TREND OF OVALITY, TENSION, CLOSED GAP & ANALYSIS OF CPC THICKNESS, BARREL PEAK IN CASE OF PROFILE GRINDING AND THEIR FURTHER IMPROVEMENT

Mechanical Engineering

Now a day’s various methods are in use on cylinder piston group for improving service life of IC Engine for reducing exhaust emission and improving engine performance. The wear resistance of thermal sprayed molybdenum applicable to the piston ring will be studied in this review. Wear resistance of molybdenum coated piston ring is high as compared to ordinary cast iron rings. Experiments on life cycle is to be performed on the compressed natural gas engine as per IS Standard for specified operating parameters. Oil lubricity test done on oil sample would give measure of wear. And wear effect on piston ring is investigated based on performance parameters like Brake specific fuel consumption, Brake power, exhaust gas temperature, Brake thermal efficiency and exhaust emissions like NOx, CO, HC, and O2. Results will be compared for both coating and non-coating condition. So by reviewing research on effect of piston ring coating, we can improve the performance of SI Engine Internal Combustion Engine is a device in which heat is generated as a result of combustion process .This heat of combustion product is used to produce the work. To produce the work, the combustion is carried out in such a way that high pressure combustion product would be expanded through the piston. So engine life depends mainly on the part of the engine. So consequently service life of the engine can be increased by considering the part which dominates its major role in the working condition of the engine. The split piston ring was invented by John Ramsbottom who reported the benefits to the Institution of Mechanical Engineers in 1854. It soon replaced the hemp packing hitherto used in steam engines. The use of piston rings at once dramatically reduced the frictional resistance, the leakage of stream, and the mass of the piston, leading to significant increase in power and efficiency and longer maintenance intervals. Most automotive pistons have three rings: The top two while also controlling oil are primarily for compression sealing (compression rings); the lower ring is for controlling the supply of oil to the liner which lubricates the piston skirt and the compression rings (oil control rings). At least two piston rings are found on most piston and cylinder combination. Typical compression ring designs will have an essentially rectangular cross section or a keystone (right angled trapezoidal) cross section. The periphery will then have either a barrel profile (top compression rings) or a taper napier form (second compression rings or scraper rings). There are some taper faced top rings and on some old engines simple plain faced rings were used. The piston might be a fairly loose fit in the cylinder. If it were a tight fit, it would expand as it got hot and might stick tight in the cylinder. If a piston sticks (seizes) it could cause serious damage to the engine. On the other hand, if there is too much clearance between the piston and cylinder walls, much of the pressure from the burning gasoline vapour will leak past the piston (a condition known as blow-by) and into the crankcase, and the push on the piston from combustion will be much less effective in delivering power. Piston rings for current internal combustion engines have to meet all the requirements of a dynamic seal for linear motion that operates under demanding thermal and chemical conditions. In short, the following requirements for piston rings can be identified: Low friction for supporting the high power efficiency rate. Low wear of the ring, for ensuring a long operational lifetime. Low wear of the cylinder liner, for retaining the desired surface texture of the liner. Emission suppression, by limiting the flow of engine oil to the combustion chamber. Good sealing capability and low blow-by for supporting the power efficiency rate. Good resistance against mechanothermal fatigue, chemical attacks and hot erosion. Reliable operation and cost effectiveness for a significantly long time. REVIEW ON PISTON RING COATING A. Marcus Kennedy (2012) studied on Piston ring coating reduces gasoline engine friction and developed a coating system for piston rings under the name of Carboglide which decreases wear in highly charged gasoline engines and further reduces friction losses which occur between the ring pack and the cylinder running surface. The tailored composition of the specific layer structure of the carbon-based Carboglide coating in combination with corresponding modified piston ring designs yields a potential to improve fuel efficiency by up to 1.5 %. Piston Ring coating combines extremely low friction values with high strength and durability of piston rings and cylinder running surfaces. By using this coating, the ring pack’s frictional losses can be reduced by up to 20 %. It signifi cantly protects the cylinder run- ning surface against scoring, increased wear and scuffing during inadequate lubrication. Carboglide makes a substan- tial contribution to the development of high performance gasoline engines with even better fuel economy by up to 1.5 % with consequently lowering CO2 emissions. B. Yucong Wang (1999)Studied on Scuffing and wear behavior of aluminum piston skirt coatings against aluminum cylinder bore. Various coatings, especially nickel based ceramic composite.

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