Abstract:

Since both the structure and the operating parameters of a diesel engine change nonlinearly, the heatload and heat radiation area are directly influenced by the ratio of piston stroke to cylinder diameter(S/D).In thispaper,an optimized mathematical model is established for moderate-speed and high-speed diesel engines,with the minimal heat radiation area as the object function and the S/D value as the variable.In the condition of non1inear constraints,the proposed model is optimized by Sequential Quadratic Programming(SQP)on Matlab system.An illustrated analysis is finally performed by using Series 1 35 and Series 4102Q diesel engines as the objects,with the results according well with those in actual situations.

Key words: diesel engine, cylinder diameter, piston stroke, optimized design, nonlinear constraint, Sequential Quadratic Programming