TECHNOLOGY TRENDS

IC Engine Condition Monitoring Instrument
(By Captain V.K.Agarwal and Rahul Pandit)

• Preamble

Since the advent of steam engineers have been using mechanical indicator for measuring the horsepower of various cylinders. The curves obtained depicted the health of the engine and horsepower could be calculated by using a Planimeter. This helped in fine tuning the system by making adjustments to various sub-systems. The same principle was followed when diesel engine made its way into marine world. Over the years the engineers at sea struggled string, pulley and planimeter, to achieve desired results of the steam as well as diesel engines, in the orthodox way. Sometime this important process was skipped in the need of more important engagements, since it was time consuming as well as laborious.

• Electronic Indicator
  
  In order to simplify the system and make it more efficient, electronic devices are now available in the market, which not only make the process easy but also gives quicker and reliable results. Such devices are fore runner to the emerging technology of future. The instrument records combustion characteristics and internal parameters of each cylinder of an engine, which can then be used for analyzing the internal condition of each unit. The result thus obtained is used to fine tune the engine for optimizing the engine output.

• Methodology
  
  The instrument is very simple to use. It is fitted on top of cylinder head on the indicator cock, which records variation of cylinder pressure, with the help of an internally fitted diaphragm, in relation to the crank angle. Electronic circuit measures the amplitude of the diaphragm and the crank angle is measured by a sensor fitted on a bracket adjacent to the flywheel or any other rotating component, representing true RPM of the engine in relation to piston movement. This pressure and crank angle relationship is set in the memory and desired results are calculated with the help of in-built software.

• Result
  
  The data is converted into accurate pressure curve, which gives valuable information on engine condition. This can be analyzed and conclusion drawn to judge the condition of engine, unit by unit. The graphs and readings can also be compared to the previous results or established bench marks, if available, for assessment of condition. The records can be kept as historical record for future comparison. Ideally the instrument is used on newly built engines for testing and to set benchmark, after periodic overhauls and in service periodically to check the Health State of the engine.