THE SYSTEMS OF FEEDING IN THE DIESEL ENGINES
In the diesel engines the feeding is made separately introducing, inside the cylinders, the air that in the time of compression 600º C reaches, and the fuel that is injected to high pressure, which are mixed inside the combustion chamber, where the combustion of this mixture takes place.
For the good operation of the electrical set of the automobile a series of electrical systems is necessary that fulfill very concrete and specific missions.
The set of elements that has the mission to make arrive the turn from the motor until the driving wheels, denominates transmission system quarters car With this system also is able to vary the relation of transmission between the crank and the wheels. This relation is varied based on the circumstances of the moment (transported load and the layout of the road). According to as the transmission relation takes part, the output axis of the box of speeds (secondary axis), can turn to the same revolutions, to more or unless the crank. If the power shaft turns more slowly than the crank, we will say that a reduction ratio or reduction has taken place and in opposite case a multiplication or super-march. In a system of total propulsion for trucks imagines. When gearing down the revolutions in the secondary one, a proportional increase of the pair of same exit in the secondary one takes place. For example: If the crank turns to 1000 r.p.m. and the 500 power shaft does to r.p.m., have geared down the revolutions of the secondary one, but we have increased to the double the initial value of the pair of exit, that is to say, there are lost speed but we have gained force. The rule of the mechanics is fulfilled “which is lost in speed gains in force and to the inverse one”. The disposition of the elements of the transmission system will depend on the relative situation that exists between the motor and the driving wheels. Types of transmission? Front motor and traction Their front wheels are motor and directives and do not have power shaft. This system very is used in tourism of small and medium power. In the figure this disposition imagines in which it is the motor, the clutch, the box of speeds and the group reducing-differential. Front motor and propulsion the driving wheels are the back, and has power shaft. Its disposition is something more complex, being used in trucks and tourism of great powers. In the figure this disposition imagines in which it is the motor, the clutch, the box of speeds, the power shaft and the axis reducing-differential. Back motor and propulsion Their driving wheels are the back and it does not have power shaft either. This system as soon as one is used at the present time by problems of refrigeration of the motor. In the figure this disposition imagines in which it is the motor, the clutch, the box of speeds and the group reducing-differential. Double propulsion Used in trucks of great tonnage, where most of the weight is supported by the back wheels and better distributed. This system consists of placing two motor back bridges and thus avoiding to place a single conical group of great dimensions. This way the effort to transmit by each conical group is mainly reduced to half, being reduced the dimensions those of the pair-conical one. Total transmission Both axes of the vehicle are motor. Both bridges or motor axes take to a differential each one. With this transmission they can, voluntarily of the conductor, to both send the movement to bridges or only to the buttock. This system frequently mounts in vehicles all land (4 WD) and in trucks of great tonnages mainly those that dedicate to the construction and public works. Elements of the system of transmission to describe the transmission elements, we considered a vehicle with front motor and propulsion since in the this assembly it uses all the elements of the transmission system: or It engages the clutch: it must like mission connect or disconnect, voluntarily of the conductor, the movement of the motor to the rest of the transmission system. or Box of speeds: she is the one in charge to increase, to maintain or to diminish the relation of transmission between the crank and the wheels, based on the necessities, with the purpose of taking advantage of to the maximum the engine power. or power Shaft: conical-differential transmits the movement of the box of speeds to the even set. or pair-conical Mechanism differential: it maintains constant the sum of the speeds that take the driving wheels before taking the curve. It constantly gears down the returns of the power shaft in the driving wheels and turns the longitudinal turn of this one, in cross-sectional turn in the wheels. or Meetings of transmission: the meetings are used to unite transmission elements and to allow to variations of length and positions. or Semiárboles of transmission (palieres): they are the ones in charge to transmit the movement of the group conical-differential until the driving wheels, when the system lacks power shaft. Clutch It has the mission to connect and to disconnect, voluntarily of the conductor, the turn of the motor of the gear box. It must transmit the movement of a smooth and progressive form, without pulls take place that can produce breakage in some elements of the transmission system. One is located between the steering wheel of inertia (flying motor) and the box of speeds. Within the great variety of existing clutches, they are possible to emphasize the following ones: or Clutches of friction. or hydraulic Clutches. or electromagnetic Clutches? Clutch of friction monodisc of wharves the disc clutch is constituted by the following elements: or Disc of lead clutch or, that transmits the movement by means of striae to the primary one of the gear box. or Plate or disc of pressure, that is dragged in its turn by the housing and is pushed towards the steering wheel by the wharves. or Housing, together with the steering wheel by means of screws. or Collarín of clutch, formed by a top of graphite and washer of pressure or by a bearing of push. or Bracket of disengagement, that driven by the conductor, it pushes collarín. or Sideburns or handle of disengagement, that throws of the plate of pressure or Wharves of compression, placed between housing and plate of pressure. Disc of