What are the work on the power system. Purpose, device and operation of the supply system fuel. Power supply systems and exhaust gases of the car engine

The main node of any car is its engine, which is used by the engine internal combustion (DVS). Depending on the fuel used, the types of engine power systems are also available, which are very important for normal operation of the motor.

Types of engine power systems

Depending on the fuel fluid used, the engines, and, consequently, the power systems can be divided into three main types:

• petrol;
• diesel;
• operating on gaseous fuel.

There are other species, but their use is very slightly.

In some cases, the classification of nutrition systems is not made by type of fuel, but according to the method of preparation and supplying a combustible mixture into the combustion chamber. In this case, these types are distinguished:

• carburetor (ejector);
• with forced injection (injection).

Carburetor system

Such a system is used for gasoline engines. It is based on the formation of an air-fuel mixture due to the permission created by the movement of the piston. The air is absorbed passively, stirred in a diffuser with sprayed fuel and enters the cylinder, where flammable with the help of spark plug. Such a mechanical method has a number of shortcomings, for example - big flow Fuel and complexity of design.

Forced injection

This system has become a logical continuation of the first and replaced it. Work is based on the forced supply of a dosed amount of fuel through the nozzle. Depending on the number of nozzles, injector types of engine power systems are distributed (the number of nozzles and cylinders is equal to) and centralized (one nozzle) injection.

The diesel engine has its own distinctive feature: fuel is supplied through the nozzle directly into the cylinder, where the air is absorbed separately. The ignition occurs due to the large pressure generated by the piston, so the candles are not applied.

Regardless of which system is applied on your car, the main malfunctions of the engine power system are usually associated either with insufficient flow of fuel, or with a violation of its feed adjustment. Therefore, to ensure reliable work it is necessary to carry out maintenance. For these purposes, all the necessary details and consumables you can purchase online at the store site at competitive prices. Save time and money with us!

Purpose, device and operation of the supply system fuel

The fuel engine power system is designed to place the fuel reserve by car, cleaning, spraying the fuel and the uniform distribution of it by cylinders in accordance with the order of the engine.

The KAMAZ-740 engine uses a separation type fuel system (i.e., high-pressure fuel pump functions and nozzles are separated). It includes (Fig. 37) Fuel tanks, fuel filter coarse cleaning fuel filter thin cleaningFuel pumping pump * low pressure, Handmade fuel pumping pump, high pressure fuel pump (TNVD) with an all-mode regulator and automatic fuel injection ahead, nozzles, high and low pressure fuel lines and control and measuring instruments.

Fuel from the fuel tank under the action of the vacuum generated by the fuel-pumping pump, through the filters of coarse and thin purification by low-pressure fueling powdles is supplied to the high pressure fuel pump. In accordance with the order of the engine (1-5-4-2-6-3-7-8), the TNVD submits fuel under high pressure and certain portions through the nozzles in the combustion chamber of the engine cylinders. Injectors fuel sprayed. Excess the fuel, and with them and the air in the system through the ottld valve and the valve-fat valve of the fine cleaning filter are discharged into the fuel tank. Fuel surceded through the gap

Fig. 37. Fuel engine power system:
1 - fuel tank; 2 - fuel line to coarse filter; 3 - tee; 4 - Filter of coarse fuel purification; 5 - drain drainage fuel line injectors of the left row; 6 - nozzle; 7 - Sliding fuel line to low pressure pump; 8 - high pressure fuel pipe; 9 - manual fuel pumping pump; 10 is a top-level low pressure pump; 11 - fuel line to fine filter; 12 - high pressure fuel pump; 13 - fuel line to the electromagnetic valve; 14 - electromagnetic valve; / 5-drain drainage fuel line injectors of the right row; 16 - flare candle; P - drainage fuel pipeline of high pressure pump; 18 - Filter of fine fuel purification; 19 - Supporting fuel line to high pressure pump; 20 - drainage fuel filter fuel pipeline; 21 - drain fuel line; 22 - distribution crane

Fig. 38. Fuel tank:
1 - bottom; 2 - partition; 3 - body; 4 - plug crane; 5 - bulk tube; 6 - plug of bulk pipe; 7-second tape; 8 - Bracket Bracket Bracket

Fuel tanks (Fig. 38) are intended for accommodation and storage by car defined. Fuel supply. The KAMAZ-4310 car has two tanks with a capacity of 125 liters each. They are located on both sides of the car on the spars of the frame. The tank consists of two halves, stepped out of sheet steel and connected by welding; For corrosion protection, it is overwritten from the inside.

Inside the tank there are two partitions that serve to mitigate hydraulic fuels of fuel on the wall when the car is moving. The tank is equipped with a filling neck with a pull-out pipe, a filter grid and a hermetic lid. At the top of the tank, the fuel indicator sensor of the fuel level of the fuel is installed, a tube performing the role of an air valve. At the bottom of the tank, the intake tube and a fitting with a crane for draining sludge. At the end of the intake tube there is a strainer.

Filter of coarse fuel purification (Fig. 39) is intended for pre-purification of the fuel entering the fuel supply pumping pump. Mounted on the left side on the car frame. It consists of a housing, a reflector with a filter grid, a distributor, a sedator, a glass of filter, applying and discharge fittings with gaskets. A glass with a lid is connected by four bolts through a rubber sealing "JU gasket. A drain plug screws into the lower part of the glass.

The fuel coming through the tubing tank fitting is supplied to the distributor. Large extraneous particles and water are collected at the bottom of the glass. From the upper part of the fuel through the mesh filter, it is supplied to the discharge piece, and from it to the fuel supply pumping pump.

Filter of fine fuel purification (Fig. 40) is designed for final fuel purification before entering it into a high-pressure fuel pump. The filter is installed in the rear of the engine at the highest point of the power system. Such an installation provides air collection that has fallen into the system, and its removal in the fuel tank through the magnifier valve. The filter consists of a housing,

two filtering elements, two caps with welded rods, valve-gibera, supplying and discharge fittings with sealing gaskets, seal elements. The housing is cast from aluminum alloy. It contains channels for supplying and removing fuel, cavity to install valve-gibber and ring poles for installing the caps.

Replaceable cardboard filter elements are made of highly porous Cardboard type ETFS. The end seal of the elements is carried out by the upper and lower seals. The dense fit of the elements to the filter housing is provided by springs installed on the rods of the caps.

The magnifier valve is designed to remove air in the system. It is installed in the filter housing and consists of a cap, the springs of the valve, cork, adjusting washer, sealing washer. The fat valve opens when the pressure in the cavity in front of the valve is equal to 0.025 ... 0.045 MPa (0.25 ... 0.45 kgf / cm2), and at a pressure of 0.22 ± 0.02 MPa (2.2 ± 0.2 kgf / cm2) Begins torture fuel.

The fuel under pressure from the fuel-pumping pump fills the inner cavity of the cap and is pushed through the filter element, mechanical impurities remain on the surface. Purified fuel from the inner cavity of the filter element is supplied to the intake cavity of the pump.

