Thomas Kuhn

The Application of Variable Event Valve Timing to a Modern Diesel Engine

DaimlerChrysler and Mechadyne have undertaken a piece of work to investigate the opportunities for improving the operation of light duty diesel engines using variable valve timing. The very high compression ratios used in this type of engine make it essential to be able to alter the valve open periods to affect exhaust valve opening and intake valve closing, whilst leaving the valve motions largely unchanged around overlap top dead centre to avoid valve to piston contact. This paper presents an overview of the design solution, a description of the simulation model used, performance and economy data predicted by the model and a discussion of other areas of opportunity where improvements may be possible.

DP-based wordgraph pruning

We present an efficient technique of generating word graphs in a continuous speech recognition system. The word graph is constructed in two stages. In the first stage, a huge word graph is generated as a by-product of a beam-driven forward search. Based on a dynamic-programming (DP) method, this huge word graph will be pruned in the second stage using higher level knowledge, such as n-gram language models. In this pruning stage an edge is removed if there is no path going through this edge which is better scored as the best-scored path in the word graph. The proposed technique is evaluated in the German VERBMOBIL task.