Knocking and detonation in ic engines pdf files

Detonationpre ignition and the outboard motor one of the most common causes of major internal engine damage results from the abnormal combustion conditions that have plagued the internal combustion engine since its beginning, namely detonation and preignition, or surface ignition. Effect of knocking in spark ignition in a fourstroke engine authors ravikant sahu1, eklabya gupta2. Likewise there is a wide range of ways to classify internalcombustion engines, some of which are listed below. In a properly functioning engine, the charge burns with the flame front progressing smoothly from the point of ignition across the combustion chamber. Reciprocating engines include both diesel and spark ignition configurations. Engine knock, or detonation, occurs when the temperature or pressure in the. It is caused due to the propagation of a high speed pressure wave created by the autoignition of end portion of unburnt fuel. In addition to this knocking puts a limit on the compression ratio at which an.

Mathematical modeling of knocking combustion and created. Detonation, or engine knock, occurs simply when fuel preignites. Knocking, in an internalcombustion engine, sharp sounds caused by premature combustion of part of the compressed airfuel mixture in the cylinder. Text andor other creative content from engine knocking was copied or moved into preignition with this edit on march 11, 2018. These were then downloaded as tiff files where each image. Acces pdf ic engine by r yadav ic engine by r yadav recognizing the habit ways to get this book ic engine by r yadav is additionally useful. American technical publishers orland park, illinois. If you dont understand exactly what each of these events are and how they occur, you wont know how to prevent them from happening, or possibly even recognizing when it happens. Onepiece valves are commonly used on engines that drive lighter loads, have. Prolonged and intense knocking can break the piston or the engine, though it is can also endure this slight issue for thousands of miles. It the temperature of intake air in ic engines is lowered, then its efficiency will a increase b decrease.

The effect of strokebore ratio on engine friction and economy is very small. Ic engine most important mcq questions with answers most important mechanical engineering mcq on ic engine. We use your linkedin profile and activity data to personalize ads and to show you more relevant ads. Most oem knock sensors are basically microphones tuned to listen for a specific. Detonation or knocking in ic engines mechanical engineering. There is a wide range of internal combustion engines corresponding to their many varied applications.

Knock prevention and increase of reliability and efficiency of high. The airfuel charge is meant to be ignited by the spark plug only, and at a specified time during the normal cycle of the piston. We get asked this question a lot, and rightfully so. Engines objective questions and answers pdf,interview questions,multiple choice questions,lab viva,seminar topics,online quiz important free download.

Knock onset, knock intensity, superknock and preignition in spark. Knocking combustion causes major engine damage, and also reduces the efficiency. High strokebore ratio engines have equally good friction mep values as that for low strokebore ratio engine. Knocking combustion in sparkignition engines article pdf available in progress in energy and combustion science 61. Detonation occurs when the pressure and temperature inside the cylinder become higher than the critical pressure and temperature of the fuel.

The air motion so organized inside the combustion chamber and the turbulence of the air passes across the fuel jet tears it into fine particles. Powerpoint slide on knocking in ic engines compiled by raja hossain. Study of knocking effect in compression ignition engine. Preignition decreases performance and results in an audible pinging or knocking sound in the engine.

Ill add a couple of thoughts that come to mind when i think about knocking and detonation. These are respectively, the suction, compression, power and exhaust strokes. The most important works that carried out theoretical. Knocking and detonation are not what you want occurring in your engine 2. You have remained in right site to start getting this info. The resulting knock or ping is the sound of the pistons slamming against the cylinder walls. Knocking also called knock, detonation or spark knock, pinking in uk english or pinging in us english in sparkignition internal combustion engines occurs when combustion of the airfuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of airfuel mixture explode outside the envelope of the normal combustion front. They are important for both transportation and for stationary uses. The usage of hydrogen in compression ignition engine leads to production of knocking or detonation because of its lower ignition energy, wider flammability range, and shorter quenching distance. Worldwide production for reciprocating internal combustion engines is over 200 million units per year. Read pdf ic engine m l mathur ic engine m l mathur how to change your vehicles serpentine belt, tensioner, and idler pulley proper belt tension is critical. Both spark ignition and compression ignition engines are covered, as are those operating on fourstroke and twostroke cycles, and ranging in size from small model airplane engines to the largest stationary engines. As the flame propagates across combustion chamber, end gas is compressed causing pressure, temperature and density to increase. Compression ratio is increased when a large volume of combustion chamber deposits accumulate in the engine.