Fig. 39. Filter of coarse fuel purification:
1 - drain plug; 2 - a glass; 3 - sedative; 4 - Mesh filtering; 5 - reflector; 6 - distributor; 7 - bolt; 8- flange; 9-ring sealing; 10 - housing

The low-pressure fuel pumping pump is designed to supply fuel through coarse and thin cleaning filters to the intake cavity of the TNVD. Piston type pump with drive from eccentric cam shaft TNVD. Pressure supply 0.05 ... 0.1 MPa (0.5 ... 1 kgf / cm2). The pump is installed on the back cover of the TNVD. The fuel pumping pump (Fig. 41, 42) consists of a housing, piston, piston springs, piston pusher, pusher rod, pusher springs, rod sleeve guide, inlet valve, injection valve.

Pig-iron pump housing. It contains channels and cavities for piston and valves. The cavities under the piston and above the piston are connected by the channel through the injection valve.

The pusher is designed to transmit effort from the eccentric cam shaft piston. Roller-type pusher.

The eccentric cam shaft of the pump through the pusher and the rod informs the piston of the pump (see Fig. 41) a reciprocating movement.

Fig. 40. Filter of fine fuel purification:
1 - body; 2 - bolt; 3 - sealing washer; 4 - traffic jam; 5, 6 - gaskets; 7 - element filtering; 8 - Cap; 9 - spring filter element; 10 - drain plug; 11 - Rod.

When lowering the pusher, the piston under the action of the spring moves down. In the suction cavity, it creates a vacuum, the inlet valve opens and passes the fuel into the above-piston cavity. At the same time, fuel from the pouring cavity through a fine cleaning filter enters the intake Channels of the TNVD. When the piston moves up the ink valve closes and fuel from the pickup cavity through the injection valve enters the cavity under the piston. When the pressure in the injection line B rises, the piston stops after the pusher move down, but remains in a position that is determined by the equilibrium of the forces from the fuel pressure on one side and the spring force on the other. Thus, the piston does not full, and partial. Thus, the performance of the pump will be determined by fuel consumption.

Manual fuel pumping pump (see Fig. 42) Designed to fill the fuel system and remove air from it. The piston type pump is attached on the housing of the brawl pump through the sealing copper puck.

The pump consists of a housing, piston, cylinder, piston rod and handle, support plate, inlet valve (total with a fuel pumping pump).

Filling and pumping the system is carried out by the movement of the handle with the rod up-down. When the handle is moving up in the rowing space, a vacuum is created. The intake valve opens and fuel enters the cavity above the piston of the fuel pumping pump. When the handle moves down, the fuel-pumping pump discharge valve opens and fuel under pressure enters the injection line. Next, the process is repeated.

After pumping, the handle must be tightly screwed onto the top threaded cylinder shank. In this case, the piston is yarring to the rubber gasket, sealing the inlet cavity of the fuel-pumping pump.

Fig. 41. Scheme of the fuel-pumping pump of low pressure and manual fuel pumping pump:
1 - Eccentric Drive Drive; 2 - pusher; 3 - piston; l - intake valve; 5 - manual pump; 6 - Purpose 4 Valve

The high pressure fuel pump (TNVD) is designed to supply dosage portions of fuel under high pressure into the engine cylinders in accordance with the order of their work.

Fig. 42. Fuel pumping pump:
1 - Eccentric Drive Drive; 2 - roller pusher; 3 - case (cylinder) pump; 4 - spring pusher; 5 - rod of the pusher; 6 - Stem sleeve; 7 - piston; 8 - Piston Spring; 9 - High Pressure Pump Corps; 10 - inlet valve seat; 11- Housing of low pressure fuel pumping pump; 12 - inlet valve; 13 - Valve Spring; / 4 - manual pumping pump; 15 - washer; 16 - the plug of the discharge valve; 17 - the spring of the discharge valve; 18 - low pressure fuel pump discharge valve

Fig. 43. High pressure fuel pump: 1 - rear regulator cover; 2, 3 - the leading and intermediate gear of the regulator of the frequency of rotation; 4- driven gear of the regulator with cargo holder; 5 - cargo axis; 6 - cargo; 7-coupling of goods; 8 - Finger lever; 9 - corrector; 10 - lever of the springs of the regulator; 11 - Rake; 12 - rail sleeve; 13 - reduction valve; 14 - Reiki traffic jam; 15 - YUFTA fuel injection; 16 - cam shaft; 17, - pump housing; 18 - Pump section

The pump is installed in the collapse of the cylinder block and operates from the camshaft gear through the pump drive gear. The direction of rotation of the cam shaft from the drive side is right.

The pump consists of a housing, a cam shaft (see Fig. 43), eight pumping sections, an all-mode regulator of the rotational frequency, fuel injection and fuel pump drive coupling.

The TNLD housing is designed to place pump sections, cam shaft and rotational speed control. Molding from aluminum alloy, it contains inlet and cut-off channels and cavities for installation and fastening of pumping sections, cam shaft with bearings, gear of the controller drive, supplying and reducing fuel fittings. In the rear end of the pump housing, the lid of the regulator is attached, in which the low-pressure fuel pumping pump is located with the pumping pump of the fuel. On top of the lid, the fitting with the oil oil tube for lubricating the parts of the pump under pressure is screwed. The oil from the pump merges along the tube connecting the lower hole of the regulator cover with the hole in the block collapse. The upper cavity of the TNVD housing is closed with a lid (see Fig. 44), on which the control knob control levers and two protective casing of the pump fuel sections are located. The cover is installed on two pins and is fastened with bolts, and protective covers - with two screws. At the front end of the pump housing at the outlet from the shut-off channel, a fitting was screwed with a ball-type bypass valve supporting the excess fuel pressure in the pump 0.06 ... 0.08 MPa (0.6 ... 0.8 kgf / cm2). At the bottom of the pump housing, a cavity is made to install a cam shaft.

The cam tree is designed for the movement of pumping sections in plungers and ensuring a timely fuel supply to the engine cylinders. The cam shaft is made of steel. The working surfaces of the cams and the supporting necks are cemented to a depth of 0.7 ... 1.2 mm. Due to the co-circular design of the pump, the cam shaft has a smaller length and, therefore, has a higher rigidity. The shaft rotates in two tapered bearings, the internal roles of which are pressed on the shaft neck. The axial clearance of the cam shaft 0.1 mm is regulated by gaskets installed under the bearing cover. For sealing cam shaft in the lid there is a rubber cuff. At the front cone end of the cam shaft on the segment key, an automatic coupling of the fuel injection angle is installed. At the rear end of the cam shaft, a stubborn sleeve is mounted, the leading gear of the regulator assembly, and on the prismatic key - the flange of the leading gear of the regulator. The flange is made together with the eccentric of the fuel-powder pumping pump. The torque from the cam shaft on the leading gear of the regulator is transmitted through the flange through rubber crackers. When the cam shaft rotates, the force is transmitted to roller pushers and through the pushers' stains to plungers of pumping sections. Each pusher from rotation is fixed with a sukhara, the protrusion of which is included in the pump sliding groove. Due to changes in thickness, the fifth is regulated by the start of fuel supply. When installing the fifth of greater thickness, the fuel starts to be supplied earlier.

