Cars and Tuning

Definition and classification of motors
By motor all machine is understood that transforms into work any type of energy.
The motor of the used automobile today can say that it transforms the stored chemical energy into a fuel, or the stored electrical energy, in storage cells, mechanical energy.

The types of generally used motors in the automobile, are motor thermal of internal combustion:
or Of explosion (they use gasoline).
or Of combustion or diesel engine (they use diesel oil).
Also the electrical motor exists, that takes advantage of the stored electrical energy in a storage battery.
Motors of internal combustion
They can as well be classified, according to the form to be made the combustion in:
Motors of ignition caused by a spark
It is characterized because the combustion is made with the intervention of spark. Explosion motors are denominated.
Compression ingnition engines
It is characterized because the combustion is made by pre-ignition due to the high temperatures reached about effect of the pressure. Motors of combustion or diesel engine are denominated.
Generally, the motors used in the light vehicles are of explosion and combustion. The used ones in heavy vehicles are of combustion, due to their smaller consumption and greater duration.
They can be of two types: alternative and rotating. The most used they are the alternative ones and except the rotary engines (Wankel).
Elements of which the motor consists
The elements of which the motor consists are common to both types that exist: of explosion and combustion. At the moment small differences exist, when obtaining itself great resistance in the materials and little weight.
These elements can be divided in two great groups:
or Fixed.
or Moving bodies.
Fixed elements by importance order
They are those that compose the frame and the external structure of the motor and whose mission is to lodge, to hold and to cover the elements of the set. These are: the block of cylinders, butt, case and cover of balance beams.
Block of cylinders
It is the main element of the motor. In him two parts can be distinguished: cilindrosy the large stone bench or superior case.
The cylinders
They are cylindrical oquedades where an alternative linear movement between its two extreme positions will move to the piston making (P.M.S. top dead center and P.M.I. bottom dead center).
The cylinders can comprise of the same block or to be independent of these. In addition the block is designed stops:
or To connect the refrigeration pump.
or the necessary conduits for the circulation of the refrigeration and lubricate.
or the supports of the crank and the camshaft.
or the connections of the ignition distributor, oil filter and gasoline pump.
The large stone bench or superior case,

It is the inferior part of the block, destined to contain and to hold the crank.
Three types of blocks exist according to the assembly and subjection of the cylinders. These are:
or integral Block.
The form a single piece, with cameras for the cooling liquid. The cylinders are obtained in gross, later happening to be made a mechanization to obtain perfect finishing. With this system, the fused initial cylinder (fused iron) is of a measurement smaller than the final cylinder.
In the case of an excessive wearing down in the walls of a cylinder, it is necessary to rectify all to a superior measurement and to replace pistons, bolts and segments by others of greater diameter to again obtain to a perfect adjustment between piston and cylinder.

or Block of dry shirts.
In this type of block, the cylinders go mechanized just as in the previous case, but in its interior they lodge, to pressure, other cylinders (special steel), with the finest walls, denominated shirts, that in this case are not in contact with the enemy with the liquid of the refrigeration system, making difficult partly the refrigeration of the cylinder.
Its main advantage is that when taking place the wearing down of these shirts new ones of the same measurement can be placed other that the original ones, with which the original diameter of the pistons is conserved.

or Block of humid shirts
The block is totally hollow and the shirts, are not introduced to pressure, but that leans on the block forming the water boxes, being in direct bonding the shirts with the water. This block is the one that better refrigeration offers, having like disadvantage the difficulty of remaining fit in its assembly the shirts.
The watertightness or fits makes sure with special a synthetic rubber ring or receives in the inferior part, and another one in the superior part. Its assembly does not present/display difficulty. The use of shirts causes that light alloys in the manufacture of the blocks can be used, with which the diminution of weight is very considerable.

