Diesel engines for trucks and tractors. Spare parts, adjustments and repairs.
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Maintenance of the fuel system of the Kamaz-740 diesel engine
The fuel supply system (fuel system) of KAMAZ-740 ensures fuel purification and its uniform distribution over the engine cylinders in strictly metered portions. The engines use a split-type fuel supply system, consisting of a high-pressure fuel pump, injectors, coarse and fine filters, a low-pressure fuel priming pump, low-pressure and high-pressure fuel lines, fuel tanks, an electromagnetic valve and torch spark plugs of an electric torch starter. A schematic diagram of the Kamaz-740 fuel system is shown in fig. 1. Fuel from the tank 1 through the coarse filter 2 is sucked in by the fuel priming pump and through the fine filter 17 through the low pressure fuel lines 3, 9, 15, 21 is supplied to the high pressure fuel pump; according to the order of operation of the engine cylinders, the pump distributes fuel through high-pressure pipelines 6 to injectors 5.
Rice. 1. Scheme of the fuel system of the Kamaz-740 engine 1 - fuel tank; 2 - coarse fuel filter; 3-pipe fuel supply to the low pressure pump; 4 — tube fuel drainage nozzles of the left heads; 5 - nozzle; 6 - high pressure fuel pipe; 7 - low pressure fuel priming pump; 8 - manual fuel priming pump; 9 - fuel outlet tube of the low pressure pump; 10 - high pressure fuel pump; 11 - solenoid valve; 12-fuel tube to the solenoid valve; 13 - torch candle; 14 — tube fuel drainage nozzles of the right heads; 15 - fuel supply tube injection pump; 16 - fuel outlet tube injection pump; 17 - fuel fine filter; 18 - fuel fine filter tube; 19 - tee for fastening fuel pipes; 20 - fuel drain tube; 21 - fuel line to the coarse filter; 22 - intake pipe with filter Nozzles spray and inject fuel into the combustion chambers. Excess fuel, and with it the air that has entered the fuel system, is discharged into the fuel tank through the bypass valve of the high-pressure fuel pump and the jet valve of the fine filter through drain fuel lines 16 and 18. The fuel that has leaked through the gap between the sprayer body and the needle is drained into the tank through the drain fuel lines 4, 14, 20. The coarse filter (sump) Kamaz-740 (Fig. 2) pre-cleans the fuel entering the low pressure fuel priming pump. Rice. 2. Coarse fuel filter Kamaz-740 1 - plug; 2 - glass; 3 - calmer; 4 - filter mesh; 5 - reflector; 6 - distributor; 7 - bolt; 8 - flange; 9 - sealing ring; 10 - housing The coarse filter is installed on the suction line of the power supply system on the left side of the vehicle on the frame. Cup 2 is connected to the body 10 with four bolts 7 and sealed with a ring 9. A drain plug 1 is screwed into the boss of the cap from below. The fuel coming from the fuel tank through the inlet fitting flows into the glasses. Large particles and water collect at the bottom of the glass. From the upper part, through the filter mesh 4, through the outlet fitting and fuel lines, fuel is supplied to the fuel priming pump. The Kamaz-740 fine filter (Fig. 3), which finally cleans the fuel before it enters the high-pressure fuel pump, is installed at the highest point of the fuel system to collect and remove air that has penetrated into the fuel system together with part of the fuel through the jet valve, into the tank, installed in housing 1. Fig. 3. Fine fuel filter KAMAZ-740 1 - body: 2 - bolt; 3 - sealing washer; 4 - plug; 5, 6 - sealing gaskets; .7 - filter element; 8 - cap; 9 – filter element spring; 10 - drain plug; 11 - rod The beginning of the shift of the jet valve 4 (Fig. 4) occurs at a pressure in the cavity of 24.5 ... 44.1 kPa (0.25 ... pressure in cavity A 196.2 ... 235.3 kPa (2.0 ... 2.4 kgf / cm2). The valve is adjusted by selecting shims 1 inside the valve plug.
Rice. 4. Valve-jet of the fuel fine filter KAMAZ-740 1 - adjusting washer; 2 - valve plug; 3-spring; 4 - jet valve Fuel lines are divided into low pressure fuel lines 392… 1961 kPa (4… 20 kgf/cm2) and high pressure more than 19614 kPa (200 kgf/cm2). High-pressure fuel lines of the fuel system are made of steel tubes, the ends of which are made cone-shaped, pressed with union nuts through washers to the conical sockets of the fuel pump fittings and injectors. The fuel lines are secured with brackets and brackets to prevent damage from vibration. Fuel pump high pressure fuel pump Kamaz-740 diesel High pressure fuel pump (high pressure fuel pump) KAMAZ-740 is designed to supply strictly metered portions of fuel under high pressure to the engine cylinders at certain points in time. Eight sections are installed in the injection pump housing (Fig. 5), each consists of a housing 17, a bushing 16 of the plunger 11, a rotary bushing 10, a discharge valve 19, pressed through the sealing gasket 18 to the plunger bushing by the fitting 20. The plunger reciprocates under the action shaft cam 44 and spring 8. Fig. 5. Fuel pump KAMAZ-740 1 - housing; 2, 32 - pusher rollers; 3, 31 - axes of the rollers; 4 - roller bushing; 5 - heel of the pusher; 6 - cracker; 7 — a plate of a spring of a pusher; 8 - pusher spring: 9.34.43.45, 51 - washers; 10 - swivel bushing; 11 - plunger; 12, 13, 46, 55 - sealing rings; 14 - mounting pin; 15 - rail; 16 - plunger bushing; 17 - section body; 18 - pressure valve gasket; 19 - pressure valve; 20 - fitting; 21 - flange of the section body; 22 - manual fuel priming pump; 23 - spring plug; 24, 48 - gaskets; 25 - housing of the low pressure pump; 26 - low pressure fuel pump; 27 - stem bushing; 28 - pusher spring; 29 - pusher; 30 - locking screw; 33, 52 - nuts; 35 - low pressure pump drive eccentric; 36, 50 - dowels; 37 - flange drive gear regulator; 38 - cracker of the drive gear of the regulator; 39 - drive gear of the regulator; 40 - thrust bushing; 41, 49 - bearing caps; 42 - bearing; 44 - cam shaft; 47 - cuff with spring assembly; 53 - fuel injection