Fig. 44. Controller cover:
1 - Bolt of adjustment of the launcher; 2 - stop lever; 3 - Bol * regulation of the stop lever; 4 - bolt restrictions of the maximum rotational speed; 5 - control lever regulator (fuel pump rail); 6 - bolt restrictions of the minimum rotation frequency; I - work; IT - off

Pump section (Fig. 45, a) is a part of the high-pressure fuel pump, which is dosing and feeding the fuel to the nozzle. Each pump section consists of a corpurz, plunger pair, swivel sleeve, springs plunger, discharge valve, pusher.

The enclosure of the section has a flange, with which the section is attached on the heels, screwed into the pump housing. Holes in the flange under the studs have an oval shape. This allows you to rotate the pumping section to regulate the uniformity of the fuel supply by individual sections. When you turn the section counterclockwise, the cycle feed increases, clockwise decreases. In the section of the section, two holes are made for the passage of fuel from the channels in the pump to the holes in the plunger sleeve (A, B), the hole for installing the pin fixing the position of the sleeve and the plunger relative to the section of the section, and the slot for placing a swivel sleeve.

Plunger pair (Fig. 45, b) is the node of the pump section, directly intended for dosing and fuel supply. Plunger pair includes a plunger and plunger bushing. They represent a precision pair. Made from chromolibdden steel, are undergoed by quenching, followed by a deep cold processing to stabilize the properties of the material. Work surfaces of the bushings and plunger nitrate.

Fig. 45. Section of the high pressure fuel pump:
a - design; B - the upper part of the plunger pair; A - cavity of the fuel pump injection; B - cutoff cavity; 1 - pump housing; 2- pusher section; 3 - heel pusher; 4 - Spring: 5, 14-Plunger Section; 6, 13 - Plunger's sleeve; 7 - discharge valve; 8 - fitting; 9 - section of the section; 10 - shut-off edge of the screw groove of the plunger; 11 - Rake; 12 - Plunger Rotary Bushing

The plunger is a movable piece of plunger pair and performs the role of piston. The plunger in the upper part has axial drilling, two spiral grooves made from two sides of the plunger, and a radial drilling connecting the axial drilling and grooves. The spiral groove is designed to change the cycle supply of fuel due to the rotation of the plunger, and consequently, the grooves relative to the cut-off plunger sleeve. The rotation of the plunger relative to the sleeve is carried out by the fuel pump rail through the spikes of the plunger. There is a label on the outer surface of one spike. When assembling the section, the tag on the plunger spike and the slot in the case of the section to install the leash of the swivel sleeve must be on the one hand. The presence of the second groove provides the hydraulic unloading of the plunger from the side effort. Due to this, the reliability of the pump section is increasing.

The seal between the sleeve and the section of the section is provided by a ring of oil-resistant rubber installed in the annular groove of the sleeve.

The discharge valve and its saddle are made of steel, hardened and treated with deep cold. The valve and saddle are a precision pair, in which the replacement of one part on the same name from another set is not allowed.

The discharge valve is located at the upper end of the sleeve and pressed to the saddle of the spring. The saddle of the discharge valve is pressed to the sleeve of the plunger of the end surface of the fitting through the sealing textolite gasket.

Purchase valve of fungal type with cylindrical guide part. The radial opening with a diameter of 0.3 mm is used to adjust the cycle feed at the rotation frequency of the cam shaft 600 ... 1000 min-1. The adjustment is carried out by increasing the throttle action of the valve during the cut-off of the supply, as a result of which the amount of fuel flowing from the high pressure fuel line into the admisted space is reduced. High-pressure fuel supply unloading is carried out by moving when boarding the valve guide in the saddle channel. The upper part of the guide serves as a piston, sucking fuel from the fuel line.

Protective speed regulator. Internal combustion engines should operate on a given steady (equilibrium) mode characterized by constant speed crankshaft, coolant temperature and other parameters. Such a mode of operation can only be supported by equality of the engine torque of the engine torque resistance. However, during operation, this equality is often disturbed due to a change in the load or the specified mode, so the parameter value (rotational speed, etc.) is deviated from the specified. Regulation is applied to restore the impaired engine operation mode. Adjustment can be done manually by impact on the control body (fuel pump rail) or using a special device called automatic rotational speed regulator. Thus, the rotational speed controller is designed to maintain the crankshaft rotational speed driver by automatically changing the fuel cycle, depending on the load.

On the KAMAZ engine there is a seven-minded centrifugal regulator of the rotational speed of direct action. It is placed in the collapse of the TNVD case, and the control is displayed on the pump cover.

The regulator has the following elements (Fig. 46):
- specifying device;
- sensitive element;
- comparing;
- actuating mechanism;
- Controller drive.

The control device includes the control lever, the springs lever, the regulator spring, the knob of the regulator, the lever with the proofreader, the adjusting bolts of the speed of rotation frequency.

The sensitive element includes a regulator shaft with a cargo holding, loads with rollers, thrust bearing, the clutch of the regulator with fifth.

A comparing device includes the cargo coupling lever, with which the movement of the controller's coupling of the actuator (Raik) is transmitted.

The actuator includes the fuel pump rails, the rail lever (differential lever).

The drive of the regulator includes a leading gear of the regulator, the intermediate gear 6, the gear of the regulator, made in one integer with the shaft of the all-mode regulator.

To stop the engine there is a device in which the stop lever includes the break lever spring, the starting spring, the restriction bolt of the stop lever, the starting feed bolt.

Fuel management is controlled by foot and manual drives.

The rotation of the leading gear of the regulator is transmitted through rubber crowns. Sugari, being elastic elements, quenching oscillations associated with the uneven rotation of the shaft. The decrease in high-frequency oscillations leads to a decrease in the wear of the joints of the main parts of the regulator. From the leading gear, rotation to the slave gear is transmitted through an intermediate gear.

The driven gear is done at the same time with the cargo of cargo rotating on two ball bearings. When the maintenance of the cargo is rotated under the action of centrifugal forces, it is diverged and through the thrust bearing move the clutch, the coupling, resting in the finger, in turn, moves the cargo coupling lever.

The cargo coupling lever is mounted in one end on the axis of the regulator levers, another through the pin is connected to the fuel pump rail. The axis also attaches the lever of the regulator, the other end of which moves to the stop in the adjusting bolt of fuel supply. The cargo coupling lever affects the knob of the regulator through the corrector. The control lever regulator is rigidly connected to the lever of the springs of the regulator.