Butt

It is the piece that goes mounted in the superior part of the block, that for of cover and has been closing to the cylinders, forming the combustion chamber.
Inside the butt there are oquedades so that the refrigeration liquid circulates, that are communicated and faced the water boxes of the block. 000
In the inferior part of the butt, they take hollows that form the combustion chambers. Within these, the drills to lodge the valves and their seats, the spark plug or the injector, in case of an injection motor.
It takes to orifices for the guides of valves and their fixation with the block through screws or asparagus. Also it has conduits (OF) for the entrance and exit of gases, the assembly of the collectors (admission and escapes) and others for the oil passage.
According to the type of in question motor, butts for motors of four times or those of two times exist.
The material used for its manufacture is light the aluminum smelting or alloy. These last ones are used.
They are classified in:

Butt for motor with lateral valves.
Butt for motor with valves in head and lateral camshaft.
Butt for motor with valves and camshafts in head.
Butt for motors of two times.
or Butt for motor with lateral valves (fig.7)
The block takes the orifices where the admission valves lodge and escapes. The butt constitutes the cover of the cylinders, the compression chamber and the orifices for the spark plugs. She is cheap and of easy construction. At the present time it is in disuse.

or Butt for motor with valves in head and lateral camshaft.
It takes the refrigeration chambers, the orifices of admission and escapes, orifices for the spark plugs, as well as the practiced ones for the system of drive of the valves (balance beams and pushers), and the combustion chamber.

or Butt for motors with valves and camshafts in head
To the orifices mentioned in the previous type, it is necessary to add the supports of the camshaft with which its complica manufacture and increases in price remarkably. At the present time it is the used type more because the control of the distribution simplifies to much when grouping itself all the organs in a space very reduced and to eliminate the pushers (rods).

or Butt for motors of two times
The butts for motors of two times do not take distribution elements still more, being simple if the refrigeration is by air.

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Meeting of butt
The block closes on the other hand superior with the BUTT, forming a camera where the cycle of work will be developed. Between both surfaces an air seal is placed denominated TOGETHER OF BUTT. Its mission is to maintain the watertightness between the surfaces of the block and the butt and to avoid that the gases that come from the combustion enter the refrigeration chambers. In addition, in case of deterioration of the meeting, the refrigeration liquid could pass to the inferior case and the oil to the conductions of refrigeration, appearing oil in the expansion glass. One makes of a grafitado and adaptable material, that is resistant to the high temperatures and the deformations.
The butt meeting takes drilled all the orifices that take to the butt and the block in their faces of contact.

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Inferior case
Its mission is the one to protect to the inferior mechanical organs. It serves as deposit to lodge the oil of the motor once it has crossed all the circuit of lubrication and of which, through the lubrication pump that goes lodged in its interior, becomes to gather to begin its route again.
In its interior they are placed one or several partitions to avoid the abrupt variations of level and the curing of the oil (one thickens by its movement). Sometimes it has a series of fins in the outer surface to increase the zone of refrigeration of the oil. In the lowest point is the drained cork of.

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Cover of balance beams
Its mission is the one to protect the organs of the distribution: taqués, camshaft and balance beam (mechanisms of opening of the valves), and avoids as well that the oil leaves that is used for its lubrication. Also it takes the oil filling cork in the superior part.
It goes fixed to the butt by means of a meeting that avoids possible oil flights.
One makes of inserted plate.

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Movable elements
They are the ones in charge to transform the chemical energy of the fuel into mechanical energy. These elements are:

The piston.
The connecting rods.
The crank.
Piston
It is the movable element that moves in the interior of the cylinder. It directly receives the force of expansion of gases during the combustion, that forces to move to him with an alternative linear movement between its two extreme positions (PMS - PMI).
Missions of the piston
or To transmit to the connecting rod the force produced in the interior of the cylinder during the expansion of gases.
or To avoid gas flights as well as the passage from oil to the combustion chamber.
or To lead part of the heat produced in the combustion and to transmit it to the walls of the cylinder to evacuate it to the refrigeration system.
Description of the piston
It has form of inverted glass and two parts can be distinguished: head and skirt. The head takes to grooves or throats where the segments will lodge. The piston slightly has an inferior diameter to the one of the cylinder. The head can be flat or with special forms to obtain the air turbulence partly, as it happens in the diesel engines. The skirt takes a pasante drill, whose length corresponds to the diameter of the piston. In this drill the bolt is introduced, that will serve to connect the piston and the connecting rod.

