ABSTRACT
As the requirements for lower and lower emissions continue, together with the need for better performance, other areas of engine control are constantly being investigated. This control is becoming even more important as the possibility of carbon dioxide emissions being included in future regulations increases. Some of the current and potential areas for further control of engine operation are included in this section. Although some of the common areas of ‘control’ have been covered in the previous two chapters, this chapter will cover some aspects in more detail and introduce further areas of engine control. Some of the main issues are: • Ignition timing. • Dwell angle. • Fuel quantity. • Exhaust gas recirculation (EGR). • Canister purge. • Idle speed. An engine management system can be represented by the standard threestage model as shown in Figure 10.1. This representation shows closed loop feedback, which is a common feature, particularly related to: • lambda control, • knock, • idle speed. The block diagram shown as Figure 10.2 can further represent an engine management system. This series of ‘inputs’ and ‘outputs’ is a good way of representing a complex system. This section continues with a look at some of the less common ‘inputs and outputs’.