clutch This disc, also denominated lead disc, is mounted in the fluted one of the primary one of the gear box, and is located between the motor steering wheel and the disc of pressure. This element is constituted by a steel disc with radial cuts. The disc goes united to a bucket through helical wharves, making the elastic union between both elements, cushioning the oscillations of the disc when it makes contact with enemy with the inertia steering wheel. The bucket is fluted and it will be reconciled in the end of the primary axis of the box of speeds. The end of the primary one, also has fluting for its union with the striae of the bucket, of the disc. To both sides of the disc trimmings of a material fibrous, with a high coefficient of friction, adherent, and strongly very resistant are placed to the heat and the wearing down by friction. One of the faces of the lead disc makes contact with enemy with the inertia steering wheel and transmits the clutch turn. The other face of the lead disc makes contact with enemy with the pressure plate doing to turn all the set. The diameter of the clutch disc depends on the power to transmit, that is to say, to greater power to transmit greater diameter of clutch disc. Plate of pressure is formed by a steel disc fused in form of circular crown, that goes united to the housing by means of the wharves of the mechanisms of pressure and to the handles, having made an axial displacement during the drive of the clutch pedal, when it is wanted to throw the clutch out or to engage the clutch. It is located between the disc of clutch and the housing. Through the pressure mechanisms, it strongly pushes the disc of clutch against the inertia steering wheel, being this disc pressed between the motor steering wheel and the disc of pressure and transmitting the movement to the primary axis without slips. The handles will retire to the pressure disc when the pedal of the clutch is stepped on. Some types of clutch take only a central wharf instead of several placed in the periphery and on the disc of pressure and others, that are used in tourism, they take a diaphragm, as it is seen in this chapter. Housing It is the outer piece that covers all the set with clutch. It holds to the handles and wharves to the pressure disc, forming all it a single set. The housing is united by the screws in the orifices to the steering wheel of inertia of shared in common form. 0 Operation The normal situation of “an engaged” clutch is the one of, loose pedal, in which the movement of the crank is transmitted complete to the lead disc and the primary axis of the gear box. 1 In this situation, the disc lead or of clutch, is imprisoned between the steering wheel and the plate of pressure by the action of the wharves. When the conductor steps on the clutch pedal, the movement is not transmitted to the primary one and it says that “it is thrown the clutch out”. 2 The effort and movement of the conductor arrive at the bracket that it pushes collarín and this one to the handles which they overcome the wharves, retiring to the plate of pressure and releasing therefore the disc that are left between the steering wheel and plate of pressure comfortable, without transmitting movement to the primary one to be disconnect? Clutch of friction monodisc of diaphragm Is a friction clutch which, has like mechanism of pressure and control, an elastic diaphragm that makes the function of wharf and exerts its pressure on the disc. This diaphragm has conical form and has radial cuts, that act as well of handle. 3 It is used at the present time by his simplicity and effectiveness. Engaged operation the operation is just as in the previous case, being the diaphragm the one that it presses to the plate of pressure to the disc lead against the steering wheel of inertia of the motor. 4 Thrown the clutch out When being above the clutch pedal, the bracket pushes collarín, which presses on the center of the diaphragm, investing the coning and dragging with himself the pressure plate. The clutch disc is frees, without no force of pressure against the inertia steering wheel. Clutch of friction of two discs This system of clutch is used when the force to transmit is very great and with a single disc it is not possible to transmit all the engine power. A plate of located additional drag between both discs is formed by two discs, whose total surface of adhesion is equivalent to which it would be needed with a single disc, using. 6 The operation is equal to the normal clutches. The pressure also transmits by means of the wharves or diaphragm, although the route of collarín is greater and the system of more powerful pressure, in order that the thrown the clutch out one is made in both discs? Clutch in oil bath This multiple clutch of discs and laminae is used in motorcycles. The discs turn lubricated in oil. These humid clutches work with smoothness and undergo little wearing down? Mechanical automatic clutches the used automatic clutches in means automobiles so large, carry out all the process during the starting and in the changes of marches, of an automatic form. They do not take clutch pedal and they are used generally with boxes of speeds of automatic change. The most used they are: Automatic clutch of counterbalance does not take drive pedal, either bracket nor collarín. The engaged and unclutched action of trusts to counterbalances, that the revolutions act by the action of the centrifugal force when increasing of the motor. 7 This system allows to make a process of very progressive connection, because the pressure exerted on the disc is based on the regime of revolutions of the motor. It is not used frequently. Automatic clutch of cone and rollers These clutches usually mount, generally, with automatic gear box. In some cases they take to connections a clutch monodisc when it uses boxes of nonautomatic speeds. 8 It also acts by centrifugal force. The centrifugal element consists of rollers that slide by a zone of conical surface. In the 8, for one better compression, indicates the positions of the rollers during the disengagement (superior half) and engages the clutch (inferior half of the figure), that will depend on the revolutions of the motor? Semiautomatic clutch With the semiautomatic clutches is able to save effort to the conductor. It is an intermediate model between normal clutch and one automatic one. It tightens of the conductive plate against the steering wheel, instead of taking control of powerful means as the disc clutch, becomes by revolving counterbalances on bearings of needles in the ends of the disengagement handles. It takes to less powerful means but and collarín for his drive. 