Fig. 46. \u200b\u200bRotation frequency regulator:
1 - rear cap; 2 - nut; 3 - washer; 4 - Bearing; 5 - adjusting gasket; 6 - gear intermediate; 7 - Laying the back cover of the regulator; 8 - Ring lock; 9- cargo holder; 10 - cargo axis; 11 - the bearing is stubborn; 12 - coupling; 13 - cargo; 14 - finger; 15 - corrector; 16 - Returning Spring Stay Lever; 17 - bolt; 18 - sleeve; 19 - Ring; 20 - springs lever regulator; 21 - Master's gear: 22 - Truck leading gear; 23 - Flange of the leading gear; 24 - Adjusting fuel supply bolt; 25 - Starting lever

The starting spring is attached to the starting spring lever and the rail lever. Reiki, in turn, are associated with swivel sleeves of pumping sections. Reducing the degree of non-uniformity of the regulator at the small frequencies of rotation of the crankshaft is achieved due to the change of the shoulder of the application of the supplement springs of the regulator to the lever of the regulator.

The increase in the sensitivity of the regulator is ensured by the quality processing of the driving surfaces of the movable parts of the regulator and the pump, reliable lubrication and the increase in the angular velocity of rotation of the cargo coupling by two times the path of the pump shaft due to the gear ratio of the drive gear of the regulator.

On the engine installed a rotational speed regulator with a smoke traffic, which is built into the cargo coupling lever. The corrector, reducing the fuel supply, reduces the engine smoke at the low speed of the crankshaft (1000 ... 1400 min).

Specified speed mode The engine operation is set by the control lever, which turns and through the springs lever increases its tension. Under the influence of this spring, the lever through the corrector affects the coupling lever, which moves the rails associated with the rotary sleeves of the plungers, up to increase the fuel supply. The crankshaft rotation frequency increases.

The centrifugal force of rotating goods through the stubborn bearing, the coupling and arm of the cargo couplings is transmitted to the fuel pump rail, which is connected to another rail through the differential lever. Moving the records of centrifugal power of goods causes a decrease in fuel supply.

Adjustable high-speed mode depends on the ratio of the power of the regulator's spring and centrifugal force of goods at the set rotation frequency of the crankshaft. The larger the springs of the regulator stretch, with higher high-speed mode, its loads can change the position of the regulator lever towards limiting the fuel supply to the engine cylinders. Sustained engine operation will be in the event that the centrifugal power of goods will be equal to the power of the springs of the regulator. Each position of the control lever of the regulator corresponds to a certain rotation frequency of the crankshaft.

At a given position of the control lever, in case of a reduction in the load on the engine (movement to the descent), the rotational speed of the crankshaft, and consequently, the drive shaft of the regulator rises. In this case, the centrifugal power of cargo increases and they disagree.

Loads affect the stubborn bearing and, overcoming the spring force specified by the driver, rotate the regulator lever and move the rails towards the reduction of the supply since the fuel supply is not established, which corresponds to the conditions of movement. The specified speed engine mode will be restored.

With an increase in the load (movement on the rise), the speed of rotation, and therefore, the centrifugal forces of goods decrease. The force of spring through the levers 31, 32, acting on the coupling, moves it and brings closer. In this case, the rails are moved towards an increase in fuel supply until the rotational speed of the crankshaft reaches the value specified by the conditions of movement.

Thus, the all-life regulator supports any driver mode set by the driver.

When the engine is operating at the nominal frequency of rotation and complete fuel supply, the M-shaped lever 31 rests on the adjusting bolt 24. In the event of an increase in the load, the speed of rotation of the crankshaft and the regulator shaft begins to decline. At the same time, the equilibrium between the power of the regulator spring and the centrifugal force of its cargo shown in the axis of the regulator lever is disturbed. And due to the excessive force of the springs of the corrector, the corrector plunger moves the coupling lever towards increasing the fuel supply.

Thus, the rotational speed controller not only supports the operation of the engine at a given mode, but also provides an additional fuel portion to the cylinders when working with overload.

Turning off the fuel (stop of the engine) is carried out by turning the stop lever until it stops in the stop lever adjustment bolt. The lever, overcoming the spring force (installed on the lever), will turn over the finger of the regulator lever. Rakes move until the fuel supply is completely shutdown. The engine stops. After stopping the stop lever under the action of the return spring returns to the position of work, and the starting spring through the rope lever will return the rails of the fuel pump in the direction of the fuel supply (195 ... 210 mm3 / cycle).

Automatic fuel injection advance coupling. In diesels, fuel is injected into the air charge. The fuel cannot instantly ignite, but should pass the preparatory phase, during which the fuel mixing with air and its evaporation is carried out. When the temperature of self-ignition reaches the mixture, the mixture flashes and quickly begins to burn. This period is accompanied by a sharp increase in pressure and increasing temperature. In order to get the highest power, it is necessary that the combustion of the fuel occurred in the minimum volume, i.e. when the piston is in the VMT. To this end, the fuel is always injected before the arrival of the piston in the NWT.

The angle determining the position of the crankshaft is relative to the NMT at the time of the start of the fuel injection, is called the fuel injection advance angle. The design of the fuel pump of the diesel engine KAMAZ provides the fuel injection 18 ° to the arrival of the piston in the NTT with compression tact.

With an increase in the rotational speed of the engine of the engine, the time for the preparatory process is reduced and the ignition can begin after the NTC, which will reduce useful work. In order to get the greatest work with an increase in the rotational speed of the crankshaft, the fuel must be injected before, i.e. increase the fuel injection advance. This can be done due to the rotation of the cam shaft in the direction of its rotation relative to the drive. For this purpose, a fuel injection coupling is installed between the fist of the pump and its drive. The use of the coupling significantly improves the launchers of the diesel engine and its economy at various speed modes.

Thus, the fuel injection advance guard coupling is intended to change the moment of fuel supply, depending on the rotational speed of the crankshaft of the engine.

The KAMAZ-740 applied an automatic centrifugal type of direct action. The adjustment range of the fuel injection ahead is 18 ... 28 °.

The coupling is installed at the conic end of the cam tree of the TNVD on the segment key and is fastened with a ring nut with a spring washer. It changes the fuel injection moment due to the additional rotation of the pump shaft during the engine operation relative to the high-pressure pump drive shaft (Fig. 47).

Automatic coupling (Fig. 47, a) consists of a housing, a leading coupling with fingers, a slave half-carmuft with the axles of cargo, cargo, springs, springs, springs, springs, adjusting gaskets and stubborn washers.

Cast iron coupling housing. Two threaded holes for filling the coupling are performed on the front end. motor Oil. The housing turns on the slave gunum and stops. The seal between the housing and the leading coupling and the hub, the slave, the semi-carrying is carried out by two rubber cuffs, and between the case and the slave-resistant-resistant rubber rings.

The host of the half-moupel is installed on the hub slave and can be rotated relative to it. The coupling drive is carried out from the drive shaft of the pump (Fig. 47, b). Two fingers are made in the leading half-finger on which spacers are installed. The spacer rests on one end into the finger of the cargo, and the other slides according to the profile of cargo.

The slave of the half-moupel is installed on the conical part of the fist of the TNVD. Two axes of cargo are pressed in the coupling and a label is applied to set the fuel injection ahead. Loads are swinging on the axes in the plane perpendicular to the axis of rotation of the coupling. In cargoes there are profile protrusions and fingers. On cargoes there are efforts of springs.