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Characteristics of the piston
Due to the efforts that it has to support a piston (lateral frictions and temperatures), the materials used in their construction must reunite the following characteristics:
or robust Structure, mainly in the zones of greater effort, the head and the bolt.
or To have the smaller weight possible and to be perfectly balances, to avoid I ring the bell, lateral golpeteos and the efforts of inertia.
or Resistant to the wearing down, the high temperatures and the oxidating or corrosive agents.
or To have great thermal conductibilidad.
The pistons make with light alloys. They can be of iron smelting, although at the present time little they are used, because they present/display the problem of a greater expansion with respect to the walls of the cylinder and their greater weight, than affects the inertia efforts.
If these pistons mount fit, when warming up itself the walls and the motor would be bound tightly to griparía; but if they mount with much comfort, they would shake one’s head in cold. In order to avoid this, the pistons with the skirt of greater diameter are constructed than the head and two grooves practice in the skirt, a horizontal and another vertical, in some types of pistons.
The horizontal groove limits the heat transmission of the head the skirt. The vertical, does that when dilating the skirt, this one is not close with the cylinder.
Another system to make the piston with the skirt slightly made oval and the perpendicular greater diameter to the axis of the bolt, that is where the greater effort takes place. Of this form when dilating the pitching of the piston adjusts perfectly the same in all the surface of the cylinder avoiding.

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Segments
They are an elastic steel ring located in the grooves of the head of the piston. It has a cut to facilitate his assembly and a separation for his expansion. The segments have like mission:
or To make the camera watertight of understanding.
or To transmit the heat of the head of the piston to the wall of the cylinder.
or To avoid the passage from oil to the combustion chamber.
If the segments did not make a perfect watertightness, due to an excessive wearing down, it would be possible to be produced:
or Power loss.
or excessive oil Consumption.
or fine coal Formation in the camera.
or Provocation of pre-ignition, due to the worse refrigeration of the camera by the fine coal creation.

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According to the function that makes, the segments are classified in:

Compression rings.
Segments of lubrication.
or Compression rings. Located in the high part of the head of the piston, they must like mission assure the watertightness in the cylinder. By their position the temperatures and pressures are affected by. First from them (closest at the top of the piston), it directly receives the effects of the explosion. It is known him with the name of fire segment. The rest are put under less severe conditions of work, are the obturator rings.
The total of compression rings varies from 2 to 3, depending its number of the compression ratio on the motor.

or Segments of lubrication. Located underneath those of compression. It has the mission to gather, during the reduction of the piston, the excess of oil deposited in the wall of the cylinder. Through the drills, that the lubrication segment has so much as its lodging, the oil is sent towards the interior of the piston, to lubricate the bolt; this oil returns to the inferior case by gravity. This segment also is known like “rascador” or of cleaning and always they will leave a small oil film, between the piston and the cylinder.

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Bolt
It is the element that serves as union between the piston and the connecting rod. Its robust structure allows to support the efforts him which the piston is put under. It has cylindrical and drained form inner. They make with treated and rectified steel.

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Connecting rod
It is the element that serves as union between the piston and the crank. Its mission is to transform the linear movement of the piston into rotating movement. It is put under concerted efforts, such as traction, flexion and compression. In her three parts can be distinguished: foot, body and head.

