Tests results of new diagnostic method for WOLA marine diesel engines type H

Results of studies that aim was to develop a diagnostic method for WOLA marine diesel engines type H are presented in this paper. These engines are high-speed type units used to drive small vessels or more often to drive ship generators. Polish Navy is operating significant number engines of this type. Motors of this type do not have indicator valves, which complicates the assessment of their technical condition in exploitation. These engines also, because of their age, are relatively poorly equipped in control and measurement devices. In the era of cost reduction in operation of marine equipment there is also tendency to reduce the cost of maintenance and repair of diesel engines. One way to avoid malfunction of the motor can be systematic monitoring of the technical condition of selected critical systems using reliable diagnostic methods. Polish Naval Academy (PNA) in Gdynia for years has been doing research on methods of diagnosing marine internal combustion engines. In recent years, a diagnostic method for high-speed diesel engines based on the analysis of envelope of vibration accelerations generated by the valve gear mechanism and fuel system of WOLA type H engines has been developed. Preliminary tests were carried out on a six-cylinder WOLA engine type 57H6Aa in the Marine Power Plant Operation Laboratory in PNA. Verification tests were conducted on twelve-cylinders WOLA engines of the same type on navy vessels. The developed method allows determine the angles of opening and closing the fuel injection valves and angles of closing intake and exhaust valves during engine operation. Using this method it could not be clearly determined opening angles of intake and exhaust valves.