Experimental estimation of transient contact conductance between exhaust valve and its seat

In the Internal combustion engines, generated hot gases exit through the exhaust valve lead to the valve and seat achieve high temperatures. To keep away from damage, heat is transferred from the exhaust valve to the seat as they come into contact with each other during the opening and closing cycle. Heat transfer rate from the exhaust valve to the seat and to the cooling water will be a function of the contact resistance or contact conductance between exhaust valve and seat. A few studies for transient contact conductance for this application exist in the literature. An experimental study has been made to determine TCC between two co-axial cylinders as exhaust valve and seat and also investigate the effect of pressure and contact frequency on the contact conductance. The results show that with increase of engine speed (increase of contact pressure and frequency), the contact conductance increase with the increase in contact pressure and decrease with the increase in contact frequency. The experimental results are generally well within acceptable accuracy.