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Foot
It is the narrowest part of the connecting rod. It is united to the piston through the bolt. Between both pieces a socket is placed generally antifriction. The foot has an oscillating movement.
Body
It is the longest part of the connecting rod, located between the foot and the head. It is the zone submissive the efforts previously mentioned. Sometimes it has a pasante drill in all his length to assure the lubrication the bolt, and its section is in form of or double.
Head
It is the widest part and the elbow or muñequilla of the crank is united to. Between both pieces two semibearings are put in antifriction. In order to facilitate the assembly in the elbows of the crank, the head is divided in two parts. A called part semihead, that goes directly united to the connecting rod, and the other call small hat, being the detachable part that will be united to the semihead through screws or to per to us.
Golpeteo in the connecting rods (mincemeat)
It is a metallic noise. It is looked like which obtains when moving energetically a crystal bottle with pellets.
It can be due to:
or That hurries the motor too much (high number of revolutions).
or Excess of advance to the ignition.
or Detonation.
or Pre-ignition.
Fused connecting rod
It must to a lack of lubrication in the head of connecting rod or supports of the crank.
It appears a metallic and alarming golpeteo, due to the fusion of the metal antifriction of the semiscasquillos.
Crank
Motor tree is an axis also denominated. Its mission is the one to turn the linear movement of the piston, in revolving movement, to later transmit it to the wheels through the transmission system. It is of special steel and with the polished surfaces of friction.

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Supports
They are the parts that serve as subjection to the crank in the large stone bench. These will be aligned with respect to the spin axis and its number will be equal to the number of cylinders of the motor plus one (motor in line). A motor in four cylinders in line has generally a crank with five supports and they lodge in the large stone bench.
Elbows or muñequilllas
Located eccentrically with respect to the axis of the crank. They are the places on which the connecting rod heads mount. In the motors in line the number of elbows will be equal to the number of cylinders. In the motors in “V” he will be equal to half of the number of cylinders, shortening the length of the motor; in each elbow two connecting rods mount.
Bearings or sockets antifriction
The heads of connecting rod and the elbows are located between and between the supports and the large stone bench. They are formed by a material antifriction to avoid the wearing down by friction in the turn and joint places.

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Counterbalances (2 and 23)
They are perfectly distributed masses in relation to the rotation axis, so that the crank always is left to balance avoiding possible vibrations of the motor.
For the lubrication it takes canalizations that all the length of the crank crosses, with starting points in elbows and supports. The crank, in addition, is the one in charge, in its previous end, to drive a fundamental series of elements and systems:
or the camshaft of the distribution system.
or the water pump of the refrigeration system.
or the pump of the attended direction, if it were installed.
or the depressor, if it were installed.
or the alternator.
or the conditioned air, if it were installed.
or the compressor, if it were installed.
or the steering wheel of inertia in its later end.
Steering wheel of inertia
The mission of the steering wheel is the one to regularize the operation of the motor, storing the energy obtained during the time of combustion and yielding this energy in the passive times, maintaining therefore the regularity in the turn.
In a motor of four times, a time that produces work (explosion) and three resistant times, with which only exists the movement to transmit would not be uniform or regular.
Its form is circular, heavy, together with by means of screws the crank and located in an end of the crank. On the other hand outer, an dentated crown mounts so that it gears the pinion of the starter engine. By a side it is united to the crank and by the other, the clutch will be reconciled.
Whichever greater number of cylinders has the motor, minor will be the size of the steering wheel, since the explosions less will be spaced and the torsion and rotation of the crank will be more perfect.
The steering wheel usually has marks or references that are used for the setting as the distribution and the ignition.

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Dámper or antivibrator
Located in the opposed end to the steering wheel is antivibrating dámper or, that is in charge to absorb the vibrations and oscillations of the crank. Its effectiveness note, mainly, when one is a motor with high number of cylinders, or with an excessively long crank.

Types of motor according to the number and the disposition of the cylinders
The motor can lodge in the front part of the vehicle or in the back part; it can go cross-sectionally placed longitudinal or to the axis of the vehicle.
The relative disposition of the cylinders, can be:
or Motor of cylinders in line.
or Motor of cylinders in “V”.
or Motor of opposed horizontal cylinders (to boxer).
Motors of cylinders in line
The cylinders go placed after the others. The number of used cylinders more is those of 4.6 and 8 cylinders.
Those of four cylinders are used in the series vehicles.

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Motors of cylinders in “V”
The cylinders form two blocks placed in “V”, sharing the same crank. The number of elbows will be equal to half of the cylinders that has the motor. In each one of the elbows of the crank two connecting rods articulate. They are used to shorten the length of the motors that have an elevated number of cylinders.