advance clutch; 54 - tube rail; 56 - bypass valve; 57 - rack bushing; 58 — the axis of the lever rails; 59 - adjusting shims The pusher from turning in the fuel pump housing is fixed with a cracker 6. The cam shaft rotates in roller bearings 42 installed in the covers and attached to the pump housing. The axial clearance of the cam shaft is regulated by gaskets 48. The value of the clearance should be no more than 0.1 mm. To increase the fuel supply, the plunger 11 is rotated by the sleeve 10 connected through the axis of the leash to the rail 15 of the pump. The rail is mixed in the guide bushings 57. Its protruding end is closed with a plug 54. On the opposite side of the injection pump there is a screw that regulates the fuel supply by all sections of the pump. This screw is plugged and sealed. Fuel is supplied to the pump through a special fitting, to which a low-pressure pipe is attached with a bolt. Further, through the channels in the housing, it enters the inlet holes of the bushings 16 of the plungers. At the front end of the Kamaz-740 fuel pump housing and at the fuel outlet from it, a bypass valve 56 is installed, which opens at a pressure of 58.8 ... 78.5 kPa (0.6 ... 0.8 kgf / cm2). The opening pressure of the valve is adjusted by selecting shims inside the valve plug. Pump lubrication is circulating, under pressure from the general engine lubrication system. The turbocharged engine is equipped with a fuel pump with increased injection energy, with an anti-smoke corrector and a nominal cyclic fuel supply of 96 mm3 / cycle. The speed regulator of the high-pressure fuel pump KAMAZ-740 is all-mode, direct-acting, it changes the amount of fuel supplied to the cylinder depending on the load, maintaining the set frequency. The regulator is installed in the collapse of the body of the Kamaz-740 high-pressure fuel pump. The drive gear 21 of the regulator is installed on the cam shaft of the high-pressure fuel pump, the rotation of which is transmitted through rubber crackers 22. The driven gear is made integral with the holder 9 of the weights, rotating on two ball bearings. When the holder rotates, the loads 13, swinging on the axes 10, diverge under the action of centrifugal forces and the clutch 12 is moved through the thrust bearing 11. The clutch, resting against the pin 14, in turn moves the lever 32 of the cargo clutch. Lever 32 is fixed at one end to axis 33, and at the other end is connected to rail 27 through a pin. Lever 31 is fixed to axis 33, the other end of which moves all the way into the adjusting bolt 24 of the fuel supply. Lever 32 transmits force to lever 31 through corrector 15. Fuel supply control lever 1 (Fig. 7) is rigidly connected to the lever. The spring 26 is attached to the levers 20, 31, the starting spring 28 is attached to the levers 25, 30. During the operation of the regulator in a certain mode, the centrifugal forces of the weights are balanced by the force of the spring 26. Fig . 7. Cover of the speed regulator Kamaz-740 1 - control lever of the fuel supply regulator; 2 — a bolt of restriction of the minimum frequency of rotation; 3 - stop lever; 4 - filler plug; 5 - bolt for adjusting the starting feed; 6 — a bolt of restriction of a course of the stop lever; 7 — a bolt of restriction of the maximum frequency of rotation; I - work; II - off With an increase in the frequency of rotation of the crankshaft of the regulator, overcoming the resistance of the spring 26, the weights move the lever 32 of the regulator - the fuel supply decreases. With a decrease in the speed of the crankshaft, the centrifugal force of the loads decreases, and the lever 32 of the regulator with the rail of the fuel pump under the action of the force of the spring will move in the opposite direction - the fuel supply and the speed of the crankshaft increase. The fuel supply is turned off by turning the stop lever 3 (see Fig. 7) until it stops against the bolt 6, while lever 3, having overcome the force of the spring, will turn levers 31 and 32 through pin 29; the rail will move until the fuel supply is completely turned off. When the force is removed from the stop lever under the action of the spring, the lever will return to its working position, and the starting spring 16 through the lever 30 will return the fuel pump rail to the position of the maximum fuel supply required for starting. Low-pressure fuel pump and fuel priming pump KAMAZ-740 The low-pressure fuel pump KAMAZ-740 of piston type is designed to supply fuel from the tank through a coarse and fine filter to the inlet cavity of the high-pressure pump. The pump is mounted on the rear cover of the regulator. In housing 25 (see Fig. 5) there is a piston, a piston spring, a bushing 27 of the rod and a pusher rod, in the housing flange there is an inlet valve and a valve spring. The eccentric of the camshaft through the roller 32, the pusher 29 and the rod informs the piston of the fuel priming pump reciprocating motion. The scheme of operation of the low pressure pump is shown in fig. 8. When the pusher is lowered, the piston 10 moves down under the action of the spring 4. A vacuum is created in the suction cavity A, and the intake valve 1, compressing the spring 2, passes fuel into the cavity. Rice. Fig. 8. Scheme of operation of the low-pressure fuel pump and the Kamaz-740 manual fuel priming pump 1 - inlet valve; 2, 4, 5, 9 - springs; 3 - piston of a manual fuel priming pump; 6 - pusher; 7 - eccentric; 8 - delivery valve; 10 - piston; And — a cavity of absorption; B - injection cavity: C - supply to the fuel pump; E - supply from the fuel coarse filter At the same time, the fuel in the discharge cavity B is forced into the line, bypassing the discharge valve 8, connected by channels to both cavities. In the free position, the discharge valve closes the channel of the suction cavity. When the piston 10 moves upwards, the fuel that has filled the suction cavity enters the