Similarly, overheating may cause additional wearandtear on the engine, be relatively harmless or cause the engine to catch on fire and break. The two chemical drops normally used are, ethyl nitrate 33gmsus gallon 29gmsus gallon amyl nitrate higher the. Reason, factors, comparison, gate mechanical lectures knocking, detonation. The causes of internal engine knock, and how to eliminate it.

There are different types of ic engines that can be classified on the following basis. The noise which gives the name of knocking to detonation is like. Internal combustion engines can be classified internal combustion engines ca n be classified n be classified as c as cas continuous ic engines and ontinuous ic engines and. The causes of internal engine knock, and how to eliminate. Some engines, such as liquid cooled 2stroke engines found in snowmobiles, watercraft and motorcycles, have a very common detonation failure mode. Detonation and knocking 80 theories of detonation 82 effect of engine variables on knock 83. Fourstroke cycle diesel engine in fourstroke cycle engines there are four strokes completing two revolutions of the crankshaft. Phenomenon of diesel knock knocking is violet gas vibration and audible sound. Knocking and detonation is physically same like nosiy sound. What is the difference between knocking and detonation in ic engine.

Pdf ic engines pdf ic engines pdf ic engines download. Effect of knocking in spark ignition in a fourstroke engine. Pdf knocking combustion in sparkignition engines researchgate. Internal combustion engines are classified as follows.

Knocking also knock, detonation, spark knock, pinging or pinking in spark ignition internal combustion engines occurs when combustion of some of the airfuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but one or more pockets of airfuel mixture explode outside the envelope of the normal combustion front. Main trends in detonation engine development are discussed. Internal combustion enginel is a fair summary of the opinions existing at the present time. Under normal conditions, the combusting air and fuel mixture inside the combustion chamber ignites in a controlled manner. Reciprocating internal combustion engines are a well established and widely used technology. Internal combustion engine terminology and abbreviations the following terms and abbreviations are commonly used in engine technology literature. External combustion engines are those in which combustion takes place outside the engine where as ic engines takes place outside the engine where as ic engines combustion takes place with in the engine. This video explains knocking combustion and preignition and the reasons for this irregular combustion. Recently, i saw this question, which included a rather alarming quote. Sae high efficiency ic engine symposium held 10 11 april 2011 in detroit, mi, usa while these forums focused primarily on transportation engines, the general conclusions reached are applicable to all ic engines participants in the 2010 engine efficiency colloquium 2010 engine efficiency colloquium final report edited by daw, et al.

Internal combustion engine handbook sae international. The high velocity knock, usually called detonation,will produce severe damage of the engine and is avoided by the electronic engine control. Engines the loud pulsating noise heard within the engine cylinder of an i. Full throttle operation with carburetor heat on can cause detonation. The effect of knocking in piston and piston cylinder is crack and defect in piston head as shown in fig. He expressed that the knock phenomenon is similar to detonation of a. The effects of detonation may be anywhere from arbitrary to severe.

Ic internal combustion engines lecture note pdf notes download for the undergraduate course and an exhaust manifold generally of cast iron complete the engine assembly. Detonation means the sudden and violent knocks experienced in an internal combustion engine by engineering means, this knock is set up by a highpressure wave giving loud pulsating noise this occurs when it strikes against cylinder walls, cylinder head, and piston. What is the difference between knocking and detonation in. The mixture is ignited by the spark, normally in the centre of the cylinder, and a flame front moves from the spark towards the outside of the cylinder in a controlled burn. What is the difference between knocking and detonation. Knock pinging is the actual noise that can be audibly heard if detonation is bad enough. What typically happens is that when detonation occurs the piston expands excessively, scurfs in the bore along those four spots and wipes material into the. I c engines full notes, pdfs, lecture notes download.

The former pages history now serves to provide attribution for that content in the latter page, and it must not be deleted so long as the latter page exists. As the premixed flame develops earlier in a preignition cycle, autoignition of the endgas. It was found that detonation can occur in modern internal combustion engines under high energy density conditions. Internal combustion ie spark ignition 81 an engine in which the combustion process in each cycle is started by use of a spark plug. Preignition is an uncontrolled combustion event which occurs before the spark event. Composition factor the detonation or knocking in ci engine can be reduced by using certain fuel additives which would increase the cetane number of the fuel. Phenomenon of knock in ci engine is called knocking and phenomenon of knock in petrol engine is called detonation. Detonation is an uncontrolled combustion event which occurs after the spark event. Modern methods in engine knock signal detection sciencedirect.