Low No{sub}x-emission development for S4000 common rail diesel engine

摘要

The compact superturbocharged diesel engines developped by MTU have a wide application spectrum: marine propulsion, stationary genset, off-highway vehicles, and rail traction. The important design goals are low fuel consumption and compliance with low NO{sub}x emission requirements by law as well as a good stationary "performance map" and a fast dynamic load response. These have been the primary technical goals for the development of the new engine series 4000 introduced into the market in 1996-98. To realize the thermodynamic success factors an innovative injection system and a matching turbo charging system is of utmost importance. The common rail injection system (CR-system), realized for the 4000 engine the first time for an non-automotive engine, offers the potential to optimize the high pressure combustion process in the cylinder. This is due to the decoupling of the high pressure fuel generation and the injection with respect to location, time and function. The CR-system offers new degrees of freedom to optimize the combustion in the complete operating range of the engine. Programming all injection parameters in the electronic engine control system in-situ the engineer can perform all engine tests very quickly and efficiently. The methodology to define the thermodynamic working process for low NO{sub}x emission is discussed for the 12V marine engine. The simulation of the hydraulics of the CR-system, the 3 dimensional fuel spray and the air-fuel mixing phase as well as the simulation of the air and exhaust system give the basis to design the experiments of the 1-cylinder test engine. The results are transferred to the 12 cylinder series engine.