1995-02-01

Variable Orifice Geometry Verified on the Two-Phase Nozzle (VRD) 950081

Innovative solutions for reducing particulate emissions will be necessary in order to comply with the even more stringent exhaust-gas standards of the future.The potential of a diesel nozzle with variable orifice geometry has long been common knowledge in the area of engine construction. But up to now, a fully functional solution of such a nozzle has not appeared which operates with a reduced orifice at low engine speeds and/or low loads. Here with regard to target costing, the requirements implicit in function and manufacture must also be taken into account.Using calculations on nozzle interior flow and injection-spray investigations, it will be shown which nozzle geometries best fulfill the various requirements. In order to achieve low levels of particulate emission in an engine with a combustion chamber designed for optimum use of a hole-type nozzle, the injection-spray direction and its geometry must to a large extent correspond to those of a hole-type nozzle. This is decisive for the two-phase nozzle (VRD) to make full use of its potential in a conventional combustion chamber.The two-phase nozzle with spray orifices arranged directly above one another provides the solution to this problem.The spray geometry for the variable-orifice nozzle has been realised. The application of the needle control for the FTP75 test procedure is being worked on.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: Purchase more aerospace standards and aerospace material specifications and save! AeroPaks off a customized subscription plan that lets you pay for just the documents that you need, when you need them.
X