An Analysis of Controlled Factors Improving Transient A/F Control Characteristics 890761
A control strategy for reducing transient Air/Fuel ratio excursions for improvements of transient engine responses is proposed through investigations of the various factors which affect transient A/F control results.
First, a large number of controlled parameters in transient A/F control such as fuel transport delay, injection timing, the static flow rate of injectors, sensing delay of the air flow rate etc. are discussed through analyzing the behaviors of both the indicated mean effective pressure Pi and A/F in various transient situations. In particular, the influence of injected fuel atomization is investigated with a visualization technique using an actually operating engine equipped with a visual manifold.
Then, a transient engine dynamics is formulated, taking into account the above controlled factors. Applicability of the dynamics to transient A/F control strategies is discussed.
Finally, we propose control strategies for reducing A/F transient excursions to get higher A/F control accuracy.