cavity B under the piston through the discharge valve 8, while the inlet valve 1 closes. With an increase in pressure in the discharge line, the piston does not make a full stroke after the pusher, but remains in a position that is determined by the balance of forces from the fuel pressure on one side, from the spring force on the other side. The fuel priming hand pump fills the system with fuel and removes air from it. The piston type pump is mounted on the flange of the low pressure fuel pump with a sealing copper washer. The Kamaz-740 fuel priming pump consists of a body, a piston, a cylinder, a handle assembly with a rod, a support plate and a seal. The power system is pumped by moving the handle with the rod and piston up and down. When the handle moves upwards, a vacuum is created in the under-piston space. The inlet valve 1, compressing the spring 2, opens, and the fuel enters the cavity A of the low pressure fuel pump. When the handle moves down, the discharge valve 8 opens, and fuel under pressure enters the discharge line. After pumping, screw the handle onto the upper threaded shank of the cylinder. In this case, the piston will press against the rubber gasket, sealing the suction cavity of the low pressure fuel pump. The automatic fuel injection advance clutch KAMAZ-740 (Fig. 9) changes the start of the fuel supply depending on the engine crankshaft speed. Rice. 9. Clutch automatic advancing fuel injection KAMAZ-740 1 — half-coupling leading; 2.4 - cuffs; 3 - bushing of the leading coupling half; 5 - body; 6-adjusting gaskets; 7 — a glass of a spring; 8 - spring; 9, 15 - washers; 10 - ring; 11 - load with a finger; 12 - spacer with an axis; 13 - driven half-coupling; 14 - sealing ring; 16 — axis of loads The use of a clutch provides the start of fuel supply, optimal for the working process, over the entire range of speed modes. This ensures the efficiency and acceptable rigidity of the process in various speed modes of the engine. The driven half-coupling 13 is fixed on the conical surface of the front end of the camshaft of the fuel pump with a key and a nut with a washer, the driving half-coupling 1 is fixed on the hub of the driven half-coupling (it can turn on it). A bushing 3 is installed between the hub and the coupling half. Weights 11 swing on axles 16, pressed into the driven coupling half, in a plane perpendicular to the axis of rotation of the coupling. The spacer 12 of the leading half-coupling rests with one end against the pin of the load, with the other end against the profile ledge. The spring 8 tends to keep the load against the stop in the sleeve 3 of the leading coupling half. With an increase in the crankshaft rotational speed, the loads diverge under the action of centrifugal forces, as a result of which the driven coupling half rotates relative to the leading one in the direction of rotation of the camshaft, which causes an increase in the fuel injection advance angle. When the crankshaft speed decreases, the loads converge under the action of the springs, the driven coupling half rotates together with the pump shaft in the direction opposite to the direction of shaft rotation, which causes a decrease in the advance angle of the fuel supply. Diesel injector Kamaz-740 Nozzle Kamaz-740 (Fig. 10) of a closed type with a multi-hole atomizer and a hydraulically controlled needle. All parts of the injector are assembled in housing 6. Fig. 10. Nozzle KAMAZ-740 1- spray body; 2-atomizer nut; 3 - sprayer spacer; 4 - dowel pins; 5 – nozzle rod; 6 - nozzle body; 7 - sealing ring; 8 - fitting; 9, 10 - adjusting washers; 11 - nozzle spring; 12 Spacer 3 and body 1 of the atomizer, inside which there is a needle, are attached to the lower end of the nozzle body with a nut 2. The body and needle of the atomizer are a precision pair. The atomizer has four nozzle holes. Spacer 3 and body 1 are fixed relative to the body with pins. The spring 11 rests at one end against the rod 5, which transmits force to the sprayer needle, and at the other end against the stop. Fuel is supplied to the nozzle under high pressure through fitting 8. Further, through the channels of body 6, spacer 3 and body 1 of the atomizer, fuel enters the cavity between the atomizer body and the needle and, squeezing it out, is injected into the cylinder. The fuel leaking through the gap between the needle and the atomizer body is discharged through the channels into the nozzle body. The nozzle is installed in the head, cylinder and secured with a bracket. The end face of the atomizer nut is sealed against gas breakthrough with a corrugated washer. The sealing ring protects the cavity between the nozzle and the cylinder head from dust and water. On a turbocharged engine, a model 271 injector with increased fuel capacity and a nozzle hole diameter of 0.32 mm. KAMAZ-740 engine fuel supply control drive KAMAZ-740 fuel supply control drive (Fig. 11) is mechanical, with a telescopic pusher, consists of a pedal, rods, levers and transverse rollers. There is also a manual drive for fuel supply and engine shutdown. The pedal 13 of the fuel supply is connected to the control lever 7 of the speed controller. Rice. 11. KAMAZ-740 fuel supply control drive 1 - engine stop rod handle; 2 - the handle of the thrust of manual control of the fuel supply; 3, 10 - rear levers; 4 - thrust of the regulator control lever; 5 - injection pump; 6 - engine stop lever; 7-lever control regulator; 8 - transverse roller; 9 - rear bracket; 11- telescopic rod; 12 - pedal bracket; 13 - pedal; 14 — adjusting bolt Handles of remote control rods of the engine are installed in the cab on a bracket in the lower part of the panel: left 2 — to turn on the constant fuel supply, connected by a flexible cable in a protective sheath to the control lever of the speed controller; right 1 - to stop the engine, connected by a cable to the engine stop lever, which is located on the cover of the speed controller.
