1. Introduction to the car
Cars can be classified in terms of their purpose into three groups:
Group I: involving all the cars allocated to passenger transport, including buses ..
Group II: Included in vans and lorries, which had processed according to the uses of.
Group C: and enter the private vehicles, with vehicles such as cranes, which are used widely in the fields of industry, construction, and construction.
Despite the multiplicity of purposes for which they are used cars, these cars all working theory of one.
And the appropriate unit of power generation in the car is the internal combustion engine which feeds liquid fuel (Abannzi or diesel oil), Famayor the necessary capacity of the engine, move the movement of the engine, by groups of transmission (clutch, gearbox, Cardan shaft, krone, the management group axes) to the wheels Director - either from the front wheels, or to the rear wheels.
The structure of the car (chassis) (the metal frame, axles, and a suspension, wheels, and a command and control, brakes, exhaust and a,).
2. Introduction to How Engine:
When the combustion of fuel inside the engine turns stored chemical energy of fuel directly into kinetic energy. In the process of combustion gases, which consists in the expansion to take in every direction, causing the emergence of high pressure. The advantage of this high pressure in mechanically moving parts and various components of the engine.
The following figure shows the main components of gasoline engine (four-stroke):
Fed (Alcarburatir), in all gasoline engines, and then pulls (sucks) this mixture to the cylinders - a result of the pistons move to the bottom - where it burns inside by candles Sparks .
Where all the sliding piston (Beeston) inside the cylinder gases as a result of the payment period has, therefore, is Fadguet on the crankshaft (Karnak), quoting the movement through the connecting rod . And thus become the movement of the reciprocating piston to rotational movement of the crankshaft.
And provide the pistons rings to increase the sealing between the piston and the cylinder walls, and to prevent sticking to each other.
Relate to the short end of the connecting rod Ebas by benz piston position to the circular motion as well.
And installing flywheel in the back of the crankshaft, which is to regulate engine speed and safety, as it is equipped with serrated frame for the small clutch gear (pinion) of Bembdi movement . The group called on the piston and piston-Benz and the connecting rod and crankshaft and flywheel, the name of the crankshaft.
And is mediated by control valves in the fuel mixture and the entry of air into the cylinder and the burned gases out of them, and move through the valve camshaft usually found in a box attached. And the valves and camshaft and a means of managing what is known as the control group in the engine.
And closes the bottom of the tray attached basin oil, who works at the same time to retain the oil needed for lubrication. This is related to the basin mailbox attached a phone arbitrator ensure that no leakage of oil from the surface of contact.
The generator , is found outside the body of the engine and adding to the movement. When the engine spins the generator is working his speed enough to supply current, ignition, and feed the rest of mainstream consumers, and charge the battery Alakhtzanah.
The starter for phrase Muthur small electric highlights of it - when you run it - a small gear loves framework dentate compound Balhaddafah and managed by, around and thus the whole group crankshaft.
Is called the top position of the piston in the cylinder top dead point name, while the lowest position it is known as the lower dead point, the distance traveled between these two positions is the piston stroke . Is called the size jokes in this half as piston displacement .
And half is the movement of the plunger once Almittin points from one point to the other dead. The compressive into space is trapped between the piston is at top dead point and the top of the cylinder.
In the compressive into compressed air and fuel mixture when the piston moves upward, then electrical spark ignites.
And half in the four-engine (The Quartet-stroke cycle) is the distance traveled between the dead point, the upper and the lower dead point .
In each half spins the crankshaft by half a lap. And cut in four-stroke cycle complete the following:
Run out (suction):
Withdraw the plunger with him - at his move to the bottom - a mixture of fuel and air through the intake valve open. While the exhaust valve is closed, and closes the intake valve as soon as the piston to the lower dead point, and thus ends the first half. In this case, the crankshaft has completed a half turn.
Compressive stroke:
Compressed air and fuel mixture when the piston moves to the top to reach the upper dead point, while the valves closed, and then the crankshaft has completed a full lap.
Exhaust stroke:
Piston moves - after the completion of his work - to the top, top dead point, the direction of, pushing in front of the burned gases flushed out of the cylinder through the exhaust valve open.
Once access to the piston top dead point, the exhaust valve closes, and opens at the same time the intake valve, and in this case, the crankshaft has completed a two full laps.
To achieve the best possible use of fuel, and to obtain the best performance, should not open or close valves, or a process or the ignition when the piston in any of the points Almittin, top and bottom. To ensure good performance of the engine - even high speeds - should, in a way that the clouds will be partially open intake valve before the piston begins to move down.
