The Demands of Cylinder Event Control

In the context of engine control the strategy is a statement of the control functions. Modern strategies are generally map based with a resolution corresponding to single cylinder events. However, future needs point to high speed control based on sensors which can observe cylinder events. Such sensors working with actuators such as gasoline and diesel fuel injection can act to minimise variations between cylinders and more closely control combustion conditions.

A high speed strategy is a functional description of control which includes such high speed functions One strategy can be solved using different control structures and with different sensor types. A cascaded control scheme for example would allow high speed cylinder level controls to be fed by slower controllers able to take a longer term view. Such a cascaded scheme is a framework which allows high level diagnosis and control objectives to be realised within a common framework.

High speed controls will allow loop closure: an important feature which relaxes some of the accuracy requirements on system models.

High speed controls make demands on software development tools, but the greatest impact is likely to be in the architecture of the control system. High performance sensors may well offload some traditional centralised tasks. The adoption of high speed control is a cost driven one and requires the sensing technology to be highly integrated. Some peripheral sensors (mainly temperature and pressure) may also be eliminated once cylinder conditions can be sensed reliably.