9 The advantage that presents/displays is very small during the disengagement; note when initiating the march with the motor to slow motion to solely put the first speed. In the rest of the changes, the motor is not to slow motion, reason why the conductor, to throw the clutch out, must overcome the means and the centrifugal force of the counterbalances. These clutches little are used at the present time? Hydraulic clutches East engages hydraulic engineer is used with automatic or semiautomatic gear box. It uses, for his operation, a fluid generally oil, and one is based on the transmission of hydraulic energy of a centrifugal pump to a receiving turbine. They also denominate turboembragues. 0 In order to include/understand well this principle we left as opposed to from the example of two ventilators, placed one the other. The ventilator, connected to the network, moves the air and it projects like impeller or pump on the other ventilator that is without connecting. This one last one, when receiving the air, is put to turn like a receiving turbine. Constituted constitution This, as it can be seen in the 1, by two revolving crowns and and is provided with flat partitions called blades. One of them, called motor crown, goes united to the motor tree and constitutes the centrifugal pump; the other, together with the primary one of the gear box constitutes the turbine or crowns dragged. 1 Both crowns go lodged in a watertight housing and are in favor separated of a small space so that friction among them does not take place. The trajectory that takes the liquid, (tórico eddy) imagines in the same figure. Operation Slow motion. The pump, that goes connected to the motor steering wheel, in front of is the turbine, of which it separates a small space. When the motor tour to slow motion, the centrifugal force of is insufficient so that the oil rotates the turbine and, therefore, the car does not move. 2 Average regime of revolutions When increasing the engine speed, the centrifugal force of, projects the oil against the turbine and transmits certain effort of torsion. But there is a great sliding in the set: the output axis, turns, therefore, much more slowly that the one of entrance. A great slip exists. 3 High regime of revolutions to divide of motor a certain regime del, the speed del oil is sufficient to communicate all the energy. In this case the transmission is almost direct, which allows the output axis to turn almost to a 98 percent of the regime of the input axis. 4 Slip practically does not exist. Advantages These clutches have the following advantages: or Absence of wearing downs. or Long useful duration on watch (oil change each 20,000 km). or Starting and very smooth operation. Disadvantages the disadvantages that present/display these clutches, must to a greater consumption of fuel and to greater cost of acquisition, not being able to use for box of speeds of manual change? Electromagnetic clutch the operation of the electromagnetic clutch is based on the action of a magnetic field, created by a powerful electromagnet, mounted in the inertia steering wheel. The electromagnet makes the function of pressure plate and acts on an armor that is united to primary of the box of speed, doing the lead disc function or disc of clutch. The turn of this armor will take place when the magnetic field is created, rotating to the armor by attraction, without existing this way no type of friction. In order to reinforce the action of the magnetic field, in the air gap there is magnetic dust, with particles of steel, chromium and aluminum. 5 During the operation the power supply of the electromagnet through a series of relays is controlled, actions according to the moment, by the switch of ignition, the accelerator pedal and the pedal of the clutch. Working the motor to the slow motion, the created magnetic field is little powerful and the armor of the primary axis cannot be dragged. When being above the accelerator, the created magnetic field is more powerful and the armor of primary axis is dragged. The clutch pedal does not carry out any mechanical drive on the clutch, making its action during the disengagement, annulling the power supply on the electromagnet. This way, the armor of the primary axis is frees of the magnetic field that moved it. This clutch has very high a life utility due to the absence of frictions. It does not have regulation and he is very smooth? Control system of the clutches the control system has the mission to transmit the movement exerted in the clutch pedal until the bracket and collarín. One is used for the drive of clutches that are not automatic or electromagnetic. The following types are used: or Drive by mechanical joint or mechanical system. or System of hydraulic drive or hydraulic system. or System of pneumatic drive or pneumatic system. Mechanical system Consists of uniting through a cable or a rod, the pedal with the bracket of collarín. They use small and medium tourism, due to the little effort that there is to make. 6 Hydraulic system very is used east system when the clutch is remote of the pedal and the effort to make for its drive is concerted. This system places a pump, whose piston is driven by the clutch pedal. The union between the pump and the bowler is made through a pipe of connection and between the bowler and the bracket by means of the rod. With this system the effort of drive, exerted by the conductor is multiplied, in the clutch pedal. 7 Pneumatic system East system is used when the clutch is remote of the pedal and when the effort to make for its drive is concerted. It is used in heavy vehicles, taking advantage of the installation the air brakes, although little it is used. The force that the compressed air has, exerts on a piston together with the bracket of collarín, a effort that allows the disengagement. 