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Exhaust manifold in engine is used to transfer the hot exhaust gas from cylinder head to the turbocharger with minimum pressure loss and to support the turbocharger assembly. This puts manifold under intense thermal and mechanical loading and makes the design very complex. While designing the manifold, resonance of the system must be avoided, and thermo-mechanical fatigue life expectations must be met. Different engine applications would call for multiple turbocharger configuration and orientations to be considered in the design layout for system level resonance assessment. This paper talks about the failure investigation of the manifold which was designed for High mount rear out (HMRO) turbo orientation and then used with high mount front out (HMFO) layout in road miller application resulted into the manifold failures.

There is a two-step migration in the Indian automotive industry from Bharat stage IV to Bharat stage VI emission norms. This emission regulatory migration demands substantial engineering efforts to design, develop and validate engine, engine components, and complete exhaust after-treatment system. In this context, cylinder bore distortion plays a vital role in engine blow-by, oil consumption, and its effect on DPF ash loading. For Bharat stage VI engines, overall thermal loading is increased which exerts higher mechanical and thermal stresses over the engine and subsequent components. Increased engine bore distortion has ill effects on the engine and after-treatment devices. Reduction of bore distortion helps piston rings to confirm with the bore, which results in low oil passing through rings towards the combustion chambers which finally results in low oil burn off in the combustion chamber.

In a bid to adopt pro-active strategies to reduce pollution, the Indian government decided to leapfrog from current emission norms to the advanced emission regulations like BS VI, CPCB4. The advancement in emission regulation is also accompanied by customer expectation of increased product performance with lower cost. Downsizing of the engines has led base engine components to experience more thermomechanical loads. Lower product cost demand of the market has pushed engineers to understand the system level interactions and identify the levers other than component design changes. Current analytical techniques provide little iteration feasibility to explore all the possible levers. This paper focuses on experimental study to understand the effect of engine operating conditions on piston and bore temperatures. Piston telemetry technique is used in capturing the real time piston temperature data with flexibility to carry out design of experiments.

Thermal fatigue crack failure is becoming the most important aspect in modern cylinder head design as modern engines are striving towards higher peak cylinder pressures. Thermal cracks are developed in the cylinder head due to thermal gradients generated because of operating conditions. Paper scope comprises analytical and experimental study on reduction of combustion deck temperature and enhancing combustion deck fatigue margin of a diesel engine through introduction of scallop on the combustion face. There are methods such as cooling jacket optimization, faceplate insertion, scallops and other measures to reduce the temperatures on the combustion deck.

For upgrading/new engine development, the piston and cylinder head are the most exposed members due to amplified mechanical and thermal loadings. Mechanical loading is basically due to the combustion gas pressure in the combustion chamber and its scale can be judged in terms of peak cylinder pressure. Thermal loading is due to temperature by heat flux acting on the piston surface, cylinder liner and the cylinder head. The importance of the various loads applied on the head and cylinder block in operation was assessed and a method of predicting their influence on the structural integrity of the components described by doing actual test on engine test bench. Therefore, it’s very important to have thermal survey of the engine. The engine thermal survey test was primarily developed to measure the temperature in the head of the engine to determine if the temperatures that are measured are within the design guidelines for appropriate engine operation.

Injector nozzle coking can severely limit engine performance by limiting the amount of fuel delivered to the combustion chamber and altering the spray pattern. Injector nozzle coking is also one of the most sensitive measures of diesel fuel quality. Formation of deposits within the holes of the injector nozzle or on the outside of the injector nozzle may have an adverse effect on overall system performance. There is no single factor that results in nozzle coking but can be classified in four major areas e.g. spray hole geometry, application duty cycle, nozzle localized temperature and the fuel quality. This paper provides a critical review of the current understanding of the main factors affecting the deposit formation. Engine was tested by motoring dynamometer using test cycle generated by Cummins Inc, as an attempt to try to simulate field conditions.