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Opposed cylinder engines or “boxer”
The cylinders are placed in horizontal direction in opposite blocks and are noisy, by being cooled by air generally. With this assembly the height of the motor at the cost of using more lateral space is reduced.

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STARTUP CMD of a motor
It is the order in that jumps the spark in the spark plugs of each cylinder, or the injection in the diesel engines.
The STARTUP CMD in the motors settles down so that the efforts that the crank in each explosion receives distribute the most distanced possible and the followed explosions do not take place, one near the other; obtaining this way one it marches smoother and regular the motor.
The more habitual STARTUP CMD, according to the number of cylinders, imagines in the following picture.
Motors in line
4 Cylinders 6 cylinders
STARTUP CMD
Or COMBUSTION
1 - 3 - 4 - 2
STARTUP CMD
Or COMBUSTION
1 - 5 - 3 - 6 - 2 - 4

or:
1 - 4 - 2 - 6 - 3 - 5

Motors in “V”
6 cylinders
STARTUP CMD
Or COMBUSTION
1 - 3 - 6 - 5 - 4 - 2

8 cylinders

STARTUP CMD
Or COMBUSTION
1 - 5 - 4 - 8 - 6 - 3 - 7 2

Opposed cylinder engines or “boxer”
4 cylinders
STARTUP CMD
Or COMBUSTION
1 - 4 - 3 - 2

Measurements and characteristics of a motor
Race
It is the existing distance between the P.M.S. and the P.M.I., in millimeters.

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Caliber or diameter
It is the inner diameter of the cylinder. This data is expressed in millimeters.

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Piston displacement
It is the existing volume between the P.M.S. and the P.M.I.
This data (rolled or volume) is expressed in cubical centimeters or liters.
V = (pi x D2 /4) wagon x
This is the unitary piston displacement.
The collected data corresponds to the volume of a cylinder. Multiplying this volume by the total of cylinders, the piston displacement of the motor is obtained.
Compression ratio
It is the existing relation between the volume which they occupy gases before being compressed (volume of the cylinder plus the volume of the compression chamber) and the volume that once occupy compressed gases (volume of the compression chamber).
Rc = (V + vc)/vc
The compression ratio in the explosion motors usually is between 7-11 to 1, and in the diesel engine from 18-24 to approximately 1, being the double in some diesel engines with respect to those of explosion.
Power
It is the work that produces a motor in the time unit. The power is moderate in horsepowers (C.V) or in kilowatts and this it depends on:
or the piston displacement.
or the compression ratio.
or the number of revolutions of the motor, until a limit.
or the filling of the cylinders or volumetric relation.
Although all these factors influence or determine the power of a motor, the one that influences more of them is the number of revolutions, until reaching the revolutions of Maxima power.
Motor pair
It is the force that are applied in the connecting rod and this one on the elbow of the crank. The motor pair increases; until reaching its maximum value to half of the revolutions, approximately that gives to the Maxima power. From this point, if the revolutions continue increasing, the motor pair would diminish to diminish the filling of the cylinders.
The filling degree of the cylinders varies according to the number of revolutions of the motor. Thus the filling of cylinders begins to diminish when half of the maximum revolutions of the motor is surpassed, due to just a short time of opening of the valves. The best filling of cylinders is obtained to half of the revolutions approximately that gives to the Maxima power, obtaining itself the maximum motor pair.
In the 0 one imagines the curve of power and the one of the motor pair based on the RPM.

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Relation race-caliber
According to the existing relation between the race and the caliber, the motors can be:
or square Motors: the race and the caliber are equal.
or extended Motors: the race is greater than the caliber.
or supersquare Motors or “chatos”: the race is minor who the caliber.
Volumetric relation
It is the relation between the volume of filling of the cylinder in a while determined (real volume of gases that has entered the cylinder in the time of admission) V1 and total the theoretical volume when the piston is in the P.M.I. (V2.).
Rv = V1/V2
It are expressed in percentage.