8 The clutch pedal controls, through the valves, the passage of the compressed air from calderín of storage, to the push piston. Box of speeds? Function of the box of speeds the mission of the gear box is to turn the motor pair. It is, then, a converter or transformer of pair. A vehicle advances when it overcomes a series of forces that are against their movement, and which they constitute the resistant pair. The motor pair and the resistant one are opposed. The function of the gear box consists of varying the motor pair between the motor and the wheels, according to the importance of the resistant pair, with the particularitity of being able to take part at any moment and to obtain the displacement of the vehicle in the best conditions? Types of gear box Manual gear boxes Are the used ones in most of the series automobiles, by their simplicity and economy. It is driven manually by means of a gearshift. We can consider three fundamental parts in its constitution: Box or case: where they go mounted the combinations of axes and gears. It takes viscous oil (SAE 80 highly: valvulinas). Train of gears: set of axes and pinions for the transmission of the movement. Control of the change: mechanism that serves to select the suitable march. We studied three types of manual gear boxes: Box manual of taking variable sliding At the moment boxes of speeds of taking variable as soon as they are used, because they have been moved by those of constant taking, that present/display the gears carved with helical teeth, allowing that the pinions of the primary or intermediary and secondary axis are always in contact with the enemy. Those of variable taking, to the being the straight teeth, have more wearing down and produce more noise. The handle has so many positions as speeds, plus the one of deadlock. Constitution 9 It is formed by a housing, within which there are three main axes: or the primary one. He is the one that receives the movement of the motor through the clutch by means of fluting that takes in its end. or the intermediary. He is formed by a series of pinions, of diameter more and more small, that are fixed to this axis. or the secondary one. One mounts after the primary one and one leans in this one. On the secondary one they go mounted another series of pinions that can be moved throughout striae, but that turn with him. Its size is of minor to greater diameter. A small axis with its pinion connected to smallest of the intermediary for the reverse gear (investing of march). The pinions of the secondary one move on the grooves by means of brackets that the conductor with the gearshift handles. Manual gear box of quiet normal constant taking Is this one a assembly that allows the use us of helical pinions. The helical pinions are characterized by the impossibility of being geared being in movement. It is precise, therefore, that they are in constant taking. When existing different relations from gears are necessary that the pinions of the secondary tree turn free on this tree. To the being a free necessity turning the pinions in the secondary tree, to make the transmission is precise to fix the corresponding pinion with the secondary tree. This fixation can be made, as it shows the 0, by means of a sliding bushing, that has mechanized a frontal dentated crown that, when moving towards the pinion, it gears with another mechanized similar crown in this last one, or by means of synchronizers. Operation We have in the 1 the different chains kinematics corresponding to the different speeds. The arrows indicate the transmission of the movement for each position. 1 As we see, this transmission is made: or For the intermediate speeds, 1ª, 2ª and 3ª, when directing the sliding bushings towards the pinions corresponding to these speeds of the secondary tree. or For the direct taking, when directing the bushing towards the pinion of the primary tree. or For the reverse gear the investing pinion of straight teeth moves. Manual gear box synchronous of constant taking simplified Very employee at the present time, since there is great amount of vehicles of front traction. The front tractions are used by their mechanical simplicity and its economy of elements (they do not have power shaft). The secondary one of the gear box directly goes to the conical group differential and, in addition, it lacks intermediary axis by which the movement is transmitted of the primary one to the secondary one by means of synchronizers. In the secondary axis it goes mounted the pinion of attack of the conical group. Usually they make with a multiplying march of the revolutions of the motor (overdrive), that is very economic. The gear box of sliding, described previously, has the disadvantage of which the passage from a speed to another one is noisy by the shock of the teeth between the pinions that are going to gear. This happens because the speeds of the pinions that are to be reconciled are unequal. In order to avoid this noise and it wears away of the gears, has resorted to the use of synchronous boxes of constant taking. The quiet one, since it has been seen previously, consists of having in constant taking the intermediary with the pinions of the secondary one, with the particularitity to be mounted crazy on him. When it is wanted to obtain a speed, a bucket that goes on striae in the secondary one moves until fitting by means of projections in the crazy pinion, thus being together with the secondary one and obtaining a speed. With this connection in constant taking, the noises are not eliminated either completely when carrying out the changes, since the speeds of the sliding bucket and the crazy pinion are not equal. For that reason one resorts to the synchronous changes that allow to equal at the moment of the change the speeds of rotation of the buckets or sliding pinions with those of the crazy pinions. Thus, the taking of contact and gear are made smoothly, without shocks nor noises. 2 Synchronizer Sliding of the crazy synchronizer and pinions of the secondary one they have its faces trunkated cone inverted, concave in sliding and the convex ones in the crazy pinion. To these cones it is called “synchronization cones to them”. It takes a locking device to fix the position of the sliding one. 3 Operation Once unclutched the motor, with the gearshift, it is acted on sliding the corresponding one to the speed that is wanted to obtain. First that makes contact with enemy are the trunkated cone surfaces of both pinions, (sliding To and the C), equaling its speeds. Immediately afterwards the outer body moves, overcoming the fastener of wharf and ball, until being reconciled to the gear of the crazy pinion. 