Internal combustion engines are engines (or motors) in which the fuel is burnt inside the engine itself, Download book PDF The petrol engine and the diesel engine as used in modern automobiles are both internal combustion engines. Session Objectives. • To understand the classification of automotive engines. • Study the constructional features and arrangement of various parts of IC engines. Automobile Engine 4 Stroke Cycle ENGSpdf - Download as PDF File .pdf), Text File .txt) or view presentation slides online. mech topics.
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Many studies have linked the greenhouse gases produced by an automobile engine to the partial destruction of our atmosphere and to global. A heat engine is a machine, which converts heat energy into mechanical energy. case of internal combustion engine, the combustion of fuel takes place inside. We almost take our Internal Combustion Engines for granted don‟t we? All we do is download our vehicles, hop in and drive around. There is, however, a history of.
The automobile engine
Double cylinder engine: The engine which consists of two cylinders is called double cylinder engine. Multi cylinder engine: An engine which consists of more than two cylinders is called multi cylinder engine. The multi cylinder engine may have three, four, six, eight, twelve and sixteen cylinder.
Arrangement of Cylinders On the basis of arrangement of cylinders the engines classification is: i. Vertical engine: in vertical engines, the cylinders are arranged in vertical position as shown in the diagram.
Horizontal engine: In horizontal engines, the cylinders are placed horizontal position as shown in the diagram given below. Before the gas turbine engine is not become predominant, it is commonly used for aircraft engines. V-engine: In v types of engine, the cylinders are placed in two banks having some angle between them.
The angle between the two banks is keep as small as possible to prevent vibration and balancing problem.
Most mechanical devices invented during the industrial revolution were described as engines—the steam engine being a notable example. However, the original steam engines, such as those by Thomas Savery , were not mechanical engines but pumps.
In this manner, a fire engine in its original form was merely a water pump, with the engine being transported to the fire by horses.
In modern usage, the term engine typically describes devices, like steam engines and internal combustion engines, that burn or otherwise consume fuel to perform mechanical work by exerting a torque or linear force usually in the form of thrust. Devices converting heat energy into motion are commonly referred to simply as engines. Examples of engines which produce thrust include turbofans and rockets.
When the internal combustion engine was invented, the term motor was initially used to distinguish it from the steam engine—which was in wide use at the time, powering locomotives and other vehicles such as steam rollers. The term motor derives from the Latin verb moto which means to set in motion, or maintain motion.
Thus a motor is a device that imparts motion. Motor and engine are interchangeable in standard English. A heat engine may also serve as a prime mover —a component that transforms the flow or changes in pressure of a fluid into mechanical energy. Another way of looking at it is that a motor receives power from an external source, and then converts it into mechanical energy, while an engine creates power from pressure derived directly from the explosive force of combustion or other chemical reaction, or secondarily from the action of some such force on other substances such as air, water, or steam.
More complex engines using human power , animal power , water power , wind power and even steam power date back to antiquity. Human power was focused by the use of simple engines, such as the capstan , windlass or treadmill , and with ropes , pulleys , and block and tackle arrangements; this power was transmitted usually with the forces multiplied and the speed reduced.
These were used in cranes and aboard ships in Ancient Greece , as well as in mines , water pumps and siege engines in Ancient Rome. The writers of those times, including Vitruvius , Frontinus and Pliny the Elder , treat these engines as commonplace, so their invention may be more ancient. By the 1st century AD, cattle and horses were used in mills , driving machines similar to those powered by humans in earlier times.
According to Strabo , a water powered mill was built in Kaberia of the kingdom of Mithridates during the 1st century BC. Use of water wheels in mills spread throughout the Roman Empire over the next few centuries. Nose Flanks Base circle the effects of surface roughness height and distribution before after before after before after between components upon the lubrication of machine ele- 0. By incorporation of an asperity interaction model 0.
For exam- 0. The a Damage on the nose caused by run-out on cam. For the direct acting cam occur and that lubricant retention in surface troughs can be and follower situation shown in Fig. A few aspects of surface topography considera- studied the predicted effects of surface roughness upon tions in relation to cam and follower performance and nominal film thickness, power loss and load carried by the analysis will be briefly touched upon.
Whilst some interesting predictions emerge from such 3.
