satisfy these requirements. A multimode controller operates in one of many possible modes, and, among other tasks, changes the various calibration parameters as operating conditions change in order to optimize performance. To implement multimode control in analog electronics it would be necessary to change hardware parameters (for example, via switching systems) to accommodate various operating conditions. In a .