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The required fuel spray characteristics, controlled fuel pressure, and injector installation configurations in gasoline direct injection differ among manufacturers. As a result, there are currently a variety of injector types and configurations being proposed by many different component manufacturers. This paper proposes a new injector design that both enables high fuel pressure operation by utilizing a highly efficient electromagnetic valve using a composite magnetic material for the injector actuator, and increases manufacturing productivity while also meeting the requirements of each engine manufacturer by simplifying the construction of the injector.

Fuel atomization is known as an effective means of reducing the exhaust emissions of internal combustion engines. We have focused on a multiple-hole nozzle as a cost-effective atomization method that does not require any auxiliary devices or an external energy source to carry out atomization. In this report, we will discuss the facts that 1) the primary factors of atomization with the multiple-hole nozzle lie in the flow upstream of the nozzle, and 2) the atomization characteristics such as spray droplet diameter and spray spatial distribution when the factors which effect atomization with the multiple-hole nozzle are changed. As a result, with our newly developed 12-hole nozzle injector in an actual engine, we found an HC reduction effect greater than that of a conventional air-assist injector.

Fuel atomization is known as an effective means of reducing exhaust emissions from internal combustion engines. In this study, we present a cost-effective atomization method for multiple-hole nozzle gasoline injection systems that requires no auxiliary device or external energy source to carry out atomization. While many studies have been conducted before on the atomization mechanism, most assume that the key to atomization lies in the nozzle configuration or the interaction between the fuel spray and ambient air. We, on the other hand, paid particular attention to the fuel nozzle upstream flow and found how it plays a crucial role in fuel atomization. In case of using multiple-hole nozzle in particular, atomization is greatly influenced by impingement of upstream flow of the fuel nozzle, which leads to rapid directional change in the fuel flow.

This paper presents a new method of numerical analysis of 2-dimensionnl incompressible flow which is useful for a stage of product design, developed on the basis of both FEM and FDM, and also a new model of vorticity shedding has been developed. A computer simulation program was employed to confirm the following features of the present method. 1) The flexibility of any object shape by FEM. 2) The stability of the calculation by the modified FLIC* method (FDM). 3) The approximation of the flow separation on the boundary by the vorticity generating model. After applying the program to the design of the two types of air flow meters; i.e., the vane and Karman types, it has been found that the program is practically useful to obtain the optimum design of air flow meters.