By looking current scenario, engine development lead time was reducing day by day to enter early in the competitive market and to compete as early as possible. During initial engine development phase, it was very important to know how engine operating temperatures were affecting to piston pack and related system. Conventionally temp plug method was used to capture the piston temperature, but it was time consuming, much costly, for every test condition, new temp plug pistons required, if unfortunately, any hot shutdown happened during the test, again full test needs to be restarted with new set of temp plug pistons and many more limitations. So, for Cummins engine we used Telemetry technique to measure the piston temperature ONLINE and in real time. Piston telemetry enables the telemetric transfer of piston data from internal reciprocating and rotating components. The pistons had wireless telemetry to send real time steady state and transient data from within engines.

In addition to performance target, recent stringent emission legislation and reduction in oil consumption are the major driving force for engine design and development. In this reference importance of crankcase ventilation has increased immensely and the manufacturers are bound to develop most efficient system with high oil trap efficiency. In crankcase ventilation system, the blow-by gases from the crankcase are routed to the intake manifold through Oil separator system. The oil separator task is to retain the oil part from the blow by gas and send it back to sump. Developing an oil separator for the engine studied here was very challenging considering double stage turbocharger which produces very fine mist of oil and is difficult to separate. The study shows that oil mist coming in blow by is of size 0.3 micron and lesser than it. The major contribution of these fine mists was from turbocharger.

In Current scenario all Vehicle Manufacturer are looking towards cost effectiveness in their product development without compromising product quality and performance. With this reference, development of low cost FEAD (Front End Accessory Drive) system with stretch fit belt & idlers for multiple accessories has emerged as one of the alternative smart engineering solution against the FEAD with auto tensioner. The beauty of this low cost FEAD system is not only the cost saving but also the long lasting performance without affecting component life. In the current work, development of a low cost FEAD for 3 cylinder 1.5 litre diesel engine has been presented. It was one of the challenges to introduce stretch fit belt for 3 cylinder engine considering the high torsional vibration. The performance of this FEAD system was evaluated in terms of accessories pulley slip and belt flapping. The component durability was assessed both at engine as well as at vehicle level.

The prime objective of this study is to check the friction reduction by reducing the tangential load of the piston ring. To examine this experimental study has been carried out under motored engine condition from 500 to 4000 engine speed at the step of 500 rpm at different oil temperatures ranging from 40 °C to 120 °C. 15 W40 oil was used for this study. Standard Strip down approach was followed in accessing the Friction. The whole friction measurement was split in crank train and piston group friction and was measured with base and modified piston ring pack. The modified piston ring pack was having 24% less ring tension as compared to base ring pack. The study was carried out using block, crankshaft & Piston of 100 hp, 1.5 litre, 3 cylinder engine with 92 mm stroke and 83 mm bore. In each test ring pack was tested as a part of complete piston assembly.

Connecting rod of a high performance reciprocating internal combustion engine is one of the critical components exhibiting complex motion. This is subjected to both compressive load due to combustion force as well as tensile load due to inertia of the moving components. These loadings are cyclic in nature and the component is highly prone to fatigue failure if not deigned or manufactured carefully. Therefore connecting rods are designed and manufactured with high degree of precision for infinite loading cycle. But failures in connecting rod is often reported which is associated to either fatigue, bending, bearing failure or assembly faults. This study deals with one of such failure of connecting rod reported during fatigue testing. Failures occurred at around 1 million fatigue loading cycle as against target life of 5 million cycles. The present study represents the investigations done for engine connecting rod and with a view to identify the root cause of failure.

Current high rating thermal loaded engines must have super-efficient lubrication system to provide clean oil at appropriate pressure and appropriate lube oil temperature to every part of the engine at all engine RPM speeds and loads. So oil pump not only have to satisfy above parameters but also it should be durable till engine life. Gerotor pumps are internal rotary positive-displacement pumps in which the outer rotor has one tooth more than the inner rotor. The gear profiles have a cycloidal shape. Both are meshed in conjugate to each other. Gerotor takes up engine power through crankshaft and deliver to various engine consumers at required pressure and required time. Over the complete engine rpm speed and loads range, oil pump need to perform efficiently to provide proper functioning of the engine. Otherwise low oil pressure leads to more friction in the pump, seizure of bearings and final failure of the engine .High oil pressure can lead to failure in oil filter, gaskets and seal.