Study On The Generic Combustion Characteristics For Turbocharged Direct Injection Gasoline Engines

Turbocharged direct injection gasoline engine is the main development directionof gasoline engine in the future. The engine combustion process has a greatrelationship with the heat-work conversion process efficiency, combustion efficiency,combustion stability and emissions levels of this engine, which directly affect engineperformance. Studying on the general trends of in-cylinder combustion characteristicsis of great significance, because these general trends can be applied to the originaldesign and simulation model optimization of turbocharged direct injection gasolineengine. Due to the direct injection turbocharged gasoline engine was come out late,only little research was done on the combustion process of this engine.Firstly, study the general trends of combustion characteristic parameters withdesign and operation parameters in this paper. And then， find out the relationshipbetween the performance parameters with design and operation parameters.In order to find out the general trends, the tests of three engines were completed,which could help to establish data base of engine performance, combustion andoperation data. Then, Build the main relations of the in-cylinder combustioncharacteristic parameters with the main operation parameters, such as the engine speed,load, λ (excess air ratio), boost pressure and ignition advance angle.After studying on the results of three engines, it is concluded that: combustionefficiency of fuel has almost linear downward trend with the decrease of λ; burningduration is mainly affected by the engine load;50%burning position is mainlyinfluenced by engine knock sensitivity which closely related to engine speed and boostpressure; combustion quality parameter keeps at around2in almost all conditions;heat-power conversion efficiency is mainly affected by the compression ratio,combustion duration,50%burning position and λ; NOXemission is mainly affected byλ and spark advance angle; CO emission and λ also have a linear relationship, and COemission increases with the decrease of the λ; HC emission has no obvious relationwith engine performance or combustion characteristic parameters.