Search Results

The first part of the paper gives an overview of the current results obtained with the first-generation of GDI-powered vehicles launched on the European market. In view of the rather limited success in fuel consumption gain the second-generation of very lean stratified layouts has begun, but this process requires the development and application of new high-level analysis tools. A possible high performance approach is the multi-purpose use of 3-D numerical simulation both in the development and the engine control strategy calibration phases. The development of a small 1.6 liter lean stratified engine project was chosen to demonstrate the dual application capability of the NCF-3D simulation tool. The paper continues with a description of the engine application frame, the basic features of the NCF-3D simulation tool and the latest enhancements made to combustion and fuel composition models within the software frame.

The success obtained by use of Virtual Engine Modeling (VEM) in the design and development areas of fuel injectors generated a lot of interest from production and quality engineers to possess a similar tool related to spray vessel measurements. To respond to stringent PL6/EURO5 requirements it was decided to develop a Virtual Spray Vessel (VSV) tool capable of predicting spray patterns and perform droplet diameter analysis comparable to real-time Phase Doppler Analysis (PDA) results. The paper describes the analogies between VEM and VSV modeling and the specific new numerical approaches to obtain spatial spray data comparable to conventional mechanical measurement techniques and to perform droplet diameter analysis comparable to PDA data. The paper concludes with a series of comparisons of simulated and experimental data from virtual and real-time measurement vessels.

The paper presents the background physics of droplet coalescence phenomena and the basic research carried on the topic by interactive use of high-level 3-D numerical simulation tools and high-level optical visualization and measurement techniques. The presentation continues with the description of a new injector atomizer plate layout, which enables a physical coalescence control of the droplet population within the entire fuel spray. Finally are presented examples of the impact on exhaust emissions of the introduction the new atomizer plate with coalescence control by engine test bed experiments (steady state low load conditions) and vehicle tests (first cold part of the FTP-cycle).

The paper presents the main reasons for the increasing market share of vehicles with the capacity to run on random bio fuel blends. It describes the philosophy and basic layout of current integral flex mixture preparation systems. The paper demonstrates the necessity to introduce a series of new high-performance analysis tools for further improvement of the mixture preparation system and in particular the fuel injector performance. The paper continues with a discussion of the basic structure of the interactive Virtual Engine Model approach applied to fuel injector atomizer optimization. Test results obtained by application of the new tools to two different series production flex engines are presented. The impact of the improved spray formation capability of the optimized fuel injector atomizers is explained and experimental vehicle FTP-cycle data are reported and discussed.