Fig. 47. Automatic fuel injection lifting coupling:
A - Automatic coupling: 1 - leading of the half; 2, 4 - cuffs; 3 - the bushing of the leading coupling; 5 - case; 6 - adjusting gasket; 7 - a glass of springs; 8 - spring; 9, 15 - washers; 10 - Ring; 11 - cargo with a finger; 12 - Betting with axis; 13 - slave of the half; 14 - sealing ring; 16 - cargo axis
b - automatic clutch drive and installing it by tags; 1 - label nya rear flange demummifs; II - label on the injection advance coupling; III - label on the fuel pump housing; 1 - automatic injection advance coupling; 2 - driven by the drive halfway; 3 - bolt; 4 - Flange Helmwood Drive

With a minimum rotation frequency of the crankshaft, the centrifugal force of goods is small and they are held in force of springs. In this case, the distance between the cargo axes (on the slave halfway) and the leads the leading half will be maximal. The led part of the coupling lags behind the leading to the maximum angle. Consequently, the fuel injection advance angle will be minimal.

With an increase in the speed of rotation of the crankshaft of goods under the action of centrifugal forces, overcoming the resistance of the springs, diverge. Spacers slide according to the profile protrusions of goods and turn around the axes of the fingers of the cargo. Since the position of the spacer includes the heads of the leading half, then the discrepancy of goods leads to the fact that the distance between the leading half-one's fingers and the cargo axes will decrease, i.e. will decrease the angle of the ledge of the demummouft from the lead. The slave of the half is turned relative to the leading corner in the direction of rotation of the clutch (direction of rotation of the right). The rotation of the slave. The highway causes the cam shaft of the TNVD, which leads to an earlier fuel injection relative to the NWT.

With a decrease in the rotation of the crankshaft engine, the centrifugal power of goods decreases and they begin to converge under the action of the springs. The slave of the coupling is rotated relative to the drive leading, opposite to rotation, reducing the fuel injection advance angle.

The nozzle is designed for the fuel injection into the cylinders "of the engine, spraying and distribution of it in terms of the combustion chamber. On the KAMAZ-740 engine, closed-type nozzles with a multi-stage sprayer and a hydraulically controlled needle are installed. The pressure of the wave of the needle 20 ... 22.7 MPa (200 ... 227 kgf / cm2). The nozzle is installed in the cylinder head socket and the bracket is fastened. The sealing of the nozzle in the nest of the cylinder head is carried out in the upper belt with the rubber ring 7 (Fig. 48), in the lower-cone of the spray nut and the copper washer. The nozzle consists of the housing 6, the nuts of the sprayer 2, the sprayer, spacers 3, the rods 5, the springs, the support and adjusting washers and the nozzle fitting with the filter.

The housing of the nozzle is made of steel. In the upper part of the housing, threaded holes are made to install the fitting with the filter and the fiber of the drainage pipeline (see Fig. 37). The housing includes a fuel supply channel and a channel for removing fuel, seeping into the inner cavity of the case.

Fig. 48. Nozzle:
a - with adjusting washers; bs outdoor adjustment; 1 - dispenser housing; 2 - Nut of the Sprayer; 3 - spacer; 4 - installation pins; 5 - rod; 6 - body; 7 and 16 - sealing rings; 8 - fitting; 9 - filter; 10 - sealing sleeve; 11 and 12 - adjusting washers; 13 - Spring; 14 - spray needle; 15 - focus of the spring;. 17 - Eccentric

The nut the sprayer is designed to connect the sprayer with the nozzle housing.

Sprayer - nozzle assembly, spraying and forming jets of injected fuel.

The housing of the sprayer and the needle make up a precision pair, in which the replacement of one part is not allowed. The housing is made of chromonicheladium steel and subjected to special heat treatment (cementation, quenching, followed by deep cold processing) to obtain high hardness and wear resistance of working surfaces. In the spray case, the ring groove and a channel for supplying fuel into the cavity of the spray case, as well as two holes for the pins, ensuring the fixing of the sprayer body relative to the nozzle housing. At the bottom of the housing, four nozzle holes are made. Their diameter is 0.3 mm. To ensure a uniform fuel distribution by volume of combustion chamber, the nozzle holes are made at different angles. This is due to the fact that the nozzle relative to the axis of the cylinder is at an angle of 21 °.

The sprayer needle is designed to lock the spray holes after the fuel injection. The needle is made of instrumental steel and also subjected to special processing. In order to increase the service life of the sprayer and the needle, the valorist of the needle is doubled.

The spacer is designed to fix the dispenser's housing relative to the nozzle body.

The rod is a movable part of the nozzle, designed to transmit effort from the springs of the nozzle to the needle of the sprayer.

Spring nozzle is designed to provide the needle lifting pressure. The springs tension is carried out by adjusting washers, which are installed between the support washer and the end of the inner cavity of the nozzle body. The change in the thickness of the washers 0.05 mm leads to a change in the pressure of the beginning of the needle lifting by 0.3 ... 0.35 MPa (3 ... 3.5 kgf / cm2). In second-type nozzles (Fig. 48,6), the spring adjustment is made by turning the eccentric 17.

Joint work of the pump section of the pump and the nozzle. The driver, affecting the fuel pedal through the system of the thrust and levers, specifying the device of the all-life regulator, the rails of the fuel pump, the swivel sleeves, rotates the plunger. Thus, sets a certain distance between the cutting hole and the shut-off edge of the screw groove, providing a specific cycle fuel supply.

The plunger under the action of the cam shaft makes a reciprocating movement. When the plunger moves down the discharge valve, loaded by the spring, is closed and a vacuum is created in the admixture cavity.

After opening the upper edge of the plunger of the inlet in the sleeve fuel from the fuel channel under a pressure of 0.05 ... 0.1 MPa (0.5 ... 1 kgf / cm2) from the fuel-blowing pump enters the admixture space (Fig. 49, a).

At the beginning of the movement (Fig. 49, b) of the plunger Up the fuel part is displaced through the intake and shut-off holes in the fuel supply channel. The moment of the start of the fuel supply is determined by the moment of overlapping the inlet of the sleeve of the upper edge of the plunger. From this point on, when the plunger is moving up, the fuel is compressed in the admixture cavity, and after reaching the pressure at which the injection valve opens, in the high pressure pipeline and the nozzle.

Fig. 49. Scheme of the pump section:
a - filling of the admixture cavity; b - the beginning of the feed; in - end of filing

When the fuel pressure in the specified cavity becomes more than 20 MPa (200 kgf / cm2), the sprayer needle rises up and opens the fuel access to the nozzle holes of the sprayer, through which the fuel injection under high pressure in the combustion chamber occurs.

