Automotive systems offer a rich opportunity for hybrid models, controls, and tools. Beyond the traditional use of hybrid models for representing the behavior of the composition of discrete controller and continuous plants, automotive mechanical systems exhibit hybrid behavior as demonstrated in this chapter. In addition, hybrid systems can be used to capture system specifications at the highest level of abstraction and to model implementation architectures thus enabling a rich design space exploration.

Introduction

This chapter presents an application of hybrid systems that is of significant industrial interest: power-train modeling and control for automobiles.

Engine control is a challenging problem that involves many functional and non functional requirements. The problem is to develop control algorithms and their implementation with guaranteed properties that can substantially reduce emissions and gas consumption with increased performance.

The introduction of hybrid system modeling and control was motivated by the need for verifying closed-loop systems where the plant to be controlled are continuous-time systems and the controller is a digital system. However, hybrid models are general enough to be useful in other areas of design. In particular, engine control offers a rich set of application of hybrid systems:

• The power-train itself can be represented as a hybrid system. In fact, an accurate model of a four-stroke gasoline engine has a “natural” hybrid representation:

• Each cylinder in the engine has four discrete modes of operation corresponding to the stroke it is in (hence, its behavior is well represented by a finite state machine (FSM)). […]