4 The movement takes place in two times; one of taking of contact of the cones (To and C) to equal speeds and other to connect to the sliding one with the crazy pinion. Same the sliding one is used for two speeds, since it takes a cone to each side, and the sliding outside gears with one or another pinion, like can be appraised in the 2, in which, by means of two synchronizers, four synchronous speeds are obtained. 5 Group splitter In the 6 imagines an additional group splitter, that can give two relations of speeds. Fast range (long) and slow range (short). 6 Reducing group the 7 represents a reducing additional group. It is an additional group to the gear box that allows to duplicate its number of speeds. 7 The combinations of these relations, with the gear box, do possible to obtain a velocity range with two phases: Fast (long). Slow (short). The conductor arranges, generally, to each position of the gearshift of a fast relation and another slow one. to be combined both ranges, in the total of positions of the handle, the double of relations is obtained. The partial or total combination will depend on the conditions and circumstances of use of the vehicle. To the use of the group, the gearshift, has a preselector of fast or slow range. 8 In the 9 the different positions of the transmission gear shift imagine. 9 Converter of pair 0 In some vehicles the hydraulic clutch by a hydraulic converter of pair is replaced. This converter is similar to the clutch hydraulic, to which a reactor or stator is added to him, placed between the pump and the turbine. This stator has you praise which the liquid spurt affects, changing its trajectory to affect of more appropriate form you praise of pump and turbine that is united to the primary one of the gear box. The converter allows to reduce to the speed in a half, automatically, increasing the effort of turn to the double, and everything of progressive form, in the turbine. To the motor steering wheel the pump is united. The automatic use of hydraulic clutches, converters and changes, have like disadvantage the price of acquisition by a side and, on the other hand, the greater fuel consumption, compared with another vehicle equipped with conventional gear box. Box of speeds of automatic change With the purpose of making more comfortable and simple the handling of the automobile, being not worried to the conductor of the handling of the gearshift and the clutch and not to have to choose the march adapted to each situation, the automatic speed changes were devised, by means of which the speeds are changed without the intervention of the conductor. These changes take place based on the engine speed, of the speed of the vehicle and the position of the accelerator. The change is preceded of a hydraulic clutch or converter of pair. Although it lacks clutch pedal, yes it has gearshift, or rather selective handle of speed, that can be located in different positions. A parking position immobilizes the vehicle. One second position of deadlock allows to accelerate the motor with the stopped vehicle. One third position, that they automatically enter the first and second speed solely, own for maneuvers. One fourth position, that is the normal conduction, in that enters all the speeds forwards automatically. A fifth position is for the reverse gear. 1 Control of manual change of marches Direct control In the gear boxes of manual drive, is used a system handle of linkage and brackets, to move to the synchronizers or pinions. 2 In order to avoid that the speeds can leave and to remain fixed in the selected place is had a mechanism of retention of the bracket or the axis of the bracket, according to is, that one or this one, the one that moves. In 3 and 44 the fixation system has imagined that it avoids that the selected speed can leave the corresponding pinions. It consists of the balls and wharves that fit in recesses of the sliding bars, that they prevent that these move by single himself and its brackets. When the conductor drives the handle of the change and moves one anyone of these sliding bars, depending on the speed that it selects, the effort makes be compressed the wharf, allowing the ball the movement of the bar, that once arrival to its top presents/displays a new recess to the ball, which becomes engraved in her by the action of its wharf, thus being fixed the speed and being avoided the disengaging of the pinions. 3 In order to select the speeds correctly and to avoid that between a speed when another one is put it places a device in the change. 4 This one consists of a selective plate, so that, to happen from a speed to another one is necessary to happen through a deadlock, which makes disconnect the speed that was put. Control by cables the new control system of the change of traction by cable does not need maintenance. It is characterized, among other things, by his precise and smooth drive, his little transmission of noises and the elimination of the any movement, or vibration of the handle. 5 Power shaft the mission of the power shaft, is the one to transmit the revolving movement from the secondary one of the box of speeds to the differential, located in the motor bridge. It is used, logically, in the case of front motor and propulsion. 