It is necessary to be done to ensure the cylinder to fill the entire mixture of new objects to the way without any barriers or bottlenecks - even at maximum speed of the piston.
The access to the good performance of the engine at high speeds, you need the largest shipment of the mixture in the cylinder, and therefore remains the intake valve open for a few moments after the arrival of the piston to the point of dead lower, until at the beginning of the movement of the piston to the top, to ensure filling the cylinder the maximum charge possible of a mixture of fuel and air, which tends always to the highest result of kinetic energy.
Ideals and occurs at the end of the exhaust stroke, the exhaust valve opens partially before the end of the power stroke, ie before the arrival of the piston to the lower dead point, to allow the gases which are still under pressure, speed and freedom to escape from the exhaust. As a result, the burning gases push the piston at the lowest pressure of anti-(which is missing in capacity).
To get rid of the gases remaining after the completion of the exhaust stroke the exhaust valve remains open after the piston position to leave the upper dead point, ie at the same time in which the intake valve is open.
Thus clearing the vacuum has the lowest possible combustion in the fuel mixture and prepared for the new air combustion.
Engine components:
. Group crankshaft
Group consists mainly of the crankshaft:
Works crankshaft to convert reciprocating motion of the piston - up and down - to spin.
Flywheel and placed on the back of the crankshaft, and purpose of the budget shocks resulting from the ongoing repercussions of the movement of pistons, allowing for the engine safety and regularity of rotation.
In addition, she works to overcome the dead points of piston and ring riding the dentate used to interleave with the small gear (pinion) of Bembdi movement (marching).
Based on the end of the connecting rod big on the axis of the facility, while related to small end (head Pitman) Bbenz piston
And the end of the connecting rod big is divided into two parts, connected to each other Bmsmaran, so can be installed and linked to on the alloy loaded Bust (chair loading) located on the axis of the attachment.
When the reforms should be made special care to adjust the alignment so that the connecting rods pistons Bnoz axes parallel to the axes of fully attached, otherwise the pistons slid in Ostwantha awry, leading to severe corrosion and gluing them .
The holidays can be aware of this issue clearly when the engine sounds great.
And used pistons made of light metals widely in the field of automotive engineering. Featuring pistons good performance in high temperatures.
It consists of the upper part of the piston head and the piston rings (piston rings), while the lower part of it consists of trunk piston Oppe Abtan, Ebas and installed in the usual three rings, the purpose of maintaining the pressure of the gases generated by combustion.
After installation of these episodes in the cylinder should make sure that the face of each ring comes into contact with the wall of his disc regularly and tighten, and attention should be strictly couples rings piston Bmjariha and that it is straighter and one in the direction the hub so as not to allow leakage of air and fuel mixture directly by the trunk piston.
When installing the piston rings into account, in particular to prevent any change in form the outside so as not to affect the quality of contact between them, so it is recommended to use pliers to install them.
The piston rings are installed in place with nails, fearing to stretch joints and thaw holes when it passed the cylinder, causing considerable damage. When installing the piston rings should be avoided bumped, or roads or heavily earmarked.
Used as well (in the Quartet-stroke engines) to organize workshops (clearance) of oil. They are similar to piston rings, but Otakn little of it, as well as the presence of annular streams of animate or Mthagbat holes (slots)-mediated ring sliding surfaces.
And lead to the oil discharge holes in the trunk piston. As a result, return excess oil from the piston to the cylinder walls from the inside without prejudice to the thin layer of oil for lubrication.
The purpose of the piston-Benz transmission of the piston to the connecting rod (bel). The piston is connected to arm connection either install micro-Benz eventually connect to the arm (head of Pitman) and rotation within Abtin. Babtin or installing and running around the small end.
. Cylinder head and cylinder (cylinder Osh)
Make cylinder head and cylinder (cylinder Osh), either of iron or gray cast iron castings of light metals. Usually there is room with a compressive cylinder to facilitate the operation of the so-active surfaces of the cylinder.
Since the effective surfaces of the cylinder exposed to erosion in the job as a result of lateral compression pistons, so it should be re-turning cylinder block from the inside when a general reform - that is the degree of corrosion expansion by the incident.
And can generally be re-maps the disc and three times its weight from the inside only, due to the cylinder wall thickness decreased after each time. To avoid replacing the cylinder block after this three times pressed drum pads serves as the original records completely.