Initial surface roughness analysis, for example, the small proportion of the load carried by the asperities because of the non-conformal Few studies seem to have been directed to the influence nature of the camrfollower contact, it must be observed of initial surface roughness on the subsequent performance that currently the value of such analyses is limited in of automotive cams and followers.
Roylance et al. One reason undertook a study to examine wear behaviour during the for this is the use of data extrapolated beyond the film running-in period as influenced by surface topography and thickness ratio limit for which it was established. Two test apparatus were adopted, a motored Potentially of more value in the longer term, is the cylinder head and a laboratory cam and tappet machine. It was suggested that the smoothing process might not have encouraged lubricant retention in the con- tact, hence, promoting subsequent damage.
For the labora- tory apparatus, less wear was reported for smoother sur- faces and for cases where the hardness of the cam was less than that of the follower.
Different Types of Engine
Taylor w4x has reported studies using a laboratory appa- ratus to test a direct acting mechanism. The cams were steel; induction hardened to 2. Cams with different surface roughness initially were run against nominally similar followers for h at a fixed camshaft speed and tempera- ture. The data is recorded in Table 3. It can be seen that on the cam flanks, there was little change in roughness reflecting healthy oil film thickness at these sites. The cam and follower were mechanically sepa- rated over the base circle and, hence, there was no change in this region.
Over the nose region, there was evidence on the rougher cams of an improvement in surface finish reflecting removal of asperity tips and surface flattening. It will be noted that the smoother cam roughened up, and there was a tendency for the final roughness at the nose to move towards the same value irrespective of initial rough- ness.
It is worthy of note that in another series of tests the temperature of the bulk apparatus was varied up to C, but this did not appear to be an influential factor. Roughness considerations in a cam and follower w33x. Taylorr Wear — properties have been investigated.
Tanimoto et al. Such waviness was influenced by the form imposed onto the grinding wheel by the roller dresser. Wear and oil Fig. Effects of waviness orientation in EHL contacts w35x.
It was suggested that the wavy cam ness. At the present surface could offer good oil retention characteristics but time with the exponential advance in computing power, that with time the release of hard wear particles due to the and the development of increasingly more powerful nu- wave peaks could be problematical.
Automobile: Main systems
It was proposed that a merical analysis techniques, there is rapid development of cam surface having the same roughness, but zero or re- non-smooth surface, elastohydrodynamic lubrication analy- duced waviness, would show improved performance.
This has enormous significance in the design and Waviness on automotive cams remains an issue and it is development of concentrated contacts to operate under interesting to note that analysts are now in a position to increasingly severe conditions.
Ehret et al. Engine bearings tation angle, zero degrees being transverse waviness, for pure rolling and pure sliding, after Ehret et al. It is The Mobility technique for the analysis of dynamically clear that whilst the orientation of waviness is only moder- loaded engine bearings w39,40x was established some 30 ately influential upon film thickness with pure rolling, this years ago and remains the most common approach.
The is not the case for pure sliding.
Surface texture can lead to method assumes that the hydrodynamically generated load important differences and in pure sliding it is shown that capacity due to pressures in the lubricant film balances the the best lubrication condition is produced for transverse applied load, thus precluding the possibility of instability waviness.
The definitive linking of surface texture to im- effects as inertia loading is neglected. The technique has proved machine element performance in, say, a cam and proved amenable to simple computerised analysis yielding follower, would be a powerful technique. Wear prediction It is, however, important to recall that there is a wide range of assumptions implicit in the use of the Mobility The prediction of wear in machine elements is a notori- method as it is normally applied.
These include, ously difficult task. Short bearing analysis — highly inaccurate at liner contact. The same technique was first applied to the high eccentricity ratios. Circumferential symmetry — grooverhole ef- w25,26x.. It is encouraging to report that such modelling fects neglected. Rigid surfaces — manifestly not so in many wear, including the positions of maximum wear.
The circumstances. Perfect alignment — little known about misalign- and this has proved of value in developing laboratory ment issues. Newtonian lubricant behaviour — very high shear w36x. Of course, the influence of the dimensional wear rates encountered. Non vibrational instability — shaft inertia omit- the piston ringrcylinder liner contact.
Isothermal lubricant film — heat transfer effects predicting cam follower wear as influenced by material can be important. Taylorr Wear — These restrictive assumptions clearly imply that any predictions can only be benchmark and point to the impor- tance of field experience being used alongside predictions in order to make sound design prognostications for im- provements.