6 It is constituted by an extended and cylindrical piece, that go united by one of the ends to the secondary one of the gear box, and by the other to the pinion of the conical group. It is a articulated axis since it must allow to the effort and the movement of torsion with the oscillations of the suspension. One makes in steel with high coefficient of elasticity to compensate the mentioned efforts previously and for the oscillations. In each end of the power shaft universal joints are placed. The universal joints allow to the ascent and slope of the wheel by flexion of the crossbow. The back bridge describes an arc determined by the length of the crossbows from its fixed point. The power shaft moves according to a different arc, reason why its length has to modify itself, to compensate the difference. This obtains with a sliding connection that they allow to variations in the length of the power shaft and different angular positions. These connections can be: or power Shafts with sliding meeting by telescope. or Universal joints that can be: Elastic? Cardan joint? Homocinéticas.? Power shaft with sliding meeting by telescope the sliding meeting by telescope allows the length variations, by means of a fluted axis male that fits in a sleeve female. It requires of lubrication and a protective cover. Elastic Together universal joints Constituted by a floppy disk in whose faces the ends of the axis go united which they connect. These finish in three arms, and the fixation to the disc is to the staggered formation those of a part, with those of the other, by means of screws. With it, one is not only able to give flexibility to the power shaft, but to absorb his displacements longitudinal. 8 Also it can be constituted by a rubber ring (flector) resistant with orifice that takes metallic sockets and allows angular oscillations of 8º. 9 Universal joint the universal joints cardan joint are used at the moment. They allow angular oscillations and of until 25º. 0 They are formed by a crosspiece, in whose arms they go articulated the ends of a bracket in which they finish both extreme of the axis which they connect, so that the axes on which will turn the brackets are the arms of the crosspiece. In order to absorb the possible displacements longitudinal, as it were seen in the 7, the union of the axis to the universal joint is made in sliding form, by means of fluting and within as it can move slightly. If the trees, united by the cardan joint well are not mounted, the transmission of the movement is made of irregular form. In each return there are two accelerations and two decelerations. In order to avoid this irregularity, a meeting in each mounted end of the tree of a certain form is placed. If this assembly is incorrect it can be cause of important failures. These meetings go locked up in a case with consistent fat by means of the lubricator, in order that always properly they are lubricated, mainly the bearings of needles. 1 Homocinéticas meetings the speed variations that are originated in the meetings of normal type do not cause important difficulties in the power shafts of the vehicles automobiles in which the transmission angles are small, but in the case in that the front wheels in addition to directives are motor, with angular displacements of 38º, the fluctuations of speed create a serious problem. The meetings of normal type would bring with himself a hardening in the direction, as well as blunders and wearing downs of the covers whenever him vehicle carried out a turn, reason for which, in these types of vehicles the homocinéticas meetings are used at the moment to connect the front semiaxis to the driving wheels and to allow great angular variations. The automobiles of front traction take, when coming out the differential, shafts power or semiaxes (palieres), but also need a simple universal joint, to allow the movements of the suspension in this same end. 2 In the other end, corresponding to the wheels, homocinéticas meetings mount, to facilitate the movements of the direction, as well as the verticals, sent by the suspension. In the 3 a type of homocinética meeting Bed model can be seen, formed by two normal universal joints. 3 In the 4 two homocinéticas meetings imagine that use balls guided on tracks in the direction of the semiaxis. This type uses the Bendix-Weiss model. 4 In the 5 the homocinética meeting Tractán imagines, employee in heavy vehicles, specially. This meeting takes, in its central part, a sphere formed by two pieces in form indented in its central part. With the homocinéticas meetings, calls of constant speed, obtain that the exit and input axes turn at the same speed, without variations, in a very ample range of angles. 5 Conical group differential (6)? Mission the back bridge, with its group of pinion and crowns (even conical), it constitutes the final transmission and its mission is to obtain that the transmission of the movement that comes from the motor, happening through the clutch, gear box and power shaft, changes in right angle to transmit the driving force to the wheels. That is to say, which it transforms the driving force that arrives from the power shaft in longitudinal sense, into cross-sectional in palieres. Several forms of gear exist that allow to transmit the effort from an axis to another one in right angle and without appreciable loss of power. In the group pinion-it crowns of the final transmission takes place a reduction of speed of 4:1 or of 5:1 in the modern cars, so that when in the change the direct speed is put, the wheels turn to 1/4 or 1/5 of the RPM of the motor. In trucks the reduction even gets to be from 11:1, that is to say, the crown has 11 times more teeth than the attack pinion. 6 Types of gears used in the group pinion-crown In the 7 sees a cut of the back bridge and in him, the pinion of attack and the crown taken by screws or rivets to the box of satellites. The hipoide type (7) more is adapted for tourism and light trucks, since it allows to place the pinion of attack below the center of the crown and to lower therefore the power shaft to be able to lower the floor of the body, considering in addition that its operation is quiet. 7 Back bridge of double reduction (8) In heavy trucks great reductions are used and these are made in two stages: or In the entrance to the bridge. or Placing a reducing mechanism in palieres, the bucket of the wheels, after the differential. If the reducer can be annulled, each relation of the change can normal or be reduced. Of this form the number of speeds available in the truck is duplicated. 