Flexible Design of Fuel Injecton and Ignition Systems for Gasoline Direct Injection Engines

Authors

BEng. H. Tokuda, Dr.-Eng. T. Yoshinaga, BEng. T. Nakashima, MEng. S. Sugiura, DENSO Corp., Aichi-ken; BEng. K. Saitoh, MEng. S. Okabe, NIPPON SOKEN, Inc., Aichi-ken

Year

2006

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 622

Summary

First generation “wall-guided” DISI engines had stratified lean combustion with a wide spacing between the injector and spark plug. In these engines, however, the combustion timing tended to be too early, leading to the inability to achieve ideal efficiency from the thermodynamic process. One proposal to overcome the disadvantages of “wall-guided” DISI engines is second-generation “spray-guided” DISI engines. It has stratified lean combustion with a close spacing between the injector and spark plug. In “spray-guided” DISI engines, the air-fuel mixture formation is independent of gas flow and piston movement. This enables the most significant possibilities for decreasing fuel consumption. Nevertheless, stratified lean combustion has been criticized for the costs and complexity of the aftertreatment required to achieve particulate and NOx emissions compliance. As one response to this problem, there has been a shift toward DISI development specific to stoichiometric homogeneous combustion. In this report, we will describe DENSO’s current status and the future of two critical technologies for DISI fuel spray and ignition. Specifically, we will describe a nozzle concept and a high-performance ignition concept. The first concerns a “multi-hole nozzle with highly flexible spray formation,” and the second concerns a “multi-spark ignition system with a high degree of energy flexibility.” In addition, we will describe advanced ignition methods involving a plasma and a laser ignition.

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