Has taken modern designs installed pads cylinders from the start, and may be the pads dry, surrounded by a casing (shirt) of the gray cast iron or light metal and touching along the perimeter of kidney, or it may be wet tight Rabatha from the top and bottom, while the surrounding cooling water to their region of Central directly.
Requires the collection of the engine into account the full cleaning, the metal working Aljmamat (Reich) or dust on the speed of destruction of the wall of the cylinder or piston.
It should be the quality of care as well as the installation of gaskets (gaskets), may lead gaskets prominent in the combustion space to the formation of carbon deposits of oil, thus increasing friction and erosion of the cylinder prematurely.
And leads to the proper operation of the engine to reduce the erosion of cylinders to a minimum, and it should connect to the knowledge of how to run and the correct settings for meaningful generally, as well as special care using the most appropriate types of oils and fuel.
During the period of softening of the engine should not be loaded Maidh stresses. In addition, the cooling has a significant impact on engine wear. In order to avoid overheating of the engine, it should care Palmha and not allowing the formation of deposits it.
And when you leave the car in the garage for long periods should be filled with oil combustion spreads so as not to rust cylinder.
And be brutal , made of asbestos with copper or asbestos with iron (tin), between the surface of the block cylinders Alcilkh accurately and between the head of cylinder (Osh cylinder) to tighten linked together, and to prevent leakage of any slot of the holes - such as the openings of cooling water slots and screws Rabat - and spreads compressive isolate from each other.
And after replacing the wild (Joan) new ones are corrupted, and after installation of the cylinder head (Osh cylinder) in the position carefully, should tighten the strap pins twice or three times when the car cut off a distance of 200 km to avoid leakage of cooling water from the mattress of the narrower parts.
And leads continue to use the gasket damaged to enter the gas burned in the cylinders nearby, instead of entering air and fuel mixture only - formed in the fed - to one of the cylinders in during the run the clouds, leading to the exact proportion of the mix, and therefore the effect to a large extent on the work of life of the engine and use. Furthermore, compressive then unable to reach the values set for it.
The situation becomes even worse when the damage the gasket to leak and allow the cooling cycle, where you can cooling water from entering the spaces in the cylinder and cause a serious damage or destruction of each engine.
In addition, the low pressure air and fuel mixture due to a damaged mattress in places during the compression stroke. It can detect the emergence of this holiday bubbles in the water Palmha filled to an end when the engine running at low speed
It must however not be confused with the emergence of bubbles in the cooling water in this case and the appearance in the case of cooling air.
When the installation gasket new should take into account with the emergence of any part thereof or Andgath inside spreads combustion or paths of cooling water as a result of tightening the ligament, it may result in the emergence of any part of the gasket to be deposits of oil, carbon cause an ignition advanced, and thus the emergence of pop (applause), known engine .
The parts that stand out from the gasket in the cooling paths is working to narrow the lanes and strangled, was severely affecting engine cooling.
It should be noted that all the designs of mattresses are not the same and arrange Forced lubrication holes on one side only, especially in women with valve engines the upper (vertical). And so does not object gaskets for these openings Vtaouk force the oil, should be checked carefully before each brutal installed.
. The control group in the engine:
Include a control group in the engine all the parts that control the stroke cycle, the timing of the movement and how to control the valves in the nozzles.
The group consists of the timing of the movement of the valves engine four-stroke ever valves vertical (in the case of a valve with a motor) of the camshaft, and cranes , valves Baayatea tablets Springs (plates) and cones valves, and arms push the valves, and arms vacillating.
If the camshaft above the valves do not need all of levers or arms push the valves form.
To facilitate the process of grinding and nursery open incision in force along the top of the valve in case of ball-valve format, or in the open part of the trypanosome milling the road in case of LED flat shape.
The surface consists of the Interim - connecting the valve disk and the leg - the curve of the connection, for a gradual transition section, and avoid the refraction of the valve.
The valve is opened by lifting his leg and the arm of the crane arm and vacillating payment that by moving the existing cams cam shaft, and the lock are Yai by the valve.
The rate fill cylinders, and thus the performance of the engine, the design of the valve mechanisms, and how they work, and for an appropriate rate of fill valves must be designed tablets and move large distances as possible.
And limits the distance to move each of the valve camshaft, and requirements for obtaining quiet operation, and the dynamic forces that are generated when you run the valves.
