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Computational Fluid Dynamics (CFD) is frequently used to predict complex flow phenomena and assist in engine design and optimization. The scavenge process within a 2-stroke engine is key to engine performance especially in high performance racing applications. In this paper, FLUENT CFD code is used to simulate the scavenging process within a 125cc single cylinder racing engine. A variety of different port designs are simulated and scavenge characteristics compared and contrasted. The predicted CFD results are compared with measured scavenge data obtained from the QUB single-cycle scavenge rig. These results show good agreement and provide valuable insight into the effect of port design features on the scavenging process.

The incorporation of one-dimensional simulation codes within engine modelling applications has proved to be a useful tool in evaluating unsteady gas flow through elements in the exhaust system. This paper reports on an experimental and theoretical investigation into the behaviour of unsteady gas flow through catalyst substrate elements. A one-dimensional (1-D) catalyst model has been incorporated into a 1-D simulation code to predict this behaviour. Experimental data was acquired using a ‘single pulse’ test rig. Substrate samples were tested under ambient conditions in order to investigate a range of regimes experienced by the catalyst during operation. This allowed reflection and transmission characteristics to be quantified in relation to both geometric and physical properties of substrate elements.

Engine cycle simulation is an essential tool in the development of modern internal combustion engines. As engines evolve to meet tougher environmental and consumer demands, so must the analysis tools that the engineer employs. This paper reviews the application of such a tool, VIRTUAL 4-STROKE [1], in the modelling of a benchmark 1.9 Litre TDI engine. In an earlier paper presented to the Society [2] the authors presented results of a validation study on the same engine under full load operation. This paper expands on that work with validation of the simulation model against measured data over a full range of part load operation.

This paper describes a technique whereby race car airbox performance can be assessed directly in terms of predicted engine performance by coupling a one-dimensional engine model on a timestep-by-timestep basis to a three-dimensional computational fluid dynamics (CFD) model of an airbox. A high-performance three-litre V10 engine was modelled using Virtual 4-Stroke unsteady gas dynamics engine simulation software, while two airbox configurations, representative of those used in FIA Formula 1 (F1), were modelled using general purpose CFD software. Results are presented that compare predicted engine performance for the two airbox geometries considered in the coupled simulations. Individual cylinder performance values are also presented and these show significant variations across the ten cylinders for each airbox simulated.

One-dimensional (1-D) modelling codes are now commonplace in engine simulation programs. Thermodynamic analysis associated with the unsteady gas flow through engine ducting is an important element within the modelling process. This paper reports on a new approach in analysing mass and energy transport through a pipe system using the mesh method. A new system has been developed for monitoring wave energy and gas properties, using a two-dimensional grid to represent the time-mesh boundary domain. This approach has allowed for refinement of the current mesh method by allowing more accurate monitoring of gas properties. The modified method was tested using measured results from a Single-Shot Rig. A CFD analysis was also conducted and compared with the new method. The new method performed very well on the range of pipe geometries tested.