Abstract
Keywords:
Engine Component, Parts, Diesel Engine, Cylinder Head Gasket, Seal, Experiment, Dynamic Characteristics, Torque, Temperature, Load, Surface Pressure, Gas Leak
Abstract
The cylinder head and the cylinder block of high speed diesel engines for automobiles have lost their rigidity because of weight reduction, utilizing aluminum material and thinner wall thickness. Moreover, both higher output engines and highly turbo charged engines caused gas leakage of the cylinder head gasket through unbalanced sealing conditions. However, the gasket should not leak and should have the durability under high output and highly turbo charged conditions. Then, the dynamic characteristics of the cylinder head gaskets for diesel engines must be clarified from the analytical and experimental standpoints. Experiments on a small, one-cylinder diesel engine were performed by changing the temperature of cooling water, and also by reducing the tightening torque of the cylinder head bolts. Three kinds of test cylinder head gaskets were made by varying the material and the configuration of the cylinder head gaskets. The ambient temperatures at several points of each cylinder head gasket and in its peripheral region were measured in heating and cooling temperature cycle by abrupt change of water during steady operation. The relative displacements between cylinder head and cylinder block, the loads of the cylinder head bolts and the indicator diagram were also measured in the same way. The effect of the temperature differences among the cylinder head, cylinder block and head bolts both on the loads of the head bolts and on the relative displacements were observed by the above-mentioned experiments for the test gaskets. Moreover, the gas leakage was observed by utilizing a leakage detective device during engine running on the condition of reduction of the tightening torque. The sealing characteristics both in the transient state and in the steady state of the cooling water temperature were investigated from an experimental standpoint. The investigation on the gas sealing characteristics in the transient and steady states is the main purpose of this experimental study.