Requires filling rate in women with high-speed engines take into account not to endanger the mixture of fuel and air drawn only for the least possible choking when it passed section of the valve open.
Design and dimensions of springs valves used in the lock so that the cam track the movement of the valves without wobble (twitching), even at high speeds. Although the exposure of the exhaust valves for high temperatures, it should be characterized by their abilities to sit tight in their seats. This results in a thermal expansion valve stems. Therefore you must leave all clearance mechanisms play a timing of the movement to ensure the tightness of valves and to prevent leakage on its way, and reaches this conclusion on average to 0.3 mm for the intake valves and exhaust valves, a hot. To set the clearance provided levers or arms vacillating central control or screws.
If the intake valve clearance plus the limit, you will not be a fill rate of cylinder, air-fuel mixture enough. It also concluded that the excess in the exhaust valve leading to trap for waste hot gases and impeding the expulsion enough.
Can be excessive in the sense of drawing the levers by Alastkakah sounds that you hear when you spin the engine. If the clearance is less than the necessary levers lock the valves not be enough, leading to burned quickly, and in this case frequent repairs. Therefore should be reviewed by the sensor clearance cranes (Filr).
Cause a severe shortage in the clearance in the lock count tighten the valve. The amount drawn on the degree of heat and the length of the valve stem, and when you adjust the valves must be maintained on the clearance specified in the specifications of the factory product.
And requires the most appropriate rate to fill the cylinder to the intake valve is opened quickly - any connection to the valve to the maximum distance to move as quickly as possible - and that remains open for a long time, then quickly closed again.
Differ in how to control the valves in case of vertical inverted valves. The geometry of the space compression of the most important factors that determine the maximum rate of benefit to reach the highest value for the compression, and thus the quality of the performance of the engine. Also that the order of the valves of the important factors.
We have already argued that the way control valves arranged in vertical order of less complex in design, but maligned caused a decrease in fill rate of the engine due to the change in the direction of gas flow.
This defect may prevent the valves in order upside down, resulting in the throws of filling rate significantly. But the order of the valves in this situation - if any - would require a larger number of components.
There are two models of valves distinct inverted:
First-class works by camshaft located in a box attached.
Second-class works by Acod cam Alawi.
In the case of a camshaft mailbox facility replaces the vertical arm of the valve is working to pay to move the crane scales in proportion with (first-class lever) complex in Ras Alstoanat (Osh cylinder) and affect the way the valve. And provide the leverage Z side of the movement is derived from the control arm of the payment Mgulwz slotted screw head, nut and allow adjusting the valve clearance.
And moving the valve is in its index and Return Elá mainly how the same work in the case of vertical valves. While arranged valves that are controlled by the arms payment in a row side by side in a longitudinal direction of the cylinder head (Osh cylinder), arranged valves that operate by the upper camshaft usually in a position diagonally to the outside.
And justify the extra costs in many cases the best performance, which is accessed in this manner to control, which allows to reach higher speeds with a quiet and smooth running of the engine and control mechanisms.
After long periods of operation of the engine oil, carbon deposits formed on the exhaust vents are on the narrow corridors of the burned gases significantly, which affects the timing of the movement. Therefore, the exhaust vents should be cleaned after every 10000-20000 km of operation, and stop the amount of oil, carbon deposits mainly on the method of leadership, and stresses the engine incident, the type of oil mixed with fuel.
Yai and the LED is the only part which limits the possibility of increasing the speed to 8000 RPM. Although designed as spiral, which is characterized by strong and relatively short in length, but Zbzbath become inappropriate if the speed increased so much.
As a result of gross twitching, then, can not lock the valve from the right way, and possibly - in addition to that - Elá refraction in this range of speed.
In order to overcome these difficulties, which occur especially in women with high capacity engines, the producers come to the race car engines and the means by which lock the valve by the movement of anti-camshaft.
It is clear from the design camshaft described as a regular column that holds a number of cams and cam is a rise in one side of the column, and was able to open or lock the valve in accordance with the format.
The valve is blocked as a result of pressure Aaah. And provides each valve of the intake valves or exhaust alalia one is determined and set according to the timing of the open or lock it, and derives camshaft movement of the crankshaft by gears or a chain (Katana) or a vertical column is transferred to the movement of the crankshaft by gears conical or gear toothed italic.
And the proportion of interlock is 2: 1, that if any did the crankshaft two full laps of the camshaft has completed one lap and opening through which both the intake valve and exhaust valve once.