Taylor w4x has detailed a range of research studies in which some of the assumptions detailed above have been relaxed. In the early s, the benchmark prediction for a satisfactory minimum lubricant film thickness was about 2. Twenty-five years later, predictions of minimum film thickness a factor of 5 or more less than this are being made for engine bearings in passenger cars. A minimum film thickness in the range 0. This is one of three surface topography aspects that will be addressed in relation to automotive bearings.
Lobe size and frequency effects in engine bearings w42x. They developed an was addressed by Conway-Jones and Gojon w41x. This empirical method of calculating the asperity loading, hence, situation is being influenced by the introduction of smaller enabling heat generation to be determined on a m PV engines and, hence, smaller components such as bearings, basis, V being the surface velocity. Thus, very high maximum specific loads are being encountered in 4.
The effect of such asperity interaction would be to Mehenny et al. Evidence of this was presented by the authors There is a clear evidence that the machining process for, and is shown in Fig. With an increase in bearing say, big-end bearings may have a significant effect on temperature, the predicted torque and minimum film thick- bearing failure due to the creation of a lobed crankpin.
However, at a Experimental evidence of such lobing with any frequency predicted oil film thickness of 1. Conway-Jones and Gojon w41x dis- nominal diameter shaft. Clearly, this is large compared with predicted minimum film thickness. Mehenny et al. Comparison with some early data of DeHart and Smiley w43x, who had measured bearing weight loss due to wear with imperfect journal geometries, was encouraging.
Their evaluation revealed Fig. Surface asperity influence in engine bearings w41x. Taylorr Wear — crogroove peaks led to good conformability, lower temper- need to use scarce natural resources more efficiently and atures because of higher oil flow and resistance to seizure precipitated an intense study of the efficiency of the because of the oil retention properties.
The improved internal combustion engine: the piston assembly, valve conformability was assessed through friction measure- train and engine bearings. Such studies have remained ments, which with stepwise decreases of bearing film vibrant and have been further driven by the increasing thickness, stabilised in a much shorter time than with plain recognition of the fragility of our environment and the bearings.
This paper has reviewed the current whilst the claim to improve seizure characteristics was position regarding the tribological design and friction asso- judged by the time taken to failure when the supply of ciated with the tribological components of the engine with lubricating oil was cut off. Further references to associated a specific focus upon surface topography and surface research in this field can be found in Ref.
Much remains to be achieved in interesting to note that the use of grooving in cylinder this important field and significant areas for future atten- liners is also adopted w45x, though the orientation of the tion have been identified.
Since the attention paid to engine bearing design in the s and s, it is interesting to observe that research References in the tribology of the piston assembly and valve train has been more prevalent.
The increasingly severe operating w1x D. Dowson, History of Tribology, Professional Engineering Publish- conditions, however, are leading to an increasing propen- ing, , pp. Coy, Practical applications of lubrication models in engines, design is appropriate.
The role of surface topography New Dir. Andersson, Company perspectives in vehicle tribology — considerations alongside improved consideration of elastic Volvo, 17th Leeds—Lyon Symposium on Tribology — Vehicle and thermal effects is needed.
Tribology, Tribol. Taylor, Automobile engine tribology — design considerations 5. Dowson, Developments in lubrication — the thinning film, J. There remain extensive challenges for those interested w6x J.
Ramsbottom, On an improved piston for steam engines, Proc. The following are impor- w7x J. Ramsbottom, On the construction of packing rings for pistons, tant aspects meriting detailed research and development in Proc.It has been noted that the automobile engine, ture and lubricant availability.
For other uses, see Motor disambiguation. Thesis, w36x J. Rotary Engine http: Piston assemblies miniature capacitance film thickness transducers mounted flush in the cylinder wall to measure piston ring film In terms of overall design concept, pistons and piston thickness.
Booker, Dynamically loaded journal bearings: mobility method w25x J. HowStuffWorks The core of the engine is the cylinder, with the piston moving up and down inside the cylinder. Surface texture can lead to method assumes that the hydrodynamically generated load important differences and in pure sliding it is shown that capacity due to pressures in the lubricant film balances the the best lubrication condition is produced for transverse applied load, thus precluding the possibility of instability waviness.
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