When the plunger moves up, when the cut-off edge of the screw groove reaches the level of the cut-off opening, the end of the fuel supply is occurring (Fig. 49, a). With the further movement of the plunger up the admixture cavity through the vertical channel, the diametrical channel, the screw groove is reported to the shut-off channel. As a result of this, the pressure in the admixture cavity drops, the injection valve under the action of spring and fuel pressure in the pump fitting sits in the saddle and the flow of fuel to the nozzle stops, although the plunger can still move up. With a decrease in the pressure in the fuel line below the force being created, the sprayer needle under the action of the spring is lowered down and overlaps the access of fuel to the nozzle holes of the sprayer, thereby terminating the fuel supply to the engine cylinder. Extraked through the clearance in a pair of needle - the body of the sprayer fuel is discharged through the channel in the housing of the nozzle to the drainage pipeline and then in the fuel tank.

On all modern cars with petrol engines Used injector system Fuel supply, since it is more perfect than carburetor, despite the fact that it is structurally more complex.

Injection engine is not new, but he received widespread only after the development of electronic technologies. All because mechanically organize the management of the system with a high accuracy of work was very difficult. But with the advent of microprocessors, it became quite possible.

The injection system is characterized in that gasoline is fed strictly specified portions forcibly into the collector (cylinder).

The main advantage that the injector power system has, is the observance of the optimal proportions of the composite elements of the combustible mixture on different modes Work power plant. This achieves the best power outlet and economical consumption of gasoline.

System device

The injector fuel supply system consists of electronic and mechanical components. The first controls the work parameters power aggregate And based on them gives signals to trigger the executive (mechanical) part.

The electro-controller includes the electro component ( the electronic unit Management) and a large number of tracking sensors:

• crankshaft positions;
• mass flow of air;
• throttle positions;
• detonation;
• coolant temperatures;
• air pressure in the intake manifold.

Injectors system sensors

Some cars can have several more additional sensors. All of them have one task - to identify the parameters of the operation of the power unit and transmit them to the ECU

As for the mechanical part, it includes such elements:

• electric fuel pump;
• fuel lines;
• filter;
• pressure regulator;
• fuel ramp;
• nozzle.

Simple injector fuel supply system

How everything works

Now consider the principle of operation of the injection engine separately for each component. With an electronic part, in general, everything is simple. Sensors collect information about the speed of rotation of the crankshaft, air (entered into the cylinders, as well as the residual part of its exhaust gases), the position of the throttle (associated with the accelerator pedal), the temperature of the coolant. These data sensors are constantly transmitted to the electronic unit, due to which the high accuracy of the dosage of gasoline is achieved.

ECU information incoming from sensors compares with data entered in the maps, and on the basis of this comparison and a number of settlements performs the executive part of the executive part. In the electronic unit made so-called cards with optimal parameters The operation of the power plant (for example, it is necessary to submit so much gasoline to such conditions, to others - so much).

First injector Engine Toyota 1973

In order to be clearer, consider in more detail the electronic block operation algorithm, but according to the simplified scheme, since in reality, a very large amount of data is used in the calculation. In general, all this is aimed at calculating the temporal length of the electrical pulse, which is fed to the nozzles.

Since the scheme is simplified, then suppose that the electronic unit conducts calculations only in several parameters, namely the basic time length of the pulse and two coefficients - the temperature of the coil and the oxygen level in the exhaust gases. To obtain the result, the ECU uses a formula in which all available data is variable.

To obtain the base length of the pulse, the microcontroller takes two parameters - the rotation speed of the crankshaft and the load, which can be calculated by pressure in the collector.

For example, the engine turnover is 3000, and the load 4. The microcontroller takes these data and compares with the table entered in the map. In this case, we obtain the basic temporal length of the pulse of 12 milliseconds.

But for calculations, it is also necessary to take into account the coefficients, for which the testimony from the temperature sensors and the lambda probe is taken. For example, the temperature is 100 degrees, and the oxygen level in the exhaust gases is 3. The computer takes these data and compares with several more tables. Suppose that the temperature coefficient is 0.8, and the oxygen - 1.0.

Having obtained all the necessary data the electronic unit is calculated. In our case, 12 multiply by 0.8 and 1.0. As a result, we obtain that the impulse should be 9.6 milliseconds.

The described algorithm is very simplified, in fact, during the calculations, not one dozen parameters and indicators can be taken into account.

Since the data goes to the electronic unit constantly, the system almost instantly responds to a change in the parameters of the motor operation and adjusts to them, providing optimal mixing formation.

It is worth noting that the electronic unit controls not only the fuel supply, the ignition angle adjustment is also included in its task to ensure optimal operation of the motor.

Now about the mechanical part. Here everything is very simple: the pump installed in the tank pumps gasoline into the system, and under pressure to ensure forced feed. The pressure must be defined, therefore the regulator is turned on in the diagram.

On highways, gasoline is fed to the ramp, which connects all the nozzles among themselves. The electrical pulse served from the computer leads to the opening of the nozzles, and since the gasoline is under pressure, then it is simply injected through the opened channel.

Types and types of injectors

Injectors are two species:

1. With one-point injection. Such a system is outdated and on cars is no longer used. Its essence is that the nozzle is only one installed in the intake manifold. This design did not provide a uniform distribution of fuel in the cylinders, so its work was similar to the carburetor system.
2. Multipoint injection. On modern cars, this type is used. Here, for each cylinder, its nozzle is provided, therefore such a system is characterized by high dosage accuracy. The nozzles can be installed both in the intake manifold and in the cylinder itself (injection).

On the multipoint injector fuel supply system, several types of injection can use:

1. Simultaneous. In this type, the impulse from the ECU comes immediately to all the nozzles, and they open together. Now this injection is not used.
2. Pair, he is pairwise-parallel. In this type of nozzles work in pairs. Interestingly, only one of them serves fuel directly in the intake tact, the second beat does not coincide. But since the engine is 4-stroke, with a valve gas distribution system, then the incompression of the injection on the cycle on the performance of the motor of the influence does not.
3. Phased. In this type, the ECU gives signals to the opening for each nozzle separately, so the injection occurs with the coincidence on the tact.

It is noteworthy that the modern injector fuel supply system can use several injection types. So, in the usual mode, a phased injection is used, but in the case of a transition to emergency operation (for example, one of the sensors refused), the injection engine goes into a pair injection.

Feedback with sensors

One of the main sensors, on the testimony of which the ECU regulates the opening time of the nozzles, is a lambda probe installed in the exhaust system. This sensor determines the residual (not burnt) the amount of air in the gases.

Evolution of the Lambda Probe Sensor from Bosch

Thanks to this sensor, the so-called "feedback" is ensured. Its essence is this: ECU has spent all the calculations and filed momentum on the nozzles. The fuel came, mixed with air and burned down. Formed traffic fumes With not burnt particles, the mixture is displayed from cylinders over the removal system exhaust gasesin which the lambda probe is installed. Based on its testimony, the ECU determines whether all calculations were performed correctly and when necessary, adjusts adjustments to obtain optimal composition. That is, based on the already conducted stage of supplying and combustion of fuel, the microcontroller makes the calculations for the next.