Features of the operation of the high-pressure fuel pump manufactured by YAZDA for Kamaz Euro vehicles
The high technical complexity and cost of the high-pressure fuel pump requires attention to the assembly, which guarantees long-term uninterrupted operation of both the diesel equipment itself and the engine. In general, during operation, you must pay attention to the following points:
- every day you need to remove the sludge formed in the coarse filter;
- after 20,000 kilometers, fine fuel filters must be installed;
- regularly check the tightening torque of the bolt securing the drive coupling to the gear shaft in the crankcase of the devices and, if necessary, tighten;
- control and eliminate, if necessary, leaks in the elements of the fuel system;
- perform timely maintenance of the high-pressure fuel pump itself and flush the injectors both with the help of additives and with a special stand;
- use only high-quality diesel fuel, in which there are no impurities and water.
It is also important to know the main symptoms of problems with the YAZDA injection pump installed on KAMAZ Euro 2 class, which will prevent costly repairs or even replacement of the unit. It is necessary to pay attention to the node and diagnose the following symptoms:
- increase in fuel consumption;
- fuel leaks;
- power reduction;
- unstable operation of the motor;
- problems with starting the engine;
- black smoke from the exhaust pipe;
- extraneous noise in the injection pump.
Most often, problems with the pump arise due to uneven fuel supply, which occurs against the background of wear of the main elements of the system (discharge valves, plunger pairs, nozzle clogging, failure of plunger wiring). Another cause of the malfunction is the delay in the moment of fuel injection, which is associated with the wear of the sockets of the wheel housing, the roller axis and other elements of the high-pressure fuel pump. The most serious problem is the sticking of the rack due to dirt, corrosion under the action of water in the fuel.
Source
Mixing and fuel combustion
The formation of the working mixture begins from the moment a dose of fuel is injected into the combustion chamber.
The combustion chamber (fig. 1.) is limited by the piston crown and the inner surface of the cylinder head.
Such combustion chambers are called undivided. The main volume of the chamber is concentrated in the recess of the piston bottom, which has a cone-shaped protrusion (displacer) in the central part.
When the piston approaches top dead center (TDC) in the compression stroke, the air from the cylinder is forced into the combustion chamber, creating vortex flows during movement, which contribute to better mixture formation.
By the time the fuel injection begins, this chamber contains air compressed to 4 ... 4.5 MPa and heated (from compression and the hot chamber wall) to a temperature of 620 ... 700 ° C.
In order for the fuel to penetrate into such a compressed medium, it is injected under a high pressure of 24 MPa. This allows you to get a fine atomization of the fuel and good mixing with air.
A feature of a diesel engine is that the same amount of air actually enters the cylinder, regardless of the load.
At low load, excess air is formed in the cylinder and the fuel burns completely.
With an increase in load, the fuel supply increases and its combustion worsens.
The ignition delay period affects the behavior of the engine. It depends both on the properties of the fuel itself and on the temperature in the combustion chamber and the injection advance angle.
Too large an injection advance angle leads to an increase in the ignition delay period and "hard" engine operation, since in this case the injection starts at relatively low temperatures in the cylinder.
A small advance angle contributes to the combustion of fuel in the expansion stroke, which worsens the temperature regime of the engine, causing it to overheat.
For a non-working KamAZ engine, the injection advance angle is 18 ° to c. m. t.
On a running engine, as the crankshaft speed increases, the pressure and temperature at the end of the compression stroke increase, so the conditions for mixture formation and combustion change.
The duration of the combustion process increases and in this case it is advisable to increase the injection advance angle.
The increase in the angle is carried out automatically by the injection advance clutch, which acts on the high pressure fuel pump when a certain crankshaft speed is reached.
The diagram of the KamAZ diesel power supply system is shown in Fig. 2. The fuel is contained in tank 1, which is connected by a suction fuel line through a coarse filter 2 to a low pressure fuel pump 7.
When the engine is running, a vacuum is created in the suction line, as a result of which the fuel passes through the coarse filter 2, is cleaned of large suspended particles and enters the pump 7, from which it is fed under low pressure through the fuel line 9 to the fine filter 17.
Further, the purified fuel enters the high-pressure fuel pump 10, from the channels of which part of the fuel is pumped to the injectors 5 and injected into the cylinders through them.
The other part of the fuel through the bypass valve is diverted to the tank.
Due to the operation of the bypass valve, a pressure of 50 ... 110 kPa is constantly maintained in the pump channels.
To remove air that has entered the fuel system, the fine filter 17 is located above all other devices of this system and is equipped with a jet valve through which air, together with part of the fuel, is discharged through the fuel line 18 to the tank.
Through the same fuel line, fuel is drained into the tank from the high-pressure pump 10, which enters the fitting on the filter through the bypass valve and fuel line 16.
Fuel lines 4 and 14 are used to drain fuel that has leaked between the parts of the nozzles into the tank.
The high pressure pump is driven by the engine crankshaft through an injection advance clutch that automatically changes the fuel injection timing when the engine speed changes.
The amount of fuel supplied to the cylinders by the high-pressure fuel pump is set by the regulator, which automatically maintains the crankshaft speed set by the driver.
The manual fuel priming pump 8 serves to fill the low-pressure line with fuel when the engine is not running.
A fuel line 12 is connected to the low-pressure line, through which fuel enters the flare candles 13 through an open solenoid valve 11 when starting a cold engine using an electric torch device.