8 Differential (9) Mission If the axes of the back wheels (back propulsion), were united directly to the crown (of the group pinion-it crowns), necessarily would have to give to both the same number of returns. When taking a curve the outer wheel describes an arc greater than the interior; that is to say, they have to cross different distances but, like the returns that they give are the same ones and in the same time, unavoidably one of them will drag to the other, that it will slide on the pavement. In order to avoid it one resorts to the differential, mechanism that makes give greater number of returns automatically to the wheel that goes by the outer part of the curve, that those of the interior, fitting them and maintaining the sum of the returns constant that give both wheels in relation to the returns that took before entering the curve. When moving the in line straight vehicle, both driving wheels cross the same distance at the same speed and in the same time. 9 Operation (0) When taking a curve, when the planetarium corresponding to the wheel that goes less by the inner tour than the crown, the planetarium of the outer wheel, moved by the satellites, turns proportionally more express. This system of gears, planetariums and satellites, allows that, when taking the curve in which the whole ranges by each wheel are different, the number of motor returns of the crown is distributed proportionally to the planetariums in the same measurement that the returns of the corresponding wheels. In details a) and b), the different moments from operation of the differential imagine. In a) in straight line (V1 = V2) and b) in V1 curves = V2. V = Speed 0 Front traction (1) the driving wheels are the advantages, simultaneously that directives. The motor goes in the front part of the vehicle, forming block with the transmission, because the turn movement is transmitted directly to palieres that they take homocinéticas meetings to absorb the oscillations of the wheels. 1 Comparison of both systems In the front traction, to the being the direction of the strike in the same direction of the wheels directives, the curves can be taken at greater speed and security than with back propulsion in which the push is the same direction that the one of the longitudinal axis of the vehicle, therefore, oblique with the direction of the wheels directives, thus is dangerous to take the curves at great speed because the car could leave the road. It forces to reduce the speed in the entrance of the curve and to accelerate within her, when the angle that forms the longitudinal axis of the vehicle with the direction of the driving wheels has diminished. The stability of a car with front traction is greater than by back propulsion when suppressing itself the power shaft, the floor of the car can lower, with which the center of gravity descends. The cars with front traction lose adhesion in their driving wheels when raising hills; the weight is recharged on the back axis, very important circumstance because it is cause of which the front traction is almost prohibitive for great cars and trucks in which already of by himself it loads the greater weight on the back axis. Double propulsion (2) In trucks with back axis double, can be both propulsive. The transmission of the turn movement can be: or By two power shafts that take the movement independently to the differential of the back bridge of each axis (detail A). or By a power shaft that takes the movement to the back bridge of the first axis, and, from the crown of this one, in which it gears a second pinion of attack, the movement is sent to the back bridge of the second axis (detail B). or By a this one and power shaft that takes the movement to the back bridge it sends it by each palier to two wheels (detail C). 2 Total transmission All the back and front wheels are motor. The advantages can be made motor voluntarily of the conductor. Most of the vehicles they transmit the power to two of his wheels: the advantages or the back. When the highway becomes slippery because of snow, ice or mud, it is possible that the driving wheels do not adhere and one or the two slide. If the four wheels are motor, the tires adhere better to the sliding floor, since all the weight of the vehicle is used in the traction. The transmission to the cuatros wheels is habitual in vehicles “all land”. These vehicles work, generally, with propulsion to the back wheels when they circulate around good highways, because he is not advisable to use the transmission to the four wheels in long routes and at great speed. The additional traction to the front wheels is connected by means of a handle that at the same time selects a relation of shorter march. The 3 represent the disposition of the different elements from a truck with total transmission. When coming out of the change a box of gears is placed that allows to connect or to disconnect the front axis and to reduce the speed. 3 Controlled differential (4 and 65) the mechanism of the differential has a great disadvantage: if a driving wheel suffers a great loss of adhesion by mud, ice, snow, etc., all the movement and the driving force go away through the wheel that slides not advancing the vehicle or not initiating the march. In order to avoid this disadvantage, some vehicles, they take a mechanism that blocks the differential by means of the drive of a switch that allows the action of the sliding one and collarín. or a witness in the board of instruments indicates if collarín has blocked the joint differential. or he only must be used in case of true necessity. or In normal circulation, to take annulled the differential, he could skid in the curves. 4 5 Autoblocante differential Existen autoblocantes mechanisms of operation automatic, that allow slight differences of turn between wheels and that annul the differential if the speed difference increases considerably in one more a wheel than in the other. These differentials do not allow the excessive turn of a wheel with respect to the other. For example, if we were in a zone of mud and a wheel is buried until being blocked, the other would turn the double and also it would be buried. These differentials annul, at certain moments, to the action of the differential (they force the two wheels to practically turn to the same revolutions), allowing that the wheel that is not in the mud takes hold and moves the vehicle. It is a very interesting element for the conduction security (conduction in ice or slippery lands). Nonskid system ASR (6) the mission of system ASR is to avoid situations critics due to the slip of the driving wheels, during the starting and the march of the vehicle. During its operation the slip of the driving wheels is regulated, preventing that these reach an excessive speed at the moment of starting, the curves and conditions of loss of adhesion in the road. One is able to improve the traction and the guidance in lateral sense of the wheels. It is possible to be considered as a complement of the system antiblockade of brake ABS. Operation the ASR compares the different speeds from the wheels to each other. If a driving wheel tends to race and increases of slip, gives to the opportune orders for its braking, allowing the increase of traction in the other wheel of greater adhesion with the road. If all the wheels of the motor axis tend to race, the engine power independently of the position of the accelerator obtaining of this form is reduced automatically, that the wheels can continue transmitting the tractive forces the road. The regulation of the motor also can be when it is used like brake-motor. 