It is worth noting that in the process of the power plant, there are certain modes in which the testimony oxygen sensor It will be incorrect that can disrupt the motor operation or a mixture with a certain composition. With such modes, the ECU ignores information from the lambda probe, and the signals for the supply of gasoline it sends, based on the information laid.

In different modes, feedback works like this:

• Running motor. In order for the engine to get started, a rich combustible combustible mixture is needed with an increased percentage of fuel. And the electronic unit provides, and for this it uses the specified data, and it does not use information from the oxygen sensor;
• Wait. So that the injection engine scored faster operating temperature ECU sets the increased turnover of the motor. At the same time, it constantly controls its temperature, and as it warm up it adjusts the composition of the combustible mixture, gradually its dinner until its composition becomes optimal. In this mode, the electronic unit continues to use the data specified in the maps, still using the lambda probe testimony;
• Idling. In this mode, the engine is already completely warm, and the temperature of the exhaust gases is high, so the conditions for the correct operation of the lambda probe are respected. The computer is already beginning to use the testimony of an oxygen sensor, which allows you to establish the stoichiometric composition of the mixture. This composition provides the greatest power output of the power plant;
• Movement with a smooth change of motor revolutions. To achieve an economical fuel consumption at the maximum power output, a mixture with stoichiometric composition is needed, so with this mode, the ECU regulates the supply of gasoline based on the testimony of the lambda probe;
• A sharp increase in revolutions. So that the injection engine reacted normally on such an action, you need a somewhat enriched mixture. To ensure it, the ECU uses card data, and not the indications of the lambda probe;
• Motor braking. Since this mode does not require power output from the motor, it is enough that the mixture simply did not give to stop the power plant, and for this it will fit and the depleted mixture. For its manifestation of testimony, the lambda probe is not needed, so the ECU does not use them.

As can be seen, the lambda probe is although it is very important to work the system, but the information from it is not always used.

Finally, we note that the injector is though a constructive complex system and includes a plurality of elements whose breakage immediately affects the operation of the power plant, but it provides a more rational consumption of gasoline, and also increases the ecology of the car. Therefore, there is no alternative to this system yet.

The power system is an integral part of any internal combustion engine. It is designed to solve the tasks listed below.

□ Fuel storage.

□ Cleaning fuel and feeding it into the engine.

□ Air purification used to prepare a combustible mixture.

□ Preparation of a combustible mixture.

□ Feed a combustible mixture into the engine cylinders.

□ The withdrawal of exhaust (exhaust) gases into the atmosphere.

Supply system a passenger car Includes the following elements: fuel tank, fuel hoses, fuel filter (there may be several), fuel pump, air filter, carburetor (injector or other device used to prepare a combustible mixture). Note that in modern cars, carburetors are used quite rarely.

The fuel tank is located at the bottom or in the rear of the car: these places are most safe. The fuel tank is connected to the instrument that creates a fuel mixture, by means of fuel hoses that pass almost through the entire car (usually - on the bottom of the body).

However, any fuel must pass a preliminary cleaning, which may include several degrees. If you pour fuel from the canister - use a funnel with a mesh filter. Remember that gasoline has more fluidity than water, so it is possible to use very small grids for filtering, in which cells are almost not visible. If your gasoline contains a water intake, then after filtering through a thin mesh, the water will remain on it, and the gasoline is leaking.

Cleaning the fuel when pouring it into the fuel tank is called preliminary cleaning or first degree of cleaning - because on the way of fuel to the engine, it will still be a similar procedure.

The second degree of cleaning is performed using a special grid located on the fuel intake inside the fuel tank. Even if at the first stage of purification in the fuel remained some impurities, they will be removed in the second stage.

For the highest quality (fine) fuel purification entering the fuel pump, a fuel filter is used (Fig. 2.9), located in motor compartment. By the way, in some cases the filter is installed before, and after the fuel pump - in order to improve the quality of purification of the fuel entering the engine.

Important.

The fuel filter should be changed every 15,000 - 25,000 km of run (depending on the particular brand and model of the car).

To ensure fuel supply to the engine, the fuel pump is used. Usually it includes the following details: housing, a diaphragm with a drive mechanism and spring, intake and exhaust (injection) valves. Also in the pump there is another net filter: it provides the last, fourth fuel purification step before serving it into the engine. Among other parts of the fuel pump, we note the rod, the injection and suction pipe, the lever of manual swap fuel, etc.

The fuel pump can be activated from the oil pump drive roller or from the engine camshaft. When rotating any of these shafts, the eccentric stands on them puts pressure on the rod of the fuel pump drive. The rod, in turn, presses on the lever, and the lever - on the diaphragm, as a result of which the one goes down. After that, the diaphragm is formed a discharge, under the influence of which the inlet valve overcomes the spring force and opens. As a result, a certain portion of the fuel is sucked from the fuel tank into space above the diaphragm.

When the eccentric "releases" the rod of the fuel pump, the lever ceases to put pressure on the diaphragm, as a result of which the springs of the spring rises upwards. In this case, pressure is formed, under the action of which the intake valve is tightly closed, and the injection valve opens. The fuel above the diaphragm is sent to the carburetor (or another device used to prepare a combustible mixture - for example, an injector). When eccentric once again begins to put pressure on the rod, the fuel is absorbed and the process is repeated anew.

However, it should be cleaned not only fuel, but also air used to prepare a combustible mixture. To do this, use a special device - air filter. It is installed in a special case after the air intake and is closed with a lid (Fig. 2.10).

Air, passing through the filter, leaves on it the entire garbage contained, dust, impurities, etc., and for the preparation of a combustible mixture is used already in purified.

Remember this.

Air filter is consumable materialIt should be changed through a certain space (usually 10,000 - 15,000 km). The flooded filter makes it difficult to pass through it. It becomes the cause of fuel overpower, since the combustible mixture will contain a lot of fuel and little air.

Purified combustible mixture components (gasoline and air) each expensive enter the carburetor or other device specifically designed to create a combustible mixture of gasoline and air vapor. The finished mixture is supplied to the engine cylinders.

Note.

The carburetor automatically adjusts the composition of the combustible mixture (the ratio of gasoline and air vapor), as well as its number supplied to the cylinders, depending on the mode of operation of the engine (idling, measured riding, acceleration, etc.). As we have already noted earlier, on modern cars, carburetors are rarely used (electronics controls everything, the most famous such device is an injector), but Soviet and russian cars (VAZ, AZLK, GAZ, ZAZ) were produced with a carburetor. Since half-Russia goes on such cars today, we will further consider in detail the principle of operation and the carburetor device.

Carburetor (Fig. 2.11) consists of a large number of different parts and includes a number of systems required for stable work Engine.

The key elements of the typical carburetor are: a float chamber, a hexed shut-off valve float, a mixing chamber, a sprayer, an air damper, throttle, diffuser, fuel and air canals with gibeles.

In general, the principle of the production of a combustible mixture in the carburetor looks like this.

When the piston at the inlet in the cylinder of the combustible mixture begins to move from VTM to NMT, the discharge is formed above it in accordance with the laws of physics. Accordingly, the air jet after pre-cleaning with air filter And passing through the carburetor enters this zone (in other words, it sues it).