740.70-1104000 Installation of fuel lines - KAMAZ-65111 (Euro 4):
4 4 4 4 4 6 6 6 6 6 6 6 8 10 12 14 16 16 18 20 22 24 26 28 28 28 30 32 34 36 40 42 44 48 50 52 54 56 56 58 62 64 66 66 68 68 72 72 74 76 82 84 86 86 88 88 88 88 88 88 88 90 92 94 94 96 98 100 100 100 102 104 106 108 108 108 108 108 108 110 112 114 116 120 122 124 126 128 128 130
List of components from 740.70-1104000 Installation of fuel lines on KAMAZ-65111 (Euro 4)
Parts diagrams are for reference only! We sell not all spare parts from 740.70-1104000 Installation of fuel lines for KAMAZ-65111 (Euro 4) presented in this list. If there is a link "Show prices" in the right column , these spare parts from "740.70-1104000 Installation of fuel lines" are on sale. Availability in warehouses for details with the price, see the product card. If there is no “Show cost” link in the right column, we do not sell such parts and do not accept orders for them.
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| 4 | 740-70-1104232 | Fitting assembly | 3 | Show prices | ||
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Chapter 6.8 Fuel supply system KamAZ-740
6.8 FUEL SUPPLY SYSTEM
The fuel supply system ensures fuel filtration and its uniform distribution over the engine cylinders in metered portions at strictly defined moments.
The engine uses a split-type fuel supply system, consisting of a fuel tank, low-pressure fuel lines, coarse and fine fuel filters, fuel priming and priming pumps, a high-pressure fuel pump (HFP) with a stop solenoid, high-pressure fuel lines, injectors, an electromagnetic valve and pin candles of the electric torch device (EFD).
The fuel tank, the fuel coarse filter and the fuel priming pump must be installed on the product on which the engine is used, all other elements of the power system are installed directly on the engine.
The scheme of the engine fuel supply system is shown in Figure 42.
Figure 42. Engine fuel supply system: 1 - 8 - high pressure fuel lines; 9 — tube fuel drainage nozzles of the left heads; 10 - nozzle; 11 — tube fuel drainage nozzles of the right heads; 12 - fuel outlet tube high pressure fuel pump; 13 - fuel outlet tube; 14 - fuel supply tube injection pump; 15 - solenoid valve EFU; 16 - fuel fine filter; 17 - candle EFU; 18 - fuel priming pump; 19 - fuel tube to the solenoid valve; 20 - fuel tube from the solenoid valve to the EFU candles; 21 - injection pump; 22 - tee; 23 - valve; 24 - bypass valve injection pump; 25 - pneumatic cylinder stop the engine; 26 - fuel tank; 27 - filler neck with strainer; 28 - fuel intake tube with a strainer; 29 - coarse fuel filter; 30 - fuel priming pump.
Fuel from the fuel tank 26 through the coarse filter 29 and the fuel priming pump 30 is supplied by the fuel priming pump 18, through the fuel pipe 13 to the fine filter 16. From the fine filter, through the low pressure fuel pipe 14, the fuel enters the injection pump 21, which, in accordance with distributes fuel through the high pressure fuel lines 1-8 to injectors 10 in the order of cylinder operation. The injectors inject fuel into the combustion chambers. Excess fuel, and with it the air that has entered the system, is discharged through the bypass valve 24 and valve 23 into the fuel tank.
The nozzle type 273 of a closed design, with five sawing holes and hydraulically controlled lifting of the spray needle, is shown in Figure 43. All parts of the nozzle are assembled in body 6. The body 1 of the sprayer is pressed to the lower end of the body of the nozzle with a nut 2 through spacer 3, inside which there is a needle 12. The body and needle of the atomizer are a precision pair. The angular fixation of the atomizer body relative to the spacer and the spacer relative to the nozzle body is carried out by pins 4. Spring 11 exerts pressure on the upper end of the atomizer needle through the rod 5. The necessary tension of this spring is carried out by a set of adjusting washers 9, 10, installed between the spring and the end face of the inner cavity of the nozzle body.
Fuel is supplied to the injector at high pressure through fitting 8 with a slotted filter 13 built into it, then through the channels of housing 6. spacers 3 and atomizer body 1 - into the cavity between the atomizer body and needle 12 and, raising it, is injected into the engine cylinder.
The fuel leaking through the gap between the needle and the atomizer body is discharged through the channels in the nozzle body and drains into the tank through drain pipes 9 and 11, shown in Figure 42. The nozzle is installed in the cylinder head, fixed with brackets, which are fixed with a nut. The end face of the atomizer nut is sealed against gas breakthrough with a corrugated copper gasket. The sealing ring 7 (Figure 43) protects the cavity between the nozzle and the cylinder head from dust and liquids.
Figure 43. Nozzle: 1 - sprayer body; 2 - atomizer nut; 3 - spacer; 4 - pins; 5 - nozzle rod; 6 - nozzle body; 7 - sealing ring; 8 - nozzle fitting; 9, 10 - adjusting washers; 11 - nozzle spring; 12 - spray needle; 13 - slotted filter.
ATTENTION!
Checking and adjustment of nozzles, as well as replacement of nozzles, must be carried out in a specialized workshop.
It is strictly forbidden to install injectors of other models, except for those specified in the instructions, due to the possibility of engine failure.
The high-pressure fuel pump (Figure 44) is designed to supply strictly metered portions of high-pressure fuel to the engine cylinders at certain moments.
