Idle speed control of a direct injection spark ignition stratified charge engine

Idle speed control is investigated for a direct injection, spark ignition, stratified charge (DISC) engine equipped with an electronic throttle. Such engines can be operated in multiple combustion modes. When operating in stratified charge combustion mode, they are very different from conventional stoichiometric engines, creating new opportunities for improved speed control. With current after-treatment technology, simultaneous high fuel economy and emissions conversion efficiency cannot be achieved by operating the engine in a steady-state manner: it must be cycled between running ultra-lean (for fuel economy) and rich (to service the after-treatment system). An idle speed control system is designed to meet the considerable feedback control demands required by these new engines. Copyright (C) 2001 John Wiley & Sons, Ltd.