4) An in-line four cylinder engine has a 0, 180, 180, 0 piston configuration. The piston stroke, con-rod length and distance between each cylinder are 70 mm, 130 mm and 85 mm respectively. Further data relating to the components is as follows:- con-rod mass = : 0.45 kg combined piston/gudgeon pin mass = 0.5 kg Distance of big end to C. of G of con-rod = 0.03 m A simplified dynamics analysis is to be carried out, thus : a) For a simplified model explain why the re-design of the con-rod would help in the analysis and show how it is implemented, [5 marks] b) Taking that the piston acceleration, , to be used in the analysis is given by the expression : - d) r y = -rw (cose + cos20) give the meaning of each term and describe briefly the origin of its derivation. [6 marks] c) For an engine speed of 5500 rpm, indicate on a suitable diagram the loads developed by each cylinder/piston combination taking piston 1 to be at TDC and hence [8 marks] Calculate the out-of-balance loading on the engine at the operating speed given in part c). [6 marks]