Figure 44. High pressure fuel pump (TNVD 337-20) with a fuel priming pump: 1 - high pressure fuel pump housing; 2 - pusher; 3 - pusher spring; 4 - rotary sleeve; 5 - rail; 6 - housing section of the high-pressure fuel pump; 7 - plunger; 8 - plunger sleeve; 9 - sealing ring; 10 — a saddle of the delivery valve; 11 - delivery valve; 12 - fitting; 13 - fuel priming pump; 14 - cracker; 15 - pusher; 16 - drive gear of the regulator; 17 - cracker drive gear; 18 - drive gear flange; 19 - eccentric of the fuel priming pump; 20 - rear regulator cover; 21 - intermediate cover of the regulator; 22 - intermediate regulator gear bearing; 23 - screw for adjusting the cyclic fuel supply; 24 - fuel supply corrector for charge air pressure; 25 - regulator cover bearing; 26.44 - shims; 27 - bearing holder loads; 28 - holder of goods; 29 - cargo axis; 30- thrust bearing of the regulator clutch; 31 - cargo; 32 - regulator clutch; 33 - return spring of the stop lever; 34 - finger; 35 - direct corrector; 36 - top cover of the regulator; 37 - regulator spring lever; 38 - bypass valve; 39 - tube rail; 40 - rack bushing; 41 - cuff; 42 - flange of the driven half-coupling; 43 - driven half-coupling; 45 - camshaft bearing; 46 - cam shaft; 47 - stem bushing; 48 - pusher rod; 49 - roller.
An injection pump model 337-20 with an all-mode regulator is installed on an automotive equipment engine.
An injection pump model 337-71 with a two-mode regulator is installed on the bus configuration engine.
The injection pump plunger diameter is -11 mm, the plunger stroke is -13 mm, the discharge valve is fungal, with a feather diameter of 7 mm without unloading.
Eight sections are installed in the injection pump housing 1, consisting of a housing 6, a plunger bushing 8, a plunger 7, a rotary bushing 4, an injection valve 11 with a seat 10, a fitting 12 pressed against the plunger bushing. The plunger reciprocates under the action of the shaft cam 46 and springs 3 pushers. The pusher 2 from turning in the housing is fixed with a cracker 14. The cam shaft rotates in roller bearings 45. The outer races of the bearings are installed in steel rings pressed into the pump housing. From axial movement, the cam shaft is fixed by covers. The tension of the camshaft bearings is regulated by gaskets 44 and should be 0.05 ... 0.15 mm.
To change the fuel supply, the plunger 7 is rotated with the help of a sleeve 4 connected through the axis of the leash to the rail 5 of the pump. The rail moves in the guide bushings 40. The holes for the guide bushings in the high-pressure fuel pump housing on the drive side are closed with plugs 39. On the opposite side of the pump, on the rear cover 20 of the regulator, there is a fuel supply corrector for charge air pressure 24.
At the front end of the housing, at the place where the fuel exits the pump, a bypass valve 38 is installed, which provides pressure in front of the inlet holes of the plungers in operating modes of 0.13 ... 0.19 MPa (1.3 ... 1.9 kgf / cm2). The lubrication of the pump is circulating, under pressure from the general lubrication system of the engine.
High-pressure fuel pump mod. 337-20 (Figure 45) all-mode, direct action, changes the amount of fuel supplied to the cylinders depending on the load, maintaining a given crankshaft speed.
Figure 45. High-pressure fuel pump regulator (top view): 1 - corrector for fuel supply according to charge air pressure; 2 - rail lever; 3.11 - slats; 4 - the lever of the starting spring; 5 - the main spring of the regulator; 6 - starting spring; 7 - rack lever; 8 - regulator lever; 9 - cargo clutch lever; 10 - axis; 12 - reverse corrector; 13 - screw for adjusting the cyclic fuel supply; 14 - pin.
The regulator is installed in the collapse of the injection pump housing. The drive gear 16 (Figure 44) is installed on the cam shaft of the pump, the rotation of which is transmitted through rubber crackers 17. The driven gear is made integral with the weight holder 28, rotating on two ball bearings. When the holder rotates, the loads 31, swinging on the axes 29, diverge under the action of centrifugal forces and move the regulator clutch 32 through the thrust bearing 30, which, resting against the pin 34, in turn, moves the levers 2, 8 and 9 of the regulator (Figure 45), overcoming the force of spring 5. Lever 2 is connected through a pin to the right rail 3 of the fuel pump. The right rail through the rail lever 7 is connected to the left rail 11.
The operation diagram of the speed controller is shown in Figure 46.
Figure 46. Scheme of operation of the speed controller: 1 - injection pump rail; 2 - cargo clutch lever; 3 - reverse corrector spring; 4 - rack lever; 5 - holder of goods; 6 - adjusting bolt for fuel supply; 7 - fuel supply corrector according to boost fuel pressure; 8 - membrane; 9 - regulator lever; 10 - direct corrector spring; 11 - rack lever; 12 - spring lever; 13 - regulator spring; 14 - the lever of the starting spring; 15 - starting spring; 16 - regulator control lever.
The regulator control lever 16 is rigidly connected to the lever 12. The regulator spring 13 is connected to the lever 12, and the starting spring 15 is connected to the levers 14 and 11.
During the operation of the regulator, the centrifugal forces of the loads are balanced by the force of the spring 13. With an increase in the crankshaft speed, the loads, overcoming the resistance of the spring 13, move the levers 2, 4 and 9, and with them the injection pump rails - the fuel supply decreases. With a decrease in the crankshaft speed, the centrifugal force of the loads decreases, and the levers with the injection pump rail under the action of the spring force move in the opposite direction - the fuel supply and the crankshaft speed increase.
When the lever 9 of the regulator rests against the bolt 6 and the crankshaft speed is less than 1800 min-1, the spring 10 of the direct corrector moves the pump rails (through levers 2 and 4) in the direction of increasing the fuel supply, providing the required value of the maximum engine torque.
The spring 3 of the reverse corrector at a speed of less than 1400 min-1 moves the lever 4 with the rails in the direction of reducing the fuel supply, limiting the maximum smoke of the exhaust gases of the engine.
