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DIGITAL ENGINE CONTROL SYSTEM 7
Figure 7.9a
Distributorless Ignition System
Although the mixture for modern emission-regulated engines is
constrained to stoichiometry, the spark timing can be varied in order to achieve
optimum performance within the mixture constraint. For example, the ignition
timing can be chosen to produce the best possible engine torque for any given
operating condition. This optimum ignition timing is known for any given
engine configuration from studies of engine performance as measured on an
engine dynamometer. More will be said about this topic when we discuss
closed-loop ignition timing later in this chapter.
UNDERSTANDING AUTOMOTIVE ELECTRONICS 241
