Pressure non-uniformity and mixing characteristics in stratified-charge rotary engine combustion

Stratified-charge combustion in rotary engines was studied using a three-dimensional model to compute intake, compression, liquid fuel injection, combustion, expansion, and exhaust. The model was applied to two engines of different displacement and at seven operating conditions. Good agreement is found between the measured pressure and the results of previous studies. The main feature of the combustion flowfield in the two engines, the slow and nonuniform mixing of fuel and air which leads to long and incomplete combustion, is attributed at least in part to low turbulent diffusivity within the rotor pocket. The TDC diffusivity in this type of rotary engine is shown to be lower than in corresponding reciprocating engines primarily because of the longer time between intake and TDC. The model also explains pressure nonuniformities that have been experimentally observed within the combustion chamber around TDC. The nonuniformity is due to the large fluid acceleration caused by the motion of the rotor. 34 references.

[1]  F. V. Bracco,et al.  On the Scaling of Impulsively Started Incompressible Turbulent Round Jets , 1982 .

[2]  John B. Heywood,et al.  Computer Models For Evaluating Premixed and Disc Wankel Engine Performance , 1986 .

[3]  Takumi Muroki.  Recent Technology Development of High-Powered Rotary Engine at Mazda , 1984 .

[4]  Frediano V. Bracco,et al.  Theoretical Analysis of Stratified, Two-Phase Wankel Engine Combustion , 1973 .

[5]  F. Bracco.  Modeling of engine sprays , 1985 .

[6]  C. R. Ferguson,et al.  Predicting the Emissions and Performance Characteristics of a Wankel Engine , 1974 .

[7]  Charles Jones,et al.  An Update of Applicable Automotive Engine Rotary Stratified Charge Developments , 1982 .

[8]  Charles Jones,et al.  A Progress Report on Curtiss-Wright's Rotary Stratified Charge Engine Development , 1974 .

[9]  Yolanda R. Hicks,et al.  Visualization of flows in a motored rotary combustion engine using holographic interferometry , 1986 .

[10]  J. M. Novak,et al.  The Prediction of Ignition Delay and Combustion Intervals for a Homogeneous Charge, Spark Ignition Engine , 1978 .

[11]  W. Sirignano,et al.  Theoretical Analysis of Wankel Engine Combustion , 1973 .

[12]  Robert W. Loyd.  Curtiss-Wright stratified charge rotary engine development , 1976 .

[13]  A. Humke,et al.  Heat Release Characteristics of Stratified - Charge Rotary Engines , 1987 .

[14]  Juan I. Ramos,et al.  Fuel-Air Mixing and Combustion in a Two-Dimensional Wankel Engine , 1987 .

[15]  Frediano V. Bracco,et al.  Studies Toward Optimal Charge Stratification in a Rotary Engine , 1976 .

[16]  Charles Jones,et al.  An Update of the Direct Injected Stratified Charge Rotary Combustion Engine Developments at Curtiss-Wright , 1977 .

[17]  T. I-P. Shih,et al.  A Two-Dimensional Numerical Study of the Flow Inside the Combustion Chamber of a Motored Rotary Engine , 1986 .

[18]  Charles Jones,et al.  The Curtiss-Wright Rotating Combustion Engines Today , 1964 .