The fuel supply is stopped by turning the lever 3 (Figure 47) to stop the engine until it stops in the bolt 5. The lever is turned by the force of the spring built into the engine stop solenoid 6 when the holding winding of the electromagnet is disconnected from the power source (the key of the lock of the instrument switch and the starter in the fixed position "0" ). At the same time, lever 3, having overcome the forces of springs 33 (Figure 44) and 5 (Figure 45), will turn levers 2,9 and 8 through pin 14, the rails will move until the fuel supply is completely cut off.
Figure 47. High pressure fuel pump regulator cover: 1 - regulator control lever; 2 — a bolt of restriction of the minimum frequency of rotation; 3 - engine stop lever; 4 — a bolt of adjustment of starting giving; 5 — a bolt of restriction of a course of the stop lever; 6 - pneumatic engine stop cylinder; 7 — a bolt of restriction of the maximum frequency of rotation.
When the key of the instrument and starter switch lock is turned to the fixed position “I”, power is supplied to the holding winding of the stop solenoid, and when the key is further turned to the non-fixed position “II”, power is also supplied to the retracting winding of the electromagnet, the electromagnet rod, overcoming the force of its own spring, extends and releases lever 3 (Figure 47). Lever 3 under the action of spring 33 (Figure 44) returns to its working position, and the starting spring 6 (Figure 45) through the rack lever 7 will return the injection pump racks to the position corresponding to the maximum fuel supply required to start the engine. When the instrument and starter switch lock key is moved from the non-fixed position “II” to the fixed position “I”, the retracting winding of the electromagnet is disconnected from the power source and the stem of the stop solenoid remains in the working position only due to the holding winding.
ATTENTION!
Checking and adjustment of the injection pump, as well as the replacement of plunger pairs, sealing rings of the injection pump sections must be carried out in a specialized workshop by a qualified specialist.
IT IS STRICTLY FORBIDDEN to install other models on the 740.30-260 injection pump engine in order to avoid deterioration in the quality of the engine's working process, an increase in toxicity and opacity of exhaust gases, as well as engine failure!
Fuel supply corrector for charge air pressure (Figure 48).
Figure 48. Corrector for fuel supply by charge air pressure: 1 - corrector housing; 2 - corrector spool; 3 - thrust ring; 4 - membrane housing gasket; 5 - washer; 6 - bolt; 7 - corrector spring; 8 - membrane body; 9 - sealing ring; 10 - nut; 11 - adjusting screw; 12 - corrector lever; 13 - axis of the lever; 14 - sealing ring; 15 - adjusting screw; 16 - nut; 17 - stem bushing; 18 - nut; 19 - washer; 20 - bolt; 21 - membrane cover; 22 - membrane; 23 - plate; 24 - membrane rod; 25 - spring plate; 26 - corrector piston; 27 - piston spring; 28 - nut; 29 - hairpin; 30 - nut; 31 - stud tip.
The charge air pressure corrector reduces the fuel supply when the charge air pressure drops below 40 ... 45 kPa (0.4 ... 0.45 kgf / cm2), thereby providing thermal protection to the engine and limiting the smoke of exhaust gases. In the body of the corrector 1, a piston 26 with a spool 2 is installed. The spring 27 acts on the piston, fixed by a plate 25 and a ring 3. A stud 29 with a tip 31, which is a nominal stop in the regulator, is wrapped and locked with a nut 28 into the piston. The tip is locked with a nut 30. The spool 2 is acted upon by a spring 7, the pretension of which can be changed by an adjusting screw 11.
Membrane body 8 is attached to corrector body 1 through gasket 4. Membrane unit with stem is installed in it (details 24,16,17,23,22, 19, 18). The membrane is clamped between the body 8 and the cover 21. In the body of the membrane 8 on the axis of the lever 13 there is a corrector lever 12, the rotation of which is limited by the adjusting screw 15.
Corrector of fuel supply of not direct action; when the charge air pressure changes in the membrane cavity, the position of the spool changes, which, in turn, determines the position of the corrector piston.
Oil is supplied under pressure from the engine lubrication system into the cavity “A” between the corrector body 1 and piston 26 through a threaded hole and a 0.7 mm jet in the corrector body (not shown in the figure). The piston under the action of this pressure, compressing the spring 27, moves to the left until the windows in the piston and spool open and the oil goes to the drain. In this case, a constant oil flow through the corrector is established. When changing the position of the spool, the piston moves after it (following system).
Through the threaded hole of the cover 21, air is supplied from the engine intake manifold into the membrane cavity. When the air pressure drops below 0.04 MPa (0.4 kgf / cm2), the force of the corrector spring 7 acting on the spool becomes greater than the force created by the charge air pressure on the membrane and transmitted through the membrane rod and the corrector lever also to the spool. The spool moves to the right until the balance of forces acting on it is reached. Following the spool, the piston with pin 29 and tip 31 also moves to the right, moving the regulator lever 8 resting against it to the right (Figure 45). Following the regulator lever, under the action of the centrifugal forces of the weights, the levers 9.2 and 7 with the pump rails move in the direction of reducing the fuel supply.
Corrector adjustment. The corrector has two external adjustments - screws 11 and 15 (Figure 48). Screw 11 changes the pretension of the corrector spring 7, while changing the beginning of the corrector operation. If it is necessary to increase the value of the charge air pressure at which the corrector starts to operate, then the screw 11 is turned in, increasing the preload of the spring 7.
Screw 15 regulates the nominal cyclic fuel supply. When screw 15 is turned out, the fuel supply increases.
If it becomes necessary to remove the corrector, then it is first necessary to measure the protrusion of the tip of the stud 31 relative to the rear end of the injection pump housing, and after installing the corrector in place, restore the value of this protrusion and lock the tip with nut 30.