When the purified air is passed through the carburetor from the float chamber through the sprayer, fuel is absorbed. This sprayer is located in the narrow point of the mixing chamber, called the "Diffuser". The incoming flow of purified air gasoline arising from the sprayer, as if "crushes", after which is mixed with air, and the so-called initial mixing occurs. The final mixing of gasoline with air is carried out at the outlet of the diffuser, and then the combustible mixture enters the engine cylinders.

In other words, in the carburetor to obtain a combustible mixture, the principle of a conventional pulverizer is used.

However, the motor will work stably and reliably only when in the carburetor float chamber, the gasoline level will be permanent. If it rises above the set limit, then in the mixture there will be too much fuel. If the gasoline level in the float chamber is below the set limit - the combustible mixture will be too poor. To solve this problem in the float chamber, a special float is intended, as well as a needle shut-off valve. When gasoline in the float chamber remains too small, the float is lowered together with a needle stop valve, thus allowing gasoline to flow into the chamber. When the fuel becomes enough, the float pops up and the valve overlaps the path of gasoline. To visually see this principle "in action", look at the work of a simple drain tank in the toilet.

The stronger the driver presses the gas pedal, the more the throttle is opened (in initial position It is closed). At the same time, more gasoline and air enters the carburetor. The more the driver goes the gas pedal, the stronger the throttle is closed, and less gasoline and air flows into the carburetor. The motor is less intensively (inclusive), so the torque transmitted to the car's wheels is reduced, respectively - the car reduces the speed.

But even with the full release of the gas pedal (and closing the throttle), the motor will not stall. This is explained by the fact that when the engine is working on idling Another principle applies. The essence of it is that the carburetor is equipped with channels specifically designed to penetrate the air to penetrate the throttle, mixing on the way with gasoline. With closed throttle valve (at idle) air is forced to enter the cylinders through these channels. At the same time, he "sucks" gasoline from the fuel channel, mixes with it, and this mixture enters the subsidement. In this space, the mixture finally takes the desired state and enters the engine cylinders.

Note.

For most engines when working at idle, the optimal rotation speed of the crankshaft is 600-900 revolutions per minute.

Depending on the current mode of operation of the motor, the carburetor prepares a fuel mixture of the required quality. In particular, when the cooled motor, the combustible mixture must contain more fuel than when the engine is working. It is worth noting that the most economical engine mode is a flat ride on the highest transmission at a speed of about 60-90 km / h. When driving in this mode, the carburetor creates a depleted combustible mixture.

Note.

Automotive carburetors can have different models and execution options. Here we will not bring the description of carburetors different modificationsSince we have enough to have at least a general idea of \u200b\u200bthe work of the carburetor. Detailed information on how the carburetor functions in a particular car can be found in the instruction manual and repair of this car.

As we have already noted above, in the process of the internal combustion engine, exhaust gases are formed. They are the combustion product of the working mixture in the engine cylinders.

It is the exhaust gases from the cylinder during the last, the fourth tact of its working cycle, which is called - the release. Then they are output to the atmosphere. To do this, in each car there is a mechanism for exhaust gases, which is part of the power system. Moreover, its task is not only the removal of them from cylinders and the release into the atmosphere, which itself, but also a decrease in noise, which is accompanied by this process.

The fact is that the release of exhaust gases from the engine cylinder is accompanied by very loud noise. It is so strong that without a silencer (a special device absorbing noise, Fig. 2.12) The operation of cars would be impossible: near the working car it would be impossible because of the noise produced by them.

The mechanism of exhaust gases of the standard car includes the following composite elements:

□ exhaust valve;

□ graduation channel;

□ Pipes of the muffler (on the driver's slang - "pants");

□ Additional silencer (resonator);

□ main muffler;

□ Connecting clamps with which parts of the muffler are connected to each other.

In many modern cars, besides listed elements, a special exhaust gas neutralization catalyst is also used. The name of the device speaks for itself: it is designed to reduce the number harmful substancescontained in car exhaust gases.

The mechanism of exhaust gases works quite simply. From the cylinders of the engine, they enter the muffler's receiving pipe, which is connected to an additional silencer, and the one, in turn, with the main silencer (the end of which is the exhaust pipe, protruding the back of the car). The resonator and the main muffler inside have a rather complicated structure: so there are numerous holes, as well as small cameras that are located in a checker order, as a result of which a complex tangled labyrinth is formed. When exhaust gases pass through this labyrinth, they reducing their speed and go out of exhaust pipe Practically silently.

It should be noted that the car's exhaust gases contain many harmful substances: carbon monoxide (the so-called carbon monoxide), nitrogen oxide, hydrocarbon compounds, etc. Therefore, never warm the car in a closed room - it is deadly: very many cases have known when people died in own garages from carbon monoxide.

Food system operation modes

Depending on the purpose and road Conditions The driver can apply different modes of motion. They are consistent with certain modes of operation of the power system, each of which is inherent in the fuel and air mixture of special quality.

1. The composition of the mixture will be rich in the start of the cold engine. At the same time, air consumption is minimal. In this mode, the possibility of movement is categorically eliminated. Otherwise, this will lead to increased consumption of fuel and wear of the force aggregate details.
2. The composition of the mixture will be enriched when using the mode " idle move", Which is used when moving" rolling "or the operation of the engine of the engine in a heated state.
3. The composition of the mixture will be depleted when moving with partial loads (for example, on a flat road with an average speed at increased transmission).
4. The composition of the mixture will be enriched in full load mode when the car is moving at high speed.
5. The composition of the mixture will be enriched, approximate to the rich, when driving under sharp acceleration (for example, when overtaking).

The choice of the operating conditions of the power system, thus, should be justified by the need to move in a certain mode.

Malfunctions and service

In the process of operation vehicle The fuel system of the car is experiencing loads leading to its unstable functioning or failure. The most common are the following malfunctions.

Insufficient receipt (or lack of admission) fuel in engine cylinders

Elected-quality fuel, long service life, environmental impact leads to contamination and clogging of fuel pipelines, tank, filters (air and fuel) and technological holes of the combustible mixture device, as well as a breakdown of the fuel pump. The system will require the repair that will be to enter into timely replacement Filtering elements, periodic (once every two or three years), clean the fuel tank, carburetor or injector nozzles and replacing or repairing the pump.

Loss of power of the economy

The fuel system malfunction in this case is determined by the violation of the quality adjustment and the amount of combustible mixture entering the cylinders. The elimination of malfunction is associated with the need to diagnose the combustible mixture preparation device.

Fuel leak

Fuel leakage - the phenomenon is very dangerous and categorically not allowed. This malfunction is included in the "List of faults ...", with which the movement of the car is prohibited. Causes of problems are losing in the loss of tightness with nodes and fuel system units. The elimination of malfunction is either in replacing the damaged elements of the system, or in tightening fasteners of fuel pipelines.

Thus, the power system is an important element of DVS modern car And responsible for timely and uninterrupted fuel supply to the power unit.