6 System of raiseable axis of drag (7) the raiseable axis is not motor because it does not receive movement of the transmission. Without load is getting up, being reduced the wearing down of the tires and the consumption. With load it descends automatically helping to support part of this load. If the conditions are of minimum adhesion, facilitates the starting, their possible rise during just a short time, taking place a motor transference of load in the axis or axes. In the figure different dispositions from the raiseable axis imagine. 7 Types of back bridges. Palieres (8) palieres or semiaxes transmits the movement from the differential to the wheels. One of its ends goes united by means of striae to the corresponding planetarium of which it takes control shared in common, the other end fits in the bucket of the wheel, also shared in common, to transmit its turn to him. Palieres goes within prolongations of the case of the differential, calls “trompetas”, on which the suspension mounts. 8 Types of assembly of palier Semiflotante (detail A) the bucket of the wheel leans on palier that it supports to the effort of turn or torsion and the weight of the vehicle, since the trompeta does not arrive at the bucket. In order to disassemble palier it is precise to extract the wheel. The wheels support just like palier, the weight of the vehicle. This system is used at the moment in the tourism. The end of the semiaxis corresponding to the planetarium, is frees from the effort, working without as much load. Semiaxes three floating quarters (detail B) to extract palier are necessary to clear the bucket of the wheel; case that it was broken, the wheel is not assured in its turn. The wheels support the three fourth parts of the weight of the vehicle, and palier one third part. Floating semiaxis (detail C). The wheels can turn perfectly without palier when doing it on the trompeta. System very used in trucks. The wheels support to all the weight of the vehicle and palier nothing. Rigid semiaxis is not applied at the moment. Maintenance? Clutch is had to come to its setting (9), acting in the nut to leave the route free when we observe that it loses effectiveness. If it is of hydraulic drive it will watch the drive liquid. The clutch disc will be replaced when he is not able to transmit movement. In a hydraulic automatic clutch the oil will be replaced following the advice of the manufacturer. 9 Gear box At the moment does not have more maintenance than the change of the valvulina after the period of running to clean to the flash case or impurities and later to verify the level? Differential Substitution of the oil of the case following the data of the manufacturer during the period of running and later the verification of the level.
The address is the set of mechanisms that are responsible for guiding the wheels guidelines and adapting the layout of the track on which it is moving, as well as to perform various maneuvers that his leadership requires.
The suspension has as its mission the deficiencies of the land does not reach the vehicle body or do so as diminished as possible. To this end, between the wheels and chassis, it puts an elastic binding elastic that cause deformation of the vehicle with the weight and inertia of the same or lowered to rise as a result of irregularities in the pavement…
The mission of the braking system is to create a force regulated to reduce speed or to stop a moving vehicle, and to have it parked…
The wheel is an automobile that is in direct contact with the pavement.
Its mission, in addition to bear the weight of the car, is to transmit power from the transmission in order to move the vehicle, and provide direction and adherence in moments of acceleration and deceleration.
TROUBLESHOOTING AND MAINTENANCE OF ELECTRICAL AND MECHANICAL CAR
Triangle breakdowns
Periodic reviews by the driver
1. Clean the vehicle.
2. Change oil filter.
3. Level of engine oil. Change filter.
4. Check cooling sleeves.
5. Level change and coolant.
6. Voltage strap generator, water pump.
7. Battery. Level electrólito.Conexiones
8. Power. Checking spark plugs and cables.
9. Deposit of washer systems.
10. Deposit of lavalunetas.
11. Check connections generator.
12. Check connections engine starts.
13. Level hydraulic clutch.
14. Level of the power steering fluid.
15. Jets of lavafaros.
16. Adjusting the suppliers of washer systems.
17. Checking the status of the brushes of wipers.
18. Check brake pedal travel. Pills.
19. Check trail parking brake.
20. Check tour clutch.
21. Level of change.
22. Level of the brake fluid reservoir.
23. Pressure tires.
24. Grease.
25. Grease hinged door locks.
26. Conservation tools and equipment.
27. Documentation of the vehicle.
The revisions indicated in the service book, were virtually referenced in this relationship while others relate to be carried out in workshops recommended as trademarks.
Revisions levels, fluids and other elements of the vehicle
Differences between the injection and carburisation
In gasoline engines, the mixture is prepared using a carburetor or injection equipment. So far, the carburetor was the most common mixture preparation, mechanical.
dvantages of the injection
Consumer reduced
With the use of carburetors, intake manifolds in the mixtures are produced uneven air / gasoline for each cylinder. The need to form a mixture that even enough to feed cylinder compels most disadvantaged, in general, a quantity of fuel dispensed too high.