The high pressure fuel pump drive is shown in Figure 49. It consists of a high pressure fuel pump drive shaft 6 with packages of front 7 and rear 8 compensating plates, a driven half-coupling 2, a driven half-coupling flange 3, a centering flange 4, a leading half-coupling 9 and centering bushings 5. Each package of compensating plates consists of of 5 plates with a thickness of 0.5 mm each.
Figure 49. High pressure fuel pump drive: 1 - high pressure fuel pump housing; 2 - driven half-coupling; 3 - flange of the driven half-coupling; 4 - centering flange; 5 - centering sleeve; 6 - drive shaft; 7, 8 - a package of compensating plates; 9 - leading coupling half; 10 - coupling bolt; 11 - key; 12 - nut; 13 — a bolt of a conducted half-coupling.
ATTENTION!
All bolts in the injection pump drive must be of strength class R100 and tightened to a torque of 65..75 N m (6.5 ... 7.5 kgf m). All bolts must be checked for tightness with a torque wrench. Before installing the bolts, check the presence of the centering sleeves. Deformation (bending) of the front and rear compensating plates is not allowed. Coupling bolt 10 of the drive coupling must be tightened last.
The fuel fine filter is shown in Figure 50. It is designed for the final purification of fuel from small particles before entering the high-pressure fuel pump. The filter is installed at the highest point of the fuel supply system to collect and remove air into the tank along with part of the fuel through a valve (Figure 51) installed at the bypass from the filter.
Figure 50. Fine fuel filter: 1 - cover; 2 - bolt; 3 - sealing washer; 4 - cork; 5, 6 - gaskets; 7 - filter element; 8 - cap; 9 - filter element spring; 10 - drain plug; 11 - rod.
ATTENTION!
When replacing filter elements, it is necessary to strictly observe the rules for servicing the fuel supply system. Do not allow contaminants to enter the system and use filter elements only of the following models 740.1117040-01, 740.1117040-02, 740.1117040-04.
The valve is shown in Figure 51. When the pressure in cavity “A” of fuel supply reaches 25…45 kPa (0.25…0.45 kgf/cm2), ball 4 moves and fuel flows from cavity “A” into cavity “B” through the 5 valve jet. At a pressure of 200 ... 240 kPa (2 ... 2.4 kgf / cm2), the valve is fully opened and fuel is bypassed into the fuel tank through cavity "B".
Figure 51. Valve: 1 - nut; 2 - valve body; 3 - spring; 4 - ball; 5 - jet; 6 - fuel fine filter cover.
fuel priming pump 13 (Figure 44) is designed to supply fuel from the tank through the coarse and fine filters and the fuel priming pump to the inlet cavity of the injection pump.
The pump is mounted on the rear cover of the regulator, it is driven by an eccentric 19 located at the rear end of the injection pump camshaft. In the pump housing there is a piston, piston spring, rod bushing 47 and pusher rod 48, inlet and discharge valves with springs. The eccentric 19 through the roller 49, the pusher 15 and the rod 48 informs the piston of the fuel priming pump reciprocating motion.
The diagram of the pump operation is shown in Figure 52. When the pusher 9 is lowered, the piston 1 moves down under the action of the spring 4. A vacuum is created in cavity "A" and inlet valve 2, compressing spring 3, passes fuel into cavity "A". At the same time, the fuel in the discharge cavity "B" is forced out into the line "D", while the valve 5 closes under the action of the spring 6, eliminating the flow of fuel from the cavity "B" into the cavity "A".
When the piston 1 moves upwards, the fuel filling the cavity "A" through the discharge valve 5 enters the cavity "B" under the piston, while the inlet valve closes. With an increase in pressure in the discharge line, the piston does not complete its full stroke after the pusher, but remains in a position that is determined by the balance of the fuel pressure force on the one hand and the spring force on the other.
fuel priming pump 10 (Figure 52) serves to fill the fuel system with fuel before starting the engine and remove air from it.
Figure 52. Scheme of operation of the fuel priming and fuel priming pumps: 1 - piston; 2 - inlet valve; 3.6 - valve springs; 4 - piston spring; 5 - discharge valve; 7 - pusher spring; 8 - eccentric; 9 - pusher; 10 - fuel priming pump; 11 - piston; 12 - inlet valve; 13 - discharge valve; 14 - springs
The pump consists of a housing, piston, cylinder, inlet and discharge valves.
The fuel system should be pumped using the pump piston, having previously unlocked it by turning it counterclockwise.
When the piston 11 moves upwards, a vacuum is created in the space below it. The inlet valve 12, compressing the spring 14, opens and the fuel enters the cavity "D" of the pump. When the piston moves down, the inlet valve closes and the discharge valve 13 opens, fuel under pressure enters the discharge line, ensuring the removal of air from the engine fuel system through the FTOT valve and the injection pump bypass valve.
After pumping the system, it is necessary to lower the piston and fix it by turning it clockwise. In this case, the piston will press against the end of the cylinder through the rubber gasket, sealing the suction cavity of the fuel priming pump.
ATTENTION! It is not allowed to start the engine with an unsecured piston due to the possibility of air leakage through the piston seal.
Fuel lines are divided into low pressure fuel lines - 0.4 ... 2 MPa (4 ... 20 kgf / cm2) and high pressure more than 20 MPa (200 kgf / cm2).
The low pressure fuel lines are made of a steel pipe with a section of 10 1 mm with brazed ends.
High-pressure fuel lines of equal length (l=595 mm) are made of steel tubes with an internal diameter of 2 + 0.05 mm by landing at the ends of connecting cones with compression washers and union nuts for connection with high-pressure fuel pump fittings and injectors.
The fuel lines are stapled to the intake manifolds to prevent damage from vibration.
